import axios from 'axios'

export class AjaxError extends Error {
  code = 0

  constructor (msg, code) {
    super(msg || '未知错误')
    this.code = code
  }
}

const CancelToken = axios.CancelToken

const link = document.createElement('a')

// const RESPONSE_ERROR = 'ResponseError'
const REQUEST_CANCEL = 'RequestCancel'

const request = axios.create({
  baseURL: process.env.API_BASE_PATH,
  timeout: 300000
})

request.interceptors.request.use(config => {
  return config
}, error => new Promise((resolve, reject) => reject(error)))

request.interceptors.response.use(response => new Promise((resolve, reject) => {
  const { config, data } = response
  if (/^(blob)$/i.test(config.responseType)) {
    if (data instanceof Blob) {
      const match = /filename=([^;]+)/.exec(response.headers['content-disposition'])
      if (match) {
        let filename = decodeURIComponent(match).split(',')
        link.href = URL.createObjectURL(data)
        link.download = filename ? filename[filename.length - 1] : ''
        link.click()
        URL.revokeObjectURL(link.href)
      }
      return resolve(response)
    }

    return resolve(data)
  }

  if (typeof data !== 'object' || data === null) {
    return reject(new AjaxError('数据格式不正确', 30000))
  }

  const { type } = data
  if (type === 'success') {
    return resolve(data.data)
  }

  return reject(new AjaxError(data.msg, 500))
}), error => {
  if (error.message === REQUEST_CANCEL) {
    return
  }

  if (!(error instanceof AjaxError)) {
    error = new AjaxError('服务器正忙', 500)
  }

  return Promise.reject(error)
})

export const api = (config) => {
  const source = CancelToken.source()
  config = Object.assign({ cancelToken: source.token }, config)
  const promise = request(config)
  promise.abort = () => source.cancel(REQUEST_CANCEL)
  return promise
}