import axios from 'axios'
import { getToken } from '@/utils/auth'
import { Loading, Message } from 'element-ui'

/*
 * @params {string} url 请求拼接地址
 * @params {object} info 请求参数params或data
 */

let loading;
export async function download(url,method='get',info,filename){

  loading = Loading.service({
    lock:true,
    background:"rgba(0,0,0,0.4)",
    text:"文件正在生成中..."
  })

  let options = {
    baseURL:process.env.VUE_APP_BASE_API,
    url,
    method,
    responseType: 'blob',
    timeout:10000,
    headers: {
      Accept: 'application/json','Content-Type':'application/json; charset=utf-8',
      withCredentials: true,
      Authorization:"Bearer " + getToken()
    },
  }
  if(method === 'get'){
    Object.defineProperty(options,'params',{
      value:info,
      enumerable:true,
      writable:false
    })
  }
  if(method === 'post'){
    Object.defineProperty(options,'data',{
      value:info,
      enumerable:true,
      writable:false
    })
  }

  try {
    const response = await axios.request(options)

    loading.close()

    // 提取文件名
    if(!filename){
      filename = response.headers['content-disposition']?.match(
        /filename=(.*)/
      )[1] || ''
    }

    // 将二进制流转为blob
    const blob = new Blob([response.data], { type: 'application/octet-stream' })
    if (typeof window.navigator.msSaveBlob !== 'undefined') {
      // 兼容IE，window.navigator.msSaveBlob：以本地方式保存文件
      window.navigator.msSaveBlob(blob, decodeURI(filename))
    } else {
      // 创建新的URL并指向File对象或者Blob对象的地址
      const blobURL = window.URL.createObjectURL(blob)
      // 创建a标签，用于跳转至下载链接
      const tempLink = document.createElement('a')
      tempLink.style.display = 'none'
      tempLink.href = blobURL
      tempLink.setAttribute('download', decodeURI(filename))
      // 兼容：某些浏览器不支持HTML5的download属性
      if (typeof tempLink.download === 'undefined') {
        tempLink.setAttribute('target', '_blank')
      }
      // 挂载a标签
      document.body.appendChild(tempLink)
      tempLink.click()
      document.body.removeChild(tempLink)
      // 释放blob URL地址
      window.URL.revokeObjectURL(blobURL)
    }
  }catch (err){
    console.error(err)
    loading.close()
    Message({
      type:'error',
      message:err
    })
  }
}