/**
 * 앨범 서비스
 * 앨범 관련 비즈니스 로직
 */

/**
 * 앨범 상세 정보 조회 (트랙, 티저, 컨셉포토 포함)
 * @param {object} db - 데이터베이스 연결
 * @param {object} album - 앨범 기본 정보
 * @returns {object} 상세 정보가 포함된 앨범
 */
export async function getAlbumDetails(db, album) {
  const [tracks] = await db.query(
    'SELECT * FROM album_tracks WHERE album_id = ? ORDER BY track_number',
    [album.id]
  );
  album.tracks = tracks;

  const [teasers] = await db.query(
    `SELECT original_url, medium_url, thumb_url, video_url, media_type
     FROM album_teasers WHERE album_id = ? ORDER BY sort_order`,
    [album.id]
  );
  album.teasers = teasers;

  const [photos] = await db.query(
    `SELECT
      p.id, p.original_url, p.medium_url, p.thumb_url, p.photo_type, p.concept_name, p.sort_order,
      p.width, p.height,
      GROUP_CONCAT(m.name ORDER BY m.id SEPARATOR ', ') as members
    FROM album_photos p
    LEFT JOIN album_photo_members pm ON p.id = pm.photo_id
    LEFT JOIN members m ON pm.member_id = m.id
    WHERE p.album_id = ?
    GROUP BY p.id
    ORDER BY p.sort_order`,
    [album.id]
  );

  const conceptPhotos = {};
  for (const photo of photos) {
    const concept = photo.concept_name || 'Default';
    if (!conceptPhotos[concept]) {
      conceptPhotos[concept] = [];
    }
    conceptPhotos[concept].push({
      id: photo.id,
      original_url: photo.original_url,
      medium_url: photo.medium_url,
      thumb_url: photo.thumb_url,
      width: photo.width,
      height: photo.height,
      type: photo.photo_type,
      members: photo.members,
      sortOrder: photo.sort_order,
    });
  }
  album.conceptPhotos = conceptPhotos;

  return album;
}

/**
 * 앨범 목록과 트랙 조회 (N+1 최적화)
 * @param {object} db - 데이터베이스 연결
 * @returns {array} 트랙 포함된 앨범 목록
 */
export async function getAlbumsWithTracks(db) {
  const [albums] = await db.query(`
    SELECT id, title, folder_name, album_type, album_type_short, release_date,
           cover_original_url, cover_medium_url, cover_thumb_url, description
    FROM albums
    ORDER BY release_date DESC
  `);

  if (albums.length === 0) return albums;

  // 모든 트랙을 한 번에 조회
  const albumIds = albums.map(a => a.id);
  const [allTracks] = await db.query(
    `SELECT id, album_id, track_number, title, is_title_track, duration, lyricist, composer, arranger
     FROM album_tracks WHERE album_id IN (?) ORDER BY album_id, track_number`,
    [albumIds]
  );

  // 앨범 ID별로 트랙 그룹화
  const tracksByAlbum = {};
  for (const track of allTracks) {
    if (!tracksByAlbum[track.album_id]) {
      tracksByAlbum[track.album_id] = [];
    }
    tracksByAlbum[track.album_id].push(track);
  }

  // 각 앨범에 트랙 할당
  for (const album of albums) {
    album.tracks = tracksByAlbum[album.id] || [];
  }

  return albums;
}