replace combined stateUpdated signal with individual events

src/ui/BlueprintPanel.h

@@ -5,7 +5,9 @@
 #include <QWidget>
 
 #include "Blueprint.h"
+#include "BuildingBlocksChangedEvent.h"
 #include "BuildingId.h"
+#include "EventHandler.h"
 #include "GameConfig.h"
 #include "Tick.h"
 
@@ -14,22 +16,26 @@ class QPushButton;
 class QScrollArea;
 class QVBoxLayout;
 
-class BlueprintPanel : public QWidget
+class BlueprintPanel : public QWidget,
+                       public EventHandler<BuildingBlocksChangedEvent>
 {
     Q_OBJECT
 
 public:
     BlueprintPanel(Simulation* sim, const GameConfig* config, QWidget* parent = nullptr);
+    ~BlueprintPanel() override;
 
 public slots:
     void onSelectionChanged(const std::vector<BuildingId>& ids);
-    void onStateUpdated(Tick tick, int blocks, double speed);
     void clearActiveBlueprintButton();
 
 signals:
     void blueprintPlacementRequested(Blueprint blueprint);
     void exitBlueprintModeRequested();
 
+private:
+    void handleEvent(std::shared_ptr<const BuildingBlocksChangedEvent> event) override;
+
 private slots:
     void onCreateClicked();
     void onDeleteBlueprintClicked(int index);