import { http } from '@kit.NetworkKit';

const TAG = 'httpRequestInStream'
export class httpRequest {
  // 大于5M的下载请求，使用流下载
  /**
   * 发起HTTP请求以下载图片资源
   * @param {string} imageUrl 图片的URL
   * @param {Function} onSuccess 成功回调函数
   * @param {Function} onError 失败回调函数
   */
  public static httpRequestInStream(imageUrl:string, onSuccess:Function, onError:Function) {
    // 每一个httpRequest对应一个HTTP请求任务，不可复用
    const httpRequest = http.createHttp();

    // 订阅HTTP响应头事件
    httpRequest.on('headersReceive', (header) => {
      // console.info('header: ' + JSON.stringify(header));
    });

    // 用于订阅HTTP流式响应数据接收事件
    let res = new ArrayBuffer(0);

    httpRequest.on('dataReceive', (data) => {
      const newRes = new ArrayBuffer(res.byteLength + data.byteLength);
      const resView = new Uint8Array(newRes);
      resView.set(new Uint8Array(res));
      resView.set(new Uint8Array(data), res.byteLength);
      res = newRes;
      // console.info(TAG, 'dataReceive res length: ' + res.byteLength);
    });

    // 用于订阅HTTP流式响应数据接收完毕事件
    httpRequest.on('dataEnd', () => {
      if (res instanceof ArrayBuffer) {
        // 如果成功，调用onSuccess回调
        // console.info(TAG, 'Success in response, data receive end');
        onSuccess(res);
      } else {
        // 如果数据不是ArrayBuffer类型，可以在这里处理异常
        // console.error(TAG, 'Unexpected data type:', res);
        onError(new Error('Data is not an ArrayBuffer'));
      }
      // console.info(TAG, 'No more data in response, data receive end');
    });

    httpRequest.requestInStream(imageUrl, (error, data) => {
      if (error) {
        // 如果发生错误，取消订阅事件并销毁请求对象
        httpRequest.off('headersReceive');
        httpRequest.off('dataReceive');
        httpRequest.off('dataEnd');
        httpRequest.destroy();
        // console.error(`http request failed with. Code: ${error.code}, message: ${error.message}`);
        // 调用onError回调
        onError(error);
        return;
      }

      // 取消订阅事件
      httpRequest.off('headersReceive');
      httpRequest.off('dataReceive');
      httpRequest.off('dataEnd');

      // 销毁请求对象
      httpRequest.destroy();
    });
  }
}