Add music player

src/lib/music/player.svelte.ts

@@ -0,0 +1,137 @@
+import type { Track } from './types';
+import { pickRandomIndex } from './playlist';
+
+class MusicPlayer {
+	tracks = $state<Track[]>([]);
+	currentIndex = $state(-1);
+	startOffset = $state(0);
+	streamKey = $state(0);
+	elapsedSinceStart = $state(0);
+	paused = $state(true);
+	muted = $state(true);
+	volume = $state(0.6);
+	unavailable = $state(false);
+	history = $state<number[]>([]);
+	repeat = $state(false);
+
+	private failedTrackCount = 0;
+	private loading = false;
+
+	get currentTrack(): Track | undefined {
+		return this.tracks[this.currentIndex];
+	}
+
+	get streamUrl(): string {
+		const track = this.currentTrack;
+		if (!track) return '';
+		return this.startOffset > 0 ? `/api/music/${track.id}?start=${this.startOffset}` : `/api/music/${track.id}`;
+	}
+
+	get position(): number {
+		return this.startOffset + this.elapsedSinceStart;
+	}
+
+	get duration(): number {
+		return this.currentTrack?.durationSeconds ?? 0;
+	}
+
+	get canGoBack(): boolean {
+		return this.history.length > 0;
+	}
+
+	async start() {
+		if (this.loading || this.tracks.length > 0) return;
+		this.loading = true;
+		try {
+			const response = await fetch('/api/music');
+			if (response.ok) this.tracks = await response.json();
+		} catch {
+			this.tracks = [];
+		}
+		this.loading = false;
+		if (this.tracks.length > 0) this.changeTrack(pickRandomIndex(this.tracks.length, -1));
+	}
+
+	private changeTrack(index: number) {
+		this.currentIndex = index;
+		this.startOffset = 0;
+		this.elapsedSinceStart = 0;
+		this.streamKey += 1;
+	}
+
+	playTrack(index: number) {
+		if (index !== this.currentIndex) this.history.push(this.currentIndex);
+		this.changeTrack(index);
+		this.paused = false;
+	}
+
+	playRandom() {
+		this.playTrack(pickRandomIndex(this.tracks.length, this.currentIndex));
+	}
+
+	handleEnded() {
+		if (this.repeat) {
+			this.seek(0);
+			return;
+		}
+		this.playRandom();
+	}
+
+	toggleRepeat() {
+		this.repeat = !this.repeat;
+	}
+
+	skipBy(seconds: number) {
+		this.seek(this.position + seconds);
+	}
+
+	playPrevious() {
+		const previousIndex = this.history.pop();
+		if (previousIndex === undefined) return;
+		this.changeTrack(previousIndex);
+		this.paused = false;
+	}
+
+	togglePlay() {
+		this.paused = !this.paused;
+	}
+
+	toggleMute() {
+		this.muted = !this.muted;
+		if (!this.muted) this.paused = false;
+	}
+
+	setVolume(volume: number) {
+		this.volume = volume;
+		this.muted = volume === 0;
+		if (!this.muted) this.paused = false;
+	}
+
+	seek(seconds: number) {
+		this.startOffset = Math.max(0, Math.min(Math.floor(seconds), this.duration - 1));
+		this.elapsedSinceStart = 0;
+		this.streamKey += 1;
+		this.paused = false;
+	}
+
+	handleTimeUpdate(elapsedSeconds: number) {
+		this.elapsedSinceStart = elapsedSeconds;
+	}
+
+	handleTrackLoaded() {
+		this.failedTrackCount = 0;
+	}
+
+	handleTrackError(mediaError: MediaError | null) {
+		console.error(`Music stream failed for ${this.currentTrack?.id}:`, mediaError?.message || mediaError?.code);
+		this.failedTrackCount += 1;
+		if (this.failedTrackCount >= this.tracks.length) {
+			this.unavailable = true;
+			this.paused = true;
+			return;
+		}
+		this.playRandom();
+	}
+}
+
+export const musicPlayer = new MusicPlayer();