import { Socket } from 'net'
import path from 'path'
import { promisify } from 'util'
import pause from 'delay'
import btc from 'better-try-catch'
import JsonStream from './json-stream'

// import logger from '../../uci-logger/src/logger'
import logger from '@uci-utils/logger'

let log = {}

// TODO change default pipe dir for windows and mac os
const DEFAULT_PIPE_DIR = process.env.SOCKETS_DIR || '/tmp/UCI'
const DEFAULT_SOCKET_NAME = 'uci-sock'

/**
 * Socket Consumer - connects to UCI TCP or Named Pipe Sockets and coummunicates with uci packet.<br/>
 * Extends {@link https://nodejs.org/api/net.html#net_class_net_socket | nodejs net.Socket}
 *  @extends Socket
 */
class SocketConsumer extends Socket {
  /**
   * constructor - Description
   *
   * @param {object} [opts={}] test
   */

  constructor(opts = {}) {
    super()
    log = logger({
      file: 'src/consumer.js',
      class: 'Consumer',
      name: 'socket',
      id: this.id
    })
    this.id = opts.id || opts.name || 'socket:' + new Date().getTime()
    if (!opts.path) {
      if(!opts.host) log.warn({method:'constructor', line:38, opts: opts, msg:'no host supplied using localhost...use named piped instead - opts.path'})
      opts.host = opts.host || '127.0.0.1'
      opts.port = opts.port || 8080
    } else {
      if (typeof opts.path === 'boolean')
        opts.path = path.join(DEFAULT_PIPE_DIR, DEFAULT_SOCKET_NAME)
      if (path.dirname(opts.path) === '.')
        opts.path = path.join(DEFAULT_PIPE_DIR, opts.path)
    }
    this.opts = opts
    // default is keepAlive true, must set to false to explicitly disable
    // if keepAlive is true then consumer will also be reconnecting consumer
    this.initTimeout = opts.initTimeout * 1000 || 60000
    this.retryWait = opts.retryWait * 1000 || 3000
    this.keepAlive = 'keepAlive' in opts ? opts.keepAlive : true
    this._ready = false
    this.stream = new JsonStream()
    // bind to class for other class functions
    this.connect = this.connect.bind(this)
    this.close = promisify(this.end).bind(this)
    // this.__ready = this.__ready.bind(this)
    this._conAttempt = 1
    this._aborted = false
    this._reconnect = false
    // this._write = this._write.bind(this)
  }

  async connect() {
    return new Promise((resolve, reject) => {

      if (this.opts.host === '127.0.0.1'|| this.opts.host ==='localhost')
        log.warn({method:'connect', line:107, msg:'tcp consumer on same machine as host, use named Pipe(Unix) Socket Instead'})

      log.debug('first connnect attempt for', this.opts.name)

      let initTimeout = setTimeout(() => {
        this.removeAllListeners()
        log.fatal({method:'connect', line:69, opts: this.opts, msg:`unable to initially connect to ${this.opts.name} in ${this.initTimeout/1000} secs no more attempts!`})
        this.removeAllListeners()
        this.stream.removeAllListeners()
        this.destroy()
        reject({ opts: this.opts, msg: `unable to connect initially to socket server in ${this.initTimeout/1000} secs, giving up no more attempts`})
      }
        , this.initTimeout)


      const initialHandshake = async (packet) => {
        if (packet._handshake) {
          log.debug({method:'connect', line:87, msg:'handshake received ready for communication'})
          this.stream.removeAllListeners('message')
          this.removeListener('error',initialErrorHandler)
          clearTimeout(initTimeout)
          this._listen() // setup for active connection
          this._ready = true
          this.emit('connection','connected')
          resolve('initial connection successful')
        }
      }

      const initialConnectHandler = async () => {
        this.on('data', this.stream.onData)
        this.stream.on('message', initialHandshake.bind(this))
        log.debug({method:'connect', line:113, msg:'connected waiting for socket ready handshake'})
      }

      const initialErrorHandler = async (err) => {
        log.debug({method:'connect', line:101, error:err, msg:`error during initial connect, trying again in ${this.retryWait/1000} secs`})
        await pause(this.retryWait)
        super.connect(this.opts)
      }


      this.once('connect', initialConnectHandler)
      this.on('error', initialErrorHandler)
      super.connect(this.opts)

    }) // end initial promise
  }

  async send(ipacket) {
    return new Promise(async resolve => {
      if (!this._ready) resolve({ error: 'socket consumer not connected, aborting send' })
      let packet = Object.assign({}, ipacket)  // need to avoid mutuation for different consumers using same packet instance
      setTimeout(() => {resolve({ error: 'no response from socket in 10sec' })}, 10000)
      packet._header = {
        id: Math.random()
          .toString()
          .slice(2), // need this for when multiple sends for different consumers use same packet instanceack
        sender: { name: this.name, instanceID: this.id },
        path: this.opts.path,
        port: this.opts.port,
        host: this.opts.host
      }
      let [err, res] = await btc(this.stream.serialize)(packet)
      if (err)
        resolve({error: 'unable to serialize packet for sending',packet: packet})
      await this.__write(res)
      this.once(packet._header.id, async function(reply) {
        let res = await this._packetProcess(reply)
        if (!res) { // if packetProcess was not promise
          res = reply
          log.debug({method:'send', line:180, msg:'consumer function was not promise returning further processing may be out of sequence'})
        }
        resolve(res)  // resolves processed packet not return packet
      }) //end listener
    })
  }

  // TODO register user alt stream processor (emit 'message' with JSON, serialize function, onData method for raw socket chucks)

  registerPacketProcessor(func) {
    this._packetProcess = func
  }

  // PRIVATE METHODS

  // set up incoming message listening and error/reonnect handling
  async _listen() {
    // Define Handlers and Other Functions
    const reconnectHandler = () => {
      this.stream.once('message', handshake.bind(this))
      log.debug({method:'connect', line:113, msg:'connected waiting for socket ready handshake'})
    }

    const handshake = async (packet) => {
      if (packet._handshake) {
        log.debug({method:'connect', line:87, msg:'handshake received ready for communication'})
        this.stream.on('message', messageProcess.bind(this))
        if (this.keepAlive) { // only attempt reconnect if keepAlive is set which it is by default
          this.on('ping',pingHandler)
          this.setKeepAlive(this.keepAlive,3000)  // keep connection alive unless disabled
        }
        this._ready = true
        this.emit('connection','reconnected')
      }
    }

    const errorHandler = async (err) => {
      log.debug({msg:'connection error emitted ', error:err})
      this._ready = false
      if (err.code !== 'EISCONN') {
        this.emit('connection', err)
        log.debug({ method:'connect', line:130, error: err.code, msg:`connect error ${err.code}, attempting reconnect after ${this.retryWait/1000} secs`})
        await pause(this.retryWait)
        this.stream.removeAllListeners('message') // remove regular message handler in prep for reconnect
        this.removeAllListeners('connect')
        this.once('connect',reconnectHandler)
        super.connect(this.opts)
      }
      else {
        this._ready = true
        this.emit('connection','reconnected')
        log.error({method:'connect', line:69, msg:'reconnected to socket, ready to go again'})
      }
    }

    async function messageProcess(packet) {
      log.debug('incoming packet from socket sever',packet)
      this.emit(packet._header.id, packet)
    }

    const pushHandler = async (packet) => {
      // TODO do some extra security here?
      log.debug('packed was pushed from socket sever, processing',packet)
      let res = await this._packetProcess(packet)
      if (!res) {
        // if process was not promise returning then res will be undefined
        log.debug('consumer packet processing function was not promise returning')
      }
    }

    const pingHandler = async (packet) => {
      clearTimeout(pingTimeout)
      log.info({method:'connect', line:191, msg:'received ping, restting timeout'})
      this._pingTimeout= packet.pingInterval + 1000
      monitorPing.call(this)
    }

    let pingTimeout = {}
    function monitorPing () {
      pingTimeout = setTimeout( () => {
        log.error({method:'connect', line:142, msg:'socket (server) not availabe'})
        this.removeAllListeners('ping')
        this._ready = false
        this.emit('error', { code: 'PING-FAILED' })
      },this._pingTimeout)
    }

    // Start Message Listening and Error/Reconnect Handling
    log.debug('listening for incoming packets from socket')
    this.stream.on('message', messageProcess.bind(this))
    this.setKeepAlive(this.keepAlive,3000)  // keep connection alive unless disabled
    this.on('pushed', pushHandler )
    this.on('error', errorHandler)
    if (this.keepAlive) { // keepAlive also activates ping Monitor
      this.on('ping',pingHandler)
    }
  }

  async __write(packet) {
    // timeout already set if sockect can't be drained in 10 secs
    return new Promise(resolve => {
      const cb = () => resolve('packet written to consumer side socket stream ')
      if (!super.write(packet)) {
        this.once('drain', cb)
      } else {
        process.nextTick(cb)
      }
    })
  }



  // default packet process just a simple console logger.  ignores any cmd: prop
  _packetProcess(packet) {
    console.log('default consumer processor -- log packet from socket to console')
    console.log('replace by calling .registerPacketProcessor(func) with your function')
    console.dir(packet)
  }

} // end class

export default SocketConsumer


// _removeListeners(events) {
//   if (!events) this.removeAllListeners()
//   else {
//     if (typeof events === 'string') this.removeAllListeners(events)
//     else events.map(event => this.removeAllListeners(event))
//   }
// }

// Helper Functions
// wait until a passed ready function returns true
// function isReady(ready, wait = 100, timeout = 2000) {
//   let time = 0
//   return new Promise((resolve, reject) => {
//     (function waitReady() {
//       if (time > timeout)
//         return reject(
//           `timeout waiting for socket ready handshake - ${timeout}ms`
//         )
//       if (ready()) return resolve('ready')
//       log.debug({function:'isReady', line:261, msg:`waiting ${wait}ms for handshake`})
//       time += wait
//       setTimeout(waitReady, wait)
//     })()
//   })
// }