Rework Mqtt Implementation

api/src/main/java/be/naaturel/boardmateapi/services/MqttService.java

@@ -2,59 +2,110 @@ package be.naaturel.boardmateapi.services;
 
 import be.naaturel.boardmateapi.common.exceptions.ServiceException;
 import be.naaturel.boardmateapi.common.helpers.Logger;
+import be.naaturel.boardmateapi.common.models.MqttMessageWrapper;
 import org.eclipse.paho.client.mqttv3.*;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Service;
 
+import java.nio.charset.StandardCharsets;
+import java.util.function.Consumer;
+
 @Service
 public class MqttService {
 
     private final MqttClient publisher;
     private final MqttClient subscriber;
+    private Consumer<Throwable> onConnectionLost;
+    private Consumer<MqttMessageWrapper> onMessageReceived;
 
     public MqttService(
             @Qualifier("mqttPublisher") MqttClient publisher,
             @Qualifier("mqttSubscriber") MqttClient subscriber
-            ) {
+    ) {
         this.publisher = publisher;
         this.subscriber = subscriber;
+        this.onConnectionLost = null;
+        this.onMessageReceived = null;
     }
 
-    public void publish(String topic, String payload) throws ServiceException {
+    public void onConnectionLost(Consumer<Throwable> consumer){
+        this.onConnectionLost = consumer;
+    }
+
+    public void onMessageReceived(Consumer<MqttMessageWrapper> consumer){
+        this.onMessageReceived = consumer;
+    }
+
+    public void disconnect() {
         try {
-            MqttMessage message = new MqttMessage(payload.getBytes());
-            message.setQos(1);
-            if(!publisher.isConnected()){
-                publisher.connect();
-            }
-            publisher.publish(topic, message);
-            Logger.displayInfo("Published message: " + payload);
-        } catch (MqttException e) {
-            throw new ServiceException("Unable to publish message", e);
-        } finally {
-            try{
-                if (publisher.isConnected()) publisher.disconnect();
-            } catch (MqttException e){
-                Logger.displayError("Failed to disconnect MQTT client: " + e.getMessage());
-            }
+            disconnect(publisher);
+            disconnect(subscriber);
+        } catch (ServiceException e) {
+            Logger.displayError("Failed to disconnect MQTT client" + e.getMessage());
         }
     }
 
-    public void subscribe(String topic) throws ServiceException {
+    public void publish(String topic, String payload) {
+        try {
+            connect(publisher, null);
+            MqttMessage message = new MqttMessage(payload.getBytes(StandardCharsets.UTF_8));
+            message.setQos(1);
+            publisher.publish(topic, message);
+        } catch (MqttException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public void subscribe(String topic) {
         try {
             MqttConnectOptions options = new MqttConnectOptions();
             options.setAutomaticReconnect(true);
-            options.setCleanSession(true);
+            options.setCleanSession(false);
+
+            connect(subscriber, options);
 
-            if(!subscriber.isConnected()){
-                subscriber.connect(options);
-            }
             subscriber.subscribe(topic, 1);
-            Logger.displayInfo("Subscribed to topic: " + topic);
-
         } catch (MqttException e) {
-            throw new ServiceException("Unable to subscribe", e);
+            throw new RuntimeException(e);
         }
     }
 
+    public void registerCallback(){
+        this.subscriber.setCallback(new MqttCallback() {
+            @Override
+            public void connectionLost(Throwable cause) {
+                onConnectionLost.accept(cause);
+            }
+
+            @Override
+            public void messageArrived(String topic, MqttMessage message) {
+                MqttMessageWrapper msg = new MqttMessageWrapper(topic, message);
+                onMessageReceived.accept(msg);
+            }
+
+            @Override
+            public void deliveryComplete(IMqttDeliveryToken token) {
+                // Not needed for subscriber
+            }
+        });
+    }
+
+    private void disconnect(MqttClient client) throws ServiceException {
+        if(client.isConnected()){
+            try {
+                client.disconnect();
+            } catch (MqttException e) {
+                throw new ServiceException("Failed to disconnect the broker", e);
+            }
+        }
+    }
+
+    private void connect(MqttClient client, MqttConnectOptions options) throws MqttException {
+        if (client.isConnected()) return;
+        if (options == null) {
+            client.connect();
+        } else {
+            client.connect(options);
+        }
+    }
 }