initConnection method Null safety

Implementation

initConnection(Map<String, dynamic> data) async {
  _logger.d('Viewer connect options values: $options');

  if (isActive() && !data['migrate']) {
    _logger.w('Viewer currently subscribed');
    throw Error();
  }
  MillicastDirectorResponse subscriberData;
  try {
    subscriberData = await tokenGenerator();
  } catch (e) {
    _logger.e('Error generating token.');
    throw Exception(e);
  }
  // ignore: unnecessary_null_comparison
  if (subscriberData == null) {
    _logger.e('Error while subscribing. Subscriber data required');
  }
  var signalingInstance = Signaling({
    'streamName': streamName,
    'url': '${subscriberData.urls[0]}?token=${subscriberData.jwt}'
  });

  var webRTCPeerInstance = data['migrate'] ? PeerConnection() : webRTCPeer;
  await webRTCPeerInstance.createRTCPeer(options?['peerConfig']);

  // Stop emiting events from the previous instances
  if (stopReemitingWebRTCPeerInstanceEvents != null) {
    stopReemitingWebRTCPeerInstanceEvents!();
  }
  if (stopReemitingSignalingInstanceEvents != null) {
    stopReemitingSignalingInstanceEvents!();
  }

  stopReemitingWebRTCPeerInstanceEvents = reemit(webRTCPeerInstance, this,
      [webRTCEvents['track'], webRTCEvents['connectionStateChange']]);

  stopReemitingSignalingInstanceEvents =
      reemit(signalingInstance, this, [SignalingEvents.broadcastEvent]);

  Future getLocalSDPFuture = webRTCPeerInstance
      .getRTCLocalSDP(options: {...options!, 'stereo': true});
  Future signalingConnectFuture = signalingInstance.connect();

  Iterable<Future<dynamic>> iterFuture = [
    getLocalSDPFuture,
    signalingConnectFuture
  ];
  var resolvedFutures = await Future.wait(iterFuture);
  String localSdp = resolvedFutures[0];

  Future subscribeFuture =
      signalingInstance.subscribe(localSdp, options: options);
  Future<void>? setLocalDescriptionFuture = webRTCPeerInstance.peer
      ?.setLocalDescription(webRTCPeerInstance.sessionDescription!);
  iterFuture = [subscribeFuture, setLocalDescriptionFuture!];

  resolvedFutures = await Future.wait(iterFuture);
  String remoteSdp = resolvedFutures[0];

  await webRTCPeerInstance.setRTCRemoteSDP(remoteSdp);
  _logger.i('Connected to streamName: $streamName');
  Signaling? oldSignlaling = signaling;
  PeerConnection? oldWebRTCPeer = webRTCPeer;
  signaling = signalingInstance;
  webRTCPeer = webRTCPeerInstance;

  emit(SignalingEvents.connectionSuccess, this);

  setReconnect();

  if (data['migrate']) {
    webRTCPeer.on(webRTCEvents['connectionStateChange'], webRTCPeer,
        (ev, context) async {
      if (ev.eventData ==
          RTCIceConnectionState.RTCIceConnectionStateConnected) {
        Timer(const Duration(milliseconds: 1000), () {
          oldSignlaling?.close();
          oldWebRTCPeer?.closeRTCPeer();
          oldSignlaling = null;
          oldWebRTCPeer = null;
          _logger.i('Current connection migrated');
        });
      } else if ([
        RTCIceConnectionState.RTCIceConnectionStateClosed,
        RTCIceConnectionState.RTCIceConnectionStateFailed,
        RTCIceConnectionState.RTCIceConnectionStateDisconnected
      ].contains(ev.eventData)) {
        oldSignlaling?.close();
        oldWebRTCPeer?.closeRTCPeer();
        oldSignlaling = null;
        oldWebRTCPeer = null;
      }
    });
  }
}