#include <windows.h>
#include <d3d11.h>

// Variables globales
HINSTANCE hInstance;
HWND hWnd;
D3D_FEATURE_LEVEL featureLevel;
ID3D11Device* pd3dDevice = nullptr;
ID3D11DeviceContext* pImmediateContext = nullptr;
IDXGISwapChain* pSwapChain = nullptr;
ID3D11RenderTargetView* pRenderTargetView = nullptr;

// Prototipos de funciones
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HRESULT InitWindow(HINSTANCE, int);
HRESULT InitDevice();
void CleanupDevice();
void Render();

// Función principal
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nCmdShow) {
    if (FAILED(InitWindow(hInstance, nCmdShow))) {
        return 0;
    }

    if (FAILED(InitDevice())) {
        CleanupDevice();
        return 0;
    }

    // Bucle principal de mensajes
    MSG msg = {0};
    while (WM_QUIT != msg.message) {
        if (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE)) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        } else {
            Render();
        }
    }

    CleanupDevice();
    return (int)msg.wParam;
}

// Implementación de funciones
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
    switch (message) {
        case WM_PAINT:
            ValidateRect(hWnd, nullptr);
            break;
        case WM_DESTROY:
            PostQuitMessage(0);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

HRESULT InitWindow(HINSTANCE hInstance, int nCmdShow) {
    // Registro de la clase de ventana
    WNDCLASSEX wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon(hInstance, (LPCTSTR)IDI_APPLICATION);
    wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wcex.lpszMenuName = nullptr;
    wcex.lpszClassName = L"DirectXExample";
    wcex.hIconSm = LoadIcon(wcex.hInstance, (LPCTSTR)IDI_APPLICATION);
    if (!RegisterClassEx(&wcex)) {
        return E_FAIL;
    }

    // Creación de la ventana
    hWnd = CreateWindow(L"DirectXExample", L"DirectX Example", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, nullptr, nullptr, hInstance, nullptr);
    if (!hWnd) {
        return E_FAIL;
    }

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    return S_OK;
}

HRESULT InitDevice() {
    // Creación del dispositivo y el contexto de dispositivo
    D3D_FEATURE_LEVEL featureLevels[] = {D3D_FEATURE_LEVEL_11_0};
    UINT createDeviceFlags = 0;
    #ifdef _DEBUG
    createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;
    #endif

    HRESULT hr = D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, createDeviceFlags, featureLevels, 1, D3D11_SDK_VERSION, &pd3dDevice, &featureLevel, &pImmediateContext);
    if (FAILED(hr)) {
        return hr;
    }

    // Creación de la cadena de intercambio
    IDXGIFactory* pFactory = nullptr;
    hr = CreateDXGIFactory(__uuidof(IDXGIFactory), (void**)(&pFactory));
    if (FAILED(hr)) {
        return hr;
    }

    DXGI_SWAP_CHAIN_DESC sd;
    ZeroMemory(&sd, sizeof(sd));
    sd.BufferCount = 1;
    sd.BufferDesc.Width = 800;
    sd.BufferDesc.Height = 600;
    sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    sd.BufferDesc.RefreshRate.Numerator = 60;
    sd.BufferDesc.RefreshRate.Denominator = 1;
    sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    sd.OutputWindow = hWnd;
    sd.SampleDesc.Count = 1;
    sd.SampleDesc.Quality = 0;
    sd.Windowed = TRUE;

    hr = pFactory->CreateSwapChain(pd3dDevice, &sd, &pSwapChain);
    pFactory->Release();
    if (FAILED(hr)) {
        return hr;
    }

    // Creación de la vista de destino de renderizado
    ID3D11Texture2D* pBackBuffer = nullptr;
    hr = pSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);
    if (FAILED(hr)) {
        return hr;
    }

    hr = pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &pRenderTargetView);
    pBackBuffer->Release();
    if (FAILED(hr)) {
        return hr;
    }

    pImmediateContext->OMSetRenderTargets(1, &pRenderTargetView, nullptr);

    // Configuración de la vista de la ventana
    D3D11_VIEWPORT vp;
    vp.Width = (FLOAT)800;
    vp.Height = (FLOAT)600;
    vp.MinDepth = 0.0f;
    vp.MaxDepth = 1.0f;
    vp.TopLeftX = 0;
    vp.TopLeftY = 0;
    pImmediateContext->RSSetViewports(1, &vp);

    return S_OK;
}

void CleanupDevice() {
    if (pImmediateContext) pImmediateContext->ClearState();
    if (pRenderTargetView) pRenderTargetView->Release();
    if (pSwapChain) pSwapChain->Release();
    if (pImmediateContext) pImmediateContext->Release();
    if (pd3dDevice) pd3dDevice->Release();
}

void Render() {
    // Limpiar el buffer de color
    float ClearColor[4] = {0.0f, 0.125f, 0.3f, 1.0f};
    pImmediateContext->ClearRenderTargetView(pRenderTargetView, ClearColor);

    // Presentar el buffer
    pSwapChain->Present(0, 0);
}