XCEngine/new_editor/app/Scene/EditorSceneBridge.cpp

#include "Scene/EditorSceneBridge.h"

#include <XCEngine/Components/ComponentFactoryRegistry.h>
#include <XCEngine/Components/GameObject.h>
#include <XCEngine/Components/TransformComponent.h>
#include <XCEngine/Core/Asset/ResourceManager.h>
#include <XCEngine/Scene/Scene.h>
#include <XCEngine/Scene/SceneManager.h>

#include <charconv>
#include <filesystem>
#include <optional>
#include <sstream>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

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

namespace {

using ::XCEngine::Components::Component;
using ::XCEngine::Components::ComponentFactoryRegistry;
using ::XCEngine::Components::GameObject;
using ::XCEngine::Components::Scene;
using ::XCEngine::Components::SceneManager;
using ::XCEngine::Components::TransformComponent;
using ::XCEngine::Resources::ResourceManager;

struct ClipboardNode {
    std::string name = {};
    std::string transformPayload = {};
    std::vector<std::pair<std::string, std::string>> components = {};
    std::vector<ClipboardNode> children = {};
};

Scene* ResolvePrimaryScene() {
    SceneManager& sceneManager = SceneManager::Get();
    if (Scene* activeScene = sceneManager.GetActiveScene();
        activeScene != nullptr) {
        return activeScene;
    }

    const std::vector<Scene*> scenes = sceneManager.GetAllScenes();
    if (!scenes.empty() && scenes.front() != nullptr) {
        sceneManager.SetActiveScene(scenes.front());
        return scenes.front();
    }

    return nullptr;
}

std::pair<std::string, std::string> SerializeComponent(
    const Component* component) {
    std::ostringstream payload = {};
    component->Serialize(payload);
    return { component->GetName(), payload.str() };
}

ClipboardNode CopyGameObjectRecursive(const GameObject& gameObject) {
    ClipboardNode node = {};
    node.name = gameObject.GetName();

    if (const TransformComponent* transform = gameObject.GetTransform();
        transform != nullptr) {
        std::ostringstream payload = {};
        transform->Serialize(payload);
        node.transformPayload = payload.str();
    }

    const auto components = gameObject.GetComponents<Component>();
    for (const Component* component : components) {
        if (component == nullptr || component == gameObject.GetTransform()) {
            continue;
        }

        node.components.push_back(SerializeComponent(component));
    }

    for (GameObject* child : gameObject.GetChildren()) {
        if (child == nullptr) {
            continue;
        }

        node.children.push_back(CopyGameObjectRecursive(*child));
    }

    return node;
}

GameObject* PasteGameObjectRecursive(
    Scene& scene,
    const ClipboardNode& node,
    GameObject* parent) {
    GameObject* gameObject = scene.CreateGameObject(node.name, parent);
    if (gameObject == nullptr) {
        return nullptr;
    }

    if (!node.transformPayload.empty()) {
        if (TransformComponent* transform = gameObject->GetTransform();
            transform != nullptr) {
            std::istringstream transformStream(node.transformPayload);
            transform->Deserialize(transformStream);
        }
    }

    for (const auto& componentData : node.components) {
        Component* component =
            ComponentFactoryRegistry::Get().CreateComponent(
                gameObject,
                componentData.first);
        if (component == nullptr || componentData.second.empty()) {
            continue;
        }

        std::istringstream payloadStream(componentData.second);
        component->Deserialize(payloadStream);
    }

    for (const ClipboardNode& child : node.children) {
        PasteGameObjectRecursive(scene, child, gameObject);
    }

    return gameObject;
}

bool WouldCreateCycle(
    const GameObject& source,
    const GameObject& targetParent) {
    const GameObject* current = &targetParent;
    while (current != nullptr) {
        if (current == &source) {
            return true;
        }
        current = current->GetParent();
    }

    return false;
}

} // namespace

EditorStartupSceneResult EnsureEditorStartupScene(
    const std::filesystem::path& projectRoot) {
    EditorStartupSceneResult result = {};
    if (projectRoot.empty()) {
        return result;
    }

    ResourceManager::Get().SetResourceRoot(projectRoot.string().c_str());

    if (Scene* activeScene = ResolvePrimaryScene();
        activeScene != nullptr) {
        result.ready = true;
        result.sceneName = activeScene->GetName();
        return result;
    }

    const std::filesystem::path startupScenePath =
        (projectRoot / "Assets" / "Scenes" / "Main.xc").lexically_normal();
    SceneManager& sceneManager = SceneManager::Get();

    if (std::filesystem::exists(startupScenePath) &&
        std::filesystem::is_regular_file(startupScenePath)) {
        sceneManager.LoadScene(startupScenePath.string());
        Scene* loadedScene = sceneManager.GetScene(startupScenePath.stem().string());
        if (loadedScene == nullptr) {
            loadedScene = ResolvePrimaryScene();
        } else {
            sceneManager.SetActiveScene(loadedScene);
        }

        if (loadedScene != nullptr) {
            result.ready = true;
            result.loadedFromDisk = true;
            result.scenePath = startupScenePath;
            result.sceneName = loadedScene->GetName();
            return result;
        }
    }

    if (Scene* scene = sceneManager.CreateScene("Main");
        scene != nullptr) {
        sceneManager.SetActiveScene(scene);
        result.ready = true;
        result.sceneName = scene->GetName();
    }

    return result;
}

Scene* GetActiveEditorScene() {
    return ResolvePrimaryScene();
}

bool OpenEditorSceneAsset(const std::filesystem::path& scenePath) {
    if (scenePath.empty()) {
        return false;
    }

    std::error_code errorCode = {};
    if (!std::filesystem::exists(scenePath, errorCode) ||
        errorCode ||
        !std::filesystem::is_regular_file(scenePath, errorCode)) {
        return false;
    }

    SceneManager& sceneManager = SceneManager::Get();
    sceneManager.LoadScene(scenePath.string());
    Scene* loadedScene = sceneManager.GetScene(scenePath.stem().string());
    if (loadedScene == nullptr) {
        loadedScene = ResolvePrimaryScene();
    } else {
        sceneManager.SetActiveScene(loadedScene);
    }

    return loadedScene != nullptr;
}

std::string MakeEditorGameObjectItemId(GameObject::ID id) {
    return id == GameObject::INVALID_ID ? std::string() : std::to_string(id);
}

std::optional<GameObject::ID> ParseEditorGameObjectItemId(
    std::string_view itemId) {
    if (itemId.empty()) {
        return std::nullopt;
    }

    GameObject::ID parsedId = GameObject::INVALID_ID;
    const char* first = itemId.data();
    const char* last = itemId.data() + itemId.size();
    const std::from_chars_result result =
        std::from_chars(first, last, parsedId);
    if (result.ec != std::errc() || result.ptr != last ||
        parsedId == GameObject::INVALID_ID) {
        return std::nullopt;
    }

    return parsedId;
}

GameObject* FindEditorGameObject(std::string_view itemId) {
    Scene* scene = ResolvePrimaryScene();
    const std::optional<GameObject::ID> gameObjectId =
        ParseEditorGameObjectItemId(itemId);
    if (scene == nullptr || !gameObjectId.has_value()) {
        return nullptr;
    }

    return scene->FindByID(gameObjectId.value());
}

bool RenameEditorGameObject(
    std::string_view itemId,
    std::string_view newName) {
    GameObject* gameObject = FindEditorGameObject(itemId);
    if (gameObject == nullptr) {
        return false;
    }

    gameObject->SetName(std::string(newName));
    return true;
}

bool DeleteEditorGameObject(std::string_view itemId) {
    Scene* scene = ResolvePrimaryScene();
    GameObject* gameObject = FindEditorGameObject(itemId);
    if (scene == nullptr || gameObject == nullptr) {
        return false;
    }

    scene->DestroyGameObject(gameObject);
    return true;
}

std::string DuplicateEditorGameObject(std::string_view itemId) {
    Scene* scene = ResolvePrimaryScene();
    GameObject* gameObject = FindEditorGameObject(itemId);
    if (scene == nullptr || gameObject == nullptr) {
        return {};
    }

    const ClipboardNode clipboard = CopyGameObjectRecursive(*gameObject);
    GameObject* duplicate =
        PasteGameObjectRecursive(*scene, clipboard, gameObject->GetParent());
    return duplicate != nullptr
        ? MakeEditorGameObjectItemId(duplicate->GetID())
        : std::string();
}

bool ReparentEditorGameObject(
    std::string_view itemId,
    std::string_view parentItemId) {
    GameObject* gameObject = FindEditorGameObject(itemId);
    GameObject* newParent = FindEditorGameObject(parentItemId);
    if (gameObject == nullptr || newParent == nullptr ||
        gameObject == newParent ||
        gameObject->GetParent() == newParent ||
        WouldCreateCycle(*gameObject, *newParent)) {
        return false;
    }

    gameObject->SetParent(newParent);
    return true;
}

bool MoveEditorGameObjectToRoot(std::string_view itemId) {
    GameObject* gameObject = FindEditorGameObject(itemId);
    if (gameObject == nullptr || gameObject->GetParent() == nullptr) {
        return false;
    }

    gameObject->SetParent(nullptr);
    return true;
}

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