XCEngine/new_editor/app/Scene/EditorSceneRuntime.cpp

#include "Scene/EditorSceneRuntime.h"

#include <XCEngine/Components/CameraComponent.h>
#include <XCEngine/Components/Component.h>
#include <XCEngine/Components/GameObject.h>
#include <XCEngine/Components/TransformComponent.h>
#include <XCEngine/Scene/Scene.h>

#include <charconv>
#include <cmath>
#include <unordered_map>

namespace XCEngine::UI::Editor::App {

namespace {

using ::XCEngine::Components::GameObject;
using ::XCEngine::Components::Scene;
using ::XCEngine::Components::TransformComponent;
using ::XCEngine::Components::Component;
using ::XCEngine::Math::Quaternion;
using ::XCEngine::Math::Vector3;

constexpr char kComponentIdSeparator = '#';

std::string ResolveGameObjectDisplayName(const GameObject& gameObject) {
    return gameObject.GetName().empty()
        ? std::string("GameObject")
        : gameObject.GetName();
}

bool NearlyEqual(float lhs, float rhs, float epsilon = 0.0001f) {
    return std::abs(lhs - rhs) <= epsilon;
}

bool NearlyEqual(const Vector3& lhs, const Vector3& rhs, float epsilon = 0.0001f) {
    return NearlyEqual(lhs.x, rhs.x, epsilon) &&
        NearlyEqual(lhs.y, rhs.y, epsilon) &&
        NearlyEqual(lhs.z, rhs.z, epsilon);
}

bool NearlyEqual(const Quaternion& lhs, const Quaternion& rhs, float epsilon = 0.0001f) {
    return std::abs(lhs.Dot(rhs)) >= 1.0f - epsilon;
}

bool TransformSnapshotsMatch(
    const SceneTransformSnapshot& lhs,
    const SceneTransformSnapshot& rhs) {
    return lhs.IsValid() &&
        rhs.IsValid() &&
        lhs.targetId == rhs.targetId &&
        NearlyEqual(lhs.position, rhs.position) &&
        NearlyEqual(lhs.rotation, rhs.rotation) &&
        NearlyEqual(lhs.scale, rhs.scale);
}

std::string BuildEditorComponentId(
    std::string_view typeName,
    std::size_t ordinal) {
    std::string componentId(typeName);
    componentId.push_back(kComponentIdSeparator);
    componentId += std::to_string(ordinal);
    return componentId;
}

bool ParseEditorComponentId(
    std::string_view componentId,
    std::string& outTypeName,
    std::size_t& outOrdinal) {
    const std::size_t separatorIndex = componentId.find(kComponentIdSeparator);
    if (separatorIndex == std::string_view::npos ||
        separatorIndex == 0u ||
        separatorIndex + 1u >= componentId.size()) {
        return false;
    }

    outTypeName = std::string(componentId.substr(0u, separatorIndex));
    std::size_t ordinal = 0u;
    const std::string_view ordinalText =
        componentId.substr(separatorIndex + 1u);
    const char* first = ordinalText.data();
    const char* last = ordinalText.data() + ordinalText.size();
    const std::from_chars_result result =
        std::from_chars(first, last, ordinal);
    if (result.ec != std::errc() || result.ptr != last) {
        outTypeName.clear();
        return false;
    }

    outOrdinal = ordinal;
    return true;
}

EditorSceneComponentDescriptor BuildComponentDescriptor(
    const Component& component,
    std::size_t ordinal) {
    EditorSceneComponentDescriptor descriptor = {};
    descriptor.typeName = component.GetName();
    descriptor.componentId =
        BuildEditorComponentId(descriptor.typeName, ordinal);
    descriptor.component = &component;
    descriptor.removable =
        component.GetGameObject() != nullptr &&
        component.GetGameObject()->GetTransform() != &component;
    return descriptor;
}

} // namespace

std::string_view GetSceneToolModeName(SceneToolMode mode) {
    switch (mode) {
    case SceneToolMode::View:
        return "View";
    case SceneToolMode::Translate:
        return "Move";
    case SceneToolMode::Rotate:
        return "Rotate";
    case SceneToolMode::Scale:
        return "Scale";
    case SceneToolMode::Transform:
        return "Transform";
    default:
        return "Unknown";
    }
}

std::string_view GetSceneToolSpaceModeName(SceneToolSpaceMode mode) {
    switch (mode) {
    case SceneToolSpaceMode::World:
        return "World";
    case SceneToolSpaceMode::Local:
        return "Local";
    default:
        return "Unknown";
    }
}

std::string_view GetSceneToolPivotModeName(SceneToolPivotMode mode) {
    switch (mode) {
    case SceneToolPivotMode::Pivot:
        return "Pivot";
    case SceneToolPivotMode::Center:
        return "Center";
    default:
        return "Unknown";
    }
}

std::string_view GetSceneToolHandleName(SceneToolHandle handle) {
    switch (handle) {
    case SceneToolHandle::AxisX:
        return "AxisX";
    case SceneToolHandle::AxisY:
        return "AxisY";
    case SceneToolHandle::AxisZ:
        return "AxisZ";
    case SceneToolHandle::None:
    default:
        return "None";
    }
}

std::string_view GetSceneToolInteractionLockName(SceneToolInteractionLock lock) {
    switch (lock) {
    case SceneToolInteractionLock::TransformDrag:
        return "TransformDrag";
    case SceneToolInteractionLock::None:
    default:
        return "None";
    }
}

bool EditorSceneRuntime::Initialize(const std::filesystem::path& projectRoot) {
    m_projectRoot = projectRoot;
    m_ownedSelectionService = {};
    m_selectionService = &m_ownedSelectionService;
    m_startupSceneResult = EnsureEditorStartupScene(projectRoot);
    EnsureSceneViewCamera();
    ResetTransformEditHistory();
    m_toolState = {};
    RefreshScene();
    return m_startupSceneResult.ready;
}

void EditorSceneRuntime::BindSelectionService(
    EditorSelectionService* selectionService) {
    m_selectionService =
        selectionService != nullptr ? selectionService : &m_ownedSelectionService;
}

void EditorSceneRuntime::RefreshScene() {
    if (HasHierarchySelection()) {
        if (!HasValidSelection()) {
            ClearSelection();
        } else {
            RevalidateSelection();
        }
    } else if (m_toolState.dragState.active) {
        ResetToolInteractionState();
    }

    ClearInvalidToolInteractionState();
}

void EditorSceneRuntime::EnsureSceneSelection() {
    if (HasValidSelection() ||
        SelectionService().HasSelectionKind(EditorSelectionKind::ProjectItem)) {
        return;
    }

    SelectFirstAvailableGameObject();
}

const EditorStartupSceneResult& EditorSceneRuntime::GetStartupResult() const {
    return m_startupSceneResult;
}

Scene* EditorSceneRuntime::GetActiveScene() const {
    return GetActiveEditorScene();
}

::XCEngine::Components::CameraComponent* EditorSceneRuntime::GetSceneViewCamera() {
    return EnsureSceneViewCamera() ? m_sceneViewCamera.camera : nullptr;
}

const ::XCEngine::Components::CameraComponent* EditorSceneRuntime::GetSceneViewCamera() const {
    return m_sceneViewCamera.camera;
}

float EditorSceneRuntime::GetSceneViewOrbitDistance() const {
    return m_sceneViewCamera.controller.GetDistance();
}

SceneViewportRenderRequest EditorSceneRuntime::BuildSceneViewportRenderRequest() {
    SceneViewportRenderRequest request = {};
    request.scene = GetActiveScene();
    request.camera = GetSceneViewCamera();
    request.orbitDistance = GetSceneViewOrbitDistance();
    if (const std::optional<GameObject::ID> selectedId = GetSelectedGameObjectId();
        selectedId.has_value()) {
        request.selectedObjectIds.push_back(selectedId.value());
    }
    return request;
}

void EditorSceneRuntime::ApplySceneViewportCameraInput(
    const SceneViewportCameraInputState& input) {
    if (!EnsureSceneViewCamera()) {
        return;
    }

    m_sceneViewCamera.controller.ApplyInput(input);
    ApplySceneViewCameraController();
}

bool EditorSceneRuntime::FocusSceneSelection() {
    const GameObject* selectedGameObject = GetSelectedGameObject();
    if (selectedGameObject == nullptr || !EnsureSceneViewCamera()) {
        return false;
    }

    const auto* transform = selectedGameObject->GetTransform();
    if (transform == nullptr) {
        return false;
    }

    m_sceneViewCamera.controller.Focus(transform->GetPosition());
    ApplySceneViewCameraController();
    return true;
}

bool EditorSceneRuntime::HasSceneSelection() const {
    return HasValidSelection();
}

std::optional<GameObject::ID> EditorSceneRuntime::GetSelectedGameObjectId() const {
    if (!HasHierarchySelection()) {
        return std::nullopt;
    }

    return ParseEditorGameObjectItemId(SelectionService().GetSelection().itemId);
}

std::string EditorSceneRuntime::GetSelectedItemId() const {
    const std::optional<GameObject::ID> selectedId = GetSelectedGameObjectId();
    return selectedId.has_value()
        ? MakeEditorGameObjectItemId(selectedId.value())
        : std::string();
}

std::string EditorSceneRuntime::GetSelectedDisplayName() const {
    const GameObject* gameObject = GetSelectedGameObject();
    return gameObject != nullptr
        ? ResolveGameObjectDisplayName(*gameObject)
        : std::string();
}

const GameObject* EditorSceneRuntime::GetSelectedGameObject() const {
    const std::optional<GameObject::ID> selectedId = GetSelectedGameObjectId();
    if (!selectedId.has_value()) {
        return nullptr;
    }

    Scene* scene = GetActiveScene();
    return scene != nullptr ? scene->FindByID(selectedId.value()) : nullptr;
}

std::vector<EditorSceneComponentDescriptor> EditorSceneRuntime::GetSelectedComponents() const {
    std::vector<EditorSceneComponentDescriptor> descriptors = {};
    const GameObject* gameObject = GetSelectedGameObject();
    if (gameObject == nullptr) {
        return descriptors;
    }

    const std::vector<const Component*> components =
        gameObject->GetComponents<Component>();
    descriptors.reserve(components.size());
    std::unordered_map<std::string, std::size_t> ordinalsByType = {};
    for (const Component* component : components) {
        if (component == nullptr) {
            continue;
        }

        const std::string typeName = component->GetName();
        const std::size_t ordinal = ordinalsByType[typeName];
        descriptors.push_back(BuildComponentDescriptor(*component, ordinal));
        ordinalsByType[typeName] = ordinal + 1u;
    }

    return descriptors;
}

std::uint64_t EditorSceneRuntime::GetSelectionStamp() const {
    return SelectionService().GetStamp();
}

bool EditorSceneRuntime::SetSelection(std::string_view itemId) {
    const std::optional<GameObject::ID> gameObjectId =
        ParseEditorGameObjectItemId(itemId);
    if (!gameObjectId.has_value()) {
        return false;
    }

    return SetSelection(gameObjectId.value());
}

bool EditorSceneRuntime::SetSelection(GameObject::ID id) {
    if (id == GameObject::INVALID_ID) {
        return false;
    }

    Scene* scene = GetActiveScene();
    GameObject* gameObject = scene != nullptr ? scene->FindByID(id) : nullptr;
    if (gameObject == nullptr) {
        return false;
    }

    const std::optional<GameObject::ID> previousId = GetSelectedGameObjectId();
    const bool changed =
        !previousId.has_value() ||
        previousId.value() != id ||
        !HasHierarchySelection();
    if (changed) {
        ResetToolInteractionState();
    }
    SelectionService().SetHierarchySelection(
        MakeEditorGameObjectItemId(id),
        ResolveGameObjectDisplayName(*gameObject));
    ClearInvalidToolInteractionState();
    return changed;
}

void EditorSceneRuntime::ClearSelection() {
    ResetToolInteractionState();
    SelectionService().ClearSelection();
}

bool EditorSceneRuntime::OpenSceneAsset(const std::filesystem::path& scenePath) {
    if (!OpenEditorSceneAsset(scenePath)) {
        return false;
    }

    m_startupSceneResult.ready = true;
    m_startupSceneResult.loadedFromDisk = true;
    m_startupSceneResult.scenePath = scenePath;
    if (Scene* activeScene = GetActiveScene();
        activeScene != nullptr) {
        m_startupSceneResult.sceneName = activeScene->GetName();
    } else {
        m_startupSceneResult.sceneName = scenePath.stem().string();
    }

    ResetTransformEditHistory();
    ResetToolInteractionState();
    SelectionService().ClearSelection();
    RefreshScene();
    EnsureSceneSelection();
    return true;
}

GameObject* EditorSceneRuntime::FindGameObject(std::string_view itemId) const {
    return FindEditorGameObject(itemId);
}

bool EditorSceneRuntime::RenameGameObject(
    std::string_view itemId,
    std::string_view newName) {
    const bool renamed = RenameEditorGameObject(itemId, newName);
    RefreshScene();
    return renamed;
}

bool EditorSceneRuntime::DeleteGameObject(std::string_view itemId) {
    ResetTransformEditHistory();
    const bool deleted = DeleteEditorGameObject(itemId);
    RefreshScene();
    EnsureSceneSelection();
    return deleted;
}

std::string EditorSceneRuntime::DuplicateGameObject(std::string_view itemId) {
    ResetTransformEditHistory();
    const std::string duplicatedItemId = DuplicateEditorGameObject(itemId);
    if (!duplicatedItemId.empty()) {
        SetSelection(duplicatedItemId);
    } else {
        RefreshScene();
    }
    return duplicatedItemId;
}

bool EditorSceneRuntime::ReparentGameObject(
    std::string_view itemId,
    std::string_view parentItemId) {
    ResetTransformEditHistory();
    const bool reparented =
        ReparentEditorGameObject(itemId, parentItemId);
    RefreshScene();
    return reparented;
}

bool EditorSceneRuntime::MoveGameObjectToRoot(std::string_view itemId) {
    ResetTransformEditHistory();
    const bool moved = MoveEditorGameObjectToRoot(itemId);
    RefreshScene();
    return moved;
}

bool EditorSceneRuntime::CanRemoveSelectedComponent(
    std::string_view componentId) const {
    const EditorSceneComponentDescriptor descriptor =
        ResolveSelectedComponentDescriptor(componentId);
    return descriptor.IsValid() && descriptor.removable;
}

bool EditorSceneRuntime::RemoveSelectedComponent(std::string_view componentId) {
    const EditorSceneComponentDescriptor descriptor =
        ResolveSelectedComponentDescriptor(componentId);
    if (!descriptor.IsValid() || !descriptor.removable) {
        return false;
    }

    const std::optional<GameObject::ID> selectedId = GetSelectedGameObjectId();
    Scene* scene = GetActiveScene();
    if (!selectedId.has_value() || scene == nullptr) {
        return false;
    }

    GameObject* gameObject = scene->FindByID(selectedId.value());
    Component* component =
        const_cast<Component*>(descriptor.component);
    if (gameObject == nullptr || component == nullptr) {
        return false;
    }

    ResetTransformEditHistory();
    const bool removed = gameObject->RemoveComponent(component);
    RefreshScene();
    return removed;
}

bool EditorSceneRuntime::SetSelectedTransformLocalPosition(
    std::string_view componentId,
    const Vector3& position) {
    const EditorSceneComponentDescriptor descriptor =
        ResolveSelectedComponentDescriptor(componentId);
    auto* transform =
        const_cast<TransformComponent*>(
            dynamic_cast<const TransformComponent*>(descriptor.component));
    if (transform == nullptr) {
        return false;
    }

    SceneTransformSnapshot beforeSnapshot = {};
    if (!CaptureSelectedTransformSnapshot(beforeSnapshot)) {
        return false;
    }

    transform->SetLocalPosition(position);

    SceneTransformSnapshot afterSnapshot = {};
    CaptureSelectedTransformSnapshot(afterSnapshot);
    RecordTransformEdit(beforeSnapshot, afterSnapshot);
    return true;
}

bool EditorSceneRuntime::SetSelectedTransformLocalEulerAngles(
    std::string_view componentId,
    const Vector3& eulerAngles) {
    const EditorSceneComponentDescriptor descriptor =
        ResolveSelectedComponentDescriptor(componentId);
    auto* transform =
        const_cast<TransformComponent*>(
            dynamic_cast<const TransformComponent*>(descriptor.component));
    if (transform == nullptr) {
        return false;
    }

    SceneTransformSnapshot beforeSnapshot = {};
    if (!CaptureSelectedTransformSnapshot(beforeSnapshot)) {
        return false;
    }

    transform->SetLocalEulerAngles(eulerAngles);

    SceneTransformSnapshot afterSnapshot = {};
    CaptureSelectedTransformSnapshot(afterSnapshot);
    RecordTransformEdit(beforeSnapshot, afterSnapshot);
    return true;
}

bool EditorSceneRuntime::SetSelectedTransformLocalScale(
    std::string_view componentId,
    const Vector3& scale) {
    const EditorSceneComponentDescriptor descriptor =
        ResolveSelectedComponentDescriptor(componentId);
    auto* transform =
        const_cast<TransformComponent*>(
            dynamic_cast<const TransformComponent*>(descriptor.component));
    if (transform == nullptr) {
        return false;
    }

    SceneTransformSnapshot beforeSnapshot = {};
    if (!CaptureSelectedTransformSnapshot(beforeSnapshot)) {
        return false;
    }

    transform->SetLocalScale(scale);

    SceneTransformSnapshot afterSnapshot = {};
    CaptureSelectedTransformSnapshot(afterSnapshot);
    RecordTransformEdit(beforeSnapshot, afterSnapshot);
    return true;
}

bool EditorSceneRuntime::ApplySelectedComponentMutation(
    std::string_view componentId,
    const std::function<bool(Component&)>& mutation) {
    if (!mutation) {
        return false;
    }

    const EditorSceneComponentDescriptor descriptor =
        ResolveSelectedComponentDescriptor(componentId);
    Component* component = const_cast<Component*>(descriptor.component);
    if (!descriptor.IsValid() || component == nullptr) {
        return false;
    }

    return mutation(*component);
}

const SceneToolState& EditorSceneRuntime::GetToolState() const {
    return m_toolState;
}

SceneToolMode EditorSceneRuntime::GetToolMode() const {
    return m_toolState.mode;
}

SceneToolSpaceMode EditorSceneRuntime::GetToolSpaceMode() const {
    return m_toolState.spaceMode;
}

SceneToolPivotMode EditorSceneRuntime::GetToolPivotMode() const {
    return m_toolState.pivotMode;
}

void EditorSceneRuntime::SetToolMode(SceneToolMode mode) {
    if (m_toolState.mode == mode) {
        return;
    }

    ResetToolInteractionState();
    m_toolState.mode = mode;
}

void EditorSceneRuntime::SetToolSpaceMode(SceneToolSpaceMode mode) {
    if (m_toolState.spaceMode == mode) {
        return;
    }

    ResetToolInteractionState();
    m_toolState.spaceMode = mode;
}

void EditorSceneRuntime::SetToolPivotMode(SceneToolPivotMode mode) {
    if (m_toolState.pivotMode == mode) {
        return;
    }

    ResetToolInteractionState();
    m_toolState.pivotMode = mode;
}

void EditorSceneRuntime::SetHoveredToolHandle(SceneToolHandle handle) {
    if (m_toolState.dragState.active) {
        return;
    }

    m_toolState.hoveredHandle = handle;
}

void EditorSceneRuntime::SetToolInteractionLock(SceneToolInteractionLock lock) {
    m_toolState.interactionLock = lock;
}

void EditorSceneRuntime::ClearToolInteractionLock() {
    m_toolState.interactionLock = SceneToolInteractionLock::None;
}

void EditorSceneRuntime::ResetToolInteractionState() {
    CancelTransformToolDrag();
    ResetToolInteractionTransientState();
}

bool EditorSceneRuntime::CaptureSelectedTransformSnapshot(
    SceneTransformSnapshot& outSnapshot) const {
    const GameObject* selectedGameObject = GetSelectedGameObject();
    if (selectedGameObject == nullptr) {
        outSnapshot = {};
        return false;
    }

    const TransformComponent* transform = selectedGameObject->GetTransform();
    if (transform == nullptr) {
        outSnapshot = {};
        return false;
    }

    outSnapshot = {};
    outSnapshot.targetId = selectedGameObject->GetID();
    outSnapshot.position = transform->GetPosition();
    outSnapshot.rotation = transform->GetRotation();
    outSnapshot.scale = transform->GetScale();
    outSnapshot.valid = true;
    return true;
}

bool EditorSceneRuntime::ApplyTransformSnapshot(
    const SceneTransformSnapshot& snapshot) {
    if (!snapshot.IsValid()) {
        return false;
    }

    Scene* scene = GetActiveScene();
    if (scene == nullptr) {
        return false;
    }

    GameObject* gameObject = scene->FindByID(snapshot.targetId);
    if (gameObject == nullptr) {
        return false;
    }

    TransformComponent* transform = gameObject->GetTransform();
    if (transform == nullptr) {
        return false;
    }

    transform->SetPosition(snapshot.position);
    transform->SetRotation(snapshot.rotation);
    transform->SetScale(snapshot.scale);
    return true;
}

bool EditorSceneRuntime::RecordTransformEdit(
    const SceneTransformSnapshot& before,
    const SceneTransformSnapshot& after) {
    if (!before.IsValid() ||
        !after.IsValid() ||
        before.targetId != after.targetId ||
        TransformSnapshotsMatch(before, after)) {
        return false;
    }

    m_transformUndoStack.push_back({ before, after });
    m_transformRedoStack.clear();
    return true;
}

bool EditorSceneRuntime::BeginTransformToolDrag(
    SceneToolHandle handle,
    const ::XCEngine::UI::UIPoint& startPointerPosition) {
    if (handle == SceneToolHandle::None ||
        m_toolState.mode == SceneToolMode::View) {
        return false;
    }

    SceneTransformSnapshot snapshot = {};
    if (!CaptureSelectedTransformSnapshot(snapshot)) {
        return false;
    }

    CancelTransformToolDrag();
    m_toolState.dragState = {};
    m_toolState.dragState.active = true;
    m_toolState.dragState.mode = m_toolState.mode;
    m_toolState.dragState.handle = handle;
    m_toolState.dragState.startPointerPosition = startPointerPosition;
    m_toolState.dragState.initialTransform = snapshot;
    m_toolState.hoveredHandle = handle;
    m_toolState.activeHandle = handle;
    SetToolInteractionLock(SceneToolInteractionLock::TransformDrag);
    return true;
}

bool EditorSceneRuntime::HasActiveTransformToolDrag() const {
    return m_toolState.dragState.active;
}

const SceneToolDragState* EditorSceneRuntime::GetActiveTransformToolDrag() const {
    return m_toolState.dragState.active ? &m_toolState.dragState : nullptr;
}

bool EditorSceneRuntime::ApplyTransformToolPreview(
    const SceneTransformSnapshot& snapshot) {
    if (!m_toolState.dragState.active ||
        !snapshot.IsValid() ||
        snapshot.targetId != m_toolState.dragState.initialTransform.targetId) {
        return false;
    }

    return ApplyTransformSnapshot(snapshot);
}

bool EditorSceneRuntime::CommitTransformToolDrag() {
    if (!m_toolState.dragState.active) {
        return false;
    }

    SceneTransformSnapshot afterSnapshot = {};
    const bool captured = CaptureSelectedTransformSnapshot(afterSnapshot);
    const SceneTransformSnapshot beforeSnapshot =
        m_toolState.dragState.initialTransform;
    ResetToolInteractionTransientState();

    if (!captured || !afterSnapshot.IsValid() || !beforeSnapshot.IsValid()) {
        return false;
    }

    return RecordTransformEdit(beforeSnapshot, afterSnapshot);
}

void EditorSceneRuntime::CancelTransformToolDrag() {
    if (!m_toolState.dragState.active) {
        return;
    }

    const SceneTransformSnapshot snapshot = m_toolState.dragState.initialTransform;
    if (snapshot.IsValid()) {
        ApplyTransformSnapshot(snapshot);
    }

    ResetToolInteractionTransientState();
}

bool EditorSceneRuntime::CanUndoTransformEdit() const {
    return !m_transformUndoStack.empty();
}

bool EditorSceneRuntime::CanRedoTransformEdit() const {
    return !m_transformRedoStack.empty();
}

bool EditorSceneRuntime::UndoTransformEdit() {
    if (m_transformUndoStack.empty()) {
        return false;
    }

    const TransformEditTransaction transaction = m_transformUndoStack.back();
    if (!ApplyTransformSnapshot(transaction.before)) {
        return false;
    }

    m_transformUndoStack.pop_back();
    m_transformRedoStack.push_back(transaction);
    SetSelection(transaction.before.targetId);
    return true;
}

bool EditorSceneRuntime::RedoTransformEdit() {
    if (m_transformRedoStack.empty()) {
        return false;
    }

    const TransformEditTransaction transaction = m_transformRedoStack.back();
    if (!ApplyTransformSnapshot(transaction.after)) {
        return false;
    }

    m_transformRedoStack.pop_back();
    m_transformUndoStack.push_back(transaction);
    SetSelection(transaction.after.targetId);
    return true;
}

bool EditorSceneRuntime::EnsureSceneViewCamera() {
    if (m_sceneViewCamera.gameObject != nullptr &&
        m_sceneViewCamera.camera != nullptr) {
        return true;
    }

    m_sceneViewCamera = {};
    m_sceneViewCamera.gameObject =
        std::make_unique<GameObject>("EditorSceneCamera");
    m_sceneViewCamera.camera =
        m_sceneViewCamera.gameObject->AddComponent<
            ::XCEngine::Components::CameraComponent>();
    if (m_sceneViewCamera.camera == nullptr) {
        m_sceneViewCamera.gameObject.reset();
        return false;
    }

    m_sceneViewCamera.camera->SetPrimary(false);
    m_sceneViewCamera.camera->SetProjectionType(
        ::XCEngine::Components::CameraProjectionType::Perspective);
    m_sceneViewCamera.camera->SetFieldOfView(60.0f);
    m_sceneViewCamera.camera->SetNearClipPlane(0.03f);
    m_sceneViewCamera.camera->SetFarClipPlane(2000.0f);
    m_sceneViewCamera.controller.Reset();
    ApplySceneViewCameraController();
    return true;
}

void EditorSceneRuntime::ApplySceneViewCameraController() {
    if (m_sceneViewCamera.gameObject == nullptr) {
        return;
    }

    if (auto* transform = m_sceneViewCamera.gameObject->GetTransform();
        transform != nullptr) {
        m_sceneViewCamera.controller.ApplyTo(*transform);
    }
}

EditorSelectionService& EditorSceneRuntime::SelectionService() {
    return *m_selectionService;
}

const EditorSelectionService& EditorSceneRuntime::SelectionService() const {
    return *m_selectionService;
}

bool EditorSceneRuntime::HasHierarchySelection() const {
    return SelectionService().HasSelectionKind(EditorSelectionKind::HierarchyNode);
}

void EditorSceneRuntime::RevalidateSelection() {
    const GameObject* gameObject = GetSelectedGameObject();
    if (gameObject == nullptr) {
        return;
    }

    SelectionService().SetHierarchySelection(
        MakeEditorGameObjectItemId(gameObject->GetID()),
        ResolveGameObjectDisplayName(*gameObject));
}

bool EditorSceneRuntime::HasValidSelection() const {
    return GetSelectedGameObject() != nullptr;
}

EditorSceneComponentDescriptor EditorSceneRuntime::ResolveSelectedComponentDescriptor(
    std::string_view componentId) const {
    std::string typeName = {};
    std::size_t ordinal = 0u;
    if (!ParseEditorComponentId(componentId, typeName, ordinal)) {
        return {};
    }

    const GameObject* gameObject = GetSelectedGameObject();
    if (gameObject == nullptr) {
        return {};
    }

    std::size_t currentOrdinal = 0u;
    for (const Component* component : gameObject->GetComponents<Component>()) {
        if (component == nullptr || component->GetName() != typeName) {
            continue;
        }

        if (currentOrdinal == ordinal) {
            return BuildComponentDescriptor(*component, currentOrdinal);
        }

        ++currentOrdinal;
    }

    return {};
}

bool EditorSceneRuntime::SelectFirstAvailableGameObject() {
    Scene* scene = GetActiveScene();
    if (scene == nullptr) {
        if (HasHierarchySelection()) {
            ClearSelection();
        }
        return false;
    }

    for (GameObject* root : scene->GetRootGameObjects()) {
        if (root == nullptr) {
            continue;
        }

        return SetSelection(root->GetID());
    }

    if (HasHierarchySelection()) {
        ClearSelection();
    }
    return false;
}

void EditorSceneRuntime::ResetTransformEditHistory() {
    m_transformUndoStack.clear();
    m_transformRedoStack.clear();
}

void EditorSceneRuntime::ResetToolInteractionTransientState() {
    m_toolState.hoveredHandle = SceneToolHandle::None;
    m_toolState.activeHandle = SceneToolHandle::None;
    ClearToolInteractionLock();
    m_toolState.dragState = {};
}

void EditorSceneRuntime::ClearInvalidToolInteractionState() {
    if (!HasSceneSelection()) {
        ResetToolInteractionTransientState();
        return;
    }

    if (!m_toolState.dragState.active) {
        return;
    }

    const SceneTransformSnapshot snapshot = m_toolState.dragState.initialTransform;
    Scene* scene = GetActiveScene();
    if (scene == nullptr ||
        !snapshot.IsValid() ||
        scene->FindByID(snapshot.targetId) == nullptr) {
        ResetToolInteractionTransientState();
    }
}

} // namespace XCEngine::UI::Editor::App