class WebSocketClass {
    constructor (wsUrl) {
      this.successFn = {}  // 成功的回掉函数
      this.wsUrl = wsUrl    // 请求的url
      this.errorCallBackFunArr = [] // 当推送异常时执行的数组
      this.isConnection = false // 判断是否支持weosocket
      this.isErrorCallBack = false
      this.lockReconnect = false // 避免重复连接
      this.ping = null
      this.sendObj = {}  
      this.heartCheck()
      this.createWebSocket()
    }
    createWebSocket () {
      try {
        this.webSocket = new WebSocket(this.wsUrl)
        this.initEventHandle()
      } catch (e) {
        this.errorCallBackData()
        this.reconnect(this.wsUrl)
      }
    }
    initEventHandle () {
      this.webSocket.onclose = () => {
        this.errorCallBackData()
        this.reconnect(this.wsUrl)
      }
      this.webSocket.onerror = () => {
        this.errorCallBackData()
        this.reconnect(this.wsUrl)
      }
      this.webSocket.onopen = () => {
        this.isConnection = true
        this.isErrorCallBack = false
        clearInterval(this.ping)
        this.ping = setInterval(() => {
          this.send('{"event": "ping"}')
        }, 10000)
        // 心跳检测重置
        this.heartCheck.start()
      }
      this.webSocket.onmessage = data => {
        // 如果获取到消息，心跳检测重置
        // 拿到任何消息都说明当前连接是正常的
        this.heartCheck.start()
        this.decodeData(data)
      }
    }
    send(cmd) {
      // 只有当  webSocket.readyState 为 OPEN才发送订阅
      // readyState属性返回实例对象的当前状态，共有四种。
      // CONNECTING：值为0，表示正在连接。
      // OPEN：值为1，表示连接成功，可以通信了。
      // CLOSING：值为2，表示连接正在关闭。
      // CLOSED：值为3，表示连接已经关闭，或者打开连接失败。
      if (!cmd) {
        return
      }
      // this.sendObj[cmd] && (delete clearTimeout(this.sendObj[cmd]))
      if (this.webSocket.readyState === 1) { // 只有当链接打开时才进行订阅          
        this.webSocket.send(cmd)
      }
      //  else if (this.webSocket.readyState === 0) { // 如果链接处于正在链接中，则进行延时订阅
      //    this.sendObj[cmd] = setTimeout(() => {
      //       this.send(cmd)
      //   }, 50)
      // }
    }

    reconnect (url) {
      if (this.lockReconnect) {
        return
      }
      this.lockReconnect = true
      // 没连接上会一直重连，设置延迟避免请求过多
      setTimeout(() => {
        this.createWebSocket(url)
        this.lockReconnect = false
      }, 2000)
    }
    errorCallBackData () {
      this.isConnection = false
      if (!this.isErrorCallBack && this.errorCallBackFunArr.length) {
        this.isErrorCallBack = true
        for (let i = 0, len = this.errorCallBackFunArr.length; i < len; i++) {
          if ((typeof this.errorCallBackFunArr[i]) === 'function') {
            this.errorCallBackFunArr[i]()
          }
        }
      }
    }
    decodeData (data) {
      if (data.data instanceof Blob) {
        let blob = data.data
        // js中的blob没有没有直接读出其数据的方法，通过FileReader来读取相关数据
        let reader = new FileReader()
        reader.readAsArrayBuffer(blob)
        // 当读取操作成功完成时调用.
        reader.onload = (evt) => {
          if (evt.target.readyState === FileReader.DONE) {
            let result = new Uint8Array(evt.target.result)
            // 如果后端进行压缩数据处理（zlib），那么要引入解析zlib的js
            result = (new window.Zlib.RawInflate(result)).decompress()
            let strResult = ''
            let length = result.length
            for (let i = 0; i < length; i++) {
              strResult += String.fromCharCode(result[i])
            }
            this.callBackData(JSON.parse(strResult))
          }
        }
        return
      }
      let d = JSON.parse(data.data)
      // 如果后端需要等待，则返回code：10010，过一段时间后重新订阅
      if (d.code === '10010') {
        let dt = {}
        Object.assign(dt, d)
        delete dt.code
        delete dt.msg
        setTimeout(() => {
          this.send(JSON.stringify(dt))
        }, 2000)
        return
      }
      this.callBackData(JSON.parse(data.data))
    }
    callBackData (data) {
      if (data instanceof Array) {
        for (let i = 0; i < data.length; i++) {
          this.doCallback(data[i])
        }
      } else if (data instanceof Object) {
        if (data.hasOwnProperty('event') && data.event === 'pong') {
          return
        }
        data.payload && (data.payload = JSON.parse(data.payload))
        this.doCallback(data)
      }
    }
    doCallback (data) {
      if (data.event) {
        let fn = this.successFn[data.event]
        if (typeof fn === 'function') {
          fn(data)
        }
      }
    }
    // 心跳检测
    heartCheck () {
      let that = this
      this.heartCheck = {
        timeout: 10000, // 10秒
        timeoutObj: null,
        serverTimeoutObj: null,
        reset: function () {
          clearTimeout(this.timeoutObj)
          clearTimeout(this.serverTimeoutObj)
        },
        start: function () {
          this.reset()
          let self = this
          this.timeoutObj = setTimeout(function () {
            // 这里发送一个心跳，后端收到后，返回一个心跳消息
            // onmessage拿到返回的心跳就说明连接正常
            that.send('{"event": "ping"}')
            self.serverTimeoutObj = setTimeout(function () { // 如果超过一定时间还没重置，说明后端主动断开了
              // 如果onclose会执行reconnect，我们执行ws.close()就行了.如果直接执行reconnect 会触发onclose导致重连两次
             that.webSocket.close() 
            }, self.timeout)
          }, this.timeout)
        }
      }
    }
  }
  function webSocketFn (url) {
    let wb = new WebSocketClass(url)
    return {
      webSocketSend: wb.send.bind(wb),
      errorCallBackFunArr: wb.errorCallBackFunArr,
      successFn: wb.successFn,
      isConnection: function () {
        return wb.isConnection
      },
      getSocketFile (webSocketData, ajaxData) {
        let socketFail = (isFirst) => {
         if (this.isConnection()) {
           webSocketData()
         } else {
          ajaxData()
          setTimeout(socketFail, 2000)
         }
       }
       return socketFail
      }
    }
  }