/**
 * 查询类命令示例 - 不需要撤销
 */
export class GetCanvasInfoCommand {
  constructor(options) {
    this.canvas = options.canvas;
    this.layerManager = options.layerManager;
    this.undoable = false; // 明确标记为不可撤销
  }

  execute() {
    return {
      width: this.canvas.getWidth(),
      height: this.canvas.getHeight(),
      zoom: this.canvas.getZoom(),
      layers: this.layerManager?.getLayers()?.length || 0,
      objects: this.canvas.getObjects().length,
    };
  }

  // 查询类命令不需要实现 undo 方法
}

/**
 * 导出类命令示例 - 不需要撤销
 */
export class ExportCanvasCommand {
  constructor(options) {
    this.canvas = options.canvas;
    this.format = options.format || "png";
    this.quality = options.quality || 1;
    this.undoable = false;
  }

  execute() {
    return this.canvas.toDataURL(`image/${this.format}`, this.quality);
  }
}

/**
 * 验证类命令示例 - 不需要撤销
 */
export class ValidateCanvasCommand {
  constructor(options) {
    this.canvas = options.canvas;
    this.undoable = false;
  }

  execute() {
    const objects = this.canvas.getObjects();
    const errors = [];

    objects.forEach((obj, index) => {
      if (!obj.left || !obj.top) {
        errors.push(`对象 ${index} 位置无效`);
      }
      if (obj.width <= 0 || obj.height <= 0) {
        errors.push(`对象 ${index} 尺寸无效`);
      }
    });

    return {
      isValid: errors.length === 0,
      errors,
      objectCount: objects.length,
    };
  }
}

/**
 * 系统清理命令示例 - 不可逆操作，不需要撤销
 */
export class CleanupTempDataCommand {
  constructor(options) {
    this.canvas = options.canvas;
    this.undoable = false;
  }

  execute() {
    // 清理临时数据
    const cleaned = [];

    // 移除无效对象
    const objects = this.canvas.getObjects();
    objects.forEach((obj, index) => {
      if (obj._isTemp || obj._invalid) {
        this.canvas.remove(obj);
        cleaned.push(`临时对象 ${index}`);
      }
    });

    // 清理缓存
    if (this.canvas._clearCache) {
      this.canvas._clearCache();
      cleaned.push("画布缓存");
    }

    return {
      cleaned,
      count: cleaned.length,
    };
  }
}