const CONFIG       = require('./config');
const { log, updateJob } = require('./jobs');
const ytdlp        = require('./ytdlp');
const squid        = require('./squid');

// Route a single track download to the correct backend, with optional fallback.
async function downloadTrack(opts) {
  const backend = CONFIG.downloadBackend;

  if (backend === 'ytdlp') return ytdlp.downloadTrack(opts);
  if (backend === 'squid') return squid.downloadTrack(opts);

  // 'auto': squid first, yt-dlp as fallback
  try {
    const result = await squid.downloadTrack(opts);
    if (result !== null) return result;
    // null = not found on Qobuz — fall through to yt-dlp
    log(opts.jobId, '⚠️  squid.wtf: nicht gefunden — Fallback zu yt-dlp');
  } catch (e) {
    log(opts.jobId, `⚠️  squid.wtf Fehler — Fallback zu yt-dlp: ${e.message}`);
  }
  return ytdlp.downloadTrack(opts);
}

// Download all tracks of an album sequentially, updating job progress.
async function downloadAlbumTracks({ jobId, artist, albumTitle, tracks, artworkUrl }) {
  const total = tracks.length;
  log(jobId, `📀 Album "${albumTitle}" — ${total} Tracks`);
  let done = 0, skipped = 0;

  for (const track of tracks) {
    try {
      const result = await downloadTrack({
        jobId,
        artist:      track.artistName   || artist,
        albumArtist: artist,
        title:       track.trackName    || track.title,
        album:       albumTitle,
        year:        track.releaseDate  ? new Date(track.releaseDate).getFullYear() : undefined,
        trackNum:    track.trackNumber  || undefined,
        totalTracks: total,
        discNum:     track.discNumber   || undefined,
        discTotal:   track.discCount    || undefined,
        compilation: track.collectionType === 'Compilation' || undefined,
        genre:       track.primaryGenreName || undefined,
        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) });
    } catch (e) {
      log(jobId, `⚠️  Fehler bei "${track.trackName || track.title}": ${e.message}`);
    }
  }
  return { done, skipped };
}

module.exports = { downloadTrack, downloadAlbumTracks };