enh/refac: read aloud audio queue

src/lib/utils/audio.ts

@@ -0,0 +1,73 @@
+export class AudioQueue {
+	constructor(audioElement) {
+		this.audio = audioElement;
+		this.queue = [];
+		this.current = null;
+		this.id = null;
+
+		this._onEnded = () => this.next();
+		this.audio.addEventListener('ended', this._onEnded);
+
+		this.onStopped = null; // optional callback
+	}
+
+	setId(newId) {
+		console.log('Setting audio queue ID to:', newId);
+		if (this.id !== newId) {
+			this.stop();
+			this.id = newId;
+			if (this.onStopped) this.onStopped({ event: 'id-change', id: newId });
+		}
+	}
+
+	setPlaybackRate(rate) {
+		console.log('Setting audio playback rate to:', rate);
+		this.audio.playbackRate = rate;
+	}
+
+	enqueue(url) {
+		console.log('Enqueuing audio URL:', url);
+		this.queue.push(url);
+
+		// Auto-play if nothing is currently playing or loaded
+		if (this.audio.paused && !this.current) {
+			this.next();
+		}
+	}
+
+	play() {
+		if (!this.current && this.queue.length > 0) {
+			this.next();
+		} else {
+			this.audio.play();
+		}
+	}
+
+	next() {
+		this.current = this.queue.shift();
+		if (this.current) {
+			this.audio.src = this.current;
+			this.audio.play();
+			console.log('Playing audio URL:', this.current);
+		} else {
+			this.stop();
+			if (this.onStopped) this.onStopped({ event: 'empty-queue', id: this.id });
+		}
+	}
+
+	stop() {
+		this.audio.pause();
+		this.audio.currentTime = 0;
+		this.audio.src = '';
+		this.queue = [];
+		this.current = null;
+		if (this.onStopped) this.onStopped({ event: 'stop', id: this.id });
+	}
+
+	destroy() {
+		this.audio.removeEventListener('ended', this._onEnded);
+		this.stop();
+		this.onStopped = null;
+		this.audio = null;
+	}
+}