Class SongDownloadStrategy

src/core/resource/DownloadManager.ts:52–375

* 歌曲下载策略

 * 歌曲下载策略
 */
class SongDownloadStrategy implements DownloadStrategy {
  private settingStore = useSettingStore();
  private dataStore = useDataStore();

  // prepare 阶段准备的状态
  private _downloadUrl = "";
  private fileType = "mp3";
  private lyricResult: LyricResult | null = null;
  private basicLyric = "";
  private ttmlLyric = "";
  private yrcLyric = "";
  private albumArtists: string[] = [];

  constructor(
    public readonly song: SongType,
    private quality: SongLevelType,
  ) {}

  get id() {
    return this.song.id;
  }
  get name() {
    return this.song.name;
  }
  get downloadUrl() {
    return this._downloadUrl;
  }

  async prepare(): Promise<void> {
    // 解析下载链接
    const { url, type } = await this.resolveUrl();
    this._downloadUrl = url;
    this.fileType = type;

    // 获取歌词
    if (this.shouldDownloadLyrics()) {
      this.lyricResult = (await songLyric(this.song.id)) as LyricResult;

      const options: LyricProcessorOptions = {
        downloadLyricToTraditional: this.settingStore.downloadLyricToTraditional,
        downloadLyricTranslation: this.settingStore.downloadLyricTranslation,
        downloadLyricRomaji: this.settingStore.downloadLyricRomaji,
        downloadLyricEncoding: this.settingStore.downloadLyricEncoding,
      };

      // 处理基础歌词
      this.basicLyric = await LyricProcessor.processBasic(this.lyricResult, options);

      // 处理逐字歌词 (后续使用)
      const { downloadMakeYrc, downloadSaveAsAss } = this.settingStore;
      if (downloadMakeYrc || downloadSaveAsAss) {
        let ttmlLyric = "";
        const yrcLyric = this.lyricResult?.yrc?.lyric || "";
        let qmResultData;

        try {
          const ttmlRes = await songLyricTTML(this.song.id);
          if (typeof ttmlRes === "string") ttmlLyric = ttmlRes;