feat: add "Add component" button

destrum/src/Util/ImGuiUtils.cpp

@@ -2,6 +2,7 @@
 
 #include <algorithm>
 #include <cfloat>
+#include <exception>
 #include <string>
 #include <unordered_set>
 #include <vector>
@@ -14,6 +15,8 @@
 #include <destrum/ObjectModel/Component.h>
 #include <destrum/ObjectModel/GameObject.h>
 #include <destrum/ObjectModel/Transform.h>
+#include <destrum/Serialization/ComponentFactory.h>
+#include <destrum/Serialization/ComponentRegistry.h>
 
 namespace {
     [[nodiscard]] bool IsInspectableObject(const GameObject* object) {
@@ -121,6 +124,8 @@ namespace ImGuiUtils {
         const std::vector<std::shared_ptr<GameObject>>& objectsSource,
         const std::vector<std::shared_ptr<GameObject>>& pendingAdditions,
         ObjectId& selectedObjectId) {
+        RegisterEngineComponents();
+
         std::vector<GameObject*> objects;
         objects.reserve(objectsSource.size() + pendingAdditions.size());
 
@@ -268,9 +273,69 @@ namespace ImGuiUtils {
                         worldPosition.z);
                 }
 
-                if (ImGui::CollapsingHeader(
-                        "Components",
-                        ImGuiTreeNodeFlags_DefaultOpen)) {
+                const bool componentsOpen = ImGui::CollapsingHeader(
+                    "Components",
+                    ImGuiTreeNodeFlags_DefaultOpen);
+
+                if (componentsOpen) {
+                    if (ImGui::Button("+ Add Component")) {
+                        ImGui::OpenPopup("AddComponentPopup");
+                    }
+
+                    std::string addComponentError;
+                    if (ImGui::BeginPopup("AddComponentPopup")) {
+                        std::vector<std::string> componentTypes =
+                            ComponentFactory::GetRegisteredTypeNames();
+                        std::sort(componentTypes.begin(), componentTypes.end());
+
+                        bool hasAvailableComponent = false;
+                        for (const std::string& componentType : componentTypes) {
+                            const bool alreadyAdded = std::any_of(
+                                selectedObject->GetComponents().begin(),
+                                selectedObject->GetComponents().end(),
+                                [&componentType](const auto& component) {
+                                    return component != nullptr &&
+                                           !component->IsBeingDestroyed() &&
+                                           component->GetTypeName() == componentType;
+                                });
+
+                            if (alreadyAdded) {
+                                const std::string label =
+                                    componentType + " (already added)";
+                                ImGui::BeginDisabled();
+                                ImGui::MenuItem(label.c_str());
+                                ImGui::EndDisabled();
+                                continue;
+                            }
+
+                            hasAvailableComponent = true;
+                            if (ImGui::MenuItem(componentType.c_str())) {
+                                try {
+                                    if (ComponentFactory::Create(
+                                            componentType,
+                                            *selectedObject) == nullptr) {
+                                        addComponentError =
+                                            "Component type is not registered: " +
+                                            componentType;
+                                    } else {
+                                        ImGui::CloseCurrentPopup();
+                                    }
+                                } catch (const std::exception& exception) {
+                                    addComponentError = exception.what();
+                                }
+                            }
+                        }
+
+                        if (!hasAvailableComponent) {
+                            ImGui::TextDisabled("All components are already added.");
+                        }
+                        if (!addComponentError.empty()) {
+                            ImGui::TextWrapped("Failed to add component: %s",
+                                               addComponentError.c_str());
+                        }
+                        ImGui::EndPopup();
+                    }
+
                     bool hasComponents = false;
                     for (const auto& component : selectedObject->GetComponents()) {
                         if (component == nullptr || component->IsBeingDestroyed()) {