import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:math';

import 'package:isar/isar.dart';
import 'package:mqtt_client/mqtt_client.dart';
import 'package:mqtt_client/mqtt_server_client.dart';
import 'package:stadtbote/model/rank.dart';
import 'package:stadtbote/model/status.dart';
import 'package:stadtbote/protocoll_messages/bootstrap_request.dart';
import 'package:stadtbote/protocoll_messages/bootstrap_response_payload.dart';
import 'package:stadtbote/model/job.dart';
import 'package:stadtbote/model/message.dart';
import 'package:stadtbote/protocoll_messages/device_object.dart';
import 'package:stadtbote/protocoll_messages/job_del_message.dart';
import 'package:stadtbote/protocoll_messages/start_session_message.dart';
import 'package:stadtbote/protocoll_messages/sync_jobs_message.dart';
import 'package:stadtbote/protocoll_messages/track_message.dart';
import 'package:stadtbote/tools/connection_status.dart';
import 'package:stadtbote/tools/message_service.dart';
import 'package:stadtbote/tools/messages/job_deleted_message.dart';
import 'package:stadtbote/tools/messages/job_received_message.dart';
import 'package:stadtbote/tools/messages/message_message.dart';
import 'package:stadtbote/tools/messages/ranking_updated.dart';
import 'package:stadtbote/tools/messages/session_info_update.dart';
import 'package:stadtbote/tools/messages/status_info_update.dart';
// ignore: depend_on_referenced_packages
import 'package:typed_data/typed_buffers.dart';
import 'package:http/http.dart' as http;

import '../main.dart';
import '../model/session_status.dart';
import 'constants.dart';
import 'util.dart';

enum ConnectionStateEnum {
  notConnected,
  connected
}

class MqttCore {
  static late MqttCore instance;

  late ConnectionStateEnum connectionState = ConnectionStateEnum.notConnected;

  late bool _disconnectInProgress = false;

  late String _brokerUri;
  late int _brokerPort;
  late String _fromServerTopic;
  late String _clientId;
  late String _toServerTopic;

  late MqttServerClient _mqttClient;

  late int _reconnectDelay = 0;

  Timer? _reconnectTimer;

  Timer? _trackTimer;

  MqttCore() {
    _disconnectInProgress = false;

    _processBootstrap();
  }

  static setup() {
    instance = MqttCore();
  }

  diconnect() {
    _disconnectInProgress = true;

    _cancelReconnectTimer();

    _cancelTrackTimer();

    _mqttClient.disconnect();

    connectionState = ConnectionStateEnum.notConnected;
  }

  _connectToBroker() async {
    try {
      String clientId = await Util.getAppUuid();
      Util.logInfo("client id: $clientId");
      Util.logInfo("broker uri: $_brokerUri");
      Util.logInfo("broker port: $_brokerPort");

      _mqttClient = MqttServerClient.withPort(_brokerUri, clientId, _brokerPort);
      _mqttClient.logging(on: false);
      _mqttClient.keepAlivePeriod = 20;
      _mqttClient.autoReconnect = false;
      _mqttClient.onDisconnected = _clientDisconnected;

      _mqttClient.connectionMessage = MqttConnectMessage()
          .withClientIdentifier(await Util.getAppUuid())
          .withWillQos(MqttQos.atMostOnce)
          .withWillTopic('willTopic')
          .withWillMessage('willMessage')
          .authenticateAs("app", "apppwd");

      await _mqttClient.connect();

      if (_mqttClient.connectionStatus?.state == MqttConnectionState.connected) {
        Util.logInfo('Verbunden mit dem MQTT-Broker!');

        _reconnectDelay = 0;

        _setupSubscriptions();

        _initSession();
      } else {
        Util.logInfo('Verbindung zum MQTT-Broker fehlgeschlagen!');

        MessageService().publish<ConnectionStatus>(Constants.messageTopicConnectionStatusChanged, arguments: ConnectionStatus(status: ConnectionStatusEnum.notConnected));

        _startReconnectTimer();
      }

    } catch (ex) {
      _startReconnectTimer();

      Util.logInfo('Verbindung zum MQTT-Broker fehlgeschlagen!: $ex');

      MessageService().publish<ConnectionStatus>(Constants.messageTopicConnectionStatusChanged, arguments: ConnectionStatus(status: ConnectionStatusEnum.notConnected));
    }
  }

  publishText(String subtopic, String text) {
    try {
      var buffer = Uint8Buffer();
      buffer.addAll(utf8.encode(text));

      _mqttClient.publishMessage(subtopic, MqttQos.exactlyOnce, buffer);

      var topic = "$_toServerTopic$subtopic/$_clientId";

      _mqttClient.publishMessage( topic, MqttQos.exactlyOnce, buffer);

      Util.logInfo("send message $text to $topic");
    } catch (e) {
      Util.logException(e.toString());
    }
  }

  void _setupSubscriptions() async {
    Util.logInfo('_setupSubscriptions called');

    _mqttClient.updates?.listen((List<MqttReceivedMessage<MqttMessage>> messages) {
      try {
        for (var mqttMessage in messages) {
          final MqttPublishMessage message = mqttMessage.payload as MqttPublishMessage;
          String payload = utf8.decode(MqttPublishPayload.bytesToStringAsString(message.payload.message).codeUnits);
          var topic = message.variableHeader?.topicName;

          if (topic!.endsWith(_clientId)) {
            Util.logInfo('message received');
            Util.logInfo('topic: $topic');
            Util.logInfo('mesage: $payload');

            var topicArray = topic.split('/');
            var messageType = topicArray[3];

            switch(messageType) {
              case 'session':
                _sessionMessageReceived(jsonDecode(payload));
                break;

              case 'status':
                _statusMessageReceived(jsonDecode(payload));
                break;

              case 'ranking':
                _rankingMessageReceived(jsonDecode(payload));
                break;

              case 'job':
                _jobMessageReceived(jsonDecode(payload));
                break;

              case 'job_del':
                _jobDeleteReceived(jsonDecode(payload));
                break;

              case 'sync_request':
                _syncRequestReceived(jsonDecode(payload));
                break;

              case "mssg":
                _messageMessageReceived(payload);
                break;

              default:
                Util.logInfo('Unknown topic: $messageType');
                break;
            }
          }
        }
      } catch(ex) {
        Util.logException(ex.toString());
      }
    });

    var topic = "$_fromServerTopic#";
    _mqttClient.subscribe(topic, MqttQos.exactlyOnce);
    Util.logInfo('subscribed to topic: $topic');

    MessageService().publish<ConnectionStatus>(Constants.messageTopicConnectionStatusChanged, arguments: ConnectionStatus(status: ConnectionStatusEnum.connected));
  }

  void _sessionMessageReceived(payloadData) async {
    connectionState = ConnectionStateEnum.connected;

    await _sendSyncMessage();

    var sessionStatusMessage = SessionStatus.fromJson(payloadData);

    await MyApp.isarInstance.writeTxn(() async {
      await MyApp.isarInstance.sessionStatus.clear();
      await MyApp.isarInstance.sessionStatus.put(sessionStatusMessage);
    });

    MessageService().publish<SessionStatusInfoUpdate>(Constants.messageTopicSessionStatusInfoUpdate, arguments: SessionStatusInfoUpdate(status: sessionStatusMessage));

    _startTrackTimer();
  }

  void _statusMessageReceived(payloadData) async {
    var statusMessage = Status.fromJson(payloadData);

    await MyApp.isarInstance.writeTxn(() async {
      await MyApp.isarInstance.status.clear();
      await MyApp.isarInstance.status.put(statusMessage);
    });

    MessageService().publish<StatusInfoUpdate>(Constants.messageTopicStatusInfoUpdated, arguments: StatusInfoUpdate(status: statusMessage));
  }

  void _rankingMessageReceived(List<dynamic> payloadData) async {
    for (var entry in payloadData) {
      var rank = Rank.fromJson(entry);

      await MyApp.isarInstance.writeTxn(() async {
        await MyApp.isarInstance.ranks.put(rank);
      });
    }


    MessageService().publish<RankingUpdated>(Constants.messageTopicRankingUpdated, arguments: RankingUpdated());
  }

  void _jobMessageReceived(payloadData) async {
    Job newJob = Job.fromJson(payloadData);

    MyApp.isarInstance.writeTxnSync(() async {
      MyApp.isarInstance.jobs.putSync(newJob);
    });

    if (newJob.state == Constants.stateAssigned) {
      if (newJob.global) {
        await Util.playMp3('aaa.mp3');
      } else {
        await Util.playMp3('job_received.mp3');
      }
    }

    MessageService().publish<JobReceivedMessage>(Constants.messageTopicJobReceived, arguments: JobReceivedMessage(job: newJob));
  }

  void _jobDeleteReceived(payloadData) async {
    var jobDelMessage = JobDelMessage.fromJson(payloadData);

    await MyApp.isarInstance.writeTxn(() async {
      await MyApp.isarInstance.jobs.delete(jobDelMessage.id);
    });

    MessageService().publish<JobDeletedMessage>(Constants.messageTopicJobDeleted, arguments: JobDeletedMessage(id: jobDelMessage.id));
  }

  void _syncRequestReceived(payloadData) async {
    Util.logInfo('_syncRequestReceived');

    _sendSyncMessage();
  }

  void _messageMessageReceived(payloadData) async {
    var newMessage = await Message.mergeFromJson(payloadData);

    await MyApp.isarInstance.writeTxn(() async {
      await MyApp.isarInstance.messages.put(newMessage);
    });

    await Util.playMp3('asbeep.mp3');

    MessageService().publish<MessageReceivedMessage>(Constants.messageTopicMessageReceived, arguments: MessageReceivedMessage(message: newMessage));
  }

  void _startReconnectTimer() {
    connectionState = ConnectionStateEnum.notConnected;

    if (!_disconnectInProgress) {
      Util.logInfo("_startReconnectTimer called");

      _reconnectDelay = min(_reconnectDelay + 1, 30);

      _reconnectTimer = Timer(Duration(seconds: _reconnectDelay), () {
        _processBootstrap();
      });
    }
  }

  void _cancelReconnectTimer() {
    if (_reconnectTimer != null && _reconnectTimer!.isActive) {
      _reconnectTimer!.cancel();
    }
  }

  void _clientDisconnected() {
    connectionState = ConnectionStateEnum.notConnected;

    _cancelTrackTimer();

    Util.logInfo("_clientDisconnected called");

    MessageService().publish<ConnectionStatus>(Constants.messageTopicConnectionStatusChanged, arguments: ConnectionStatus(status: ConnectionStatusEnum.notConnected));

    if (!_disconnectInProgress) {
      _startReconnectTimer();
    }
  }

  void _processBootstrap() async {
    try {
      String? responseText = "";

      var deviceObject = DeviceObject();
      deviceObject.manufacturer = "sven";
      deviceObject.model = "emulator";
      deviceObject.os = "hat es";
      deviceObject.osVer = "0.0";

      var handshakeMessage = BootstrapRequest();
      handshakeMessage.app = "sb";
      handshakeMessage.mqttClientId = await Util.getAppUuid();
      handshakeMessage.deviceObject = deviceObject;
      handshakeMessage.ver = 200;

      //var jsonMap = handshakeMessage.toJson();
      //var json = jsonEncode(jsonMap);
      var uri = "http://test-app-server.dns.army:8080/bootstrap";
      Util.logInfo("Bootstrap request: $uri");

      var response = await http.get(Uri.parse(uri));
      responseText = response.body;

      Util.logInfo("Bootstrap response: $responseText");

      var bootstrapResponse = BootstrapResponse.fromJson(jsonDecode(responseText));

      var brokerUriAndPortArray = bootstrapResponse.broker.replaceFirst("mqtt://", "").split(":");
      _brokerUri = brokerUriAndPortArray[0];
      _brokerPort = int.parse(brokerUriAndPortArray[1]);
      _clientId = bootstrapResponse.id;
      _fromServerTopic = bootstrapResponse.fromServer;
      _toServerTopic = bootstrapResponse.toServer;

      _connectToBroker();
    } catch (ex) {
      _startReconnectTimer();
    }
  }

  _initSession() {
    var startSessionMessage = StartSessionMessage();
    var jsonMap = startSessionMessage.toJson();
    var json = jsonEncode(jsonMap);
    publishText("session", json);
  }

  _sendSyncMessage() async
  {
    var jobs = await MyApp.isarInstance.jobs.filter().stateGreaterThan(-1).findAll();

    var answer = SyncJobsMessage();
    answer.utcUnixTime = DateTime.now().toUtc().millisecondsSinceEpoch ~/ 1000;
    answer.sync = SyncJobMessageSync();
    answer.sync.jobs = [];
    for (var job in jobs) {
      SyncJobMessageJob syncJob = SyncJobMessageJob();
      syncJob.state = job.state;
      syncJob.id = job.id;
      syncJob.ver = job.ver.toString();
      answer.sync.jobs.add(syncJob);
    }

    MqttCore.instance.publishText("sync", jsonEncode(answer.toJson()));
  }

  void _startTrackTimer() {
    _trackTimer ??= Timer.periodic(const Duration(seconds: 60), (Timer t) {
        var answer = MyApp.currentPosition;
        if (answer != null) {
          var trackMessage = TrackMessage();
          trackMessage.pos = TrackPosition();
          trackMessage.pos.time = answer.timestamp.toIso8601String();
          trackMessage.pos.lat = answer.latitude;
          trackMessage.pos.long = answer.longitude;
          trackMessage.pos.acc = answer.accuracy.toInt();

          publishText("track", jsonEncode(answer.toJson()));
        }
      });
  }

  void _cancelTrackTimer() {
    if (_trackTimer != null && _trackTimer!.isActive) {
      _trackTimer!.cancel();
      _trackTimer = null;
    }
  }
}