Add music player

src/lib/server/music.ts

@@ -0,0 +1,78 @@
+import { Quality, Ytdl, parseVideoId } from '@distube/ytdl-core';
+import { spawn } from 'node:child_process';
+import { Readable } from 'node:stream';
+import { playlist } from '#lib/content';
+import type { Track } from '#lib/music/types';
+
+const downloadBufferBytes = 32 * 1024 * 1024;
+const mp3Bitrate = '160k';
+
+const youtube = new Ytdl();
+
+const playlistVideoIds = playlist.videos.flatMap((video) => {
+	const videoId = parseVideoId(video);
+	return videoId ? [videoId] : [];
+});
+const allowedVideoIds = new Set(playlistVideoIds);
+const trackCache = new Map<string, Track>();
+
+export function isPlaylistVideo(videoId: string): boolean {
+	return allowedVideoIds.has(videoId);
+}
+
+async function getTrack(videoId: string): Promise<Track> {
+	const cachedTrack = trackCache.get(videoId);
+	if (cachedTrack) return cachedTrack;
+
+	const { videoDetails } = await youtube.getInfo(videoId);
+	const track: Track = {
+		id: videoId,
+		title: videoDetails.title,
+		artist: videoDetails.author.name,
+		durationSeconds: videoDetails.lengthSeconds,
+		cover: `https://i.ytimg.com/vi/${videoId}/hqdefault.jpg`
+	};
+	trackCache.set(videoId, track);
+	return track;
+}
+
+export async function getPlaylistTracks(): Promise<Track[]> {
+	const results = await Promise.allSettled(playlistVideoIds.map(getTrack));
+	return results.flatMap((result, index) => {
+		if (result.status === 'fulfilled') return [result.value];
+		console.error(`Music lookup failed for ${playlistVideoIds[index]}:`, result.reason);
+		return [];
+	});
+}
+
+export function streamTrackAsMp3(videoId: string, startSeconds: number): ReadableStream<Uint8Array> {
+	const downloadController = new AbortController();
+	const youtubeAudio = youtube.download(videoId, {
+		quality: Quality.HighestAudio,
+		filter: { hasAudio: true, hasVideo: false },
+		highWaterMark: downloadBufferBytes,
+		signal: downloadController.signal
+	});
+	const ffmpegArguments = ['-loglevel', 'error', '-ss', String(startSeconds), '-i', 'pipe:0', '-vn', '-f', 'mp3', '-b:a', mp3Bitrate, 'pipe:1'];
+	const ffmpeg = spawn('ffmpeg', ffmpegArguments, { stdio: ['pipe', 'pipe', 'inherit'] });
+
+	const stop = () => {
+		downloadController.abort();
+		youtubeAudio.destroy();
+		if (ffmpeg.exitCode === null) ffmpeg.kill('SIGKILL');
+	};
+
+	youtubeAudio.on('error', (error) => {
+		console.error(`Music download failed for ${videoId}:`, error);
+		stop();
+	});
+	ffmpeg.on('error', (error) => {
+		console.error('ffmpeg failed to start:', error);
+		stop();
+	});
+	ffmpeg.stdin.on('error', stop);
+	ffmpeg.stdout.on('close', stop);
+	youtubeAudio.pipe(ffmpeg.stdin);
+
+	return Readable.toWeb(ffmpeg.stdout) as ReadableStream<Uint8Array>;
+}