/**
 * @(#)2019/11/14.
 * 封装底层请求，试图替代jq的请求
 * @author 足道
 * Copyright (c) 2019, YUNXI. All rights reserved.
 * YUNXI PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

 const jsonpParse = JSON.parse
 class XHR {
   constructor(url, headers, method) {
     this.url = url
     this.method = method
     this.headers = headers || {}
     this.xhr = new XMLHttpRequest()
     this.init()
   }
 
   /**
    * 这样就可以链式调用节约一行代码
    *
    * @static
    * @param {*} url
    * @param {*} header
    * @returns
    * @memberof XHR
    */
   static new(url, header) {
     return new this(url, header)
   }
 
   /**
    * 父类初始化
    *
    * @memberof XHR
    */
   init() {
     this.xhr.timeout = 8000
     this.xhr.open(this.method, this.url, true)
     Object.keys(this.headers).forEach((key) => {
       const val = this.headers[key]
       this.xhr.setRequestHeader(key, val)
     })
   }
 
   _send = (xhr, data) => {
     if (data == null) {
       xhr.send()
     } else {
       xhr.send(data)
     }
   }
 
   /**
    * 请求发送
    *
    * @param {Object} data
    * @returns
    */
   xhrSend(data, onprogress) {
     const { xhr } = this
     xhr.withCredentials = false
     return new Promise((resolve, reject) => {
       xhr.onreadystatechange = (event) => {
         const that = event.currentTarget
         const { status } = that
         if (that.readyState === 4) {
           if ([200, 204].includes(status)) {
             const { response } = that
             resolve(response.data)
           } else if (status === 403) {
             resolve({ status, message: '没有权限' })
           } else if (that.readyState === 4) {
             reject({ status, body: that })
           }
         }
       }
       xhr.onprogress = onprogress
       xhr.ontimeout = () => reject('请求超时')
       xhr.onerror = reject
       this._send(xhr, data)
     })
   }
 }
 
 class PostXhr extends XHR {
   constructor(url, headers) {
     super(url, headers, 'post')
     this.xhr.timeout = 100 * 1000
   }
 
   send(data) {
     this.xhrSend(data)
   }
 }
 
 class GetXhr extends XHR {
   constructor(url, headers) {
     super(url, headers, 'get')
     this.xhr.timeout = 100 * 1000
     this.xhr.responseType = 'json'
   }
 
   send(data) {
     return this.xhrSend(data)
   }
 }
 
 export { PostXhr, GetXhr }