(function (exports) {
  exports.WsRpc = function () {
    var ctx = this
    this._requests = {}
    /**
     * Connect with reconnection
     */
    this.connect = function (loc) {
      var ws = this.ws = new window.WebSocket(loc)
      ws.onopen = function () {
        ctx._requests = {}
        ctx.connected = true
        if (ctx.onopen !== undefined) {
          ctx.onopen(ctx)
        }
      }
      ws.onmessage = function (evt) {
        // console.log("RCV:",evt.data)
        var obj = JSON.parse(evt.data)
        var arrObj = [].concat(obj) // if object add, if array concat
        for (var i = 0; i < arrObj.length; i++) {
          ctx.process(arrObj[i])
        }
      }
      ws.onerror = function () { }
      ws.onclose = function () {
        if (ctx.connected === true) {
          ctx.connected = false
          if (ctx.onclose !== undefined) {
            ctx.onclose(ctx)
          }
        }
        // Retry
        setTimeout(function () {
          ctx.connect(loc)
        }, 3000) // 3 seconds reconnect
      }
    }
    /**
     * Process requests
     */
    this.process = function (obj) {
      switch (obj.op) {
        case 'call':
          if (obj.method === undefined || this._exports[obj.method] === undefined) {
            var dataObj = { 'op': 'response', 'id': obj.id, 'error': 'Method not found' }
            ctx.ws.send(JSON.stringify(dataObj))
            return
          }
          // Send response
          var nparams = [].concat(function (data) {
            var dataObj = {
              'op': 'response',
              'id': obj.id,
              'response': data
            }
            ctx.ws.send(JSON.stringify(dataObj))
          }, obj.params)
          this._exports[obj.method].apply(this._exports[obj.method], nparams)
          break
        case 'response':
          ctx._requests[obj.id](obj.response, obj.error)
          delete ctx._requests[obj.reqId]
          break
      }
    }

    /**
     * Call with variadic params
     */
    this.call = function (method) {
      var aparam = Array.prototype.slice.call(arguments, 1)
      // var aparam = params
      return new Promise(function (resolve, reject) {
        if (ctx.connected === false) {
          reject(Error('Not connected'))
        }

        var uuidStr = uuid()
        var callObj = {
          'op': 'call',
          'id': uuidStr,
          'method': method,
          'params': aparam
        }
        ctx._requests[uuidStr] = (res,err) => {
          if (err !== undefined) {
            reject(err)
            return
          }
          resolve(res)
        }

        // console.log("Sending a call:", method)
        ctx.ws.send(JSON.stringify(callObj)) // if error delete request
      })
    }
    /**
     * Export function, binds export methods
     */
    this.export = function (obj) {
      this._exports = obj
    }

    return this
  }
  function uuid () {
    var ret = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
      var r = Math.random() * 16 | 0
      var v = c === 'x' ? r : (r & 0x3 | 0x8)
      return v.toString(16)
    })
    return ret
  }
})(typeof exports === 'undefined' ? window : exports) // Register directly to window (this)