const ws = require('ws')
const { randomBytes } = require('crypto')
const sleep = (ms) => new Promise((resolve, reject) => setTimeout(resolve, ms))

// 建议把 onopen, onerror, onclose, onmessage 保留给系统使用，例如reconnecting。用户使用 on(event, listener)

const DAD = (module.exports = class RpcSocket extends (
  ws
) {
  constructor(address, protocols, options) {
    let ws = super(address, protocols, options)
    DAD.upgrade(ws)
  }

  static upgrade(ws) {
    ws.__proto__ = DAD.prototype
    ws.sid = randomBytes(16).toString('hex')
    ws.onmessage = async ({ data }) => {
      //      console.log('onmessage 被调用')
      try {
        let obj = JSON.parse(data)
        //        console.log('message data parsed to obj=',obj)
        switch (obj.type) {
          case 'NOTIFY': // 接收到同步的远程调用
            //            console.log(`NOTIFY message: rpc=${obj.rpc}, param=${JSON.stringify(obj.param)}`)
            if (ws.hasOwnProperty(obj.rpc))
              // 作为rpc调用
              ws[obj.rpc](obj.param)
            else if (ws.eventNames().indexOf(obj.rpc) >= 0)
              // 作为event调用
              ws.emit(obj.rpc, obj.param)
            else console.log('onmessage unknown notification')
          case 'REQUEST': // 接收到异步的远程调用
            //            console.log(`被动方 收到 REQUEST: rpc=${obj.rpc}, param=${JSON.stringify(obj.param)}`)
            let result
            if (ws.hasOwnProperty(obj.rpc)) {
              result = await ws[obj.rpc](obj.param)
            } else {
              result = { _state: 'error', error: 'unknown rpc' }
            }
            if (obj.randomEvent) {
              ws.send(
                JSON.stringify({
                  type: 'REPLY',
                  randomEvent: obj.randomEvent,
                  result,
                })
              ) // 返回结果给远程
            }
          case 'REPLY': // 接收到远程返回的结果
            //            console.log('主动方 收到 REPLY: result=', obj.result)
            ws.emit(obj.randomEvent, obj.result)
          default:
        }
      } catch (exception) {
        console.error('Invalid socket message received!')
        return
      }
    }

    return ws
  }

  static connectAsync(url) {
    return new Promise(function (resolve, reject) {
      let socket = new DAD(url)
      socket.onopen = () => resolve(socket)
      socket.onerror = (err) => reject(err)
    })
  }

  reconnectAsync(url) {
    if (this.readyState < 2) {
      return Promise.resolve(this)
    }
    return new Promise((resolve, reject) => {
      let socket = new DAD(url || this.url)
      socket.once('open', () => resolve(socket))
      socket.once('error', (err) => reject(err))
    })
  }

  notify({ rpc, param, options, cb } = {}) {
    // 发起同步的远程调用
    this.send(JSON.stringify({ type: 'NOTIFY', rpc, param, options, cb }))
  }

  requestAsync({ rpc, param, ack, timeout = 5000 } = {}) {
    // 发起异步的远程调用(rpc)
    let randomEvent = randomBytes(16).toString('hex')
    //    console.log('randomEvent is randomized: ', randomEvent)
    if (typeof ack === 'function') {
      // 有回调
      this.send(JSON.stringify({ type: 'REQUEST', rpc, param, randomEvent }), () => {
        //        console.log('in callback, randomEvent=', randomEvent)
        this.once(randomEvent, ack)
        setTimeout(() => {
          if (this.eventNames().indexOf(randomEvent) >= 0) {
            this.removeAllListeners(randomEvent)
            ack({ _state: 'timeout', error: 'timeout happens' })
          }
        }, timeout)
      })
    } else {
      // 没有回调
      return new Promise((resolve, reject) => {
        this.send(JSON.stringify({ type: 'REQUEST', rpc, param, randomEvent }), () => {
          this.once(randomEvent, resolve)
          setTimeout(() => {
            if (this.eventNames().indexOf(randomEvent) >= 0) {
              this.removeAllListeners(randomEvent)
              resolve({ _state: 'timeout', error: 'timeout happens' })
            }
          }, timeout)
        })
      })
    }
  }
})

// (async ()=>{

//   new RpcSocket('http://localhost:9007')
//   await sleep(20000)
//   new RpcSocket.Server({port:9007})
//   await sleep(20000)

// })()

/*
//RpcSocket=require('./Ling/RpcSocket.js'); 
server = new RpcSocket.Server({port:6000}); 
var serverSocket; server.on('connection', (socket)=>{console.log('socket coming'); 
serverSocket = RpcSocket.upgrade(socket).on('close', (code, reason)=>console.log('socket is closed for code and reason: ', code, reason))
.on('error', (errer)=>console.log('socket has error: ', error))
})

RpcSocket.connectAsync('http://localhost:6000').then((clientSocket)=>{
  clientSocket.request('testfunc', {height:99}, (result)=>console.log('using request: ', result), 3000)
  return clientSocket
}).then((clientSocket)=>{
  console.log('sleeping...')
  sleep(2000)
  return clientSocket
}).then(async (clientSocket)=>{
  let result = await clientSocket.requestAsync('testfunc', {height:99}, 3000).catch(console.log)
  console.log('using requestAsync:', result)
  process.exit()
}).catch((e)=>{
  console.log('connect error happens:', e)
})
*/