import { Server } from 'net'
import { unlink as fileDelete } from 'fs'
import btc from 'better-try-catch'
import Logger from 'simple-node-logger'
import ON_DEATH from 'death' //this is intentionally ugly

let logger = {
  logFilePath:'logfile.log',
  timestampFormat:'YYYY-MM-DD HH:mm:ss.SSS'
}

export default class Socket extends Server {
  constructor (path, opts={}) {
    super()
    this.path = path
    this.logger = Logger.createSimpleLogger(opts.logger ?  opts.logger: logger)
  } // end constructor


  async create ( app ) {

    this.on('error', async (err) => {
      // recover from socket file that was not removed
      if (err.code === 'EADDRINUSE') {
        console.log(`socket path ${this.path} already exists...deleting`)
        await fileDelete(this.path)
        await this.listen(this.path)
        return Promise.resolve(err.code)
      }
      // otherwise fatally exit
      console.log('error creating socket: ',err.code)
      return Promise.reject(err.code)
    })

    //
    this.on('listening', async () => {
      console.log(`socket created at ${this.path}`)

      // this gets called for each client connection and is unique to each
      this.on('connection', (socket) => {
        console.log('new consumer connected')

        socket.on('data', async (buf) => {
          let [err, packet] = btc(JSON.parse)(buf.toString())
          if (!err) {
            this.logger.info(`data packet received to socket \n ${packet}`)
            socket.write(JSON.stringify(await app.processPacket.bind(app)(packet)))
          }
          else { console.log(`bad packet JSON syntax \n ${buf.toString()}`)}

        }) // end incoming data listerner

      }) // end connected consumer
    }) // end socket listening listener

    // start it
    await this.listen(this.path)

    // if socket is terminated then shutdown gracefully
    ON_DEATH( async () => {
      await this.destroy()
    })

    process.once('SIGUSR2', async () => {
      await this.destroy
      process.kill(process.pid, 'SIGUSR2')

    })

  } // end create

  async destroy () {

    console.log('\nclosing down socket')
    await this.close()
    console.log('\n all connections closed....exiting')
    process.exit()

  } // end destroy


} // end class