Library: mark titles that are downloading

While the Library is visible it reads the Radarr and Sonarr queues (on
opening, every 10 s, and shortly after a grab) and matches them to the
titles by movieId / seriesId. Those titles get a blue dot instead of the
green or grey one, and their details say how far the download is.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/ui/libqueue.go

@@ -0,0 +1,105 @@
+package ui
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"git.stinnesbeck.com/nils/arr-tui/internal/arr"
+)
+
+// libQueueInterval is how often the Library asks for the download queues
+// while it is visible.
+const libQueueInterval = 10 * time.Second
+
+// dlInfo says that a library title is in the Radarr/Sonarr download queue.
+type dlInfo struct {
+	count    int     // queue entries (episodes of a series)
+	progress float64 // percent, of the first entry
+	timeLeft string  // of the first entry
+}
+
+// dlLine is the details pane line for a title in the queue.
+func (d dlInfo) dlLine() string {
+	if d.count > 1 {
+		return fmt.Sprintf("[blue]Downloading[-] %d episodes\n", d.count)
+	}
+	line := fmt.Sprintf("[blue]Downloading[-] %.0f%%", d.progress)
+	if d.timeLeft != "" {
+		line += " · " + d.timeLeft + " left"
+	}
+	return line + "\n"
+}
+
+// queueByTitle groups queue entries by the library title they belong to.
+func queueByTitle(items []arr.QueueItem, series bool) map[int]dlInfo {
+	out := map[int]dlInfo{}
+	for _, q := range items {
+		id := q.MovieID
+		if series {
+			id = q.SeriesID
+		}
+		if id == 0 {
+			continue
+		}
+		d, seen := out[id]
+		d.count++
+		if !seen {
+			d.progress, d.timeLeft = q.Progress(), q.TimeLeft
+		}
+		out[id] = d
+	}
+	return out
+}
+
+// loadQueue fetches both download queues and marks the titles in them.
+// Failures (a service down or not configured) leave the marks as they were.
+func (v *libraryView) loadQueue() {
+	go func() {
+		ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
+		defer cancel()
+		movies, merr := v.radarr.Queue(ctx)
+		series, serr := v.sonarr.Queue(ctx)
+		v.app.post(func() {
+			if merr == nil {
+				v.downloading[kindMovies] = queueByTitle(movies, false)
+			}
+			if serr == nil {
+				v.downloading[kindSeries] = queueByTitle(series, true)
+			}
+			if merr == nil || serr == nil {
+				v.render()
+			}
+		})
+	}()
+}
+
+// startQueueWatch refreshes the queue marks while the Library is visible.
+func (v *libraryView) startQueueWatch() {
+	v.loadQueue()
+	if v.queueStop != nil {
+		return
+	}
+	stop := make(chan struct{})
+	v.queueStop = stop
+	go func() {
+		t := time.NewTicker(libQueueInterval)
+		defer t.Stop()
+		for {
+			select {
+			case <-stop:
+				return
+			case <-t.C:
+				v.app.post(v.loadQueue)
+			}
+		}
+	}()
+}
+
+// deactivate stops the queue watch when the Library is left.
+func (v *libraryView) deactivate() {
+	if v.queueStop != nil {
+		close(v.queueStop)
+		v.queueStop = nil
+	}
+}