Editor: UI panels and GameObject updates

editor/src/Managers/SelectionManager.h

@@ -1,6 +1,7 @@
 #pragma once
 
-#include <unordered_set>
+#include <vector>
+#include <algorithm>
 
 #include <XCEngine/Core/Event.h>
 #include <XCEngine/Components/GameObject.h>
@@ -15,26 +16,65 @@ public:
         return instance;
     }
     
-    ::XCEngine::Components::GameObject* GetSelectedEntity() const { return m_selectedEntity; }
-    
     void SetSelectedEntity(::XCEngine::Components::GameObject* entity) {
-        m_selectedEntity = entity;
+        if (m_selectedEntities.empty()) {
+            m_selectedEntities.push_back(entity);
+        } else {
+            m_selectedEntities[0] = entity;
+            m_selectedEntities.resize(1);
+        }
         OnSelectionChanged.Invoke(entity ? entity->GetID() : 0);
     }
     
-    void ClearSelection() {
-        SetSelectedEntity(nullptr);
+    void SetSelectedEntities(const std::vector<::XCEngine::Components::GameObject*>& entities) {
+        m_selectedEntities = entities;
+        if (!entities.empty()) {
+            OnSelectionChanged.Invoke(entities.back()->GetID());
+        } else {
+            OnSelectionChanged.Invoke(0);
+        }
     }
     
+    void AddToSelection(::XCEngine::Components::GameObject* entity) {
+        if (entity && !IsSelected(entity)) {
+            m_selectedEntities.push_back(entity);
+            OnSelectionChanged.Invoke(entity->GetID());
+        }
+    }
+    
+    void RemoveFromSelection(::XCEngine::Components::GameObject* entity) {
+        auto it = std::find(m_selectedEntities.begin(), m_selectedEntities.end(), entity);
+        if (it != m_selectedEntities.end()) {
+            m_selectedEntities.erase(it);
+            OnSelectionChanged.Invoke(entity ? entity->GetID() : 0);
+        }
+    }
+    
+    void ClearSelection() {
+        m_selectedEntities.clear();
+        OnSelectionChanged.Invoke(0);
+    }
+    
+    ::XCEngine::Components::GameObject* GetSelectedEntity() const {
+        return m_selectedEntities.empty() ? nullptr : m_selectedEntities.back();
+    }
+    
+    const std::vector<::XCEngine::Components::GameObject*>& GetSelectedEntities() const {
+        return m_selectedEntities;
+    }
+    
+    bool HasSelection() const { return !m_selectedEntities.empty(); }
+    size_t GetSelectionCount() const { return m_selectedEntities.size(); }
+    
     bool IsSelected(::XCEngine::Components::GameObject* entity) const {
-        return m_selectedEntity == entity;
+        return std::find(m_selectedEntities.begin(), m_selectedEntities.end(), entity) != m_selectedEntities.end();
     }
     
     ::XCEngine::Core::Event<uint64_t> OnSelectionChanged;
     
 private:
     SelectionManager() = default;
-    ::XCEngine::Components::GameObject* m_selectedEntity = nullptr;
+    std::vector<::XCEngine::Components::GameObject*> m_selectedEntities;
 };
 
 }