#ifndef UNICODE
#define UNICODE
#define UNICODE_WAS_UNDEFINED
#endif

// include the basic windows header file
#include <windows.h>
#include <windowsx.h>

#include <d3d11.h>
#pragma comment (lib, "d3d11.lib")

// global declarations
IDXGISwapChain* swapchain;             // the pointer to the swap chain interface
ID3D11Device* dev;                     // the pointer to our Direct3D device interface
ID3D11DeviceContext* devcon;           // the pointer to our Direct3D device context

// this function initializes and prepares Direct3D for use
void InitD3D(HWND hWnd)
{
    // create a struct to hold information about the swap chain
    DXGI_SWAP_CHAIN_DESC scd;

    // clear out the struct for use
    ZeroMemory(&scd, sizeof(DXGI_SWAP_CHAIN_DESC));

    // fill the swap chain description struct
    scd.BufferCount = 1;                                    // one back buffer
    scd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;     // use 32-bit color
    scd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;      // how swap chain is to be used
    scd.OutputWindow = hWnd;                                // the window to be used
    scd.SampleDesc.Count = 4;                               // how many multisamples
    scd.Windowed = TRUE;                                    // windowed/full-screen mode

    // create a device, device context and swap chain using the information in the scd struct
    D3D11CreateDeviceAndSwapChain(NULL,                         // IDXGIAdapter *pAdapter - Let DXGI take care of what adapter to use (default adapter)
        D3D_DRIVER_TYPE_HARDWARE,     // D3D_DRIVER_TYPE DriverType - hardware or software, or others
        NULL,                         // HMODULE Software
        NULL,                         // UINT Flags
        NULL,                         // D3D_FEATURE_LEVEL *pFeatureLevels
        NULL,                         // UINT FeatureLevels
        D3D11_SDK_VERSION,            // UINT SDKVersion
        &scd,                         // DXGI_SWAP_CHAIN_DESC *pSwapChainDesc
        &swapchain,                   // IDXGISwapChain **ppSwapChain
        &dev,                         // ID3D11Device **ppDevice
        NULL,                         // D3D_FEATURE_LEVEL *FeatureLevel
        &devcon);                     // ID3D11DeviceContext **ppImmediateContext
}

// this is the function that cleans up Direct3D and COM
void CleanD3D()
{
    // close and release all existing COM objects
    swapchain->Release();
    dev->Release();
    devcon->Release();
}

// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd,
    UINT message,
    WPARAM wParam,
    LPARAM lParam);

// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPSTR lpCmdLine,
    int nCmdShow)
{
    // the handle for the window, filled by a function
    HWND hWnd;
    // this struct holds information for the window class
    WNDCLASSEX wc;

    // clear out the window class for use
    ZeroMemory(&wc, sizeof(WNDCLASSEX));

    // fill in the struct with the needed information
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
    wc.lpszClassName = L"WindowClass1";

    // register the window class
    RegisterClassEx(&wc);

    // create rectangle for client area
    RECT wr = { 0, 0, 800, 600 };     // set the size only, but not the position
    AdjustWindowRect(&wr, WS_OVERLAPPEDWINDOW, FALSE);  // adjust the size

    // create the window and use the result as the handle
    hWnd = CreateWindowEx(NULL,
        L"WindowClass1",    // name of the window class
        L"Our First Windowed Program",   // title of the window
        WS_OVERLAPPEDWINDOW,    // window style
        300,    // x-position of the window
        300,    // y-position of the window
        500,    // width of the window
        400,    // height of the window
        NULL,    // we have no parent window, NULL
        NULL,    // we aren't using menus, NULL
        hInstance,    // application handle
        NULL);    // used with multiple windows, NULL

    // display the window on the screen
    ShowWindow(hWnd, nCmdShow);

    // set up and initialize Direct3D
    InitD3D(hWnd);

    // enter the main loop:

    // this struct holds Windows event messages
    MSG msg;

    // wait for the next message in the queue, store the result in 'msg'
    while (true)
    {
        if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            // translate keystroke messages into the right format
            TranslateMessage(&msg);

            // send the message to the WindowProc function
            DispatchMessage(&msg);

            // check if message to quit
            if (msg.message == WM_QUIT)
            {
                break;
            }
        }
        else
        {

        }
    }

    // clean up DirectX and COM
    CleanD3D();

    // return this part of the WM_QUIT message to Windows
    return msg.wParam;
}

// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    // sort through and find what code to run for the message given
    switch (message)
    {
        // this message is read when the window is closed
    case WM_DESTROY:
    {
        // close the application entirely
        PostQuitMessage(0);
        return 0;
    }

    break;
    }

    // Handle any messages the switch statement didn't
    return DefWindowProc(hWnd, message, wParam, lParam);
}