class Self {
   uuid = null
   connections = []
   
   constructor() {
      this.connections.push(new Stream(this.id(), {audio: true, video: true}))
   }

   start(isCaller) {
      for(var i of this.connections)
         i.start(isCaller)
   }

   id() {
      this.uuid = this.get("uuid")
      if (!this.uuid) {
         s4 = () => Math.floor((1 + Math.random()) * 0x10000).toString(16).substring(1)
         this.uuid = s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4();
         this.set("uuid", this.uuid)
      }
      return this.uuid
   }

   get(k) {
      var name = k + "=";
      var decodedCookie = decodeURIComponent(document.cookie);
      var ca = decodedCookie.split(';');
      for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
          c = c.substring(1);
        }
        if (c.indexOf(name) == 0) {
          return c.substring(name.length, c.length);
        }
      }
      return "";
   }

   set(k, v) {
      var d = new Date();
      d.setTime(d.getTime() + (1*24*60*60*1000));
      var expires = "expires="+ d.toUTCString();
      document.cookie = k + "=" + v + ";" + expires + ";path=/";
   }
}

class Stream {
   serverConnection = null
   localVideo = null
   remoteVideo = null
   localStream = null
   id = null

   constructor(id, config) {
      if (config.audio) {
         id += "a"
      }
      if (config.video) {
         id += "v"
      }
      this.id = id

      this.serverConnection = new WebSocket('wss://' + window.location.hostname + '/abc?uuid=' + this.id)
      this.serverConnection.onmessage = (m) => this.gotMessageFromServer(m)

      if(navigator.mediaDevices.getUserMedia) {
         navigator.mediaDevices
            .getUserMedia(config)
            .then((s) => this.getUserMediaSuccess(s))
            .catch((e) => this.errorHandler(e))
      } else {
         throw new Exception('Your browser does not support getUserMedia API')
      }
   }

   start(isCaller) {
      this.peerConnection = new RTCPeerConnection({
         'iceServers': [
            {'urls': 'stun:stun.stunprotocol.org:3478'},
            {'urls': 'stun:stun.l.google.com:19302'},
         ]
      });

      this.peerConnection.onicecandidate = (e) => this.gotIceCandidate(e);
      this.peerConnection.ontrack = (e) => this.gotRemoteStream(e);
      this.peerConnection.addStream(this.localStream);

      if(isCaller) {
        this.peerConnection
          .createOffer({
            'iceRestart': true,
            'voiceActivityDetection': true,
          })
          .then((d) => this.createdDescription(d))
          .catch((m) => this.errorHandler(m));
      }
   }

   getUserMediaSuccess(stream) {
      this.localVideo = document.getElementById('localVideo');
      this.remoteVideo = document.getElementById('remoteVideo');

      this.localStream = stream;
      this.localVideo.srcObject = stream;
   }

   gotMessageFromServer(message) {
     if(!this.peerConnection) start(false);
   
     var signal = JSON.parse(message.data);
   
     // Ignore messages from ourself
     if(signal.uuid == this.id) return;
   
     if(signal.sdp) {
       this.peerConnection.setRemoteDescription(new RTCSessionDescription(signal.sdp)).then(function() {
         // Only create answers in response to offers
         if(signal.sdp.type == 'offer') {
           this.peerConnection
              .createAnswer()
              .then((d) => this.createdDescription(d))
              .catch((e) => this.errorHandler(e));
         }
       }).catch((e) => this.errorHandler(e));
     } else if(signal.ice) {
        this.peerConnection
           .addIceCandidate(new RTCIceCandidate(signal.ice))
           .catch((e) => this.errorHandler(e));
     }
   }
   
   gotIceCandidate(event) {
     if(event.candidate != null) {
       this.serverConnection
         .send(JSON.stringify({
            'ice': event.candidate, 
            'uuid': this.id,
         }));
     }
   }
   
   createdDescription(description) {
     console.log('got description');
   
     this.peerConnection
       .setLocalDescription(description)
       .then(() => {
         this.serverConnection.send(JSON.stringify({
            'sdp': this.peerConnection.localDescription, 
            'uuid': this.id,
         }));
       })
       .catch((e) => this.errorHandler(e));
   }
   
   gotRemoteStream(event) {
     console.log('got remote stream');
     this.remoteVideo.srcObject = event.streams[0];
   }
   
   errorHandler(error) {
     console.log(error);
   }
}

var self

function pageReady() {
   self = new Self()
}

function start(isCaller) {
   self.start(isCaller)
}