import React from 'react';
import { Play, HardDriveDownload, Trash2 } from 'lucide-react';
import { useTranslation } from 'react-i18next';
import { useOfflineStore } from '../store/offlineStore';
import { useAuthStore } from '../store/authStore';
import { usePlayerStore } from '../store/playerStore';
import { buildCoverArtUrl, coverArtCacheKey } from '../api/subsonic';
import CachedImage from '../components/CachedImage';

export default function OfflineLibrary() {
  const { t } = useTranslation();
  const serverId = useAuthStore(s => s.activeServerId ?? '');
  const offlineAlbums = useOfflineStore(s => s.albums);
  const offlineTracks = useOfflineStore(s => s.tracks);
  const deleteAlbum = useOfflineStore(s => s.deleteAlbum);
  const playTrack = usePlayerStore(s => s.playTrack);
  const enqueue = usePlayerStore(s => s.enqueue);

  const albums = Object.values(offlineAlbums).filter(a => a.serverId === serverId);

const buildTracks = (albumId: string) => {
     const meta = offlineAlbums[`${serverId}:${albumId}`];
     if (!meta) return [];
     return meta.trackIds.flatMap(tid => {
       const t = offlineTracks[`${serverId}:${tid}`];
       if (!t) return [];
       return [{
         id: t.id, title: t.title, artist: t.artist, album: t.album,
         albumId: t.albumId, artistId: t.artistId, duration: t.duration,
         coverArt: t.coverArt, track: undefined, year: t.year,
         bitRate: t.bitRate, suffix: t.suffix, genre: t.genre,
         replayGainTrackDb: t.replayGainTrackDb,
         replayGainAlbumDb: t.replayGainAlbumDb,
         replayGainPeak: t.replayGainPeak,
       }];
     });
   };

  const handlePlay = (albumId: string) => {
    const tracks = buildTracks(albumId);
    if (tracks[0]) playTrack(tracks[0], tracks);
  };

  const handleEnqueue = (albumId: string) => {
    enqueue(buildTracks(albumId));
  };

  return (
    <div className="offline-library animate-fade-in">
      <div className="offline-library-header">
        <HardDriveDownload size={24} />
        <div>
          <h1 className="offline-library-title">{t('connection.offlineLibraryTitle')}</h1>
          <p className="offline-library-count">
            {t('connection.offlineAlbumCount', { n: albums.length, count: albums.length })}
          </p>
        </div>
      </div>

      {albums.length === 0 ? (
        <div className="empty-state">{t('connection.offlineLibraryEmpty')}</div>
      ) : (
        <div className="album-grid-wrap">
          {albums.map(album => {
            const coverUrl = album.coverArt ? buildCoverArtUrl(album.coverArt, 300) : '';
            const cacheKey = album.coverArt ? coverArtCacheKey(album.coverArt, 300) : '';
            const trackCount = album.trackIds.filter(tid => !!offlineTracks[`${serverId}:${tid}`]).length;
            return (
              <div key={album.id} className="album-card card offline-library-card">
                <div className="album-card-cover">
                  {coverUrl ? (
                    <CachedImage src={coverUrl} cacheKey={cacheKey} alt={`${album.name} Cover`} loading="lazy" />
                  ) : (
                    <div className="album-card-cover-placeholder">
                      <HardDriveDownload size={32} />
                    </div>
                  )}
                  <div className="album-card-play-overlay">
                    <button
                      className="album-card-details-btn"
                      onClick={() => handlePlay(album.id)}
                      aria-label={`${album.name} abspielen`}
                    >
                      <Play size={15} fill="currentColor" />
                    </button>
                  </div>
                </div>
                <div className="album-card-info">
                  <p className="album-card-title truncate">{album.name}</p>
                  <p className="album-card-artist truncate">{album.artist}</p>
                  {album.year && <p className="album-card-year">{album.year}</p>}
                  <div className="offline-library-card-meta">
                    <button
                      className="offline-library-enqueue"
                      onClick={() => handleEnqueue(album.id)}
                      title="Zur Warteschlange hinzufügen"
                    >
                      + Queue
                    </button>
                    <span className="offline-library-tracks">{trackCount} tracks</span>
                    <button
                      className="offline-library-delete"
                      onClick={() => deleteAlbum(album.id, serverId)}
                      data-tooltip={t('albumDetail.removeOffline')}
                      data-tooltip-pos="top"
                    >
                      <Trash2 size={11} />
                    </button>
                  </div>
                </div>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
}