#include <basalt/export_macro.hpp>
#include <basalt/kernel.hpp>
#include <windows.h>
#include <d3d11.h>
#include <d3dcompiler.h>
#include <wrl/client.h>
#include <vector>
#include <iostream>

using Microsoft::WRL::ComPtr;
#define DXCHK(condition) \
    if (FAILED(condition)) { \
        throw std::runtime_error("bad DirectX calling"); \
    }

#pragma region Win32 Window Creation

// Window procedure for the render window
static LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
        case WM_CLOSE:
            PostQuitMessage(0);
            return 0;
        default:
            break;
    }
    return DefWindowProcW(hwnd, msg, wParam, lParam);
}

// Create a render window for DirectX
static HWND CreateRenderWindow(std::uint32_t width, std::uint32_t height, const std::wstring_view& title) {
    static bool g_CLSREG = false;
    constexpr wchar_t class_name[] = L"DirectXRenderWindowClass";
    std::wstring c_title(title);

    if (!g_CLSREG) {
        WNDCLASSEXW wc = {0};
        wc.cbSize = sizeof(WNDCLASSEXW);
        wc.style = CS_HREDRAW | CS_VREDRAW;
        wc.lpfnWndProc = WndProc;
        wc.hInstance = GetModuleHandleW(nullptr);
        wc.hCursor = LoadCursorW(nullptr, IDC_ARROW);
        wc.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
        wc.lpszClassName = class_name;

        if (!RegisterClassExW(&wc)) {
            throw std::runtime_error("Failed to register window class");
        }
        g_CLSREG = true;
    }

    // Calculate window size including borders
    RECT rect = {0, 0, static_cast<LONG>(width), static_cast<LONG>(height)};
    AdjustWindowRect(&rect, WS_OVERLAPPEDWINDOW, FALSE);

    HWND hwnd = CreateWindowExW(0,
                                class_name,
                                c_title.c_str(),
                                WS_OVERLAPPEDWINDOW ^ WS_THICKFRAME ^ WS_MAXIMIZEBOX,
                                CW_USEDEFAULT,
                                CW_USEDEFAULT,
                                rect.right - rect.left,
                                rect.bottom - rect.top,
                                nullptr,
                                nullptr,
                                GetModuleHandleW(nullptr),
                                nullptr);
    if (!hwnd) {
        throw std::runtime_error("Failed to create render window");
    }

    return hwnd;
}

static void DestroyRenderWindow(HWND hwnd) {
    DestroyWindow(hwnd);
}

/**
 * @brief Non-block event loop.
 * @return True for indicate active exit.
 */
static bool EventLoop() {
    MSG msg;
    if (PeekMessageW(&msg, NULL, 0, 0, PM_REMOVE) == 0) {
        // No msg
        return false;
    } else {
        if (msg.message == WM_QUIT) {
            return true;
        } else {
            TranslateMessage(&msg);
            DispatchMessageW(&msg);
            return false;
        }
    }
}

#pragma endregion

// 立方体顶点（位置）
struct Vertex {
    float x, y, z;
};
// 立方体顶点
Vertex CubeVertices[] = {
    // 前面
    {-1, -1, -1},
    {1, -1, -1},
    {1, 1, -1},
    {-1, -1, -1},
    {1, 1, -1},
    {-1, 1, -1},
    // 后面
    {-1, -1, 1},
    {-1, 1, 1},
    {1, 1, 1},
    {-1, -1, 1},
    {1, 1, 1},
    {1, -1, 1},
    // 左面
    {-1, -1, -1},
    {-1, -1, 1},
    {-1, 1, 1},
    {-1, -1, -1},
    {-1, 1, 1},
    {-1, 1, -1},
    // 右面
    {1, -1, -1},
    {1, 1, -1},
    {1, 1, 1},
    {1, -1, -1},
    {1, 1, 1},
    {1, -1, 1},
    // 顶面
    {-1, 1, -1},
    {1, 1, -1},
    {1, 1, 1},
    {-1, 1, -1},
    {1, 1, 1},
    {-1, 1, 1},
    // 底面
    {-1, -1, -1},
    {-1, -1, 1},
    {1, -1, 1},
    {-1, -1, -1},
    {1, -1, 1},
    {1, -1, -1}};

// 简单顶点着色器（只传位置）
const char* g_VS = R"(
    float4 main(float3 pos : POSITION) : SV_POSITION {
        return float4(pos, 1.0f);
    }
)";

// 简单像素着色器（返回固定颜色）
const char* g_PS = R"(
    float4 main() : SV_TARGET {
        return float4(0.2f, 0.4f, 0.8f, 1.0f);
    }
)";

using ::Basalt::Shared::Kernel::EngineConfig;
using ::Basalt::Shared::Kernel::IEngine;

class DirectX11Engine : public IEngine {
public:
    DirectX11Engine() : IEngine() {}
    virtual ~DirectX11Engine() {}

private:
    HWND window; ///< Win32窗口
    ComPtr<ID3D11Device> device;                    ///< 设备
    ComPtr<ID3D11DeviceContext> context;            ///< 上下文
    ComPtr<IDXGISwapChain> swap_chain;              ///< 交换链
    ComPtr<ID3D11RenderTargetView> rtv;             ///< 渲染目标视图
    ComPtr<ID3D11Texture2D> back_buffer;            ///< 后缓冲
    ComPtr<ID3D11Texture2D> depth_buffer;           ///< 深度缓冲
    ComPtr<ID3D11DepthStencilView> dsv;             ///< 深度模板视图
    ComPtr<ID3D11Texture2D> depth_staging;          ///< 用于CPU读取的深度暂存纹理
    ComPtr<ID3D11VertexShader> vs;                  ///< 顶点着色器
    ComPtr<ID3D11PixelShader> ps;                   ///< 像素着色器
    ComPtr<ID3DBlob> vs_blob;                       ///< 顶点着色器字节码
    ComPtr<ID3DBlob> ps_blob;                       ///< 像素着色器字节码
    ComPtr<ID3D11InputLayout> input_layout;         ///< 输入布局
    ComPtr<ID3D11Buffer> vertex_buffer;             ///< 顶点缓冲
    ComPtr<ID3D11DepthStencilState> depth_state;    ///< 深度状态
    ComPtr<ID3D11RasterizerState> rasterizer_state; ///< 光栅化状态
    std::vector<BYTE> depth_data;                   ///< 深度数据

public:
    virtual void Startup(EngineConfig&& config) override {
        IEngine::Startup(std::move(config));

        // 创建Win32窗口并显示
        if (this->config.headless) {
            window = NULL;
        } else {
            window = CreateRenderWindow(this->config.width, this->config.height, this->config.title);
            ShowWindow(window, SW_SHOW);
            UpdateWindow(window);
        }

        // 初始化 COM
        DXCHK(CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED));

        // 创建设备和上下文
        DXCHK(D3D11CreateDevice(nullptr,
                                D3D_DRIVER_TYPE_HARDWARE,
                                nullptr,
                                D3D11_CREATE_DEVICE_DEBUG,
                                nullptr,
                                0,
                                D3D11_SDK_VERSION,
                                &device,
                                nullptr,
                                &context));

        // 创建交换链（窗口可选，这里仅用于渲染上下文）
        DXGI_SWAP_CHAIN_DESC sd = {};
        sd.BufferDesc.Width = this->config.width;
        sd.BufferDesc.Height = this->config.height;
        sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
        sd.SampleDesc.Count = 1;
        sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
        sd.BufferCount = 1;
        sd.OutputWindow = window;
        sd.Windowed = TRUE;

        ComPtr<IDXGIDevice> dxgi_device;
        DXCHK(device.As(&dxgi_device));
        ComPtr<IDXGIAdapter> adapter;
        DXCHK(dxgi_device->GetAdapter(&adapter));
        ComPtr<IDXGIFactory> factory;
        DXCHK(adapter->GetParent(IID_PPV_ARGS(&factory)));
        DXCHK(factory->CreateSwapChain(device.Get(), &sd, &swap_chain));

        // 创建渲染目标
        DXCHK(swap_chain->GetBuffer(0, IID_PPV_ARGS(&back_buffer)));
        DXCHK(device->CreateRenderTargetView(back_buffer.Get(), nullptr, &rtv));

        // 创建深度缓冲（D32_FLOAT）
        D3D11_TEXTURE2D_DESC depth_desc = {};
        depth_desc.Width = this->config.width;
        depth_desc.Height = this->config.height;
        depth_desc.MipLevels = 1;
        depth_desc.ArraySize = 1;
        depth_desc.Format = DXGI_FORMAT_D32_FLOAT;
        depth_desc.SampleDesc.Count = 1;
        depth_desc.Usage = D3D11_USAGE_DEFAULT;
        depth_desc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
        DXCHK(device->CreateTexture2D(&depth_desc, nullptr, &depth_buffer));

        DXCHK(device->CreateDepthStencilView(depth_buffer.Get(), nullptr, &dsv));

        // 创建 staging texture 用于 CPU 读取深度（R32_FLOAT）
        D3D11_TEXTURE2D_DESC staging_desc = depth_desc;
        staging_desc.Format = DXGI_FORMAT_R32_FLOAT; // 注意：DSV 用 D32_FLOAT，staging 用 R32_FLOAT
        staging_desc.BindFlags = 0;
        staging_desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
        staging_desc.Usage = D3D11_USAGE_STAGING;
        DXCHK(device->CreateTexture2D(&staging_desc, nullptr, &depth_staging));

        // 编译并创建着色器
        DXCHK(D3DCompile(g_VS, static_cast<UINT>(strlen(g_VS)), nullptr, nullptr, nullptr, "main", "vs_4_0", 0, 0, &vs_blob, nullptr));
        DXCHK(D3DCompile(g_PS, static_cast<UINT>(strlen(g_PS)), nullptr, nullptr, nullptr, "main", "ps_4_0", 0, 0, &ps_blob, nullptr));
        DXCHK(device->CreateVertexShader(vs_blob->GetBufferPointer(), vs_blob->GetBufferSize(), nullptr, &vs));
        DXCHK(device->CreatePixelShader(ps_blob->GetBufferPointer(), ps_blob->GetBufferSize(), nullptr, &ps));

        // 输入布局
        D3D11_INPUT_ELEMENT_DESC layout[] = {{"POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0}};
        DXCHK(device->CreateInputLayout(layout, 1, vs_blob->GetBufferPointer(), vs_blob->GetBufferSize(), &input_layout));

        // 顶点缓冲
        D3D11_BUFFER_DESC vb_desc = {};
        vb_desc.ByteWidth = sizeof(CubeVertices);
        vb_desc.Usage = D3D11_USAGE_DEFAULT;
        vb_desc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
        D3D11_SUBRESOURCE_DATA vb_data = {CubeVertices};
        DXCHK(device->CreateBuffer(&vb_desc, &vb_data, &vertex_buffer));

        // 深度测试启用
        D3D11_DEPTH_STENCIL_DESC ds_desc = {};
        ds_desc.DepthEnable = TRUE;
        ds_desc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
        ds_desc.DepthFunc = D3D11_COMPARISON_LESS;
        DXCHK(device->CreateDepthStencilState(&ds_desc, &depth_state));

        // 设置光栅化模式
        D3D11_RASTERIZER_DESC rasterizer_desc;
        ZeroMemory(&rasterizer_desc, sizeof(D3D11_RASTERIZER_DESC));
        rasterizer_desc.FillMode = D3D11_FILL_SOLID;
        rasterizer_desc.CullMode = D3D11_CULL_NONE;
        DXCHK(device->CreateRasterizerState(&rasterizer_desc, &rasterizer_state));

        // 视口
        D3D11_VIEWPORT vp;
        ZeroMemory(&vp, sizeof(D3D11_VIEWPORT));
        vp.TopLeftX = 0;
        vp.TopLeftY = 0;
        vp.Width = (float) this->config.width;
        vp.Height = (float) this->config.height;
        vp.MinDepth = 0.0f;
        vp.MaxDepth = 1.0f;
        context->RSSetViewports(1, &vp); // RSSetViewports doesn't return HRESULT, so no need to wrap

        //// 打开命名管道（需另一进程已创建）
        //constexpr const wchar_t* PipeName = L"\\\\.\\pipe\\54da494c-301a-47a9-9d67-4fbebaeda8cf";
        //hPipe = CreateFileW(PipeName, GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, 0, nullptr);

        //if (hPipe == INVALID_HANDLE_VALUE) {
        //    std::cerr << "Failed to open named pipe. Ensure another process created it.\n";
        //    return;
        //}

        // 缩放深度数据数组到指定大小
        depth_data.resize(this->config.width * this->config.height * sizeof(float));

        //frameCount = 0;
    }

    virtual bool Tick() override {
        if (IEngine::Tick()) return true;

        // Event loop
        if (EventLoop()) return true;

        // 清屏
        float clear_color[] = {0.8f, 0.1f, 0.1f, 1.0f};
        context->ClearRenderTargetView(rtv.Get(), clear_color);
        context->ClearDepthStencilView(dsv.Get(), D3D11_CLEAR_DEPTH, 1.0f, 0);

        // 设置管线
        context->OMSetRenderTargets(1, rtv.GetAddressOf(), dsv.Get());
        context->OMSetDepthStencilState(depth_state.Get(), 1);
        context->RSSetState(rasterizer_state.Get());
        context->VSSetShader(vs.Get(), nullptr, 0);
        context->PSSetShader(ps.Get(), nullptr, 0);
        context->IASetInputLayout(input_layout.Get());
        UINT stride = sizeof(Vertex), offset = 0;
        context->IASetVertexBuffers(0, 1, vertex_buffer.GetAddressOf(), &stride, &offset);
        context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

        // 绘制立方体
        context->Draw(sizeof(CubeVertices) / sizeof(Vertex), 0); // 自动计算顶点数

        //// 复制深度缓冲到 staging texture
        //context->CopyResource(depth_staging.Get(), depth_buffer.Get());

        //// Map 获取数据
        //D3D11_MAPPED_SUBRESOURCE mapped;
        //DXCHK(context->Map(depth_staging.Get(), 0, D3D11_MAP_READ, 0, &mapped));
        //memcpy(depth_data.data(), mapped.pData, this->config.width * this->config.height * sizeof(float));
        //context->Unmap(depth_staging.Get(), 0);

        //// 写入命名管道
        //DWORD written;
        //if (!WriteFile(hPipe, depth_data.data(), static_cast<DWORD>(this->config.width * this->config.height * sizeof(float)), &written, nullptr) || written != this->config.width * this->config.height * sizeof(float)) {
        //    std::cerr << "WriteFile failed or incomplete.\n";
        //}

        // 呈现（可选）
        DXCHK(swap_chain->Present(0, 0));

        //frameCount++;

        return false;
    }

    virtual void Shutdown() override {
        IEngine::Shutdown();

        //if (hPipe != INVALID_HANDLE_VALUE) {
        //    CloseHandle(hPipe);
        //}
        CoUninitialize();
        if (!this->config.headless) {
            CloseWindow(window);
            DestroyRenderWindow(window);
        }
    }
};

BS_EXPORT void* BSCreateInstance() {
    return static_cast<IEngine*>(new DirectX11Engine());
}

BS_EXPORT void BSDestroyInstance(void* instance) {
    delete dynamic_cast<DirectX11Engine*>(static_cast<IEngine*>(instance));
}