replace combined stateUpdated signal with individual events

src/ui/MainWindow.h

@@ -5,7 +5,9 @@
 
 #include <QWidget>
 
+#include "BuildingBlocksChangedEvent.h"
 #include "BuildingId.h"
+#include "EventHandler.h"
 #include "ShipLayoutBlueprint.h"
 #include "Tick.h"
 #include "VisualsConfig.h"
@@ -19,26 +21,29 @@ class BlueprintPanel;
 class QCloseEvent;
 class QResizeEvent;
 
-class MainWindow : public QWidget
+class MainWindow : public QWidget,
+                   public EventHandler<BuildingBlocksChangedEvent>
 {
     Q_OBJECT
 
 public:
     MainWindow(Simulation* sim, const std::string& configDir, QWidget* parent = nullptr);
+    ~MainWindow() override;
 
 protected:
     void resizeEvent(QResizeEvent* event) override;
     void closeEvent(QCloseEvent* event) override;
 
+private:
+    void handleEvent(std::shared_ptr<const BuildingBlocksChangedEvent> event) override;
+    void layoutPanels();
+
 private slots:
     void onGameOver();
-    void onStateUpdated(Tick tick, int blocks, double speed);
     void onEscapeMenuRequested();
     void onLayoutDialogRequested(BuildingId shipyardId);
 
 private:
-    void layoutPanels();
-
     std::string            m_configDir;
     VisualsConfig          m_visuals;
     Simulation*            m_sim;