tablet-app/lib/Helpers/MQTTHelper.dart

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:managerapi/api.dart';
import 'package:mqtt_client/mqtt_client.dart';
import 'package:mqtt_client/mqtt_server_client.dart';
import 'package:tablet_app/Models/tabletContext.dart';
import 'package:unique_identifier/unique_identifier.dart';

import 'DatabaseHelper.dart';

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

  void onConnected(dynamic appContext) {
    print('Connected !!!!!!!!!!!! ----------------------------------');
    TabletAppContext tabletAppContext = appContext.getContext();
    tabletAppContext.clientMQTT.updates.listen((List<MqttReceivedMessage<MqttMessage>> c) {
      final MqttPublishMessage message = c[0].payload;
      final payload = MqttPublishPayload.bytesToStringAsString(message.payload.message);
      print('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');
          var configId = c[0].topic.split('/')[1];
          if (configId != null) {
            // Check if tablet config
            if (tabletAppContext.configuration.id == configId) {
              // refresh config
              try {
                PlayerMessageDTO playerMessage = PlayerMessageDTO.fromJson(jsonDecode(payload));
                var isConfigChanged = playerMessage.configChanged != null ? playerMessage.configChanged : false;
                if (isConfigChanged) {
                  updateConfig(appContext);
                }
              }
              catch(e) {
                print('Error = $e');
              }
            }
          }
          break;
        case "player":
          print('Get message in topic player = $payload');

          // refresh device info
          try {
            PlayerMessageDTO playerMessage = PlayerMessageDTO.fromJson(jsonDecode(payload));
            var isConfigChanged = playerMessage.configChanged != null ? playerMessage.configChanged : false;
            if (isConfigChanged) {
              updateDevice(appContext);
            }
          }
          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 {
    TabletAppContext tabletAppContext = appContext.getContext();

    var identifier = await UniqueIdentifier.serial;
    tabletAppContext.clientMQTT = MqttServerClient.withPort(tabletAppContext.host.replaceAll('http://', ''), 'tablet_app_'+identifier, 1883);
    isInstantiated = true;

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

    var message = {
      "deviceId": tabletAppContext.deviceId != null ? tabletAppContext.deviceId : identifier,
      "connected": false
    };

    final connMessage = MqttConnectMessage().authenticateAs('admin', 'mdlf2021!') // TODO ONLINE
        .keepAliveFor(60)
        .withWillTopic('player/status')
        .withWillMessage(jsonEncode(message))
        .withClientIdentifier('tablet_app_'+identifier)
        .startClean()
        .withWillQos(MqttQos.atLeastOnce);

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

      // For get config changed request
      if(tabletAppContext.configuration != null) {
        tabletAppContext.clientMQTT.subscribe('config/#', MqttQos.atLeastOnce);
      }

      // For get device assignation config request
      if(tabletAppContext.deviceId != null) {
        tabletAppContext.clientMQTT.subscribe('player/${tabletAppContext.deviceId}', MqttQos.atLeastOnce);

        var message = {
          "deviceId": tabletAppContext.deviceId,
          "connected": true
        };

        const pubTopic = 'player/status';
        final builder = MqttClientPayloadBuilder();

        builder.addString(jsonEncode(message));
        tabletAppContext.clientMQTT.publishMessage(pubTopic, MqttQos.atLeastOnce, builder.payload);
      }
    } catch (e) {
      print('Exception: $e');
      tabletAppContext.clientMQTT.disconnect();
    }

    return tabletAppContext.clientMQTT;
  }

  Future<void> updateDevice(dynamic appContext) async {
    print("updateDevice");

    TabletAppContext tabletAppContext = appContext.getContext();
    DeviceDetailDTO device = await tabletAppContext.clientAPI.deviceApi.deviceGetDetail(tabletAppContext.deviceId);

    print(device);

    if (device != null) {
      // STORE IT LOCALLY !!
      TabletAppContext tabletAppContext = appContext.getContext();
      tabletAppContext.deviceId = device.id;
      tabletAppContext.configuration.id = device.configurationId;

      appContext.setContext(tabletAppContext);

      // STORE IT LOCALLY (SQLite)
      await DatabaseHelper.instance.update(tabletAppContext);

      Fluttertoast.showToast(
          msg: "La tablette a bien été mise à jour",
          toastLength: Toast.LENGTH_SHORT,
          gravity: ToastGravity.BOTTOM,
          timeInSecForIosWeb: 1,
          backgroundColor: Colors.lightGreen,
          textColor: Colors.white,
          fontSize: 16.0
      );
    } else {
      Fluttertoast.showToast(
          msg: "Une erreur est survenue lors de la mise à jour de la tablette",
          toastLength: Toast.LENGTH_SHORT,
          gravity: ToastGravity.BOTTOM,
          timeInSecForIosWeb: 1,
          backgroundColor:  Colors.deepOrangeAccent,
          textColor: Colors.white,
          fontSize: 16.0
      );
    }
  }

  void updateConfig(appContext) async {
    print("update config");

    TabletAppContext tabletAppContext = appContext.getContext();
    ConfigurationDTO configuration = await tabletAppContext.clientAPI.configurationApi.configurationGetDetail(tabletAppContext.configuration.id);

    if (configuration != null) {
      // STORE IT LOCALLY !!
      TabletAppContext tabletAppContext = appContext.getContext();
      tabletAppContext.configuration = configuration;

      if(!configuration.languages.contains(tabletAppContext.language)) {
        tabletAppContext.language = configuration.languages[0];
      }

      appContext.setContext(tabletAppContext);

      // STORE IT LOCALLY (SQLite)
      await DatabaseHelper.instance.update(tabletAppContext);

      Fluttertoast.showToast(
          msg: "La configuration a bien été mise à jour",
          toastLength: Toast.LENGTH_SHORT,
          gravity: ToastGravity.BOTTOM,
          timeInSecForIosWeb: 1,
          backgroundColor: Colors.lightGreen,
          textColor: Colors.white,
          fontSize: 16.0
      );
    } else {
      Fluttertoast.showToast(
          msg: "Une erreur est survenue lors de la mise à jour de la configuration",
          toastLength: Toast.LENGTH_SHORT,
          gravity: ToastGravity.BOTTOM,
          timeInSecForIosWeb: 1,
          backgroundColor:  Colors.deepOrangeAccent,
          textColor: Colors.white,
          fontSize: 16.0
      );
    }
  }
}