#include <gtest/gtest.h>
#include <XCEngine/Components/AudioListenerComponent.h>
#include <XCEngine/Components/AudioSourceComponent.h>
#include <XCEngine/Scene/Scene.h>
#include <XCEngine/Components/CameraComponent.h>
#include <XCEngine/Components/GameObject.h>
#include <XCEngine/Components/LightComponent.h>
#include <XCEngine/Components/TransformComponent.h>
#include <XCEngine/Core/Math/Vector3.h>
#include <filesystem>
#include <fstream>
#include <sstream>

using namespace XCEngine::Components;
using namespace XCEngine::Math;

namespace {

class TestComponent : public Component {
public:
    TestComponent() = default;
    explicit TestComponent(const std::string& name) : m_customName(name) {}

    std::string GetName() const override {
        return m_customName.empty() ? "TestComponent" : m_customName;
    }

    bool m_awakeCalled = false;
    bool m_updateCalled = false;
    bool m_onDestroyCalled = false;
    int m_startCount = 0;
    int m_updateCount = 0;
    int m_onDestroyCount = 0;
    int* m_externalOnDestroyCount = nullptr;

    void Awake() override { m_awakeCalled = true; }
    void Start() override { ++m_startCount; }
    void Update(float deltaTime) override { m_updateCalled = true; ++m_updateCount; }
    void OnDestroy() override {
        m_onDestroyCalled = true;
        ++m_onDestroyCount;
        if (m_externalOnDestroyCount) {
            ++(*m_externalOnDestroyCount);
        }
    }

private:
    std::string m_customName;
};

class SceneTest : public ::testing::Test {
protected:
    void SetUp() override {
        testScene = std::make_unique<Scene>("TestScene");
    }

    std::filesystem::path GetTempScenePath(const char* fileName) const {
        return std::filesystem::temp_directory_path() / fileName;
    }

    std::unique_ptr<Scene> testScene;
};

TEST(Scene_Test, DefaultConstructor_DefaultName) {
    Scene s;
    
    EXPECT_EQ(s.GetName(), "Untitled");
}

TEST(Scene_Test, NamedConstructor) {
    Scene s("MyScene");
    
    EXPECT_EQ(s.GetName(), "MyScene");
}

TEST_F(SceneTest, CreateGameObject_Simple) {
    GameObject* go = testScene->CreateGameObject("TestObject");
    
    EXPECT_NE(go, nullptr);
    EXPECT_EQ(go->GetName(), "TestObject");
}

TEST_F(SceneTest, CreateGameObject_WithParent) {
    GameObject* parent = testScene->CreateGameObject("Parent");
    GameObject* child = testScene->CreateGameObject("Child", parent);
    
    EXPECT_NE(child, nullptr);
    EXPECT_EQ(child->GetParent(), parent);
}

TEST_F(SceneTest, CreateGameObject_AssignsID) {
    GameObject* go1 = testScene->CreateGameObject("Object1");
    GameObject* go2 = testScene->CreateGameObject("Object2");
    
    EXPECT_NE(go1->GetID(), GameObject::INVALID_ID);
    EXPECT_NE(go2->GetID(), GameObject::INVALID_ID);
    EXPECT_NE(go1->GetID(), go2->GetID());
}

TEST_F(SceneTest, CreateGameObject_AddsToRoot) {
    GameObject* go = testScene->CreateGameObject("RootObject");
    
    auto roots = testScene->GetRootGameObjects();
    
    EXPECT_EQ(roots.size(), 1u);
    EXPECT_EQ(roots[0], go);
}

TEST_F(SceneTest, DestroyGameObject_Simple) {
    GameObject* go = testScene->CreateGameObject("TestObject");
    
    testScene->DestroyGameObject(go);
    
    EXPECT_EQ(testScene->Find("TestObject"), nullptr);
}

TEST_F(SceneTest, DestroyGameObject_WithChildren) {
    GameObject* parent = testScene->CreateGameObject("Parent");
    testScene->CreateGameObject("Child", parent);
    
    testScene->DestroyGameObject(parent);
    
    EXPECT_EQ(testScene->Find("Parent"), nullptr);
    EXPECT_EQ(testScene->Find("Child"), nullptr);
}

TEST_F(SceneTest, DestroyGameObject_CallsOnDestroyOnce) {
    GameObject* go = testScene->CreateGameObject("DestroyMe");
    TestComponent* comp = go->AddComponent<TestComponent>();
    int destroyCount = 0;
    comp->m_externalOnDestroyCount = &destroyCount;

    testScene->DestroyGameObject(go);

    EXPECT_EQ(destroyCount, 1);
}

TEST_F(SceneTest, Find_Exists) {
    testScene->CreateGameObject("FindMe");
    
    GameObject* found = testScene->Find("FindMe");
    
    EXPECT_NE(found, nullptr);
    EXPECT_EQ(found->GetName(), "FindMe");
}

TEST_F(SceneTest, Find_NotExists) {
    GameObject* found = testScene->Find("NonExistent");
    
    EXPECT_EQ(found, nullptr);
}

TEST_F(SceneTest, GetRootGameObjects_ReturnsTopLevel) {
    GameObject* parent = testScene->CreateGameObject("Parent");
    testScene->CreateGameObject("Child", parent);
    
    auto roots = testScene->GetRootGameObjects();
    
    EXPECT_EQ(roots.size(), 1u);
    EXPECT_EQ(roots[0], parent);
}

TEST(Scene_Test, GetRootGameObjects_EmptyScene) {
    Scene emptyScene;
    
    auto roots = emptyScene.GetRootGameObjects();
    
    EXPECT_EQ(roots.size(), 0u);
}

TEST_F(SceneTest, Update_UpdatesActiveObjects) {
    GameObject* go = testScene->CreateGameObject("TestObject");
    TestComponent* comp = go->AddComponent<TestComponent>();
    
    testScene->Update(0.016f);
    
    EXPECT_TRUE(comp->m_updateCalled);
}

TEST_F(SceneTest, Update_SkipsInactiveObjects) {
    GameObject* go = testScene->CreateGameObject("InactiveObject");
    TestComponent* comp = go->AddComponent<TestComponent>();
    go->SetActive(false);
    
    testScene->Update(0.016f);
    
    EXPECT_FALSE(comp->m_updateCalled);
}

TEST_F(SceneTest, Update_RecursivelyUpdatesChildObjects) {
    GameObject* parent = testScene->CreateGameObject("Parent");
    GameObject* child = testScene->CreateGameObject("Child", parent);
    TestComponent* comp = child->AddComponent<TestComponent>();

    testScene->Update(0.016f);

    EXPECT_TRUE(comp->m_updateCalled);
    EXPECT_EQ(comp->m_updateCount, 1);
}

TEST_F(SceneTest, Update_CallsStartOnlyOnceBeforeUpdate) {
    GameObject* go = testScene->CreateGameObject("TestObject");
    TestComponent* comp = go->AddComponent<TestComponent>();

    testScene->Update(0.016f);
    testScene->Update(0.016f);

    EXPECT_EQ(comp->m_startCount, 1);
    EXPECT_EQ(comp->m_updateCount, 2);
}

TEST(Scene_Test, IsActive_DefaultTrue) {
    Scene s;
    
    EXPECT_TRUE(s.IsActive());
}

TEST(Scene_Test, SetActive) {
    Scene s;
    s.SetActive(false);
    
    EXPECT_FALSE(s.IsActive());
}

TEST_F(SceneTest, FindObjectOfType) {
    GameObject* go = testScene->CreateGameObject("TestObject");
    go->AddComponent<TestComponent>();
    
    TestComponent* found = testScene->FindObjectOfType<TestComponent>();
    
    EXPECT_NE(found, nullptr);
}

TEST_F(SceneTest, FindObjectsOfType) {
    GameObject* go1 = testScene->CreateGameObject("Object1");
    GameObject* go2 = testScene->CreateGameObject("Object2");
    go1->AddComponent<TestComponent>();
    go2->AddComponent<TestComponent>();
    
    auto found = testScene->FindObjectsOfType<TestComponent>();
    
    EXPECT_EQ(found.size(), 2u);
}

TEST_F(SceneTest, FindGameObjectWithTag) {
    GameObject* go = testScene->CreateGameObject("MyTag");
    
    GameObject* found = testScene->FindGameObjectWithTag("MyTag");
    
    EXPECT_NE(found, nullptr);
}

TEST_F(SceneTest, OnGameObjectCreated_Event) {
    bool eventFired = false;
    testScene->OnGameObjectCreated().Subscribe([&eventFired](GameObject*) {
        eventFired = true;
    });
    
    testScene->CreateGameObject("TestObject");
    
    EXPECT_TRUE(eventFired);
}

TEST_F(SceneTest, OnGameObjectDestroyed_Event) {
    bool eventFired = false;
    testScene->OnGameObjectDestroyed().Subscribe([&eventFired](GameObject*) {
        eventFired = true;
    });
    
    GameObject* go = testScene->CreateGameObject("TestObject");
    testScene->DestroyGameObject(go);
    
    EXPECT_TRUE(eventFired);
}

TEST_F(SceneTest, Save_And_Load) {
    GameObject* go = testScene->CreateGameObject("SavedObject");
    go->GetTransform()->SetLocalPosition(XCEngine::Math::Vector3(1.0f, 2.0f, 3.0f));
    go->SetActive(true);

    const std::filesystem::path scenePath = GetTempScenePath("test_scene.xc");
    testScene->Save(scenePath.string());

    Scene loadedScene;
    loadedScene.Load(scenePath.string());

    GameObject* loadedGo = loadedScene.Find("SavedObject");
    EXPECT_NE(loadedGo, nullptr);
    EXPECT_EQ(loadedGo->GetTransform()->GetLocalPosition(), XCEngine::Math::Vector3(1.0f, 2.0f, 3.0f));

    std::filesystem::remove(scenePath);
}

TEST_F(SceneTest, Save_ContainsGameObjectData) {
    testScene->CreateGameObject("Player");
    testScene->CreateGameObject("Enemy");

    const std::filesystem::path scenePath = GetTempScenePath("test_scene_multi.xc");
    testScene->Save(scenePath.string());

    std::ifstream file(scenePath);
    std::stringstream buffer;
    buffer << file.rdbuf();
    std::string content = buffer.str();
    file.close();

    EXPECT_TRUE(content.find("Player") != std::string::npos);
    EXPECT_TRUE(content.find("Enemy") != std::string::npos);

    std::filesystem::remove(scenePath);
}

TEST_F(SceneTest, Save_And_Load_PreservesAudioComponents) {
    GameObject* listenerObject = testScene->CreateGameObject("Listener");
    GameObject* sourceObject = testScene->CreateGameObject("Source");

    listenerObject->AddComponent<AudioListenerComponent>();
    sourceObject->AddComponent<AudioSourceComponent>();

    const std::filesystem::path scenePath = GetTempScenePath("test_scene_audio_components.xc");
    testScene->Save(scenePath.string());

    Scene loadedScene;
    loadedScene.Load(scenePath.string());

    GameObject* loadedListenerObject = loadedScene.Find("Listener");
    GameObject* loadedSourceObject = loadedScene.Find("Source");
    ASSERT_NE(loadedListenerObject, nullptr);
    ASSERT_NE(loadedSourceObject, nullptr);

    EXPECT_NE(loadedListenerObject->GetComponent<AudioListenerComponent>(), nullptr);
    EXPECT_NE(loadedSourceObject->GetComponent<AudioSourceComponent>(), nullptr);

    std::filesystem::remove(scenePath);
}

TEST_F(SceneTest, Save_And_Load_PreservesHierarchyAndComponents) {
    testScene->SetName("Serialized Scene");
    testScene->SetActive(false);

    GameObject* parent = testScene->CreateGameObject("Rig Root");
    parent->GetTransform()->SetLocalPosition(Vector3(5.0f, 0.0f, 0.0f));
    parent->SetActive(false);

    auto* light = parent->AddComponent<LightComponent>();
    light->SetLightType(LightType::Spot);
    light->SetIntensity(3.5f);
    light->SetRange(12.0f);
    light->SetSpotAngle(45.0f);
    light->SetCastsShadows(true);

    GameObject* child = testScene->CreateGameObject("Main Camera", parent);
    child->GetTransform()->SetLocalPosition(Vector3(1.0f, 2.0f, 3.0f));
    child->GetTransform()->SetLocalScale(Vector3(2.0f, 2.0f, 2.0f));

    auto* camera = child->AddComponent<CameraComponent>();
    camera->SetProjectionType(CameraProjectionType::Orthographic);
    camera->SetOrthographicSize(7.5f);
    camera->SetNearClipPlane(0.5f);
    camera->SetFarClipPlane(250.0f);
    camera->SetDepth(2.0f);
    camera->SetPrimary(false);

    const std::filesystem::path scenePath = GetTempScenePath("test_scene_hierarchy_components.xc");
    testScene->Save(scenePath.string());

    Scene loadedScene;
    loadedScene.Load(scenePath.string());

    EXPECT_EQ(loadedScene.GetName(), "Serialized Scene");
    EXPECT_FALSE(loadedScene.IsActive());

    GameObject* loadedParent = loadedScene.Find("Rig Root");
    GameObject* loadedChild = loadedScene.Find("Main Camera");
    ASSERT_NE(loadedParent, nullptr);
    ASSERT_NE(loadedChild, nullptr);

    EXPECT_EQ(loadedChild->GetParent(), loadedParent);
    EXPECT_EQ(loadedScene.GetRootGameObjects().size(), 1u);
    EXPECT_FALSE(loadedParent->IsActive());
    EXPECT_EQ(loadedParent->GetTransform()->GetLocalPosition(), Vector3(5.0f, 0.0f, 0.0f));
    EXPECT_EQ(loadedChild->GetTransform()->GetLocalPosition(), Vector3(1.0f, 2.0f, 3.0f));
    EXPECT_EQ(loadedChild->GetTransform()->GetPosition(), Vector3(6.0f, 2.0f, 3.0f));

    auto* loadedLight = loadedParent->GetComponent<LightComponent>();
    ASSERT_NE(loadedLight, nullptr);
    EXPECT_EQ(loadedLight->GetLightType(), LightType::Spot);
    EXPECT_FLOAT_EQ(loadedLight->GetIntensity(), 3.5f);
    EXPECT_FLOAT_EQ(loadedLight->GetRange(), 12.0f);
    EXPECT_FLOAT_EQ(loadedLight->GetSpotAngle(), 45.0f);
    EXPECT_TRUE(loadedLight->GetCastsShadows());

    auto* loadedCamera = loadedChild->GetComponent<CameraComponent>();
    ASSERT_NE(loadedCamera, nullptr);
    EXPECT_EQ(loadedCamera->GetProjectionType(), CameraProjectionType::Orthographic);
    EXPECT_FLOAT_EQ(loadedCamera->GetOrthographicSize(), 7.5f);
    EXPECT_FLOAT_EQ(loadedCamera->GetNearClipPlane(), 0.5f);
    EXPECT_FLOAT_EQ(loadedCamera->GetFarClipPlane(), 250.0f);
    EXPECT_FLOAT_EQ(loadedCamera->GetDepth(), 2.0f);
    EXPECT_FALSE(loadedCamera->IsPrimary());

    std::filesystem::remove(scenePath);
}

TEST_F(SceneTest, SerializeToString_And_DeserializeFromString_PreservesHierarchyAndComponents) {
    testScene->SetName("Round Trip Scene");
    testScene->SetActive(false);

    GameObject* parent = testScene->CreateGameObject("Parent");
    parent->GetTransform()->SetLocalPosition(Vector3(2.0f, 4.0f, 6.0f));
    parent->GetTransform()->SetLocalScale(Vector3(1.5f, 1.5f, 1.5f));

    auto* light = parent->AddComponent<LightComponent>();
    light->SetLightType(LightType::Point);
    light->SetIntensity(4.0f);
    light->SetRange(20.0f);
    light->SetCastsShadows(true);

    GameObject* child = testScene->CreateGameObject("Child Camera", parent);
    child->GetTransform()->SetLocalPosition(Vector3(1.0f, 0.0f, -3.0f));

    auto* camera = child->AddComponent<CameraComponent>();
    camera->SetProjectionType(CameraProjectionType::Perspective);
    camera->SetFieldOfView(72.0f);
    camera->SetNearClipPlane(0.2f);
    camera->SetFarClipPlane(512.0f);
    camera->SetPrimary(true);

    const std::string serialized = testScene->SerializeToString();

    Scene loadedScene;
    loadedScene.DeserializeFromString(serialized);

    EXPECT_EQ(loadedScene.GetName(), "Round Trip Scene");
    EXPECT_FALSE(loadedScene.IsActive());
    EXPECT_EQ(loadedScene.GetRootGameObjects().size(), 1u);

    GameObject* loadedParent = loadedScene.Find("Parent");
    GameObject* loadedChild = loadedScene.Find("Child Camera");
    ASSERT_NE(loadedParent, nullptr);
    ASSERT_NE(loadedChild, nullptr);

    EXPECT_EQ(loadedChild->GetParent(), loadedParent);
    EXPECT_EQ(loadedParent->GetTransform()->GetLocalPosition(), Vector3(2.0f, 4.0f, 6.0f));
    EXPECT_EQ(loadedParent->GetTransform()->GetLocalScale(), Vector3(1.5f, 1.5f, 1.5f));
    EXPECT_EQ(loadedChild->GetTransform()->GetPosition(), Vector3(3.5f, 4.0f, 1.5f));

    auto* loadedLight = loadedParent->GetComponent<LightComponent>();
    ASSERT_NE(loadedLight, nullptr);
    EXPECT_EQ(loadedLight->GetLightType(), LightType::Point);
    EXPECT_FLOAT_EQ(loadedLight->GetIntensity(), 4.0f);
    EXPECT_FLOAT_EQ(loadedLight->GetRange(), 20.0f);
    EXPECT_TRUE(loadedLight->GetCastsShadows());

    auto* loadedCamera = loadedChild->GetComponent<CameraComponent>();
    ASSERT_NE(loadedCamera, nullptr);
    EXPECT_EQ(loadedCamera->GetProjectionType(), CameraProjectionType::Perspective);
    EXPECT_FLOAT_EQ(loadedCamera->GetFieldOfView(), 72.0f);
    EXPECT_FLOAT_EQ(loadedCamera->GetNearClipPlane(), 0.2f);
    EXPECT_FLOAT_EQ(loadedCamera->GetFarClipPlane(), 512.0f);
    EXPECT_TRUE(loadedCamera->IsPrimary());
}

TEST_F(SceneTest, SerializeToString_And_DeserializeFromString_PreservesUUIDs) {
    GameObject* parent = testScene->CreateGameObject("Parent");
    GameObject* child = testScene->CreateGameObject("Child", parent);

    const uint64_t parentUUID = parent->GetUUID();
    const uint64_t childUUID = child->GetUUID();

    const std::string serialized = testScene->SerializeToString();

    Scene loadedScene;
    loadedScene.DeserializeFromString(serialized);

    GameObject* loadedParent = loadedScene.Find("Parent");
    GameObject* loadedChild = loadedScene.Find("Child");
    ASSERT_NE(loadedParent, nullptr);
    ASSERT_NE(loadedChild, nullptr);

    EXPECT_EQ(loadedParent->GetUUID(), parentUUID);
    EXPECT_EQ(loadedChild->GetUUID(), childUUID);
}

TEST_F(SceneTest, Save_ContainsHierarchyAndComponentEntries) {
    GameObject* parent = testScene->CreateGameObject("Parent");
    GameObject* child = testScene->CreateGameObject("Child", parent);
    child->AddComponent<CameraComponent>();
    parent->AddComponent<LightComponent>();

    const std::filesystem::path scenePath = GetTempScenePath("test_scene_format.xc");
    testScene->Save(scenePath.string());

    std::ifstream file(scenePath);
    std::stringstream buffer;
    buffer << file.rdbuf();
    const std::string content = buffer.str();
    file.close();

    EXPECT_TRUE(content.find("gameobject_begin") != std::string::npos);
    EXPECT_TRUE(content.find("parent=" + std::to_string(parent->GetID())) != std::string::npos);
    EXPECT_TRUE(content.find("component=Camera;") != std::string::npos);
    EXPECT_TRUE(content.find("component=Light;") != std::string::npos);

    std::filesystem::remove(scenePath);
}

} // namespace