#include "MetaCoreRender/MetaCoreFilamentSceneBridge.h"
#include "MetaCorePlatform/MetaCoreWindow.h"
#include "MetaCoreScene/MetaCoreScene.h"
#include "MetaCoreScene/MetaCoreComponents.h"
#include "MetaCoreRender/MetaCoreRenderTypes.h"
#include "MetaCoreRender/MetaCoreImGuiHelper.h"
#include <imgui.h>

#include <filament/Engine.h>
#include <filament/Scene.h>
#include <filament/View.h>
#include <filament/Camera.h>
#include <filament/SwapChain.h>
#include <filament/Renderer.h>
#include <filament/Viewport.h>
#include <filament/TransformManager.h>
#include <filament/Texture.h>
#include <filament/RenderTarget.h>
#include <filament/LightManager.h>

#include <gltfio/AssetLoader.h>
#include <gltfio/FilamentAsset.h>
#include <gltfio/ResourceLoader.h>
#include <gltfio/MaterialProvider.h>

#include <utils/Entity.h>
#include <utils/EntityManager.h>

#define GLM_ENABLE_EXPERIMENTAL
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/matrix_transform.hpp>

#include <iostream>
#include <fstream>
#include <unordered_map>
#include <vector>

// 引入 Windows 和 OpenGL 头文件以创建纹理
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <GL/gl.h>

namespace MetaCore {

class MetaCoreFilamentSceneBridge::MetaCoreFilamentSceneBridgeImpl {
public:
    MetaCoreFilamentSceneBridgeImpl() = default;
    
    ~MetaCoreFilamentSceneBridgeImpl() {
        Shutdown();
    }

    bool Initialize(MetaCoreWindow& window) {
        std::cout << "FilamentSceneBridge: Initializing..." << std::endl;
        
        // 创建 Filament Engine (不共享上下文，避免闪退)
        Engine_ = filament::Engine::create();
            
        if (!Engine_) {
            std::cerr << "Failed to create Filament Engine with shared context!" << std::endl;
            return false;
        }

        // 创建绑定真实窗口的交换链
        SwapChain_ = Engine_->createSwapChain((void*)window.GetNativeWindowHandle());
        if (!SwapChain_) {
            std::cerr << "Failed to create Filament SwapChain with window handle!" << std::endl;
            return false;
        }

        // 创建渲染器
        Renderer_ = Engine_->createRenderer();
        
        // 创建场景
        Scene_ = Engine_->createScene();

        // 创建默认灯光
        Light_ = utils::EntityManager::get().create();
        filament::LightManager::Builder(filament::LightManager::Type::DIRECTIONAL)
            .color(filament::Color::toLinear<filament::ACCURATE>({ 1.0f, 1.0f, 1.0f }))
            .intensity(100000.0f)
            .direction({ 0.5f, -1.0f, -0.5f })
            .castShadows(true)
            .build(*Engine_, Light_);
        Scene_->addEntity(Light_);

        // 创建相机
        utils::Entity cameraEntity = utils::EntityManager::get().create();
        Camera_ = Engine_->createCamera(cameraEntity);
        
        // 创建视图
        View_ = Engine_->createView();
        View_->setScene(Scene_);
        View_->setCamera(Camera_);

        // 创建 UI 视图
        UIView_ = Engine_->createView();
        
        // 创建 ImGuiHelper
        ImGuiHelper_ = new MetaCoreImGuiHelper(Engine_, UIView_, "", ImGui::GetCurrentContext());

        // 初始化离屏渲染纹理
        auto [width, height] = window.GetFramebufferSize();
        
        // 1. 创建 Filament 颜色纹理
        FilamentTexture_ = filament::Texture::Builder()
            .width(static_cast<uint32_t>(width))
            .height(static_cast<uint32_t>(height))
            .usage(filament::Texture::Usage::COLOR_ATTACHMENT | filament::Texture::Usage::SAMPLEABLE)
            .format(filament::Texture::InternalFormat::RGBA8)
            .build(*Engine_);
            
        // 2. 创建深度纹理
        DepthTexture_ = filament::Texture::Builder()
            .width(static_cast<uint32_t>(width))
            .height(static_cast<uint32_t>(height))
            .usage(filament::Texture::Usage::DEPTH_ATTACHMENT)
            .format(filament::Texture::InternalFormat::DEPTH24)
            .build(*Engine_);
            
        // 3. 创建 RenderTarget 并绑定
        RenderTarget_ = filament::RenderTarget::Builder()
            .texture(filament::RenderTarget::AttachmentPoint::COLOR, FilamentTexture_)
            .texture(filament::RenderTarget::AttachmentPoint::DEPTH, DepthTexture_)
            .build(*Engine_);
            
        // 4. 设置到 View
        View_->setRenderTarget(RenderTarget_);
        View_->setViewport({0, 0, static_cast<uint32_t>(width), static_cast<uint32_t>(height)});
        
        // 确保开启后处理（为了HDR）
        View_->setPostProcessingEnabled(true);

        // 初始化 gltfio (使用 JIT Shader Provider，需要链接 filamat)
        MaterialProvider_ = filament::gltfio::createJitShaderProvider(Engine_);
        AssetLoader_ = filament::gltfio::AssetLoader::create({ Engine_, MaterialProvider_, nullptr });

        std::cout << "FilamentSceneBridge: Initialized with Offscreen Texture ID: " << GLTextureId_ << std::endl;
        return true;
    }

    void Shutdown() {
        if (Engine_) {
            std::cout << "FilamentSceneBridge: Shutting down..." << std::endl;
            
            // 销毁所有加载的资产
            for (auto& [id, asset] : LoadedAssets_) {
                AssetLoader_->destroyAsset(asset);
            }
            LoadedAssets_.clear();

            // 销毁 gltfio 资源
            if (AssetLoader_) {
                filament::gltfio::AssetLoader::destroy(&AssetLoader_);
                AssetLoader_ = nullptr;
            }
            if (MaterialProvider_) {
                MaterialProvider_->destroyMaterials();
                delete MaterialProvider_;
                MaterialProvider_ = nullptr;
            }

            // 销毁离屏渲染资源
            if (RenderTarget_) {
                Engine_->destroy(RenderTarget_);
                RenderTarget_ = nullptr;
            }
            if (FilamentTexture_) {
                Engine_->destroy(FilamentTexture_);
                FilamentTexture_ = nullptr;
            }
            if (DepthTexture_) {
                Engine_->destroy(DepthTexture_);
                DepthTexture_ = nullptr;
            }
            if (GLTextureId_) {
                glDeleteTextures(1, &GLTextureId_);
                GLTextureId_ = 0;
            }

            // 销毁 View
            Engine_->destroy(View_);
            
            // 销毁相机组件和实体
            if (Camera_) {
                utils::Entity cameraEntity = Camera_->getEntity();
                Engine_->destroyCameraComponent(cameraEntity);
                utils::EntityManager::get().destroy(cameraEntity);
            }
            
            // 销毁其他资源
            Engine_->destroy(Scene_);
            Engine_->destroy(Renderer_);
            Engine_->destroy(SwapChain_);
            
            // 最后销毁 Engine
            filament::Engine::destroy(&Engine_);
            Engine_ = nullptr;
        }
    }

    void SetProjectRootPath(const std::filesystem::path& projectRootPath) {
        ProjectRootPath_ = projectRootPath;
    }

    void SyncScene(const MetaCoreScene& scene, bool compatibilityMeshOnly) {
        if (!AssetLoader_) return;

        for (const auto& gameObject : scene.GetGameObjects()) {
            if (!gameObject.HasComponent<MetaCoreMeshRendererComponent>()) {
                continue;
            }
            
            const auto& meshRenderer = gameObject.GetComponent<MetaCoreMeshRendererComponent>();
            if (meshRenderer.MeshSource != MetaCoreMeshSourceKind::Asset) {
                continue;
            }
            
            std::string modelPath = meshRenderer.SourceModelPath;
            if (modelPath.empty()) {
                continue;
            }
            
            std::filesystem::path absolutePath = ProjectRootPath_ / modelPath;
            
            // 如果已经加载过，更新位置即可
            if (LoadedAssets_.contains(gameObject.GetId())) {
                UpdateTransform(gameObject);
                continue;
            }
            
            // 加载新模型
            std::cout << "FilamentSceneBridge: Loading GLTF: " << absolutePath << std::endl;
            
            std::ifstream file(absolutePath, std::ios::binary);
            if (!file.is_open()) {
                std::cerr << "Failed to open file: " << absolutePath << std::endl;
                continue;
            }
            
            std::vector<char> buffer((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());
            
            filament::gltfio::FilamentAsset* asset = AssetLoader_->createAsset(
                reinterpret_cast<const uint8_t*>(buffer.data()), 
                static_cast<uint32_t>(buffer.size())
            );
            
            if (!asset) {
                std::cerr << "Failed to create asset!" << std::endl;
                continue;
            }
            
            // 加载贴图等资源
            filament::gltfio::ResourceLoader resourceLoader({ Engine_ });
            resourceLoader.loadResources(asset);
            
            // 添加到场景
            Scene_->addEntities(asset->getEntities(), asset->getEntityCount());
            
            LoadedAssets_[gameObject.GetId()] = asset;
            
            // 更新初始位置
            UpdateTransform(gameObject);
        }
    }

    void ApplySceneView(const MetaCoreSceneView& sceneView) {
        if (!Camera_ || !View_) return;

        // 设置相机位置和朝向
        Camera_->lookAt(
            { sceneView.CameraPosition.x, sceneView.CameraPosition.y, sceneView.CameraPosition.z },
            { sceneView.CameraTarget.x, sceneView.CameraTarget.y, sceneView.CameraTarget.z },
            { sceneView.CameraUp.x, sceneView.CameraUp.y, sceneView.CameraUp.z }
        );

        // 获取当前视口大小计算宽高比
        const auto& viewport = View_->getViewport();
        double aspect = 1.0;
        if (viewport.height > 0) {
            aspect = static_cast<double>(viewport.width) / static_cast<double>(viewport.height);
        }

        // 设置透视投影
        double fov = sceneView.VerticalFieldOfViewDegrees;
        double nearClip = 0.1;
        double farClip = 1000.0;
        
        Camera_->setProjection(fov, aspect, nearClip, farClip, filament::Camera::Fov::VERTICAL);
    }

    void RenderAll() {
        if (!Renderer_ || !SwapChain_ || !View_ || !UIView_ || !ImGuiHelper_) {
            return;
        }

        if (Renderer_->beginFrame(SwapChain_)) {
            // 1. 渲染 3D 离屏视口 (输出到 RenderTarget)
            filament::Renderer::ClearOptions options;
            options.clearColor = { 0.11f, 0.12f, 0.14f, 1.0f }; // 深灰色
            options.clear = true;
            Renderer_->setClearOptions(options);
            
            Renderer_->render(View_);

            // 2. 准备并渲染 UI 视口 (输出到 SwapChain)
            ImGuiIO& io = ImGui::GetIO();
            ImGuiHelper_->setDisplaySize(io.DisplaySize.x, io.DisplaySize.y);
            UIView_->setViewport({0, 0, static_cast<uint32_t>(io.DisplaySize.x), static_cast<uint32_t>(io.DisplaySize.y)});
            
            options.clearColor = { 0.11f, 0.12f, 0.14f, 1.0f }; // 灰色
            options.clear = true;
            Renderer_->setClearOptions(options);
            
            ImGuiHelper_->processImGuiCommands(ImGui::GetDrawData(), io);
            
            Renderer_->render(UIView_);

            Renderer_->endFrame();
            
            // 在帧结束、指令提交后，安全地销毁上一帧遗留的旧纹理
            for (auto* tex : OldTextures_) {
                Engine_->destroy(tex);
            }
            OldTextures_.clear();
        }
    }

    uint32_t GetGLTextureId() const {
        return GLTextureId_;
    }

    void Resize(int width, int height) {
        if (width <= 0 || height <= 0) return;
        
        // 【关键修复】：如果大小没有改变，不要重新创建纹理！
        // 否则会导致上一帧传给 ImGui 的纹理指针在这一帧被提前销毁，引发 Use-after-free 崩溃。
        if (FilamentTexture_ && 
            FilamentTexture_->getWidth() == static_cast<uint32_t>(width) && 
            FilamentTexture_->getHeight() == static_cast<uint32_t>(height)) {
            return;
        }
        
        if (RenderTarget_) Engine_->destroy(RenderTarget_);
        if (DepthTexture_) Engine_->destroy(DepthTexture_);
        
        // 【关键修复】：推迟销毁旧纹理，避免当前帧 ImGui 的 DrawList 还在引用它导致崩溃。
        if (FilamentTexture_) {
            OldTextures_.push_back(FilamentTexture_);
        }
        
        FilamentTexture_ = filament::Texture::Builder()
            .width(static_cast<uint32_t>(width))
            .height(static_cast<uint32_t>(height))
            .usage(filament::Texture::Usage::COLOR_ATTACHMENT | filament::Texture::Usage::SAMPLEABLE)
            .format(filament::Texture::InternalFormat::RGBA8)
            .build(*Engine_);
            
        DepthTexture_ = filament::Texture::Builder()
            .width(static_cast<uint32_t>(width))
            .height(static_cast<uint32_t>(height))
            .usage(filament::Texture::Usage::DEPTH_ATTACHMENT)
            .format(filament::Texture::InternalFormat::DEPTH24)
            .build(*Engine_);
            
        RenderTarget_ = filament::RenderTarget::Builder()
            .texture(filament::RenderTarget::AttachmentPoint::COLOR, FilamentTexture_)
            .texture(filament::RenderTarget::AttachmentPoint::DEPTH, DepthTexture_)
            .build(*Engine_);
            
        View_->setRenderTarget(RenderTarget_);
        View_->setViewport({0, 0, static_cast<uint32_t>(width), static_cast<uint32_t>(height)});
    }

    void* GetFilamentTexturePointer() const {
        return FilamentTexture_;
    }

    bool TryGetObjectWorldMatrix(MetaCoreId objectId, glm::mat4& worldMatrix) const {
        return false;
    }

    bool HasRuntimeSyncFailure() const { return false; }
    const std::string& GetLastRuntimeSyncFailure() const { return EmptyString_; }

private:
    void UpdateTransform(const MetaCoreGameObject& gameObject) {
        auto it = LoadedAssets_.find(gameObject.GetId());
        if (it == LoadedAssets_.end()) return;

        filament::gltfio::FilamentAsset* asset = it->second;
        utils::Entity rootEntity = asset->getRoot();
        
        auto& tm = Engine_->getTransformManager();
        auto instance = tm.getInstance(rootEntity);
        if (instance) {
            if (!gameObject.HasComponent<MetaCoreTransformComponent>()) return;
            
            const auto& transform = gameObject.GetComponent<MetaCoreTransformComponent>();
            
            glm::mat4 matrix = glm::mat4(1.0f);
            matrix = glm::translate(matrix, transform.Position);
            matrix = glm::rotate(matrix, glm::radians(transform.RotationEulerDegrees.x), {1, 0, 0});
            matrix = glm::rotate(matrix, glm::radians(transform.RotationEulerDegrees.y), {0, 1, 0});
            matrix = glm::rotate(matrix, glm::radians(transform.RotationEulerDegrees.z), {0, 0, 1});
            matrix = glm::scale(matrix, transform.Scale);
            
            tm.setTransform(instance, *reinterpret_cast<const filament::math::mat4f*>(glm::value_ptr(matrix)));
        }
    }

    filament::Engine* Engine_ = nullptr;
    filament::SwapChain* SwapChain_ = nullptr;
    filament::Renderer* Renderer_ = nullptr;
    filament::Scene* Scene_ = nullptr;
    filament::Camera* Camera_ = nullptr;
    filament::View* View_ = nullptr;

    filament::gltfio::AssetLoader* AssetLoader_ = nullptr;
    filament::gltfio::MaterialProvider* MaterialProvider_ = nullptr;
    
    std::unordered_map<MetaCoreId, filament::gltfio::FilamentAsset*> LoadedAssets_;

    filament::View* UIView_ = nullptr;
    MetaCoreImGuiHelper* ImGuiHelper_ = nullptr;

    GLuint GLTextureId_ = 0;
    filament::Texture* FilamentTexture_ = nullptr;
    filament::Texture* DepthTexture_ = nullptr;
    filament::RenderTarget* RenderTarget_ = nullptr;
    std::vector<filament::Texture*> OldTextures_;
    utils::Entity Light_;

    std::filesystem::path ProjectRootPath_{};
    std::string EmptyString_{};
};

MetaCoreFilamentSceneBridge::MetaCoreFilamentSceneBridge()
    : Impl_(std::make_unique<MetaCoreFilamentSceneBridgeImpl>()) {}

MetaCoreFilamentSceneBridge::~MetaCoreFilamentSceneBridge() = default;

bool MetaCoreFilamentSceneBridge::Initialize(MetaCoreWindow& window) {
    return Impl_->Initialize(window);
}

void MetaCoreFilamentSceneBridge::Shutdown() {
    Impl_->Shutdown();
}

void MetaCoreFilamentSceneBridge::SetProjectRootPath(const std::filesystem::path& projectRootPath) {
    Impl_->SetProjectRootPath(projectRootPath);
}

void MetaCoreFilamentSceneBridge::SyncScene(const MetaCoreScene& scene, bool compatibilityMeshOnly) {
    Impl_->SyncScene(scene, compatibilityMeshOnly);
}

void MetaCoreFilamentSceneBridge::ApplySceneView(const MetaCoreSceneView& sceneView) {
    Impl_->ApplySceneView(sceneView);
}

void MetaCoreFilamentSceneBridge::RenderAll() {
    Impl_->RenderAll();
}

uint32_t MetaCoreFilamentSceneBridge::GetGLTextureId() const {
    return Impl_->GetGLTextureId();
}

void MetaCoreFilamentSceneBridge::Resize(int width, int height) {
    Impl_->Resize(width, height);
}

void* MetaCoreFilamentSceneBridge::GetFilamentTexturePointer() const {
    return Impl_->GetFilamentTexturePointer();
}

bool MetaCoreFilamentSceneBridge::TryGetObjectWorldMatrix(MetaCoreId objectId, glm::mat4& worldMatrix) const {
    return Impl_->TryGetObjectWorldMatrix(objectId, worldMatrix);
}

bool MetaCoreFilamentSceneBridge::HasRuntimeSyncFailure() const {
    return Impl_->HasRuntimeSyncFailure();
}

const std::string& MetaCoreFilamentSceneBridge::GetLastRuntimeSyncFailure() const {
    return Impl_->GetLastRuntimeSyncFailure();
}

}  // namespace MetaCore