myhomie_app/lib/Helpers/MQTTHelper.dart

import 'dart:convert';

import 'package:fluttertoast/fluttertoast.dart';
import 'package:mqtt_client/mqtt_client.dart';
import 'package:mqtt_client/mqtt_server_client.dart';
import 'package:myhomie_app/Models/homieContext.dart';
import 'package:myhomie_app/app_context.dart';


class MQTTHelper {
  MQTTHelper._privateConstructor();
  bool isInstantiated = false;
  static final MQTTHelper instance = MQTTHelper._privateConstructor();

  void onConnected(AppContext appContext) {
    print('Connected !!!!!!!!!!!! ----------------------------------');
    HomieAppContext homieAppContext = appContext.getContext();

    homieAppContext.clientMQTT.subscribe("#", MqttQos.atLeastOnce);

    print(homieAppContext.clientMQTT);

    homieAppContext.clientMQTT.updates.listen((List<MqttReceivedMessage<MqttMessage>> c) async {
      print("IN Received message");
      final MqttPublishMessage message = c[0].payload;
      final payload = MqttPublishPayload.bytesToStringAsString(message.payload.message);
      print('Received message:$payload from topic: ${c[0].topic}');

      appContext.setLastMessage('Received message:$payload from topic: ${c[0].topic}');

      var topic = c[0].topic.split('/')[0];

      switch(topic) {
        case "config":
          print('Get message in topic config = $payload');
          break;
        case "player":
          print('Get message in topic player = $payload');
          // refresh device info
          try {
          }
          catch(e) {
            print('Error = $e');
          }
          break;
      }
    });
  }

  // unconnected
  void onDisconnected() {
    print('Disconnected');
  }

  // subscribe to topic succeeded
  void onSubscribed(String topic) {
    print('Subscribed topic: $topic');
  }

  // subscribe to topic failed
  void onSubscribeFail(String topic) {
    print('Failed to subscribe $topic');
  }

  // unsubscribe succeeded
  void onUnsubscribed(String topic) {
    print('Unsubscribed topic: $topic');
  }

  Future<MqttServerClient> connect(dynamic appContext) async {
    HomieAppContext homieAppContext = appContext.getContext();

    if (homieAppContext == null) {
      homieAppContext = new HomieAppContext(host: '192.168.31.140', userId: 'TODO');
    } // TO DEBUG

    if(homieAppContext.host != null) {
      homieAppContext.clientMQTT = MqttServerClient.withPort(homieAppContext.host.replaceAll('http://', ''), 'homie_app_'+homieAppContext.userId, 1883);
      isInstantiated = true;

      homieAppContext.clientMQTT.logging(on: false);
      homieAppContext.clientMQTT.keepAlivePeriod = 20;
      homieAppContext.clientMQTT.onDisconnected = onDisconnected;
      homieAppContext.clientMQTT.onConnected = () => onConnected(appContext);
      homieAppContext.clientMQTT.onSubscribed = onSubscribed;

      var message = {
        "userId": homieAppContext.userId,
        "connected": false
      };

      final connMessage = MqttConnectMessage().authenticateAs('user', 'user') // TODO ONLINE
          .keepAliveFor(60)
          .withWillTopic('player/status')
          .withWillMessage(jsonEncode(message))
          .withClientIdentifier('tablet_app_'+homieAppContext.userId)
          .startClean()
          .withWillQos(MqttQos.atLeastOnce);

      homieAppContext.clientMQTT.connectionMessage = connMessage;
      homieAppContext.clientMQTT.autoReconnect = true;
      try {
        await homieAppContext.clientMQTT.connect();

      } catch (e) {
        print('Exception: $e');
        homieAppContext.clientMQTT.disconnect();
      }
      appContext.setContext(homieAppContext); // TODO CLEAN

      return homieAppContext.clientMQTT;
    }
    return null;
  }
}