//
// UDP server module
//
// Neil Gershenfeld
// (c) Massachusetts Institute of Technology 2016
//
// This work may be reproduced, modified, distributed, performed, and
// displayed for any purpose, but must acknowledge the mods
// project. Copyright is retained and must be preserved. The work is
// provided as is; no warranty is provided, and users accept all
// liability.
//
// closure
//
(function(){
//
// module globals
//
var mod = {}
//
// name
//
var name = 'WebSocket UDP'
//
// initialization
//
var init = function() {
   mod.address.value = '127.0.0.1'
   mod.port.value = '1234'
   mod.localport.value = '2345'
   mod.remotehost.value = '127.0.0.1'
   mod.remoteport.value = '3456'
   mod.socket = null
   socket_open()
   }
//
// inputs
//
var inputs = {
   transmit:{type:'string',
      event:function(evt){
         send_string(evt.detail)
         }}}
//
// outputs
//
var outputs = {
   receive:{type:'string',
      event:function(str){
         mods.output(mod,'receive',str)}}}
//

//
// interface
//
var interface = function(div){
   mod.div = div
   //
   // server
   //
   div.appendChild(document.createTextNode('udpserver:'))
   div.appendChild(document.createElement('br'))
   //
   // open/close
   //
   var btn = document.createElement('button')
      btn.style.margin = 1
      btn.appendChild(document.createTextNode('open'))
      btn.addEventListener('click',function() {
         socket_open()
         })
      div.appendChild(btn)
   var btn = document.createElement('button')
      btn.style.margin = 1
      btn.appendChild(document.createTextNode('close'))
      btn.addEventListener('click',function() {
         socket_close()
         })
      div.appendChild(btn)
   div.appendChild(document.createElement('br'))
   //
   // address
   //
   div.appendChild(document.createTextNode('address: '))
   input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.address = input
   div.appendChild(document.createElement('br'))
   //
   // port
   //
   div.appendChild(document.createTextNode('\u00a0\u00a0\u00a0\u00a0\u00a0port: '))
   input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.port = input
   div.appendChild(document.createElement('br'))
   //
   // status
   //
   div.appendChild(document.createTextNode('\u00a0\u00a0status: '))
   input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.status = input
   div.appendChild(document.createElement('br'))
   //
   // local
   //
   div.appendChild(document.createTextNode('local UDP:'))
   div.appendChild(document.createElement('br'))
   //
   // host
   //
   div.appendChild(document.createTextNode('\u00a0\u00a0\u00a0\u00a0\u00a0host: '))
   var input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.localhost = input
   div.appendChild(document.createElement('br'))
   //
   // port
   //
   div.appendChild(document.createTextNode('\u00a0\u00a0\u00a0\u00a0\u00a0port: '))
   var input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.localport = input
   div.appendChild(document.createElement('br'))
   //
   // remote
   //
   div.appendChild(document.createTextNode('remote UDP:'))
   div.appendChild(document.createElement('br'))
   //
   // host
   //
   div.appendChild(document.createTextNode('\u00a0\u00a0\u00a0\u00a0\u00a0host: '))
   var input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.remotehost = input
   div.appendChild(document.createElement('br'))
   //
   // port
   //
   div.appendChild(document.createTextNode('\u00a0\u00a0\u00a0\u00a0\u00a0port: '))
   var input = document.createElement('input')
      input.type = 'text'
      input.size = 10
      div.appendChild(input)
      mod.remoteport = input
   }
//
// local functions
//
function socket_open() {
   var url = "ws://"+mod.address.value+':'+mod.port.value
   mod.socket = new WebSocket(url)
   mod.socket.onopen = function(event) {
      mod.status.value = "socket opened"
      open_local()
      }
   mod.socket.onerror = function(event) {
      mod.status.value = "can not open"
      mod.socket = null
      }
   mod.socket.onmessage = function(event) {
      var msg = JSON.parse(event.data)
      if (msg.type == 'status')
         mod.status.value = msg.status
      else if (msg.type == 'listening') {
         mod.status.value = msg.status
         mod.localhost.value = msg.addresses
         }
      else if (msg.type == 'message') {
         outputs.receive.event(msg.message)
         mod.status.value = 'receive '+JSON.stringify(msg.info)
         }
      }
   }
function socket_close() {
   mod.socket.close()
   mod.status.value = "socket closed"
   mod.socket = null
   }
function socket_send(msg) {
   if (mod.socket != null) {
      mod.status.value = "send"
      mod.socket.send(msg)
      }
   else {
      mod.status.value = "can't send, not open"
      }
   }
function open_local() {
   if (mod.socket == null) {
      mod.status.value = "socket not open"
      }
   else {
      var msg = {}
      msg.type = 'open local'
      msg.port = parseInt(mod.localport.value)
      mod.socket.send(JSON.stringify(msg))
      }
   }
function send_string(str) {
   if (mod.socket == null) {
      mod.status.value = "socket not open"
      }
   else {
      var msg = {}
      msg.type = 'send string'
      msg.host = mod.remotehost.value
      msg.port = parseInt(mod.remoteport.value)
      msg.string = str
      mod.socket.send(JSON.stringify(msg))
      mod.status.value = 'transmit'
      }
   }
//
// return values
//
return ({
   mod:mod,
   name:name,
   init:init,
   inputs:inputs,
   outputs:outputs,
   interface:interface
   })
}())