add mqtt control

src/mqttcontroller.h

@@ -0,0 +1,42 @@
+#ifndef MQTTCONTROLLER_H
+#define MQTTCONTROLLER_H
+
+#include <QObject>
+#include <QString>
+
+#include "appconfig.h"
+
+struct mosquitto;
+struct mosquitto_message;
+
+class MqttController : public QObject
+{
+  Q_OBJECT
+public:
+  explicit MqttController(const MqttConfig &config, QObject *parent = nullptr);
+  ~MqttController();
+
+  void start();
+
+signals:
+  void play();
+  void pause();
+  void nextImage();
+  void nextFolder();
+  void restart();
+
+private slots:
+  void handleCommand(const QString &payload);
+
+private:
+  static void HandleConnect(struct mosquitto *mosq, void *userdata, int rc);
+  static void HandleMessage(struct mosquitto *mosq, void *userdata, const struct mosquitto_message *message);
+
+  void subscribe();
+
+  MqttConfig config;
+  struct mosquitto *client = nullptr;
+  bool connected = false;
+};
+
+#endif // MQTTCONTROLLER_H