Method loadBookConfig

js/ReadingSystem.js:165–196

* 加载课本配置（book.json） * @returns {Promise }

()

   * @returns {Promise<void>}
   */
  async loadBookConfig() {
    if (!this.state.bookPath) {
      this.renderEmptyState(this.config.ERROR_MESSAGES.NO_DATA);
      return;
    }

    try {
      const response = await fetch(`${this.state.bookPath}/book.json`);
      const data = await response.json();

      this.state.units = data.units.map((unit, index) => ({
        ...unit,
        id: index + 1,
        title: unit.title,
        audio: `${this.state.bookPath}/${unit.filename}.mp3`,
        lrc: `${this.state.bookPath}/${unit.filename}.lrc`,
      }));

      if (this.dom.bookCover && data.bookCover) {
        this.dom.bookCover.src = `${this.state.bookPath}/${data.bookCover}`;
      }

      // 清除缓存
      this.lrcCache.clear();
      this.audioPreload.clear();
    } catch (error) {
      console.error(this.config.ERROR_MESSAGES.LOAD_CONFIG, error);
      this.renderEmptyState(
        `${this.config.ERROR_MESSAGES.LOAD_CONFIG}: ${this.state.bookPath}/book.json`
      );
    }
  }

  /**
   * 更新所有课本选择器