App 2.45.2: Halloween's song banner waves

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

.claude/skills/car-logs/SKILL.md

@@ -0,0 +1,95 @@
+---
+name: car-logs
+description: Download the signal recordings the MG4 sent to the car server (fetch-logs) and read them. Use when the owner says a recording is on the server, asks to get, download or look at the car's logs or recordings, or after a test drive with the signal recorder.
+---
+
+# Fetch and read the car's recordings
+
+The app's signal recorder (Logs tab, `SignalRecorder`) sends each finished recording to the
+car server (`LogOutbox`, `PUT /v1/logs/{name}`); the server keeps the newest 200
+(`server/logs.go`). `fetch-logs` in the dev shell downloads the ones not yet in `logs/`.
+
+## Fetch
+
+```sh
+nix develop -c fetch-logs
+```
+
+It prints each new file (`logs/signal-recording-YYYYMMDD-HHMMSS.txt`) and `fetch-logs: N new`.
+The token comes from `~/.config/nilsmg4/logs-token` (the server's `LOGS_TOKEN`) and goes only in
+a header.
+
+- **Never print, cat or echo the token**, and never pass it on a command line you show. Do not
+  read the token file.
+- `no token`: ask the owner to put the server's `LOGS_TOKEN` in `~/.config/nilsmg4/logs-token`
+  (and in `k8s/secrets/secrets.yaml`, then apply it). Do not create or fill it yourself.
+- HTTP 401: the file and the server's Secret differ. HTTP 404: reading is off (no
+  `LOGS_TOKEN` on the server) or the server is older than 2.9.0. The owner applies manifests and
+  Secrets; never run `kubectl` against the cluster, not even read-only.
+- `0 new`: nothing arrived. In the car, the Logs tab says "Sent to the server." or how many wait
+  and why (no server set up, server not reached, an HTTP status); the car retries every 2
+  minutes while the service runs.
+
+## Read
+
+The files are plain text but `file` may call them data; search with `rg -a`. Newest first:
+`ls -t logs/`. If the owner said what they did and when (e.g. "ACC on at 08:50, set speed
+100→90 at 08:51"), line those times up with the timeline.
+
+A recording has four parts, in this order:
+
+1. Header: captures, start time, app version.
+2. **Steering-wheel keys and notes.** The first note says whether listening worked:
+   `listening to N assistance properties (M refused)`, or `not possible (<reason>)`.
+3. **Assistance properties heard** (`EVHardware.listenToProperties` on `AssistBlock`, the
+   `0x21x0A1xx` block): change events, properties whose value changed first. This is where a
+   value shows up that the head unit fills only while someone listens.
+4. **Changed values (polled)**, rarest first, then **Everything, in order**: every capture
+   (about every 5 s) with what changed since the last.
+
+Useful cuts:
+
+```sh
+rg -a 'listening to' logs/<file>                                   # did listening work
+awk '/^Assistance properties heard/,/^$/' logs/<file>              # what listening heard
+rg -a 'A15B|A15A' logs/<file>                                      # one property's history
+rg -a 'getLatestSpeed' logs/<file> | head                          # the car's speed over time
+```
+
+Known leads (SPECS.md, 2026-10-27): `0x2160A15B` is `AAD_EPTCCTRGTSPD`, by its name the cruise
+control's target speed (0.0 when only polled); `0x2140A15A` moved between 3 and 7;
+`0x2160A1A3`/`0x2160A1A4` counted up by 0.1. A value that tracks what the owner did at the
+times they name is a lead; say how sure it is, and that it is not confirmed until a second
+drive shows the same.
+
+## Music-sources checks
+
+`fetch-logs` also brings `media-probe-YYYYMMDD-HHMMSS.txt` (Logs tab, "Check music sources",
+`MediaProbe`). Three parts: audio players (use, app, state), active media sessions with state
+and song (TITLE, ARTIST, ALBUM, ALBUM_ART as a size or ALBUM_ART_URI), and the media browser
+services by name (2.42.1 on; 2.42.0 also connected to them, which stopped the music). CarPlay's
+session is `com.allgo.remoteui.mediabrowserservice`, Bluetooth's `com.android.bluetooth`. Ask what was playing
+when the check ran.
+
+## Sound checks
+
+`fetch-logs` also brings `sound-probe-YYYYMMDD-HHMMSS.txt` (Logs tab, "Check sound",
+`SoundProbe`, 2.43.3 on): permissions, which session plays, then one line a second of the audio
+analyser's peak, bass, mid, treble and rms, and a result line. Levels only, no sound. The peak has
+to move for music to count as heard. Ask what was playing when the check ran, and whether the
+music kept playing and any prompt came up.
+
+## Update checks
+
+`fetch-logs` also brings `update-check-YYYYMMDD-HHMMSS.txt` (each Settings → Check for updates,
+`UpdateHook`, 2.43.5 on): the networks Android sees, whether the server's name resolves, the
+result and, on a failure, whether `www.gstatic.com/generate_204` answers (204: the internet
+works, so look at the server). A report written offline arrives once the car is back online, or
+is on a USB stick that was plugged in.
+
+## Rules
+
+- Recordings and checks are the car's data: `logs/`, `/signal-recording-*.txt` and
+  `/media-probe-*.txt`, `/sound-probe-*.txt`, `/update-check-*.txt` are gitignored. Never
+  commit, publish or upload them anywhere.
+- Findings that change what the project knows go into a `SPECS.md` done-log entry, as usual.

.gitignore

@@ -41,3 +41,10 @@ mise.local.toml
 
 # CarPlay diagnostic exports: vendor software, never committed
 /dump/
+
+# The car's own recordings (fetch-logs, or copied off a USB stick): its data, not the code's.
+/logs/
+/signal-recording-*.txt
+/media-probe-*.txt
+/sound-probe-*.txt
+/update-check-*.txt

AGENTS.md

@@ -21,7 +21,8 @@ MG4 head unit (Android 9, AAOS, MT2712)
 - **server/** — Go 1.27 API at `https://car.k8s.stinnesbeck.com`: stores telemetry, consumption
   and charging in InfluxDB, pairs cars by QR code, carries settings typed on a phone, relays
   app releases from the private forge, and serves the roads for the Grid's map from
-  OpenStreetMap (Overpass). It does **not** talk to ABRP. See `server/README.md`.
+  OpenStreetMap vector tiles (OpenFreeMap), fetched per tile on demand and cached on a volume, and keeps the signal recordings the car sends
+  (read with their own token, `fetch-logs`). It does **not** talk to ABRP. See `server/README.md`.
 - **k8s/** — plain Kubernetes manifests (InfluxDB, server, Grafana with three provisioned
   dashboards, Traefik routes). See `k8s/README.md`.
 - **EVHardware/** — vendored shared vehicle layer (PolyForm Noncommercial, see `LICENSE.md`).
@@ -76,12 +77,12 @@ Repository: `ssh://git@git.stinnesbeck.com:2222/nils/mg4.git` (remote `origin`),
 
 | Tab | Contents |
 |---|---|
-| Overview | value tiles (battery, range, range/usage/energy since start, 5-min averages of range, usage, power, speed), vehicle info (odometer, lease allowance and the odometer against it), tyre pressures; read every 0.2 s on a background thread. Styles (Settings → Overview style): Tiles, Gauges (`GaugeView` needles), Cockpit (`RingView` rings, `TraceView` power trace), Retro (`RetroView`, seven-segment VFD), Futuristic (`FlowView`, animated energy flow), Sci-fi (`SciFiView`, starship console), Cartoon (`CartoonView`), MG (`OctagonView`, octagonal dials after the classic MG dashboards), and on `ClusterCanvasView`: Minimal, Terminal, Nixie tubes, Chronograph, Grid (`GridView`, neon lines over a moving grid floor, power as a light-cycle trail from `ClusterValues.powerTrail`), Grid with map (the same `GridView` over the roads round the car: GPS while it is shown, tiles from the server's `/v1/map/roads` through `MapRoads`, cached in `files/map`; `RoadTile`, `MapGeometry`), Time circuits (`TimeCircuitsView`, the time machine's LED rows with `Segments14` letters and a flux capacitor), Quest (`QuestView`, a fantasy game interface), Visor (`VisorView`, a helmet display with a motion tracker of the power trail), Empire (`EmpireView`, a strategy game with an isometric world and ages by odometer, `EmpireAge`); the drawn styles share `ClusterValues`. A style shown in its own palette (Sci-fi, Cartoon, Nixie, Time circuits, Quest, Empire; Retro, Terminal, Grid and Visor with "Original") gives the whole app its colours (`StylePalette`, `res/values/style_palettes.xml`) instead of the accent colour. A button in the navigation's header hides the navigation for a full-width Overview (`PREF_OVERVIEW_FULLSCREEN`); a swipe in from the left edge (`EdgeSwipe`) brings it back; without the app's own full screen the car's sidebar takes that edge, so a tab at the left edge (`edge_tab`) is tapped or swiped instead. Pages change only by the navigation (the pager's own swiping is off) |
+| Overview | value tiles (battery, range, range/usage/energy since start, 5-min averages of range, usage, power, speed, and under the battery what plays: `NowPlaying` picks from the media sessions `NowPlayingWatcher` follows — listened to only, never connected to, nothing logged or sent; Tiles and Halloween, Settings → "Show what's playing", `PREF_NOW_PLAYING`, on by default), vehicle info (odometer, lease allowance and the odometer against it), tyre pressures; read every 0.2 s on a background thread. Styles (Settings → Overview style): Tiles, Gauges (`GaugeView` needles), Cockpit (`RingView` rings, `TraceView` power trace), Retro (`RetroView`, seven-segment VFD), Futuristic (`FlowView`, animated energy flow), Sci-fi (`SciFiView`, starship console), Cartoon (`CartoonView`), MG (`OctagonView`, octagonal dials after the classic MG dashboards), and on `ClusterCanvasView`: Minimal, Terminal, Nixie tubes, Chronograph, Grid (`GridView`, neon lines over a moving grid floor, power as a light-cycle trail from `ClusterValues.powerTrail`), Grid with map (the same `GridView` over the roads round the car, top-down: GPS while it is shown, tiles from the server's `/v1/map/roads` through `MapRoads`, cached in `files/map`; `RoadTile`, `MapGeometry`; the map is `MapLayerView`, a hardware layer drawn once and moved and turned by the GPU every display frame), Time circuits (`TimeCircuitsView`, the time machine's LED rows with `Segments14` letters and a flux capacitor), Quest (`QuestView`, a fantasy game interface), Visor (`VisorView`, a helmet display with a motion tracker of the power trail), Empire (`EmpireView`, a strategy game with an isometric world and ages by odometer, `EmpireAge`), Día de Muertos (`MuertosView`, an ofrenda: papel picado, candles, a calavera in a ring of marigolds), Halloween (`HalloweenView`, a jack-o'-lantern, a potion flask, a tombstone on a graveyard hill), both counting with `Tally`, the pumpkin's light flaring on the kick drum while on screen, when "Pumpkin light follows the music" is on (off by default, `PREF_MUSIC_LIGHT`; `MusicTap`, `MusicPulse`: Android's audio analyser, 40–120 Hz, jumps not levels; Bluetooth and CarPlay, not the radio); the drawn styles share `ClusterValues`. A style shown in its own palette (Sci-fi, Cartoon, Nixie, Time circuits, Quest, Empire, Día de Muertos, Halloween; Retro, Terminal, Grid and Visor with "Original") gives the whole app its colours (`StylePalette`, `res/values/style_palettes.xml`) instead of the accent colour. A button in the navigation's header hides the navigation for a full-width Overview (`PREF_OVERVIEW_FULLSCREEN`); a swipe in from the left edge (`EdgeSwipe`) brings it back; without the app's own full screen the car's sidebar takes that edge, so a tab at the left edge (`edge_tab`) is tapped or swiped instead. Pages change only by the navigation (the pager's own swiping is off) |
 | Consumption / Charging | period totals, daily log, charging sessions and curve |
 | Live data | on/off, ABRP API key and user token, upload frequency |
 | Server | URL, pairing by QR, ingest token, installation ID (read-only), config import |
 | Settings | drive mode (Eco, Normal, Sport, Snow, Custom; the lit one is what the car reports; changes only in P at a standstill, `DriveModeWrite`; "Set at start" sets the last confirmed choice again when the service starts with the head unit), full screen, voice key, Overview style with the accent colour beside it (offered only for styles drawn in it, `OverviewStyle.usesAccent`; Retro, Terminal, Grid (and Grid with map, sharing Grid's choice) and Visor add "Original" for their own palette, `hasOriginal`), tyre unit, battery and charging price (one card on wide screens), version, update check, install from USB, About |
-| Logs | signal recorder (`SignalRecorder`/`SignalRecording`: every property and vendor getter via `VendorSurfaceProbe.capture`, again and again for 3 minutes, plus steering-wheel key broadcasts; lists what changed, rarest first; saved to the app and a USB stick; how to find where the car publishes something), update log (every install step, with the platform's words), upload log |
+| Logs | signal recorder (`SignalRecorder`/`SignalRecording`: every property and vendor getter via `VendorSurfaceProbe.capture`, again and again for 3 minutes, plus change events of the driver-assistance block it subscribes to, `EVHardware.listenToProperties` with `AssistBlock`, and steering-wheel key broadcasts; lists what changed, rarest first; saved to the app, a USB stick and the server, through `LogOutbox`, which sends it again later when the car is offline; how to find where the car publishes something), music-sources check (`MediaProbe`: audio players and the active media sessions, CarPlay's and Bluetooth's among them, with their song, and the media browser services by name — never connected to: binding them stopped the music in 2.42.0; saved and sent like a recording), sound check (`SoundProbe`, `SoundLevels`: on a tap, 10 seconds of levels from Android's audio analyser, to learn whether it hears what plays; saved and sent like a recording), update log (every check and install step, with the platform's words; a check also writes down the networks, the server's name lookup and, when it fails, an internet test, `UpdateNetworkCheck`, `UpdateDiagnosis`, and saves a report like a recording), upload log |
 
 Key classes (`app/src/main/java/com/evsuite/abrp/`): `AbrpUploadService` (foreground service,
 15 s tick), `TelemetryUploader` (+ `TelemetryQueue`, persisted), `TelemetryPayload` (server
@@ -110,6 +111,7 @@ nix develop                                   # JDK 21, Android SDK, Go
 ./gradlew testStableDebugUnitTest testUnstableDebugUnitTest lintStableDebug
 build-car                                     # build/car/NilsMG4-unstable-<version>.apk + .sha256
 publish-car                                   # pre-release car-<version> on the forge (needs a token)
+fetch-logs                                    # the car's recordings from the server into logs/ (needs LOGS_TOKEN; skill car-logs)
 cd server && go vet ./... && go test ./... && govulncheck ./...
 ```
 

EVHardware/lib/src/main/java/com/evsuite/hardware/AssistBlock.kt

@@ -0,0 +1,24 @@
+package com.evsuite.hardware
+
+/**
+ * The block of vendor properties the head unit's driver-assistance manager
+ * (`CarAdvancedAssistedDrivingManager`, its `AAD_*` ids) lives in: global vendor properties
+ * `0x21x0A1xx`, of any value type — `0x2140A101` (int) to `0x2160A15B` (float, `AAD_EPTCCTRGTSPD`,
+ * by its name the cruise control's target speed) and the rest of the same block. Used to choose
+ * what the signal recorder listens to; nothing here is ever written. Pure, unit-tested.
+ */
+object AssistBlock {
+
+    private const val GROUP_MASK = 0xF0000000.toInt()
+    private const val GROUP_VENDOR = 0x20000000
+    private const val AREA_MASK = 0x0F000000
+    private const val AREA_GLOBAL = 0x01000000
+    private const val BLOCK_MASK = 0x0000FF00
+    private const val BLOCK = 0x0000A100
+
+    /** Whether [propertyId] is a global vendor property in the assistance block. */
+    fun contains(propertyId: Int): Boolean =
+        propertyId and GROUP_MASK == GROUP_VENDOR &&
+            propertyId and AREA_MASK == AREA_GLOBAL &&
+            propertyId and BLOCK_MASK == BLOCK
+}

EVHardware/lib/src/main/java/com/evsuite/hardware/EVHardware.kt

@@ -320,6 +320,144 @@ object EVHardware {
         ignitionCallbacks.remove(callback)
     }
 
+    // -------------------------------------------------------------------------
+    // Listening to properties (the app's signal recorder) — read only
+    // -------------------------------------------------------------------------
+
+    /** Why the last [listenToProperties] returned null, in a few words; null after a success. */
+    @Volatile var listenProblem: String? = null
+        private set
+
+    /** A subscription made by [listenToProperties]; [close] ends it. */
+    class PropertyListening internal constructor(
+        /** Properties subscribed to, and those the car service refused. */
+        val subscribed: Int,
+        val refused: Int,
+        private val stop: () -> Unit,
+    ) : AutoCloseable {
+        override fun close() = stop()
+    }
+
+    /**
+     * Subscribes to every CarPropertyManager property whose id [admit] accepts, the way the
+     * head unit's own managers do (`CarAdvancedAssistedDrivingManager` registers each of its
+     * `AAD_*` ids for change events and never polls them), and hands each change event to
+     * [onEvent] as (property id, area, value as text) on the car service's thread. A vendor HAL
+     * may fill a property from the car network only while someone listens, so a poll alone can
+     * read its default. ON_CHANGE properties are asked for every change, CONTINUOUS ones for
+     * 1 Hz within their limits. Read only: nothing is set. Null when there is no
+     * CarPropertyManager or no way to subscribe, with the reason in [listenProblem];
+     * [PropertyListening.close] unsubscribes.
+     *
+     * Android 9's car library (the MG4's) names the calls `registerListener(CarPropertyEventListener,
+     * int, float)` and `unregisterListener`; Android 10 renamed them `registerCallback` and
+     * `unregisterCallback`. Both are looked for. Unsubscribing goes property by property: the
+     * one-argument `unregisterListener` of Android 9 removes entries from the list it walks and so
+     * leaves every other property subscribed.
+     */
+    fun listenToProperties(admit: (Int) -> Boolean, onEvent: (Int, Int, String) -> Unit): PropertyListening? {
+        listenProblem = null
+        val cpm = sCarPropertyManager ?: run {
+            listenProblem = "no car service"
+            return null
+        }
+        return try {
+            val methods = cpm.javaClass.methods
+            val register = methods.firstOrNull {
+                (it.name == "registerListener" || it.name == "registerCallback") && it.parameterCount == 3 &&
+                    it.parameterTypes[1] == Int::class.javaPrimitiveType &&
+                    it.parameterTypes[2] == Float::class.javaPrimitiveType
+            } ?: run {
+                listenProblem = "no way to subscribe"
+                return null
+            }
+            val callbackType = register.parameterTypes[0]
+            val unregister = methods.firstOrNull {
+                it.name == register.name.replaceFirst("register", "unregister") && it.parameterCount == 2 &&
+                    it.parameterTypes[0] == callbackType && it.parameterTypes[1] == Int::class.javaPrimitiveType
+            }
+            val unregisterAll = methods.firstOrNull {
+                it.name == register.name.replaceFirst("register", "unregister") && it.parameterCount == 1 &&
+                    it.parameterTypes[0] == callbackType
+            }
+            if (!callbackType.isInterface) {
+                listenProblem = "unexpected listener type ${callbackType.simpleName}"
+                return null
+            }
+            val proxy = Proxy.newProxyInstance(callbackType.classLoader, arrayOf(callbackType)) { self, method, args ->
+                when (method.name) {
+                    "onChangeEvent" -> {
+                        val cpv = args?.getOrNull(0)
+                        if (cpv != null) {
+                            try {
+                                val type = cpv.javaClass
+                                val id = type.getMethod("getPropertyId").invoke(cpv) as Int
+                                val area = type.getMethod("getAreaId").invoke(cpv) as Int
+                                onEvent(id, area, com.evsuite.hardware.probe.VendorSurfaceRules.render(
+                                    type.getMethod("getValue").invoke(cpv)))
+                            } catch (e: Exception) {
+                                AppLogger.d(TAG, "listen: event unreadable: ${e.readFailureReason()}")
+                            }
+                        }
+                        null
+                    }
+                    "onErrorEvent" -> {
+                        val id = args?.getOrNull(0) as? Int
+                        val area = args?.getOrNull(1) as? Int
+                        if (id != null) onEvent(id, area ?: AREA_GLOBAL, "error event")
+                        null
+                    }
+                    "equals" -> self === args?.getOrNull(0)
+                    "hashCode" -> System.identityHashCode(self)
+                    "toString" -> "PropertyListening"
+                    else -> null
+                }
+            }
+            val configs = cpm.javaClass.getMethod("getPropertyList").invoke(cpm) as? List<*> ?: return null
+            val subscribedIds = ArrayList<Int>()
+            var refused = 0
+            for (config in configs) {
+                if (config == null) continue
+                val type = config.javaClass
+                val id = runCatching { type.getMethod("getPropertyId").invoke(config) as Int }.getOrNull() ?: continue
+                if (!admit(id)) continue
+                val continuous = runCatching { type.getMethod("getChangeMode").invoke(config) as Int }.getOrNull() == 2
+                val rate = if (!continuous) 0f else {
+                    val min = runCatching { type.getMethod("getMinSampleRate").invoke(config) as Float }.getOrNull() ?: 0f
+                    val max = runCatching { type.getMethod("getMaxSampleRate").invoke(config) as Float }.getOrNull() ?: 1f
+                    1f.coerceIn(min, maxOf(min, max))
+                }
+                try {
+                    if (register.invoke(cpm, proxy, id, rate) == false) refused++ else subscribedIds.add(id)
+                } catch (e: Exception) {
+                    refused++
+                    AppLogger.d(TAG, "listen: 0x%08X refused: %s".format(id, e.readFailureReason()))
+                }
+            }
+            AppLogger.i(TAG, "listening to ${subscribedIds.size} properties ($refused refused) via ${register.name}")
+            PropertyListening(subscribedIds.size, refused) {
+                for (id in subscribedIds) {
+                    try {
+                        if (unregister != null) unregister.invoke(cpm, proxy, id)
+                    } catch (e: Exception) {
+                        AppLogger.d(TAG, "listen: unsubscribe 0x%08X failed: %s".format(id, e.readFailureReason()))
+                    }
+                }
+                if (unregister == null) {
+                    try {
+                        unregisterAll?.invoke(cpm, proxy)
+                    } catch (e: Exception) {
+                        AppLogger.d(TAG, "listen: unsubscribe failed: ${e.readFailureReason()}")
+                    }
+                }
+            }
+        } catch (e: Exception) {
+            listenProblem = e.readFailureReason()
+            AppLogger.w(TAG, "listenToProperties: ${e.readFailureReason()}")
+            null
+        }
+    }
+
     /** Unregisters the CarPropertyManager proxy (call from Service.onDestroy). */
     fun unregisterIgnitionPropertyCallback() {
         val cpm = sCarPropertyManager ?: return

EVHardware/lib/src/test/java/com/evsuite/hardware/AssistBlockTest.kt

@@ -0,0 +1,29 @@
+package com.evsuite.hardware
+
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class AssistBlockTest {
+
+    @Test
+    fun `the assistance manager's properties are in the block`() {
+        // First and last int, the target speed and the object distance (floats).
+        for (id in intArrayOf(0x2140A101, 0x2140A171, 0x2160A15B, 0x2160A12C, 0x2160A114)) {
+            assertTrue("0x%08X".format(id), AssistBlock.contains(id))
+        }
+    }
+
+    @Test
+    fun `other properties are not`() {
+        for (id in intArrayOf(
+            0x2140A0FF, // the block before
+            0x2140A201, // the block after
+            0x11400400, // a standard (system) property
+            0x2340A101, // not global
+            0x0140A101, // no group
+        )) {
+            assertFalse("0x%08X".format(id), AssistBlock.contains(id))
+        }
+    }
+}

EVHardware/lib/src/test/java/com/evsuite/hardware/PropertyListeningTest.kt

@@ -0,0 +1,105 @@
+package com.evsuite.hardware
+
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class PropertyListeningTest {
+
+    class Config(val propertyId: Int, val changeMode: Int, val minSampleRate: Float, val maxSampleRate: Float)
+    class Value(val propertyId: Int, val areaId: Int, val value: Any)
+
+    /** Shaped like Android 9's CarPropertyManager, the car's: registerListener, and an
+     *  unregisterListener(listener) that skips every other property as the car's does. */
+    class Android9Manager(private val configs: List<Config>) {
+        interface CarPropertyEventListener {
+            fun onChangeEvent(value: Any?)
+            fun onErrorEvent(propertyId: Int, areaId: Int)
+        }
+
+        val active = LinkedHashMap<Int, MutableList<CarPropertyEventListener>>()
+        val rates = HashMap<Int, Float>()
+
+        fun getPropertyList(): List<Config> = configs
+
+        fun registerListener(listener: CarPropertyEventListener, propertyId: Int, rate: Float): Boolean {
+            active.getOrPut(propertyId) { ArrayList() }.add(listener)
+            rates[propertyId] = rate
+            return true
+        }
+
+        fun unregisterListener(listener: CarPropertyEventListener) {
+            val ids = active.keys.toMutableList()
+            var i = 0
+            while (i < ids.size) {
+                unregisterListener(listener, ids[i])
+                if (active[ids[i]] == null) ids.removeAt(i) // as SparseArray.remove under keyAt(i)
+                i++
+            }
+        }
+
+        fun unregisterListener(listener: CarPropertyEventListener, propertyId: Int) {
+            val list = active[propertyId] ?: return
+            list.remove(listener)
+            if (list.isEmpty()) active.remove(propertyId)
+        }
+
+        fun fire(propertyId: Int, value: Any) {
+            active[propertyId]?.toList()?.forEach { it.onChangeEvent(Value(propertyId, 0x01000000, value)) }
+        }
+    }
+
+    class NoListeners {
+        fun getPropertyList(): List<Config> = emptyList()
+    }
+
+    private val field = EVHardware::class.java.getDeclaredField("sCarPropertyManager").apply { isAccessible = true }
+
+    @After
+    fun reset() = field.set(null, null)
+
+    @Test
+    fun `subscribes through Android 9's registerListener and unsubscribes every property`() {
+        val manager = Android9Manager(listOf(
+            Config(0x2160A15B, 1, 0f, 0f),     // in the block, on change
+            Config(0x2140A15A, 1, 0f, 0f),
+            Config(0x2160A1A3, 2, 0f, 10f),    // continuous
+            Config(0x2140A101, 1, 0f, 0f),
+            Config(0x11400400, 1, 0f, 0f),     // outside the block
+        ))
+        field.set(null, manager)
+        val heard = ArrayList<String>()
+
+        val listening = EVHardware.listenToProperties(AssistBlock::contains) { id, area, value ->
+            heard += "%08X/%d=%s".format(id, area, value)
+        }
+
+        assertNotNull(EVHardware.listenProblem, listening)
+        assertEquals(4, listening!!.subscribed)
+        assertEquals(0, listening.refused)
+        assertEquals(setOf(0x2160A15B, 0x2140A15A, 0x2160A1A3, 0x2140A101), manager.active.keys)
+        assertEquals(0f, manager.rates[0x2160A15B])
+        assertEquals(1f, manager.rates[0x2160A1A3])
+
+        manager.fire(0x2160A15B, 90f)
+        assertEquals(1, heard.size)
+        assertTrue(heard[0], heard[0].startsWith("2160A15B/16777216="))
+
+        listening.close()
+        assertTrue(manager.active.toString(), manager.active.isEmpty())
+    }
+
+    @Test
+    fun `says why when there is no way to subscribe`() {
+        field.set(null, NoListeners())
+        assertNull(EVHardware.listenToProperties(AssistBlock::contains) { _, _, _ -> })
+        assertEquals("no way to subscribe", EVHardware.listenProblem)
+
+        field.set(null, null)
+        assertNull(EVHardware.listenToProperties(AssistBlock::contains) { _, _, _ -> })
+        assertEquals("no car service", EVHardware.listenProblem)
+    }
+}

LICENSE.md

@@ -21,8 +21,10 @@ software. `LICENSE` names all of them; keep every line.
 ## Map data
 
 The roads of the "Grid with map" style are © OpenStreetMap contributors, under the
-[Open Database Licence](https://opendatacommons.org/licenses/odbl/); the style shows that line
+[Open Database Licence](https://opendatacommons.org/licenses/odbl/), in vector tiles
-whenever it draws them. The server fetches them from an Overpass API (`server/maps.go`).
+© OpenMapTiles served by [OpenFreeMap](https://openfreemap.org). The style shows
+"OpenFreeMap © OpenMapTiles · © OpenStreetMap contributors" whenever it draws them. The server
+fetches the tiles (`server/maps.go`).
 
 ## The EVHardware library
 
@@ -37,8 +39,9 @@ top. Those are Fatih's reads the car needs and upstream does not have — the ve
 ids `0x21401553`–`56`, the vendor mileage `0x21401566` for the odometer, the charging status
 from `0x2140F409`, SoC, range, power, pack voltage and current on SWI69 as on SWI68, and SWI69
 speed already in km/h — plus translated comments and, from this fork, the gear's raw code
-(`EVHardware.getGearRaw`, `EnergySnapshot.gearRaw`) and a drive mode write without the binder
+(`EVHardware.getGearRaw`, `EnergySnapshot.gearRaw`), a drive mode write without the binder
-fallback (`writeDriveModeProperty`). To take upstream again, merge three ways with
+fallback (`writeDriveModeProperty`), and read-only listening to properties for the signal
+recorder (`listenToProperties`, `AssistBlock`). To take upstream again, merge three ways with
 `e4e1158` as the base.
 
 The car app links EVHardware into its APK, so the **built app** may only be used and passed on

OTA.md

@@ -89,7 +89,11 @@ platform's own words, is on the Logs tab under "Updates".
 | `Installation failed: INSTALL_FAILED_… The APK is in Downloads.` | The package manager's own words. A signature error means the APK was not signed by `build-car`. |
 | `… is in Downloads — tap the file to install` | A session could not start; install from Downloads by hand. |
 
-On the car's Logs tab, or with a cable: `adb logcat -s EVABRP.Update OtaUpdater`.
+On the car's Logs tab, or with a cable: `adb logcat -s EVABRP.Update OtaUpdater`. Each check
+writes down the networks Android sees, whether the server's name resolves, its result and, when
+it fails, whether `www.gstatic.com/generate_204` answers, which tells a SIM without data from a
+server that is down. That report also goes to a USB stick and, once online, to the server
+(`update-check-*.txt`, read with `fetch-logs`). No address or token is written.
 
 ## Why a PackageInstaller session, not `pm install`
 
@@ -110,3 +114,10 @@ That screen needs a `file://` URI on the car build: a read grant on our FileProv
 when it comes from the system user (`not exported from UID 1000`), and the installer reports the
 unreadable file as "There was a problem parsing the package". On the emulator the session still
 installs silently.
+
+The refusal does not always come at once: the platform may also answer a moment later, through
+the session's result (`OtaInstallResultReceiver`). Since 2.40.1 that answer opens the installer
+screen too, as does a confirmation the platform asks for but cannot show; only **Cancel** on that
+screen ends the update there. And if the session says nothing at all for 20 s, the app abandons
+it and opens the installer screen. Before 2.40.1 a late refusal ended in a short message only:
+the update downloaded and then nothing seemed to happen.

README.md

@@ -39,7 +39,7 @@ APIs.
 
 ## Screenshots
 
-**Overview styles:** the Overview comes in eighteen looks, from an 80s fluorescent display to a
+**Overview styles:** the Overview comes in twenty looks, from an 80s fluorescent display to a
 starship console, a watch face, a neon grid (also over a map of the roads round the car), a time machine, a fantasy game, a helmet display and a strategy game. [THEMES.md](THEMES.md) shows each one, with and without the
 navigation, and what inspired it.
 
@@ -82,20 +82,20 @@ car ──live telemetry───▶ car.k8s.stinnesbeck.com (Go)
 
 The car sends live data to ABRP itself, with the ABRP credentials set on the Live data tab, so
 ABRP and the server do not depend on each other. The server stores, relays the app's updates
-from the forge and serves the roads for the Grid's map (from OpenStreetMap). The car authenticates
+from the forge and serves the roads for the Grid's map (OpenStreetMap, through OpenFreeMap). The car authenticates
 with the server using a token of its own, obtained by pairing with a phone (below).
 
 ## The app
 
 | Tab | What it shows |
 |---|---|
-| **Overview** | Battery, range, power and speed; range, usage and energy since start; 5-minute averages of range, usage, power and speed; vehicle info (odometer, lease allowance, climate setpoint) and tyre pressures. Read five times a second. Looks to choose from in Settings → Overview style: Tiles, Gauges, Cockpit, Retro, Futuristic, Sci-fi, Cartoon, MG, Minimal, Terminal, Nixie tubes, Chronograph, Grid, Grid with map, Time circuits, Quest, Visor and Empire ([THEMES.md](THEMES.md) shows them all). A style with its own colours (Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest, Empire, and Retro, Terminal, Grid and Visor with "Original"). Grid with map lays the roads round the car on the Grid's floor: the app asks the car's server for the map tile it is in (not its position), the server fetches the roads from OpenStreetMap's Overpass API and keeps them, and the GPS runs for it only while that style is on screen colours the whole app to match, e.g. turquoise for Retro. The small button next to the MG4 logo in the navigation hides the navigation for a full-width Overview; swipe in from the left edge (a faint handle marks it) to bring it back; with Settings → Full screen off, the car's own sidebar sits at that edge, so tap the small tab at the left edge (›) instead. Pages change only by the navigation, not by swiping sideways |
+| **Overview** | Battery, range, power and speed; range, usage and energy since start; 5-minute averages of range, usage, power and speed; vehicle info (odometer, lease allowance, climate setpoint) and tyre pressures. While music plays (Bluetooth, CarPlay or the radio), the title and artist; they stay on the screen and are never sent. Read five times a second. Looks to choose from in Settings → Overview style: Tiles, Gauges, Cockpit, Retro, Futuristic, Sci-fi, Cartoon, MG, Minimal, Terminal, Nixie tubes, Chronograph, Grid, Grid with map, Time circuits, Quest, Visor and Empire ([THEMES.md](THEMES.md) shows them all). A style with its own colours (Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest, Empire, and Retro, Terminal, Grid and Visor with "Original") colours the whole app to match, e.g. turquoise for Retro. Grid with map lays the roads round the car on the Grid's floor: the app asks the car's server for the map tile it is in (not its position), the server fetches only that tile from OpenFreeMap's OpenStreetMap vector tiles and keeps it, and the GPS runs for it only while that style is on screen. The small button next to the MG4 logo in the navigation hides the navigation for a full-width Overview; swipe in from the left edge (a faint handle marks it) to bring it back; with Settings → Full screen off, the car's own sidebar sits at that edge, so tap the small tab at the left edge (›) instead. Pages change only by the navigation, not by swiping sideways |
 | **Consumption** | Lifetime, last 7 and 30 days, Trip A and B (distance, energy, average consumption and speed, SOC change), and a daily log of the last four months |
 | **Charging** | The current session (SOC, voltage, current, power, energy into the battery and from the grid, time, cost) and its SOC/power curve |
 | **Live data** | Live data on/off, ABRP credentials for sending directly from the car, upload frequency |
 | **Server** | Server URL, pairing by QR code, ingest token, installation ID, config import |
 | **Settings** | Full screen, voice key, Overview style and accent colour, tyre pressure unit; drive mode (Eco, Normal, Sport, Snow, Custom: changes only in P at a standstill; the highlighted one is what the car reports; with "Set at start" the last confirmed choice is set again when the car starts, while it is still in P); battery (manual SoH, usable capacity) and charging price; entry on the phone; version, update check, install from USB stick, About |
-| **Logs** | Signal recorder (records every value the head unit offers for 3 minutes and lists what changed, to find where the car publishes something; saved to a USB stick too), update log (every install step), upload log |
+| **Logs** | Signal recorder (records every value the head unit offers for 3 minutes, listens to the driver-assistance values for every change they report, and lists what changed, to find where the car publishes something; sent to your server, and saved to a USB stick too), music-sources check (where the head unit tells what is playing, CarPlay included; read only), update log (every install step), upload log |
 
 - **Opening the app:** the MG4 launcher does not list third-party apps. **Double-press the
   voice key** on the steering wheel and the app comes to the front (switch on the Settings

SPECS.md

@@ -78,7 +78,9 @@ tyre pressures, GPS (lat, lon, elevation, heading) and the is_* flags. It does *
   (`AAD_EPTCCTRGTSPD` `0x2160A15B` 0.0, `AAD_ACC_OBJ_*` 0.0 / -128.0, modes 0). A signal recording
   of all 1,194 values while the set speed was 101, 90 and 80 km/h shows none of those numbers
   (also tried as m/s, mph and ×2/×10/×16/×64) outside the actual speed, and the ACC buttons send
-  no key broadcast. Most likely only the instrument cluster has it.
+  no key broadcast. Most likely only the instrument cluster has it. Not yet tried: listening
+  (subscribing) instead of polling, as the head unit's own manager does — the recorder does it
+  since 2.40.3; a drive with ACC will tell.
 
 ## To do
 
@@ -138,6 +140,205 @@ tyre pressures, GPS (lat, lon, elevation, heading) and the is_* flags. It does *
   confirmed car facts, app structure, UI conventions, build/test/ship, documents. It replaces
   upstream's EVABRPUploader text. The test emulator is now in the flake: `nix run .#car-emulator`
   (Android 9 AOSP at 1920×720, 160 dpi; the car build installs as the system user — checked).
+- 2026-11-02 — App 2.45.2: Halloween's song banner **waves** (owner: "Can it also be a bit wavy?"): waves run from the bat to the tail, still where the bat holds it and up to 7 units at the tail, and the text follows them (`drawTextOnPath`). Tested: emulator with the throwaway fake session, unit tests, lint. Not tried on the car.
+- 2026-11-02 — App 2.45.1 published (`car-2.45.1`).
+- 2026-11-02 — App 2.45.1: **Halloween's song flies through the sky** (owner: "Instead of taking up screen space on the bottom, can we somehow include the title in the theme itself? ... have text fly through the air"). A bat tows a parchment banner with "♪ title — artist" from left to right across the strip of sky above the sign, behind the moon, one pass about every half minute, again and again while something plays (the title is cut first so the artist stays); the line at the foot of the hill is gone. While a banner flies the view draws about 30 frames a second, as it does while driving. Tested: emulator with the throwaway fake session (banner clear of the sign along the whole pass), unit tests, lint. Not tried on the car.
+- 2026-11-02 — App 2.45.0 published (`car-2.45.0`).
+- 2026-11-02 — App 2.45.0: **now playing on the Overview** (owner: "can we also implement music titles etc in our app?"; display only, Tiles and Halloween first). `NowPlayingWatcher` follows the active media sessions as the music-sources check reads them (`MediaSessionManager`, MEDIA_CONTENT_CONTROL as the system user), with a change listener and a callback per session, so reading costs no call into another app; it never connects to a media browser service (2.42.0) and sends no command. It runs only while the Overview is on screen in Tiles or Halloween with Settings → "Show what's playing" on (**on by default**, `PREF_NOW_PLAYING`). `NowPlaying` (pure, unit-tested) picks the session that plays, the one updated last of several, else the one paused last, passing over sessions without text (Bluetooth's empty one); CarPlay's YouTube titles lose their `[videoID]`; the radio shows its text (the artist field, e.g. "BLIND MELON - NO RAIN") with the station below. Tiles: the empty slot under the battery shows source ("· paused" when paused), title, artist, a cover (the session's picture, or Bluetooth's `ALBUM_ART_URI` file, read small off the main thread) and how far the song is; invisible when nothing plays; the narrow layout has no room and shows none. Halloween: "♪ title — artist" along the foot of the hill, the title cut first. Titles stay on screen: not logged, not sent. Tested: unit tests, lint, emulator with a throwaway build publishing a fake session (CarPlay-like title with ID removed, cover, bar; Halloween line; the switch hides and brings back both). With Halloween chosen the Settings card has two switches more and scrolls further. Not tried on the car: whether the car's sessions, Bluetooth's cover file and the radio text show as in the music-sources checks.
+- 2026-11-02 — App 2.44.0 published (`car-2.44.0`).
+- 2026-11-02 — App 2.44.0: **the pumpkin light follows the bass, and only when switched on** (owner: "more focussed on the bass", "optional via a settings flag"). `MusicPulse` now reads the kick drum's band (40–120 Hz, was 20–250 Hz) and lights only on a jump since the last reading, against the biggest jumps of the last 4 s; a jump under a fifth of that, or under half the bass's average level, lights nothing. So kicks flash, and a held note, a wobbling bass line or a swelling note stay dark (unit tests with made-up patterns). It flares at once and falls in 0.2 s. New switch under the Overview style, shown only for Halloween: "Pumpkin light follows the music" (`PREF_MUSIC_LIGHT`), **off by default**; off, the analyser never starts. Tuned on made-up signals only: no Bluetooth or CarPlay sound report from the car has arrived yet. Next: now playing (title, artist, source) from the media sessions, in its own version. Tested: unit tests, lint, emulator (switch off by default and the analyser thread absent; on, it runs only on the Overview; a throwaway build playing a pulsing test tone: the glow flares with the switch on, and stays exactly still with it off). With Halloween chosen, the Settings card now scrolls a little to reach the tyre unit. Not tried on the car.
+- 2026-11-01 — App 2.43.5 published (`car-2.43.5`).
+- 2026-11-01 — App 2.43.5: **update checks log what happens** (`UpdateNetworkCheck`, `UpdateDiagnosis`; owner: updating from the car fails, "Can we log what happens? Maybe my SIM card has no data left"). Each check on Settings writes to the Logs tab: the networks Android sees (type, in use, internet, validated, roaming), whether the server's name resolves, how a failure happened, in words from its type or status only, and how many reports wait. On a failure it also asks `https://www.gstatic.com/generate_204`, the one request to anyone but the car server, to tell no data from a server that is down. A report goes to a USB stick and, when online, the server (`update-check-*.txt`; only the newest waits, so it cannot push out a recording). A check at start logs only a failure. The update log keeps 40 lines, not 10. An out-of-data SIM would also explain why the Bluetooth and CarPlay sound reports did not arrive; not confirmed. Tested: unit tests, lint, emulator with a fake server (online: the name fails, the internet test says it works; airplane mode: both fail, "none in use"; the real build installs and starts, its check not run there, having no server). Not tried on the car.
+- 2026-11-01 — App 2.43.4 published (`car-2.43.4`).
+- 2026-11-01 — App 2.43.4: **the Halloween pumpkin's light follows the music** (`MusicTap`, `MusicPulse`; owner: "make the light in the pumpkin react to the equalizer/sound of the music"). The bass, 25 times a second off the main thread, drives the glow and brightens the carving on the beat; yellow and green still mean drawing and regenerating, the embers still the power, and no signal leaves the light as it was. It listens only with the app in front, on the Overview, in Halloween. The owner reports the sound check worked with Bluetooth and CarPlay; those two reports never reached the server (why not is unexplained), so their levels are unseen and the pulse's feel is untuned for the car. Tested: unit tests, lint, emulator (a tone already playing when the analyser starts: the carving and glow move with it; no sound: unchanged; the analyser is released on another tab and when the app leaves the front; no crash). Not tried on the car; how it looks there, and its effect on the head unit over a long drive, are unknown.
+- 2026-10-31 — Sound check on the car (2.43.3), radio: `com.saicmotor.radio` playing, `isMusicActive` false, analyser enabled without error and silent for all 10 seconds (peak 0.00, -9600 mB). The audio analyser does not hear the radio. The owner ran Bluetooth and CarPlay too; those reports have not reached the server yet (the outbox sends oldest first and stops at the first failure, retrying while the service runs).
+- 2026-10-31 — App 2.43.3 published (`car-2.43.3`).
+- 2026-10-31 — Music checks from the car: the radio publishes a session while it plays (`com.saicmotor.radio`, 29 October, DAB: TITLE the station, ARTIST the programme text, AUTHOR the band), with `isMusicActive` false, so its sound may not pass through Android's mix and the audio analyser may not hear it. The sound check with the radio playing will tell. CarPlay playing (31 October, 2.43.2) has `isMusicActive` true, like Bluetooth on 28 October. The sound check itself has not run on the car yet: 2.43.3 was not published and those reports came from 2.43.2's music-sources check.
+- 2026-10-31 — App 2.43.3: **sound check** on the Logs tab (`SoundProbe`, `SoundLevels`), asked for before the Halloween pumpkin's light follows the music (owner: "make the light in the pumpkin react to the equalizer/sound of the music"). One tap: 10 seconds of levels from `Visualizer` on session 0 (peak, bass, mid, treble, rms), saved and sent like a recording; no sound kept, no microphone. New in the car build's manifest: RECORD_AUDIO and MODIFY_AUDIO_SETTINGS. Grounds for trying: Bluetooth played with `isMusicActive` true (28 October check), `libCarPlayPlatformAudio.so` uses AudioTrack and no direct PCM. Whether the analyser hears anything on the car is what this is to find out. Tested: unit tests, lint, emulator (silence says nothing was playing; a pulsing 110 Hz + 1 kHz test tone from another app is heard, peak 0.27–0.91, bass strongest, the tone kept playing, no prompt, no crash). Not tried on the car.
+- 2026-10-31 — App 2.43.2 published (`car-2.43.2`).
+- 2026-10-31 — App 2.43.2: Halloween's teeth are triangles hanging from the grin's upper lip, each in the colour of the rib behind it (the right one was the darker orange on the lighter rib; owner: "the color on the right side is off"). Two screenshots redone. Tested: unit tests, lint, emulator with sample values (drawing in panel and full screen, regenerating in full screen) and with no data. Not tried on the car.
+- 2026-10-31 — App 2.43.1 published (`car-2.43.1`).
+- 2026-10-31 — App 2.43.1: Halloween's bats can be seen. They were near-black and small on the darkest part of the sky, and the owner did not spot them; now a moonlit purple-grey with a light edge, a third larger. Two screenshots redone. Tested: unit tests, lint, emulator with sample values (panel and full screen) and with no data (no bats). Not tried on the car.
+- 2026-10-31 — App 2.43.0 published (`car-2.43.0`).
+- 2026-10-31 — App 2.43.0: Overview styles **Día de Muertos** (`MuertosView`) and **Halloween**
+  (`HalloweenView`; owner: "let's design a 'dia de muertos' and a 'halloween' style"), each with
+  its own palette (the papel picado's pink, the pumpkin's orange). Día de Muertos, an ofrenda and
+  kept a celebration: papel picado = battery (one flag per 10 %), calavera with the speed on its
+  forehead, a ring of marigolds = power (turquoise and anticlockwise regenerating), candles =
+  range (one per 50 km), a path of petals = the last two minutes of power. Halloween: a
+  jack-o'-lantern with the speed in its grin, burning yellow or, regenerating, green; an arch of
+  embers = power; a potion flask = battery; a tombstone and bats = range; the hill = the last two
+  minutes of power. What a value lights is `Tally` (pure, unit-tested: an unread value lights
+  nothing). The static scene is drawn once per size into a bitmap (about 4.5 MB while the view is
+  attached), so a frame only draws the readings; flags, flames, bats, bubbles and the ghost move
+  only while the car moves. Tests and lint pass. Emulator with sample values, panel and full
+  screen: normal, 12 % with regeneration, 40 % (the flask's words over the potion's surface); real
+  build with no data: "—" and nothing lit. No crash of the app. Not tried on the car, so the frame
+  rate on the head unit is unmeasured.
+- 2026-10-28 — App 2.42.1 published (`car-2.42.1`).
+- 2026-10-28 — App 2.42.1: **the music-sources check no longer connects to other apps' media
+  services.** In the car, 2.42.0's check (14:26, Bluetooth music playing) made the head unit ask
+  whether to allow access to media (the owner agreed) and **stopped the Bluetooth music**: it
+  connected to every media browser service, and among them the AOSP car radio's
+  (`com.android.car.radio/.RadioService`, which answered "connecting", most likely taking the
+  audio) and the Local Media Player (`com.android.car.media.localmediaplayer`, whose permission
+  request is most likely the question; it may now read media files). My claim that the check only
+  read was wrong: binding another app's service starts it. Now the services are only listed.
+  Nothing lost: the active sessions alone carried everything — **Bluetooth**
+  (`com.android.bluetooth`: title, artist, album, duration, track, cover as a file path, playing)
+  and **CarPlay** (`com.allgo.remoteui.mediabrowserservice`: title, artist, duration, paused) —
+  readable with MEDIA_CONTENT_CONTROL, no connection needed. Services on the car: CarPlay's,
+  Bluetooth A2DP, Local Media Player, the AOSP car radio, SAIC's radio (DAB, "Brillux Radio"),
+  SAIC's USB 1/2 and online media, and SAIC's video browser. Tests and lint pass; not run on the
+  emulator (stopped for low memory; the change only removes code); not tried on the car.
+- 2026-10-28 — App 2.42.0 published (`car-2.42.0`).
+- 2026-10-28 — App 2.42.0: **music-sources check** on the Logs tab (`MediaProbe`,
+  `MediaProbeText`; owner: "is it possible to show playing music in our dashboard as well?", then
+  "yes start the probe"). Before a now-playing display, it finds where the head unit tells what is
+  playing, read only: the players Android's audio service reports (use, app, state), the active
+  media sessions (`MediaSessionManager.getActiveSessions`, MEDIA_CONTENT_CONTROL, which the system
+  user has) with their song, and every media browser service, each connected to, its session read
+  and disconnected. CarPlay's is tried even when not listed:
+  `com.allgo.remoteui.mediabrowserservice/.RemoteUIMediaBrowserService`, which the car's own media
+  library (`com.saicmotor.sdk.media…MediaPlayControlManager` in Allgo's APK) reads CarPlay's title,
+  artist, album and cover from through a plain `MediaBrowser`. Nothing of Allgo's is changed and
+  nothing is played, paused or skipped. The report (`media-probe-YYYYMMDD-HHMMSS.txt`) goes where
+  a recording goes, through the shared `SignalRecorder.saveCopies`: the app, a USB stick, the
+  server (`fetch-logs`). Unit tests for the text; tests and lint pass. Emulator (Android 9): the
+  players are read with their app and state (the system APIs answer the system user), the
+  sessions are readable (none there, no SecurityException), the AOSP music app's browser service
+  connects and is read, CarPlay's (not installed there) is "refused or failed", and the report
+  lands in the outbox. **Not tried on the car.** Unknown until then: whether CarPlay's service
+  lets the app connect, and whether the radio, Bluetooth and USB sources publish a session.
+- 2026-10-28 — First recordings over the server (14:19 and 14:23, app 2.41.0, ACC on, the set
+  speed raised a few times): the server path works, and listening works in the car (249
+  assistance properties, 0 refused, 76 and 81 change events). `0x2160A15B` (`AAD_EPTCCTRGTSPD`)
+  stays 0.0 even while listened to: the car does not fill it. `0x2140A15A` (3/7, a few 0s) and
+  `0x2160A1A3`/`A1A4` (always equal, 1.4–5.3, now and then 0.1–0.2 down) do not move with the
+  key presses. New lead: steering-wheel keys **297** (2× at 14:20:09, 2× at 14:20:12) and **300**
+  (14:20:05, 2× at 14:20:40), the car speeding up 27 → 49 km/h after them; key 3 is Home. The
+  14:23 recording has no key at all. Not confirmed: which buttons these are. Also seen:
+  `0x21401553`–`1556` ≈ 256 are tyre pressures and `0x2140155B`–`155E` (18–24) tyre
+  temperatures, not the set speed.
+- 2026-10-27 — Skill `car-logs` (`.claude/skills/car-logs/SKILL.md`; owner: "can we write a skill for downloading the logs?"): fetch with `fetch-logs` without ever showing the token, what its errors mean, how a recording is laid out, the cuts that find a lead, the leads so far, and that recordings are never committed. Its commands tried on the 08:52 recording.
+- 2026-10-27 — Server 2.9.0 pushed (`sha256:c68837f0e53cfca150644987be535e04d5e999bd4c91064d40973db67235df48`, pinned in `k8s/server.yaml`); app 2.41.0 published (`car-2.41.0`).
+- 2026-10-27 — App 2.41.0, server 2.9.0: **recordings reach the server** (owner: "can we make
+  it so that we can upload the logs to an endpoint in the server, and you can get the logs from
+  there? that way i don't have to carry a usb stick"). A finished signal recording goes to
+  `files/log-outbox` (`LogOutbox`, at most 10 waiting) and is sent at once, gzipped, with the car's
+  token: `PUT /v1/logs/{name}`. Offline, 401 (not paired yet), 404 (a server without logs), 408,
+  429 or 5xx keep it, and the service's tick sends it again, at most every 2 minutes; any other
+  refusal drops it. The Logs tab says "Sent to the server." or how many wait and why. Server
+  (`logs.go`): `LOGS_DIR` on a new 1Gi volume `mg4-server-logs`, the newest 200 files and none
+  older than 180 days, names as the app's only, up to 2 MB sent and 8 MB unpacked, UTF-8 only; the
+  same name replaces itself. Reading (`GET /v1/logs`, `GET /v1/logs/{name}`) takes `LOGS_TOKEN`, a
+  new optional Secret value that must differ from `INGEST_TOKEN`; the car's token cannot read, the
+  read token cannot write. `fetch-logs` in the dev shell fetches the new ones into `logs/`
+  (gitignored, as are the recordings copied into the checkout's top folder), token from
+  `~/.config/nilsmg4/logs-token`. Tested: server unit tests (both tokens, refusals, pruning,
+  config); the real server code in a harness on this machine took the 08:52 recording gzipped as
+  the app sends it (204), refused the car's token for reading (401), and `fetch-logs` brought it
+  back byte for byte, once. The app's own sending could not be pointed at that harness (the app
+  takes https only); on the emulator the recording lands in the outbox and the Logs tab says it
+  waits. Not tried on the car.
+- 2026-10-27 — App 2.40.4 published (`car-2.40.4`).
+- 2026-10-27 — App 2.40.4: **the recorder's listening works on Android 9**. Both recordings
+  from the car (08:49 and 08:52, 2.40.3) said "listening to the assistance properties: not
+  possible": `listenToProperties` looked only for `registerCallback`, Android 10's name; the car's
+  car library (Android 9) has `registerListener(CarPropertyEventListener, int, float)` and
+  `unregisterListener`, as the app's `CarPropertyAdapter` already knew. It now takes either, and
+  unsubscribes property by property (Android 9's one-argument `unregisterListener` removes
+  entries from the list it walks and would leave every other property subscribed). A failure now
+  says why (`EVHardware.listenProblem`: no car service, no way to subscribe, or the exception).
+  Tested with a stand-in manager of Android 9's shape (`PropertyListeningTest`). Correction to
+  2.40.3: the ignition listener it was compared with also looks only for `registerCallback`, so
+  it most likely never subscribes on the car either (it reads the state once at start); left as
+  it is. What the polled part of the two recordings shows of the block: `0x2160A15B` (by name
+  the target speed) 0.0 throughout; `0x2140A15A` between 3 and 7 every few captures;
+  `0x2160A1A3`/`0x2160A1A4` counting up by 0.1; speeds 8–33 km/h. Not tried on the car.
+- 2026-10-27 — App 2.40.3 published (`car-2.40.3`; also carries 2.40.1 and 2.40.2).
+- 2026-10-27 — App 2.40.3: **the signal recorder listens** (owner: "is there really nothing we
+  can do about the readout of the cruise control set point"). The 2.32.0 recording only polled.
+  The head unit's `CarAdvancedAssistedDrivingManager` never polls its 108 `AAD_*` properties: it
+  registers a listener for each (`registerListener(…, 0.0f)`, on change), and a vendor HAL may
+  fill a value from the car network only while someone listens — which would read as the
+  defaults we saw. EVHardware gains `listenToProperties` (read only: the CarPropertyManager's
+  `registerCallback` per admitted property, rate 0 for ON_CHANGE, 1 Hz within limits for
+  CONTINUOUS, one proxy, `unregisterCallback` on close) and `AssistBlock` (global vendor
+  properties `0x21x0A1xx`, which holds all 108 `AAD_*` ids; tested). The recorder subscribes to
+  that block for its 3 minutes; `SignalRecording.event` counts every event and puts value changes
+  on the timeline; the file and the Logs tab list the properties heard, those with changing
+  values first ("heard …"). Emulator (no car service): the recorder notes that listening is not
+  possible, records, saves the new section; no crash. The subscription itself is the same
+  reflection as the ignition listener that works on the car, but untried on the car.
+- 2026-10-27 — App 2.40.2: **the map moves on the GPU** (owner: "is the map screen gpu
+  accelerated? it looks a bit slow on update"). It was hardware-rendered, but every frame (20 a
+  second) recomputed every road point on the main thread, rebuilt all paths, and drew the big
+  roads three times for the glow; and the car jumped with each GPS fix (1 Hz). Now the map is
+  its own view under the Grid (`MapLayerView`, `LAYER_TYPE_HARDWARE`): drawn once into a GPU
+  texture round an anchor and only redrawn when tiles come or go or the car is ~280 layout units
+  (≈230 m) from the anchor; each display frame (`postOnAnimation`, only while that style is on
+  screen and the map shows) sets its translation, pivot and rotation, which the GPU composites.
+  The car glides towards each fix (eased, snaps beyond 200 m), the heading eases; GridView over
+  the map no longer animates itself (only the readings redraw it), the "far roads fainter" sort
+  is a fixed dark gradient towards the top. Layer size on the car about 2500 px square (~25 MB).
+  Measured on the emulator: with SwiftShader (software GPU) old and new both ~57 ms a frame, and
+  with the host's Intel GPU (`-gpu host`) both run at the display rate (~18 ms) — the emulator
+  is too fast to show the car's slowness, so the gain on the head unit is reasoned, not
+  measured. Not tried on the car.
+- 2026-10-27 — App 2.40.1: **an update that downloaded but never reached the installer** (owner:
+  "sometimes … downloads the update but then doesn't start the installer"). The car refuses the
+  installer session ("Not allowed to install non-system apps on internal storage"); only a
+  refusal thrown at once led to the installer screen. A refusal that came back through the
+  session's result was a toast and nothing else. Now any answer but success, the confirmation and
+  the driver's own cancel opens the installer screen with the verified APK (path and session id
+  ride on the result intent; `goAsync` for the copy), a confirmation that cannot be shown does
+  too, and a session silent for 20 s is abandoned for it. Emulator, with a throwaway build whose
+  session bytes were damaged (refused later, status 4 `INSTALL_PARSE_FAILED_NOT_APK`) and which
+  read the update from Downloads: the installer screen opened by itself, Install, now 2.40.1; the
+  update log shows every step. The 20 s watch is untested (no way to make a session stay silent).
+  Not tried on the car. OTA.md updated.
+- 2026-10-27 — App 2.40.0 published (`car-2.40.0`).
+- 2026-10-27 — App 2.40.0: **Grid with map straight from above, full height** (owner: 2.39.2
+  "does not look right"; wanted the map over the whole height and fully top-down). The map is
+  the whole background in map mode: orthographic, heading up, 1.2 layout units per metre (about
+  400 m ahead, 125 m behind, 450 m to each side on the car's screen), the car 150 units above
+  the bottom edge; ground grid every 50 m fixed to the ground; roads from 250 m ahead fainter;
+  the camera, the sky and the floor are gone there. The speed moves to a panel under the gears
+  (120 units), and the battery wall, the clock, the gears and the disc get dark panels. The
+  plain Grid is unchanged. Emulator with the Berlin tiles, both layouts. Not tried on the car.
+- 2026-10-27 — App 2.39.2 published (`car-2.39.2`).
+- 2026-10-27 — App 2.39.2: **Grid with map seen from higher up** (owner: the map looked like a
+  fish-eye; wanted it more top-down). The map has its own pinhole camera now: 45° down, 300 m
+  up, the car on its axis just above the read-outs, the top of the floor about 420 m ahead
+  (scale there ~60 % of the car's, before ~1/20 at 900 m); the floor starts at half height in
+  map mode and the speed is 170 instead of 210 units; the floor's grid becomes a ground grid
+  (a line every 50 m, fixed to the ground, turning with the roads); roads from 250 m ahead
+  fainter; the power disc gets a dark backing over the map. Emulator with the Berlin tiles,
+  both layouts. Not tried on the car.
+- 2026-10-26 — Server 2.8.0 image pushed and pinned in `k8s/server.yaml` by digest
+  `sha256:8b8d94e0562833d196162866b7fdc6910d5dd219f6eb84572d4d5c91b74f7ff1` (checked with skopeo);
+  app 2.39.1 published (`car-2.39.1`). Not applied yet: the owner applies it.
+- 2026-10-26 — App 2.39.1 and server 2.8.0: **the map's roads come from OpenFreeMap, on
+  demand.** In the car, server 2.7.0 logged `overpass answered 502`, `overpass could not be
+  reached`, and the owner saw 429s: the public Overpass limits per IP, and a tile takes it ~40 s
+  while the car gives up after 8 s (`ServerHttp.TIMEOUT_MS`) — the server then cancelled the
+  query, threw the work away, and the car's retries added to the load. Owner's choice: fetch
+  only the tiles the car asks for (a self-hosted Overpass would need a whole region imported).
+  Server: the zoom-14 OpenStreetMap vector tile (OpenMapTiles schema) from the TileJSON at
+  `MAP_TILES_URL` (default OpenFreeMap, free, no key, no limits; its template re-read every 6 h,
+  https only), decoded by our own minimal protobuf/MVT reader (`mvt.go`, the `transportation`
+  layer; classes motorway/trunk, primary/secondary, tertiary, minor), simplified as before. A
+  fetch runs to its end without the car (requests wait ≤ 6 s, then 503 with `Retry-After: 10`),
+  at most two at once, one per tile; tiles kept 30 days in `MAP_CACHE_DIR` (a 1 Gi volume
+  `mg4-server-maps`, pod `fsGroup` 65532) and the last 300 in memory; `OVERPASS_URL` is gone.
+  Tests with an encoded vector tile and a fake tile host (classes, split lines, scaled extent,
+  malformed tiles, gzip from the host, fetched once and kept across a restart, a slow fetch
+  finished for the next try, failures not cached and no tile in the log, http template refused,
+  config). Real: the 9 Berlin tiles in 0.7 s (9–15 KB each). App 2.39.1: "OpenFreeMap ©
+  OpenMapTiles · © OpenStreetMap contributors" on the map, a tile the server did not have yet is
+  asked for again after 15 s (was a minute). Emulator with those tiles: same roads as before.
+  Not tried: the deployed server and the car.
 - 2026-10-26 — Server 2.7.0 image pushed (`git.stinnesbeck.com/nils/mg4-server:2.7.0`, Go 1.27.3,
   govulncheck clean) and pinned in `k8s/server.yaml` by digest
   `sha256:e5da9452a9dbdfabe3340766cc51f18bb1418b2588ab534714550470abe1ce29` (checked with skopeo);

THEMES.md

@@ -1,6 +1,6 @@
 # Overview styles
 
-The Overview can look eighteen ways: pick one under **Settings → Overview style**. Every style shows
+The Overview can look twenty ways: pick one under **Settings → Overview style**. Every style shows
 the same readings (battery, range, power, speed, gear, usage, trip, climate, odometer, time) and
 shows "—" for anything the car did not answer, never a made-up zero.
 
@@ -11,7 +11,7 @@ emulator has no car; on the car the values are live.
 
 **Colours.** Most styles are drawn in the accent colour you pick from the MG4 paints (Settings →
 Accent colour; shown here in Dynamic Red). Retro, Terminal, Grid (with or without the map) and Visor can also show their original
-colours, and Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest and Empire always do; while one of those is shown, the whole app
+colours, and Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest, Empire, Día de Muertos and Halloween always do; while one of those is shown, the whole app
 (navigation, buttons, switches) takes on its colours too.
 
 | Style | Look | Colours |
@@ -34,13 +34,17 @@ colours, and Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest and Empire alway
 | [Quest](#quest) | a fantasy game's interface | own |
 | [Visor](#visor) | a soldier's helmet display | original or accent |
 | [Empire](#empire) | a strategy game's interface | own |
+| [Día de Muertos](#día-de-muertos) | an ofrenda with papel picado and a calavera | own |
+| [Halloween](#halloween) | a jack-o'-lantern on a graveyard hill | own |
 
 ## Tiles
 
 The app's original look, from the design it was forked from: glass cards on OLED black, one tile
 per value, with the averages over the last five minutes and since the start, vehicle info (with
 the lease allowance) and the tyre pressures on a little top view of the car. The most
-information on one screen.
+information on one screen. While something plays over Bluetooth, CarPlay or the radio, the slot
+under the battery shows it: the source, title, artist, a cover when Bluetooth sends one, and how
+far the song is (Settings → "Show what's playing", on by default).
 
 ![Tiles with the navigation](screenshots/themes/tiles-panel.png)
 ![Tiles, full screen](screenshots/themes/tiles.png)
@@ -165,11 +169,13 @@ films' other side.
 
 ## Grid with map
 
-The Grid, with the roads round the car from OpenStreetMap laid on its floor as light lanes, in
+The Grid over a map: the roads round the car from OpenStreetMap (through OpenFreeMap) fill the
-the floor's perspective and turned with the direction you drive: motorways glow brightest, then
+whole screen as light lanes, straight from above and turned with the direction you drive, about
-main roads, then the smaller streets, fading towards the horizon. The car is the chevron on the
+400 m ahead and 450 m to each side: motorways glow brightest, then main roads, then the smaller
+streets, the far ones fainter, over a ground grid every 50 m that turns and slides with them.
+The speed, the battery wall, the power disc and the clock stand on dark panels over the map. The car is the chevron on the
 floor, and between GPS fixes it runs on with the speed. The roads come through the car's own
-server, which fetches them from OpenStreetMap and keeps them (see the README); the car also keeps
+server, which fetches only the map tiles you drive through and keeps them (see the README); the car also keeps
 the last few hundred tiles itself. Without GPS, the server or the roads, the floor says so and
 stays the plain grid. The light-cycle trail makes way for the map here; power stays on the disc.
 Shown with sample values over real roads in central Berlin.
@@ -231,3 +237,39 @@ stats, and a diamond minimap with the odometer and the way to the next age. Belo
 
 ![Empire with the navigation](screenshots/themes/empire-panel.png)
 ![Empire, full screen](screenshots/themes/empire.png)
+
+## Día de Muertos
+
+After the ofrenda, the altar families in Mexico build to welcome their dead back for a visit: a
+celebration, so bright and warm rather than frightening. The papel picado across the top is the
+battery, one cut-paper flag per 10 %, those not lit hanging dark, turning red with "BATTERY LOW"
+below 20 %. The calavera in the middle, a decorated sugar skull with marigolds (cempasúchil) for
+eyes, has the speed on its forehead; the ring of marigolds round it is the power, clockwise while
+drawing, turquoise and anticlockwise while regenerating. The altar's candles are the range, one
+per 50 km. The path of marigold petals along the bottom, which in the tradition leads the visitors
+home, is the last two minutes of power. On the right the clock in a tin frame, P R N D as small
+marigolds, and trip, usage, climate and odometer on the altar cloth. While you drive the flags
+sway and the flames flicker. The app turns the papel picado's pink with it.
+
+![Día de Muertos with the navigation](screenshots/themes/muertos-panel.png)
+![Día de Muertos, full screen](screenshots/themes/muertos.png)
+
+## Halloween
+
+A graveyard hill under a full moon. The jack-o'-lantern has the speed cut into its grin, and its
+carving burns candle yellow while drawing and witch-fire green while regenerating; the arch of
+embers over it is the power, from the left while drawing and from the right while regenerating.
+The potion flask is the battery, red with "BATTERY LOW" blinking below 20 %. The tombstone reads
+the range ("here lies … km"), and the bats are the range too, one per 50 km; P R N D are small
+gravestones, the one engaged lit. The moon holds the clock, a sign hanging from a cobweb has trip,
+usage, climate and odometer, and the hill along the bottom is the last two minutes of power. While
+you drive the bats fly, the potion bubbles and the ghost floats (where there is room for it, as on
+this screen). With "Pumpkin light follows the music" on (Settings, shown with this style; off by
+default) and Bluetooth or CarPlay music playing, the pumpkin's glow flares and its carving
+brightens on each kick drum; the radio cannot be heard, so it burns as usual then. What plays
+(Bluetooth, CarPlay or the radio) flies across the top of the sky on a waving parchment banner that a
+bat tows, behind the moon, again and again while it plays. The app turns the
+pumpkin's orange with it.
+
+![Halloween with the navigation](screenshots/themes/halloween-panel.png)
+![Halloween, full screen](screenshots/themes/halloween.png)

app/build.gradle

@@ -34,8 +34,8 @@ android {
         applicationId "com.stinnesbeck.nilsmg4"
         minSdk 27
         targetSdk 36
-        versionCode 142
+        versionCode 162
-        versionName "2.39.0"
+        versionName "2.45.2"
 
         // Nothing about the server ships in the APK: its URL and ingest token are entered in
         // the app's Server tab (ServerConfig), and the database is only reachable by the server.

app/src/main/java/com/evsuite/abrp/AbrpUploadService.java

@@ -223,6 +223,7 @@ public class AbrpUploadService extends Service {
         consumptionTracker.sample(vehicle);
         chargeSessionTracker.sample(vehicle);
         consumptionCloudClient.syncIfDue(consumptionTracker, chargeSessionTracker, sampleMs);
+        LogOutbox.sendIfDue(this); // recordings the car could not send when they ended
 
         UploadSettings settings = UploadSettings.from(prefs);
         // Live data goes to the server, to ABRP directly, or both; with neither set up there is

app/src/main/java/com/evsuite/abrp/ClusterValues.java

@@ -23,4 +23,6 @@ final class ClusterValues {
     String tyreFl = "—", tyreFr = "—", tyreRl = "—", tyreRr = "—";
     /** Battery power over the last two minutes, oldest first, NaN where unread; null before any. */
     float[] powerTrail;
+    /** What plays ({@link NowPlaying}): the title, null when nothing does or it is off, and the artist or null. */
+    String songTitle, songArtist;
 }

app/src/main/java/com/evsuite/abrp/GridView.java

@@ -23,10 +23,14 @@ import android.os.SystemClock;
  * the trail; the floor stands still when the speed is unread.
  *
  * With a map ("Grid with map", {@link MapRoads}): the roads round the car from OpenStreetMap lie
- * on the floor in its perspective, heading up, the bigger ones glowing brighter, with the car
+ * under everything, heading up, the bigger ones glowing brighter, with the car as a light
- * as a light marker a little way up the floor; between GPS fixes the car's position runs on
+ * marker low on the screen; between GPS fixes the car's position runs on
- * with the speed. The floor's tiles are then 40 m, so they move with the roads, and the trail
+ * with the speed. The map is then the whole background, straight from above (about
- * makes way for the map. Without a fix, a server or the roads, the plain floor with a line
+ * 400 m ahead, 450 m to each side), over a ground grid (a line every 50 m) that turns and slides
+ * with the roads, fading into the dark towards the top. It is its own view under this one
+ * ({@link MapLayerView}): drawn once into a hardware layer and moved and turned by the GPU each
+ * display frame, the car gliding between fixes; the speed, the battery wall, the disc and the clock stand on dark panels over
+ * it, and the trail makes way for the map. Without a fix, a server or the roads, the plain floor with a line
  * saying why.
  *
  * Two palettes: the original cyan, or the chosen accent colour ({@link #setAccentPalette}). A
@@ -39,11 +43,6 @@ final class GridView extends ClusterCanvasView {
     /** Battery segments in the light wall, disc segments, metres per grid tile. */
     private static final int WALL = 20, DISC = 60;
     private static final float TILE_M = 4f;
-    /**
-     * The map: metres per depth step of the floor, the car's depth (just above the read-outs),
-     * the nearest depth drawn, how far ahead, and the depth from which roads are drawn fainter.
-     */
-    private static final float MAP_UNIT_M = 40f, CAR_DEPTH = 1.6f, NEAR = 0.6f, FAR_M = 900f, FADE_DEPTH = 5f;
 
     private final Paint line = new Paint(Paint.ANTI_ALIAS_FLAG);
     private final Paint fill = new Paint(Paint.ANTI_ALIAS_FLAG);
@@ -58,13 +57,10 @@ final class GridView extends ClusterCanvasView {
     private final int accent, accentLight;
     /** Null for the plain Grid. */
     private final MapRoads map;
-    /** Per road class, near and far (from {@link #FADE_DEPTH}). */
+    /** The map under this view (a hardware layer, moved by the GPU); null for the plain Grid. */
-    private final Path[] roads = new Path[RoadTile.CLASSES * 2];
+    private final MapLayerView mapLayer;
-    private float heading = Float.NaN;
+    private final Paint fade = new Paint();
-    /** The pen while a road is added: the last point, and whether it continues from there. */
+    private int fadeFor = -1;
-    private float penX, penY;
-    private boolean penDown;
-    private Path penPath;
 
     private int main, light, dim, alert;
     /** The floor's position within one tile (0..1) and the disc's inner ring angle. */
@@ -79,7 +75,7 @@ final class GridView extends ClusterCanvasView {
     GridView(Context context, MapRoads map) {
         super(context);
         this.map = map;
-        for (int i = 0; i < roads.length; i++) roads[i] = new Path();
+        mapLayer = map == null ? null : new MapLayerView(context, map);
         accent = AccentColor.resolve(context, R.attr.evAccent);
         accentLight = AccentColor.resolve(context, R.attr.evAccentLight);
         line.setStyle(Paint.Style.STROKE);
@@ -95,9 +91,24 @@ final class GridView extends ClusterCanvasView {
         dim = AccentColor.withAlpha(main, 0x40);
         alert = useAccent ? 0xFFFFFFFF : 0xFFFF8A1F;
         skyFor = -1;
+        if (mapLayer != null) mapLayer.setColours(main, light);
         invalidate();
     }
 
+    /** The map layer, for the pane to put under this view; null for the plain Grid. */
+    MapLayerView mapLayer() {
+        return mapLayer;
+    }
+
+    @Override
+    void setValues(ClusterValues values) {
+        super.setValues(values);
+        if (mapLayer != null) {
+            mapLayer.setSpeed(v.speedKmh);
+            mapLayer.kick();
+        }
+    }
+
     @Override
     protected void onDraw(Canvas c) {
         super.onDraw(c);
@@ -105,25 +116,32 @@ final class GridView extends ClusterCanvasView {
         if (w <= 0 || h <= 0) return;
         float u = Math.min(h / 640f, w / 1100f);
         advance();
-        c.drawColor(0xFF000000);
+        // With a map, the map layer underneath is the whole background (this view stays clear
-
+        // there), and the rest stands on dark panels over it.
+        boolean mapShown = mapLayer != null && mapLayer.isShowing();
         float horizon = h * 0.55f;
+        if (mapShown) {
+            drawCar(c, w, h, u);
+        } else {
+            c.drawColor(0xFF000000);
             drawSky(c, w, horizon);
             drawFloor(c, w, h, horizon, u);
-        boolean mapShown = map != null && drawMap(c, w, h, horizon, u);
+        }
         if (map != null && !mapShown) drawMapState(c, w, h, horizon, u);
+        if (mapShown) drawPanels(c, w, horizon, u);
         drawGears(c, w, u);
         drawClock(c, w, u);
-        drawSpeed(c, w, horizon, u);
+        if (mapShown) drawMapSpeed(c, w, u);
+        else drawSpeed(c, w, horizon, u);
         drawWall(c, horizon, u);
-        drawDisc(c, w, u);
+        drawDisc(c, w, mapShown, u);
         if (!mapShown) drawTrail(c, w, h, u);
         drawReadouts(c, w, h, u);
         if (mapShown) drawAttribution(c, w, h, u);
 
         boolean moving = v.speedKmh != null && v.speedKmh > 0.5f;
-        // The map costs more per frame: 20 a second is smooth enough for it.
+        // Over the map only the readings change; the map layer moves itself.
-        keepAnimating(moving, mapShown ? 50 : 33);
+        keepAnimating(moving && !mapShown, 33);
     }
 
     /** Moves the floor by the distance driven since the last frame, and turns the disc. */
@@ -132,8 +150,7 @@ final class GridView extends ClusterCanvasView {
         float dt = lastFrame == 0 ? 0f : Math.min(0.2f, (now - lastFrame) / 1000f);
         lastFrame = now;
         if (v.speedKmh != null && v.speedKmh > 0.5f) {
-            float tile = map != null ? MAP_UNIT_M : TILE_M;
+            floorPhase = (floorPhase + v.speedKmh / 3.6f * dt / TILE_M) % 1f;
-            floorPhase = (floorPhase + v.speedKmh / 3.6f * dt / tile) % 1f;
         }
         if (v.powerKw != null) discTurn = (discTurn + v.powerKw * 3f * dt) % 360f;
     }
@@ -172,118 +189,51 @@ final class GridView extends ClusterCanvasView {
 
     // ---------- Map ----------
 
-    /** The roads round the car on the floor; false when there is nothing to draw. */
+    /** Over the map: the far roads fading into the dark towards the top, and the car. */
-    private boolean drawMap(Canvas c, float w, float h, float horizon, float u) {
+    private void drawCar(Canvas c, float w, float h, float u) {
-        MapRoads.Fix fix = map.fix();
+        float carSx = w / 2f, carSy = h - MapLayerView.CAR_FROM_BOTTOM * u;
-        java.util.Collection<RoadTile> tiles = map.tiles();
+        if (fadeFor != (int) (carSy + h)) {
-        if (fix == null || tiles.isEmpty()) return false;
+            fade.setShader(new LinearGradient(0, 0, 0, carSy, 0xB0000000, 0x00000000, Shader.TileMode.CLAMP));
-        // Heading up: ease round the shorter way; north up until the car has moved.
+            fadeFor = (int) (carSy + h);
-        float target = Float.isNaN(fix.bearing) ? (Float.isNaN(heading) ? 0f : heading) : fix.bearing;
-        if (Float.isNaN(heading)) heading = target;
-        else heading = (heading + (((target - heading) % 360f + 540f) % 360f - 180f) * 0.2f + 360f) % 360f;
-
-        // Between fixes the car runs on with the speed, for at most 2.5 s.
-        double mpu = MapGeometry.metresPerUnit(fix.lat);
-        float ran = 0f;
-        if (v.speedKmh != null && !Float.isNaN(fix.bearing)) {
-            ran = v.speedKmh / 3.6f * Math.min(2.5f, (SystemClock.elapsedRealtime() - fix.elapsedMs) / 1000f);
         }
-        double run = Math.toRadians(Float.isNaN(fix.bearing) ? 0f : fix.bearing);
+        c.drawRect(0, 0, w, carSy, fade);
-        double carX = MapGeometry.worldX(fix.lon) + ran * Math.sin(run) / mpu;
+        // A light-cycle chevron pointing ahead.
-        double carY = MapGeometry.worldY(fix.lat) - ran * Math.cos(run) / mpu;
-
-        float sin = (float) Math.sin(Math.toRadians(heading)), cos = (float) Math.cos(Math.toRadians(heading));
-        float lane = w * 0.09f, depth = h - horizon, vx = w / 2f, m = (float) mpu;
-        double range = FAR_M / mpu;
-        for (Path p : roads) p.reset();
-        for (RoadTile tile : tiles) {
-            double ox = (double) tile.x * MapGeometry.EXTENT - carX, oy = (double) tile.y * MapGeometry.EXTENT - carY;
-            if (ox > range || oy > range || ox + 2 * MapGeometry.EXTENT < -range || oy + 2 * MapGeometry.EXTENT < -range) {
-                continue;
-            }
-            float fx = (float) ox, fy = (float) oy;
-            for (int i = 0; i < tile.points.length; i++) {
-                int[] b = tile.bounds[i];
-                if (fx + b[2] < -range || fx + b[0] > range || fy + b[3] < -range || fy + b[1] > range) continue;
-                int cls = tile.classes[i];
-                int[] pts = tile.points[i];
-                penDown = false;
-                float pa = 0f, pf = 0f;
-                for (int k = 0; k < pts.length; k += 2) {
-                    float east = (fx + pts[k]) * m, north = -(fy + pts[k + 1]) * m;
-                    float fwd = east * sin + north * cos, side = east * cos - north * sin;
-                    if (k > 0) segment(cls, pa, pf, side, fwd, vx, horizon, lane, depth);
-                    pa = side;
-                    pf = fwd;
-                }
-            }
-        }
-        c.save();
-        c.clipRect(0, horizon, w, h);
-        line.setStrokeJoin(Paint.Join.ROUND);
-        line.setStrokeCap(Paint.Cap.ROUND);
-        // Far roads thin and faint, so the horizon stays a line rather than a tangle.
-        for (int cls = RoadTile.CLASSES - 1; cls >= 0; cls--) {
-            line.setColor(AccentColor.withAlpha(cls == 0 ? light : main, cls >= 3 ? 0x30 : 0x50));
-            line.setStrokeWidth((cls == 0 ? 1.6f : 1f) * u);
-            c.drawPath(roads[cls * 2 + 1], line);
-        }
-        line.setColor(AccentColor.withAlpha(main, 0x80));
-        line.setStrokeWidth(1.4f * u);
-        c.drawPath(roads[3 * 2], line);
-        line.setColor(AccentColor.withAlpha(main, 0xC0));
-        line.setStrokeWidth(2f * u);
-        c.drawPath(roads[2 * 2], line);
-        glow(c, roads[2], main, 2.4f * u);
-        glow(c, roads[0], light, 3.2f * u);
-        line.setStrokeJoin(Paint.Join.MITER);
-        line.setStrokeCap(Paint.Cap.SQUARE);
-        c.restore();
-
-        // The car: a light-cycle chevron pointing ahead.
-        float cy = horizon + depth / CAR_DEPTH;
         path.reset();
-        path.moveTo(vx, cy - 16f * u);
+        path.moveTo(carSx, carSy - 18f * u);
-        path.lineTo(vx + 11f * u, cy + 10f * u);
+        path.lineTo(carSx + 12f * u, carSy + 11f * u);
-        path.lineTo(vx, cy + 4f * u);
+        path.lineTo(carSx, carSy + 5f * u);
-        path.lineTo(vx - 11f * u, cy + 10f * u);
+        path.lineTo(carSx - 12f * u, carSy + 11f * u);
         path.close();
         fill.setColor(light);
         c.drawPath(path, fill);
         glow(c, path, light, 1.5f * u);
-        return true;
     }
 
-    /** One stretch of road from (a0, f0) to (a1, f1) in metres (side, ahead), cut at the near edge. */
+    /** Dark panels under the battery wall and the clock, so the map does not run through them. */
-    private void segment(int cls, float a0, float f0, float a1, float f1, float vx, float horizon, float lane,
+    private void drawPanels(Canvas c, float w, float horizon, float u) {
-                         float depth) {
+        chamfer(16f * u, 78f * u, 360f * u, horizon + 86f * u, 14f * u);
-        float d0 = CAR_DEPTH + f0 / MAP_UNIT_M, d1 = CAR_DEPTH + f1 / MAP_UNIT_M;
+        fill.setColor(0xC8000000);
-        Path p = roads[cls * 2 + (Math.min(d0, d1) > FADE_DEPTH ? 1 : 0)];
+        c.drawPath(path, fill);
-        if ((d0 < NEAR && d1 < NEAR) || (f0 > FAR_M && f1 > FAR_M)) {
+        chamfer(w - 210f * u, 12f * u, w - 12f * u, 82f * u, 10f * u);
-            penDown = false;
+        c.drawPath(path, fill);
-            return;
+        // Behind the gears as well.
+        chamfer(w / 2f - 150f * u, 12f * u, w / 2f + 150f * u, 72f * u, 10f * u);
+        c.drawPath(path, fill);
     }
-        boolean cut = false;
+
-        if (d0 < NEAR || d1 < NEAR) {
+    /** The speed over the map: smaller, on a panel under the gears. */
-            float t = (NEAR - d0) / (d1 - d0);
+    private void drawMapSpeed(Canvas c, float w, float u) {
-            float a = a0 + (a1 - a0) * t, d = NEAR;
+        chamfer(w / 2f - 130f * u, 80f * u, w / 2f + 130f * u, 232f * u, 14f * u);
-            if (d0 < NEAR) {
+        fill.setColor(0xC8000000);
-                a0 = a;
+        c.drawPath(path, fill);
-                d0 = d;
+        line.setColor(dim);
-                cut = true;
+        line.setStrokeWidth(1.5f * u);
-            } else {
+        c.drawPath(path, line);
-                a1 = a;
+        text.setTypeface(thin);
-                d1 = d;
+        text.setTextSize(120f * u);
-            }
+        text.setTextAlign(Paint.Align.CENTER);
-        }
+        glowText(c, fmt(v.speedKmh, "%.0f", "—"), w / 2f, 194f * u, light, u);
-        float x0 = vx + a0 / MAP_UNIT_M * lane / d0, y0 = horizon + depth / d0;
+        caption(c, "KM/H", w / 2f, 220f * u, u, Paint.Align.CENTER);
-        float x1 = vx + a1 / MAP_UNIT_M * lane / d1, y1 = horizon + depth / d1;
-        if (!penDown || cut || p != penPath || x0 != penX || y0 != penY) p.moveTo(x0, y0);
-        p.lineTo(x1, y1);
-        penPath = p;
-        penX = x1;
-        penY = y1;
-        penDown = true;
     }
 
     /** Why the map is not there, on the floor. */
@@ -296,14 +246,14 @@ final class GridView extends ClusterCanvasView {
         caption(c, why, w / 2f, horizon + (h - horizon) * 0.2f, u, Paint.Align.CENTER);
     }
 
-    /** OpenStreetMap's licence asks for its name wherever its data is shown. */
+    /** The tiles' and the data's licences ask for their names wherever the map is shown. */
     private void drawAttribution(Canvas c, float w, float h, float u) {
         text.setTypeface(label);
         text.setTextSize(12f * u);
         text.setTextAlign(Paint.Align.RIGHT);
         text.setStyle(Paint.Style.FILL);
         text.setColor(dim);
-        c.drawText("© OpenStreetMap contributors", w - 26f * u, h - 80f * u, text);
+        c.drawText("OpenFreeMap © OpenMapTiles · © OpenStreetMap contributors", w - 26f * u, h - 80f * u, text);
     }
 
     // ---------- Top ----------
@@ -393,8 +343,13 @@ final class GridView extends ClusterCanvasView {
     // ---------- Power disc ----------
 
     /** Zero at the top, −50 kW a quarter turn anticlockwise, 150 kW three quarters clockwise. */
-    private void drawDisc(Canvas c, float w, float u) {
+    private void drawDisc(Canvas c, float w, boolean overMap, float u) {
         float cx = w - 170f * u, cy = 238f * u, outer = 132f * u, ring = 22f * u;
+        if (overMap) {
+            // The map runs under the disc: a dark backing keeps it readable.
+            fill.setColor(0xD0000000);
+            c.drawCircle(cx, cy, outer + 16f * u, fill);
+        }
         line.setColor(dim);
         line.setStrokeWidth(1.5f * u);
         c.drawCircle(cx, cy, outer + 10f * u, line);

app/src/main/java/com/evsuite/abrp/HalloweenView.java

@@ -0,0 +1,648 @@
+package com.evsuite.abrp;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.LinearGradient;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.graphics.PathMeasure;
+import android.graphics.RadialGradient;
+import android.graphics.RectF;
+import android.graphics.Shader;
+import android.graphics.Typeface;
+import android.os.SystemClock;
+
+import java.util.Locale;
+
+/**
+ * The Halloween Overview style: a graveyard hill under a full moon.
+ *
+ * In the middle a jack-o'-lantern with the speed cut into its grin; its carving burns candle yellow
+ * while drawing and witch-fire green while regenerating, and the arch of embers over it is the
+ * power, left to right while drawing, green and right to left while regenerating. On the left a
+ * potion flask: the battery, red with "BATTERY LOW" blinking below 20 %, under a sign hanging from
+ * a cobweb with trip, usage, climate and odometer. On the right the moon holds the clock, and a
+ * tombstone reads the range ("here lies … km"); P R N D are four small gravestones, the one engaged
+ * lit. The bats are the range too, one per 50 km. The hill along the bottom is the last two minutes
+ * of power, rising with it, in orange or, where it regenerated, green. Unread values show "—" and
+ * light nothing. With music playing, the pumpkin's glow swells and its carving brightens on the
+ * beat ({@link MusicTap}); colours and the embers keep their meaning, and with no music it burns as
+ * before. What plays flies across the sky on a banner a bat tows ({@link NowPlaying}).
+ *
+ * The night sky is drawn once into a bitmap per size; only the rest goes over it. Bats, bubbles and
+ * the ghost move (about 30 frames a second) only while the car moves and the view is on screen;
+ * the light's pulse keeps it drawing while there is one.
+ */
+final class HalloweenView extends ClusterCanvasView {
+
+    private static final int EMBERS = 25, BATS = 8;
+    private static final int SKY_TOP = 0xFF0B0620, SKY_LOW = 0xFF2A1140, HILL = 0xFF0A0612;
+    private static final int PUMPKIN = 0xFFF2760F, PUMPKIN_DARK = 0xFFB84A06, PUMPKIN_LIT = 0xFFFF9A2E;
+    private static final int CANDLE = 0xFFFFD84A, FIRE = 0xFF6BFF5A, RED = 0xFFFF3B30, STONE = 0xFF6C6A78;
+    private static final int STONE_DARK = 0xFF3E3C4A, MOON = 0xFFF4E9B8, MOON_SHADE = 0xFFD8C98C;
+    private static final int POTION = 0xFF7BF03A, GLASS = 0xFFB9D8D0, BONE = 0xFFF2EAD8, ORANGE = 0xFFFF8C1A;
+    private static final int STEM = 0xFF4E7A2B, WOOD = 0xFF2E1B10, INK = 0xFF140A08;
+    private static final int BAT = 0xFF6F6390, BAT_EDGE = 0xFFD6CCEA;
+
+    private final Paint fill = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint line = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint text = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint image = new Paint(Paint.FILTER_BITMAP_FLAG);
+    private final Paint glow = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Path path = new Path();
+    private final Path baseline = new Path();
+    private final PathMeasure measure = new PathMeasure();
+    private final RectF r = new RectF();
+    private final Typeface serif = Typeface.create("serif", Typeface.BOLD);
+    private final Typeface face = Typeface.create("sans-serif-condensed", Typeface.BOLD);
+    private final Typeface thin = Typeface.create("sans-serif-condensed", Typeface.NORMAL);
+
+    private Bitmap sky;
+    private int skyW, skyH;
+    private float time;
+    private long lastFrame;
+    private MusicTap music;
+
+    HalloweenView(Context context) {
+        super(context);
+        line.setStyle(Paint.Style.STROKE);
+        line.setStrokeCap(Paint.Cap.ROUND);
+    }
+
+    /** Where the pumpkin's light hears the music; without it, the light does not follow any. */
+    void setMusic(MusicTap tap) {
+        music = tap;
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+        sky = null;
+        skyW = 0;
+    }
+
+    @Override
+    protected void onDraw(Canvas c) {
+        super.onDraw(c);
+        int w = getWidth(), h = getHeight();
+        if (w <= 0 || h <= 0) return;
+        float u = Math.min(h / 640f, w / 1100f);
+        boolean moving = v.speedKmh != null && v.speedKmh > 0.5f;
+        if (moving) {
+            long now = SystemClock.uptimeMillis();
+            time += lastFrame == 0 ? 0f : Math.min(0.2f, (now - lastFrame) / 1000f);
+            lastFrame = now;
+        } else {
+            lastFrame = 0;
+        }
+        if (sky == null || skyW != w || skyH != h) buildSky(w, h, u);
+        c.drawBitmap(sky, 0, 0, image);
+        drawBats(c, w, u);
+        boolean song = drawSong(c, w, u);
+        drawMoon(c, w, u);
+        drawGhost(c, w, u);
+        drawHill(c, w, h, u);
+        drawEmbers(c, w, u);
+        float pulse = music == null ? 0f : music.pulse();
+        drawPumpkin(c, w, u, pulse);
+        drawSign(c, u);
+        drawFlask(c, u);
+        drawTombstone(c, w, u);
+        drawGears(c, w, u);
+        keepAnimating(moving || pulse > 0f || song, 33);
+    }
+
+    private void label(Canvas c, String s, float x, float y, float size, int colour, Typeface tf, Paint.Align a) {
+        text.setTypeface(tf);
+        text.setTextSize(size);
+        text.setTextAlign(a);
+        text.setColor(colour);
+        c.drawText(s, x, y, text);
+    }
+
+    private boolean regen() {
+        return v.powerKw != null && v.powerKw < -0.05f;
+    }
+
+    // ---------- Sky ----------
+
+    private void buildSky(int w, int h, float u) {
+        sky = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
+        skyW = w;
+        skyH = h;
+        Canvas c = new Canvas(sky);
+        Paint p = new Paint();
+        p.setShader(new LinearGradient(0, 0, 0, h, new int[] { SKY_TOP, SKY_LOW, 0xFF4A1A3A },
+                new float[] { 0f, 0.7f, 1f }, Shader.TileMode.CLAMP));
+        c.drawRect(0, 0, w, h, p);
+        Paint star = new Paint(Paint.ANTI_ALIAS_FLAG);
+        star.setColor(0x80FFFFFF);
+        for (int i = 0; i < 90; i++) {
+            float x = ((i * 191 + 17) % 1009) / 1009f * w, y = ((i * 83 + 5) % 421) * u;
+            c.drawCircle(x, y, (i % 4 == 0 ? 1.7f : 0.9f) * u, star);
+        }
+        // Bare trees in the distance.
+        tree(c, w * 0.235f, 590f * u, 150f * u, u);
+        tree(c, w * 0.745f, 590f * u, 118f * u, u);
+    }
+
+    /** A bare tree: a trunk and branches that fork twice. */
+    private void tree(Canvas c, float x, float y, float tall, float u) {
+        Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
+        p.setStyle(Paint.Style.STROKE);
+        p.setStrokeCap(Paint.Cap.ROUND);
+        p.setColor(0xFF160B20);
+        branch(c, p, x, y, -90f, tall * 0.5f, 7f * u, 4);
+    }
+
+    private void branch(Canvas c, Paint p, float x, float y, float deg, float len, float width, int depth) {
+        double a = Math.toRadians(deg);
+        float nx = x + (float) Math.cos(a) * len, ny = y + (float) Math.sin(a) * len;
+        p.setStrokeWidth(width);
+        c.drawLine(x, y, nx, ny, p);
+        if (depth == 0) return;
+        branch(c, p, nx, ny, deg - 24f - depth * 3f, len * 0.68f, width * 0.65f, depth - 1);
+        branch(c, p, nx, ny, deg + 28f - depth * 2f, len * 0.62f, width * 0.65f, depth - 1);
+    }
+
+    // ---------- Moon and clock ----------
+
+    private void drawMoon(Canvas c, int w, float u) {
+        float rad = 74f * u, cx = w - 100f * u - rad * 0.2f, cy = 96f * u;
+        glow.setShader(new RadialGradient(cx, cy, rad * 2.2f, new int[] { 0x55F4E9B8, 0x00F4E9B8 }, null,
+                Shader.TileMode.CLAMP));
+        c.drawCircle(cx, cy, rad * 2.2f, glow);
+        fill.setColor(MOON);
+        c.drawCircle(cx, cy, rad, fill);
+        fill.setColor(MOON_SHADE);
+        c.drawCircle(cx - 42f * u, cy - 34f * u, 12f * u, fill);
+        c.drawCircle(cx + 40f * u, cy + 38f * u, 16f * u, fill);
+        c.drawCircle(cx + 46f * u, cy - 26f * u, 7f * u, fill);
+        c.drawCircle(cx - 30f * u, cy + 44f * u, 8f * u, fill);
+        label(c, v.clock.isEmpty() ? "—" : v.clock, cx, cy + 17f * u, 50f * u, INK, serif, Paint.Align.CENTER);
+    }
+
+    // ---------- Bats: the range ----------
+
+    private void drawBats(Canvas c, int w, float u) {
+        int lit = Tally.lit(v.rangeKm, 50f, BATS);
+        float cx = w / 2f;
+        for (int i = 0; i < lit; i++) {
+            // Each its own lane high in the sky, clear of the pumpkin's middle.
+            float lane = (40f + (i * 37) % 70) * u;
+            float span = w * 0.92f, speed = (26f + i * 5f) * u;
+            float x = ((i * 0.13f * span + time * speed) % span) + w * 0.04f;
+            float y = lane + (float) Math.sin(time * 2f + i) * 8f * u;
+            if (Math.abs(x - cx) < 60f * u) y -= 10f * u;
+            bat(c, x, y, (i % 2 == 0 ? 20f : 16f) * u, (float) Math.sin(time * 14f + i * 2f), u);
+        }
+    }
+
+    private void bat(Canvas c, float x, float y, float s, float flap, float u) {
+        float tip = -s * 0.5f * flap;
+        path.reset();
+        path.moveTo(x, y - s * 0.3f);
+        path.quadTo(x + s * 0.6f, y - s * 0.7f + tip, x + s * 1.5f, y - s * 0.3f + tip);
+        path.quadTo(x + s * 1.1f, y + s * 0.05f, x + s * 0.9f, y + s * 0.35f);
+        path.quadTo(x + s * 0.6f, y + s * 0.05f, x + s * 0.35f, y + s * 0.4f);
+        path.quadTo(x + s * 0.15f, y + s * 0.15f, x, y + s * 0.5f);
+        path.quadTo(x - s * 0.15f, y + s * 0.15f, x - s * 0.35f, y + s * 0.4f);
+        path.quadTo(x - s * 0.6f, y + s * 0.05f, x - s * 0.9f, y + s * 0.35f);
+        path.quadTo(x - s * 1.1f, y + s * 0.05f, x - s * 1.5f, y - s * 0.3f + tip);
+        path.quadTo(x - s * 0.6f, y - s * 0.7f + tip, x, y - s * 0.3f);
+        path.close();
+        // Lit by the moon: black would vanish in the night sky.
+        fill.setColor(BAT);
+        c.drawPath(path, fill);
+        line.setColor(BAT_EDGE);
+        line.setStrokeWidth(1.5f * u);
+        c.drawPath(path, line);
+    }
+
+    // ---------- Ghost: only where there is room ----------
+
+    private void drawGhost(Canvas c, int w, float u) {
+        if (w / u < 1400f) return;
+        float x = (w / 2f + 272f * u + w - 290f * u) / 2f, y = 330f * u + (float) Math.sin(time * 1.4f) * 12f * u, s = 34f * u;
+        path.reset();
+        path.moveTo(x - s, y + s * 1.5f);
+        path.lineTo(x - s, y);
+        path.cubicTo(x - s, y - s * 1.4f, x + s, y - s * 1.4f, x + s, y);
+        path.lineTo(x + s, y + s * 1.5f);
+        float wob = (float) Math.sin(time * 3f) * s * 0.12f;
+        path.quadTo(x + s * 0.66f, y + s * 1.1f + wob, x + s * 0.33f, y + s * 1.5f);
+        path.quadTo(x, y + s * 1.1f - wob, x - s * 0.33f, y + s * 1.5f);
+        path.quadTo(x - s * 0.66f, y + s * 1.1f + wob, x - s, y + s * 1.5f);
+        path.close();
+        fill.setColor(0xB8F0F4FF);
+        c.drawPath(path, fill);
+        fill.setColor(0xFF1A1030);
+        c.drawCircle(x - s * 0.34f, y - s * 0.2f, s * 0.14f, fill);
+        c.drawCircle(x + s * 0.34f, y - s * 0.2f, s * 0.14f, fill);
+        r.set(x - s * 0.14f, y + s * 0.08f, x + s * 0.14f, y + s * 0.44f);
+        c.drawOval(r, fill);
+    }
+
+    // ---------- The hill: the last two minutes of power ----------
+
+    private void drawHill(Canvas c, int w, int h, float u) {
+        float base = h - 44f * u, amp = 36f * u;
+        float[] trail = v.powerTrail;
+        path.reset();
+        path.moveTo(0, h);
+        int n = trail == null ? 0 : trail.length;
+        if (n == 0) {
+            path.lineTo(0, base);
+            path.lineTo(w, base);
+        } else {
+            for (int i = 0; i < n; i++) {
+                float p = trail[i];
+                float height = Float.isNaN(p) ? 0f : Math.min(1f, Math.abs(p) / (p < 0 ? 40f : 60f));
+                path.lineTo(i / (n - 1f) * w, base - height * amp);
+            }
+        }
+        path.lineTo(w, h);
+        path.close();
+        fill.setColor(HILL);
+        c.drawPath(path, fill);
+        // The ridge line, each stretch in the colour of what the car was doing then.
+        if (n > 1) {
+            line.setStrokeWidth(3f * u);
+            for (int i = 1; i < n; i++) {
+                float a = trail[i - 1], b = trail[i];
+                if (Float.isNaN(a) || Float.isNaN(b)) continue;
+                float ha = Math.min(1f, Math.abs(a) / (a < 0 ? 40f : 60f));
+                float hb = Math.min(1f, Math.abs(b) / (b < 0 ? 40f : 60f));
+                line.setColor(b < 0 ? FIRE : ORANGE);
+                c.drawLine((i - 1f) / (n - 1f) * w, base - ha * amp, i / (n - 1f) * w, base - hb * amp, line);
+            }
+        }
+    }
+
+    // ---------- What plays: a bat tows it across the sky on a banner ----------
+
+    /**
+     * A bat pulls a waving parchment banner with the song from left to right, high in the sky, behind the
+     * sign and the moon, again and again while something plays. Returns whether it is drawn, so
+     * the view keeps animating for it.
+     */
+    private boolean drawSong(Canvas c, int w, float u) {
+        if (v.songTitle == null) return false;
+        text.setTypeface(face);
+        text.setTextSize(19f * u);
+        float room = Math.min(560f * u, w * 0.45f);
+        String artist = v.songArtist == null ? "" : " — " + cut(v.songArtist, room / 2.5f);
+        // A long title gives way, so the artist stays.
+        String s = "♪ " + cut(v.songTitle, room - text.measureText("♪ " + artist)) + artist;
+        float t = SystemClock.uptimeMillis() / 1000f;
+        float bw = text.measureText(s) + 40f * u, bh = 30f * u, tow = 56f * u;
+        // One pass takes about half a minute; then it comes round again from the left.
+        float travel = w + bw + tow + 80f * u;
+        float bx = (t * 70f * u) % travel - bw - tow - 40f * u;
+        // In the strip of sky above the sign, clear of it.
+        float yc = 34f * u + (float) Math.sin(t * 1.3f) * 4f * u;
+        float top = yc - bh / 2f, bottom = yc + bh / 2f, right = bx + bw, notch = 12f * u;
+        // The ribbon, waving in the wind: still where the bat holds it, rippling more towards its
+        // tail, which is cut as a swallowtail. The text follows the waves.
+        int steps = Math.max(8, Math.round(bw / (12f * u)));
+        path.reset();
+        for (int i = 0; i <= steps; i++) {
+            float x = right - bw * i / steps;
+            if (i == 0) path.moveTo(x, top + wave(x, right, bw, t, u));
+            else path.lineTo(x, top + wave(x, right, bw, t, u));
+        }
+        path.lineTo(bx + notch, yc + wave(bx + notch, right, bw, t, u));
+        for (int i = steps; i >= 0; i--) path.lineTo(right - bw * i / steps, bottom + wave(right - bw * i / steps, right, bw, t, u));
+        path.close();
+        fill.setColor(BONE);
+        c.drawPath(path, fill);
+        line.setColor(0xFF8A6A3A);
+        line.setStrokeWidth(2f * u);
+        c.drawPath(path, line);
+        baseline.reset();
+        for (int i = 0; i <= steps; i++) {
+            float x = bx + notch + (bw - notch) * i / steps;
+            if (i == 0) baseline.moveTo(x, yc + wave(x, right, bw, t, u));
+            else baseline.lineTo(x, yc + wave(x, right, bw, t, u));
+        }
+        measure.setPath(baseline, false);
+        text.setColor(INK);
+        text.setTextAlign(Paint.Align.LEFT);
+        c.drawTextOnPath(s, baseline, Math.max(0f, (measure.getLength() - text.measureText(s)) / 2f), 7f * u, text);
+        // The tow lines, and the bat at their end.
+        float batX = right + tow, batY = yc - 10f * u;
+        line.setColor(BAT_EDGE);
+        line.setStrokeWidth(1.5f * u);
+        c.drawLine(right, top + 3f * u, batX, batY + 6f * u, line);
+        c.drawLine(right, bottom - 3f * u, batX, batY + 6f * u, line);
+        bat(c, batX, batY, 26f * u, (float) Math.sin(t * 12f), u);
+        return true;
+    }
+
+    /**
+     * How far the banner bends at {@code x}: nothing at the bat's end ({@code right}), up to 7 units
+     * at the tail, in waves that run from the bat to the tail.
+     */
+    private static float wave(float x, float right, float bw, float t, float u) {
+        float along = right - x;
+        return 7f * u * (along / bw) * (float) Math.sin(along / (170f * u) * 2f * Math.PI - t * 5f);
+    }
+
+    /** {@code s} cut with "…" to fit {@code room} in the text paint as set. */
+    private String cut(String s, float room) {
+        if (text.measureText(s) <= room) return s;
+        int fits = text.breakText(s, true, Math.max(0f, room - text.measureText("…")), null);
+        return s.substring(0, Math.max(0, fits)).trim() + "…";
+    }
+
+    // ---------- The arch of embers: the power ----------
+
+    private void drawEmbers(Canvas c, int w, float u) {
+        float cx = w / 2f, cy = 348f * u, radX = 272f * u, radY = 244f * u;
+        int lit = Tally.ofPower(v.powerKw, 150f, 50f, EMBERS);
+        boolean regen = v.powerKw != null && v.powerKw < 0f;
+        for (int i = 0; i < EMBERS; i++) {
+            // Left to right over the top; regeneration comes back from the right.
+            int k = regen ? EMBERS - 1 - i : i;
+            double a = Math.PI + Math.PI * k / (EMBERS - 1);
+            float x = cx + (float) Math.cos(a) * radX, y = cy + (float) Math.sin(a) * radY;
+            boolean on = i < lit;
+            if (on) {
+                fill.setColor(AccentColor.withAlpha(regen ? FIRE : ORANGE, 0x44));
+                c.drawCircle(x, y, 15f * u, fill);
+            }
+            fill.setColor(on ? (regen ? FIRE : CANDLE) : 0x38FFFFFF);
+            c.drawCircle(x, y, 7.5f * u, fill);
+        }
+    }
+
+    // ---------- The jack-o'-lantern: the speed ----------
+
+    private void drawPumpkin(Canvas c, int w, float u, float pulse) {
+        float cx = w / 2f, cy = 348f * u, rx = 200f * u, ry = 158f * u;
+        boolean regen = regen();
+        // The carving brightens on the beat, gently, and stays yellow or green.
+        int burn = brighter(regen ? FIRE : CANDLE, pulse * 0.35f);
+        // The light it throws, stronger the more power, swelling with the music.
+        float share = v.powerKw == null ? 0f : Math.min(1f, Math.abs(v.powerKw) / 80f);
+        float reach = rx * (1.6f + pulse * 0.2f);
+        glow.setShader(new RadialGradient(cx, cy, reach,
+                new int[] { AccentColor.withAlpha(regen ? FIRE : ORANGE, 0x30 + (int) (share * 0x50) + (int) (pulse * 0x60)),
+                        AccentColor.withAlpha(regen ? FIRE : ORANGE, 0) }, null, Shader.TileMode.CLAMP));
+        c.drawCircle(cx, cy, reach, glow);
+        // The stem.
+        path.reset();
+        path.moveTo(cx - 22f * u, cy - ry + 12f * u);
+        path.quadTo(cx - 14f * u, cy - ry - 26f * u, cx + 14f * u, cy - ry - 44f * u);
+        path.lineTo(cx + 34f * u, cy - ry - 30f * u);
+        path.quadTo(cx + 14f * u, cy - ry - 12f * u, cx + 22f * u, cy - ry + 12f * u);
+        path.close();
+        fill.setColor(STEM);
+        c.drawPath(path, fill);
+        // The ribs, outermost first, overlapping.
+        float[][] ribs = { { -0.70f, 0.42f }, { 0.70f, 0.42f }, { -0.40f, 0.48f }, { 0.40f, 0.48f }, { 0f, 0.50f } };
+        for (int i = 0; i < ribs.length; i++) {
+            float rcx = cx + ribs[i][0] * rx, half = ribs[i][1] * rx;
+            r.set(rcx - half, cy - ry * (i < 2 ? 0.86f : 0.98f), rcx + half, cy + ry * (i < 2 ? 0.86f : 0.98f));
+            fill.setColor(i % 2 == 0 ? PUMPKIN : PUMPKIN_LIT);
+            if (i == ribs.length - 1) fill.setColor(PUMPKIN);
+            c.drawOval(r, fill);
+            line.setColor(PUMPKIN_DARK);
+            line.setStrokeWidth(2.5f * u);
+            c.drawOval(r, line);
+        }
+        // Eyes and nose: triangles, burning.
+        triangle(c, cx - 88f * u, cy - 92f * u, cx - 34f * u, cy - 28f * u, cx - 128f * u, cy - 28f * u, burn, u);
+        triangle(c, cx + 88f * u, cy - 92f * u, cx + 128f * u, cy - 28f * u, cx + 34f * u, cy - 28f * u, burn, u);
+        triangle(c, cx, cy - 28f * u, cx + 19f * u, cy + 4f * u, cx - 19f * u, cy + 4f * u, burn, u);
+        // The grin, with the speed cut dark into its light.
+        float gt = cy + 8f * u, gb = cy + 122f * u, gw = 156f * u;
+        path.reset();
+        path.moveTo(cx - gw, gt);
+        path.quadTo(cx, gt + 26f * u, cx + gw, gt);
+        path.quadTo(cx + gw * 0.82f, gb, cx, gb);
+        path.quadTo(cx - gw * 0.82f, gb, cx - gw, gt);
+        path.close();
+        fill.setColor(0xFF4A1F04);
+        c.drawPath(path, fill);
+        c.save();
+        c.scale(0.965f, 0.93f, cx, (gt + gb) / 2f);
+        fill.setColor(burn);
+        c.drawPath(path, fill);
+        c.restore();
+        // Two teeth at the grin's corners, clear of the digits, each the colour of the rib it hangs from.
+        tooth(c, cx, -120f * u, gw, gt, 26f * u, 17f * u, gt + 40f * u, PUMPKIN, u);
+        tooth(c, cx, 120f * u, gw, gt, 26f * u, 17f * u, gt + 40f * u, PUMPKIN_LIT, u);
+        label(c, fmt(v.speedKmh, "%.0f", "—"), cx, gb - 18f * u, 92f * u, INK, serif, Paint.Align.CENTER);
+        label(c, "KM/H", cx + 80f * u, cy + 64f * u, 16f * u, INK, face, Paint.Align.LEFT);
+        // The power under the pumpkin, above the ridge.
+        String power = v.powerKw == null ? "— kW" : String.format(Locale.US, regen ? "+%.1f kW" : "%.1f kW",
+                Math.abs(v.powerKw));
+        label(c, power, cx, cy + ry + 44f * u, 34f * u, regen ? FIRE : BONE, face, Paint.Align.CENTER);
+    }
+
+    /** The colour moved {@code share} of the way to white. */
+    private static int brighter(int colour, float share) {
+        int r = (colour >> 16) & 0xFF, g = (colour >> 8) & 0xFF, b = colour & 0xFF;
+        return 0xFF000000 | (r + (int) ((255 - r) * share)) << 16 | (g + (int) ((255 - g) * share)) << 8
+                | (b + (int) ((255 - b) * share));
+    }
+
+    private void triangle(Canvas c, float x1, float y1, float x2, float y2, float x3, float y3, int burn, float u) {
+        path.reset();
+        path.moveTo(x1, y1);
+        path.lineTo(x2, y2);
+        path.lineTo(x3, y3);
+        path.close();
+        fill.setColor(burn);
+        c.drawPath(path, fill);
+        line.setColor(0xFF4A1F04);
+        line.setStrokeWidth(4f * u);
+        c.drawPath(path, line);
+    }
+
+    /** A triangle hanging from the grin's upper lip (a curve sagging by {@code sag}) to {@code tipY}. */
+    private void tooth(Canvas c, float cx, float dx, float gw, float gt, float sag, float halfW, float tipY, int colour, float u) {
+        float left = lip(dx - halfW, gw, gt, sag), right = lip(dx + halfW, gw, gt, sag);
+        path.reset();
+        // A little above the lip, so none of its dark edge shows across the tooth's root.
+        path.moveTo(cx + dx - halfW, left - 1.5f * u);
+        path.lineTo(cx + dx + halfW, right - 1.5f * u);
+        path.lineTo(cx + dx, tipY);
+        path.close();
+        fill.setColor(colour);
+        c.drawPath(path, fill);
+        line.setColor(0xFF4A1F04);
+        line.setStrokeWidth(3f * u);
+        c.drawLine(cx + dx - halfW, left + 2f * u, cx + dx, tipY, line);
+        c.drawLine(cx + dx + halfW, right + 2f * u, cx + dx, tipY, line);
+    }
+
+    /** The height of the grin's upper lip {@code dx} from the middle. */
+    private static float lip(float dx, float gw, float gt, float sag) {
+        float t = (gw - Math.abs(dx)) / (2f * gw);
+        return gt + 2f * t * (1f - t) * sag;
+    }
+
+    // ---------- Left: the sign under the cobweb ----------
+
+    private void drawSign(Canvas c, float u) {
+        // The cobweb in the corner.
+        float cs = 150f * u;
+        line.setColor(0x70E8E8F4);
+        line.setStrokeWidth(1.2f * u);
+        for (int i = 0; i <= 5; i++) {
+            double a = Math.PI / 2 * i / 5;
+            c.drawLine(0, 0, (float) Math.cos(a) * cs, (float) Math.sin(a) * cs, line);
+        }
+        for (int ring = 1; ring <= 4; ring++) {
+            float d = cs * ring / 4f;
+            path.reset();
+            for (int i = 0; i <= 5; i++) {
+                double a = Math.PI / 2 * i / 5;
+                float x = (float) Math.cos(a) * d, y = (float) Math.sin(a) * d;
+                if (i == 0) {
+                    path.moveTo(x, y);
+                } else {
+                    double mid = Math.PI / 2 * (i - 0.5) / 5;
+                    path.quadTo((float) Math.cos(mid) * d * 0.86f, (float) Math.sin(mid) * d * 0.86f, x, y);
+                }
+            }
+            c.drawPath(path, line);
+        }
+        // The sign, on two threads.
+        float l = 28f * u, rr = l + 300f * u, t = 50f * u, b = 244f * u;
+        line.setColor(0xA0E8E8F4);
+        c.drawLine(l + 60f * u, 0, l + 60f * u, t, line);
+        c.drawLine(rr - 60f * u, 0, rr - 60f * u, t, line);
+        r.set(l, t, rr, b);
+        fill.setColor(WOOD);
+        c.drawRoundRect(r, 8f * u, 8f * u, fill);
+        line.setColor(0xFF6B4226);
+        line.setStrokeWidth(2.5f * u);
+        c.drawRoundRect(r, 8f * u, 8f * u, line);
+        String[][] rows = {
+                { "TRIP", fmt(v.tripKm, "%.1f km", "—") },
+                { "5 MIN", fmt(v.usage5Min, "%.1f kWh/100", "—") },
+                { "SINCE START", fmt(v.usageTrip, "%.1f kWh/100", "—") },
+                { "CLIMATE", fmt(v.climateCelsius, "%.0f °C", "—") },
+                { "ODOMETER", fmt(v.odometerKm, "%,.0f km", "—") },
+        };
+        for (int i = 0; i < rows.length; i++) {
+            float y = t + (36f + i * 34f) * u;
+            label(c, rows[i][0], l + 16f * u, y, 19f * u, ORANGE, thin, Paint.Align.LEFT);
+            label(c, rows[i][1], rr - 16f * u, y, 23f * u, BONE, face, Paint.Align.RIGHT);
+        }
+    }
+
+    // ---------- The potion flask: the battery ----------
+
+    private void drawFlask(Canvas c, float u) {
+        float rad = 104f * u, cx = 28f * u + 150f * u, cy = 452f * u;
+        boolean low = v.socPercent != null && v.socPercent < 20f;
+        boolean blinkOn = (SystemClock.uptimeMillis() / 500) % 2 == 0;
+        int colour = low ? RED : POTION;
+        float neckW = 34f * u, neckTop = cy - rad - 42f * u;
+        // The glass shape: a round belly and a neck.
+        path.reset();
+        path.addCircle(cx, cy, rad, Path.Direction.CW);
+        r.set(cx - neckW, neckTop, cx + neckW, cy - rad + 16f * u);
+        path.addRect(r, Path.Direction.CW);
+        fill.setColor(0x38B9D8D0);
+        c.drawPath(path, fill);
+        // The potion: as high as the battery is full, across the belly only.
+        if (v.socPercent != null) {
+            float share = Math.max(0f, Math.min(1f, v.socPercent / 100f));
+            float level = cy + rad - share * 2f * rad;
+            c.save();
+            c.clipRect(cx - rad, level, cx + rad, cy + rad + 1f);
+            fill.setColor(colour);
+            c.drawCircle(cx, cy, rad - 5f * u, fill);
+            c.restore();
+            // The surface, a brighter line.
+            float half = (float) Math.sqrt(Math.max(0f, (rad - 5f * u) * (rad - 5f * u) - (level - cy) * (level - cy)));
+            line.setColor(0xCCFFFFFF);
+            line.setStrokeWidth(2.5f * u);
+            if (half > 0f) c.drawLine(cx - half, level, cx + half, level, line);
+            // Bubbles rise only while driving.
+            fill.setColor(0x99FFFFFF);
+            for (int i = 0; i < 6; i++) {
+                float span = Math.max(1f, cy + rad - level - 12f * u);
+                float y = cy + rad - 12f * u - ((time * (24f + i * 7f) * u + i * 31f * u) % span);
+                float x = cx + (float) Math.sin(i * 2.1f + time * 1.5f) * rad * 0.5f;
+                c.drawCircle(x, y, (3f + i % 3) * u, fill);
+            }
+        }
+        // The glass, and its cork.
+        line.setColor(GLASS);
+        line.setStrokeWidth(4f * u);
+        c.drawCircle(cx, cy, rad, line);
+        c.drawLine(cx - neckW, neckTop + 12f * u, cx - neckW, cy - rad + 14f * u, line);
+        c.drawLine(cx + neckW, neckTop + 12f * u, cx + neckW, cy - rad + 14f * u, line);
+        r.set(cx - neckW - 4f * u, neckTop - 8f * u, cx + neckW + 4f * u, neckTop + 16f * u);
+        fill.setColor(0xFF9B6B3A);
+        c.drawRoundRect(r, 5f * u, 5f * u, fill);
+        // Dark where the potion is behind the words; outlined where its surface cuts through them.
+        float level = v.socPercent == null ? cy + rad
+                : cy + rad - Math.max(0f, Math.min(1f, v.socPercent / 100f)) * 2f * rad;
+        boolean numberOn = level <= cy - 18f * u, wordOn = level <= cy + 38f * u;
+        String number = fmt(v.socPercent, "%.0f %%", "—");
+        if (!numberOn && level < cy + 30f * u) {
+            text.setStyle(Paint.Style.STROKE);
+            text.setStrokeWidth(7f * u);
+            label(c, number, cx, cy + 22f * u, 62f * u, INK, serif, Paint.Align.CENTER);
+            text.setStyle(Paint.Style.FILL);
+        }
+        label(c, number, cx, cy + 22f * u, 62f * u, numberOn ? INK : low ? RED : BONE, serif, Paint.Align.CENTER);
+        if (low && blinkOn) {
+            label(c, "BATTERY LOW", cx, cy + 56f * u, 21f * u, BONE, face, Paint.Align.CENTER);
+        } else if (!low) {
+            label(c, "BATTERY", cx, cy + 56f * u, 19f * u, wordOn ? INK : POTION, face, Paint.Align.CENTER);
+        }
+    }
+
+    // ---------- The tombstone: the range; small gravestones: the gears ----------
+
+    private void stone(Canvas c, float l, float t, float rr, float b, int colour, int edge, float u) {
+        float mid = (l + rr) / 2f, half = (rr - l) / 2f;
+        path.reset();
+        path.moveTo(l, b);
+        path.lineTo(l, t + half);
+        path.cubicTo(l, t + half * 0.1f, mid - half * 0.5f, t, mid, t);
+        path.cubicTo(mid + half * 0.5f, t, rr, t + half * 0.1f, rr, t + half);
+        path.lineTo(rr, b);
+        path.close();
+        fill.setColor(colour);
+        c.drawPath(path, fill);
+        line.setColor(edge);
+        line.setStrokeWidth(3f * u);
+        c.drawPath(path, line);
+    }
+
+    private void drawTombstone(Canvas c, int w, float u) {
+        float rr = w - 40f * u, l = rr - 250f * u, t = 196f * u, b = 484f * u, mid = (l + rr) / 2f;
+        stone(c, l, t, rr, b, STONE, STONE_DARK, u);
+        label(c, "R.I.P.", mid, t + 70f * u, 36f * u, STONE_DARK, serif, Paint.Align.CENTER);
+        label(c, "HERE LIES", mid, t + 106f * u, 19f * u, 0xFF242230, face, Paint.Align.CENTER);
+        label(c, fmt(v.rangeKm, "%.0f", "—"), mid, t + 186f * u, 86f * u, BONE, serif, Paint.Align.CENTER);
+        label(c, "KM OF RANGE", mid, t + 224f * u, 21f * u, 0xFF242230, face, Paint.Align.CENTER);
+    }
+
+    private void drawGears(Canvas c, int w, float u) {
+        float rr = w - 40f * u, l = rr - 250f * u, t = 496f * u, b = 566f * u;
+        String[] gears = { "P", "R", "N", "D" };
+        String now = Gear.label(v.gear);
+        float step = (rr - l) / 4f, half = 24f * u;
+        for (int i = 0; i < gears.length; i++) {
+            float mid = l + (i + 0.5f) * step;
+            boolean on = gears[i].equals(now);
+            if (on) {
+                fill.setColor(0x55FF8C1A);
+                c.drawCircle(mid, (t + b) / 2f, 42f * u, fill);
+            }
+            stone(c, mid - half, t, mid + half, b, on ? ORANGE : STONE_DARK, on ? CANDLE : 0xFF242230, u);
+            label(c, gears[i], mid, b - 18f * u, 32f * u, on ? INK : 0xB0FFFFFF, serif, Paint.Align.CENTER);
+        }
+    }
+}

app/src/main/java/com/evsuite/abrp/LogOutbox.java

@@ -0,0 +1,162 @@
+package com.evsuite.abrp;
+
+import android.content.Context;
+import android.util.Log;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * Files from the Logs tab (signal recordings) on their way to the car server, so they reach the
+ * owner without a USB stick: kept in {@code files/log-outbox} until the server has them
+ * ({@code PUT /v1/logs/{name}}, gzip, the ingest token in the header), sent at once and, when
+ * that fails, again from the service's tick, at most every {@link #RETRY_MS}. At most
+ * {@link #MAX_FILES} wait; the oldest goes first. Names are the app's own and say nothing about
+ * where the car is.
+ */
+final class LogOutbox {
+
+    static final String DIR = "log-outbox";
+    static final int MAX_FILES = 10;
+    static final long RETRY_MS = 2 * 60_000L;
+    private static final String TAG = "EVABRP.LogOutbox";
+    /** As the server accepts them. */
+    private static final Pattern NAME = Pattern.compile("[a-z0-9][a-z0-9-]{0,79}\\.txt");
+
+    /** What to do with a file after the server's answer. */
+    enum Outcome { SENT, DROP, KEEP }
+
+    private static long lastFailureMs;
+    private static String lastResult;
+
+    private LogOutbox() {}
+
+    /** SENT for a 2xx; KEEP for what may pass later (no answer, 401 before pairing, 408, 429,
+     *  5xx, and a 404 from a server without logs yet); DROP for any other refusal. */
+    static Outcome outcome(int status) {
+        if (status >= 200 && status < 300) return Outcome.SENT;
+        if (status <= 0 || status == 401 || status == 404 || status == 408 || status == 429 || status >= 500) {
+            return Outcome.KEEP;
+        }
+        return Outcome.DROP;
+    }
+
+    static boolean validName(String name) {
+        return name != null && NAME.matcher(name).matches();
+    }
+
+    /** The names to remove so that at most [max] remain: the oldest (by name, which starts
+     *  with what they are and ends in the time) beyond the newest [max]. */
+    static List<String> surplus(List<String> names, int max) {
+        List<String> sorted = new ArrayList<>(names);
+        Collections.sort(sorted);
+        return sorted.size() <= max ? Collections.emptyList() : sorted.subList(0, sorted.size() - max);
+    }
+
+    /** Puts [text] in the outbox as [name]; false when it could not be written. */
+    static synchronized boolean add(Context context, String name, List<String> text) {
+        if (!validName(name)) return false;
+        File dir = new File(context.getFilesDir(), DIR);
+        if (!dir.isDirectory() && !dir.mkdirs()) return false;
+        File tmp = new File(dir, name + ".tmp");
+        try (Writer out = new OutputStreamWriter(new FileOutputStream(tmp), StandardCharsets.UTF_8)) {
+            for (String line : text) out.write(line + "\n");
+        } catch (Exception e) {
+            tmp.delete();
+            return false;
+        }
+        if (!tmp.renameTo(new File(dir, name))) {
+            tmp.delete();
+            return false;
+        }
+        for (String old : surplus(waiting(dir), MAX_FILES)) new File(dir, old).delete();
+        lastFailureMs = 0; // something new: try at once
+        return true;
+    }
+
+    /** Removes what waits under names starting with [prefix]. */
+    static synchronized void dropWaiting(Context context, String prefix) {
+        File dir = new File(context.getFilesDir(), DIR);
+        for (String name : waiting(dir)) if (name.startsWith(prefix)) new File(dir, name).delete();
+    }
+
+    /** Sends what waits, unless the last attempt failed less than {@link #RETRY_MS} ago. Blocking:
+     *  call it off the main thread. */
+    static void sendIfDue(Context context) {
+        synchronized (LogOutbox.class) {
+            if (lastFailureMs != 0 && System.currentTimeMillis() - lastFailureMs < RETRY_MS) return;
+        }
+        send(context);
+    }
+
+    /** Sends every waiting file, oldest first, until one fails. Blocking. */
+    static synchronized void send(Context context) {
+        File dir = new File(context.getFilesDir(), DIR);
+        List<String> names = waiting(dir);
+        if (names.isEmpty()) return;
+        ServerConfig config = ServerConfig.get(context);
+        if (!config.isConfigured()) {
+            lastResult = "no server set up";
+            lastFailureMs = System.currentTimeMillis();
+            return;
+        }
+        Collections.sort(names);
+        for (String name : names) {
+            File file = new File(dir, name);
+            int status;
+            try {
+                byte[] body = gzip(Files.readAllBytes(file.toPath()));
+                status = ServerHttp.send("PUT", config.url + "/v1/logs/" + name, "Bearer " + config.token,
+                        "text/plain; charset=utf-8", "gzip", body).status;
+            } catch (Exception e) {
+                Log.w(TAG, "Log not sent: " + e.getClass().getSimpleName());
+                status = 0;
+            }
+            Outcome outcome = outcome(status);
+            if (outcome == Outcome.KEEP) {
+                lastResult = status == 0 ? "server not reached" : "server answered " + status;
+                lastFailureMs = System.currentTimeMillis();
+                return;
+            }
+            file.delete();
+            lastResult = outcome == Outcome.SENT ? "sent" : "refused by the server (" + status + ")";
+            Log.i(TAG, "Log " + name + ": " + lastResult);
+        }
+        lastFailureMs = 0;
+    }
+
+    /** For the Logs tab: whether the last file reached the server, or why not yet. */
+    static synchronized String status(Context context) {
+        int waiting = waiting(new File(context.getFilesDir(), DIR)).size();
+        if (waiting == 0) return lastResult == null ? null : "sent".equals(lastResult)
+                ? context.getString(R.string.log_outbox_sent) : lastResult;
+        return context.getString(R.string.log_outbox_waiting, waiting, lastResult == null ? "…" : lastResult);
+    }
+
+    private static List<String> waiting(File dir) {
+        String[] names = dir.list();
+        List<String> out = new ArrayList<>();
+        if (names == null) return out;
+        for (String n : Arrays.asList(names)) if (validName(n)) out.add(n);
+        return out;
+    }
+
+    private static byte[] gzip(byte[] data) throws java.io.IOException {
+        ByteArrayOutputStream buf = new ByteArrayOutputStream(data.length / 4 + 64);
+        try (GZIPOutputStream z = new GZIPOutputStream(buf)) {
+            z.write(data);
+        }
+        return buf.toByteArray();
+    }
+}

app/src/main/java/com/evsuite/abrp/MainActivity.java

@@ -77,6 +77,8 @@ public class MainActivity extends AppCompatActivity {
     private boolean inFront;
     /** The pane of each Overview style, by its {@link OverviewStyle} ordinal. */
     private View[] stylePanes;
+    private MusicTap musicTap;
+    private NowPlayingWatcher nowPlaying;
     private View consumptionPane;
     private View chargingPane;
     /** Display, battery, charging price and Wi-Fi. */
@@ -195,6 +197,8 @@ public class MainActivity extends AppCompatActivity {
             @Override public void onPageSelected(int position) {
                 markCurrentPage(position);
                 applyOverviewFullScreen(position);
+                updateMusicTap();
+                updateNowPlaying();
             }
         });
         findViewById(R.id.edge_tab).setOnClickListener(v -> leaveOverviewFullScreen());
@@ -213,6 +217,10 @@ public class MainActivity extends AppCompatActivity {
 
     /** Whether the Overview hides the navigation (the button in the navigation's header). */
     static final String PREF_OVERVIEW_FULLSCREEN = "overview_fullscreen";
+    /** The Overview shows what plays (Tiles, Halloween); on by default. */
+    static final String PREF_NOW_PLAYING = "now_playing";
+    /** The Halloween pumpkin's light follows the music; off by default, so the analyser stays off. */
+    static final String PREF_MUSIC_LIGHT = "music_light";
 
     /** True while the Overview is full screen: the navigation hidden, the edge swipe armed. */
     private boolean overviewFull;
@@ -353,11 +361,17 @@ public class MainActivity extends AppCompatActivity {
         mapRoads = new MapRoads(this);
         gridMapView = new GridView(this, mapRoads);
         visorView = new VisorView(this);
+        HalloweenView halloweenView = new HalloweenView(this);
+        musicTap = new MusicTap(this);
+        nowPlaying = new NowPlayingWatcher(this);
+        halloweenView.setMusic(musicTap);
         java.util.Collections.addAll(canvasStyles, new MinimalView(this), terminalView,
                 new NixieView(this), new ChronographView(this), gridView, gridMapView, new TimeCircuitsView(this),
-                new QuestView(this), visorView, new EmpireView(this));
+                new QuestView(this), visorView, new EmpireView(this), new MuertosView(this), halloweenView);
         View[] canvasPanes = new View[canvasStyles.size()];
         for (int i = 0; i < canvasPanes.length; i++) canvasPanes[i] = drawnPane(canvasStyles.get(i));
+        // Grid with map: its map layer goes under it, in the same pane.
+        ((android.widget.FrameLayout) canvasPanes[canvasStyles.indexOf(gridMapView)]).addView(gridMapView.mapLayer(), 0);
         View[] fixedPanes = { vehiclePane, gaugesPane, cockpitPane, retroPane,
                 futuristicPane, sciFiPane, cartoonPane, mgPane };
         // By OverviewStyle ordinal: the fixed styles, then the canvas styles in their order.
@@ -406,6 +420,14 @@ public class MainActivity extends AppCompatActivity {
             else SignalRecorder.start(this);
             refreshSignalRecorder();
         });
+        logPane.findViewById(R.id.media_probe_button).setOnClickListener(v -> {
+            MediaProbe.start(this);
+            refreshMediaProbe();
+        });
+        logPane.findViewById(R.id.sound_probe_button).setOnClickListener(v -> {
+            SoundProbe.start(this);
+            refreshSoundProbe();
+        });
 
         setUpPager();
         // Back on the page that was open when the activity was recreated (accent colour change).
@@ -496,6 +518,8 @@ public class MainActivity extends AppCompatActivity {
         uiHandler.post(overviewRefresh);
         inFront = true;
         updateMapLocation();
+        updateMusicTap();
+        updateNowPlaying();
     }
 
     @Override
@@ -545,6 +569,8 @@ public class MainActivity extends AppCompatActivity {
         uiHandler.removeCallbacks(overviewRefresh);
         inFront = false;
         updateMapLocation();
+        updateMusicTap();
+        updateNowPlaying();
     }
 
     @Override
@@ -1206,6 +1232,18 @@ public class MainActivity extends AppCompatActivity {
         bindDriveMode();
         bindOverviewStyle();
         bindAccentColor();
+        SwitchMaterial showPlaying = settingsPane.findViewById(R.id.now_playing_switch);
+        showPlaying.setChecked(prefs.getBoolean(PREF_NOW_PLAYING, true));
+        showPlaying.setOnCheckedChangeListener((btn, checked) -> {
+            prefs.edit().putBoolean(PREF_NOW_PLAYING, checked).apply();
+            updateNowPlaying();
+        });
+        SwitchMaterial musicLight = settingsPane.findViewById(R.id.music_light_switch);
+        musicLight.setChecked(prefs.getBoolean(PREF_MUSIC_LIGHT, false));
+        musicLight.setOnCheckedChangeListener((btn, checked) -> {
+            prefs.edit().putBoolean(PREF_MUSIC_LIGHT, checked).apply();
+            updateMusicTap();
+        });
         fullScreenSwitch = settingsPane.findViewById(R.id.full_screen_switch);
         fullScreenSwitch.setChecked(UploadSettings.fullScreen(prefs));
         fullScreenSwitch.setOnCheckedChangeListener((btn, checked) -> {
@@ -1741,6 +1779,69 @@ public class MainActivity extends AppCompatActivity {
         // The accent choices depend on the style ("Original colours" for Retro and Terminal).
         if (settingsPane != null) bindAccentColor();
         updateMapLocation();
+        updateMusicTap();
+        updateNowPlaying();
+    }
+
+    /** The styles that show what plays. */
+    private static boolean showsNowPlaying(OverviewStyle style) {
+        return style == OverviewStyle.TILES || style == OverviewStyle.HALLOWEEN;
+    }
+
+    /** The media sessions are watched only while what plays can be seen, and the switch is on. */
+    private void updateNowPlaying() {
+        ViewPager2 pager = findViewById(R.id.content);
+        nowPlaying.setRunning(inFront && showsNowPlaying(overviewStyle())
+                && prefs.getBoolean(PREF_NOW_PLAYING, true)
+                && pager != null && pager.getCurrentItem() == 0);
+        if (!nowPlaying.isRunning()) showNowPlaying(null);
+    }
+
+    /** The Tiles tile: source, title, artist, a cover when there is one, and how far the song is. */
+    private void showNowPlaying(NowPlaying.Track t) {
+        if (vehiclePane == null) return;
+        View tile = vehiclePane.findViewById(R.id.now_playing_tile);
+        if (tile == null) return; // the narrow layout has no room for it
+        if (t == null) {
+            tile.setVisibility(View.INVISIBLE);
+            return;
+        }
+        tile.setVisibility(View.VISIBLE);
+        String source = getString(t.source == NowPlaying.Source.BLUETOOTH ? R.string.now_playing_bluetooth
+                : t.source == NowPlaying.Source.CARPLAY ? R.string.now_playing_carplay
+                : t.source == NowPlaying.Source.RADIO ? R.string.now_playing_radio : R.string.now_playing_other);
+        setIfChanged(vehiclePane.findViewById(R.id.now_playing_source),
+                t.playing ? source : getString(R.string.now_playing_paused, source));
+        setIfChanged(vehiclePane.findViewById(R.id.now_playing_title), t.title);
+        TextView artist = vehiclePane.findViewById(R.id.now_playing_artist);
+        setIfChanged(artist, t.subtitle == null ? "" : t.subtitle);
+        artist.setVisibility(t.subtitle == null ? View.GONE : View.VISIBLE);
+        android.widget.ImageView cover = vehiclePane.findViewById(R.id.now_playing_cover);
+        android.graphics.Bitmap art = nowPlaying.cover(t);
+        if (cover.getTag() != art) {
+            cover.setTag(art);
+            cover.setImageBitmap(art);
+            cover.setVisibility(art == null ? View.GONE : View.VISIBLE);
+        }
+        android.widget.ProgressBar bar = vehiclePane.findViewById(R.id.now_playing_progress);
+        float progress = t.progressAt(android.os.SystemClock.elapsedRealtime());
+        bar.setVisibility(progress < 0f ? View.INVISIBLE : View.VISIBLE);
+        if (progress >= 0f) bar.setProgress(Math.round(progress * bar.getMax()));
+    }
+
+    private static void setIfChanged(TextView view, CharSequence text) {
+        if (!android.text.TextUtils.equals(view.getText(), text)) view.setText(text);
+    }
+
+    /**
+     * The pumpkin listens only while it can be seen (the app in front, on the Overview, in
+     * Halloween) and only when "Pumpkin light follows the music" is on.
+     */
+    private void updateMusicTap() {
+        ViewPager2 pager = findViewById(R.id.content);
+        musicTap.setRunning(inFront && overviewStyle() == OverviewStyle.HALLOWEEN
+                && prefs.getBoolean(PREF_MUSIC_LIGHT, false)
+                && pager != null && pager.getCurrentItem() == 0);
     }
 
     /**
@@ -1803,6 +1904,12 @@ public class MainActivity extends AppCompatActivity {
         TextView note = settingsPane.findViewById(R.id.accent_note);
         note.setVisibility(style.usesAccent ? View.GONE : View.VISIBLE);
         note.setText(getString(R.string.accent_not_used, styleLabels()[style.ordinal()]));
+        int playing = showsNowPlaying(style) ? View.VISIBLE : View.GONE;
+        settingsPane.findViewById(R.id.now_playing_switch).setVisibility(playing);
+        settingsPane.findViewById(R.id.now_playing_hint).setVisibility(playing);
+        int music = style == OverviewStyle.HALLOWEEN ? View.VISIBLE : View.GONE;
+        settingsPane.findViewById(R.id.music_light_switch).setVisibility(music);
+        settingsPane.findViewById(R.id.music_light_hint).setVisibility(music);
     }
 
     /** The drop-down's labels, by {@link OverviewStyle} ordinal. */
@@ -1817,7 +1924,8 @@ public class MainActivity extends AppCompatActivity {
                 getString(R.string.overview_style_chronograph), getString(R.string.overview_style_grid),
                 getString(R.string.overview_style_grid_map),
                 getString(R.string.overview_style_time_circuits), getString(R.string.overview_style_quest),
-                getString(R.string.overview_style_visor), getString(R.string.overview_style_empire) };
+                getString(R.string.overview_style_visor), getString(R.string.overview_style_empire),
+                getString(R.string.overview_style_muertos), getString(R.string.overview_style_halloween) };
     }
 
     /** The style drop-down; every style is fed on every reading, only the chosen one is shown. */
@@ -1884,6 +1992,10 @@ public class MainActivity extends AppCompatActivity {
         v.tyreRl = unit.format(s.getTirePressures().getRearLeftKpa());
         v.tyreRr = unit.format(s.getTirePressures().getRearRightKpa());
         v.powerTrail = cockpitTrace.snapshot();
+        NowPlaying.Track track = nowPlaying.isRunning() ? nowPlaying.current() : null;
+        v.songTitle = track == null ? null : track.title;
+        v.songArtist = track == null ? null : track.subtitle;
+        showNowPlaying(track);
         retroView.setValues(v);
         flowView.setValues(v);
         sciFiView.setValues(v);
@@ -2323,8 +2435,31 @@ public class MainActivity extends AppCompatActivity {
         if (!status.isEmpty()) text.setText(String.join("\n", status));
     }
 
+    /** The music-sources check: its button and its last report. */
+    private void refreshMediaProbe() {
+        MaterialButton button = logPane.findViewById(R.id.media_probe_button);
+        button.setEnabled(!MediaProbe.running());
+        TextView text = logPane.findViewById(R.id.media_probe_text);
+        java.util.List<String> status = MediaProbe.status(this);
+        text.setVisibility(status.isEmpty() ? View.GONE : View.VISIBLE);
+        if (status.size() > 120) status = status.subList(0, 120);
+        if (!status.isEmpty()) text.setText(String.join("\n", status));
+    }
+
+    /** The sound check: its button and its last report. */
+    private void refreshSoundProbe() {
+        MaterialButton button = logPane.findViewById(R.id.sound_probe_button);
+        button.setEnabled(!SoundProbe.running());
+        TextView text = logPane.findViewById(R.id.sound_probe_text);
+        java.util.List<String> status = SoundProbe.status(this);
+        text.setVisibility(status.isEmpty() ? View.GONE : View.VISIBLE);
+        if (!status.isEmpty()) text.setText(String.join("\n", status));
+    }
+
     private void refreshCallLog() {
         refreshSignalRecorder();
+        refreshMediaProbe();
+        refreshSoundProbe();
         java.util.List<UploadLog.Entry> entries = AbrpUploadService.log().recent();
         // Update steps first: after a failed install, they are what the driver came here for.
         java.util.List<String> updates = UpdateLog.lines(this);

app/src/main/java/com/evsuite/abrp/MapLayerView.java

@@ -0,0 +1,223 @@
+package com.evsuite.abrp;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.os.SystemClock;
+import android.view.View;
+
+/**
+ * The map under "Grid with map": the roads round the car and a ground grid, straight from
+ * above, heading up — drawn once into a hardware layer (a GPU texture) and then only moved and
+ * turned, by the view's own translation and rotation, once per display frame. Nothing is
+ * redrawn while driving until new tiles arrive or the car nears the layer's edge; then it is
+ * drawn again round the car. {@link GridView} draws everything else on top.
+ *
+ * The layer is a square about twice the distance from the car to the farthest screen corner,
+ * plus a margin, so it covers the screen at any angle; the car sits {@link #CAR_FROM_BOTTOM}
+ * layout units above the bottom edge.
+ */
+final class MapLayerView extends View {
+
+    /** Pixels (layout units) per metre, the car's height above the bottom edge, grid spacing. */
+    static final float MAP_SCALE = 1.2f, CAR_FROM_BOTTOM = 150f;
+    private static final float GRID_M = 50f;
+    /** How far the car may move from the layer's centre before it is drawn again, in layout units. */
+    private static final float MARGIN = 280f;
+
+    private final MapRoads map;
+    private final Paint line = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Path[] roads = new Path[RoadTile.CLASSES];
+    private final Path grid = new Path();
+    private int main = 0xFF18E6FF, light = 0xFFC8FCFF;
+
+    /** The layer's centre (world tile units) and what it was drawn from. */
+    private double anchorX = Double.NaN, anchorY;
+    private int drawnVersion = -1;
+    private float drawnScale;
+    /** The car as shown, eased towards where it is (world tile units), and the heading. */
+    private double shownX = Double.NaN, shownY;
+    private float heading = Float.NaN;
+    private boolean showing, ticking;
+    /** The car's speed, from the readings; NaN when unread. */
+    private float speedMps = Float.NaN;
+
+    MapLayerView(Context context, MapRoads map) {
+        super(context);
+        this.map = map;
+        for (int i = 0; i < roads.length; i++) roads[i] = new Path();
+        line.setStyle(Paint.Style.STROKE);
+        line.setStrokeJoin(Paint.Join.ROUND);
+        line.setStrokeCap(Paint.Cap.ROUND);
+        setLayerType(LAYER_TYPE_HARDWARE, null);
+        setVisibility(INVISIBLE);
+        setWillNotDraw(false);
+    }
+
+    void setColours(int main, int light) {
+        this.main = main;
+        this.light = light;
+        invalidate();
+    }
+
+    /** Whether the map is there to be seen (a fix and roads). */
+    boolean isShowing() {
+        return showing;
+    }
+
+    /** Layout units, as GridView uses them, for this size. */
+    private float unit() {
+        View parent = (View) getParent();
+        int w = parent == null ? getWidth() : parent.getWidth() - parent.getPaddingLeft() - parent.getPaddingRight();
+        int h = parent == null ? getHeight() : parent.getHeight() - parent.getPaddingTop() - parent.getPaddingBottom();
+        return Math.min(h / 640f, w / 1100f);
+    }
+
+    @Override
+    protected void onMeasure(int widthSpec, int heightSpec) {
+        int w = MeasureSpec.getSize(widthSpec), h = MeasureSpec.getSize(heightSpec);
+        float u = Math.min(h / 640f, w / 1100f);
+        int side = (int) (2 * (Math.hypot(w / 2f, h - CAR_FROM_BOTTOM * u) + MARGIN * u));
+        setMeasuredDimension(Math.max(side, 1), Math.max(side, 1));
+    }
+
+    /** The car's speed in km/h, or null when unread; GridView passes it with every reading. */
+    void setSpeed(Float kmh) {
+        speedMps = kmh == null ? Float.NaN : kmh / 3.6f;
+    }
+
+    /** Starts the frame loop if it is not running; GridView calls it with every reading. */
+    void kick() {
+        if (!ticking && isAttachedToWindow()) {
+            ticking = true;
+            postOnAnimation(this::tick);
+        }
+    }
+
+    /** One display frame: where the car is, which way, and the layer moved there. */
+    private void tick() {
+        View pane = (View) getParent();
+        if (pane == null || !pane.isShown()) {
+            ticking = false;
+            return;
+        }
+        MapRoads.Fix fix = map.fix();
+        boolean ready = fix != null && !map.tiles().isEmpty() && getWidth() > 0;
+        if (ready != showing) {
+            showing = ready;
+            setVisibility(ready ? VISIBLE : INVISIBLE);
+        }
+        if (!ready) {
+            ticking = false;
+            return;
+        }
+        float target = Float.isNaN(fix.bearing) ? (Float.isNaN(heading) ? 0f : heading) : fix.bearing;
+        if (Float.isNaN(heading)) heading = target;
+        else heading = (heading + (((target - heading) % 360f + 540f) % 360f - 180f) * 0.12f + 360f) % 360f;
+
+        // Between fixes the car runs on with the speed (at most 2.5 s), and what is shown glides
+        // there rather than jumping with each fix.
+        double mpu = MapGeometry.metresPerUnit(fix.lat);
+        float ran = Float.isNaN(fix.bearing) || Float.isNaN(speedMps) ? 0f
+                : speedMps * Math.min(2.5f, (SystemClock.elapsedRealtime() - fix.elapsedMs) / 1000f);
+        double run = Math.toRadians(Float.isNaN(fix.bearing) ? 0f : fix.bearing);
+        double carX = MapGeometry.worldX(fix.lon) + ran * Math.sin(run) / mpu;
+        double carY = MapGeometry.worldY(fix.lat) - ran * Math.cos(run) / mpu;
+        if (Double.isNaN(shownX) || Math.hypot(carX - shownX, carY - shownY) * mpu > 200) {
+            shownX = carX;
+            shownY = carY;
+        } else {
+            shownX += (carX - shownX) * 0.15;
+            shownY += (carY - shownY) * 0.15;
+        }
+
+        float u = unit(), px = MAP_SCALE * u;
+        if (drawnVersion != map.version() || Double.isNaN(anchorX) || drawnScale != px
+                || Math.hypot(shownX - anchorX, shownY - anchorY) * mpu * px > MARGIN * u) {
+            build(shownX, shownY, mpu);
+            drawnScale = px;
+            invalidate(); // the only redraw of the layer
+        }
+
+        // The car's spot in the layer goes to its spot on screen, turned round it.
+        float half = getWidth() / 2f;
+        float inX = half + (float) ((shownX - anchorX) * mpu) * px;
+        float inY = half + (float) ((shownY - anchorY) * mpu) * px;
+        float carSx = pane.getPaddingLeft() + (pane.getWidth() - pane.getPaddingLeft() - pane.getPaddingRight()) / 2f;
+        float carSy = pane.getHeight() - pane.getPaddingBottom() - CAR_FROM_BOTTOM * u;
+        setPivotX(inX);
+        setPivotY(inY);
+        setRotation(-heading);
+        setTranslationX(carSx - getLeft() - inX);
+        setTranslationY(carSy - getTop() - inY);
+        postOnAnimation(this::tick);
+    }
+
+    /** The roads and the grid in metres east and south of an anchor at the car. */
+    private void build(double atX, double atY, double mpu) {
+        anchorX = atX;
+        anchorY = atY;
+        drawnVersion = map.version();
+        float m = (float) mpu;
+        for (Path p : roads) p.reset();
+        float u = unit();
+        double reach = getWidth() / 2f / (MAP_SCALE * u);
+        double range = reach / mpu;
+        for (RoadTile tile : map.tiles()) {
+            double ox = (double) tile.x * MapGeometry.EXTENT - atX, oy = (double) tile.y * MapGeometry.EXTENT - atY;
+            if (ox > range || oy > range || ox + MapGeometry.EXTENT < -range || oy + MapGeometry.EXTENT < -range) {
+                continue;
+            }
+            float fx = (float) ox, fy = (float) oy;
+            for (int i = 0; i < tile.points.length; i++) {
+                int[] b = tile.bounds[i];
+                if (fx + b[2] < -range || fx + b[0] > range || fy + b[3] < -range || fy + b[1] > range) continue;
+                Path p = roads[tile.classes[i]];
+                int[] pts = tile.points[i];
+                p.moveTo((fx + pts[0]) * m, (fy + pts[1]) * m);
+                for (int k = 2; k < pts.length; k += 2) p.lineTo((fx + pts[k]) * m, (fy + pts[k + 1]) * m);
+            }
+        }
+        // Grid lines on whole multiples of GRID_M east and north, so they stay put on the ground.
+        grid.reset();
+        float r = (float) reach;
+        float offE = (float) ((atX * mpu) % GRID_M), offS = (float) ((atY * mpu) % GRID_M);
+        int lines = (int) (r / GRID_M) + 1;
+        for (int k = -lines; k <= lines; k++) {
+            float x = k * GRID_M - offE, y = k * GRID_M - offS;
+            grid.moveTo(x, -r);
+            grid.lineTo(x, r);
+            grid.moveTo(-r, y);
+            grid.lineTo(r, y);
+        }
+    }
+
+    @Override
+    protected void onDraw(Canvas c) {
+        if (Double.isNaN(anchorX) || drawnScale <= 0f) return;
+        float u = unit(), px = drawnScale;
+        c.save();
+        c.translate(getWidth() / 2f, getHeight() / 2f);
+        c.scale(px, px);
+        stroke(c, grid, AccentColor.withAlpha(main, 0x26), 1f * u / px);
+        stroke(c, roads[3], AccentColor.withAlpha(main, 0xA0), 1.6f * u / px);
+        stroke(c, roads[2], AccentColor.withAlpha(main, 0xD8), 2.2f * u / px);
+        glow(c, roads[1], main, 2.6f * u / px);
+        glow(c, roads[0], light, 3.4f * u / px);
+        c.restore();
+    }
+
+    private void stroke(Canvas c, Path p, int colour, float width) {
+        line.setColor(colour);
+        line.setStrokeWidth(width);
+        c.drawPath(p, line);
+    }
+
+    /** As GridView's glow: two wide faint strokes under a sharp one. */
+    private void glow(Canvas c, Path p, int colour, float width) {
+        stroke(c, p, AccentColor.withAlpha(colour, 0x18), width * 6f);
+        stroke(c, p, AccentColor.withAlpha(colour, 0x40), width * 3f);
+        stroke(c, p, colour, width);
+    }
+}

app/src/main/java/com/evsuite/abrp/MapRoads.java

@@ -49,7 +49,8 @@ final class MapRoads {
     private static final String TAG = "MapRoads";
     private static final int DISK_TILES = 400;
     private static final long DISK_AGE_MS = 30L * 24 * 60 * 60 * 1000;
-    private static final long RETRY_MS = 60_000L;
+    /** A tile the server did not have yet (it goes on fetching) is asked for again after this. */
+    private static final long RETRY_MS = 15_000L;
     /** A fix older than this is not drawn from. */
     static final long FIX_FRESH_MS = 15_000L;
 
@@ -64,6 +65,8 @@ final class MapRoads {
         return t;
     });
     private volatile Fix fix;
+    /** Goes up whenever a tile arrives or is dropped, so a view knows to rebuild its shapes. */
+    private volatile int version;
     /** The last bearing while moving; GPS has none at a standstill. */
     private volatile float bearing = Float.NaN;
     private volatile boolean serverMissing;
@@ -99,6 +102,10 @@ final class MapRoads {
         return f == null || SystemClock.elapsedRealtime() - f.elapsedMs > FIX_FRESH_MS ? null : f;
     }
 
+    int version() {
+        return version;
+    }
+
     Collection<RoadTile> tiles() {
         return tiles.values();
     }
@@ -115,7 +122,10 @@ final class MapRoads {
     /** Queues the 3×3 tiles round (cx, cy), the car's own first, and forgets far ones. */
     private void want(int cx, int cy) {
         for (Long key : tiles.keySet()) {
-            if (Math.abs(MapGeometry.keyX(key) - cx) > 2 || Math.abs(MapGeometry.keyY(key) - cy) > 2) tiles.remove(key);
+            if (Math.abs(MapGeometry.keyX(key) - cx) > 2 || Math.abs(MapGeometry.keyY(key) - cy) > 2) {
+                tiles.remove(key);
+                version++;
+            }
         }
         int[][] order = { {0, 0}, {0, -1}, {1, 0}, {0, 1}, {-1, 0}, {1, -1}, {1, 1}, {-1, 1}, {-1, -1} };
         long now = SystemClock.elapsedRealtime();
@@ -151,6 +161,7 @@ final class MapRoads {
         }
         if (cached != null) {
             tiles.put(key, cached);
+            version++;
             if (System.currentTimeMillis() - file.lastModified() < DISK_AGE_MS) return;
         }
         ServerConfig config = ServerConfig.get(context);
@@ -171,6 +182,7 @@ final class MapRoads {
             }
             failedAt.remove(key);
             tiles.put(key, tile);
+            version++;
             save(file, r.body);
         } catch (Exception e) {
             Log.w(TAG, "Map tile not loaded: " + e.getClass().getSimpleName());

app/src/main/java/com/evsuite/abrp/MediaProbe.java

@@ -0,0 +1,283 @@
+package com.evsuite.abrp;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.content.pm.ResolveInfo;
+import android.graphics.Bitmap;
+import android.media.AudioManager;
+import android.media.AudioPlaybackConfiguration;
+import android.media.MediaMetadata;
+import android.media.session.MediaController;
+import android.media.session.MediaSessionManager;
+import android.media.session.PlaybackState;
+import android.service.media.MediaBrowserService;
+
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+import java.util.TreeSet;
+
+/**
+ * The music-sources check on the Logs tab: where the head unit tells what is playing, before
+ * the Overview shows it. Three places, all read only:
+ * <ol>
+ *   <li>the playback Android's audio service reports (which app plays, for what use);</li>
+ *   <li>the active media sessions ({@code MediaSessionManager.getActiveSessions}, which needs
+ *       MEDIA_CONTENT_CONTROL: the car build has it as the system user), with their song and
+ *       state;</li>
+ *   <li>every media browser service on the head unit, listed but not connected to (2.42.1:
+ *       a connection is not harmless, see {@link #browsers}).</li>
+ * </ol>
+ * No other app's service is bound; nothing is played, paused or skipped. The report goes where
+ * a signal recording goes ({@link SignalRecorder#saveCopies}): the app, a USB stick, the server.
+ */
+final class MediaProbe {
+
+    static final String FILE = "media_probe.txt";
+
+    private static volatile boolean running;
+    private static long startedMs;
+    private static List<String> report = new ArrayList<>();
+    private static String result;
+
+    private MediaProbe() {}
+
+    static synchronized boolean running() {
+        return running;
+    }
+
+    static synchronized void start(Context context) {
+        if (running) return;
+        Context app = context.getApplicationContext();
+        running = true;
+        startedMs = System.currentTimeMillis();
+        result = null;
+        report = new ArrayList<>();
+        new Thread(() -> probe(app), "media-probe").start();
+    }
+
+    private static void probe(Context app) {
+        List<String> out = new ArrayList<>();
+        out.add("Media probe, " + SignalRecording.time(startedMs) + ", app " + BuildConfig.VERSION_NAME);
+        String saved;
+        try {
+            out.add("");
+            audio(app, out);
+            out.add("");
+            sessions(app, out);
+            out.add("");
+            browsers(app, out);
+        } catch (Throwable t) {
+            out.add("probe stopped: " + t.getClass().getSimpleName());
+        } finally {
+            String name = "media-probe-" + new SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+                    .format(new Date(startedMs)) + ".txt";
+            saved = SignalRecorder.saveCopies(app, FILE, name, out);
+            synchronized (MediaProbe.class) {
+                report = out;
+                result = saved;
+                running = false;
+            }
+        }
+    }
+
+    /** Who plays audio, as Android's audio service sees it. */
+    private static void audio(Context app, List<String> out) {
+        out.add("Audio playing (AudioManager):");
+        AudioManager am = (AudioManager) app.getSystemService(Context.AUDIO_SERVICE);
+        if (am == null) {
+            out.add("  no audio service");
+            return;
+        }
+        try {
+            out.add("  music active: " + am.isMusicActive() + ", mode " + am.getMode());
+        } catch (RuntimeException e) {
+            out.add("  music active: unreadable (" + e.getClass().getSimpleName() + ")");
+        }
+        List<AudioPlaybackConfiguration> players;
+        try {
+            players = am.getActivePlaybackConfigurations();
+        } catch (RuntimeException e) {
+            out.add("  players: unreadable (" + e.getClass().getSimpleName() + ")");
+            return;
+        }
+        if (players == null || players.isEmpty()) {
+            out.add("  players: none");
+            return;
+        }
+        PackageManager pm = app.getPackageManager();
+        for (AudioPlaybackConfiguration p : players) {
+            StringBuilder line = new StringBuilder("  player: ");
+            try {
+                line.append(MediaProbeText.usage(p.getAudioAttributes().getUsage()));
+            } catch (RuntimeException e) {
+                line.append("usage ?");
+            }
+            // The app and state are system APIs: read when the platform lets the system user.
+            Integer uid = hiddenInt(p, "getClientUid");
+            if (uid != null) line.append(", uid ").append(uid).append(' ').append(packages(pm, uid));
+            Integer state = hiddenInt(p, "getPlayerState");
+            if (state != null) line.append(", ").append(MediaProbeText.playerState(state));
+            if (uid == null && state == null) line.append(" — ").append(MediaProbeText.clean(p.toString()));
+            out.add(line.toString());
+        }
+    }
+
+    private static Integer hiddenInt(Object target, String method) {
+        try {
+            Object v = target.getClass().getMethod(method).invoke(target);
+            return v instanceof Integer ? (Integer) v : null;
+        } catch (Throwable t) {
+            return null;
+        }
+    }
+
+    private static String packages(PackageManager pm, int uid) {
+        try {
+            String[] names = pm.getPackagesForUid(uid);
+            return names == null ? "(no package)" : String.join(", ", names);
+        } catch (RuntimeException e) {
+            return "(package unreadable)";
+        }
+    }
+
+    /** The media sessions apps publish, newest first, with their song. */
+    private static void sessions(Context app, List<String> out) {
+        out.add("Active media sessions (MediaSessionManager):");
+        List<MediaController> controllers;
+        try {
+            MediaSessionManager msm = (MediaSessionManager) app.getSystemService(Context.MEDIA_SESSION_SERVICE);
+            controllers = msm == null ? null : msm.getActiveSessions(null);
+        } catch (Throwable t) {
+            out.add("  not readable: " + t.getClass().getSimpleName() + " " + MediaProbeText.clean(t.getMessage()));
+            return;
+        }
+        if (controllers == null || controllers.isEmpty()) {
+            out.add("  none");
+            return;
+        }
+        for (MediaController c : controllers) {
+            out.add("  session of " + safe(c::getPackageName));
+            describe(c, out, "    ");
+        }
+    }
+
+    /**
+     * Every media browser service, listed only. 2.42.0 connected to each, as the car's media
+     * library does; on the car that was not harmless: the Bluetooth music stopped (the AOSP car
+     * radio's service, `com.android.car.radio/.RadioService`, answered "connecting", most likely
+     * taking the audio) and the Local Media Player asked for access to media. The active sessions
+     * above already carry the song of whatever plays, CarPlay's and Bluetooth's included, so no
+     * service is bound any more.
+     */
+    private static void browsers(Context app, List<String> out) {
+        out.add("Media browser services (" + MediaBrowserService.SERVICE_INTERFACE + "), listed, not connected to:");
+        try {
+            List<ResolveInfo> found = app.getPackageManager()
+                    .queryIntentServices(new Intent(MediaBrowserService.SERVICE_INTERFACE), 0);
+            if (found == null || found.isEmpty()) {
+                out.add("  none");
+                return;
+            }
+            for (ResolveInfo ri : found) {
+                if (ri.serviceInfo == null) continue;
+                out.add("  " + new ComponentName(ri.serviceInfo.packageName, ri.serviceInfo.name)
+                        .flattenToShortString());
+            }
+        } catch (RuntimeException e) {
+            out.add("  list not readable: " + e.getClass().getSimpleName());
+        }
+    }
+
+    /** A session's state and everything its song's metadata holds. */
+    private static void describe(MediaController c, List<String> out, String indent) {
+        try {
+            PlaybackState s = c.getPlaybackState();
+            out.add(indent + "state: " + (s == null ? "(none)"
+                    : MediaProbeText.playbackState(s.getState()) + ", at "
+                            + MediaProbeText.duration(s.getPosition()) + ", actions 0x"
+                            + Long.toHexString(s.getActions())));
+        } catch (Throwable t) {
+            out.add(indent + "state: unreadable (" + t.getClass().getSimpleName() + ")");
+        }
+        try {
+            MediaController.PlaybackInfo info = c.getPlaybackInfo();
+            if (info != null) {
+                out.add(indent + "plays " + (info.getPlaybackType() == MediaController.PlaybackInfo.PLAYBACK_TYPE_REMOTE
+                        ? "remotely" : "locally") + ", for "
+                        + MediaProbeText.usage(info.getAudioAttributes().getUsage()));
+            }
+        } catch (Throwable ignored) {
+            // Not every session says.
+        }
+        MediaMetadata m;
+        try {
+            m = c.getMetadata();
+        } catch (Throwable t) {
+            out.add(indent + "song: unreadable (" + t.getClass().getSimpleName() + ")");
+            return;
+        }
+        if (m == null) {
+            out.add(indent + "song: (no metadata)");
+            return;
+        }
+        for (String key : new TreeSet<>(m.keySet())) {
+            String shortKey = key.startsWith("android.media.metadata.")
+                    ? key.substring("android.media.metadata.".length()) : key;
+            out.add(indent + shortKey + ": " + value(m, key));
+        }
+    }
+
+    /** One metadata value: a picture by its size, text cleaned, anything else as a number. */
+    private static String value(MediaMetadata m, String key) {
+        try {
+            Bitmap bitmap = m.getBitmap(key);
+            if (bitmap != null) return "picture " + bitmap.getWidth() + "×" + bitmap.getHeight();
+        } catch (Throwable ignored) {
+            // not a picture
+        }
+        try {
+            CharSequence text = m.getText(key);
+            if (text != null) return MediaProbeText.clean(text);
+        } catch (Throwable ignored) {
+            // not text
+        }
+        try {
+            if (key.equals(MediaMetadata.METADATA_KEY_DURATION)) {
+                return MediaProbeText.duration(m.getLong(key));
+            }
+            if (m.getRating(key) != null) return "rating";
+            return Long.toString(m.getLong(key));
+        } catch (Throwable t) {
+            return "?";
+        }
+    }
+
+    private static String safe(java.util.concurrent.Callable<String> read) {
+        try {
+            return MediaProbeText.clean(read.call());
+        } catch (Throwable t) {
+            return "?";
+        }
+    }
+
+    /** What the Logs tab shows: the state, then the report. */
+    static synchronized List<String> status(Context context) {
+        List<String> lines = new ArrayList<>();
+        if (startedMs == 0) return lines;
+        if (running) {
+            lines.add(context.getString(R.string.media_probe_running));
+            return lines;
+        }
+        lines.add(context.getString(R.string.media_probe_done, SignalRecording.time(startedMs),
+                result == null ? "…" : result));
+        String sent = LogOutbox.status(context);
+        if (sent != null) lines.add(sent);
+        lines.addAll(report.subList(Math.min(1, report.size()), report.size()));
+        return lines;
+    }
+}

app/src/main/java/com/evsuite/abrp/MediaProbeText.java

@@ -0,0 +1,88 @@
+package com.evsuite.abrp;
+
+import java.util.Locale;
+
+/**
+ * The words of {@link MediaProbe}'s report: Android's numbers for playback and audio states as
+ * names, and text from other apps made safe for one line. Android-free and unit-tested.
+ */
+final class MediaProbeText {
+
+    /** Longest text kept from another app (a title, an artist). */
+    static final int MAX_TEXT = 120;
+
+    private MediaProbeText() {}
+
+    /** Another app's text on one line: control characters out, at most {@link #MAX_TEXT}. */
+    static String clean(CharSequence text) {
+        if (text == null) return "(none)";
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < text.length() && sb.length() < MAX_TEXT; i++) {
+            char c = text.charAt(i);
+            sb.append(Character.isISOControl(c) ? ' ' : c);
+        }
+        String s = sb.toString().trim();
+        if (text.length() > MAX_TEXT) s += "…";
+        return s.isEmpty() ? "(empty)" : s;
+    }
+
+    /** {@code android.media.session.PlaybackState} STATE_*. */
+    static String playbackState(int state) {
+        switch (state) {
+            case 0: return "none";
+            case 1: return "stopped";
+            case 2: return "paused";
+            case 3: return "playing";
+            case 4: return "fast forwarding";
+            case 5: return "rewinding";
+            case 6: return "buffering";
+            case 7: return "error";
+            case 8: return "connecting";
+            case 9: return "skipping to previous";
+            case 10: return "skipping to next";
+            case 11: return "skipping to queue item";
+            default: return "state " + state;
+        }
+    }
+
+    /** {@code android.media.AudioAttributes} USAGE_*. */
+    static String usage(int usage) {
+        switch (usage) {
+            case 0: return "unknown";
+            case 1: return "media";
+            case 2: return "voice call";
+            case 3: return "call signalling";
+            case 4: return "alarm";
+            case 5: return "notification";
+            case 6: return "ringtone";
+            case 7: case 8: case 9: case 10: return "notification (" + usage + ")";
+            case 11: return "accessibility";
+            case 12: return "navigation guidance";
+            case 13: return "sonification";
+            case 14: return "game";
+            case 15: return "virtual source";
+            case 16: return "assistant";
+            default: return "usage " + usage;
+        }
+    }
+
+    /** {@code android.media.AudioPlaybackConfiguration} PLAYER_STATE_*. */
+    static String playerState(int state) {
+        switch (state) {
+            case -1: return "unknown";
+            case 0: return "released";
+            case 1: return "idle";
+            case 2: return "started";
+            case 3: return "paused";
+            case 4: return "stopped";
+            default: return "state " + state;
+        }
+    }
+
+    /** A position or duration in milliseconds as m:ss; negative (unknown) as "?". */
+    static String duration(long ms) {
+        if (ms < 0) return "?";
+        long s = ms / 1000;
+        return String.format(Locale.US, "%d:%02d", s / 60, s % 60);
+    }
+}

app/src/main/java/com/evsuite/abrp/MuertosView.java

@@ -0,0 +1,501 @@
+package com.evsuite.abrp;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.graphics.RadialGradient;
+import android.graphics.RectF;
+import android.graphics.Shader;
+import android.graphics.Typeface;
+import android.os.SystemClock;
+
+import java.util.Locale;
+
+/**
+ * The Día de Muertos Overview style: an ofrenda at night, the altar families build to welcome
+ * their dead back for a visit. A celebration, so bright and warm, not frightening.
+ *
+ * Across the top the papel picado, cut-paper flags on a string: the battery, one flag per 10 %,
+ * those not lit hanging dark. In the middle a calavera, a decorated sugar skull, with the speed
+ * on its forehead and marigolds (cempasúchil) for eyes; round it a ring of marigolds is the power,
+ * clockwise while drawing, turquoise and anticlockwise while regenerating. On the left the candles
+ * of the altar: the range, one candle per 50 km. Along the bottom the path of marigold petals that
+ * leads the visitors home: the last two minutes of power, higher the more power. On the right the
+ * clock in a tin frame, P R N D as four small marigolds, and trip, usage, climate and odometer on
+ * the altar cloth. Below 20 % the battery turns red and says so. Unread values show "—" and light
+ * nothing.
+ *
+ * The altar is drawn once into a bitmap per size; only the readings go over it. The flags sway and
+ * the flames flicker (about 30 frames a second) only while the car moves and the view is on screen.
+ */
+final class MuertosView extends ClusterCanvasView {
+
+    private static final int FLAGS = 10, PETALS = 24, CANDLES = 8;
+    private static final int NIGHT = 0xFF160A26, PLUM = 0xFF2C1242, CLOTH = 0xFF3A0F3E, BONE = 0xFFF8EEDC;
+    private static final int INK = 0xFF2A0E36, MARIGOLD = 0xFFFF9A1F, GOLD = 0xFFFFC94A, TURQUOISE = 0xFF2EE6D0;
+    private static final int PINK = 0xFFFF2E93, RED = 0xFFFF3B47, FLAME = 0xFFFFD36B, WAX = 0xFFF4E6C8;
+    private static final int[] PAPER = { 0xFFFF2E93, 0xFFFF9A1F, 0xFF2EE6D0, 0xFFFFD23F, 0xFF9B5CFF };
+
+    private final Paint fill = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint line = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint text = new Paint(Paint.ANTI_ALIAS_FLAG);
+    private final Paint image = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
+    private final Path path = new Path();
+    private final Path flag = new Path();
+    private final RectF r = new RectF();
+    private final Typeface serif = Typeface.create("serif", Typeface.BOLD);
+    private final Typeface face = Typeface.create("sans-serif-condensed", Typeface.BOLD);
+    private final Typeface thin = Typeface.create("sans-serif-condensed", Typeface.NORMAL);
+
+    private Bitmap scene, marigold, turquoise;
+    private int sceneW, sceneH;
+    private float time;
+    private long lastFrame;
+
+    MuertosView(Context context) {
+        super(context);
+        line.setStyle(Paint.Style.STROKE);
+        line.setStrokeCap(Paint.Cap.ROUND);
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+        scene = null;
+        marigold = null;
+        turquoise = null;
+        sceneW = 0;
+    }
+
+    @Override
+    protected void onDraw(Canvas c) {
+        super.onDraw(c);
+        int w = getWidth(), h = getHeight();
+        if (w <= 0 || h <= 0) return;
+        float u = Math.min(h / 640f, w / 1100f);
+        boolean moving = v.speedKmh != null && v.speedKmh > 0.5f;
+        if (moving) {
+            long now = SystemClock.uptimeMillis();
+            time += lastFrame == 0 ? 0f : Math.min(0.2f, (now - lastFrame) / 1000f);
+            lastFrame = now;
+        } else {
+            lastFrame = 0;
+        }
+        if (scene == null || sceneW != w || sceneH != h) buildScene(w, h, u);
+        c.drawBitmap(scene, 0, 0, image);
+        float cx = w / 2f, cy = 345f * u;
+        drawFlags(c, w, u);
+        drawRing(c, cx, cy, u);
+        drawSpeed(c, cx, cy, u);
+        drawBattery(c, u);
+        drawCandles(c, u, moving);
+        drawPetals(c, w, h, u);
+        drawClock(c, w, u);
+        drawGears(c, w, u);
+        drawRows(c, w, h, u);
+        keepAnimating(moving, 33);
+    }
+
+    private void label(Canvas c, String s, float x, float y, float size, int colour, Typeface tf, Paint.Align a) {
+        text.setTypeface(tf);
+        text.setTextSize(size);
+        text.setTextAlign(a);
+        text.setColor(colour);
+        c.drawText(s, x, y, text);
+    }
+
+    // ---------- The altar, once per size ----------
+
+    private void buildScene(int w, int h, float u) {
+        scene = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
+        sceneW = w;
+        sceneH = h;
+        marigold = flower(44f * u, MARIGOLD, GOLD, 0xFFE06A00);
+        turquoise = flower(44f * u, TURQUOISE, 0xFFA8FFF4, 0xFF0E9C90);
+        buildFlag(u);
+        Canvas c = new Canvas(scene);
+        c.drawColor(NIGHT);
+        Paint glow = new Paint();
+        glow.setShader(new RadialGradient(w / 2f, 345f * u, Math.max(w, h) * 0.6f,
+                new int[] { 0xFF4A1C5E, PLUM, NIGHT }, new float[] { 0f, 0.45f, 1f }, Shader.TileMode.CLAMP));
+        c.drawRect(0, 0, w, h, glow);
+        // A scatter of stars, always the same.
+        fill.setColor(0x66FFFFFF);
+        for (int i = 0; i < 70; i++) {
+            float x = ((i * 137 + 31) % 997) / 997f * w, y = (110f + (i * 71 % 113) * 3f) * u;
+            c.drawCircle(x, y, (i % 3 == 0 ? 1.8f : 1f) * u, fill);
+        }
+        // The string the flags hang on.
+        line.setColor(0x99FFFFFF);
+        line.setStrokeWidth(1.5f * u);
+        c.drawLine(0, 12f * u, w, 12f * u, line);
+        drawSkull(c, w / 2f, 345f * u, u);
+        drawAltarCloth(c, w, u);
+        drawCandleStands(c, u);
+    }
+
+    /** One flower on a small bitmap: outer petals, inner petals, heart. */
+    private Bitmap flower(float size, int outer, int inner, int shade) {
+        int s = (int) Math.ceil(size);
+        Bitmap b = Bitmap.createBitmap(s, s, Bitmap.Config.ARGB_8888);
+        Canvas c = new Canvas(b);
+        drawFlower(c, s / 2f, s / 2f, s / 2f, outer, inner, shade);
+        return b;
+    }
+
+    private void drawFlower(Canvas c, float x, float y, float rad, int outer, int inner, int shade) {
+        Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
+        for (int ring = 0; ring < 3; ring++) {
+            int n = 12 - ring * 3;
+            float d = rad * (0.68f - ring * 0.24f), pr = rad * (0.32f - ring * 0.05f);
+            for (int i = 0; i < n; i++) {
+                double a = Math.PI * 2 * i / n + ring * 0.3;
+                p.setColor(ring == 0 ? (i % 2 == 0 ? outer : shade) : ring == 1 ? (i % 2 == 0 ? inner : outer) : inner);
+                c.drawCircle(x + (float) Math.cos(a) * d, y + (float) Math.sin(a) * d, pr, p);
+            }
+        }
+        p.setColor(shade);
+        c.drawCircle(x, y, rad * 0.14f, p);
+    }
+
+    /** A paper flag with its holes cut out: scalloped below, a flower and diamonds in it. */
+    private void buildFlag(float u) {
+        float w = 100f * u, h = 84f * u;
+        flag.reset();
+        flag.setFillType(Path.FillType.EVEN_ODD);
+        flag.moveTo(0, 0);
+        flag.lineTo(w, 0);
+        flag.lineTo(w, h - 8f * u);
+        int scallops = 6;
+        float sw = w / scallops;
+        for (int i = scallops; i > 0; i--) {
+            float x = i * sw;
+            flag.quadTo(x - sw / 2f, h + 8f * u, x - sw, h - 8f * u);
+        }
+        flag.close();
+        // The middle: a flower of eight petals round a round hole.
+        float cx = w / 2f, cy = h * 0.46f;
+        flag.addCircle(cx, cy, 6f * u, Path.Direction.CW);
+        for (int i = 0; i < 8; i++) {
+            double a = Math.PI / 4 * i;
+            float px = cx + (float) Math.cos(a) * 17f * u, py = cy + (float) Math.sin(a) * 17f * u;
+            diamond(flag, px, py, 7f * u, 5f * u, a);
+        }
+        // Corners and borders.
+        for (int i = 0; i < 6; i++) {
+            float x = (i + 0.5f) * w / 6f;
+            diamond(flag, x, 8f * u, 5f * u, 3f * u, 0);
+            if (i == 0 || i == 5) {
+                diamond(flag, x, h * 0.3f, 4f * u, 6f * u, 0);
+                diamond(flag, x, h * 0.62f, 4f * u, 6f * u, 0);
+            }
+        }
+    }
+
+    private static void diamond(Path p, float x, float y, float a, float b, double turn) {
+        float ca = (float) Math.cos(turn), sa = (float) Math.sin(turn);
+        p.moveTo(x + a * ca, y + a * sa);
+        p.lineTo(x - b * sa, y + b * ca);
+        p.lineTo(x - a * ca, y - a * sa);
+        p.lineTo(x + b * sa, y - b * ca);
+        p.close();
+    }
+
+    /** The calavera: the bone, the decoration, the teeth. Its speed and ring go over it. */
+    private void drawSkull(Canvas c, float cx, float cy, float u) {
+        float top = cy - 150f * u, jaw = cy + 150f * u;
+        // Bone.
+        path.reset();
+        path.moveTo(cx, top);
+        path.cubicTo(cx + 110f * u, top, cx + 148f * u, cy - 70f * u, cx + 142f * u, cy + 8f * u);
+        path.cubicTo(cx + 140f * u, cy + 48f * u, cx + 112f * u, cy + 62f * u, cx + 84f * u, cy + 74f * u);
+        path.lineTo(cx + 78f * u, jaw - 8f * u);
+        path.quadTo(cx, jaw + 6f * u, cx - 78f * u, jaw - 8f * u);
+        path.lineTo(cx - 84f * u, cy + 74f * u);
+        path.cubicTo(cx - 112f * u, cy + 62f * u, cx - 140f * u, cy + 48f * u, cx - 142f * u, cy + 8f * u);
+        path.cubicTo(cx - 148f * u, cy - 70f * u, cx - 110f * u, top, cx, top);
+        path.close();
+        fill.setColor(BONE);
+        c.drawPath(path, fill);
+        line.setColor(PINK);
+        line.setStrokeWidth(3f * u);
+        c.drawPath(path, line);
+        // A band of scallops under the forehead, where the speed stands above.
+        line.setColor(PINK);
+        line.setStrokeWidth(2.5f * u);
+        for (int i = -4; i < 4; i++) {
+            float x = cx + i * 26f * u;
+            r.set(x, cy - 54f * u, x + 26f * u, cy - 28f * u);
+            c.drawArc(r, 0, 180, false, line);
+        }
+        fill.setColor(TURQUOISE);
+        for (int i = -4; i <= 4; i++) c.drawCircle(cx + i * 26f * u, cy - 41f * u, 3f * u, fill);
+        // Eyes: dark sockets with a marigold each, a ring of dots round them.
+        for (int side = -1; side <= 1; side += 2) {
+            float ex = cx + side * 62f * u, ey = cy + 4f * u;
+            fill.setColor(INK);
+            c.drawCircle(ex, ey, 36f * u, fill);
+            drawFlower(c, ex, ey, 31f * u, MARIGOLD, GOLD, 0xFFE06A00);
+            fill.setColor(PINK);
+            for (int i = 0; i < 14; i++) {
+                double a = Math.PI * 2 * i / 14;
+                c.drawCircle(ex + (float) Math.cos(a) * 43f * u, ey + (float) Math.sin(a) * 43f * u, 2.5f * u, fill);
+            }
+            // A small flower on each cheek.
+            drawFlower(c, cx + side * 92f * u, cy + 56f * u, 10f * u, 0xFF9B5CFF, 0xFFD2B8FF, 0xFF6A32C8);
+        }
+        // Nose: an upside-down heart.
+        path.reset();
+        path.moveTo(cx, cy + 30f * u);
+        path.cubicTo(cx + 18f * u, cy + 46f * u, cx + 20f * u, cy + 66f * u, cx + 8f * u, cy + 66f * u);
+        path.quadTo(cx + 2f * u, cy + 66f * u, cx, cy + 58f * u);
+        path.quadTo(cx - 2f * u, cy + 66f * u, cx - 8f * u, cy + 66f * u);
+        path.cubicTo(cx - 20f * u, cy + 66f * u, cx - 18f * u, cy + 46f * u, cx, cy + 30f * u);
+        path.close();
+        fill.setColor(INK);
+        c.drawPath(path, fill);
+        // Teeth: a smile stitched across.
+        line.setColor(INK);
+        line.setStrokeWidth(3f * u);
+        float my = cy + 106f * u;
+        path.reset();
+        path.moveTo(cx - 70f * u, my - 6f * u);
+        path.quadTo(cx, my + 12f * u, cx + 70f * u, my - 6f * u);
+        c.drawPath(path, line);
+        line.setStrokeWidth(2.5f * u);
+        for (int i = -5; i <= 5; i++) {
+            float x = cx + i * 12f * u;
+            float y = my + 3f * u * (1f - (i * i) / 25f);
+            c.drawLine(x, y - 15f * u, x, y + 15f * u, line);
+        }
+        // The chin's little flower.
+        drawFlower(c, cx, jaw - 13f * u, 10f * u, PINK, 0xFFFFA8D4, 0xFFC4186E);
+    }
+
+    private void drawAltarCloth(Canvas c, int w, float u) {
+        float rr = w - 28f * u, l = rr - 300f * u, t = 340f * u, b = 548f * u;
+        r.set(l, t, rr, b);
+        fill.setColor(CLOTH);
+        c.drawRoundRect(r, 10f * u, 10f * u, fill);
+        // A fringe of paper colours on top.
+        float seg = (rr - l) / 15f;
+        for (int i = 0; i < 15; i++) {
+            fill.setColor(PAPER[i % PAPER.length]);
+            path.reset();
+            path.moveTo(l + i * seg, t);
+            path.lineTo(l + (i + 1) * seg, t);
+            path.lineTo(l + (i + 0.5f) * seg, t + 13f * u);
+            path.close();
+            c.drawPath(path, fill);
+        }
+    }
+
+    /** The tier the candles stand on. */
+    private void drawCandleStands(Canvas c, float u) {
+        float l = 28f * u, rr = l + 300f * u, b = 548f * u;
+        r.set(l, b - 26f * u, rr, b);
+        fill.setColor(CLOTH);
+        c.drawRoundRect(r, 6f * u, 6f * u, fill);
+        float seg = (rr - l) / 15f;
+        for (int i = 0; i < 15; i++) {
+            fill.setColor(PAPER[i % PAPER.length]);
+            path.reset();
+            path.moveTo(l + i * seg, b - 26f * u);
+            path.lineTo(l + (i + 1) * seg, b - 26f * u);
+            path.lineTo(l + (i + 0.5f) * seg, b - 15f * u);
+            path.close();
+            c.drawPath(path, fill);
+        }
+    }
+
+    // ---------- Papel picado: the battery ----------
+
+    private void drawFlags(Canvas c, int w, float u) {
+        boolean low = v.socPercent != null && v.socPercent < 20f;
+        int lit = Tally.lit(v.socPercent, 10f, FLAGS);
+        float fw = 100f * u, gap = (w - FLAGS * fw) / (FLAGS + 1f);
+        fill.setStyle(Paint.Style.FILL);
+        for (int i = 0; i < FLAGS; i++) {
+            float x = gap + i * (fw + gap);
+            c.save();
+            c.translate(x, 12f * u);
+            // The breeze of driving; still when parked.
+            c.skew((float) Math.sin(time * 2.2f + i * 0.8f) * 0.05f, 0);
+            boolean on = i < lit;
+            fill.setColor(!on ? 0x38FFFFFF : low ? RED : PAPER[i % PAPER.length]);
+            c.drawPath(flag, fill);
+            c.restore();
+        }
+    }
+
+    private void drawBattery(Canvas c, float u) {
+        boolean low = v.socPercent != null && v.socPercent < 20f;
+        float x = 36f * u;
+        label(c, low ? "BATTERY LOW" : "BATTERY", x, 134f * u, 19f * u, low ? RED : GOLD, face, Paint.Align.LEFT);
+        label(c, fmt(v.socPercent, "%.0f %%", "—"), x, 200f * u, 66f * u, low ? RED : BONE, serif, Paint.Align.LEFT);
+    }
+
+    // ---------- The marigold ring: the power ----------
+
+    private void drawRing(Canvas c, float cx, float cy, float u) {
+        float rad = 188f * u, half = marigold.getWidth() / 2f;
+        int lit = Tally.ofPower(v.powerKw, 150f, 50f, PETALS);
+        boolean regen = v.powerKw != null && v.powerKw < 0f;
+        for (int i = 0; i < PETALS; i++) {
+            // Clockwise from the top; regeneration runs the other way.
+            int k = regen ? PETALS - i : i;
+            double a = Math.PI * 2 * k / PETALS - Math.PI / 2;
+            float x = cx + (float) Math.cos(a) * rad, y = cy + (float) Math.sin(a) * rad;
+            boolean on = i < lit;
+            image.setAlpha(on ? 255 : 46);
+            c.drawBitmap(on && regen ? turquoise : marigold, x - half, y - half, image);
+        }
+        image.setAlpha(255);
+        // The power's number on a plate at the foot of the ring.
+        String power = v.powerKw == null ? "— kW" : String.format(Locale.US, regen ? "+%.1f kW" : "%.1f kW",
+                Math.abs(v.powerKw));
+        float py = cy + rad + 2f * u;
+        r.set(cx - 78f * u, py - 22f * u, cx + 78f * u, py + 20f * u);
+        fill.setColor(0xF02C1242);
+        c.drawRoundRect(r, 20f * u, 20f * u, fill);
+        line.setColor(regen ? TURQUOISE : MARIGOLD);
+        line.setStrokeWidth(2f * u);
+        c.drawRoundRect(r, 20f * u, 20f * u, line);
+        label(c, power, cx, py + 10f * u, 28f * u, regen ? TURQUOISE : GOLD, face, Paint.Align.CENTER);
+    }
+
+    private void drawSpeed(Canvas c, float cx, float cy, float u) {
+        label(c, fmt(v.speedKmh, "%.0f", "—"), cx, cy - 66f * u, 74f * u, INK, serif, Paint.Align.CENTER);
+        label(c, "KM/H", cx, cy - 128f * u, 14f * u, 0xFFC4186E, face, Paint.Align.CENTER);
+    }
+
+    // ---------- Candles: the range ----------
+
+    private void drawCandles(Canvas c, float u, boolean moving) {
+        float x0 = 36f * u;
+        label(c, "RANGE", x0, 246f * u, 19f * u, GOLD, face, Paint.Align.LEFT);
+        label(c, fmt(v.rangeKm, "%.0f km", "—"), x0, 298f * u, 48f * u, BONE, serif, Paint.Align.LEFT);
+        int lit = Tally.lit(v.rangeKm, 50f, CANDLES);
+        float base = 522f * u, step = 36f * u;
+        for (int i = 0; i < CANDLES; i++) {
+            float x = x0 + 14f * u + i * step;
+            float tall = (130f - (i % 4) * 22f - (i % 3) * 8f) * u;
+            float top = base - tall;
+            r.set(x - 11f * u, top, x + 11f * u, base);
+            boolean on = i < lit;
+            fill.setColor(on ? WAX : 0x40F4E6C8);
+            c.drawRoundRect(r, 3f * u, 3f * u, fill);
+            // A band of colour.
+            r.set(x - 11f * u, top + tall * 0.55f, x + 11f * u, top + tall * 0.55f + 10f * u);
+            fill.setColor(AccentColor.withAlpha(PAPER[i % PAPER.length], on ? 0xFF : 0x40));
+            c.drawRect(r, fill);
+            // The wick.
+            line.setColor(on ? INK : 0x60FFFFFF);
+            line.setStrokeWidth(2f * u);
+            c.drawLine(x, top, x, top - 6f * u, line);
+            if (!on) continue;
+            // The flame, flickering only while driving, with its halo.
+            float flick = moving ? (float) Math.sin(time * 9f + i * 1.7f) * 2.5f * u : 0f;
+            fill.setColor(0x33FFB84A);
+            c.drawCircle(x, top - 18f * u, 19f * u, fill);
+            path.reset();
+            path.moveTo(x, top - 32f * u - Math.abs(flick));
+            path.quadTo(x + 10f * u + flick, top - 12f * u, x, top - 4f * u);
+            path.quadTo(x - 10f * u + flick, top - 12f * u, x, top - 32f * u - Math.abs(flick));
+            path.close();
+            fill.setColor(FLAME);
+            c.drawPath(path, fill);
+        }
+    }
+
+    // ---------- The petal path: the last two minutes of power ----------
+
+    private void drawPetals(Canvas c, int w, int h, float u) {
+        float base = h - 16f * u, amp = 58f * u;
+        float[] trail = v.powerTrail;
+        // The path itself, faint, whatever the readings.
+        fill.setColor(0x30FF9A1F);
+        r.set(0, base - 4f * u, w, base + 4f * u);
+        c.drawRect(r, fill);
+        if (trail == null || trail.length == 0) return;
+        int n = trail.length;
+        for (int i = 0; i < n; i++) {
+            float p = trail[i];
+            if (Float.isNaN(p)) continue;
+            float x = (i + 0.5f) / n * w;
+            float share = Math.min(1f, Math.abs(p) / (p < 0 ? 40f : 60f));
+            // Each stack of petals rises with the power, each petal tilted its own way.
+            int stack = 1 + Math.round(share * 4f);
+            for (int s = 0; s < stack; s++) {
+                float y = base - s * amp / 4f;
+                c.save();
+                c.rotate(((i * 47 + s * 83) % 180) - 90f, x, y);
+                r.set(x - 8f * u, y - 3.5f * u, x + 8f * u, y + 3.5f * u);
+                fill.setColor(p < 0 ? TURQUOISE : s % 2 == 0 ? MARIGOLD : GOLD);
+                c.drawOval(r, fill);
+                c.restore();
+            }
+        }
+    }
+
+    // ---------- The right side ----------
+
+    /** The clock in a tin frame. */
+    private void drawClock(Canvas c, int w, float u) {
+        float rr = w - 28f * u, l = rr - 300f * u, t = 118f * u, b = 202f * u;
+        r.set(l, t, rr, b);
+        fill.setColor(0xCC160A26);
+        c.drawRoundRect(r, 12f * u, 12f * u, fill);
+        line.setColor(GOLD);
+        line.setStrokeWidth(2.5f * u);
+        c.drawRoundRect(r, 12f * u, 12f * u, line);
+        fill.setColor(GOLD);
+        for (int i = 0; i <= 12; i++) {
+            float x = l + 12f * u + i * (rr - l - 24f * u) / 12f;
+            c.drawCircle(x, t + 8f * u, 2f * u, fill);
+            c.drawCircle(x, b - 8f * u, 2f * u, fill);
+        }
+        label(c, v.clock.isEmpty() ? "—" : v.clock, (l + rr) / 2f, b - 22f * u, 50f * u, BONE, serif, Paint.Align.CENTER);
+    }
+
+    /** P R N D as four small marigolds: the one engaged in bloom. */
+    private void drawGears(Canvas c, int w, float u) {
+        float rr = w - 28f * u, l = rr - 300f * u, y = 270f * u;
+        String[] gears = { "P", "R", "N", "D" };
+        String now = Gear.label(v.gear);
+        float step = (rr - l) / 4f, half = marigold.getWidth() / 2f, scale = 58f * u / marigold.getWidth();
+        for (int i = 0; i < gears.length; i++) {
+            float x = l + (i + 0.5f) * step;
+            boolean on = gears[i].equals(now);
+            if (on) {
+                c.save();
+                c.scale(scale, scale, x, y);
+                c.drawBitmap(marigold, x - half, y - half, image);
+                c.restore();
+            } else {
+                fill.setColor(0x40FFFFFF);
+                c.drawCircle(x, y, 22f * u, fill);
+            }
+            label(c, gears[i], x, y + 11f * u, 30f * u, on ? INK : 0xB0FFFFFF, serif, Paint.Align.CENTER);
+        }
+    }
+
+    /** Trip, usage, climate, odometer on the altar cloth. */
+    private void drawRows(Canvas c, int w, int h, float u) {
+        float rr = w - 28f * u, l = rr - 300f * u, top = 378f * u;
+        String[][] rows = {
+                { "TRIP", fmt(v.tripKm, "%.1f km", "—") },
+                { "5 MIN", fmt(v.usage5Min, "%.1f kWh/100", "—") },
+                { "SINCE START", fmt(v.usageTrip, "%.1f kWh/100", "—") },
+                { "CLIMATE", fmt(v.climateCelsius, "%.0f °C", "—") },
+                { "ODOMETER", fmt(v.odometerKm, "%,.0f km", "—") },
+        };
+        for (int i = 0; i < rows.length; i++) {
+            float y = top + i * 35f * u;
+            label(c, rows[i][0], l + 18f * u, y, 19f * u, GOLD, thin, Paint.Align.LEFT);
+            label(c, rows[i][1], rr - 18f * u, y, 23f * u, BONE, face, Paint.Align.RIGHT);
+        }
+    }
+}

app/src/main/java/com/evsuite/abrp/MusicPulse.java

@@ -0,0 +1,51 @@
+package com.evsuite.abrp;
+
+/**
+ * How strongly the Halloween pumpkin's light answers the music at this moment, from 0 to 1, out of
+ * the kick drum's band the audio analyser reports. What counts is the hit, not the loudness: only
+ * a jump of the bass since the last reading lights it, measured against the biggest jumps of the
+ * last seconds, so quiet and loud songs both flash, and a held bass note or a steady hum does not.
+ * Jumps that are small against the bass's own level (a swelling note, noise) are ignored. It
+ * flares at once and dies down within a beat, as a flame does. No reading or silence falls back to
+ * 0, so without music the light stays as it is. Android-free and unit-tested.
+ */
+final class MusicPulse {
+
+    /** Below this the bass counts as silence. */
+    static final float SILENT = 0.005f;
+    /** The kick drum's band, in Hz, that {@link MusicTap} reads. */
+    static final float FROM_HZ = 40f, TO_HZ = 120f;
+    private static final float FALL_S = 0.2f, AVERAGE_S = 2f, PEAK_S = 4f;
+    /** A jump below this share of the recent biggest one lights nothing. */
+    private static final float THRESHOLD = 0.2f;
+    /** A jump has to be at least this share of the bass's average level to count at all. */
+    private static final float LEVEL_SHARE = 0.5f;
+
+    private float last, average, peakJump, pulse;
+
+    /** One reading, {@code seconds} after the last; null when it failed. Returns the new pulse. */
+    float update(Float bass, float seconds) {
+        float target = 0f;
+        if (bass == null || bass.isNaN() || bass < SILENT) {
+            last = 0f;
+            average = 0f;
+            peakJump = 0f;
+        } else {
+            float jump = Math.max(0f, bass - last);
+            last = bass;
+            average = average == 0f ? bass : average + (bass - average) * share(seconds, AVERAGE_S);
+            peakJump = Math.max(jump, peakJump - peakJump * share(seconds, PEAK_S));
+            float reference = Math.max(peakJump, average * LEVEL_SHARE);
+            if (reference > 0f) {
+                target = Math.max(0f, Math.min(1f, (jump / reference - THRESHOLD) / (1f - THRESHOLD)));
+            }
+        }
+        pulse = target > pulse ? target : pulse + (target - pulse) * share(seconds, FALL_S);
+        if (pulse < 0.005f) pulse = 0f;
+        return pulse;
+    }
+
+    private static float share(float seconds, float timeConstant) {
+        return Math.min(1f, Math.max(0f, seconds) / timeConstant);
+    }
+}

app/src/main/java/com/evsuite/abrp/MusicTap.java

@@ -0,0 +1,91 @@
+package com.evsuite.abrp;
+
+import android.Manifest;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.media.audiofx.Visualizer;
+
+/**
+ * Listens to what the head unit plays for the Halloween pumpkin's light: Android's audio analyser
+ * on the output mix, its kick-drum band read 25 times a second on a thread of its own, made into a
+ * {@link MusicPulse}. Runs only while MainActivity says so (the style on screen, the app in
+ * front, and "Pumpkin light follows the music" on). Levels only: no sound is kept and no microphone used. Where the analyser hears nothing
+ * (the radio) or is not available, the pulse stays 0 and the pumpkin burns as usual.
+ */
+final class MusicTap {
+
+    private static final int READ_MS = 40, GIVE_UP_AFTER_FAILURES = 50;
+
+    private final Context app;
+    private volatile Thread worker;
+    private volatile float pulse;
+
+    MusicTap(Context context) {
+        app = context.getApplicationContext();
+    }
+
+    /** From 0 to 1; safe to read from any thread. */
+    float pulse() {
+        return pulse;
+    }
+
+    void setRunning(boolean run) {
+        if (run == (worker != null)) return;
+        if (!run) {
+            Thread stopping = worker;
+            worker = null;
+            pulse = 0f;
+            stopping.interrupt();
+            return;
+        }
+        if (app.checkSelfPermission(Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) return;
+        Thread thread = new Thread(this::listen, "music-tap");
+        thread.setDaemon(true);
+        worker = thread;
+        thread.start();
+    }
+
+    /** All analyser calls live here, off the main thread; it is always let go. */
+    private void listen() {
+        Thread me = Thread.currentThread();
+        Visualizer analyser = null;
+        try {
+            analyser = new Visualizer(0);
+            analyser.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
+            analyser.setScalingMode(Visualizer.SCALING_MODE_NORMALIZED);
+            if (analyser.setEnabled(true) != Visualizer.SUCCESS) return;
+            int rateHz = analyser.getSamplingRate() / 1000;
+            byte[] fft = new byte[analyser.getCaptureSize()];
+            MusicPulse music = new MusicPulse();
+            long last = System.nanoTime();
+            int failures = 0;
+            while (worker == me && failures < GIVE_UP_AFTER_FAILURES) {
+                Thread.sleep(READ_MS);
+                boolean read = analyser.getFft(fft) == Visualizer.SUCCESS;
+                failures = read ? 0 : failures + 1;
+                long now = System.nanoTime();
+                float value = music.update(read ? SoundLevels.band(fft, rateHz, MusicPulse.FROM_HZ, MusicPulse.TO_HZ) : null, (now - last) / 1e9f);
+                last = now;
+                if (worker == me) pulse = value;
+            }
+        } catch (InterruptedException e) {
+            // Told to stop.
+        } catch (RuntimeException e) {
+            // No analyser here: the pumpkin burns as usual.
+        } finally {
+            if (worker == me) pulse = 0f;
+            if (analyser != null) {
+                try {
+                    analyser.setEnabled(false);
+                } catch (RuntimeException ignored) {
+                    // Released next either way.
+                }
+                try {
+                    analyser.release();
+                } catch (RuntimeException ignored) {
+                    // Nothing more can be done from here.
+                }
+            }
+        }
+    }
+}

app/src/main/java/com/evsuite/abrp/NowPlaying.java

@@ -0,0 +1,136 @@
+package com.evsuite.abrp;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.regex.Pattern;
+
+/**
+ * What the Overview shows as playing, out of the media sessions the head unit publishes
+ * ({@link NowPlayingWatcher}): the session that plays, the one updated last when several do, and
+ * when none plays the one paused last. Sessions without any text are passed over (Bluetooth leaves
+ * an empty one behind when the phone stops). The text is cleaned: CarPlay's YouTube titles lose
+ * their trailing video ID, and the radio, whose title is the station and whose artist field is the
+ * station's own text, shows that text with the station below. Shown on screen only; nothing here
+ * is logged or sent. Android-free and unit-tested.
+ */
+final class NowPlaying {
+
+    enum Source { BLUETOOTH, CARPLAY, RADIO, OTHER }
+
+    /** android.media.session.PlaybackState's codes, mirrored to stay Android-free. */
+    static final int STATE_PAUSED = 2, STATE_PLAYING = 3, STATE_FAST_FORWARDING = 4, STATE_REWINDING = 5,
+            STATE_BUFFERING = 6, STATE_SKIPPING_TO_PREVIOUS = 9, STATE_SKIPPING_TO_NEXT = 10,
+            STATE_SKIPPING_TO_QUEUE_ITEM = 11;
+
+    private static final int MAX_TEXT = 200;
+    /** A YouTube video ID in brackets at the end of a title, as CarPlay passes them on. */
+    private static final Pattern VIDEO_ID = Pattern.compile("\\s*\\[[A-Za-z0-9_-]{11}\\]$");
+    private static final Pattern SPACES = Pattern.compile("\\s+");
+
+    private NowPlaying() {}
+
+    /** One media session as last seen. Times in the platform's elapsed-realtime milliseconds. */
+    static final class Session {
+        String packageName;
+        int state;
+        String title, artist;
+        /** -1 when the session says no position. */
+        long positionMs = -1;
+        long positionUpdatedAt;
+        float speed = 1f;
+        /** 0 when unknown (the radio). */
+        long durationMs;
+        /** A file or content URI for the cover, when the session names one (Bluetooth does). */
+        String artUri;
+    }
+
+    /** What to show. {@code subtitle} may be null; {@code session} is where it came from. */
+    static final class Track {
+        final Source source;
+        final String title, subtitle;
+        final boolean playing;
+        final Session session;
+
+        Track(Source source, String title, String subtitle, boolean playing, Session session) {
+            this.source = source;
+            this.title = title;
+            this.subtitle = subtitle;
+            this.playing = playing;
+            this.session = session;
+        }
+
+        /** Where the song is at {@code now}, or -1 when the session gives no position. */
+        long positionAt(long now) {
+            if (session.positionMs < 0) return -1;
+            long at = session.positionMs;
+            if (playing && session.positionUpdatedAt > 0 && now > session.positionUpdatedAt) {
+                at += (long) ((now - session.positionUpdatedAt) * session.speed);
+            }
+            if (session.durationMs > 0) at = Math.min(at, session.durationMs);
+            return Math.max(0, at);
+        }
+
+        /** How far through the song, from 0 to 1, or -1 without a length or position (the radio). */
+        float progressAt(long now) {
+            long at = positionAt(now);
+            if (at < 0 || session.durationMs <= 0) return -1f;
+            return Math.min(1f, at / (float) session.durationMs);
+        }
+    }
+
+    static Track pick(List<Session> sessions) {
+        Session best = null;
+        boolean bestPlaying = false;
+        if (sessions != null) {
+            for (Session s : sessions) {
+                if (s == null || (!playing(s.state) && s.state != STATE_PAUSED)) continue;
+                if (clean(s.title) == null && clean(s.artist) == null) continue;
+                boolean p = playing(s.state);
+                if (best == null || (p && !bestPlaying)
+                        || (p == bestPlaying && s.positionUpdatedAt > best.positionUpdatedAt)) {
+                    best = s;
+                    bestPlaying = p;
+                }
+            }
+        }
+        if (best == null) return null;
+        Source source = source(best.packageName);
+        String title = clean(best.title), artist = clean(best.artist);
+        if (source == Source.RADIO) {
+            // The station is the title; its own text (song, programme) comes as the artist.
+            if (artist != null) return new Track(source, artist, title, bestPlaying, best);
+            return new Track(source, title, null, bestPlaying, best);
+        }
+        if (title == null) return new Track(source, artist, null, bestPlaying, best);
+        return new Track(source, title, artist, bestPlaying, best);
+    }
+
+    static boolean playing(int state) {
+        switch (state) {
+            case STATE_PLAYING: case STATE_FAST_FORWARDING: case STATE_REWINDING: case STATE_BUFFERING:
+            case STATE_SKIPPING_TO_PREVIOUS: case STATE_SKIPPING_TO_NEXT: case STATE_SKIPPING_TO_QUEUE_ITEM:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    /** Which source a session's app is: the ones seen on the owner's car, the rest as "other". */
+    static Source source(String packageName) {
+        if (packageName == null) return Source.OTHER;
+        String p = packageName.toLowerCase(Locale.ROOT);
+        if (p.equals("com.android.bluetooth")) return Source.BLUETOOTH;
+        if (p.contains("allgo") || p.contains("carplay")) return Source.CARPLAY;
+        if (p.contains("radio")) return Source.RADIO;
+        return Source.OTHER;
+    }
+
+    /** Trimmed, one line, without a trailing video ID, at most 200 characters; null when empty. */
+    static String clean(String text) {
+        if (text == null) return null;
+        String s = SPACES.matcher(text).replaceAll(" ").trim();
+        s = VIDEO_ID.matcher(s).replaceAll("").trim();
+        if (s.isEmpty()) return null;
+        return s.length() > MAX_TEXT ? s.substring(0, MAX_TEXT - 1) + "…" : s;
+    }
+}

app/src/main/java/com/evsuite/abrp/NowPlayingWatcher.java

@@ -0,0 +1,215 @@
+package com.evsuite.abrp;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.media.MediaMetadata;
+import android.media.session.MediaController;
+import android.media.session.MediaSessionManager;
+import android.media.session.PlaybackState;
+import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Watches the media sessions the head unit publishes (Bluetooth's, CarPlay's, the radio's) for the
+ * Overview's "now playing", the way the Logs tab's music-sources check reads them: through
+ * {@code MediaSessionManager}, which needs MEDIA_CONTENT_CONTROL (the car build has it as the
+ * system user). It only listens: no media browser service is connected to (that stopped the music
+ * in 2.42.0) and no command is sent. Each session's state and song are kept as the session reports
+ * changes, so reading {@link #current()} costs no call into another app. Runs only while
+ * MainActivity says so, on the main thread. Without the permission, or on any failure, there is
+ * simply nothing playing. Nothing it sees is logged.
+ */
+final class NowPlayingWatcher {
+
+    private static final int COVER_PX = 160;
+
+    private final Context app;
+    private final Handler main = new Handler(Looper.getMainLooper());
+    private final List<Watched> watched = new ArrayList<>();
+    private final ExecutorService coverLoader = Executors.newSingleThreadExecutor(r -> {
+        Thread t = new Thread(r, "now-playing-cover");
+        t.setDaemon(true);
+        return t;
+    });
+    private MediaSessionManager sessions;
+    private boolean running;
+    private Bitmap sessionCover;
+    /** The file cover asked for last and what came of it, from the loader thread. */
+    private volatile String coverUri;
+    private volatile Bitmap fileCover;
+
+    private final MediaSessionManager.OnActiveSessionsChangedListener changed = this::watch;
+
+    NowPlayingWatcher(Context context) {
+        app = context.getApplicationContext();
+    }
+
+    void setRunning(boolean run) {
+        if (run == running) return;
+        running = run;
+        if (!run) {
+            try {
+                if (sessions != null) sessions.removeOnActiveSessionsChangedListener(changed);
+            } catch (RuntimeException ignored) {
+                // Gone with the listener either way.
+            }
+            watch(null);
+            return;
+        }
+        try {
+            sessions = (MediaSessionManager) app.getSystemService(Context.MEDIA_SESSION_SERVICE);
+            if (sessions == null) return;
+            sessions.addOnActiveSessionsChangedListener(changed, null, main);
+            watch(sessions.getActiveSessions(null));
+        } catch (RuntimeException e) {
+            // No permission (the stable build) or no session service: nothing plays.
+            android.util.Log.w("NowPlaying", "Media sessions not readable: " + e.getClass().getSimpleName());
+        }
+    }
+
+    boolean isRunning() {
+        return running;
+    }
+
+    /** What plays now, or null. */
+    NowPlaying.Track current() {
+        List<NowPlaying.Session> seen = new ArrayList<>(watched.size());
+        for (Watched w : watched) seen.add(w.seen);
+        return NowPlaying.pick(seen);
+    }
+
+    /** The current track's cover, or null: the picture the session carries, else its file, once loaded. */
+    Bitmap cover(NowPlaying.Track track) {
+        if (track == null) return null;
+        for (Watched w : watched) {
+            if (w.seen == track.session && w.cover != null) return w.cover;
+        }
+        String uri = track.session.artUri;
+        if (uri == null) return null;
+        if (!uri.equals(coverUri)) {
+            coverUri = uri;
+            fileCover = null;
+            coverLoader.execute(() -> {
+                Bitmap b = load(uri);
+                if (uri.equals(coverUri)) fileCover = b;
+            });
+        }
+        return fileCover;
+    }
+
+    private void watch(List<MediaController> controllers) {
+        for (Watched w : watched) w.release();
+        watched.clear();
+        if (controllers == null || !running) return;
+        for (MediaController c : controllers) {
+            try {
+                watched.add(new Watched(c));
+            } catch (RuntimeException ignored) {
+                // A session that went away while being read.
+            }
+        }
+    }
+
+    /** One session: its last state and song, kept up to date by its callback. */
+    private final class Watched extends MediaController.Callback {
+        final MediaController controller;
+        final NowPlaying.Session seen = new NowPlaying.Session();
+        Bitmap cover;
+
+        Watched(MediaController c) {
+            controller = c;
+            seen.packageName = c.getPackageName();
+            onPlaybackStateChanged(c.getPlaybackState());
+            onMetadataChanged(c.getMetadata());
+            c.registerCallback(this, main);
+        }
+
+        void release() {
+            try {
+                controller.unregisterCallback(this);
+            } catch (RuntimeException ignored) {
+                // Already gone.
+            }
+        }
+
+        @Override
+        public void onPlaybackStateChanged(PlaybackState state) {
+            seen.state = state == null ? 0 : state.getState();
+            seen.positionMs = state == null ? -1 : state.getPosition();
+            seen.positionUpdatedAt = state == null ? 0 : state.getLastPositionUpdateTime();
+            seen.speed = state == null ? 1f : state.getPlaybackSpeed();
+        }
+
+        @Override
+        public void onMetadataChanged(MediaMetadata m) {
+            seen.title = text(m, MediaMetadata.METADATA_KEY_TITLE);
+            if (seen.title == null) seen.title = text(m, MediaMetadata.METADATA_KEY_DISPLAY_TITLE);
+            seen.artist = text(m, MediaMetadata.METADATA_KEY_ARTIST);
+            if (seen.artist == null) seen.artist = text(m, MediaMetadata.METADATA_KEY_DISPLAY_SUBTITLE);
+            seen.durationMs = m == null ? 0 : Math.max(0, m.getLong(MediaMetadata.METADATA_KEY_DURATION));
+            cover = picture(m);
+            seen.artUri = text(m, MediaMetadata.METADATA_KEY_ALBUM_ART_URI);
+            if (seen.artUri == null) seen.artUri = text(m, MediaMetadata.METADATA_KEY_ART_URI);
+        }
+
+        @Override
+        public void onSessionDestroyed() {
+            seen.state = 0;
+        }
+    }
+
+    private static String text(MediaMetadata m, String key) {
+        if (m == null) return null;
+        try {
+            CharSequence s = m.getText(key);
+            return s == null ? null : s.toString();
+        } catch (RuntimeException e) {
+            return null;
+        }
+    }
+
+    private static Bitmap picture(MediaMetadata m) {
+        if (m == null) return null;
+        for (String key : new String[] { MediaMetadata.METADATA_KEY_ALBUM_ART, MediaMetadata.METADATA_KEY_ART,
+                MediaMetadata.METADATA_KEY_DISPLAY_ICON }) {
+            try {
+                Bitmap b = m.getBitmap(key);
+                if (b != null && b.getWidth() > 1 && b.getHeight() > 1) return b;
+            } catch (RuntimeException ignored) {
+                // Try the next.
+            }
+        }
+        return null;
+    }
+
+    /** A cover file, made small; null when it cannot be read. Off the main thread. */
+    private Bitmap load(String uri) {
+        try {
+            Uri u = uri.startsWith("/") ? Uri.fromFile(new java.io.File(uri)) : Uri.parse(uri);
+            String scheme = u.getScheme();
+            if (!"file".equals(scheme) && !"content".equals(scheme)) return null;
+            BitmapFactory.Options size = new BitmapFactory.Options();
+            size.inJustDecodeBounds = true;
+            try (InputStream in = app.getContentResolver().openInputStream(u)) {
+                BitmapFactory.decodeStream(in, null, size);
+            }
+            if (size.outWidth <= 0 || size.outHeight <= 0) return null;
+            BitmapFactory.Options small = new BitmapFactory.Options();
+            small.inSampleSize = 1;
+            while (Math.max(size.outWidth, size.outHeight) / (small.inSampleSize * 2) >= COVER_PX) small.inSampleSize *= 2;
+            try (InputStream in = app.getContentResolver().openInputStream(u)) {
+                return BitmapFactory.decodeStream(in, null, small);
+            }
+        } catch (Exception | OutOfMemoryError e) {
+            return null;
+        }
+    }
+}

app/src/main/java/com/evsuite/abrp/OverviewStyle.java

@@ -31,7 +31,9 @@ enum OverviewStyle {
     TIME_CIRCUITS(false, false),
     QUEST(false, false),
     VISOR(true, true),
-    EMPIRE(false, false);
+    EMPIRE(false, false),
+    MUERTOS(false, false),
+    HALLOWEEN(false, false);
 
     static final String PREF_KEY = "overview_style";
 

app/src/main/java/com/evsuite/abrp/ServerHttp.java

@@ -59,6 +59,12 @@ final class ServerHttp {
      */
     static Response send(String method, String url, String authorization, String contentType, byte[] body)
             throws Exception {
+        return send(method, url, authorization, contentType, null, body);
+    }
+
+    /** As above, with a {@code Content-Encoding} ({@code "gzip"}) for the body, or null. */
+    static Response send(String method, String url, String authorization, String contentType,
+            String contentEncoding, byte[] body) throws Exception {
         HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
         try {
             connection.setRequestMethod(method);
@@ -69,6 +75,7 @@ final class ServerHttp {
                 connection.setDoOutput(true);
                 connection.setFixedLengthStreamingMode(body.length);
                 connection.setRequestProperty("Content-Type", contentType);
+                if (contentEncoding != null) connection.setRequestProperty("Content-Encoding", contentEncoding);
                 try (OutputStream out = connection.getOutputStream()) { out.write(body); }
             }
             int status = connection.getResponseCode();

app/src/main/java/com/evsuite/abrp/SignalRecorder.java

@@ -7,6 +7,8 @@ import android.content.IntentFilter;
 import android.os.Bundle;
 import android.os.Environment;
 
+import com.evsuite.hardware.AssistBlock;
+import com.evsuite.hardware.EVHardware;
 import com.evsuite.hardware.probe.VendorSurfaceProbe;
 
 import java.io.File;
@@ -26,15 +28,19 @@ import java.util.Map;
  * The signal recorder on the Logs tab: for {@link #DURATION_MS} it reads every value the
  * head unit offers (`VendorSurfaceProbe.capture`: every CarPropertyManager property and every
  * value getter of the vendor objects, read only) again and again, and every steering-wheel key
- * the head unit reports, into a {@link SignalRecording}. The driver notes the times they do
+ * the head unit reports, into a {@link SignalRecording}. It also listens, as the head unit's own
+ * driver-assistance manager does, to the properties of the assistance block
+ * ({@link AssistBlock}): subscribed for change events the whole time, because a value that is
+ * only filled while someone listens reads as its default when polled (2.40.3, still the
+ * cruise control). The driver notes the times they do
  * what is to be found; the values that change then are the leads. (Built to find the adaptive
  * cruise control, 2.32.0: on SWI68 the head unit gets none of it, see SPECS.md.)
  *
  * A full capture is far heavier than the Overview's reading, so the next one waits at least
  * {@link #MIN_INTERVAL_MS} and at least as long as the last one took: the recorder uses at most
  * half the time. It runs on its own thread, on after the app leaves the screen (the service
- * keeps the process), and stops by itself. At the end the recording goes to the app's storage
+ * keeps the process), and stops by itself. At the end the recording goes to the app's storage,
- * and to the app's folder on every USB stick plugged in.
+ * to the app's folder on every USB stick plugged in, and to the car server ({@link LogOutbox}).
  */
 final class SignalRecorder {
 
@@ -85,6 +91,22 @@ final class SignalRecorder {
         } catch (RuntimeException ignored) {
             // No key reports: the properties are recorded all the same.
         }
+        EVHardware.PropertyListening listening = null;
+        try {
+            listening = EVHardware.INSTANCE.listenToProperties(AssistBlock.INSTANCE::contains,
+                    (id, area, value) -> {
+                        rec.event(System.currentTimeMillis(),
+                                String.format(Locale.US, "CPM 0x%08X/%d", id, area), value);
+                        return kotlin.Unit.INSTANCE;
+                    });
+        } catch (Throwable t) {
+            rec.note(System.currentTimeMillis(), "listening failed: " + t.getClass().getSimpleName());
+        }
+        rec.note(System.currentTimeMillis(), listening == null
+                ? "listening to the assistance properties: not possible ("
+                        + EVHardware.INSTANCE.getListenProblem() + ")"
+                : "listening to " + listening.getSubscribed() + " assistance properties ("
+                        + listening.getRefused() + " refused)");
         try {
             long end = startedMs + DURATION_MS;
             while (running && System.currentTimeMillis() < end) {
@@ -99,6 +121,13 @@ final class SignalRecorder {
         } catch (Throwable t) {
             rec.note(System.currentTimeMillis(), "recorder stopped: " + t.getClass().getSimpleName());
         } finally {
+            if (listening != null) {
+                try {
+                    listening.close();
+                } catch (Throwable ignored) {
+                    // the car service is gone
+                }
+            }
             if (keysRegistered) {
                 try {
                     app.unregisterReceiver(keys);
@@ -130,15 +159,27 @@ final class SignalRecorder {
         text.add("Steering-wheel keys and notes:");
         text.addAll(rec.notes());
         text.add("");
-        text.add("Changed values, the rarest first:");
+        text.add("Assistance properties heard (" + rec.events() + " change events), changing ones first:");
+        text.addAll(rec.heard());
+        text.add("");
+        text.add("Changed values (polled), the rarest first:");
         text.addAll(rec.summary());
         text.add("");
         text.add("Everything, in order:");
         text.addAll(rec.lines());
-        List<String> places = new ArrayList<>();
-        if (write(new File(app.getFilesDir(), FILE), text)) places.add("app");
         String name = "signal-recording-" + new SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
                 .format(new Date(startedMs)) + ".txt";
+        return saveCopies(app, FILE, name, text);
+    }
+
+    /**
+     * Writes a report to the app's storage ({@code appFile}), to the app's folder on every USB
+     * stick plugged in ({@code name}) and to the car server; says where it went. Shared with
+     * {@link MediaProbe}.
+     */
+    static String saveCopies(Context app, String appFile, String name, List<String> text) {
+        List<String> places = new ArrayList<>();
+        if (write(new File(app.getFilesDir(), appFile), text)) places.add("app");
         File[] dirs = app.getExternalFilesDirs(null);
         for (File dir : dirs == null ? new File[0] : dirs) {
             try {
@@ -149,6 +190,12 @@ final class SignalRecorder {
                 // A volume that cannot say what it is gets nothing.
             }
         }
+        // And to the server, so it reaches the owner without a stick; the service sends it again
+        // later when the car is offline now.
+        if (LogOutbox.add(app, name, text)) {
+            LogOutbox.send(app);
+            places.add("for the server");
+        }
         return places.isEmpty() ? "not saved" : "saved: " + String.join(", ", places);
     }
 
@@ -168,14 +215,19 @@ final class SignalRecorder {
         long elapsed = (running ? System.currentTimeMillis() : startedMs + DURATION_MS) - startedMs;
         if (running) {
             out.add(context.getString(R.string.signal_recorder_running, elapsed / 60_000, (elapsed / 1000) % 60,
-                    recording.captures()));
+                    recording.captures(), recording.events()));
         } else {
             out.add(context.getString(R.string.signal_recorder_done, SignalRecording.time(startedMs),
-                    recording.captures(), result == null ? "…" : result));
+                    recording.captures(), recording.events(), result == null ? "…" : result));
+            String sent = LogOutbox.status(context);
+            if (sent != null) out.add(sent);
         }
         // Steering-wheel keys and the like first: few, and each one a lead.
         List<String> notes = recording.notes();
         out.addAll(notes.subList(Math.max(0, notes.size() - 10), notes.size()));
+        // Then what the listening heard, changing properties first.
+        List<String> heard = recording.heard();
+        for (String line : heard.subList(0, Math.min(12, heard.size()))) out.add("heard " + line);
         out.addAll(recording.summary());
         return out;
     }

app/src/main/java/com/evsuite/abrp/SignalRecording.java

@@ -16,6 +16,10 @@ import java.util.TreeSet;
  * feature on and off, changes a setting). It keeps what changed, when, and per value how
  * often and through which values, so the value that follows the action stands out: it
  * changes a few times, at the moments the driver noted.
+ *
+ * Besides the captures (polled), it keeps the change events of the properties the recorder
+ * listens to ({@link #event}): how many per property and through which values. A value the
+ * head unit only fills while someone listens shows up there and nowhere else.
  * Pure Java, unit-tested.
  */
 final class SignalRecording {
@@ -31,6 +35,10 @@ final class SignalRecording {
     private final List<String> notes = new ArrayList<>();
     private final Map<String, Integer> changes = new HashMap<>();
     private final Map<String, LinkedHashSet<String>> seen = new HashMap<>();
+    private int events;
+    private final Map<String, String> lastEvent = new HashMap<>();
+    private final Map<String, Integer> eventCounts = new HashMap<>();
+    private final Map<String, LinkedHashSet<String>> eventValues = new HashMap<>();
 
     static String time(long ms) {
         return new SimpleDateFormat("HH:mm:ss", Locale.US).format(new Date(ms));
@@ -65,6 +73,45 @@ final class SignalRecording {
         notes.add(time(ms) + "  " + what);
     }
 
+    /**
+     * A change event from a property listened to. Every one is counted; the timeline gets a
+     * line only when the value differs from that property's last event.
+     */
+    synchronized void event(long ms, String key, String value) {
+        events++;
+        eventCounts.merge(key, 1, Integer::sum);
+        String before = lastEvent.put(key, value);
+        if (value.equals(before)) return;
+        lines.add(time(ms) + "  heard " + key + " = " + value);
+        LinkedHashSet<String> values = eventValues.computeIfAbsent(key, k -> new LinkedHashSet<>());
+        if (values.size() < VALUES_KEPT) values.add(shorten(value));
+    }
+
+    synchronized int events() {
+        return events;
+    }
+
+    /**
+     * Every property that sent events: first those that sent different values, the fewest
+     * events first (the leads), then those that only ever repeated one value.
+     */
+    synchronized List<String> heard() {
+        List<String> keys = new ArrayList<>(eventCounts.keySet());
+        keys.sort((a, b) -> {
+            boolean va = eventValues.get(a).size() > 1, vb = eventValues.get(b).size() > 1;
+            if (va != vb) return va ? -1 : 1;
+            int c = Integer.compare(eventCounts.get(a), eventCounts.get(b));
+            return c != 0 ? c : a.compareTo(b);
+        });
+        List<String> out = new ArrayList<>();
+        for (String key : keys) {
+            LinkedHashSet<String> values = eventValues.get(key);
+            out.add(key + "  " + eventCounts.get(key) + " events  " + String.join(" → ", values)
+                    + (values.size() >= VALUES_KEPT ? " …" : ""));
+        }
+        return out;
+    }
+
     /** The notes alone, in order. */
     synchronized List<String> notes() {
         return new ArrayList<>(notes);

app/src/main/java/com/evsuite/abrp/SoundLevels.java

@@ -0,0 +1,108 @@
+package com.evsuite.abrp;
+
+import java.util.Locale;
+
+/**
+ * What {@link SoundProbe} makes of Android's audio analyser: how loud a captured waveform is, how
+ * strong a band of its spectrum, and whether a run of those looks like music the analyser can
+ * hear. A failed read is null, never a silent 0. Android-free and unit-tested.
+ */
+final class SoundLevels {
+
+    /** Below this the peak counts as silence (the 8-bit waveform's noise is about 1/128). */
+    static final float SILENT = 0.02f;
+
+    private SoundLevels() {}
+
+    /** The waveform's peak from 0 to 1. Its samples are unsigned 8-bit, with silence at 128. */
+    static Float peak(byte[] wave) {
+        if (wave == null || wave.length == 0) return null;
+        int max = 0;
+        for (byte b : wave) max = Math.max(max, Math.abs((b & 0xFF) - 128));
+        return Math.min(1f, max / 128f);
+    }
+
+    /**
+     * The mean strength from 0 to 1 of the bins between {@code fromHz} and {@code toHz}. The
+     * analyser's FFT holds the DC and Nyquist values first, then each bin's real and imaginary
+     * part, signed; a bin {@code k} is {@code k × rate / length} Hz.
+     */
+    static Float band(byte[] fft, int rateHz, float fromHz, float toHz) {
+        if (fft == null || fft.length < 4 || rateHz <= 0) return null;
+        float sum = 0f;
+        int bins = 0;
+        for (int k = 1; k < fft.length / 2; k++) {
+            float hz = k * (float) rateHz / fft.length;
+            if (hz < fromHz || hz >= toHz) continue;
+            sum += (float) Math.hypot(fft[2 * k], fft[2 * k + 1]) / 128f;
+            bins++;
+        }
+        return bins == 0 ? null : Math.min(1f, sum / bins);
+    }
+
+    enum Verdict {
+        /** The analyser gave no readings at all. */
+        NO_READING,
+        /** Nothing was playing and the analyser heard nothing: says nothing about the source. */
+        NOTHING_PLAYING,
+        /** Something played and the analyser heard silence: it cannot hear this source. */
+        DEAF,
+        /** The level stays where it is: not music, or not real data. */
+        STEADY,
+        /** The level moves: the pumpkin could follow it. */
+        HEARS
+    }
+
+    /** Readings gathered over a time. */
+    static final class Summary {
+        private int samples, readings, bandReadings;
+        private float peakMin = Float.MAX_VALUE, peakMax, bass, mid, treble;
+        private Integer rms;
+
+        /** One round of reads, each null when it failed. */
+        void add(Float peak, Float bassBand, Float midBand, Float trebleBand, Integer rmsMilliBel) {
+            samples++;
+            if (peak != null) {
+                readings++;
+                peakMin = Math.min(peakMin, peak);
+                peakMax = Math.max(peakMax, peak);
+            }
+            if (bassBand != null && midBand != null && trebleBand != null) {
+                bandReadings++;
+                bass += bassBand;
+                mid += midBand;
+                treble += trebleBand;
+            }
+            if (rmsMilliBel != null) rms = rmsMilliBel;
+        }
+
+        Verdict verdict(boolean somethingPlays) {
+            if (readings == 0) return Verdict.NO_READING;
+            if (peakMax < SILENT) return somethingPlays ? Verdict.DEAF : Verdict.NOTHING_PLAYING;
+            return peakMax - peakMin < SILENT ? Verdict.STEADY : Verdict.HEARS;
+        }
+
+        /** One line of the report; what could not be read is "—". */
+        String line() {
+            return "peak " + (readings == 0 ? "—" : String.format(Locale.US, "%.2f–%.2f", peakMin, peakMax))
+                    + ", bass " + mean(bass) + ", mid " + mean(mid) + ", treble " + mean(treble)
+                    + ", rms " + (rms == null ? "—" : rms + " mB")
+                    + " (" + readings + "/" + samples + ")";
+        }
+
+        private String mean(float sum) {
+            return bandReadings == 0 ? "—" : String.format(Locale.US, "%.3f", sum / bandReadings);
+        }
+    }
+
+    /** The report's last line. */
+    static String words(Verdict verdict) {
+        switch (verdict) {
+            case HEARS: return "Result: the analyser hears it, and the level moves.";
+            case STEADY: return "Result: the level does not move, so this is not usable music.";
+            case DEAF: return "Result: something plays, but the analyser hears silence.";
+            case NOTHING_PLAYING: return "Result: nothing was playing, so this says nothing. Play something and check again.";
+            default: return "Result: the analyser gave no readings.";
+        }
+    }
+}

app/src/main/java/com/evsuite/abrp/SoundProbe.java

@@ -0,0 +1,179 @@
+package com.evsuite.abrp;
+
+import android.Manifest;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.media.AudioManager;
+import android.media.audiofx.Visualizer;
+import android.media.session.MediaController;
+import android.media.session.MediaSessionManager;
+import android.media.session.PlaybackState;
+
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * The sound check on the Logs tab: whether Android's audio analyser ({@link Visualizer} on the
+ * output mix, session 0) can hear what the head unit plays, before the Halloween pumpkin's light
+ * follows the music. Only one tap starts it, and it listens for {@value #SECONDS} seconds and lets
+ * go. It records levels only, never the sound, and uses no microphone. The report goes where a
+ * signal recording goes ({@link SignalRecorder#saveCopies}): the app, a USB stick, the server.
+ */
+final class SoundProbe {
+
+    static final String FILE = "sound_probe.txt";
+    private static final int SECONDS = 10, READS_PER_SECOND = 10;
+
+    private static volatile boolean running;
+    private static long startedMs;
+    private static List<String> report = new ArrayList<>();
+    private static String result;
+
+    private SoundProbe() {}
+
+    static synchronized boolean running() {
+        return running;
+    }
+
+    static synchronized void start(Context context) {
+        if (running) return;
+        Context app = context.getApplicationContext();
+        running = true;
+        startedMs = System.currentTimeMillis();
+        result = null;
+        report = new ArrayList<>();
+        new Thread(() -> probe(app), "sound-probe").start();
+    }
+
+    private static void probe(Context app) {
+        List<String> out = new ArrayList<>();
+        out.add("Sound probe, " + SignalRecording.time(startedMs) + ", app " + BuildConfig.VERSION_NAME);
+        String saved;
+        try {
+            permission(app, Manifest.permission.RECORD_AUDIO, out);
+            permission(app, Manifest.permission.MODIFY_AUDIO_SETTINGS, out);
+            boolean plays = sessions(app, out);
+            plays |= musicActive(app, out);
+            SoundLevels.Summary all = listen(out);
+            plays |= musicActive(app, out);
+            out.add("");
+            out.add(SoundLevels.words(all.verdict(plays)));
+        } catch (Throwable t) {
+            out.add("probe stopped: " + t.getClass().getSimpleName());
+        } finally {
+            String name = "sound-probe-" + new SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+                    .format(new Date(startedMs)) + ".txt";
+            saved = SignalRecorder.saveCopies(app, FILE, name, out);
+            synchronized (SoundProbe.class) {
+                report = out;
+                result = saved;
+                running = false;
+            }
+        }
+    }
+
+    private static void permission(Context app, String name, List<String> out) {
+        boolean granted = app.checkSelfPermission(name) == PackageManager.PERMISSION_GRANTED;
+        out.add(name.substring(name.lastIndexOf('.') + 1) + ": " + (granted ? "granted" : "not granted"));
+    }
+
+    private static boolean musicActive(Context app, List<String> out) {
+        try {
+            AudioManager am = (AudioManager) app.getSystemService(Context.AUDIO_SERVICE);
+            boolean active = am != null && am.isMusicActive();
+            out.add("music active: " + active);
+            return active;
+        } catch (RuntimeException e) {
+            out.add("music active: unreadable (" + e.getClass().getSimpleName() + ")");
+            return false;
+        }
+    }
+
+    /** Which source is playing, for reading the report later; no song. True when one is. */
+    private static boolean sessions(Context app, List<String> out) {
+        boolean playing = false;
+        try {
+            MediaSessionManager msm = (MediaSessionManager) app.getSystemService(Context.MEDIA_SESSION_SERVICE);
+            List<MediaController> controllers = msm == null ? null : msm.getActiveSessions(null);
+            if (controllers == null || controllers.isEmpty()) out.add("sessions: none");
+            else for (MediaController c : controllers) {
+                PlaybackState s = c.getPlaybackState();
+                out.add("session: " + MediaProbeText.clean(c.getPackageName()) + ", "
+                        + (s == null ? "no state" : MediaProbeText.playbackState(s.getState())));
+                if (s != null && s.getState() == PlaybackState.STATE_PLAYING) playing = true;
+            }
+        } catch (Throwable t) {
+            out.add("sessions: not readable (" + t.getClass().getSimpleName() + ")");
+        }
+        return playing;
+    }
+
+    /** Listens for the whole time, one report line a second; always lets the analyser go. */
+    private static SoundLevels.Summary listen(List<String> out) throws InterruptedException {
+        SoundLevels.Summary all = new SoundLevels.Summary();
+        Visualizer analyser = null;
+        try {
+            analyser = new Visualizer(0);
+            int[] sizes = Visualizer.getCaptureSizeRange();
+            int code = analyser.setCaptureSize(sizes[1]);
+            analyser.setScalingMode(Visualizer.SCALING_MODE_NORMALIZED);
+            analyser.setMeasurementMode(Visualizer.MEASUREMENT_MODE_PEAK_RMS);
+            int enabled = analyser.setEnabled(true);
+            int size = analyser.getCaptureSize(), rateHz = analyser.getSamplingRate() / 1000;
+            out.add("analyser: capture " + size + " at " + rateHz + " Hz, set size " + code + ", enable " + enabled);
+            if (enabled != Visualizer.SUCCESS) return all;
+            byte[] wave = new byte[size], fft = new byte[size];
+            Visualizer.MeasurementPeakRms measure = new Visualizer.MeasurementPeakRms();
+            for (int second = 0; second < SECONDS; second++) {
+                SoundLevels.Summary now = new SoundLevels.Summary();
+                for (int read = 0; read < READS_PER_SECOND; read++) {
+                    Thread.sleep(1000 / READS_PER_SECOND);
+                    Float peak = analyser.getWaveForm(wave) == Visualizer.SUCCESS ? SoundLevels.peak(wave) : null;
+                    boolean spectrum = analyser.getFft(fft) == Visualizer.SUCCESS;
+                    Float bass = spectrum ? SoundLevels.band(fft, rateHz, 20f, 250f) : null;
+                    Float mid = spectrum ? SoundLevels.band(fft, rateHz, 250f, 2000f) : null;
+                    Float treble = spectrum ? SoundLevels.band(fft, rateHz, 2000f, 16000f) : null;
+                    Integer rms = analyser.getMeasurementPeakRms(measure) == Visualizer.SUCCESS ? measure.mRms : null;
+                    now.add(peak, bass, mid, treble, rms);
+                    all.add(peak, bass, mid, treble, rms);
+                }
+                out.add(MediaProbeText.duration(second * 1000L) + "  " + now.line());
+            }
+        } catch (RuntimeException e) {
+            out.add("analyser not available: " + e.getClass().getSimpleName() + " " + MediaProbeText.clean(e.getMessage()));
+        } finally {
+            if (analyser != null) {
+                try {
+                    analyser.setEnabled(false);
+                } catch (RuntimeException ignored) {
+                    // Released next either way.
+                }
+                try {
+                    analyser.release();
+                } catch (RuntimeException e) {
+                    out.add("analyser not released: " + e.getClass().getSimpleName());
+                }
+            }
+        }
+        return all;
+    }
+
+    /** What the Logs tab shows: the state, then the report. */
+    static synchronized List<String> status(Context context) {
+        List<String> lines = new ArrayList<>();
+        if (startedMs == 0) return lines;
+        if (running) {
+            lines.add(context.getString(R.string.sound_probe_running));
+            return lines;
+        }
+        lines.add(context.getString(R.string.media_probe_done, SignalRecording.time(startedMs),
+                result == null ? "…" : result));
+        String sent = LogOutbox.status(context);
+        if (sent != null) lines.add(sent);
+        lines.addAll(report.subList(Math.min(1, report.size()), report.size()));
+        return lines;
+    }
+}

app/src/main/java/com/evsuite/abrp/StylePalette.java

@@ -24,6 +24,8 @@ final class StylePalette {
             case QUEST: return R.style.ThemeOverlay_EV_Style_Quest;
             case VISOR: return R.style.ThemeOverlay_EV_Style_Visor;
             case EMPIRE: return R.style.ThemeOverlay_EV_Style_Empire;
+            case MUERTOS: return R.style.ThemeOverlay_EV_Style_Muertos;
+            case HALLOWEEN: return R.style.ThemeOverlay_EV_Style_Halloween;
             default: return 0;
         }
     }

app/src/main/java/com/evsuite/abrp/Tally.java

@@ -0,0 +1,27 @@
+package com.evsuite.abrp;
+
+/**
+ * How many of a row of things a value lights: flags, candles, petals, embers, bats. An unread
+ * value lights none, never a made-up amount. Android-free and unit-tested.
+ */
+final class Tally {
+
+    private Tally() {}
+
+    /** One thing per {@code step} of the value, rounded, from 0 to {@code max}; null or NaN is 0. */
+    static int lit(Float value, float step, int max) {
+        if (value == null || value.isNaN() || step <= 0f || value <= 0f) return 0;
+        return Math.min(max, Math.round(value / step));
+    }
+
+    /**
+     * Of {@code count} things round a gauge, how many the power lights: all of them at
+     * {@code fullDraw} kW drawn, or at {@code fullRegen} kW regenerated (negative power).
+     * Any real power lights at least one, so the gauge never looks idle while it is not.
+     */
+    static int ofPower(Float kw, float fullDraw, float fullRegen, int count) {
+        if (kw == null || kw.isNaN() || Math.abs(kw) < 0.1f) return 0;
+        float share = Math.abs(kw) / (kw < 0f ? fullRegen : fullDraw);
+        return Math.max(1, Math.min(count, Math.round(share * count)));
+    }
+}

app/src/main/java/com/evsuite/abrp/UpdateDiagnosis.java

@@ -0,0 +1,69 @@
+package com.evsuite.abrp;
+
+import java.io.IOException;
+import java.net.ConnectException;
+import java.net.NoRouteToHostException;
+import java.net.SocketException;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.net.ssl.SSLException;
+
+/**
+ * Why an update check failed, in words for the update log, and what the car's networks look
+ * like. Built from an error's type and an HTTP status only, because an error's own text can carry
+ * the server's address: nothing here holds a URL or a credential. Android-free and unit-tested.
+ */
+final class UpdateDiagnosis {
+
+    private static final Pattern STATUS = Pattern.compile("^Release API returned (\\d{3})$");
+
+    private UpdateDiagnosis() {}
+
+    /** One line about a failed step. */
+    static String failure(Throwable t) {
+        if (t == null) return "unknown failure";
+        String type = " (" + t.getClass().getSimpleName() + ")";
+        if (t instanceof UnknownHostException) return "the name could not be looked up: no data connection, or no name service" + type;
+        if (t instanceof SocketTimeoutException) return "no answer in time: a very slow or blocked connection" + type;
+        if (t instanceof ConnectException || t instanceof NoRouteToHostException) return "no connection could be made" + type;
+        if (t instanceof SSLException) return "the secure connection failed: something in between may have answered, or the head unit's clock is wrong" + type;
+        if (t instanceof SocketException) return "the connection broke off" + type;
+        if (t instanceof IOException && t.getMessage() != null) {
+            Matcher status = STATUS.matcher(t.getMessage());
+            if (status.matches()) return status(Integer.parseInt(status.group(1)));
+            if (t.getMessage().equals("Invalid release response")) return "the answer was not a list of releases";
+        }
+        return "failed" + type;
+    }
+
+    /** What a status from the car server means here. */
+    static String status(int code) {
+        String what;
+        if (code >= 300 && code < 400) what = "something in between redirected it, as a SIM without data may";
+        else if (code == 401 || code == 403) what = "the server refuses the car's token";
+        else if (code == 404) what = "the server does not know this address";
+        else if (code >= 500) what = "the server or the forge behind it has a problem";
+        else what = "not what was expected";
+        return "the server answered HTTP " + code + ": " + what;
+    }
+
+    /** The outside-world test: a 204 is the internet working; anything else stands in between. */
+    static String internet(int code) {
+        if (code == 204) return "the internet works (HTTP 204)";
+        return "something in between answered HTTP " + code + " instead, as a SIM without data may";
+    }
+
+    /** One network as Android sees it. */
+    static String network(List<String> transports, boolean internet, boolean validated,
+                          boolean active, boolean roaming) {
+        return (transports.isEmpty() ? "unknown type" : String.join("+", transports))
+                + (active ? ", in use" : "")
+                + (internet ? ", offers internet" : ", no internet")
+                + (validated ? ", confirmed by Android" : ", not confirmed by Android")
+                + (roaming ? ", roaming" : "");
+    }
+}

app/src/main/java/com/evsuite/abrp/UpdateLog.java

@@ -21,7 +21,7 @@ import java.util.Locale;
  */
 final class UpdateLog {
 
-    static final int MAX_LINES = 10;
+    static final int MAX_LINES = 40;
     private static final String PREFS = "update_log";
     private static final String KEY = "lines";
     private static final String KEY_VERSION = "version";

app/src/main/res/layout-w1000dp/pane_settings.xml

@@ -26,6 +26,12 @@
                     </LinearLayout>
                 </LinearLayout>
                 <TextView android:id="@+id/accent_note" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="4dp" android:textAppearance="@style/Text.EV.Secondary" android:visibility="gone" />
+                <!-- Only the styles that show what plays (Tiles, Halloween). -->
+                <com.google.android.material.switchmaterial.SwitchMaterial android:id="@+id/now_playing_switch" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="72dp" android:text="@string/label_now_playing" android:textAppearance="@style/Text.EV.Body" android:paddingTop="8dp" android:paddingBottom="8dp" app:useMaterialThemeColors="true" app:thumbTint="@color/switch_thumb" app:trackTint="@color/switch_track" android:textColor="@color/ev_text_primary" android:visibility="gone" />
+                <TextView android:id="@+id/now_playing_hint" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/hint_now_playing" android:textAppearance="@style/Text.EV.Secondary" android:visibility="gone" />
+                <!-- Only Halloween listens to the music. -->
+                <com.google.android.material.switchmaterial.SwitchMaterial android:id="@+id/music_light_switch" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="72dp" android:text="@string/label_music_light" android:textAppearance="@style/Text.EV.Body" android:paddingTop="8dp" android:paddingBottom="8dp" app:useMaterialThemeColors="true" app:thumbTint="@color/switch_thumb" app:trackTint="@color/switch_track" android:textColor="@color/ev_text_primary" android:visibility="gone" />
+                <TextView android:id="@+id/music_light_hint" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/hint_music_light" android:textAppearance="@style/Text.EV.Secondary" android:visibility="gone" />
                 <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:baselineAligned="false">
                     <LinearLayout android:layout_width="0dp" android:layout_weight="1" android:layout_height="wrap_content" android:layout_marginEnd="12dp" android:orientation="vertical">
                         <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_tire_unit" android:textAppearance="@style/Text.EV.Body" android:layout_marginTop="8dp" />

app/src/main/res/layout-w1000dp/pane_vehicle.xml

@@ -31,7 +31,18 @@
             </LinearLayout>
         </LinearLayout>
         <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:orientation="horizontal" android:baselineAligned="false">
-            <Space android:layout_width="0dp" android:layout_height="1dp" android:layout_weight="1" android:layout_marginEnd="10dp" />
+            <!-- What plays (NowPlaying), in the slot under the battery; invisible when nothing does. -->
+            <LinearLayout android:id="@+id/now_playing_tile" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginEnd="10dp" android:orientation="vertical" android:minHeight="112dp" android:padding="16dp" android:background="@drawable/bg_glass" android:visibility="invisible">
+                <TextView android:id="@+id/now_playing_source" android:layout_width="match_parent" android:layout_height="wrap_content" android:textAppearance="@style/Text.EV.Secondary" android:maxLines="1" android:ellipsize="end" />
+                <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="4dp" android:orientation="horizontal" android:gravity="center_vertical" android:baselineAligned="false">
+                    <ImageView android:id="@+id/now_playing_cover" android:layout_width="44dp" android:layout_height="44dp" android:layout_marginEnd="10dp" android:scaleType="centerCrop" android:importantForAccessibility="no" android:visibility="gone" />
+                    <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:orientation="vertical">
+                        <TextView android:id="@+id/now_playing_title" android:layout_width="match_parent" android:layout_height="wrap_content" android:textAppearance="@style/Text.EV.Body" android:textSize="17sp" android:maxLines="1" android:ellipsize="end" />
+                        <TextView android:id="@+id/now_playing_artist" android:layout_width="match_parent" android:layout_height="wrap_content" android:textAppearance="@style/Text.EV.Secondary" android:textColor="?attr/evAccentLight" android:textSize="16sp" android:maxLines="1" android:ellipsize="end" />
+                    </LinearLayout>
+                </LinearLayout>
+                <ProgressBar android:id="@+id/now_playing_progress" style="?android:attr/progressBarStyleHorizontal" android:layout_width="match_parent" android:layout_height="4dp" android:layout_marginTop="6dp" android:max="1000" android:progressTint="?attr/evAccent" android:progressBackgroundTint="?attr/evAccentTrack" android:visibility="invisible" />
+            </LinearLayout>
             <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:layout_marginEnd="10dp" android:orientation="vertical" android:minHeight="112dp" android:padding="16dp" android:background="@drawable/bg_glass">
                 <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/vehicle_row_energy_trip" android:textAppearance="@style/Text.EV.Secondary" />
                 <TextView android:id="@+id/vehicle_energy_trip" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/no_value" android:layout_marginTop="6dp" android:textAppearance="@style/Text.EV.Metric.Compact" android:gravity="end" android:fontFeatureSettings="tnum" android:maxLines="1" android:autoSizeTextType="uniform" android:autoSizeMinTextSize="18sp" android:autoSizeMaxTextSize="28sp" android:autoSizeStepGranularity="1sp" />

app/src/main/res/layout/pane_log.xml

@@ -8,6 +8,20 @@
             <com.google.android.material.button.MaterialButton android:id="@+id/signal_record_button" android:layout_width="match_parent" android:layout_height="72dp" android:layout_marginTop="16dp" android:text="@string/btn_signal_record" style="@style/Widget.EV.Button.Outlined" />
             <TextView android:id="@+id/signal_record_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:textAppearance="@style/Text.EV.Body" android:fontFamily="monospace" android:textSize="17sp" android:lineSpacingExtra="8dp" android:textIsSelectable="true" android:visibility="gone" />
         </LinearLayout>
+        <!-- The music-sources check (MediaProbe): where the head unit tells what is playing. -->
+        <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:paddingStart="24dp" android:paddingEnd="24dp" android:paddingTop="16dp" android:paddingBottom="16dp" android:layout_marginBottom="16dp" android:background="@drawable/bg_glass">
+            <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_media_probe" android:textAppearance="@style/Text.EV.Eyebrow" />
+            <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="12dp" android:text="@string/media_probe_hint" android:textAppearance="@style/Text.EV.Secondary" />
+            <com.google.android.material.button.MaterialButton android:id="@+id/media_probe_button" android:layout_width="match_parent" android:layout_height="72dp" android:layout_marginTop="16dp" android:text="@string/btn_media_probe" style="@style/Widget.EV.Button.Outlined" />
+            <TextView android:id="@+id/media_probe_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:textAppearance="@style/Text.EV.Body" android:fontFamily="monospace" android:textSize="17sp" android:lineSpacingExtra="8dp" android:textIsSelectable="true" android:visibility="gone" />
+        </LinearLayout>
+        <!-- The sound check (SoundProbe): whether the audio analyser can hear what plays. -->
+        <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:paddingStart="24dp" android:paddingEnd="24dp" android:paddingTop="16dp" android:paddingBottom="16dp" android:layout_marginBottom="16dp" android:background="@drawable/bg_glass">
+            <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_sound_probe" android:textAppearance="@style/Text.EV.Eyebrow" />
+            <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="12dp" android:text="@string/sound_probe_hint" android:textAppearance="@style/Text.EV.Secondary" />
+            <com.google.android.material.button.MaterialButton android:id="@+id/sound_probe_button" android:layout_width="match_parent" android:layout_height="72dp" android:layout_marginTop="16dp" android:text="@string/btn_sound_probe" style="@style/Widget.EV.Button.Outlined" />
+            <TextView android:id="@+id/sound_probe_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:textAppearance="@style/Text.EV.Body" android:fontFamily="monospace" android:textSize="17sp" android:lineSpacingExtra="8dp" android:textIsSelectable="true" android:visibility="gone" />
+        </LinearLayout>
         <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:paddingStart="24dp" android:paddingEnd="24dp" android:paddingTop="16dp" android:paddingBottom="16dp" android:background="@drawable/bg_glass">
             <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_call_log" android:textAppearance="@style/Text.EV.Eyebrow" />
             <com.google.android.material.button.MaterialButton android:id="@+id/flush_now_button" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:text="@string/btn_flush_now" app:icon="@drawable/ic_refresh" app:iconGravity="textStart" style="@style/Widget.EV.Button.Outlined" />

app/src/main/res/layout/pane_settings.xml

@@ -17,6 +17,12 @@
                 <com.google.android.material.textfield.MaterialAutoCompleteTextView android:id="@+id/accent_choices" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="72dp" android:inputType="none" android:textSize="20sp" app:simpleItemLayout="@layout/dropdown_item" />
             </com.google.android.material.textfield.TextInputLayout>
             <TextView android:id="@+id/accent_note" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="4dp" android:textAppearance="@style/Text.EV.Secondary" android:visibility="gone" />
+            <!-- Only the styles that show what plays (Tiles, Halloween). -->
+            <com.google.android.material.switchmaterial.SwitchMaterial android:id="@+id/now_playing_switch" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="72dp" android:text="@string/label_now_playing" android:textAppearance="@style/Text.EV.Body" android:paddingTop="8dp" android:paddingBottom="8dp" app:useMaterialThemeColors="true" app:thumbTint="@color/switch_thumb" app:trackTint="@color/switch_track" android:textColor="@color/ev_text_primary" android:visibility="gone" />
+            <TextView android:id="@+id/now_playing_hint" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/hint_now_playing" android:textAppearance="@style/Text.EV.Secondary" android:visibility="gone" />
+            <!-- Only Halloween listens to the music. -->
+            <com.google.android.material.switchmaterial.SwitchMaterial android:id="@+id/music_light_switch" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="72dp" android:text="@string/label_music_light" android:textAppearance="@style/Text.EV.Body" android:paddingTop="8dp" android:paddingBottom="8dp" app:useMaterialThemeColors="true" app:thumbTint="@color/switch_thumb" app:trackTint="@color/switch_track" android:textColor="@color/ev_text_primary" android:visibility="gone" />
+            <TextView android:id="@+id/music_light_hint" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/hint_music_light" android:textAppearance="@style/Text.EV.Secondary" android:visibility="gone" />
             <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_tire_unit" android:textAppearance="@style/Text.EV.Body" android:layout_marginTop="20dp" />
             <com.google.android.material.textfield.TextInputLayout style="@style/Widget.EV.Dropdown" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="12dp">
                 <com.google.android.material.textfield.MaterialAutoCompleteTextView android:id="@+id/tire_unit_choices" android:layout_width="match_parent" android:layout_height="wrap_content" android:minHeight="72dp" android:inputType="none" android:textSize="20sp" app:simpleItemLayout="@layout/dropdown_item" />

app/src/main/res/values/strings.xml

@@ -129,6 +129,15 @@
     <string name="overview_style_scifi">Sci-fi</string>
     <string name="overview_style_cartoon">Cartoon</string>
     <string name="overview_style_mg">MG</string>
+    <string name="label_now_playing">Show what\'s playing</string>
+    <string name="hint_now_playing">Title and artist from Bluetooth, CarPlay or the radio. Shown here only, never sent.</string>
+    <string name="now_playing_bluetooth">Bluetooth</string>
+    <string name="now_playing_carplay">CarPlay</string>
+    <string name="now_playing_radio">Radio</string>
+    <string name="now_playing_other">Media</string>
+    <string name="now_playing_paused">%1$s · paused</string>
+    <string name="label_music_light">Pumpkin light follows the music</string>
+    <string name="hint_music_light">Flares on the kick drum over Bluetooth or CarPlay, not the radio. Levels only, no sound kept.</string>
     <string name="accent_not_used">%1$s has its own colours, and the app takes them on. To change the accent colour, pick a style that uses it.</string>
     <string name="overview_fullscreen_enter">Overview full screen: hide the navigation</string>
     <string name="overview_fullscreen_exit">Show the navigation again</string>
@@ -141,6 +150,8 @@
     <string name="overview_style_quest">Quest</string>
     <string name="overview_style_visor">Visor</string>
     <string name="overview_style_empire">Empire</string>
+    <string name="overview_style_muertos">Día de Muertos</string>
+    <string name="overview_style_halloween">Halloween</string>
     <string name="overview_style_nixie">Nixie tubes</string>
     <string name="overview_style_chronograph">Chronograph</string>
     <string name="cockpit_battery">BATTERY</string>
@@ -223,11 +234,22 @@
     <string name="drive_mode_unreadable">Not changed: speed or gear unreadable.</string>
     <string name="drive_mode_unknown">an unknown mode (%1$s)</string>
     <string name="label_signal_recorder">Signal recorder</string>
-    <string name="signal_recorder_hint">Records every value the head unit offers for 3 minutes, plus the steering-wheel keys it reports, and lists what changed, the rarest first. To find a signal: start it, note the times you switch the feature on and off or change it, and look for the values that changed then. With a USB stick plugged in, the whole recording is saved on it too (Android/data/…/files).</string>
+    <string name="signal_recorder_hint">Records every value the head unit offers for 3 minutes, listens to the driver-assistance properties for every change they report, and notes the steering-wheel keys; then lists what changed, the rarest first. To find a signal: start it, note the times you switch the feature on and off or change it, and look for the values that changed then. The whole recording goes to your server (later, if the car is offline), and with a USB stick plugged in it is saved on it too (Android/data/…/files).</string>
     <string name="btn_signal_record">Record 3 minutes</string>
     <string name="btn_signal_stop">Stop recording</string>
-    <string name="signal_recorder_running">Recording: %1$d:%2$02d of 3:00, %3$d captures. Keys reported, then values changed so far, the rarest first:</string>
+    <string name="signal_recorder_running">Recording: %1$d:%2$02d of 3:00, %3$d captures, %4$d change events heard. Keys reported, then assistance properties heard, then values changed so far, the rarest first:</string>
-    <string name="signal_recorder_done">Recording from %1$s: %2$d captures, %3$s. Keys reported, then values changed, the rarest first:</string>
+    <string name="signal_recorder_done">Recording from %1$s: %2$d captures, %3$d change events heard, %4$s. Keys reported, then assistance properties heard, then values changed, the rarest first:</string>
+    <string name="label_media_probe">Music sources</string>
+    <string name="media_probe_hint">Finds where the head unit tells what is playing: the playback Android reports and the media sessions apps publish (CarPlay, Bluetooth, radio, USB), each with its song, and the head unit\'s media services by name. Play something first and check once for each source. Like a recording, the result goes to your server and to a USB stick. It only reads and connects to no other app: nothing is played, paused or skipped.</string>
+    <string name="btn_media_probe">Check music sources</string>
+    <string name="label_sound_probe">Sound check</string>
+    <string name="sound_probe_hint">Finds out whether the app can hear the music, for a light that follows it. Park first, play something, then check once each for Bluetooth, CarPlay and radio. It listens for 10 seconds and keeps only the levels, never the sound, and uses no microphone. Like a recording, the result goes to your server and to a USB stick.</string>
+    <string name="btn_sound_probe">Check sound</string>
+    <string name="sound_probe_running">Listening… (10 seconds)</string>
+    <string name="media_probe_running">Checking… (up to a minute)</string>
+    <string name="media_probe_done">Check from %1$s, %2$s:</string>
+    <string name="log_outbox_sent">Sent to the server.</string>
+    <string name="log_outbox_waiting">Not on the server yet (%1$d waiting: %2$s); it is sent again every 2 minutes.</string>
     <string name="call_log_empty">No upload attempted yet.</string>
     <string name="update_log_title">Updates, newest first:</string>
     <string name="btn_flush_now">Upload now</string>

app/src/main/res/values/style_palettes.xml

@@ -104,4 +104,24 @@
         <item name="evAccentStroke">#80344A99</item>
         <item name="evAccentTrack">#2A3F82</item>
     </style>
+    <!-- Día de Muertos: the pink of the papel picado. -->
+    <style name="ThemeOverlay.EV.Style.Muertos" parent="">
+        <item name="evAccent">#FF2E93</item>
+        <item name="evOnAccent">#22041A</item>
+        <item name="evAccentLight">#FFA8D4</item>
+        <item name="evAccentDeep">#4A0E32</item>
+        <item name="evAccentSurface">#2C1242</item>
+        <item name="evAccentStroke">#80993366</item>
+        <item name="evAccentTrack">#7A2558</item>
+    </style>
+    <!-- Halloween: the pumpkin's orange. -->
+    <style name="ThemeOverlay.EV.Style.Halloween" parent="">
+        <item name="evAccent">#FF8C1A</item>
+        <item name="evOnAccent">#1F0E02</item>
+        <item name="evAccentLight">#FFC27A</item>
+        <item name="evAccentDeep">#3D2008</item>
+        <item name="evAccentSurface">#22102E</item>
+        <item name="evAccentStroke">#80804A1E</item>
+        <item name="evAccentTrack">#6A3F18</item>
+    </style>
 </resources>

app/src/test/java/com/evsuite/abrp/LogOutboxTest.java

@@ -0,0 +1,45 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+public class LogOutboxTest {
+
+    @Test
+    public void whatTheServerSaysDecidesTheFile() {
+        assertEquals(LogOutbox.Outcome.SENT, LogOutbox.outcome(204));
+        assertEquals(LogOutbox.Outcome.SENT, LogOutbox.outcome(200));
+        // Worth another try: no answer, not paired yet, a server without logs yet, busy, broken.
+        for (int status : new int[] {0, 401, 404, 408, 429, 500, 502, 503}) {
+            assertEquals(String.valueOf(status), LogOutbox.Outcome.KEEP, LogOutbox.outcome(status));
+        }
+        // Refused for good: it would never pass.
+        for (int status : new int[] {400, 403, 413, 415}) {
+            assertEquals(String.valueOf(status), LogOutbox.Outcome.DROP, LogOutbox.outcome(status));
+        }
+    }
+
+    @Test
+    public void namesAreTheServersKind() {
+        assertTrue(LogOutbox.validName("signal-recording-20261027-085240.txt"));
+        assertFalse(LogOutbox.validName("signal-recording-20261027-085240.txt.tmp"));
+        assertFalse(LogOutbox.validName("../escape.txt"));
+        assertFalse(LogOutbox.validName("Upper.txt"));
+        assertFalse(LogOutbox.validName(null));
+    }
+
+    @Test
+    public void theOldestGoBeyondTheLimit() {
+        assertEquals(Arrays.asList("signal-recording-20261027-084921.txt"),
+                LogOutbox.surplus(Arrays.asList("signal-recording-20261027-085240.txt",
+                        "signal-recording-20261027-084921.txt", "signal-recording-20261027-090000.txt"), 2));
+        assertEquals(Collections.emptyList(),
+                LogOutbox.surplus(Collections.singletonList("signal-recording-20261027-085240.txt"), 2));
+    }
+}

app/src/test/java/com/evsuite/abrp/MediaProbeTextTest.java

@@ -0,0 +1,38 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class MediaProbeTextTest {
+
+    @Test
+    public void anotherAppsTextStaysOnOneLine() {
+        assertEquals("Song Title", MediaProbeText.clean("Song\nTitle"));
+        assertEquals("(none)", MediaProbeText.clean(null));
+        assertEquals("(empty)", MediaProbeText.clean(" \t"));
+        String longText = new String(new char[500]).replace('\0', 'a');
+        String cleaned = MediaProbeText.clean(longText);
+        assertEquals(MediaProbeText.MAX_TEXT + 1, cleaned.length());
+        assertTrue(cleaned.endsWith("…"));
+    }
+
+    @Test
+    public void androidsNumbersHaveNames() {
+        assertEquals("playing", MediaProbeText.playbackState(3));
+        assertEquals("paused", MediaProbeText.playbackState(2));
+        assertEquals("state 99", MediaProbeText.playbackState(99));
+        assertEquals("media", MediaProbeText.usage(1));
+        assertEquals("navigation guidance", MediaProbeText.usage(12));
+        assertEquals("assistant", MediaProbeText.usage(16));
+        assertEquals("started", MediaProbeText.playerState(2));
+    }
+
+    @Test
+    public void durationsAsMinutes() {
+        assertEquals("3:25", MediaProbeText.duration(205_400));
+        assertEquals("0:00", MediaProbeText.duration(0));
+        assertEquals("?", MediaProbeText.duration(-1));
+    }
+}

app/src/test/java/com/evsuite/abrp/MusicPulseTest.java

@@ -0,0 +1,110 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class MusicPulseTest {
+
+    private static final float STEP = 0.04f;
+
+    @Test
+    public void noReadingAndSilenceLightNothing() {
+        MusicPulse p = new MusicPulse();
+        assertEquals(0f, p.update(null, STEP), 0f);
+        assertEquals(0f, p.update(Float.NaN, STEP), 0f);
+        assertEquals(0f, p.update(0f, STEP), 0f);
+    }
+
+    @Test
+    public void aBeatLightsAndFadesSlowerThanItRises() {
+        MusicPulse p = new MusicPulse();
+        for (int i = 0; i < 50; i++) p.update(0.05f, STEP);
+        float beat = p.update(0.5f, STEP);
+        assertTrue("a beat lights it, got " + beat, beat > 0.8f);
+        float after = p.update(0.05f, STEP);
+        assertTrue("it fades, got " + after, after < beat);
+        assertTrue("slowly, got " + after, after > beat * 0.7f);
+    }
+
+    @Test
+    public void aSteadyHumSettlesAtNothing() {
+        MusicPulse p = new MusicPulse();
+        float last = 1f;
+        for (int i = 0; i < 400; i++) last = p.update(0.3f, STEP);
+        assertEquals(0f, last, 0f);
+    }
+
+    @Test
+    public void aHeldBassNoteLightsOnlyItsStart() {
+        MusicPulse p = new MusicPulse();
+        for (int i = 0; i < 50; i++) p.update(0.05f, STEP);
+        assertTrue(p.update(0.4f, STEP) > 0.8f);
+        float last = 1f;
+        for (int i = 0; i < 25; i++) last = p.update(0.4f, STEP);
+        assertEquals(0f, last, 0f);
+    }
+
+    @Test
+    public void aWobblingBassLineStaysDark() {
+        MusicPulse p = new MusicPulse();
+        for (int i = 0; i < 50; i++) p.update(0.3f, STEP);
+        float top = 0f;
+        for (int i = 0; i < 200; i++) top = Math.max(top, p.update(i % 3 == 0 ? 0.33f : 0.3f, STEP));
+        assertEquals(0f, top, 0f);
+    }
+
+    @Test
+    public void aSwellingNoteStaysDark() {
+        MusicPulse p = new MusicPulse();
+        for (int i = 0; i < 50; i++) p.update(0.1f, STEP);
+        float top = 0f;
+        for (int i = 0; i < 100; i++) top = Math.max(top, p.update(0.1f + i * 0.004f, STEP));
+        assertEquals(0f, top, 0f);
+    }
+
+    @Test
+    public void aKickOverABassLineLights() {
+        MusicPulse p = new MusicPulse();
+        float top = 0f;
+        for (int i = 0; i < 300; i++) {
+            float v = p.update(i % 12 == 0 ? 0.6f : (i % 3 == 0 ? 0.33f : 0.3f), STEP);
+            if (i > 100) top = Math.max(top, v);
+        }
+        assertTrue("a kick lights it, got " + top, top > 0.8f);
+    }
+
+    @Test
+    public void quietAndLoudSongsPulseAlike() {
+        assertEquals(beatOf(0.5f), beatOf(0.05f), 0.02f);
+    }
+
+    private static float beatOf(float scale) {
+        MusicPulse p = new MusicPulse();
+        float top = 0f;
+        for (int i = 0; i < 500; i++) {
+            top = Math.max(top * 0.99f, p.update(i % 12 == 0 ? scale : scale * 0.2f, STEP));
+        }
+        return top;
+    }
+
+    @Test
+    public void whenTheMusicStopsItGoesOut() {
+        MusicPulse p = new MusicPulse();
+        for (int i = 0; i < 100; i++) p.update(i % 12 == 0 ? 0.5f : 0.1f, STEP);
+        float last = 1f;
+        for (int i = 0; i < 100; i++) last = p.update(null, STEP);
+        assertEquals(0f, last, 0f);
+    }
+
+    @Test
+    public void itStaysBetweenZeroAndOne() {
+        MusicPulse p = new MusicPulse();
+        for (int i = 0; i < 2000; i++) {
+            Float bass = i % 11 == 0 ? null : Float.valueOf(i % 7 == 0 ? 1f : 0.1f);
+            float v = p.update(bass, i % 5 == 0 ? 2f : STEP);
+            assertTrue(v >= 0f && v <= 1f);
+        }
+    }
+}

app/src/test/java/com/evsuite/abrp/NowPlayingTest.java

@@ -0,0 +1,138 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+import org.junit.Test;
+
+public class NowPlayingTest {
+
+    private static NowPlaying.Session session(String pkg, int state, String title, String artist, long updatedAt) {
+        NowPlaying.Session s = new NowPlaying.Session();
+        s.packageName = pkg;
+        s.state = state;
+        s.title = title;
+        s.artist = artist;
+        s.positionUpdatedAt = updatedAt;
+        return s;
+    }
+
+    @Test
+    public void nothingToShow() {
+        assertNull(NowPlaying.pick(null));
+        assertNull(NowPlaying.pick(Collections.emptyList()));
+        // Bluetooth's empty session after the phone stopped, and one that only connects.
+        assertNull(NowPlaying.pick(Arrays.asList(
+                session("com.android.bluetooth", 1, "", "", 5),
+                session("com.android.car.radio", 8, "Radio", null, 6),
+                session("com.android.bluetooth", NowPlaying.STATE_PLAYING, " ", null, 7))));
+    }
+
+    @Test
+    public void whatPlaysWinsOverWhatIsPaused() {
+        // As on the car on 2026-10-28: CarPlay paused, Bluetooth playing.
+        NowPlaying.Track t = NowPlaying.pick(Arrays.asList(
+                session("com.allgo.remoteui.mediabrowserservice", NowPlaying.STATE_PAUSED, "A Mix", "Bass Bangers", 900),
+                session("com.android.bluetooth", NowPlaying.STATE_PLAYING, "Paramount", "Mark Petrie & Andrew Prahlow", 100)));
+        assertEquals(NowPlaying.Source.BLUETOOTH, t.source);
+        assertEquals("Paramount", t.title);
+        assertEquals("Mark Petrie & Andrew Prahlow", t.subtitle);
+        assertTrue(t.playing);
+    }
+
+    @Test
+    public void ofTwoPlayingTheNewerWins() {
+        NowPlaying.Track t = NowPlaying.pick(Arrays.asList(
+                session("com.android.bluetooth", NowPlaying.STATE_PLAYING, "Old", null, 100),
+                session("com.allgo.remoteui.mediabrowserservice", NowPlaying.STATE_BUFFERING, "New", null, 200)));
+        assertEquals(NowPlaying.Source.CARPLAY, t.source);
+        assertEquals("New", t.title);
+    }
+
+    @Test
+    public void withNothingPlayingThePausedOneShows() {
+        NowPlaying.Track t = NowPlaying.pick(Arrays.asList(
+                session("com.android.bluetooth", NowPlaying.STATE_PAUSED, "Earlier", null, 100),
+                session("com.allgo.remoteui.mediabrowserservice", NowPlaying.STATE_PAUSED, "Later", null, 300)));
+        assertEquals("Later", t.title);
+        assertFalse(t.playing);
+    }
+
+    @Test
+    public void theRadioShowsItsTextWithTheStationBelow() {
+        NowPlaying.Track t = NowPlaying.pick(Collections.singletonList(
+                session("com.saicmotor.radio", NowPlaying.STATE_PLAYING, "Brillux Radio", "BLIND MELON - NO RAIN", 1)));
+        assertEquals(NowPlaying.Source.RADIO, t.source);
+        assertEquals("BLIND MELON - NO RAIN", t.title);
+        assertEquals("Brillux Radio", t.subtitle);
+        NowPlaying.Track station = NowPlaying.pick(Collections.singletonList(
+                session("com.saicmotor.radio", NowPlaying.STATE_PLAYING, "Brillux Radio", "", 1)));
+        assertEquals("Brillux Radio", station.title);
+        assertNull(station.subtitle);
+        assertEquals(-1f, station.progressAt(5), 0f);
+    }
+
+    @Test
+    public void textIsCleaned() {
+        assertEquals("A Letter to the Past (A Seasonal Feels Mix) Ft. Porter Robinson & Friends By SAINT",
+                NowPlaying.clean("A Letter to the Past (A Seasonal Feels Mix) Ft. Porter Robinson & Friends By SAINT [X4nayMeMBuQ]"));
+        assertEquals("Live [Remastered 2011]", NowPlaying.clean("Live [Remastered 2011]"));
+        assertEquals("two lines", NowPlaying.clean("  two\n  lines "));
+        assertNull(NowPlaying.clean("   "));
+        assertNull(NowPlaying.clean(null));
+        StringBuilder longText = new StringBuilder();
+        for (int i = 0; i < 300; i++) longText.append('x');
+        assertEquals(200, NowPlaying.clean(longText.toString()).length());
+    }
+
+    @Test
+    public void onlyAnArtistStillShows() {
+        NowPlaying.Track t = NowPlaying.pick(Collections.singletonList(
+                session("com.example.player", NowPlaying.STATE_PLAYING, null, "Someone", 1)));
+        assertEquals(NowPlaying.Source.OTHER, t.source);
+        assertEquals("Someone", t.title);
+        assertNull(t.subtitle);
+    }
+
+    @Test
+    public void thePositionRunsOnWhilePlayingAndStopsAtTheEnd() {
+        NowPlaying.Session s = session("com.android.bluetooth", NowPlaying.STATE_PLAYING, "Paramount", "M", 10_000);
+        s.positionMs = 3_000;
+        s.durationMs = 215_000;
+        NowPlaying.Track t = NowPlaying.pick(Collections.singletonList(s));
+        assertEquals(3_000, t.positionAt(10_000));
+        assertEquals(8_000, t.positionAt(15_000));
+        assertEquals(215_000, t.positionAt(10_000_000));
+        assertEquals(1f, t.progressAt(10_000_000), 0f);
+        assertEquals(8_000 / 215_000f, t.progressAt(15_000), 1e-6f);
+    }
+
+    @Test
+    public void aPausedPositionStaysPut() {
+        NowPlaying.Session s = session("com.android.bluetooth", NowPlaying.STATE_PAUSED, "Paramount", null, 10_000);
+        s.positionMs = 3_000;
+        s.durationMs = 215_000;
+        assertEquals(3_000, NowPlaying.pick(Collections.singletonList(s)).positionAt(99_000));
+    }
+
+    @Test
+    public void noPositionNoBar() {
+        NowPlaying.Session s = session("com.android.bluetooth", NowPlaying.STATE_PLAYING, "Paramount", null, 10_000);
+        s.durationMs = 215_000;
+        assertEquals(-1f, NowPlaying.pick(Collections.singletonList(s)).progressAt(20_000), 0f);
+    }
+
+    @Test
+    public void sourcesAreKnownByTheirApps() {
+        assertEquals(NowPlaying.Source.BLUETOOTH, NowPlaying.source("com.android.bluetooth"));
+        assertEquals(NowPlaying.Source.CARPLAY, NowPlaying.source("com.allgo.remoteui.mediabrowserservice"));
+        assertEquals(NowPlaying.Source.RADIO, NowPlaying.source("com.saicmotor.radio"));
+        assertEquals(NowPlaying.Source.OTHER, NowPlaying.source("com.android.music"));
+        assertEquals(NowPlaying.Source.OTHER, NowPlaying.source(null));
+    }
+}

app/src/test/java/com/evsuite/abrp/SignalRecordingTest.java

@@ -63,4 +63,22 @@ public class SignalRecordingTest {
         assertTrue(r.lines().get(4).endsWith("key 287 down"));
         assertEquals(1, r.notes().size());
     }
+
+    @Test
+    public void heardPropertiesWithChangingValuesComeFirst() {
+        SignalRecording r = new SignalRecording();
+        for (int i = 0; i < 5; i++) r.event(i * 1000, "CPM 0x2140A10A/0", "1"); // repeats one value
+        r.event(1000, "CPM 0x2160A15B/0", "0.0");
+        r.event(2000, "CPM 0x2160A15B/0", "101.0");
+        r.event(3000, "CPM 0x2160A15B/0", "101.0");
+        r.event(4000, "CPM 0x2160A15B/0", "90.0");
+        List<String> heard = r.heard();
+        assertEquals(2, heard.size());
+        assertEquals("CPM 0x2160A15B/0  4 events  0.0 → 101.0 → 90.0", heard.get(0));
+        assertEquals("CPM 0x2140A10A/0  5 events  1", heard.get(1));
+        assertEquals(9, r.events());
+        // The timeline holds only the changes: 0.0, 101.0, 90.0 and the first 1.
+        long lines = r.lines().stream().filter(l -> l.contains("heard ")).count();
+        assertEquals(4, lines);
+    }
 }

app/src/test/java/com/evsuite/abrp/SoundLevelsTest.java

@@ -0,0 +1,78 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import org.junit.Test;
+
+public class SoundLevelsTest {
+
+    private static byte[] wave(int... unsigned) {
+        byte[] out = new byte[unsigned.length];
+        for (int i = 0; i < out.length; i++) out[i] = (byte) unsigned[i];
+        return out;
+    }
+
+    @Test
+    public void silenceIsTheMiddleOfTheWaveform() {
+        assertEquals(0f, SoundLevels.peak(wave(128, 128, 128)), 0f);
+        assertEquals(0.5f, SoundLevels.peak(wave(128, 192, 128)), 0f);
+        assertEquals(0.5f, SoundLevels.peak(wave(128, 64, 128)), 0f);
+        assertEquals(1f, SoundLevels.peak(wave(0, 255)), 0f);
+    }
+
+    @Test
+    public void aFailedReadIsNotSilence() {
+        assertNull(SoundLevels.peak(null));
+        assertNull(SoundLevels.peak(new byte[0]));
+        assertNull(SoundLevels.band(null, 48000, 0f, 250f));
+        assertNull(SoundLevels.band(new byte[8], 0, 0f, 250f));
+    }
+
+    @Test
+    public void aBandAveragesItsOwnBins() {
+        // Eight values: DC and Nyquist, then bins 1 to 3, here 1000, 2000 and 3000 Hz.
+        byte[] fft = { 99, 99, 64, 0, 0, 32, 3, 4 };
+        assertEquals(0.5f, SoundLevels.band(fft, 8000, 500f, 1500f), 1e-6f);
+        assertEquals(0.25f, SoundLevels.band(fft, 8000, 2000f, 2500f), 1e-6f);
+        assertEquals(5f / 128f, SoundLevels.band(fft, 8000, 3000f, 4000f), 1e-6f);
+        assertEquals((0.5f + 0.25f) / 2f, SoundLevels.band(fft, 8000, 500f, 2500f), 1e-6f);
+        assertNull(SoundLevels.band(fft, 8000, 5000f, 6000f));
+    }
+
+    @Test
+    public void theVerdictTellsDeafFromNothingPlaying() {
+        SoundLevels.Summary none = new SoundLevels.Summary();
+        none.add(null, null, null, null, null);
+        assertEquals(SoundLevels.Verdict.NO_READING, none.verdict(true));
+
+        SoundLevels.Summary silent = new SoundLevels.Summary();
+        silent.add(0f, 0f, 0f, 0f, -9600);
+        silent.add(0.01f, 0f, 0f, 0f, -9600);
+        assertEquals(SoundLevels.Verdict.DEAF, silent.verdict(true));
+        assertEquals(SoundLevels.Verdict.NOTHING_PLAYING, silent.verdict(false));
+    }
+
+    @Test
+    public void onlyAMovingLevelIsHeard() {
+        SoundLevels.Summary steady = new SoundLevels.Summary();
+        steady.add(0.4f, 0.1f, 0.1f, 0.1f, -2000);
+        steady.add(0.41f, 0.1f, 0.1f, 0.1f, -2000);
+        assertEquals(SoundLevels.Verdict.STEADY, steady.verdict(true));
+
+        SoundLevels.Summary music = new SoundLevels.Summary();
+        music.add(0.1f, 0.2f, 0.1f, 0f, -3000);
+        music.add(0.6f, 0.4f, 0.3f, 0.1f, -1500);
+        assertEquals(SoundLevels.Verdict.HEARS, music.verdict(true));
+    }
+
+    @Test
+    public void theLineAveragesAndMarksWhatFailed() {
+        SoundLevels.Summary s = new SoundLevels.Summary();
+        s.add(0.1f, 0.2f, 0.1f, 0f, -3000);
+        s.add(null, null, null, null, null);
+        s.add(0.6f, 0.4f, 0.3f, 0.1f, -1500);
+        assertEquals("peak 0.10–0.60, bass 0.300, mid 0.200, treble 0.050, rms -1500 mB (2/3)", s.line());
+        assertEquals("peak —, bass —, mid —, treble —, rms — (0/0)", new SoundLevels.Summary().line());
+    }
+}

app/src/test/java/com/evsuite/abrp/TallyTest.java

@@ -0,0 +1,41 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class TallyTest {
+
+    @Test
+    public void anUnreadValueLightsNothing() {
+        assertEquals(0, Tally.lit(null, 10f, 10));
+        assertEquals(0, Tally.lit(Float.NaN, 10f, 10));
+        assertEquals(0, Tally.ofPower(null, 150f, 50f, 24));
+        assertEquals(0, Tally.ofPower(Float.NaN, 150f, 50f, 24));
+    }
+
+    @Test
+    public void oneThingPerStepUpToTheRow() {
+        assertEquals(8, Tally.lit(76f, 10f, 10));
+        assertEquals(10, Tally.lit(100f, 10f, 10));
+        assertEquals(8, Tally.lit(900f, 50f, 8));
+        assertEquals(6, Tally.lit(312f, 50f, 8));
+        assertEquals(0, Tally.lit(0f, 10f, 10));
+        assertEquals(0, Tally.lit(-5f, 10f, 10));
+    }
+
+    @Test
+    public void powerFillsTheGaugeEachWay() {
+        assertEquals(0, Tally.ofPower(0f, 150f, 50f, 24));
+        assertEquals(24, Tally.ofPower(150f, 150f, 50f, 24));
+        assertEquals(24, Tally.ofPower(400f, 150f, 50f, 24));
+        assertEquals(12, Tally.ofPower(-25f, 150f, 50f, 24));
+        assertEquals(24, Tally.ofPower(-50f, 150f, 50f, 24));
+    }
+
+    @Test
+    public void realPowerAlwaysShows() {
+        assertEquals(1, Tally.ofPower(0.5f, 150f, 50f, 24));
+        assertEquals(1, Tally.ofPower(-0.2f, 150f, 50f, 24));
+    }
+}

app/src/test/java/com/evsuite/abrp/UpdateDiagnosisTest.java

@@ -0,0 +1,67 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.ConnectException;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.Collections;
+
+import javax.net.ssl.SSLHandshakeException;
+
+public class UpdateDiagnosisTest {
+
+    @Test
+    public void errorsAreToldApart() {
+        assertTrue(UpdateDiagnosis.failure(new UnknownHostException()).contains("no data connection"));
+        assertTrue(UpdateDiagnosis.failure(new SocketTimeoutException()).contains("in time"));
+        assertTrue(UpdateDiagnosis.failure(new ConnectException()).contains("no connection"));
+        assertTrue(UpdateDiagnosis.failure(new SSLHandshakeException("x")).contains("in between"));
+        assertTrue(UpdateDiagnosis.failure(new IOException("Release API returned 401")).contains("token"));
+        assertTrue(UpdateDiagnosis.failure(new IOException("Invalid release response")).contains("not a list"));
+        assertEquals("unknown failure", UpdateDiagnosis.failure(null));
+    }
+
+    @Test
+    public void anErrorsOwnTextNeverReachesTheLog() {
+        String secret = "https://car.example.com/v1/app/releases?token=abc";
+        for (Throwable t : Arrays.asList(new UnknownHostException(secret), new SocketTimeoutException(secret),
+                new ConnectException(secret), new SSLHandshakeException(secret), new IOException(secret),
+                new RuntimeException(secret))) {
+            String line = UpdateDiagnosis.failure(t);
+            assertFalse(line, line.contains("example"));
+            assertFalse(line, line.contains("abc"));
+        }
+    }
+
+    @Test
+    public void statusesSayWhoIsAtFault() {
+        assertTrue(UpdateDiagnosis.status(302).contains("SIM without data"));
+        assertTrue(UpdateDiagnosis.status(401).contains("token"));
+        assertTrue(UpdateDiagnosis.status(403).contains("token"));
+        assertTrue(UpdateDiagnosis.status(404).contains("does not know"));
+        assertTrue(UpdateDiagnosis.status(502).contains("forge"));
+        assertTrue(UpdateDiagnosis.status(418).contains("HTTP 418"));
+    }
+
+    @Test
+    public void onlyA204IsTheInternetWorking() {
+        assertTrue(UpdateDiagnosis.internet(204).startsWith("the internet works"));
+        assertTrue(UpdateDiagnosis.internet(200).contains("in between"));
+        assertTrue(UpdateDiagnosis.internet(302).contains("SIM without data"));
+    }
+
+    @Test
+    public void aNetworkInOneLine() {
+        assertEquals("cellular, in use, offers internet, not confirmed by Android, roaming",
+                UpdateDiagnosis.network(Collections.singletonList("cellular"), true, false, true, true));
+        assertEquals("unknown type, no internet, confirmed by Android",
+                UpdateDiagnosis.network(Collections.emptyList(), false, true, false, false));
+    }
+}

app/src/unstable/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <!-- Unstable channel only. The stable build has no self-update path, so neither the install
      permission nor the session result receiver belongs in the main manifest. -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     android:sharedUserId="android.uid.system">
 
     <!-- Needed for the PackageInstaller session that replaced `pm install -r`. On this
@@ -11,6 +12,18 @@
     <uses-permission
         android:name="android.permission.WRITE_EXTERNAL_STORAGE"
         android:maxSdkVersion="28" />
+    <!-- Lists other apps' media sessions (MediaProbe, the Logs tab's music-sources check).
+         A platform permission: the system user has it; elsewhere the check says it cannot. -->
+    <uses-permission
+        android:name="android.permission.MEDIA_CONTENT_CONTROL"
+        tools:ignore="ProtectedPermissions" />
+
+    <!-- An update check writes down which networks Android sees (UpdateNetworkCheck). -->
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <!-- The Logs tab's sound check (SoundProbe): Android's audio analyser asks for both. The
+         system user holds them without a prompt; the analyser reports levels only, no sound. -->
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
 
     <application>
         <provider

app/src/unstable/java/com/evsuite/abrp/OtaInstallResultReceiver.java

@@ -16,10 +16,17 @@ import android.widget.Toast;
  * STATUS_PENDING_USER_ACTION is the case worth understanding: the platform is saying it will
  * install, but wants the driver to confirm. That happens when the app is not granted a silent
  * install, and the only correct response is to launch the confirmation activity it hands us.
+ *
+ * Any other failure — on the car the session is refused, "Not allowed to install non-system
+ * apps on internal storage", and that answer can come here rather than as an exception — opens
+ * Android's installer screen with the verified APK, as {@link OtaUpdater#install} does for an
+ * immediate refusal. Only a cancel by the driver ends there.
  */
 public final class OtaInstallResultReceiver extends BroadcastReceiver {
 
     static final String ACTION_INSTALL_RESULT = "com.stinnesbeck.nilsmg4.OTA_INSTALL_RESULT";
+    static final String EXTRA_APK = "com.stinnesbeck.nilsmg4.extra.APK";
+    static final String EXTRA_SESSION = "com.stinnesbeck.nilsmg4.extra.SESSION";
 
     private static final String TAG = "EVABRP.Update";
 
@@ -31,12 +38,16 @@ public final class OtaInstallResultReceiver extends BroadcastReceiver {
         Log.i(TAG, "OTA install result: status=" + status + " msg=" + message);
         UpdateLog.record(context, "Install result: status " + status
                 + (message != null ? ", " + message : ""));
+        int session = intent.getIntExtra(EXTRA_SESSION, -1);
+        if (session >= 0) OtaUpdater.noteAnswer(session);
+        String apkPath = intent.getStringExtra(EXTRA_APK);
 
         switch (status) {
             case PackageInstaller.STATUS_PENDING_USER_ACTION:
                 Intent confirm = intent.getParcelableExtra(Intent.EXTRA_INTENT);
                 if (confirm == null) {
-                    toast(context, context.getString(R.string.ota_install_failed, "no confirm intent"));
+                    UpdateLog.record(context, "No confirmation screen offered");
+                    openInstallerScreen(context, apkPath, "no confirm intent");
                     return;
                 }
                 confirm.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
@@ -44,23 +55,52 @@ public final class OtaInstallResultReceiver extends BroadcastReceiver {
                     context.startActivity(confirm);
                 } catch (Throwable t) {
                     Log.e(TAG, "OTA confirm UI failed: " + t.getMessage());
-                    toast(context, context.getString(R.string.ota_install_failed,
+                    UpdateLog.record(context, "Confirmation screen failed: " + t.getClass().getSimpleName());
-                            t.getClass().getSimpleName()));
+                    openInstallerScreen(context, apkPath, t.getClass().getSimpleName());
                 }
                 break;
             case PackageInstaller.STATUS_SUCCESS:
                 toast(context, context.getString(R.string.ota_install_success));
                 break;
+            case PackageInstaller.STATUS_FAILURE_ABORTED:
+                // The driver cancelled: nothing opens again.
+                toast(context, context.getString(R.string.ota_install_failed,
+                        message != null ? message : "cancelled"));
+                break;
             default:
                 // The status message is the package manager's own words — INSTALL_FAILED_*
-                // and friends. Surfaced verbatim, because guessing at it is what made the
+                // and friends — kept verbatim in the update log, because guessing at it is what
-                // previous failure unreadable.
+                // made an earlier failure unreadable. Then the installer screen, which the car
-                toast(context, context.getString(R.string.ota_install_failed,
+                // allows where it refuses the session.
-                        message != null ? message : "status " + status));
+                openInstallerScreen(context, apkPath, message != null ? message : "status " + status);
                 break;
         }
     }
 
+    /**
+     * Opens Android's installer screen for the APK at [apkPath] off the main thread (it is
+     * copied to Downloads first); a toast with [why] when there is none or it cannot open.
+     */
+    private void openInstallerScreen(Context context, String apkPath, String why) {
+        java.io.File apk = apkPath == null ? null : new java.io.File(apkPath);
+        if (apk == null || !apk.isFile()) {
+            toast(context, context.getString(R.string.ota_install_failed, why));
+            return;
+        }
+        PendingResult pending = goAsync();
+        Context app = context.getApplicationContext();
+        new Thread(() -> {
+            try {
+                if (!OtaUpdater.openInstallerScreen(app, apk)) {
+                    new android.os.Handler(android.os.Looper.getMainLooper()).post(() ->
+                            toast(app, app.getString(R.string.ota_install_failed, why)));
+                }
+            } finally {
+                pending.finish();
+            }
+        }, "ota-fallback").start();
+    }
+
     private static void toast(Context context, String text) {
         Toast.makeText(context.getApplicationContext(), text, Toast.LENGTH_LONG).show();
     }

app/src/unstable/java/com/evsuite/abrp/OtaUpdater.java

@@ -55,6 +55,9 @@ final class OtaUpdater {
     private static final String TAG = "OtaUpdater";
     private static final String CACHE_PREFIX = "NilsMG4-ota-";
 
+    /** Why the last download failed, for the update log. */
+    static volatile String downloadProblem = "unknown";
+
     /** The release list on the car server, for the server configured in the app. */
     static String releasesUrl(ServerConfig config) {
         return config.url + "/v1/app/releases";
@@ -366,6 +369,7 @@ final class OtaUpdater {
             connection.setRequestProperty("User-Agent", "NilsMG4-Android");
             if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                 Log.w(TAG, "Update download returned " + connection.getResponseCode());
+                downloadProblem = UpdateDiagnosis.status(connection.getResponseCode());
                 return null;
             }
             long total = connection.getContentLengthLong();
@@ -390,10 +394,14 @@ final class OtaUpdater {
                 out.getFD().sync();
             }
             ok = hex(digest.digest()).equalsIgnoreCase(expectedSha256);
-            if (!ok) Log.w(TAG, "Update APK does not match its SHA-256");
+            if (!ok) {
+                Log.w(TAG, "Update APK does not match its SHA-256");
+                downloadProblem = "it does not match its SHA-256";
+            }
             return ok ? target : null;
         } catch (Exception e) {
             Log.w(TAG, "Update download failed: " + e.getClass().getSimpleName());
+            downloadProblem = UpdateDiagnosis.failure(e);
             return null;
         } finally {
             if (connection != null) connection.disconnect();
@@ -464,21 +472,57 @@ final class OtaUpdater {
     static InstallResult install(Context context, File apk) {
         if (!archiveIsThisPackage(context, apk)) return InstallResult.UNREADABLE_ARCHIVE;
         try {
-            commitSession(context, apk);
+            int sessionId = commitSession(context, apk);
+            watchForAnswer(context, sessionId, apk);
             return InstallResult.SESSION_STARTED;
         } catch (Throwable t) {
             Log.w(TAG, "OTA session install failed; trying system install UI", t);
             UpdateLog.record(context, "Installer session failed: " + t);
+            return openInstallerScreen(context, apk) ? InstallResult.INSTALL_UI_STARTED : InstallResult.SESSION_FAILED;
+        }
+    }
+
+    /** The installer screen for [apk], as the fallback; false if even that could not open. */
+    static boolean openInstallerScreen(Context context, File apk) {
         try {
             launchInstallerActivity(context, apk);
             UpdateLog.record(context, "Opened the system installer instead");
-                return InstallResult.INSTALL_UI_STARTED;
+            return true;
         } catch (Throwable fallback) {
             Log.w(TAG, "OTA install UI failed", fallback);
             UpdateLog.record(context, "System installer failed too: " + fallback);
-                return InstallResult.SESSION_FAILED;
+            return false;
         }
     }
+
+    /** How long a committed session may stay silent before the installer screen is opened. */
+    private static final long ANSWER_WAIT_MS = 20_000L;
+    /** Sessions the platform has answered (any status), so the watch knows to stand down. */
+    private static final java.util.Set<Integer> answered =
+            java.util.Collections.synchronizedSet(new java.util.HashSet<>());
+
+    /** The platform said something about [sessionId]; called by {@link OtaInstallResultReceiver}. */
+    static void noteAnswer(int sessionId) {
+        answered.add(sessionId);
+    }
+
+    /**
+     * A committed session normally answers within a second or two: installed (the app
+     * restarts), refused, or "confirm on screen". If it says nothing at all, the update would
+     * end silently after its download, so the installer screen is opened instead.
+     */
+    private static void watchForAnswer(Context context, int sessionId, File apk) {
+        Context app = context.getApplicationContext();
+        new android.os.Handler(android.os.Looper.getMainLooper()).postDelayed(() -> {
+            if (answered.contains(sessionId)) return;
+            UpdateLog.record(app, "No answer from the installer after " + ANSWER_WAIT_MS / 1000 + " s");
+            try {
+                app.getPackageManager().getPackageInstaller().abandonSession(sessionId);
+            } catch (Throwable ignored) {
+                // already gone
+            }
+            new Thread(() -> openInstallerScreen(app, apk), "ota-fallback").start();
+        }, ANSWER_WAIT_MS);
     }
 
     /**
@@ -510,7 +554,8 @@ final class OtaUpdater {
         }
     }
 
-    private static void commitSession(Context context, File apk) throws Exception {
+    /** Commits [apk] to a new installer session and returns its id. */
+    private static int commitSession(Context context, File apk) throws Exception {
         PackageInstaller installer = context.getPackageManager().getPackageInstaller();
         PackageInstaller.SessionParams params = new PackageInstaller.SessionParams(
                 PackageInstaller.SessionParams.MODE_FULL_INSTALL);
@@ -533,7 +578,10 @@ final class OtaUpdater {
             }
             Intent callback = new Intent(context, OtaInstallResultReceiver.class)
                     .setAction(OtaInstallResultReceiver.ACTION_INSTALL_RESULT)
-                    .setPackage(context.getPackageName());
+                    .setPackage(context.getPackageName())
+                    // Where the verified APK is, for the installer screen if the session fails.
+                    .putExtra(OtaInstallResultReceiver.EXTRA_APK, apk.getAbsolutePath())
+                    .putExtra(OtaInstallResultReceiver.EXTRA_SESSION, sessionId);
             // MUTABLE: the platform fills in EXTRA_STATUS and, when it wants the driver to
             // confirm, EXTRA_INTENT. An immutable PendingIntent would arrive empty.
             PendingIntent pending = PendingIntent.getBroadcast(context, sessionId, callback,
@@ -543,6 +591,7 @@ final class OtaUpdater {
             session.commit(pending.getIntentSender());
             committed = true;
             Log.i(TAG, "OTA session " + sessionId + " committed (" + apk.length() + " bytes)");
+            return sessionId;
         } finally {
             // Abandon failed staging, but always close our local handle after a commit too.
             if (!committed) {

app/src/unstable/java/com/evsuite/abrp/UpdateHook.java

@@ -5,6 +5,11 @@ import android.util.Log;
 
 import java.io.File;
 import java.io.IOException;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
@@ -58,7 +63,8 @@ final class UpdateHook {
                                 "Update available: " + update.versionName,
                                 android.widget.Toast.LENGTH_LONG).show());
             } catch (Throwable t) {
-                Log.w(TAG, "Startup update check failed", t);
+                Log.w(TAG, "Startup update check failed: " + t.getClass().getSimpleName());
+                UpdateLog.record(app, "Check at start: " + UpdateDiagnosis.failure(t));
             }
         }, "ota-startup-check").start();
     }
@@ -78,24 +84,46 @@ final class UpdateHook {
             return;
         }
         new Thread(() -> {
+            long startedMs = System.currentTimeMillis();
+            List<String> steps = new ArrayList<>();
+            step(app, steps, "Check started, app " + BuildConfig.VERSION_NAME);
             String message;
             try {
+                for (String network : UpdateNetworkCheck.networks(app)) step(app, steps, network);
+                ServerConfig config = ServerConfig.get(app);
+                String host = config.isConfigured() ? OtaUpdater.allowedHost(config) : null;
+                if (host != null) step(app, steps, UpdateNetworkCheck.lookup(host));
                 message = runCheck(app, listener, main);
             } catch (Throwable t) {
-                Log.w(TAG, "Update check threw", t);
+                Log.w(TAG, "Update check threw: " + t.getClass().getSimpleName());
-                // The class only: a network error's text can carry the server's address.
+                message = "Update check failed: " + UpdateDiagnosis.failure(t);
-                message = "Update check failed (" + t.getClass().getSimpleName() + ")";
+                // Is it the server or the connection? The answer to "is my SIM out of data".
+                step(app, steps, UpdateNetworkCheck.internet());
             } finally {
                 checking.set(false);
             }
-            UpdateLog.record(app, "Check: " + message);
+            step(app, steps, "Check: " + message);
+            String waiting = LogOutbox.status(app);
+            if (waiting != null) step(app, steps, "Reports: " + waiting);
             if (listener != null) {
                 final String result = message;
                 main.post(() -> listener.onResult(result));
             }
+            // After the answer: without a connection this waits for the send to fail.
+            String name = "update-check-" + new SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+                    .format(new Date(startedMs)) + ".txt";
+            // Only the newest waits: repeated checks offline must not push out a recording.
+            LogOutbox.dropWaiting(app, "update-check-");
+            SignalRecorder.saveCopies(app, "update_check.txt", name, steps);
         }, "ota-check").start();
     }
 
+    /** One step of a check: on the Logs tab now, and in the report saved when it ends. */
+    private static void step(Context app, List<String> steps, String what) {
+        UpdateLog.record(app, what);
+        steps.add(what);
+    }
+
     /**
      * Installs the newest car build from the top folder of a USB stick (UsbUpdate), with the
      * same checks as the over-the-air update except the server. Background thread; [listener]
@@ -195,14 +223,14 @@ final class UpdateHook {
         try {
             expectedHash = OtaUpdater.fetchExpectedSha256(update, config);
         } catch (IOException e) {
-            Log.w(TAG, "OTA hash unavailable: " + e.getMessage());
+            Log.w(TAG, "OTA hash unavailable: " + e.getClass().getSimpleName());
-            return "Update refused: no SHA-256 verification";
+            return "Update refused, no SHA-256 verification: " + UpdateDiagnosis.failure(e);
         }
         File apk = OtaUpdater.download(update, expectedHash, config, percent -> {
             if (listener != null) main.post(() -> listener.onProgress(percent));
         });
         if (apk == null) return "Download or SHA-256 verification failed ("
-                + update.versionName + ")";
+                + update.versionName + "): " + OtaUpdater.downloadProblem;
 
         switch (OtaUpdater.install(app, apk)) {
             case SESSION_STARTED:

app/src/unstable/java/com/evsuite/abrp/UpdateNetworkCheck.java

@@ -0,0 +1,92 @@
+package com.evsuite.abrp;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.NetworkInfo;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.InetAddress;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * What an update check writes down about the connection before and after it fails: the networks
+ * Android sees, whether the server's name can be looked up, and whether the internet answers at
+ * all, which tells a SIM without data from a server that is down. Blocking: background thread.
+ * Never logs the server's address or anything about the car. — UNSTABLE BUILDS ONLY.
+ */
+final class UpdateNetworkCheck {
+
+    /** Android's own connectivity test, as Android itself uses it; no data about the car is sent. */
+    private static final String INTERNET_TEST = "https://www.gstatic.com/generate_204";
+    private static final int TIMEOUT_MS = 10_000;
+
+    private UpdateNetworkCheck() {}
+
+    /** One line per network, or one saying there is none. */
+    static List<String> networks(Context app) {
+        List<String> out = new ArrayList<>();
+        try {
+            ConnectivityManager cm = (ConnectivityManager) app.getSystemService(Context.CONNECTIVITY_SERVICE);
+            if (cm == null) {
+                out.add("Network: no connectivity service");
+                return out;
+            }
+            Network active = cm.getActiveNetwork();
+            if (active == null) out.add("Network: none in use");
+            for (Network network : cm.getAllNetworks()) {
+                NetworkCapabilities caps = cm.getNetworkCapabilities(network);
+                if (caps == null) continue;
+                NetworkInfo info = cm.getNetworkInfo(network);
+                out.add("Network: " + UpdateDiagnosis.network(transports(caps),
+                        caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET),
+                        caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED),
+                        network.equals(active), info != null && info.isRoaming()));
+            }
+        } catch (RuntimeException e) {
+            out.add("Network: unreadable (" + e.getClass().getSimpleName() + ")");
+        }
+        return out;
+    }
+
+    private static List<String> transports(NetworkCapabilities caps) {
+        List<String> out = new ArrayList<>();
+        if (caps.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) out.add("cellular");
+        if (caps.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) out.add("Wi-Fi");
+        if (caps.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET)) out.add("ethernet");
+        if (caps.hasTransport(NetworkCapabilities.TRANSPORT_BLUETOOTH)) out.add("Bluetooth");
+        if (caps.hasTransport(NetworkCapabilities.TRANSPORT_VPN)) out.add("VPN");
+        return out;
+    }
+
+    /** Whether the host's name resolves, without saying the name. */
+    static String lookup(String host) {
+        long started = System.currentTimeMillis();
+        try {
+            InetAddress.getByName(host);
+            return "Server's name: found in " + (System.currentTimeMillis() - started) + " ms";
+        } catch (IOException | RuntimeException e) {
+            return "Server's name: " + UpdateDiagnosis.failure(e);
+        }
+    }
+
+    /** Whether the world outside the car server answers. */
+    static String internet() {
+        HttpURLConnection conn = null;
+        try {
+            conn = (HttpURLConnection) new URL(INTERNET_TEST).openConnection();
+            conn.setInstanceFollowRedirects(false);
+            conn.setConnectTimeout(TIMEOUT_MS);
+            conn.setReadTimeout(TIMEOUT_MS);
+            return "Internet test: " + UpdateDiagnosis.internet(conn.getResponseCode());
+        } catch (IOException | RuntimeException e) {
+            return "Internet test: " + UpdateDiagnosis.failure(e);
+        } finally {
+            if (conn != null) conn.disconnect();
+        }
+    }
+}

flake.nix

@@ -161,10 +161,46 @@
               echo "Published $tag ($(basename "$apk") and .sha256) at $forge/$repo/releases/tag/$tag"
             '';
           };
+
+          # Fetches the files the car sent from its Logs tab (signal recordings) from the car
+          # server into logs/ (gitignored), those not there yet. Needs the server's LOGS_TOKEN,
+          # from $LOGS_TOKEN or ~/.config/nilsmg4/logs-token; sent in a header, never printed.
+          fetchLogs = pkgs.writeShellApplication {
+            name = "fetch-logs";
+            runtimeInputs = [ pkgs.curl pkgs.jq pkgs.coreutils pkgs.git ];
+            text = ''
+              server=''${SERVER_URL:-https://car.k8s.stinnesbeck.com}
+              token=''${LOGS_TOKEN:-}
+              if [ -z "$token" ] && [ -f "$HOME/.config/nilsmg4/logs-token" ]; then
+                token=$(tr -d '[:space:]' < "$HOME/.config/nilsmg4/logs-token")
+              fi
+              if [ -z "$token" ]; then
+                echo "fetch-logs: no token. Put the server's LOGS_TOKEN in ~/.config/nilsmg4/logs-token (or \$LOGS_TOKEN)." >&2
+                exit 1
+              fi
+              root=$(git rev-parse --show-toplevel)
+              mkdir -p "$root/logs"
+              auth=(-H "Authorization: Bearer $token")
+              fetched=0
+              while IFS= read -r name; do
+                # The server only stores such names; anything else is not a path to write to.
+                if ! [[ "$name" =~ ^[a-z0-9][a-z0-9-]{0,79}\.txt$ ]]; then
+                  echo "fetch-logs: skipping an unexpected name" >&2
+                  continue
+                fi
+                [ -f "$root/logs/$name" ] && continue
+                curl -sSf "''${auth[@]}" -o "$root/logs/$name.part" "$server/v1/logs/$name"
+                mv "$root/logs/$name.part" "$root/logs/$name"
+                echo "logs/$name"
+                fetched=$((fetched + 1))
+              done < <(curl -sSf "''${auth[@]}" "$server/v1/logs" | jq -r '.logs[].name')
+              echo "fetch-logs: $fetched new"
+            '';
+          };
         in
         {
           default = pkgs.mkShell {
-            packages = [ jdk android.androidsdk buildCar publishCar pkgs.go pkgs.gopls pkgs.govulncheck pkgs.influxdb2-server pkgs.influxdb2-cli ];
+            packages = [ jdk android.androidsdk buildCar publishCar fetchLogs pkgs.go pkgs.gopls pkgs.govulncheck pkgs.influxdb2-server pkgs.influxdb2-cli ];
 
             ANDROID_HOME = sdk;
             ANDROID_SDK_ROOT = sdk;
@@ -179,6 +215,7 @@
               echo "  ./gradlew assembleUnstableDebug   # build that can update itself (OTA)"
               echo "  build-car                         # unstable build signed for the car"
               echo "  publish-car                       # publish it for the in-app updater"
+              echo "  fetch-logs                        # the car's recordings from the server, into logs/"
             '';
           };
         });

k8s/README.md

@@ -7,7 +7,7 @@ is applied automatically. Apply them yourself.
 |---|---|
 | `namespace.yaml` | Namespace `mg4` |
 | `influxdb.yaml` | InfluxDB 2.7.12 StatefulSet (10Gi PVC, default storage class), cluster-internal Service, NetworkPolicy admitting only the server and Grafana |
-| `server.yaml` | Go server Deployment (1 replica, non-root, read-only root filesystem) and Service |
+| `server.yaml` | Go server Deployment (1 replica, non-root, read-only root filesystem), Service, and two 1Gi PVCs: the map tile cache and the logs the car sends |
 | `grafana.yaml` | Grafana 13.2.3 Deployment (1Gi PVC), Service; datasource and dashboards provisioned |
 | `grafana/` | The provisioned InfluxDB datasource and the MG4 dashboards (Live, Consumption, Charging) |
 | `ingress.yaml` | Traefik `IngressRoute`s for car.k8s.stinnesbeck.com and Grafana, TLS from Traefik's default certificate |
@@ -22,7 +22,8 @@ is applied automatically. Apply them yourself.
    covered by Traefik's default certificate.
 2. **Create the Secrets.** `cp k8s/secrets/secrets.example.yaml k8s/secrets/secrets.yaml` (gitignored), replace
    every `CHANGE-ME` there (`openssl rand -hex 32`): `influxdb-auth`, `mg4-server` (ingest token,
-   approval password for pairing, the forge token for app updates) and `grafana-admin`.
+   approval password for pairing, the forge token for app updates, the token that reads the
+   car's logs) and `grafana-admin`.
    Keep the template itself on placeholders only.
 3. **Registry access.** The `mg4-server` package on git.stinnesbeck.com is public, so no pull
    secret is needed. If you make it private, add an `imagePullSecrets` entry to `server.yaml`.
@@ -54,6 +55,14 @@ the forge that can only **read** the `nils/mg4` repository, put it there, apply
 restart the server. Without it, updates are off (the car's updater gets a 404). `FORGE_URL`
 and `FORGE_REPO` are set in `server.yaml`.
 
+## Logs from the car
+
+The car sends its signal recordings to the server (`server/README.md`, "Logs from the car"),
+which keeps them on the `mg4-server-logs` volume at `LOGS_DIR`. Reading them needs `LOGS_TOKEN`
+from the `mg4-server` Secret: `openssl rand -hex 32`, put it there (it must differ from
+`INGEST_TOKEN`), apply the Secret and restart the server. For `fetch-logs` on your machine, put
+the same value in `~/.config/nilsmg4/logs-token`. Without it the car still sends; nobody can read.
+
 ## Agent access
 
 [`agent-access/`](agent-access/README.md) creates a service account limited to the `mg4`

k8s/secrets/secrets.example.yaml

@@ -30,6 +30,9 @@ stringData:
   # relays the releases to the car; k8s/README.md, "App updates"). Leave it empty to switch
   # updates off.
   FORGE_TOKEN: CHANGE-ME-read-only-forge-token
+  # Reads the files the car sends from its Logs tab (GET /v1/logs). At least 24 characters and
+  # not the INGEST_TOKEN. Leave it empty to switch reading off; the car can still send.
+  LOGS_TOKEN: CHANGE-ME-openssl-rand-hex-32
 ---
 apiVersion: v1
 kind: Secret

k8s/server.yaml

@@ -1,5 +1,37 @@
 # The car server (Go). One replica on purpose: pending pairing requests and the wrong-password
 # counters are kept in memory.
+# The roads of the app's Grid map, fetched on demand, are kept on this small volume.
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: mg4-server-maps
+  namespace: mg4
+  labels:
+    app.kubernetes.io/name: mg4-server
+    app.kubernetes.io/part-of: mg4
+spec:
+  accessModes: ["ReadWriteOnce"]
+  # No storageClassName: the cluster's default class is used.
+  resources:
+    requests:
+      storage: 1Gi
+---
+# The files the car sends from its Logs tab (signal recordings), read with LOGS_TOKEN. Unlike
+# the map cache these are not fetched again, so they get a volume of their own.
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: mg4-server-logs
+  namespace: mg4
+  labels:
+    app.kubernetes.io/name: mg4-server
+    app.kubernetes.io/part-of: mg4
+spec:
+  accessModes: ["ReadWriteOnce"]
+  resources:
+    requests:
+      storage: 1Gi
+---
 apiVersion: apps/v1
 kind: Deployment
 metadata:
@@ -25,12 +57,13 @@ spec:
         runAsNonRoot: true
         runAsUser: 65532
         runAsGroup: 65532
+        fsGroup: 65532
         seccompProfile:
           type: RuntimeDefault
       containers:
         - name: server
-          # 2.6.2, pinned by digest so a re-pushed tag cannot change what runs.
+          # Pinned by digest so a re-pushed tag cannot change what runs (version in SPECS.md).
-          image: git.stinnesbeck.com/nils/mg4-server@sha256:e5da9452a9dbdfabe3340766cc51f18bb1418b2588ab534714550470abe1ce29
+          image: git.stinnesbeck.com/nils/mg4-server@sha256:c68837f0e53cfca150644987be535e04d5e999bd4c91064d40973db67235df48
           ports:
             - name: http
               containerPort: 8080
@@ -50,15 +83,22 @@ spec:
               value: https://git.stinnesbeck.com
             - name: FORGE_REPO
               value: nils/mg4
-            # The roads for the app's Grid map, from OpenStreetMap; "off" switches maps off.
+            # The roads for the app's Grid map: OpenStreetMap vector tiles, fetched only for the
-            - name: OVERPASS_URL
+            # tiles a car asks for and kept on the volume below; "off" switches maps off.
-              value: https://overpass-api.de/api/interpreter
+            - name: MAP_TILES_URL
+              value: https://tiles.openfreemap.org/planet
+            - name: MAP_CACHE_DIR
+              value: /var/cache/mg4-maps
+            # Files from the car's Logs tab, kept on the volume below (the newest 200, at most
+            # 180 days). Reading them needs LOGS_TOKEN from the Secret; empty switches reading off.
+            - name: LOGS_DIR
+              value: /var/lib/mg4-logs
             - name: INFLUX_TOKEN
               valueFrom:
                 secretKeyRef:
                   name: influxdb-auth
                   key: admin-token
-          # INGEST_TOKEN, APPROVAL_PASSWORD, FORGE_TOKEN.
+          # INGEST_TOKEN, APPROVAL_PASSWORD, FORGE_TOKEN, LOGS_TOKEN.
           envFrom:
             - secretRef:
                 name: mg4-server
@@ -84,6 +124,18 @@ spec:
             readOnlyRootFilesystem: true
             capabilities:
               drop: ["ALL"]
+          volumeMounts:
+            - name: maps
+              mountPath: /var/cache/mg4-maps
+            - name: logs
+              mountPath: /var/lib/mg4-logs
+      volumes:
+        - name: maps
+          persistentVolumeClaim:
+            claimName: mg4-server-maps
+        - name: logs
+          persistentVolumeClaim:
+            claimName: mg4-server-logs
 ---
 apiVersion: v1
 kind: Service

server/README.md

@@ -23,7 +23,10 @@ Environment only; the server refuses to start when a required value is missing.
 | `APPROVAL_PASSWORD` | optional, at least 12 characters; switches pairing on (see below) |
 | `PUBLIC_URL` | the address a phone uses, for the pairing QR code; derived from the request if empty |
 | `FORGE_URL`, `FORGE_REPO`, `FORGE_TOKEN` | optional; app updates (below). The token only needs to read the repository |
-| `OVERPASS_URL` | the Overpass API the map's roads come from; default `https://overpass-api.de/api/interpreter`, `off` switches maps off, otherwise https only |
+| `MAP_TILES_URL` | a TileJSON naming the vector tiles the map's roads come from; default OpenFreeMap's `https://tiles.openfreemap.org/planet`, `off` switches maps off, otherwise https only |
+| `MAP_CACHE_DIR` | where fetched map tiles are kept across restarts (the manifest mounts a volume there); empty keeps them in memory only |
+| `LOGS_DIR` | where the files the car sends from its Logs tab are kept (the manifest mounts a volume there); empty switches logs off |
+| `LOGS_TOKEN` | optional, at least 24 characters and not the `INGEST_TOKEN`; reads those files (below). Empty: the car can send, nobody can read |
 | `LISTEN_ADDR` | default `:8080` |
 
 ## Endpoints
@@ -42,6 +45,7 @@ with (403 otherwise); the shared token works for any.
 - `PUT /v1/charging-sessions/{sessionId}` — a finished charging session (AC or DC, as far as the car was awake) with its curve.
 - `GET /v1/consumption/history/{installationId}` — the car reads its own totals back.
 - `GET /v1/health` — `{"status":"ok"}`.
+- `PUT /v1/logs/{name}` — a file from the car's Logs tab (below).
 
 A malformed request is a 400 naming the field; a database failure is a 500 without detail.
 
@@ -60,18 +64,43 @@ download cut short`. The forge's address and token never appear in the log.
 
 ## Map roads
 
-`POST /v1/map/roads` `{z, x, y}`, with the car's token: the drivable roads (motorway to
+`POST /v1/map/roads` `{z, x, y}`, with the car's token: the drivable roads (motorway to minor
-residential) of one web-mercator tile at zoom 14, for the app's "Grid with map" style. The car
+streets) of one web-mercator tile at zoom 14, for the app's "Grid with map" style. The car names
-names the tile, not its position, and in the body, so it stays out of access logs. The answer is
+the tile, not its position, and in the body, so it stays out of access logs. The answer is
 `{z, x, y, extent: 4096, ways: [{c, p: [x, y, …]}]}`: per road its class (0 motorway and trunk,
-1 primary and secondary, 2 tertiary and unclassified, 3 residential and living streets) and its
+1 primary and secondary, 2 tertiary, 3 minor streets) and its points in tile units, simplified to
-points in tile units, simplified to about 1.5 m; gzipped when the car accepts it (20–30 KB a tile
+about 1.5 m; gzipped when the car accepts it (10–15 KB a tile in a city before that).
-in a city before that). The roads come from OpenStreetMap through `OVERPASS_URL`, one request at
+
-a time and at most one a second, with a User-Agent naming this service, and are kept in memory
+The roads are fetched **only for the tiles a car asks for**: the OpenStreetMap vector tile
-for 30 days (up to 3000 tiles); the car keeps its own copy too. 400 for anything but zoom 14 or
+(OpenMapTiles schema) of that square from the TileJSON at `MAP_TILES_URL` (by default
-a tile outside it, 503 when Overpass is busy or unreachable (not cached, the car tries again a
+OpenFreeMap: free, no key, no request limits; its template moves with each weekly build and is
-minute later), 404 when maps are off. The log says `map tile fetched` with the car's installation
+looked up every 6 hours), decoded by a small reader of our own (`mvt.go`, the `transportation`
-and the size, never the tile. Map data © OpenStreetMap contributors, ODbL.
+layer only). Each tile is fetched once and kept for 30 days in `MAP_CACHE_DIR` (and the last 300
+in memory); at most two fetches run at once. A request waits up to 6 s; a slower fetch goes on
+and is kept, and the car hears 503 with `Retry-After: 10` and gets the tile on its next try.
+400 for anything but zoom 14 or a tile outside it, 503 when the tile host fails (not cached),
+404 when maps are off. The log says `map tile fetched` with the size, never the tile.
+Map data © OpenStreetMap contributors (ODbL), tiles © OpenMapTiles, served by OpenFreeMap.
+
+## Logs from the car
+
+So a signal recording reaches the owner without a USB stick. The car sends each one when it ends
+(again later when it is offline) with its own token: `PUT /v1/logs/{name}`, plain UTF-8 text,
+gzipped (`Content-Encoding: gzip`) or not; at most 2 MB as sent and 8 MB unpacked. The name is
+the app's (`signal-recording-20261027-085240.txt`: lower-case letters, digits and dashes,
+`.txt`); the same name again replaces the file, so a retry is harmless. 204 when stored. The
+newest 200 files are kept, none older than 180 days.
+
+Reading takes `LOGS_TOKEN`, which can do nothing else, and the car's token cannot read:
+
+```sh
+curl -H "Authorization: Bearer $LOGS_TOKEN" https://car.k8s.stinnesbeck.com/v1/logs          # {logs: [{name, bytes, received}]}, newest first
+curl -H "Authorization: Bearer $LOGS_TOKEN" https://car.k8s.stinnesbeck.com/v1/logs/<name>   # the text
+```
+
+`fetch-logs` in the dev shell fetches the new ones into `logs/` (token from
+`~/.config/nilsmg4/logs-token`). 404 when reading is off. The log says `log received` with the
+name and size, never the contents.
 
 ## Settings from a phone
 

server/api.go

@@ -21,6 +21,7 @@ import (
 //	     /v1/settings/…, /settings                settings typed on a phone (handoff_http.go)
 //	GET  /v1/app/…                               app updates from the forge (releases.go)
 //	POST /v1/map/roads                           the roads of one map tile (maps.go)
+//	     /v1/logs/…                              files from the Logs tab, read with LOGS_TOKEN (logs.go)
 //
 // A car authenticates with the shared INGEST_TOKEN or with its own token from pairing
 // (pairing_http.go).
@@ -32,8 +33,10 @@ type API struct {
 	Handoff *Handoff
 	// Releases relays the app's releases from the private forge to the car (releases.go).
 	Releases *Releases
-	// Maps serves the roads for the Overview's map from OpenStreetMap (maps.go); nil is off.
+	// Maps serves the roads for the Overview's map from OpenStreetMap vector tiles (maps.go); nil is off.
 	Maps *Maps
+	// Logs keeps the files the car sends from its Logs tab (logs.go); nil is off.
+	Logs *Logs
 	// PublicURL is the server's address as a phone reaches it, for the pairing QR code;
 	// derived from the request when empty.
 	PublicURL string
@@ -54,6 +57,7 @@ func (a *API) Routes() http.Handler {
 	a.handoffRoutes(mux)
 	a.releaseRoutes(mux)
 	a.mapRoutes(mux)
+	a.logRoutes(mux)
 	return mux
 }
 

server/logs.go

@@ -0,0 +1,248 @@
+package main
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/subtle"
+	"errors"
+	"io"
+	"log/slog"
+	"net/http"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+	"unicode/utf8"
+)
+
+// Logs keeps the text files the car sends from its Logs tab (signal recordings) on a volume,
+// so they reach the owner without a USB stick. The car sends with its ingest token; reading
+// needs LOGS_TOKEN, a token of its own, so neither the car's token can read them nor this one
+// write anything.
+//
+//	PUT /v1/logs/{name}   one file from the car (ingest token); the same name again replaces it
+//	GET /v1/logs          the files, newest first (LOGS_TOKEN)
+//	GET /v1/logs/{name}   one file (LOGS_TOKEN)
+//
+// The newest maxLogFiles files younger than maxLogAge are kept. A file's contents never go to
+// the server log, only its name and size.
+type Logs struct {
+	Dir string
+	// ReadToken is LOGS_TOKEN; empty switches reading off (the car can still send).
+	ReadToken string
+
+	mu  sync.Mutex
+	now func() time.Time
+}
+
+const (
+	maxLogWireBytes = 2 << 20 // as sent, gzip or not
+	maxLogBytes     = 8 << 20 // as stored
+	maxLogFiles     = 200
+	maxLogAge       = 180 * 24 * time.Hour
+)
+
+// logName is what a file may be called: the app's own names, e.g. signal-recording-20261027-085240.txt.
+var logName = regexp.MustCompile(`^[a-z0-9][a-z0-9-]{0,79}\.txt$`)
+
+// NewLogs keeps the files in dir, which must exist.
+func NewLogs(dir, readToken string) *Logs {
+	return &Logs{Dir: dir, ReadToken: readToken, now: time.Now}
+}
+
+func (a *API) logRoutes(mux *http.ServeMux) {
+	if a.Logs == nil {
+		return
+	}
+	mux.HandleFunc("PUT /v1/logs/{name}", a.putLog)
+	mux.HandleFunc("GET /v1/logs", a.Logs.list)
+	mux.HandleFunc("GET /v1/logs/{name}", a.Logs.get)
+}
+
+func (a *API) putLog(w http.ResponseWriter, r *http.Request) {
+	if _, ok := a.authenticate(r); !ok {
+		writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+		return
+	}
+	name := r.PathValue("name")
+	if !logName.MatchString(name) {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be lower-case letters, digits and dashes, ending in .txt"})
+		return
+	}
+	text, status, msg := readLogBody(r)
+	if status != 0 {
+		writeJSON(w, status, map[string]string{"error": msg})
+		return
+	}
+	if err := a.Logs.save(name, text); err != nil {
+		slog.Error("log not stored", "name", name, "error", err)
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "internal server error"})
+		return
+	}
+	slog.Info("log received", "name", name, "bytes", len(text))
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// readLogBody is the request's text, un-gzipped when it says so; a status and message when it
+// is too large, not gzip after all, or not UTF-8 text.
+func readLogBody(r *http.Request) ([]byte, int, string) {
+	wire, err := io.ReadAll(io.LimitReader(r.Body, maxLogWireBytes+1))
+	if err != nil {
+		return nil, http.StatusBadRequest, "body could not be read"
+	}
+	if len(wire) > maxLogWireBytes {
+		return nil, http.StatusRequestEntityTooLarge, "body is too large"
+	}
+	text := wire
+	switch strings.ToLower(r.Header.Get("Content-Encoding")) {
+	case "", "identity":
+	case "gzip":
+		zr, err := gzip.NewReader(bytes.NewReader(wire))
+		if err != nil {
+			return nil, http.StatusBadRequest, "body is not gzip"
+		}
+		text, err = io.ReadAll(io.LimitReader(zr, maxLogBytes+1))
+		if err != nil {
+			return nil, http.StatusBadRequest, "body is not gzip"
+		}
+	default:
+		return nil, http.StatusUnsupportedMediaType, "only gzip or no encoding"
+	}
+	if len(text) > maxLogBytes {
+		return nil, http.StatusRequestEntityTooLarge, "body is too large"
+	}
+	if !utf8.Valid(text) {
+		return nil, http.StatusBadRequest, "body is not UTF-8 text"
+	}
+	return text, 0, ""
+}
+
+// save writes the file whole (a temporary file renamed into place), then prunes.
+func (l *Logs) save(name string, text []byte) error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	tmp, err := os.CreateTemp(l.Dir, ".incoming-*")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tmp.Name()) // gone after the rename; cleans up after a failure
+	if _, err := tmp.Write(text); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+	if err := os.Rename(tmp.Name(), filepath.Join(l.Dir, name)); err != nil {
+		return err
+	}
+	l.prune()
+	return nil
+}
+
+type logEntry struct {
+	Name     string    `json:"name"`
+	Bytes    int64     `json:"bytes"`
+	Received time.Time `json:"received"`
+}
+
+// entries are the stored files, newest first.
+func (l *Logs) entries() ([]logEntry, error) {
+	dir, err := os.ReadDir(l.Dir)
+	if err != nil {
+		return nil, err
+	}
+	var out []logEntry
+	for _, e := range dir {
+		if !e.Type().IsRegular() || !logName.MatchString(e.Name()) {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil {
+			continue
+		}
+		out = append(out, logEntry{Name: e.Name(), Bytes: info.Size(), Received: info.ModTime().UTC()})
+	}
+	sort.Slice(out, func(i, j int) bool {
+		if !out[i].Received.Equal(out[j].Received) {
+			return out[i].Received.After(out[j].Received)
+		}
+		return out[i].Name > out[j].Name
+	})
+	return out, nil
+}
+
+// prune removes all but the newest maxLogFiles and anything older than maxLogAge.
+func (l *Logs) prune() {
+	entries, err := l.entries()
+	if err != nil {
+		return
+	}
+	cutoff := l.now().Add(-maxLogAge)
+	for i, e := range entries {
+		if i >= maxLogFiles || e.Received.Before(cutoff) {
+			if err := os.Remove(filepath.Join(l.Dir, e.Name)); err != nil && !errors.Is(err, os.ErrNotExist) {
+				slog.Warn("old log not removed", "name", e.Name, "error", err)
+			}
+		}
+	}
+}
+
+// mayRead accepts LOGS_TOKEN only, compared in constant time; main refuses a short one.
+func (l *Logs) mayRead(w http.ResponseWriter, r *http.Request) bool {
+	if l.ReadToken == "" {
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": "reading logs is off (no LOGS_TOKEN)"})
+		return false
+	}
+	supplied, ok := strings.CutPrefix(r.Header.Get("Authorization"), "Bearer ")
+	if !ok || subtle.ConstantTimeCompare([]byte(supplied), []byte(l.ReadToken)) != 1 {
+		writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+		return false
+	}
+	return true
+}
+
+func (l *Logs) list(w http.ResponseWriter, r *http.Request) {
+	if !l.mayRead(w, r) {
+		return
+	}
+	l.mu.Lock()
+	entries, err := l.entries()
+	l.mu.Unlock()
+	if err != nil {
+		slog.Error("logs not listed", "error", err)
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "internal server error"})
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"logs": append([]logEntry{}, entries...)})
+}
+
+func (l *Logs) get(w http.ResponseWriter, r *http.Request) {
+	if !l.mayRead(w, r) {
+		return
+	}
+	name := r.PathValue("name")
+	if !logName.MatchString(name) {
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": "no such log"})
+		return
+	}
+	l.mu.Lock()
+	text, err := os.ReadFile(filepath.Join(l.Dir, name))
+	l.mu.Unlock()
+	if errors.Is(err, os.ErrNotExist) {
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": "no such log"})
+		return
+	}
+	if err != nil {
+		slog.Error("log not read", "name", name, "error", err)
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "internal server error"})
+		return
+	}
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write(text)
+}

server/logs_test.go

@@ -0,0 +1,212 @@
+package main
+
+import (
+	"bytes"
+	"compress/gzip"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+const testLogsToken = "logs-read-token-0123456789abcdef"
+
+func newLogsAPI(t *testing.T) (*API, string) {
+	t.Helper()
+	api, _ := newTestAPI()
+	dir := t.TempDir()
+	api.Logs = NewLogs(dir, testLogsToken)
+	return api, dir
+}
+
+func gzipped(t *testing.T, text string) []byte {
+	t.Helper()
+	var b bytes.Buffer
+	zw := gzip.NewWriter(&b)
+	if _, err := zw.Write([]byte(text)); err != nil {
+		t.Fatal(err)
+	}
+	if err := zw.Close(); err != nil {
+		t.Fatal(err)
+	}
+	return b.Bytes()
+}
+
+func putLog(t *testing.T, h http.Handler, name, token string, body []byte, encoding string) *httptest.ResponseRecorder {
+	t.Helper()
+	req := httptest.NewRequest("PUT", "/v1/logs/"+name, bytes.NewReader(body))
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("Content-Type", "text/plain; charset=utf-8")
+	if encoding != "" {
+		req.Header.Set("Content-Encoding", encoding)
+	}
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, req)
+	return rec
+}
+
+func TestTheCarSendsALogAndTheOwnerReadsIt(t *testing.T) {
+	api, _ := newLogsAPI(t)
+	h := api.Routes()
+	const name = "signal-recording-20261027-085240.txt"
+	text := "Signal recording, 37 captures\nlistening to 108 assistance properties\n"
+
+	if rec := putLog(t, h, name, testToken, gzipped(t, text), "gzip"); rec.Code != http.StatusNoContent {
+		t.Fatalf("put: %d %s", rec.Code, rec.Body)
+	}
+
+	rec := do(t, h, "GET", "/v1/logs", testLogsToken, "")
+	if rec.Code != 200 {
+		t.Fatalf("list: %d %s", rec.Code, rec.Body)
+	}
+	var list struct {
+		Logs []logEntry `json:"logs"`
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), &list); err != nil || len(list.Logs) != 1 || list.Logs[0].Name != name ||
+		list.Logs[0].Bytes != int64(len(text)) {
+		t.Fatalf("list: %v %s", err, rec.Body)
+	}
+
+	rec = do(t, h, "GET", "/v1/logs/"+name, testLogsToken, "")
+	if rec.Code != 200 || rec.Body.String() != text || !strings.HasPrefix(rec.Header().Get("Content-Type"), "text/plain") {
+		t.Fatalf("get: %d %q", rec.Code, rec.Body)
+	}
+
+	// Sent again (a retry), it replaces itself.
+	if rec := putLog(t, h, name, testToken, []byte("again\n"), ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("put again: %d", rec.Code)
+	}
+	if rec := do(t, h, "GET", "/v1/logs/"+name, testLogsToken, ""); rec.Body.String() != "again\n" {
+		t.Fatalf("replaced: %q", rec.Body)
+	}
+}
+
+func TestLogTokensDoNotCross(t *testing.T) {
+	api, _ := newLogsAPI(t)
+	h := api.Routes()
+	name := "signal-recording-1.txt"
+	if rec := putLog(t, h, name, testLogsToken, []byte("x"), ""); rec.Code != http.StatusUnauthorized {
+		t.Fatalf("the read token wrote: %d", rec.Code)
+	}
+	if rec := putLog(t, h, name, testToken, []byte("x"), ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("put: %d", rec.Code)
+	}
+	for _, path := range []string{"/v1/logs", "/v1/logs/" + name} {
+		for _, token := range []string{"", testToken, testLogsToken + "x"} {
+			if rec := do(t, h, "GET", path, token, ""); rec.Code != http.StatusUnauthorized {
+				t.Fatalf("GET %s with %q: %d", path, token, rec.Code)
+			}
+		}
+	}
+}
+
+func TestReadingIsOffWithoutALogsToken(t *testing.T) {
+	api, _ := newLogsAPI(t)
+	api.Logs.ReadToken = ""
+	h := api.Routes()
+	if rec := putLog(t, h, "a.txt", testToken, []byte("x"), ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("put: %d", rec.Code)
+	}
+	if rec := do(t, h, "GET", "/v1/logs", "", ""); rec.Code != http.StatusNotFound {
+		t.Fatalf("list: %d", rec.Code)
+	}
+}
+
+func TestBadLogsAreRefused(t *testing.T) {
+	api, dir := newLogsAPI(t)
+	h := api.Routes()
+	for _, c := range []struct {
+		name, encoding string
+		body           []byte
+		want           int
+	}{
+		{"..%2Fescape.txt", "", []byte("x"), http.StatusBadRequest},
+		{"Upper.txt", "", []byte("x"), http.StatusBadRequest},
+		{"no-suffix", "", []byte("x"), http.StatusBadRequest},
+		{".hidden.txt", "", []byte("x"), http.StatusBadRequest},
+		{"a.txt", "gzip", []byte("not gzip"), http.StatusBadRequest},
+		{"a.txt", "br", []byte("x"), http.StatusUnsupportedMediaType},
+		{"a.txt", "", []byte{0xff, 0xfe, 0x00}, http.StatusBadRequest},
+		{"a.txt", "", make([]byte, maxLogWireBytes+1), http.StatusRequestEntityTooLarge},
+		{"a.txt", "gzip", gzipped(t, strings.Repeat("a", maxLogBytes+1)), http.StatusRequestEntityTooLarge},
+	} {
+		if rec := putLog(t, h, c.name, testToken, c.body, c.encoding); rec.Code != c.want {
+			t.Errorf("%s %s: %d, want %d (%s)", c.name, c.encoding, rec.Code, c.want, rec.Body)
+		}
+	}
+	if files, _ := os.ReadDir(dir); len(files) != 0 {
+		t.Fatalf("stored: %v", files)
+	}
+	if rec := do(t, h, "GET", "/v1/logs/missing.txt", testLogsToken, ""); rec.Code != http.StatusNotFound {
+		t.Fatalf("missing: %d", rec.Code)
+	}
+}
+
+func TestOldAndSurplusLogsArePruned(t *testing.T) {
+	dir := t.TempDir()
+	l := NewLogs(dir, testLogsToken)
+	// The new file gets the real time as its own, so the others are placed before it.
+	now := time.Now()
+	old := filepath.Join(dir, "old.txt")
+	if err := os.WriteFile(old, []byte("x"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chtimes(old, now.Add(-maxLogAge-time.Hour), now.Add(-maxLogAge-time.Hour)); err != nil {
+		t.Fatal(err)
+	}
+	for i := 0; i < maxLogFiles+5; i++ {
+		p := filepath.Join(dir, fmt.Sprintf("f-%03d.txt", i))
+		if err := os.WriteFile(p, []byte("x"), 0o600); err != nil {
+			t.Fatal(err)
+		}
+		at := now.Add(-time.Duration(maxLogFiles+5-i) * time.Minute)
+		if err := os.Chtimes(p, at, at); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := l.save("new.txt", []byte("y")); err != nil {
+		t.Fatal(err)
+	}
+	entries, _ := l.entries()
+	if len(entries) != maxLogFiles || entries[0].Name != "new.txt" {
+		t.Fatalf("%d kept, first %s", len(entries), entries[0].Name)
+	}
+	if _, err := os.Stat(old); !os.IsNotExist(err) {
+		t.Fatal("the old one is still there")
+	}
+	if _, err := os.Stat(filepath.Join(dir, "f-000.txt")); !os.IsNotExist(err) {
+		t.Fatal("the oldest surplus one is still there")
+	}
+}
+
+func TestLogsConfig(t *testing.T) {
+	base := map[string]string{"INFLUX_URL": "http://i", "INFLUX_TOKEN": "t", "INFLUX_ORG": "o", "INGEST_TOKEN": testToken}
+	env := func(extra map[string]string) func(string) string {
+		return func(k string) string {
+			if v, ok := extra[k]; ok {
+				return v
+			}
+			return base[k]
+		}
+	}
+	for _, c := range []struct {
+		extra map[string]string
+		ok    bool
+	}{
+		{map[string]string{}, true},
+		{map[string]string{"LOGS_DIR": "/l"}, true},
+		{map[string]string{"LOGS_DIR": "/l", "LOGS_TOKEN": testLogsToken}, true},
+		{map[string]string{"LOGS_TOKEN": testLogsToken}, false},
+		{map[string]string{"LOGS_DIR": "/l", "LOGS_TOKEN": "short"}, false},
+		{map[string]string{"LOGS_DIR": "/l", "LOGS_TOKEN": testToken}, false},
+	} {
+		if _, err := loadConfig(env(c.extra)); (err == nil) != c.ok {
+			t.Errorf("%v: %v", c.extra, err)
+		}
+	}
+}

server/main.go

@@ -34,7 +34,10 @@ type config struct {
 	forgeURL     string
 	forgeRepo    string
 	forgeToken   string
-	overpassURL  string
+	mapTilesURL  string
+	mapCacheDir  string
+	logsDir      string
+	logsToken    string
 }
 
 // loadConfig reads the environment and fails closed: a missing InfluxDB setting or a
@@ -52,7 +55,10 @@ func loadConfig(getenv func(string) string) (config, error) {
 		forgeURL:     getenv("FORGE_URL"),
 		forgeRepo:    getenv("FORGE_REPO"),
 		forgeToken:   getenv("FORGE_TOKEN"),
-		overpassURL:  getenv("OVERPASS_URL"),
+		mapTilesURL:  getenv("MAP_TILES_URL"),
+		mapCacheDir:  getenv("MAP_CACHE_DIR"),
+		logsDir:      getenv("LOGS_DIR"),
+		logsToken:    getenv("LOGS_TOKEN"),
 	}
 	if c.listenAddr == "" {
 		c.listenAddr = ":8080"
@@ -75,18 +81,29 @@ func loadConfig(getenv func(string) string) (config, error) {
 	if c.forgeURL != "" && !strings.HasPrefix(c.forgeURL, "https://") {
 		return config{}, errors.New("FORGE_URL must be an https URL")
 	}
-	// The map's roads come from an Overpass API: the public one unless another is named, none
+	// The map's roads come from vector tiles named by a TileJSON: OpenFreeMap unless another is
-	// with "off". Only https, like the forge.
+	// named, none with "off". Only https, like the forge.
-	switch c.overpassURL {
+	switch c.mapTilesURL {
 	case "":
-		c.overpassURL = DefaultOverpassURL
+		c.mapTilesURL = DefaultMapTilesURL
 	case "off":
-		c.overpassURL = ""
+		c.mapTilesURL = ""
 	default:
-		if !strings.HasPrefix(c.overpassURL, "https://") {
+		if !strings.HasPrefix(c.mapTilesURL, "https://") {
-			return config{}, errors.New("OVERPASS_URL must be an https URL or \"off\"")
+			return config{}, errors.New("MAP_TILES_URL must be an https URL or \"off\"")
 		}
 	}
+	// Logs from the car are optional (LOGS_DIR); reading them needs a token of their own, as
+	// long as the ingest token, and never the ingest token itself.
+	if c.logsToken != "" && c.logsDir == "" {
+		return config{}, errors.New("LOGS_TOKEN is set but LOGS_DIR is not")
+	}
+	if c.logsToken != "" && len(c.logsToken) < minIngestTokenLength {
+		return config{}, fmt.Errorf("LOGS_TOKEN must be at least %d characters", minIngestTokenLength)
+	}
+	if c.logsToken != "" && c.logsToken == c.ingestToken {
+		return config{}, errors.New("LOGS_TOKEN must differ from INGEST_TOKEN")
+	}
 	if c.approvalPass != "" && len(c.approvalPass) < minApprovalPasswordLength {
 		return config{}, fmt.Errorf("APPROVAL_PASSWORD must be at least %d characters", minApprovalPasswordLength)
 	}
@@ -116,8 +133,21 @@ func main() {
 	releases := &Releases{ForgeURL: cfg.forgeURL, Repo: cfg.forgeRepo, Token: cfg.forgeToken}
 	api := &API{Store: store, IngestToken: cfg.ingestToken, Pairing: pairing, Handoff: NewHandoff(),
 		Releases: releases, PublicURL: cfg.publicURL}
-	if cfg.overpassURL != "" {
+	if cfg.mapTilesURL != "" {
-		api.Maps = NewMaps(cfg.overpassURL, mapUserAgent)
+		if cfg.mapCacheDir != "" {
+			if err := os.MkdirAll(cfg.mapCacheDir, 0o700); err != nil {
+				slog.Error("map cache directory not usable", "error", err)
+				os.Exit(1)
+			}
+		}
+		api.Maps = NewMaps(cfg.mapTilesURL, cfg.mapCacheDir, mapUserAgent)
+	}
+	if cfg.logsDir != "" {
+		if err := os.MkdirAll(cfg.logsDir, 0o700); err != nil {
+			slog.Error("logs directory not usable", "error", err)
+			os.Exit(1)
+		}
+		api.Logs = NewLogs(cfg.logsDir, cfg.logsToken)
 	}
 
 	srv := &http.Server{
@@ -134,7 +164,7 @@ func main() {
 	go func() {
 		slog.Info("listening", "addr", cfg.listenAddr, "bucket", cfg.influxBucket,
 			"pairing", pairing.Enabled(), "pairedDevices", len(devices), "appUpdates", releases.enabled(),
-			"maps", api.Maps != nil)
+			"maps", api.Maps != nil, "logs", api.Logs != nil, "logsReadable", api.Logs != nil && cfg.logsToken != "")
 		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
 			slog.Error("server failed", "error", err)
 			os.Exit(1)

server/maps.go

@@ -12,53 +12,69 @@ import (
 	"math"
 	"net/http"
 	"net/url"
+	"os"
+	"path/filepath"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
 )
 
-// Maps serves the roads around the car for the Overview's map (the "Grid with map" style),
+// Maps serves the roads around the car for the Overview's map (the "Grid with map" style). It
-// taken from OpenStreetMap through an Overpass API and cached here, so the car only ever
+// fetches only the tiles a car asks for, as OpenStreetMap vector tiles (OpenMapTiles schema,
-// talks to this server and asks Overpass nothing itself.
+// by default from OpenFreeMap), keeps their roads and stores them, so each tile is fetched
+// once and the car only ever talks to this server.
 //
 //	POST /v1/map/roads   {"z":14,"x":…,"y":…}
 //	                     → {"z","x","y","extent":4096,"ways":[{"c":class,"p":[x,y,x,y,…]}]}
 //
 // The car names a web-mercator tile at zoom 14 (about 1.5 km across in central Europe), not
-// its position, and the request goes in the body so the tile stays out of access logs. Points
+// its position, and in the body so the tile stays out of access logs. Points are tile-local
-// are tile-local in 0..4096 (they may lie a little outside: a road is kept up to the first
+// in 0..4096 (a little beyond at the edges), simplified to about 1.5 m. Classes: 0 motorway and
-// point beyond the edge), simplified to about 1.5 m. Classes: 0 motorway and trunk, 1 primary
+// trunk, 1 primary and secondary, 2 tertiary, 3 minor streets (residential, unclassified,
-// and secondary, 2 tertiary and unclassified, 3 residential and living streets.
+// living streets).
 //
-// Overpass is asked one tile at a time, at most once a second; a tile is kept for 30 days,
+// A fetch runs to its end even when the car stops waiting (the car gives up after a few
-// up to mapCacheTiles of them. The tile's coordinates never appear in the log.
+// seconds), so its next try finds the tile. Tiles are kept in memory (the last mapMemoryTiles)
+// and, with a cache directory, on disk for mapCacheAge. The tile's coordinates never appear
+// in the log.
 type Maps struct {
-	OverpassURL string
+	// TileJSONURL names the vector tiles: a TileJSON document whose first "tiles" template is
+	// used (OpenFreeMap moves its template with every weekly build).
+	TileJSONURL string
+	// CacheDir keeps fetched tiles across restarts; empty keeps them in memory only.
+	CacheDir  string
 	UserAgent string
 	Client    *http.Client
 
 	mu       sync.Mutex
-	tiles map[mapTile]mapEntry
+	memory   map[mapTile]mapEntry
-
+	inflight map[mapTile]*mapFlight
-	fetchMu   sync.Mutex // one Overpass request at a time
+	template string
-	lastFetch time.Time
+	tmplAt   time.Time
-	gap       time.Duration
+	// slots limits fetches running at once.
+	slots chan struct{}
 }
 
 const (
 	mapZoom        = 14
 	mapExtent      = 4096
-	mapCacheTiles    = 3000
+	mapMemoryTiles = 300
 	mapCacheAge    = 30 * 24 * time.Hour
-	maxOverpassBytes = 32 << 20
+	maxTileBytes   = 8 << 20
+	mapFetchTime   = 60 * time.Second
+	templateAge    = 6 * time.Hour
 	// The simplification tolerance in tile units (about 0.37 m each at 52° N).
 	mapTolerance = 4.0
-	// DefaultOverpassURL is the public instance of the Overpass API.
+	// DefaultMapTilesURL is OpenFreeMap's TileJSON: free OpenStreetMap vector tiles, no key.
-	DefaultOverpassURL = "https://overpass-api.de/api/interpreter"
+	DefaultMapTilesURL = "https://tiles.openfreemap.org/planet"
-	// mapUserAgent names this service to Overpass, as its usage policy asks.
+	// mapUserAgent names this service to the tile host.
-	mapUserAgent = "nils-mg4-server/2.7 (private car dashboard; roads for an in-car map)"
+	mapUserAgent = "nils-mg4-server/2.8 (private car dashboard; roads for an in-car map)"
 )
 
+// mapWait is how long a request waits for a fetch: less than the car's own 8 s.
+var mapWait = 6 * time.Second
+
 type mapTile struct{ Z, X, Y int }
 
 type mapEntry struct {
@@ -66,12 +82,19 @@ type mapEntry struct {
 	at   time.Time
 }
 
-// roadClasses maps OSM's highway values to the four classes the car draws.
+type mapFlight struct {
+	done chan struct{}
+	body []byte
+	err  error
+}
+
+// roadClasses maps the OpenMapTiles transportation classes to the four the car draws; the
+// rest (service, track, path, rail, ferry…) are left out.
 var roadClasses = map[string]int{
-	"motorway": 0, "motorway_link": 0, "trunk": 0, "trunk_link": 0,
+	"motorway": 0, "trunk": 0,
-	"primary": 1, "primary_link": 1, "secondary": 1, "secondary_link": 1,
+	"primary": 1, "secondary": 1,
-	"tertiary": 2, "tertiary_link": 2, "unclassified": 2,
+	"tertiary": 2,
-	"residential": 3, "living_street": 3,
+	"minor":    3,
 }
 
 type roadTile struct {
@@ -87,92 +110,227 @@ type road struct {
 	P []int `json:"p"`
 }
 
-func NewMaps(overpassURL, userAgent string) *Maps {
+func NewMaps(tileJSONURL, cacheDir, userAgent string) *Maps {
-	return &Maps{OverpassURL: overpassURL, UserAgent: userAgent, gap: time.Second}
+	return &Maps{TileJSONURL: tileJSONURL, CacheDir: cacheDir, UserAgent: userAgent}
 }
 
 func (m *Maps) client() *http.Client {
 	if m.Client != nil {
 		return m.Client
 	}
-	return &http.Client{Timeout: 60 * time.Second}
+	return &http.Client{Timeout: mapFetchTime}
 }
 
-// tileBounds is the tile's south, west, north and east edge in degrees.
+// Tile returns the tile's roads as JSON and whether it came from a cache. Waiting ends with
-func tileBounds(t mapTile) (s, w, n, e float64) {
+// ctx; the fetch itself goes on and is kept.
-	scale := math.Exp2(float64(t.Z))
+func (m *Maps) Tile(ctx context.Context, t mapTile) ([]byte, bool, error) {
-	lon := func(x float64) float64 { return x/scale*360 - 180 }
+	if body, ok := m.cached(t); ok {
-	lat := func(y float64) float64 { return math.Atan(math.Sinh(math.Pi*(1-2*y/scale))) * 180 / math.Pi }
+		return body, true, nil
-	return lat(float64(t.Y + 1)), lon(float64(t.X)), lat(float64(t.Y)), lon(float64(t.X + 1))
+	}
+	m.mu.Lock()
+	if m.inflight == nil {
+		m.inflight = map[mapTile]*mapFlight{}
+		m.slots = make(chan struct{}, 2)
+	}
+	f, running := m.inflight[t]
+	if !running {
+		f = &mapFlight{done: make(chan struct{})}
+		m.inflight[t] = f
+		go m.run(t, f)
+	}
+	m.mu.Unlock()
+	select {
+	case <-f.done:
+		return f.body, false, f.err
+	case <-ctx.Done():
+		return nil, false, errors.New("still fetching")
+	}
 }
 
-// tilePoint is a position in the tile's own units: 0..extent across, y downwards.
+func (m *Maps) run(t mapTile, f *mapFlight) {
-func tilePoint(t mapTile, lat, lon float64) (int, int) {
+	defer func() {
-	scale := math.Exp2(float64(t.Z)) * mapExtent
+		m.mu.Lock()
-	x := (lon + 180) / 360 * scale
+		delete(m.inflight, t)
-	r := lat * math.Pi / 180
+		m.mu.Unlock()
-	y := (1 - math.Log(math.Tan(r)+1/math.Cos(r))/math.Pi) / 2 * scale
+		close(f.done)
-	return int(math.Round(x - float64(t.X)*mapExtent)), int(math.Round(y - float64(t.Y)*mapExtent))
+	}()
+	m.slots <- struct{}{}
+	defer func() { <-m.slots }()
+	ctx, cancel := context.WithTimeout(context.Background(), mapFetchTime)
+	defer cancel()
+	raw, err := m.fetch(ctx, t)
+	if err == nil {
+		f.body, err = buildTile(t, raw)
+	}
+	if err != nil {
+		f.err = err
+		return
+	}
+	m.store(t, f.body)
+	slog.Info("map tile fetched", "ways", strings.Count(string(f.body), `"c":`), "bytes", len(f.body))
 }
 
-// overpassQuery asks for the drivable roads in the tile, with a small margin so that roads
+func (m *Maps) cachePath(t mapTile) string {
-// crossing its edge reach a point beyond it.
+	return filepath.Join(m.CacheDir, fmt.Sprintf("%d_%d_%d.json", t.Z, t.X, t.Y))
-func overpassQuery(t mapTile) string {
-	s, w, n, e := tileBounds(t)
-	dy, dx := (n-s)*0.03, (e-w)*0.03
-	box := fmt.Sprintf("%.6f,%.6f,%.6f,%.6f", s-dy, w-dx, n+dy, e+dx)
-	return "[out:json][timeout:50];way[\"highway\"~\"^(motorway|motorway_link|trunk|trunk_link|primary|primary_link|" +
-		"secondary|secondary_link|tertiary|tertiary_link|unclassified|residential|living_street)$\"](" + box +
-		");out geom(" + box + ");"
 }
 
-type overpassResult struct {
+func (m *Maps) cached(t mapTile) ([]byte, bool) {
-	Elements []struct {
+	m.mu.Lock()
-		Type     string            `json:"type"`
+	e, ok := m.memory[t]
-		Tags     map[string]string `json:"tags"`
+	m.mu.Unlock()
-		Geometry []*struct {
+	if ok && time.Since(e.at) <= mapCacheAge {
-			Lat float64 `json:"lat"`
+		return e.body, true
-			Lon float64 `json:"lon"`
+	}
-		} `json:"geometry"`
+	if m.CacheDir == "" {
-	} `json:"elements"`
+		return nil, false
+	}
+	info, err := os.Stat(m.cachePath(t))
+	if err != nil || time.Since(info.ModTime()) > mapCacheAge {
+		return nil, false
+	}
+	body, err := os.ReadFile(m.cachePath(t))
+	if err != nil || !json.Valid(body) {
+		return nil, false
+	}
+	m.remember(t, body, info.ModTime())
+	return body, true
 }
 
-// buildTile turns Overpass's answer into the tile the car reads. A missing point (outside
+func (m *Maps) store(t mapTile, body []byte) {
-// the clipped geometry) splits a road in two.
+	m.remember(t, body, time.Now())
+	if m.CacheDir == "" {
+		return
+	}
+	tmp := m.cachePath(t) + ".tmp"
+	if err := os.WriteFile(tmp, body, 0o600); err != nil {
+		slog.Warn("map tile not stored", "error", err)
+		return
+	}
+	if err := os.Rename(tmp, m.cachePath(t)); err != nil {
+		slog.Warn("map tile not stored", "error", err)
+	}
+}
+
+// remember keeps the tile in memory, dropping the oldest when full.
+func (m *Maps) remember(t mapTile, body []byte, at time.Time) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.memory == nil {
+		m.memory = map[mapTile]mapEntry{}
+	}
+	if _, ok := m.memory[t]; !ok && len(m.memory) >= mapMemoryTiles {
+		var oldest mapTile
+		var first time.Time
+		for k, e := range m.memory {
+			if first.IsZero() || e.at.Before(first) {
+				oldest, first = k, e.at
+			}
+		}
+		delete(m.memory, oldest)
+	}
+	m.memory[t] = mapEntry{body: body, at: at}
+}
+
+func (m *Maps) get(ctx context.Context, u string, limit int64) ([]byte, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("User-Agent", m.UserAgent)
+	resp, err := m.client().Do(req)
+	if err != nil {
+		// The URL holds the tile: name the failure, not the request.
+		if errors.Is(err, context.DeadlineExceeded) || errors.Is(ctx.Err(), context.DeadlineExceeded) {
+			return nil, errors.New("tile host timed out")
+		}
+		return nil, errors.New("tile host could not be reached")
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, 1<<16))
+		return nil, fmt.Errorf("tile host answered %d", resp.StatusCode)
+	}
+	body, err := io.ReadAll(io.LimitReader(resp.Body, limit+1))
+	if err != nil {
+		return nil, errors.New("tile host answer could not be read")
+	}
+	if int64(len(body)) > limit {
+		return nil, errors.New("tile host answer is too large")
+	}
+	return body, nil
+}
+
+// tileTemplate is the current {z}/{x}/{y} URL from the TileJSON, looked up every few hours.
+func (m *Maps) tileTemplate(ctx context.Context) (string, error) {
+	m.mu.Lock()
+	tmpl, at := m.template, m.tmplAt
+	m.mu.Unlock()
+	if tmpl != "" && time.Since(at) < templateAge {
+		return tmpl, nil
+	}
+	body, err := m.get(ctx, m.TileJSONURL, 1<<20)
+	if err != nil {
+		return "", err
+	}
+	var doc struct {
+		Tiles []string `json:"tiles"`
+	}
+	if err := json.Unmarshal(body, &doc); err != nil || len(doc.Tiles) == 0 {
+		return "", errors.New("tile index has no tiles")
+	}
+	tmpl = doc.Tiles[0]
+	u, err := url.Parse(strings.NewReplacer("{z}", "0", "{x}", "0", "{y}", "0").Replace(tmpl))
+	if err != nil || u.Scheme != "https" || u.Host == "" ||
+		!strings.Contains(tmpl, "{z}") || !strings.Contains(tmpl, "{x}") || !strings.Contains(tmpl, "{y}") {
+		return "", errors.New("tile index names no usable https template")
+	}
+	m.mu.Lock()
+	m.template, m.tmplAt = tmpl, time.Now()
+	m.mu.Unlock()
+	return tmpl, nil
+}
+
+func (m *Maps) fetch(ctx context.Context, t mapTile) ([]byte, error) {
+	tmpl, err := m.tileTemplate(ctx)
+	if err != nil {
+		return nil, err
+	}
+	u := strings.NewReplacer("{z}", strconv.Itoa(t.Z), "{x}", strconv.Itoa(t.X), "{y}", strconv.Itoa(t.Y)).Replace(tmpl)
+	raw, err := m.get(ctx, u, maxTileBytes)
+	if err != nil {
+		return nil, err
+	}
+	// Some hosts send the tile gzipped whatever the request said.
+	if len(raw) > 2 && raw[0] == 0x1f && raw[1] == 0x8b {
+		zr, err := gzip.NewReader(bytes.NewReader(raw))
+		if err != nil {
+			return nil, errors.New("tile is not readable")
+		}
+		raw, err = io.ReadAll(io.LimitReader(zr, maxTileBytes+1))
+		if err != nil || len(raw) > maxTileBytes {
+			return nil, errors.New("tile is not readable")
+		}
+	}
+	return raw, nil
+}
+
+// buildTile keeps the roads of the vector tile's transportation layer, in the car's format.
 func buildTile(t mapTile, raw []byte) ([]byte, error) {
-	var res overpassResult
+	lines, err := decodeRoads(raw)
-	if err := json.Unmarshal(raw, &res); err != nil {
+	if err != nil {
-		return nil, fmt.Errorf("overpass answer: %w", err)
+		return nil, err
 	}
 	out := roadTile{Z: t.Z, X: t.X, Y: t.Y, Extent: mapExtent, Ways: []road{}}
-	for _, el := range res.Elements {
+	for _, l := range lines {
-		class, ok := roadClasses[el.Tags["highway"]]
+		pts := simplify(l.points, mapTolerance)
-		if el.Type != "way" || !ok {
+		if len(pts) < 2 {
 			continue
 		}
-		var run [][2]int
-		flush := func() {
-			if pts := simplify(run, mapTolerance); len(pts) >= 2 {
 		flat := make([]int, 0, len(pts)*2)
 		for _, p := range pts {
 			flat = append(flat, p[0], p[1])
 		}
-				out.Ways = append(out.Ways, road{C: class, P: flat})
+		out.Ways = append(out.Ways, road{C: l.class, P: flat})
-			}
-			run = nil
-		}
-		for _, g := range el.Geometry {
-			if g == nil {
-				flush()
-				continue
-			}
-			x, y := tilePoint(t, g.Lat, g.Lon)
-			if n := len(run); n > 0 && run[n-1] == [2]int{x, y} {
-				continue
-			}
-			run = append(run, [2]int{x, y})
-		}
-		flush()
 	}
 	return json.Marshal(out)
 }
@@ -216,100 +374,11 @@ func segmentDistance(p, a, b [2]int) float64 {
 	if dx == 0 && dy == 0 {
 		return math.Hypot(px-ax, py-ay)
 	}
-	u := math.Max(0, math.Min(1, ((px-ax)*dx+(py-ay)*dy)/(dx*dx+dy*dy)))
+	u := ((px-ax)*dx + (py-ay)*dy) / (dx*dx + dy*dy)
+	u = max(0, min(1, u))
 	return math.Hypot(px-ax-u*dx, py-ay-u*dy)
 }
 
-// Tile returns the tile's roads as JSON, from the cache or from Overpass, and whether it
-// came from the cache.
-func (m *Maps) Tile(ctx context.Context, t mapTile) ([]byte, bool, error) {
-	if body, ok := m.cached(t); ok {
-		return body, true, nil
-	}
-	m.fetchMu.Lock()
-	defer m.fetchMu.Unlock()
-	// Another request may have fetched it while this one waited.
-	if body, ok := m.cached(t); ok {
-		return body, true, nil
-	}
-	if wait := m.gap - time.Since(m.lastFetch); wait > 0 {
-		select {
-		case <-time.After(wait):
-		case <-ctx.Done():
-			return nil, false, ctx.Err()
-		}
-	}
-	m.lastFetch = time.Now()
-	raw, err := m.fetch(ctx, t)
-	if err != nil {
-		return nil, false, err
-	}
-	body, err := buildTile(t, raw)
-	if err != nil {
-		return nil, false, err
-	}
-	m.store(t, body)
-	return body, false, nil
-}
-
-func (m *Maps) cached(t mapTile) ([]byte, bool) {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	e, ok := m.tiles[t]
-	if !ok || time.Since(e.at) > mapCacheAge {
-		return nil, false
-	}
-	return e.body, true
-}
-
-// store keeps the tile, dropping the oldest when the cache is full.
-func (m *Maps) store(t mapTile, body []byte) {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	if m.tiles == nil {
-		m.tiles = map[mapTile]mapEntry{}
-	}
-	if len(m.tiles) >= mapCacheTiles {
-		var oldest mapTile
-		var at time.Time
-		for k, e := range m.tiles {
-			if at.IsZero() || e.at.Before(at) {
-				oldest, at = k, e.at
-			}
-		}
-		delete(m.tiles, oldest)
-	}
-	m.tiles[t] = mapEntry{body: body, at: time.Now()}
-}
-
-// fetch asks Overpass. The query goes in the body, so its errors never carry the tile.
-func (m *Maps) fetch(ctx context.Context, t mapTile) ([]byte, error) {
-	form := url.Values{"data": {overpassQuery(t)}}.Encode()
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, m.OverpassURL, strings.NewReader(form))
-	if err != nil {
-		return nil, err
-	}
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
-	req.Header.Set("User-Agent", m.UserAgent)
-	resp, err := m.client().Do(req)
-	if err != nil {
-		return nil, errors.New("overpass could not be reached")
-	}
-	defer resp.Body.Close()
-	if resp.StatusCode != http.StatusOK {
-		_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, 1<<16))
-		return nil, fmt.Errorf("overpass answered %d", resp.StatusCode)
-	}
-	raw, err := io.ReadAll(io.LimitReader(resp.Body, maxOverpassBytes+1))
-	if err != nil {
-		return nil, errors.New("overpass answer could not be read")
-	}
-	if len(raw) > maxOverpassBytes {
-		return nil, errors.New("overpass answer is too large")
-	}
-	return raw, nil
-}
-
 func (a *API) mapRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("POST /v1/map/roads", a.ingest(a.mapRoads))
 }
@@ -332,17 +401,16 @@ func (a *API) mapRoads(w http.ResponseWriter, r *http.Request, c caller, body []
 	if *req.X < 0 || *req.X >= limit || *req.Y < 0 || *req.Y >= limit {
 		return invalid("x and y must be within the zoom level")
 	}
-	t := mapTile{Z: *req.Z, X: *req.X, Y: *req.Y}
+	// The car waits a few seconds at most; the fetch goes on without it.
-	data, cached, err := a.Maps.Tile(r.Context(), t)
+	wait, cancel := context.WithTimeout(r.Context(), mapWait)
+	defer cancel()
+	data, _, err := a.Maps.Tile(wait, mapTile{Z: *req.Z, X: *req.X, Y: *req.Y})
 	if err != nil {
-		slog.Warn("map tile not available", "installation", who(c), "error", err)
+		slog.Warn("map tile not available yet", "installation", who(c), "error", err)
-		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "map data not available, try again later"})
+		w.Header().Set("Retry-After", "10")
+		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "map data not available yet, try again shortly"})
 		return nil
 	}
-	if !cached {
-		slog.Info("map tile fetched", "installation", who(c), "ways", strings.Count(string(data), `"c":`),
-			"bytes", len(data))
-	}
 	w.Header().Set("Content-Type", "application/json")
 	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
 		var buf bytes.Buffer

server/maps_test.go

@@ -12,50 +12,140 @@ import (
 	"strings"
 	"sync/atomic"
 	"testing"
+	"time"
 )
 
 // A tile in central Berlin.
 var testTile = mapTile{Z: 14, X: 8802, Y: 5373}
 
-// fakeOverpass answers every query with a primary road (with a gap in its geometry), a
+// ---------- A minimal vector-tile encoder for the tests ----------
-// residential street with a needless middle point, and a footway the car does not draw.
+
-func fakeOverpass(t *testing.T, calls *atomic.Int32, status int) *httptest.Server {
+func pbVarint(v uint64) []byte {
-	t.Helper()
+	var b []byte
-	s, w, n, e := tileBounds(testTile)
+	for v >= 0x80 {
-	lat := func(f float64) float64 { return s + (n-s)*f }
+		b = append(b, byte(v)|0x80)
-	lon := func(f float64) float64 { return w + (e-w)*f }
+		v >>= 7
-	answer := fmt.Sprintf(`{"elements":[
-		{"type":"way","tags":{"highway":"primary"},"geometry":[
-			{"lat":%f,"lon":%f},{"lat":%f,"lon":%f},null,{"lat":%f,"lon":%f},{"lat":%f,"lon":%f}]},
-		{"type":"way","tags":{"highway":"residential"},"geometry":[
-			{"lat":%f,"lon":%f},{"lat":%f,"lon":%f},{"lat":%f,"lon":%f}]},
-		{"type":"way","tags":{"highway":"footway"},"geometry":[
-			{"lat":%f,"lon":%f},{"lat":%f,"lon":%f}]}]}`,
-		lat(0.1), lon(0.1), lat(0.2), lon(0.2), lat(0.6), lon(0.6), lat(0.7), lon(0.7),
-		lat(0.5), lon(0.1), lat(0.5), lon(0.5), lat(0.5), lon(0.9),
-		lat(0.3), lon(0.3), lat(0.4), lon(0.4))
-	return httptest.NewTLSServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
-		calls.Add(1)
-		if r.Method != http.MethodPost || !strings.Contains(r.UserAgent(), "nils-mg4-server") {
-			t.Errorf("request %s %q", r.Method, r.UserAgent())
 	}
-		_ = r.ParseForm()
+	return append(b, byte(v))
-		if q := r.PostForm.Get("data"); !strings.Contains(q, "out geom(") || !strings.Contains(q, "residential") {
-			t.Errorf("query %q", q)
-		}
-		if status != http.StatusOK {
-			http.Error(rw, "busy", status)
-			return
-		}
-		_, _ = rw.Write([]byte(answer))
-	}))
 }
 
-func mapsAPI(overpass *httptest.Server) http.Handler {
+func pbKey(num, wire int) []byte { return pbVarint(uint64(num<<3 | wire)) }
+
+func pbBytes(num int, data []byte) []byte {
+	return append(append(pbKey(num, 2), pbVarint(uint64(len(data)))...), data...)
+}
+
+func pbUint(num int, v uint64) []byte { return append(pbKey(num, 0), pbVarint(v)...) }
+
+func pbPacked(num int, vs []uint32) []byte {
+	var d []byte
+	for _, v := range vs {
+		d = append(d, pbVarint(uint64(v))...)
+	}
+	return pbBytes(num, d)
+}
+
+func zz(v int) uint32 { return uint32((v << 1) ^ (v >> 31)) }
+
+// lineCmds encodes line strings as MoveTo/LineTo commands with relative moves.
+func lineCmds(lines ...[][2]int) []uint32 {
+	var out []uint32
+	x, y := 0, 0
+	for _, l := range lines {
+		out = append(out, 1|1<<3, zz(l[0][0]-x), zz(l[0][1]-y))
+		x, y = l[0][0], l[0][1]
+		out = append(out, uint32(2|(len(l)-1)<<3))
+		for _, p := range l[1:] {
+			out = append(out, zz(p[0]-x), zz(p[1]-y))
+			x, y = p[0], p[1]
+		}
+	}
+	return out
+}
+
+type testFeature struct {
+	class    int // index into the values below
+	geomType uint64
+	geometry []uint32
+}
+
+// testVectorTile has a water layer (ignored) and a transportation layer with the given extent.
+func testVectorTile(extent uint64) []byte {
+	values := []string{"primary", "minor", "service", "motorway"}
+	features := []testFeature{
+		// A primary road with a needless middle point.
+		{0, 2, lineCmds([][2]int{{100, 100}, {200, 200}, {300, 300}})},
+		// A minor street in two pieces.
+		{1, 2, lineCmds([][2]int{{0, 500}, {400, 500}}, [][2]int{{600, 500}, {900, 520}})},
+		// A service road and a motorway as a polygon: neither is drawn.
+		{2, 2, lineCmds([][2]int{{10, 10}, {20, 20}})},
+		{3, 3, lineCmds([][2]int{{10, 10}, {20, 20}})},
+	}
+	var layer []byte
+	layer = append(layer, pbUint(15, 2)...)
+	layer = append(layer, pbBytes(1, []byte("transportation"))...)
+	for _, f := range features {
+		var feat []byte
+		feat = append(feat, pbPacked(2, []uint32{0, uint32(f.class)})...)
+		feat = append(feat, pbUint(3, f.geomType)...)
+		feat = append(feat, pbPacked(4, f.geometry)...)
+		layer = append(layer, pbBytes(2, feat)...)
+	}
+	layer = append(layer, pbBytes(3, []byte("class"))...)
+	for _, v := range values {
+		layer = append(layer, pbBytes(4, pbBytes(1, []byte(v)))...)
+	}
+	layer = append(layer, pbUint(5, extent)...)
+
+	water := append(pbBytes(1, []byte("water")), pbUint(5, 4096)...)
+	return append(pbBytes(3, water), pbBytes(3, layer)...)
+}
+
+// ---------- A fake tile host ----------
+
+type fakeHost struct {
+	*httptest.Server
+	tiles  atomic.Int32
+	status int
+	delay  time.Duration
+	gzip   bool
+}
+
+func newFakeHost(t *testing.T) *fakeHost {
+	t.Helper()
+	h := &fakeHost{status: http.StatusOK}
+	mux := http.NewServeMux()
+	mux.HandleFunc("GET /planet", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, `{"tilejson":"3.0.0","tiles":["%s/planet/build1/{z}/{x}/{y}.pbf"]}`, h.URL)
+	})
+	mux.HandleFunc("GET /planet/build1/{z}/{x}/{y}", func(w http.ResponseWriter, r *http.Request) {
+		h.tiles.Add(1)
+		if !strings.Contains(r.UserAgent(), "nils-mg4-server") {
+			t.Errorf("user agent %q", r.UserAgent())
+		}
+		time.Sleep(h.delay)
+		if h.status != http.StatusOK {
+			http.Error(w, "busy", h.status)
+			return
+		}
+		body := testVectorTile(4096)
+		if h.gzip {
+			var buf bytes.Buffer
+			zw := gzip.NewWriter(&buf)
+			_, _ = zw.Write(body)
+			_ = zw.Close()
+			body = buf.Bytes()
+		}
+		_, _ = w.Write(body)
+	})
+	h.Server = httptest.NewTLSServer(mux)
+	return h
+}
+
+func mapsAPIWith(host *fakeHost, cacheDir string) http.Handler {
 	api, _ := newTestAPI()
-	api.Maps = NewMaps(overpass.URL, mapUserAgent)
+	api.Maps = NewMaps(host.URL+"/planet", cacheDir, mapUserAgent)
-	api.Maps.Client = overpass.Client()
+	api.Maps.Client = host.Client()
-	api.Maps.gap = 0
 	return api.Routes()
 }
 
@@ -63,15 +153,8 @@ func tileBody(t mapTile) string {
 	return fmt.Sprintf(`{"z":%d,"x":%d,"y":%d}`, t.Z, t.X, t.Y)
 }
 
-func TestMapTileRoadsAreClassifiedSplitAndSimplified(t *testing.T) {
+func decodeAnswer(t *testing.T, rec *httptest.ResponseRecorder) roadTile {
-	var calls atomic.Int32
+	t.Helper()
-	overpass := fakeOverpass(t, &calls, http.StatusOK)
-	defer overpass.Close()
-	h := mapsAPI(overpass)
-	if rec := do(t, h, "POST", "/v1/map/roads", "", tileBody(testTile)); rec.Code != 401 {
-		t.Fatalf("without the car's token: %d", rec.Code)
-	}
-	rec := do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile))
 	if rec.Code != 200 {
 		t.Fatalf("%d %s", rec.Code, rec.Body)
 	}
@@ -79,39 +162,100 @@ func TestMapTileRoadsAreClassifiedSplitAndSimplified(t *testing.T) {
 	if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
 		t.Fatal(err)
 	}
-	if got.Extent != 4096 || got.X != testTile.X || got.Y != testTile.Y {
+	return got
-		t.Fatalf("tile %+v", got)
-	}
-	// The primary road in two pieces, the street straightened to its ends, no footway.
-	if len(got.Ways) != 3 || got.Ways[0].C != 1 || got.Ways[1].C != 1 || got.Ways[2].C != 3 {
-		t.Fatalf("ways %+v", got.Ways)
-	}
-	if len(got.Ways[2].P) != 4 {
-		t.Fatalf("the straight street keeps only its ends: %v", got.Ways[2].P)
-	}
-	// Tile-local: 0.1 of the way in is about 410 units from the west edge.
-	if x := got.Ways[0].P[0]; x < 400 || x > 420 {
-		t.Fatalf("x %d", x)
 }
 
-	// Cached: the second car asking costs Overpass nothing.
+// ---------- Tests ----------
-	if rec := do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile)); rec.Code != 200 {
+
-		t.Fatalf("%d", rec.Code)
+func TestVectorTileRoadsAreClassifiedSplitAndSimplified(t *testing.T) {
+	lines, err := decodeRoads(testVectorTile(4096))
+	if err != nil {
+		t.Fatal(err)
 	}
-	if calls.Load() != 1 {
+	if len(lines) != 3 || lines[0].class != 1 || lines[1].class != 3 || lines[2].class != 3 {
-		t.Fatalf("overpass asked %d times", calls.Load())
+		t.Fatalf("lines %+v", lines)
+	}
+	if fmt.Sprint(lines[1].points) != "[[0 500] [400 500]]" || fmt.Sprint(lines[2].points) != "[[600 500] [900 520]]" {
+		t.Fatalf("pieces %v %v", lines[1].points, lines[2].points)
+	}
+	// Another extent is scaled to 4096.
+	half, err := decodeRoads(testVectorTile(8192))
+	if err != nil || fmt.Sprint(half[0].points[2]) != "[150 150]" {
+		t.Fatalf("scaled %v %v", half, err)
+	}
+	body, err := buildTile(testTile, testVectorTile(4096))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(body), `{"c":1,"p":[100,100,300,300]}`) {
+		t.Fatalf("the straight road keeps only its ends: %s", body)
+	}
+}
+
+func TestMalformedVectorTilesAreRefused(t *testing.T) {
+	good := testVectorTile(4096)
+	for name, raw := range map[string][]byte{
+		"cut short":       good[:len(good)-7],
+		"bad wire type":   {0x1f, 0x00},
+		"length too long": {0x1a, 0x7f, 0x01},
+	} {
+		if _, err := decodeRoads(raw); err == nil {
+			t.Errorf("%s: accepted", name)
+		}
+	}
+	if lines, err := decodeRoads(nil); err != nil || len(lines) != 0 {
+		t.Fatalf("an empty tile is an empty map: %v %v", lines, err)
+	}
+}
+
+func TestMapTilesAreFetchedOnceAndKeptOnDisk(t *testing.T) {
+	host := newFakeHost(t)
+	host.gzip = true // some hosts gzip whatever was asked
+	defer host.Close()
+	dir := t.TempDir()
+	h := mapsAPIWith(host, dir)
+	if rec := do(t, h, "POST", "/v1/map/roads", "", tileBody(testTile)); rec.Code != 401 {
+		t.Fatalf("without the car's token: %d", rec.Code)
+	}
+	got := decodeAnswer(t, do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile)))
+	if got.Extent != 4096 || got.X != testTile.X || got.Y != testTile.Y || len(got.Ways) != 3 {
+		t.Fatalf("tile %+v", got)
+	}
+	decodeAnswer(t, do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile)))
+	// A restart: a new server with the same directory asks the host nothing.
+	decodeAnswer(t, do(t, mapsAPIWith(host, dir), "POST", "/v1/map/roads", testToken, tileBody(testTile)))
+	if n := host.tiles.Load(); n != 1 {
+		t.Fatalf("tile fetched %d times", n)
+	}
+}
+
+func TestASlowTileIsFinishedForTheCarsNextTry(t *testing.T) {
+	previous := mapWait
+	mapWait = 50 * time.Millisecond
+	defer func() { mapWait = previous }()
+	host := newFakeHost(t)
+	host.delay = 300 * time.Millisecond
+	defer host.Close()
+	h := mapsAPIWith(host, "")
+	rec := do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile))
+	if rec.Code != 503 || rec.Header().Get("Retry-After") == "" {
+		t.Fatalf("the car should hear 'try again': %d", rec.Code)
+	}
+	time.Sleep(600 * time.Millisecond)
+	decodeAnswer(t, do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile)))
+	if n := host.tiles.Load(); n != 1 {
+		t.Fatalf("tile fetched %d times", n)
 	}
 }
 
 func TestMapTilesAreGzippedWhenTheCarAcceptsIt(t *testing.T) {
-	var calls atomic.Int32
+	host := newFakeHost(t)
-	overpass := fakeOverpass(t, &calls, http.StatusOK)
+	defer host.Close()
-	defer overpass.Close()
 	req := httptest.NewRequest("POST", "/v1/map/roads", strings.NewReader(tileBody(testTile)))
 	req.Header.Set("Authorization", "Bearer "+testToken)
 	req.Header.Set("Accept-Encoding", "gzip")
 	rec := httptest.NewRecorder()
-	mapsAPI(overpass).ServeHTTP(rec, req)
+	mapsAPIWith(host, "").ServeHTTP(rec, req)
 	if rec.Code != 200 || rec.Header().Get("Content-Encoding") != "gzip" {
 		t.Fatalf("%d %v", rec.Code, rec.Header())
 	}
@@ -126,84 +270,89 @@ func TestMapTilesAreGzippedWhenTheCarAcceptsIt(t *testing.T) {
 }
 
 func TestMapRequestsAreChecked(t *testing.T) {
-	var calls atomic.Int32
+	host := newFakeHost(t)
-	overpass := fakeOverpass(t, &calls, http.StatusOK)
+	defer host.Close()
-	defer overpass.Close()
+	h := mapsAPIWith(host, "")
-	h := mapsAPI(overpass)
 	for _, body := range []string{`{}`, `{"z":15,"x":1,"y":1}`, `{"z":14,"x":-1,"y":1}`,
 		`{"z":14,"x":1,"y":16384}`, `not json`} {
 		if rec := do(t, h, "POST", "/v1/map/roads", testToken, body); rec.Code != 400 {
 			t.Errorf("%s: %d", body, rec.Code)
 		}
 	}
-	if calls.Load() != 0 {
+	if host.tiles.Load() != 0 {
-		t.Fatal("a bad request reached Overpass")
+		t.Fatal("a bad request reached the tile host")
 	}
 }
 
-func TestABusyOverpassIsATemporaryFailureAndNotCached(t *testing.T) {
+func TestAFailingHostIsATemporaryFailureAndNotCached(t *testing.T) {
 	var logged bytes.Buffer
 	previous := slog.Default()
 	slog.SetDefault(slog.New(slog.NewTextHandler(&logged, nil)))
 	defer slog.SetDefault(previous)
 
-	var calls atomic.Int32
+	host := newFakeHost(t)
-	overpass := fakeOverpass(t, &calls, http.StatusTooManyRequests)
+	host.status = http.StatusBadGateway
-	defer overpass.Close()
+	defer host.Close()
-	h := mapsAPI(overpass)
+	h := mapsAPIWith(host, t.TempDir())
 	for i := 0; i < 2; i++ {
 		if rec := do(t, h, "POST", "/v1/map/roads", testToken, tileBody(testTile)); rec.Code != 503 {
 			t.Fatalf("%d", rec.Code)
 		}
 	}
-	if calls.Load() != 2 {
+	if n := host.tiles.Load(); n != 2 {
-		t.Fatalf("a failure was cached: %d calls", calls.Load())
+		t.Fatalf("a failure was cached: %d fetches", n)
 	}
 	// Where the car is stays out of the log.
 	out := logged.String()
-	if !strings.Contains(out, "overpass answered 429") || strings.Contains(out, "8802") ||
+	if !strings.Contains(out, "tile host answered 502") || strings.Contains(out, "8802") ||
 		strings.Contains(out, "5373") {
 		t.Fatalf("log:\n%s", out)
 	}
 }
 
-func TestMapsAreOffWithoutOverpass(t *testing.T) {
+func TestATileIndexWithoutHttpsIsRefused(t *testing.T) {
+	index := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte(`{"tiles":["http://tiles.example.com/{z}/{x}/{y}.pbf"]}`))
+	}))
+	defer index.Close()
+	api, _ := newTestAPI()
+	api.Maps = NewMaps(index.URL, "", mapUserAgent)
+	api.Maps.Client = index.Client()
+	if rec := do(t, api.Routes(), "POST", "/v1/map/roads", testToken, tileBody(testTile)); rec.Code != 503 {
+		t.Fatalf("%d", rec.Code)
+	}
+}
+
+func TestMapsAreOffWithoutATileSource(t *testing.T) {
 	api, _ := newTestAPI()
 	if rec := do(t, api.Routes(), "POST", "/v1/map/roads", testToken, tileBody(testTile)); rec.Code != 404 {
 		t.Fatalf("%d", rec.Code)
 	}
 }
 
-func TestOverpassURLConfiguration(t *testing.T) {
+func TestMapTilesURLConfiguration(t *testing.T) {
 	base := map[string]string{"INFLUX_URL": "http://influx", "INFLUX_TOKEN": "t", "INFLUX_ORG": "o",
 		"INGEST_TOKEN": "0123456789abcdef01234567"}
-	load := func(overpass string) (config, error) {
+	load := func(tiles string) (config, error) {
 		return loadConfig(func(k string) string {
-			if k == "OVERPASS_URL" {
+			if k == "MAP_TILES_URL" {
-				return overpass
+				return tiles
 			}
 			return base[k]
 		})
 	}
-	if c, err := load(""); err != nil || c.overpassURL != DefaultOverpassURL {
+	if c, err := load(""); err != nil || c.mapTilesURL != DefaultMapTilesURL {
-		t.Fatalf("default: %q %v", c.overpassURL, err)
+		t.Fatalf("default: %q %v", c.mapTilesURL, err)
 	}
-	if c, err := load("off"); err != nil || c.overpassURL != "" {
+	if c, err := load("off"); err != nil || c.mapTilesURL != "" {
-		t.Fatalf("off: %q %v", c.overpassURL, err)
+		t.Fatalf("off: %q %v", c.mapTilesURL, err)
 	}
-	if _, err := load("http://overpass.example.com/api/interpreter"); err == nil {
+	if _, err := load("http://tiles.example.com/planet"); err == nil {
 		t.Fatal("plain http accepted")
 	}
 }
 
-func TestTilePointsAndSimplification(t *testing.T) {
+func TestSimplification(t *testing.T) {
-	s, w, n, e := tileBounds(testTile)
-	if x, y := tilePoint(testTile, n, w); x != 0 || y != 0 {
-		t.Fatalf("north-west corner %d,%d", x, y)
-	}
-	if x, y := tilePoint(testTile, s, e); x != 4096 || y != 4096 {
-		t.Fatalf("south-east corner %d,%d", x, y)
-	}
 	line := [][2]int{{0, 0}, {10, 1}, {20, 0}, {30, 40}}
 	got := simplify(line, 4)
 	if len(got) != 3 || got[1] != [2]int{20, 0} {

server/mvt.go

@@ -0,0 +1,278 @@
+package main
+
+import (
+	"errors"
+	"math"
+)
+
+// The roads of a Mapbox Vector Tile (spec 2.1) in the OpenMapTiles schema: the line features
+// of the "transportation" layer whose "class" the car draws (roadClasses), scaled to
+// mapExtent. A minimal protobuf reader, enough for that and nothing more; anything malformed
+// is an error, never a guess.
+
+type roadLine struct {
+	class  int
+	points [][2]int
+}
+
+var errBadTile = errors.New("vector tile is malformed")
+
+// pbReader walks protobuf fields.
+type pbReader struct {
+	b []byte
+	i int
+}
+
+func (r *pbReader) done() bool { return r.i >= len(r.b) }
+
+func (r *pbReader) varint() (uint64, error) {
+	var v uint64
+	for shift := uint(0); shift < 64; shift += 7 {
+		if r.i >= len(r.b) {
+			return 0, errBadTile
+		}
+		c := r.b[r.i]
+		r.i++
+		v |= uint64(c&0x7f) << shift
+		if c < 0x80 {
+			return v, nil
+		}
+	}
+	return 0, errBadTile
+}
+
+// field reads one field's key and, for length-delimited ones, its bytes.
+func (r *pbReader) field() (num int, wire int, val uint64, data []byte, err error) {
+	key, err := r.varint()
+	if err != nil {
+		return 0, 0, 0, nil, err
+	}
+	num, wire = int(key>>3), int(key&7)
+	switch wire {
+	case 0:
+		val, err = r.varint()
+	case 1:
+		if r.i+8 > len(r.b) {
+			return 0, 0, 0, nil, errBadTile
+		}
+		r.i += 8
+	case 2:
+		var n uint64
+		n, err = r.varint()
+		if err == nil {
+			if n > uint64(len(r.b)-r.i) {
+				return 0, 0, 0, nil, errBadTile
+			}
+			data = r.b[r.i : r.i+int(n)]
+			r.i += int(n)
+		}
+	case 5:
+		if r.i+4 > len(r.b) {
+			return 0, 0, 0, nil, errBadTile
+		}
+		r.i += 4
+	default:
+		return 0, 0, 0, nil, errBadTile
+	}
+	return num, wire, val, data, err
+}
+
+// packed reads a repeated uint32 field, packed or not.
+func packed(wire int, val uint64, data []byte, into []uint32) ([]uint32, error) {
+	if wire == 0 {
+		return append(into, uint32(val)), nil
+	}
+	if wire != 2 {
+		return nil, errBadTile
+	}
+	r := pbReader{b: data}
+	for !r.done() {
+		v, err := r.varint()
+		if err != nil {
+			return nil, err
+		}
+		into = append(into, uint32(v))
+	}
+	return into, nil
+}
+
+// decodeRoads returns the drawable roads of the tile.
+func decodeRoads(tile []byte) ([]roadLine, error) {
+	r := pbReader{b: tile}
+	for !r.done() {
+		num, _, _, data, err := r.field()
+		if err != nil {
+			return nil, err
+		}
+		if num != 3 { // layers
+			continue
+		}
+		lines, isRoads, err := decodeLayer(data)
+		if err != nil {
+			return nil, err
+		}
+		if isRoads {
+			return lines, nil
+		}
+	}
+	return nil, nil // a tile without roads (sea, desert) is an empty one
+}
+
+type rawFeature struct {
+	tags     []uint32
+	geomType uint64
+	geometry []uint32
+}
+
+func decodeLayer(layer []byte) ([]roadLine, bool, error) {
+	r := pbReader{b: layer}
+	var name string
+	var keys []string
+	var values []string // only string values matter for "class"
+	var features []rawFeature
+	extent := uint64(4096)
+	for !r.done() {
+		num, wire, val, data, err := r.field()
+		if err != nil {
+			return nil, false, err
+		}
+		switch num {
+		case 1:
+			name = string(data)
+		case 2:
+			f, err := decodeFeature(data)
+			if err != nil {
+				return nil, false, err
+			}
+			features = append(features, f)
+		case 3:
+			keys = append(keys, string(data))
+		case 4:
+			values = append(values, valueString(data))
+		case 5:
+			if wire != 0 || val == 0 {
+				return nil, false, errBadTile
+			}
+			extent = val
+		}
+	}
+	if name != "transportation" {
+		return nil, false, nil
+	}
+	scale := float64(mapExtent) / float64(extent)
+	var lines []roadLine
+	for _, f := range features {
+		if f.geomType != 2 { // LINESTRING
+			continue
+		}
+		class, ok := -1, false
+		for i := 0; i+1 < len(f.tags); i += 2 {
+			k, v := int(f.tags[i]), int(f.tags[i+1])
+			if k >= len(keys) || v >= len(values) {
+				return nil, false, errBadTile
+			}
+			if keys[k] == "class" {
+				class, ok = roadClasses[values[v]]
+				if !ok {
+					class = -1
+				}
+			}
+		}
+		if class < 0 {
+			continue
+		}
+		parts, err := lineGeometry(f.geometry, scale)
+		if err != nil {
+			return nil, false, err
+		}
+		for _, p := range parts {
+			lines = append(lines, roadLine{class: class, points: p})
+		}
+	}
+	return lines, true, nil
+}
+
+func decodeFeature(data []byte) (rawFeature, error) {
+	var f rawFeature
+	r := pbReader{b: data}
+	for !r.done() {
+		num, wire, val, d, err := r.field()
+		if err != nil {
+			return f, err
+		}
+		switch num {
+		case 2:
+			if f.tags, err = packed(wire, val, d, f.tags); err != nil {
+				return f, err
+			}
+		case 3:
+			f.geomType = val
+		case 4:
+			if f.geometry, err = packed(wire, val, d, f.geometry); err != nil {
+				return f, err
+			}
+		}
+	}
+	if len(f.tags)%2 != 0 {
+		return f, errBadTile
+	}
+	return f, nil
+}
+
+// valueString is a Value's string_value, "" for any other kind.
+func valueString(data []byte) string {
+	r := pbReader{b: data}
+	for !r.done() {
+		num, _, _, d, err := r.field()
+		if err != nil {
+			return ""
+		}
+		if num == 1 {
+			return string(d)
+		}
+	}
+	return ""
+}
+
+// lineGeometry follows the MoveTo/LineTo commands of a (multi)line string.
+func lineGeometry(cmds []uint32, scale float64) ([][][2]int, error) {
+	var parts [][][2]int
+	var cur [][2]int
+	x, y := 0, 0
+	zig := func(v uint32) int { return int(int32(v>>1) ^ -int32(v&1)) }
+	at := func() [2]int {
+		return [2]int{int(math.Round(float64(x) * scale)), int(math.Round(float64(y) * scale))}
+	}
+	for i := 0; i < len(cmds); {
+		id, count := cmds[i]&7, int(cmds[i]>>3)
+		i++
+		switch id {
+		case 1, 2: // MoveTo, LineTo
+			if i+2*count > len(cmds) {
+				return nil, errBadTile
+			}
+			for k := 0; k < count; k++ {
+				x += zig(cmds[i])
+				y += zig(cmds[i+1])
+				i += 2
+				if id == 1 {
+					if len(cur) >= 2 {
+						parts = append(parts, cur)
+					}
+					cur = [][2]int{at()}
+				} else {
+					if p := at(); len(cur) == 0 || cur[len(cur)-1] != p {
+						cur = append(cur, p)
+					}
+				}
+			}
+		case 7: // ClosePath, not in a line; ignored
+		default:
+			return nil, errBadTile
+		}
+	}
+	if len(cur) >= 2 {
+		parts = append(parts, cur)
+	}
+	return parts, nil
+}