package com.evsuite.abrp;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.Typeface;
import android.os.SystemClock;

/**
 * The Grid Overview style, after the neon world of the Tron films: glowing lines on black, a
 * perspective grid floor that runs towards you with the speed, and shapes with cut corners.
 *
 * Centre: the speed, large and thin. Left: the battery as a segmented light wall standing on
 * the floor, with the charge and range beside it. Right: power on a disc — the ring lights from
 * the top, clockwise while drawing and anticlockwise while regenerating, and its inner ring
 * turns with the power. On the floor, the last two minutes of power as a light-cycle trail,
 * which only ever turns at right angles. P R N D as tiles on top, the clock top right, and a
 * row of read-outs along the bottom. Unread values show "—", light nothing and leave gaps in
 * 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
 * under everything, heading up, the bigger ones glowing brighter, with the car as a light
 * marker low on the screen; between GPS fixes the car's position runs on
 * with the speed. The map is then the whole background, straight from above (about
 * 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
 * low battery is orange in the original (the films' other side) and white in the accent one,
 * so it never looks like the accent itself. The floor and the disc animate (about 30 frames a
 * second) only while the car moves and the view is on screen.
 */
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;

    private final Paint line = new Paint(Paint.ANTI_ALIAS_FLAG);
    private final Paint fill = new Paint(Paint.ANTI_ALIAS_FLAG);
    private final Paint text = new Paint(Paint.ANTI_ALIAS_FLAG);
    private final Paint sky = new Paint();
    private final Path path = new Path();
    private android.graphics.DashPathEffect dash;
    private float dashFor;
    private final RectF r = new RectF();
    private final Typeface thin = Typeface.create("sans-serif-thin", Typeface.NORMAL);
    private final Typeface label = Typeface.create("sans-serif-condensed", Typeface.BOLD);
    private final int accent, accentLight;
    /** Null for the plain Grid. */
    private final MapRoads map;
    /** The map under this view (a hardware layer, moved by the GPU); null for the plain Grid. */
    private final MapLayerView mapLayer;
    private final Paint fade = new Paint();
    private int fadeFor = -1;

    private int main, light, dim, alert;
    /** The floor's position within one tile (0..1) and the disc's inner ring angle. */
    private float floorPhase, discTurn;
    private long lastFrame;
    private int skyFor = -1;

    GridView(Context context) {
        this(context, null);
    }

    GridView(Context context, MapRoads map) {
        super(context);
        this.map = map;
        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);
        line.setStrokeCap(Paint.Cap.SQUARE);
        line.setStrokeJoin(Paint.Join.MITER);
        setAccentPalette(false);
    }

    /** The chosen accent colour instead of the original cyan. */
    void setAccentPalette(boolean useAccent) {
        main = useAccent ? accent : 0xFF18E6FF;
        light = useAccent ? accentLight : 0xFFC8FCFF;
        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);
        float w = getWidth(), h = getHeight();
        if (w <= 0 || h <= 0) return;
        float u = Math.min(h / 640f, w / 1100f);
        advance();
        // 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);
        }
        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);
        if (mapShown) drawMapSpeed(c, w, u);
        else drawSpeed(c, w, horizon, u);
        drawWall(c, horizon, 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;
        // Over the map only the readings change; the map layer moves itself.
        keepAnimating(moving && !mapShown, 33);
    }

    /** Moves the floor by the distance driven since the last frame, and turns the disc. */
    private void advance() {
        long now = SystemClock.uptimeMillis();
        float dt = lastFrame == 0 ? 0f : Math.min(0.2f, (now - lastFrame) / 1000f);
        lastFrame = now;
        if (v.speedKmh != null && v.speedKmh > 0.5f) {
            floorPhase = (floorPhase + v.speedKmh / 3.6f * dt / TILE_M) % 1f;
        }
        if (v.powerKw != null) discTurn = (discTurn + v.powerKw * 3f * dt) % 360f;
    }

    // ---------- Floor ----------

    private void drawSky(Canvas c, float w, float horizon) {
        if (skyFor != (int) horizon) {
            sky.setShader(new LinearGradient(0, horizon - horizon * 0.45f, 0, horizon,
                    0x00000000, AccentColor.withAlpha(main, 0x30), Shader.TileMode.CLAMP));
            skyFor = (int) horizon;
        }
        c.drawRect(0, horizon - horizon * 0.45f, w, horizon, sky);
    }

    /** Lines converging on the horizon, and cross lines that run towards the viewer. */
    private void drawFloor(Canvas c, float w, float h, float horizon, float u) {
        float vx = w / 2f, depth = h - horizon;
        line.setStrokeWidth(1.2f * u);
        for (int i = -14; i <= 14; i++) {
            float bottomX = vx + i * w * 0.09f;
            line.setColor(AccentColor.withAlpha(main, 0x38));
            c.drawLine(vx + (bottomX - vx) * 0.02f, horizon, bottomX, h, line);
        }
        for (int k = 0; k < 24; k++) {
            float d = k + 1f - floorPhase;
            if (d <= 0.05f) continue;
            float y = horizon + depth / d;
            if (y > h || y < horizon + 1f) continue;
            float near = (y - horizon) / depth;
            line.setColor(AccentColor.withAlpha(main, (int) (0x10 + 0x50 * near)));
            c.drawLine(0, y, w, y, line);
        }
        glowLine(c, 0, horizon, w, horizon, main, 1.5f * u);
    }

    // ---------- Map ----------

    /** Over the map: the far roads fading into the dark towards the top, and the car. */
    private void drawCar(Canvas c, float w, float h, float u) {
        float carSx = w / 2f, carSy = h - MapLayerView.CAR_FROM_BOTTOM * u;
        if (fadeFor != (int) (carSy + h)) {
            fade.setShader(new LinearGradient(0, 0, 0, carSy, 0xB0000000, 0x00000000, Shader.TileMode.CLAMP));
            fadeFor = (int) (carSy + h);
        }
        c.drawRect(0, 0, w, carSy, fade);
        // A light-cycle chevron pointing ahead.
        path.reset();
        path.moveTo(carSx, carSy - 18f * u);
        path.lineTo(carSx + 12f * u, carSy + 11f * u);
        path.lineTo(carSx, carSy + 5f * 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);
    }

    /** Dark panels under the battery wall and the clock, so the map does not run through them. */
    private void drawPanels(Canvas c, float w, float horizon, float u) {
        chamfer(16f * u, 78f * u, 360f * u, horizon + 86f * u, 14f * u);
        fill.setColor(0xC8000000);
        c.drawPath(path, fill);
        chamfer(w - 210f * u, 12f * u, w - 12f * u, 82f * u, 10f * u);
        c.drawPath(path, fill);
        // Behind the gears as well.
        chamfer(w / 2f - 150f * u, 12f * u, w / 2f + 150f * u, 72f * u, 10f * u);
        c.drawPath(path, fill);
    }

    /** The speed over the map: smaller, on a panel under the gears. */
    private void drawMapSpeed(Canvas c, float w, float u) {
        chamfer(w / 2f - 130f * u, 80f * u, w / 2f + 130f * u, 232f * u, 14f * u);
        fill.setColor(0xC8000000);
        c.drawPath(path, fill);
        line.setColor(dim);
        line.setStrokeWidth(1.5f * u);
        c.drawPath(path, line);
        text.setTypeface(thin);
        text.setTextSize(120f * u);
        text.setTextAlign(Paint.Align.CENTER);
        glowText(c, fmt(v.speedKmh, "%.0f", "—"), w / 2f, 194f * u, light, u);
        caption(c, "KM/H", w / 2f, 220f * u, u, Paint.Align.CENTER);
    }

    /** Why the map is not there, on the floor. */
    private void drawMapState(Canvas c, float w, float h, float horizon, float u) {
        MapRoads.State state = map.state();
        String why = state == MapRoads.State.NO_SERVER ? "MAP · SET UP THE SERVER FIRST"
                : state == MapRoads.State.WAITING_FOR_GPS ? "MAP · WAITING FOR GPS"
                : state == MapRoads.State.UNAVAILABLE ? "MAP · NOT AVAILABLE, TRYING AGAIN"
                : "MAP · LOADING";
        caption(c, why, w / 2f, horizon + (h - horizon) * 0.2f, u, Paint.Align.CENTER);
    }

    /** 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("OpenFreeMap © OpenMapTiles · © OpenStreetMap contributors", w - 26f * u, h - 80f * u, text);
    }

    // ---------- Top ----------

    private void drawGears(Canvas c, float w, float u) {
        String[] gears = { "P", "R", "N", "D" };
        String now = Gear.label(v.gear);
        float tw = 58f * u, th = 40f * u, gap = 12f * u;
        float x = w / 2f - (gears.length * tw + (gears.length - 1) * gap) / 2f, top = 22f * u;
        text.setTypeface(label);
        text.setTextSize(24f * u);
        text.setTextAlign(Paint.Align.CENTER);
        for (String g : gears) {
            boolean on = g.equals(now);
            chamfer(x, top, x + tw, top + th, 9f * u);
            if (on) {
                fill.setColor(main);
                c.drawPath(path, fill);
                glow(c, path, main, 1.5f * u);
            } else {
                line.setColor(dim);
                line.setStrokeWidth(1.5f * u);
                c.drawPath(path, line);
            }
            text.setColor(on ? 0xFF000000 : dim);
            c.drawText(g, x + tw / 2f, top + th * 0.72f, text);
            x += tw + gap;
        }
    }

    private void drawClock(Canvas c, float w, float u) {
        text.setTypeface(thin);
        text.setTextSize(44f * u);
        text.setTextAlign(Paint.Align.RIGHT);
        glowText(c, v.clock.isEmpty() ? "—" : v.clock, w - 28f * u, 62f * u, light, u);
    }

    // ---------- Speed ----------

    private void drawSpeed(Canvas c, float w, float horizon, float u) {
        text.setTypeface(thin);
        text.setTextSize(210f * u);
        text.setTextAlign(Paint.Align.CENTER);
        glowText(c, fmt(v.speedKmh, "%.0f", "—"), w / 2f, horizon - 62f * u, light, u);
        caption(c, "KM/H", w / 2f, horizon - 22f * u, u, Paint.Align.CENTER);
    }

    // ---------- Battery wall ----------

    private void drawWall(Canvas c, float horizon, float u) {
        boolean low = v.socPercent != null && v.socPercent < 20f;
        int colour = low ? alert : main;
        float left = 34f * u, right = left + 52f * u, top = 96f * u, bottom = horizon + 70f * u;
        float seg = (bottom - top) / WALL;
        int lit = v.socPercent == null ? 0 : Math.round(v.socPercent / 100f * WALL);
        for (int i = 0; i < WALL; i++) {
            float b = bottom - i * seg, t = b - seg + 3f * u;
            r.set(left, t, right, b);
            if (i < lit) {
                fill.setColor(i == lit - 1 ? light : colour);
                c.drawRect(r, fill);
            } else {
                line.setColor(dim);
                line.setStrokeWidth(1f * u);
                c.drawRect(r, line);
            }
        }
        chamfer(left - 8f * u, top - 8f * u, right + 8f * u, bottom + 8f * u, 10f * u);
        glow(c, path, colour, 1.5f * u);

        float x = right + 30f * u;
        caption(c, low ? "LOW ENERGY" : "ENERGY", x, top + 18f * u, u, Paint.Align.LEFT);
        text.setTypeface(thin);
        text.setTextSize(96f * u);
        text.setTextAlign(Paint.Align.LEFT);
        String soc = fmt(v.socPercent, "%.0f", "—");
        glowText(c, soc, x, top + 116f * u, low ? alert : light, u);
        float socWidth = text.measureText(soc);
        text.setTextSize(36f * u);
        glowText(c, "%", x + socWidth + 8f * u, top + 116f * u, colour, u);
        caption(c, "RANGE", x, top + 168f * u, u, Paint.Align.LEFT);
        text.setTypeface(thin);
        text.setTextSize(52f * u);
        glowText(c, fmt(v.rangeKm, "%.0f km", "—"), x, top + 222f * u, light, u);
    }

    // ---------- Power disc ----------

    /** Zero at the top, −50 kW a quarter turn anticlockwise, 150 kW three quarters clockwise. */
    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);
        float sweepPerKw = 270f / 200f;
        float power = v.powerKw == null ? 0f : Math.max(-50f, Math.min(150f, v.powerKw));
        float segDeg = 270f / DISC;
        for (int i = 0; i < DISC; i++) {
            // Segment i covers −50 + i·(200/DISC) … one step more, drawn from −135° (top-left).
            float kwFrom = -50f + i * 200f / DISC, kwTo = kwFrom + 200f / DISC;
            boolean on = v.powerKw != null
                    && (power >= 0 ? kwFrom >= 0f && kwFrom < power : kwTo <= 0f && kwTo > power);
            float start = -90f + kwFrom * sweepPerKw;
            r.set(cx - outer + ring / 2f, cy - outer + ring / 2f, cx + outer - ring / 2f, cy + outer - ring / 2f);
            line.setStrokeWidth(ring);
            line.setStrokeCap(Paint.Cap.BUTT);
            line.setColor(on ? (power < 0 ? light : main) : AccentColor.withAlpha(main, 0x22));
            c.drawArc(r, start + 0.6f, segDeg - 1.2f, false, line);
        }
        line.setStrokeCap(Paint.Cap.SQUARE);
        // The zero mark, and an inner ring of dashes that turns with the power.
        glowLine(c, cx, cy - outer - 16f * u, cx, cy - outer + ring + 6f * u, light, 2f * u);
        float inner = outer - ring - 22f * u;
        line.setStrokeWidth(3f * u);
        line.setColor(main);
        r.set(cx - inner, cy - inner, cx + inner, cy + inner);
        for (int k = 0; k < 8; k++) c.drawArc(r, discTurn + k * 45f, 26f, false, line);
        line.setColor(dim);
        line.setStrokeWidth(1f * u);
        c.drawCircle(cx, cy, inner - 12f * u, line);

        text.setTypeface(thin);
        text.setTextSize(64f * u);
        text.setTextAlign(Paint.Align.CENTER);
        glowText(c, fmt(v.powerKw, "%.1f", "—"), cx, cy + 18f * u, light, u);
        caption(c, v.powerKw != null && v.powerKw < 0f ? "KW · REGEN" : "KW", cx, cy + 50f * u, u,
                Paint.Align.CENTER);
        caption(c, "POWER", cx, cy - 46f * u, u, Paint.Align.CENTER);
    }

    // ---------- Light trail ----------

    /** Power over the last two minutes as a trail of right angles; NaN breaks it. */
    private void drawTrail(Canvas c, float w, float h, float u) {
        float[] trail = v.powerTrail;
        float left = 300f * u, right = w - 360f * u, top = h * 0.66f, bottom = h * 0.84f;
        if (right - left < 200f * u) return;
        float max = 10f, min = -10f;
        if (trail != null) {
            for (float p : trail) {
                if (Float.isNaN(p)) continue;
                max = Math.max(max, (float) Math.ceil(p / 10f) * 10f);
                min = Math.min(min, (float) Math.floor(p / 10f) * 10f);
            }
        }
        float zero = bottom - (0f - min) / (max - min) * (bottom - top);
        line.setColor(dim);
        line.setStrokeWidth(1f * u);
        if (dash == null || dashFor != u) {
            dash = new android.graphics.DashPathEffect(new float[] { 6f * u, 8f * u }, 0);
            dashFor = u;
        }
        line.setPathEffect(dash);
        c.drawLine(left, zero, right, zero, line);
        line.setPathEffect(null);
        caption(c, "POWER · LAST 2 MIN", left, top - 10f * u, u, Paint.Align.LEFT);
        if (trail == null || trail.length < 2) return;

        float step = (right - left) / (trail.length - 1);
        path.reset();
        boolean open = false;
        float lastX = 0, lastY = 0;
        for (int i = 0; i < trail.length; i++) {
            float p = trail[i];
            if (Float.isNaN(p)) {
                open = false;
                continue;
            }
            float x = left + i * step, y = bottom - (p - min) / (max - min) * (bottom - top);
            if (!open) {
                path.moveTo(x, y);
                open = true;
            } else {
                path.lineTo(x, lastY); // along, then a right angle
                path.lineTo(x, y);
            }
            lastX = x;
            lastY = y;
        }
        glow(c, path, main, 2.5f * u);
        if (open) {
            fill.setColor(light);
            c.drawCircle(lastX, lastY, 5f * u, fill);
            fill.setColor(AccentColor.withAlpha(main, 0x50));
            c.drawCircle(lastX, lastY, 12f * u, fill);
        }
    }

    // ---------- Read-outs ----------

    private void drawReadouts(Canvas c, float w, float h, float u) {
        String[][] cells = {
                { "USAGE · 5 MIN", fmt(v.usage5Min, "%.1f", "—") },
                { "SINCE START", fmt(v.usageTrip, "%.1f", "—") },
                { "TRIP", fmt(v.tripKm, "%.1f km", "—") },
                { "CLIMATE", fmt(v.climateCelsius, "%.0f °C", "—") },
                { "ODOMETER", fmt(v.odometerKm, "%,.0f km", "—") },
        };
        float margin = 24f * u, gap = 14f * u, top = h - 70f * u, bottom = h - 14f * u;
        float cw = (w - 2 * margin - (cells.length - 1) * gap) / cells.length;
        for (int i = 0; i < cells.length; i++) {
            float l = margin + i * (cw + gap);
            chamfer(l, top, l + cw, bottom, 10f * u);
            fill.setColor(0xE6000000);
            c.drawPath(path, fill);
            line.setColor(dim);
            line.setStrokeWidth(1.5f * u);
            c.drawPath(path, line);
            caption(c, cells[i][0], l + 16f * u, top + 20f * u, u, Paint.Align.LEFT);
            text.setTypeface(thin);
            text.setTextSize(30f * u);
            text.setTextAlign(Paint.Align.RIGHT);
            glowText(c, cells[i][1], l + cw - 16f * u, bottom - 10f * u, light, u);
        }
    }

    // ---------- Light ----------

    /** A rectangle with its top-left and bottom-right corners cut, into [path]. */
    private void chamfer(float l, float t, float rr, float b, float cut) {
        path.reset();
        path.moveTo(l + cut, t);
        path.lineTo(rr, t);
        path.lineTo(rr, b - cut);
        path.lineTo(rr - cut, b);
        path.lineTo(l, b);
        path.lineTo(l, t + cut);
        path.close();
    }

    /** A line that glows: two wide faint strokes under a sharp one. */
    private void glow(Canvas c, Path p, int colour, float width) {
        line.setColor(AccentColor.withAlpha(colour, 0x18));
        line.setStrokeWidth(width * 6f);
        c.drawPath(p, line);
        line.setColor(AccentColor.withAlpha(colour, 0x40));
        line.setStrokeWidth(width * 3f);
        c.drawPath(p, line);
        line.setColor(colour);
        line.setStrokeWidth(width);
        c.drawPath(p, line);
    }

    private void glowLine(Canvas c, float x1, float y1, float x2, float y2, int colour, float width) {
        path.reset();
        path.moveTo(x1, y1);
        path.lineTo(x2, y2);
        glow(c, path, colour, width);
    }

    /** Text with a halo: a wide faint outline under the letters. */
    private void glowText(Canvas c, String s, float x, float y, int colour, float u) {
        text.setStyle(Paint.Style.STROKE);
        text.setStrokeWidth(7f * u);
        text.setColor(AccentColor.withAlpha(colour, 0x30));
        c.drawText(s, x, y, text);
        text.setStyle(Paint.Style.FILL);
        text.setColor(colour);
        c.drawText(s, x, y, text);
    }

    /** A small label in spaced capitals. */
    private void caption(Canvas c, String s, float x, float y, float u, Paint.Align align) {
        text.setTypeface(label);
        text.setTextSize(15f * u);
        text.setLetterSpacing(0.2f);
        text.setTextAlign(align);
        text.setStyle(Paint.Style.FILL);
        text.setColor(main);
        c.drawText(s, x, y, text);
        text.setLetterSpacing(0f);
    }
}