PatientApp-KKUMC/lib/pages/webRTC/signaling.dart

import 'dart:convert';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:diplomaticquarterapp/pages/webRTC/fcm/FCMSendNotification.dart';
import 'package:diplomaticquarterapp/uitl/SignalRUtil.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter_webrtc/flutter_webrtc.dart';

import 'call_page.dart';

typedef void StreamStateCallback(MediaStream stream);
typedef void RTCIceGatheringStateCallback(RTCIceGatheringState state);
typedef void RTCPeerConnectionStateCallback(RTCPeerConnectionState state);
typedef void RTCSignalingStateCallback(RTCSignalingState state);

class Signaling {

  dispose(){
    if(peerConnection != null)
      peerConnection.dispose();
    signalR.closeConnection();
  }

  init(){
    // Create Peer Connection
    createPeerConnection(configuration).then((value){
      peerConnection = value;
      registerPeerConnectionListeners();
    });
  }


  initializeSignalR() async{
    if(signalR != null)
      await signalR.closeConnection();

    signalR = SignalRUtil(hubName: "https://VCallApi.hmg.com/WebRTCHub?source=$My_Mobile&username=$My_ID");
    final connected = await signalR.openConnection();
    if(!connected)
      throw 'Failed to connect SignalR';
  }

  Map<String, dynamic> configuration = {
    'iceServers': [
      {
        'urls': ['stun:stun1.l.google.com:19302', 'stun:stun2.l.google.com:19302']
      }
    ]
  };

  SignalRUtil signalR;

  RTCPeerConnection peerConnection;
  MediaStream localStream;
  MediaStream remoteStream;
  RTCDataChannel dataChannel;

  Future<bool> call(String patientId, String mobile,  {@required RTCVideoRenderer localVideo, @required RTCVideoRenderer remoteVideo}) async {
    initializeSignalR();

    final isCallPlaced = await FCM.sendCallNotifcationTo(DOCTOR_TOKEN, patientId, mobile);
    if(!isCallPlaced)
      throw 'Failed to notify target for call';

    return isCallPlaced;
  }


  Future<bool> acceptCall(String caller, String receiver, {@required MediaStream localMediaStream, @required Function(MediaStream) onRemoteMediaStream}) async{
    await initializeSignalR();
    signalR.setContributors(caller: caller, receiver: receiver);
    await signalR.acceptCall(receiver, caller).catchError((e) => throw 'Failed to inform signalR that i accepted a call');

    peerConnection.addStream(localMediaStream);

    peerConnection?.onAddStream = (MediaStream stream) {
      remoteStream = stream;
      onRemoteMediaStream?.call(stream);
    };

    return true;
  }

  Future hangupCall(String caller, String receiver) async{
    await signalR.hangupCall(caller, receiver);
    dispose();
  }

  answerOffer(String sdp) async{
    final offer = jsonDecode(sdp);
    final caller = offer['caller'];
    final receiver = offer['target'];
    final offerSdp = offer['sdp'];
    peerConnection.setRemoteDescription(rtcSessionDescriptionFrom(offerSdp))
        .then((value) {
      return peerConnection.createAnswer();
    })
        .then((anwser) {
      return peerConnection.setLocalDescription(anwser);
    })
        .then((value) {
      return peerConnection.getLocalDescription();
    })
        .then((answer) {
      return signalR.answerOffer(answer, caller, receiver);
    });

  }

  Future<void> hangUp(RTCVideoRenderer localVideo) async {

  }

  Future<String> createSdpAnswer(String toOfferSdp) async {
    final offerSdp = rtcSessionDescriptionFrom(jsonDecode(toOfferSdp));
    peerConnection.setRemoteDescription(offerSdp);

    final answer = await peerConnection.createAnswer();
    var answerSdp = json.encode(answer); // Send SDP via Push or any channel
    return answerSdp;
  }

  Future<String> createSdpOffer() async {
    final offer = await peerConnection.createOffer();
    await peerConnection.setLocalDescription(offer);
    final map = offer.toMap();
    var offerSdp = json.encode(map); // Send SDP via Push or any channel
    return offerSdp;
  }

  addCandidate(String candidateJson){
    peerConnection.addCandidate(rtcIceCandidateFrom(candidateJson));
  }

  void registerPeerConnectionListeners() {
    peerConnection.onIceCandidate = (RTCIceCandidate candidate){
      print(json.encode(candidate.toMap()));
      signalR.addIceCandidate(json.encode(candidate.toMap()));
    };

    peerConnection?.onIceGatheringState = (RTCIceGatheringState state) {
      print('ICE gathering state changed: $state');
    };

    peerConnection?.onConnectionState = (RTCPeerConnectionState state) {
      print('Connection state change: $state');
    };

    peerConnection?.onSignalingState = (RTCSignalingState state) {
      print('Signaling state change: $state');
    };
  }
}


rtcSessionDescriptionFrom(Map sdp){
  return RTCSessionDescription(
    sdp['sdp'],sdp['type'],
  );
}

rtcIceCandidateFrom(String json){
  final map = jsonDecode(json)['candidate'];
  return RTCIceCandidate(map['candidate'], map['sdpMid'], map['sdpMLineIndex']);
}