//位置为 /util/downloadSaveFile.js
 
/**
 * 下载单个文件
 * @param {string} [type]
 * @param {string} url
 * @callback successCallback
 * @callback failCallback
 */
function downloadFile(type, url, successc, failc) {
    checkAuth(() => {
      wx.showLoading({
        title: '正在下载',
        mask: true
      })
      downloadSaveFile(
        type,
        url,
        () => {
          wx.hideLoading();
          wx.showToast({
            title: '下载成功',
            icon: 'none',
          })
          successc && successc();
        },
        (errMsg) => {
          wx.hideLoading();
          wx.showToast({
            title: errMsg,
            icon: 'none',
          })
          failc && failc();
        }
      );
    })
  }
   
  /**
   * 下载多个文件
   * @param {string} [type]
   * @param {string[]} urls
   * @callback completeCallback
   */
  function downloadFiles(type, urls, completec) {
    let success = 0;
    let fail = 0;
    let total = urls.length;
    let errMsgs = [];
   
    checkAuth(() => {
      wx.showLoading({
        title: '正在下载',
        mask: true
      })
      for (let i = 0; i < urls.length; i++) {
        downloadSaveFile(
          type,
          urls[i],
          () => {
            success++;
            if (success + fail === total) {
              saveCompleted(success, fail, completec, errMsgs);
            }
          },
          (errMsg) => {
            fail++;
            errMsg && errMsgs.push(`视频${i}${errMsg}`);
            if (success + fail === total) {
              saveCompleted(success, fail, completec, errMsgs);
            }
          }
        );
      }
    })
  }
   
  //保存完成
  function saveCompleted(success, fail, completec, errMsgs) {
    wx.hideLoading();
    let errMsg = '无';
    if (errMsgs.length) {
      errMsg = errMsgs.join('\n');
    }
   
    wx.showModal({
      title: `成功${success}项，失败${fail}项`,
      content: `失败信息:\n${errMsg}`,
      showCancel: false,
      success(res) {
        if (res.confirm) {
          completec && completec();
        }
      }
    })
  }
   
  //下载文件
  function downloadSaveFile(type, url, successc, failc) {
    wx.downloadFile({
      url: url,
      success: res => {
        if (res.statusCode === 200) {
          if (type === 'video') {
            //类型为视频
            wx.saveVideoToPhotosAlbum({
              filePath: res.tempFilePath,
              success: res => {
                successc && successc();
              },
              fail: res => {
                failc && failc('保存失败');
              }
            })
          } else if (type === 'image') {
            //类型为图片
            wx.saveImageToPhotosAlbum({
              filePath: res.tempFilePath,
              success: res => {
                successc && successc();
              },
              fail: res => {
                failc && failc('保存失败');
              }
            })
          }
        } else {
          failc && failc('状态码非200');
        }
      },
      fail: res => {
        failc && failc('下载失败');
      }
    })
  }
   
  //检查权限
  function checkAuth(gotc) {
    //查询权限
    wx.showLoading({
      title: '检查授权情况',
      mask: true
    })
    wx.getSetting({
      success(res) {
        wx.hideLoading();
        if (!res.authSetting['scope.writePhotosAlbum']) {
          //请求授权
          wx.authorize({
            scope: 'scope.writePhotosAlbum',
            success() {
              //获得授权，开始下载
              gotc && gotc();
            },
            fail() {
              wx.showModal({
                title: '',
                content: '保存到系统相册需要授权',
                confirmText: '授权',
                success(res) {
                  if (res.confirm) {
                    wx.openSetting({
                      success(res) {
                        if (res.authSetting['scope.writePhotosAlbum'] === true) {
                          gotc && gotc();
                        }
                      }
                    })
                  }
                },
                fail() {
                  wx.showToast({
                    title: '打开设置页失败',
                    icon: 'none',
                  })
                }
              })
            }
          })
        } else {
          //已有授权
          gotc && gotc();
        }
      },
      fail() {
        wx.hideLoading();
        wx.showToast({
          title: '获取授权失败',
          icon: 'none',
        })
      }
    })
  }
   
  module.exports = {
    downloadFile,
    downloadFiles
  };