import 'dart:convert';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter_webrtc/flutter_webrtc.dart';

typedef void StreamStateCallback(MediaStream stream);

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

  RTCPeerConnection peerConnection;
  MediaStream localStream;
  MediaStream remoteStream;
  String roomId;
  String currentRoomText;
  StreamStateCallback onAddRemoteStream;

  Future<String> createRoom(RTCVideoRenderer remoteRenderer) async {
    FirebaseFirestore db = FirebaseFirestore.instance;
    DocumentReference roomRef = db.collection('rooms').doc();

    print('Create PeerConnection with configuration: $configuration');

    peerConnection = await createPeerConnection(configuration);

    registerPeerConnectionListeners();

    localStream.getTracks().forEach((track) {
      peerConnection?.addTrack(track, localStream);
    });

    // Code for collecting ICE candidates below
    var callerCandidatesCollection = roomRef.collection('callerCandidates');

    peerConnection?.onIceCandidate = (RTCIceCandidate candidate) {
      print('Got candidate: ${candidate.toMap()}');
      callerCandidatesCollection.add(candidate.toMap());
    };
    // Finish Code for collecting ICE candidate

    // Add code for creating a room
    RTCSessionDescription offer = await peerConnection.createOffer();
    await peerConnection.setLocalDescription(offer);
    print('Created offer: $offer');

    Map<String, dynamic> roomWithOffer = {'offer': offer.toMap()};

    await roomRef.set(roomWithOffer);
    var roomId = roomRef.id;
    print('New room created with SDK offer. Room ID: $roomId');
    currentRoomText = 'Current room is $roomId - You are the caller!';
    // Created a Room

    peerConnection?.onTrack = (RTCTrackEvent event) {
      print('Got remote track: ${event.streams[0]}');

      event.streams[0].getTracks().forEach((track) {
        print('Add a track to the remoteStream $track');
        remoteStream?.addTrack(track);
      });
    };

    // Listening for remote session description below
    roomRef.snapshots().listen((snapshot) async {
      print('Got updated room: ${snapshot.data()}');

      Map<String, dynamic> data = snapshot.data() as Map<String, dynamic>;
      if (peerConnection?.getRemoteDescription() != null && data['answer'] != null) {
        var answer = RTCSessionDescription(
          data['answer']['sdp'],
          data['answer']['type'],
        );

        print("Someone tried to connect");
        await peerConnection?.setRemoteDescription(answer);
      }
    });
    // Listening for remote session description above

    // Listen for remote Ice candidates below
    roomRef.collection('calleeCandidates').snapshots().listen((snapshot) {
      snapshot.docChanges.forEach((change) {
        if (change.type == DocumentChangeType.added) {
          Map<String, dynamic> data = change.doc.data() as Map<String, dynamic>;
          print('Got new remote ICE candidate: ${jsonEncode(data)}');
          peerConnection.addCandidate(
            RTCIceCandidate(
              data['candidate'],
              data['sdpMid'],
              data['sdpMLineIndex'],
            ),
          );
        }
      });
    });
    // Listen for remote ICE candidates above

    return roomId;
  }

  Future<void> joinRoom(String roomId, RTCVideoRenderer remoteVideo) async {
    FirebaseFirestore db = FirebaseFirestore.instance;
    DocumentReference roomRef = db.collection('rooms').doc('$roomId');
    var roomSnapshot = await roomRef.get();
    print('Got room ${roomSnapshot.exists}');

    if (roomSnapshot.exists) {
      print('Create PeerConnection with configuration: $configuration');
      peerConnection = await createPeerConnection(configuration);

      registerPeerConnectionListeners();

      localStream.getTracks().forEach((track) {
        peerConnection?.addTrack(track, localStream);
      });

      // Code for collecting ICE candidates below
      var calleeCandidatesCollection = roomRef.collection('calleeCandidates');
      peerConnection.onIceCandidate = (RTCIceCandidate candidate) {
        if (candidate == null) {
          print('onIceCandidate: complete!');
          return;
        }
        print('onIceCandidate: ${candidate.toMap()}');
        calleeCandidatesCollection.add(candidate.toMap());
      };
      // Code for collecting ICE candidate above

      peerConnection?.onTrack = (RTCTrackEvent event) {
        print('Got remote track: ${event.streams[0]}');
        event.streams[0].getTracks().forEach((track) {
          print('Add a track to the remoteStream: $track');
          remoteStream?.addTrack(track);
        });
      };

      // Code for creating SDP answer below
      var data = roomSnapshot.data() as Map<String, dynamic>;
      print('Got offer $data');
      var offer = data['offer'];
      await peerConnection?.setRemoteDescription(
        RTCSessionDescription(offer['sdp'], offer['type']),
      );
      var answer = await peerConnection.createAnswer();
      print('Created Answer $answer');

      await peerConnection.setLocalDescription(answer);

      Map<String, dynamic> roomWithAnswer = {
        'answer': {'type': answer.type, 'sdp': answer.sdp}
      };

      await roomRef.update(roomWithAnswer);
      // Finished creating SDP answer

      // Listening for remote ICE candidates below
      // roomRef.collection('callerCandidates').snapshots().listen((snapshot) {
      //   snapshot.docChanges.forEach((document) {
      //     var data = document.doc.data() as Map<String, dynamic>;
      //     print(data);
      //     print('Got new remote ICE candidate: $data');
      //     peerConnection.addCandidate(
      //       RTCIceCandidate(
      //         data['candidate'],
      //         data['sdpMid'],
      //         data['sdpMLineIndex'],
      //       ),
      //     );
      //   });
      // });
    }
  }

  Future<void> openUserMedia(
    RTCVideoRenderer localVideo,
    RTCVideoRenderer remoteVideo,
  ) async {
    var stream = await navigator.mediaDevices.getUserMedia({'video': true, 'audio': false});

    localVideo.srcObject = stream;
    localStream = stream;

    remoteVideo.srcObject = await createLocalMediaStream('key');
  }

  Future<void> hangUp(RTCVideoRenderer localVideo) async {
    List<MediaStreamTrack> tracks = localVideo.srcObject.getTracks();
    tracks.forEach((track) {
      track.stop();
    });

    if (remoteStream != null) {
      remoteStream.getTracks().forEach((track) => track.stop());
    }
    if (peerConnection != null) peerConnection.close();

    if (roomId != null) {
      var db = FirebaseFirestore.instance;
      var roomRef = db.collection('rooms').doc(roomId);
      var calleeCandidates = await roomRef.collection('calleeCandidates').get();
      calleeCandidates.docs.forEach((document) => document.reference.delete());

      var callerCandidates = await roomRef.collection('callerCandidates').get();
      callerCandidates.docs.forEach((document) => document.reference.delete());

      await roomRef.delete();
    }

    localStream.dispose();
    remoteStream?.dispose();
  }

  void registerPeerConnectionListeners() {
    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');
    };

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

    peerConnection?.onAddStream = (MediaStream stream) {
      print("Add remote stream");
      onAddRemoteStream?.call(stream);
      remoteStream = stream;
    };
  }
}