feat: filter yt-dlp results by song duration to avoid wrong downloads

When iTunes/Spotify provides a track duration, search 5 YouTube results
and keep only those within 60–150% of the expected length (filters remixes,
prayer videos, etc.). Falls back to ytsearch1: if no match is found.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/novasonic-server.js

@@ -156,12 +156,13 @@ async function lookupItunesTrackMeta(artist, title) {
       discTotal:   match.discCount     || undefined,
       genre:       match.primaryGenreName || undefined,
       artworkUrl:  (match.artworkUrl100 || '').replace('100x100bb', '1000x1000bb'),
+      durationMs:  match.trackTimeMillis  || undefined,
     };
   } catch { return {}; }
 }
 
 // Download a single track: yt-dlp audio + ffmpeg clean metadata + iTunes cover embedded
-async function downloadTrack({ jobId, artist, albumArtist, title, album, year, trackNum, totalTracks, discNum, discTotal, compilation, genre, artworkUrl, explicit, outputDir }) {
+async function downloadTrack({ jobId, artist, albumArtist, title, album, year, trackNum, totalTracks, discNum, discTotal, compilation, genre, artworkUrl, explicit, outputDir, durationMs }) {
   const mainArtist = albumArtist || artist;
   const safeArtist = sanitize(mainArtist.split(',')[0].trim());
   const safeAlbum  = sanitize(album || 'Singles');
@@ -179,21 +180,20 @@ async function downloadTrack({ jobId, artist, albumArtist, title, album, year, t
 
   const outputTemplate = path.join(dir, `${trackPrefix}${safeTitle}.%(ext)s`);
   const query          = `${mainArtist} - ${title} official audio`;
-  log(jobId, `🔍 Suche: "${query}"`);
 
   // Step 1: yt-dlp — audio only, no thumbnail (we embed iTunes artwork ourselves)
-  await new Promise((resolve, reject) => {
-    const args = [
-      `ytsearch1:${query}`,
-      '--extract-audio',
-      '--audio-format',   CONFIG.audioFmt,
-      '--audio-quality',  CONFIG.audioQuality,
-      '-o',               outputTemplate,
-      '--no-playlist',
-      '--playlist-items', '1',
-      '--no-warnings',
-      '--newline',
-    ];
+  const baseArgs = [
+    '--extract-audio',
+    '--audio-format',   CONFIG.audioFmt,
+    '--audio-quality',  CONFIG.audioQuality,
+    '-o',               outputTemplate,
+    '--no-playlist',
+    '--playlist-items', '1',
+    '--no-warnings',
+    '--newline',
+  ];
+
+  const spawnYtdlp = (args) => new Promise((resolve, reject) => {
     const proc = spawn(CONFIG.ytdlpBin, args, { env: { ...process.env, PYTHONUNBUFFERED: '1' } });
     let stderr = '', lastPct = '';
     proc.stdout.on('data', d => {
@@ -215,6 +215,28 @@ async function downloadTrack({ jobId, artist, albumArtist, title, album, year, t
     );
   });
 
+  if (durationMs) {
+    const durationSec = Math.round(durationMs / 1000);
+    const minDur = Math.max(30, Math.round(durationSec * 0.6));
+    const maxDur = Math.round(durationSec * 1.5);
+    log(jobId, `🔍 Suche (~${durationSec}s): "${query}"`);
+    await spawnYtdlp([
+      `ytsearch5:${query}`,
+      '--match-filter', `duration > ${minDur} & duration < ${maxDur} & !is_live`,
+      '--max-downloads', '1',
+      ...baseArgs,
+    ]);
+    // Fallback if duration filter matched nothing
+    const hasFile = fs.readdirSync(dir).some(f => AUDIO_EXTS.some(e => f.endsWith(`.${e}`)));
+    if (!hasFile) {
+      log(jobId, '⚠️  Kein Treffer im Dauerbereich — Suche ohne Filter…');
+      await spawnYtdlp([`ytsearch1:${query}`, ...baseArgs]);
+    }
+  } else {
+    log(jobId, `🔍 Suche: "${query}"`);
+    await spawnYtdlp([`ytsearch1:${query}`, ...baseArgs]);
+  }
+
   // Step 2: find the audio file yt-dlp wrote (newest audio file in dir)
   const audioFile = fs.readdirSync(dir)
     .filter(f => AUDIO_EXTS.some(e => f.endsWith(`.${e}`)))
@@ -323,6 +345,7 @@ async function downloadAlbumTracks({ jobId, artist, albumTitle, tracks, artworkU
         artworkUrl:  artworkUrl || track.artworkUrl100,
         explicit:    track.trackExplicitness === 'explicit',
         outputDir:   CONFIG.musicPath,
+        durationMs:  track.trackTimeMillis || undefined,
       });
       if (result?.skipped) skipped++; else done++;
       updateJob(jobId, { progress: Math.round(((done + skipped) / total) * 90) });
@@ -480,6 +503,7 @@ function _spTrackItem(t, defaultAlbum, defaultArt, defaultAlbumArtist) {
     trackNumber:       d?.trackNumber || d?.track_number,
     trackExplicitness: d?.contentRating?.label === 'EXPLICIT' || d?.isExplicit || d?.explicit ? 'explicit' : 'notExplicit',
     previewUrl:        d?.previewUrl || d?.preview_url || d?.audioPreview?.url || null,
+    durationMs:        d?.duration_ms || d?.durationMs || null,
   };
 }
 
@@ -590,7 +614,8 @@ app.post('/api/download', async (req, res) => {
           totalTracks: sp.trackCount   || bodyTotalTracks || undefined,
           discNum:     sp.discNumber   || bodyDiscNum     || undefined,
           discTotal:   sp.discCount    || bodyDiscTotal   || undefined,
-          artworkUrl: spArt, explicit: sp.trackExplicitness === 'explicit' || !!explicit };
+          artworkUrl: spArt, explicit: sp.trackExplicitness === 'explicit' || !!explicit,
+          durationMs: sp.durationMs || undefined };
         if (!meta.album) {
           // Use first artist only for iTunes search (multi-artist strings like "Kløn, Renzyx" confuse iTunes)
           const searchArtist = artist.split(',')[0].trim();
@@ -679,6 +704,7 @@ app.post('/api/download', async (req, res) => {
               genre:       itunes.genre      || track.primaryGenreName || undefined,
               artworkUrl:  itunes.artworkUrl || track.artworkUrl100 || '',
               explicit:    track.trackExplicitness === 'explicit',
+              durationMs:  itunes.durationMs || track.durationMs   || undefined,
             });
             if (result?.skipped) skipped++; else done++;
             updateJob(jobId, { progress: Math.round(((done + skipped) / plTracks.length) * 90) });

src/ui.js

@@ -294,10 +294,11 @@ export async function executeDownload() {
     itunesId:    S.downloadTarget.trackId || S.downloadTarget.collectionId || null,
     collectionId: S.downloadTarget.collectionId || null,
     explicit:    S.downloadTarget.trackExplicitness === 'explicit',
-    trackNum:    S.downloadTarget.trackNumber  || undefined,
-    totalTracks: S.downloadTarget.trackCount   || undefined,
-    discNum:     S.downloadTarget.discNumber   || undefined,
-    discTotal:   S.downloadTarget.discCount    || undefined,
+    trackNum:    S.downloadTarget.trackNumber    || undefined,
+    totalTracks: S.downloadTarget.trackCount     || undefined,
+    discNum:     S.downloadTarget.discNumber     || undefined,
+    discTotal:   S.downloadTarget.discCount      || undefined,
+    durationMs:  S.downloadTarget.trackTimeMillis || undefined,
   };
   addJob(jobId, payload.title, payload.artist, payload.type);
   try {