make bluetooth service singleton

include/services/bluetooth.hpp

@@ -2,14 +2,17 @@
 
 #include <gio/gio.h>
 #include <gtk/gtk.h>
+#include <string>
+#include <vector>
 
 #include "sigc++/signal.h"
 
 class BluetoothService {
+  static BluetoothService *instance;
+  
   public:
-    BluetoothService();
-
     sigc::signal<void(bool)> powerStateChangedSignal;
+
     sigc::signal<void(bool)> isDiscoveringChangedSignal;
 
     bool getPowerState();
@@ -19,10 +22,22 @@ class BluetoothService {
     void togglePowerState();
     void toggleIsDiscovering();
 
-private:
+    static BluetoothService *getInstance() {
+        if (BluetoothService::instance == nullptr) {
+
+            BluetoothService::instance = new BluetoothService();
+        }
+        return BluetoothService::instance;
+    }
+
+  private:
+    BluetoothService();
+
     GDBusProxy *adapter_proxy = nullptr;
-    bool powerState           = false;
-    bool isDiscovering        = false;
+
+    std::vector<std::string> getDeviceObjectPaths();
+    bool powerState    = false;
+    bool isDiscovering = false;
 
     void onPropertyChanged(GDBusProxy *proxy,
                            GVariant *changed_properties,