Integrating VoIP into Flutter AppsSIP, CallKit & Push Notifications

import 'package:dart_sip_ua/dart_sip_ua.dart';

class SipService implements SipUaHelperListener {
  final _helper = SipUaHelper();

  void init(String ext, String password, String serverWss) {
    final settings = UaSettings()
      ..webSocketUrl = serverWss  // wss://sip.celloip.com:8089/ws
      ..uri = 'sip:[email protected]'
      ..authorizationUser = ext
      ..password = password
      ..displayName = ext
      ..dtmfMode = DtmfMode.RFC2833;

    _helper.addSipUaHelperListener(this);
    _helper.start(settings);
  }

  @override
  void registrationStateChanged(RegistrationState state) {
    debugPrint('SIP status: ${state.state}');
    // REGISTERED, UNREGISTERED, REGISTRATION_FAILED
  }

  @override
  void callStateChanged(Call call, CallState state) {
    if (state.state == CallStateEnum.CALL_INITIATION) {
      // Show incoming call via flutter_callkit_incoming
      showIncomingCallScreen(call);
    }
  }

  void makeCall(String destination) {
    _helper.call('sip:[email protected]', voiceonly: true);
  }
}

import 'package:flutter_callkit_incoming/flutter_callkit_incoming.dart';

Future<void> showIncomingCallScreen(String callerId, String uuid) async {
  final params = CallKitParams(
    id: uuid,
    nameCaller: callerId,
    appName: 'CelloIP',
    type: 0, // 0 = voice, 1 = video
    duration: 30000,
    android: AndroidParams(
      isCustomNotification: true,
      isShowLogo: false,
      ringtonePath: 'system_ringtone_default',
      backgroundColor: '#1BA8DC',
    ),
    ios: IOSParams(
      iconName: 'CallKitLogo',
      handleType: 'generic',
      supportsVideo: false,
      maximumCallGroups: 1,
      maximumCallsPerCallGroup: 1,
      ringtonePath: 'system_ringtone_default',
    ),
  );
  await FlutterCallkitIncoming.showCallkitIncoming(params);
}

import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter_callkit_incoming/flutter_callkit_incoming.dart';

// Must be top-level function (not a class method)
@pragma('vm:entry-point')
Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  // Extract call info from FCM data message
  final callerId = message.data['caller_id'] ?? 'Unknown';
  final uuid = message.data['call_uuid'] ?? UniqueKey().toString();

  // Show native call screen while app is backgrounded
  await FlutterCallkitIncoming.showCallkitIncoming(
    CallKitParams(
      id: uuid,
      nameCaller: callerId,
      appName: 'CelloIP',
      type: 0,
      duration: 30000,
    ),
  );

  // Re-register SIP so the actual call can connect
  await SipService.instance.reconnect();
}

// Register in main():
// FirebaseMessaging.onBackgroundMessage(firebaseMessagingBackgroundHandler);

// In your WebRTC call setup:
final config = {
  'iceServers': [
    {'urls': 'stun:stun.celloip.com:3478'},
    {
      'urls': 'turn:turn.celloip.com:3478',
      'username': 'webrtc',
      'credential': 'yourTurnPassword',
    }
  ],
  'sdpSemantics': 'unified-plan',
  // DTLS-SRTP is the default in WebRTC — ensure no plaintext fallback:
  'crypto': {
    'dtlsSrtpKeyAgreement': true,
  }
};

final pc = await createPeerConnection(config);
// dart-sip-ua uses this PC for SRTP-encrypted media automatically