#include <windows.h>
#include <d3d9.h>
#include <d3dx9tex.h>
#include <string>

HINSTANCE hInst;
HWND wndHandle;

bool initWindow(HINSTANCE hInstance);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

// DirectX functions and global variables
HRESULT                 lastResult;
LPDIRECT3D9             pD3D;
LPDIRECT3DDEVICE9       pd3dDevice;
IDirect3DSurface9*		bkgrd;

bool initDirect3D(HWND hwnd);
IDirect3DSurface9* getSurfaceFromBitmap(std::string filename);
void Render(void);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
	if (!initWindow(hInstance))
		return false;
	
	if (!initDirect3D(wndHandle))
		return false;

	bkgrd = getSurfaceFromBitmap("./background.bmp");
	if (bkgrd == NULL)
	{
		MessageBox(NULL, "Make sure the file background.bmp is in the current directory", "ERROR", MB_OK);
		return 0;
	}

	// Main message loop:
	// Enter the message loop
    MSG msg; 
    ZeroMemory( &msg, sizeof(msg) );
    while( msg.message!=WM_QUIT )
    {
		if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
        {
			TranslateMessage( &msg );
            DispatchMessage( &msg );
        }
		else
		{
			// call our render function
			Render();
		}
    }

	if( pd3dDevice != NULL) 
	{
        pd3dDevice->Release();
		pd3dDevice = NULL;
	}
    if( pD3D != NULL)
	{
        pD3D->Release();
		pD3D = NULL;
	}

	return (int) msg.wParam;
}

bool initWindow(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX);
	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= (WNDPROC)WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= 0;
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= NULL;
	wcex.lpszClassName	= "DirectXExample";
	wcex.hIconSm		= 0;
	RegisterClassEx(&wcex);

	wndHandle = CreateWindow("DirectXExample", 
							 "DirectXExample", 
							 WS_OVERLAPPEDWINDOW,
							 CW_USEDEFAULT, 
							 CW_USEDEFAULT, 
							 640, 
							 480, 
							 NULL, 
							 NULL, 
							 hInstance, 
							 NULL);
   if (!wndHandle)
      return false;
   
   ShowWindow(wndHandle, SW_SHOW);
   UpdateWindow(wndHandle);

   return true;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message) 
	{
		case WM_DESTROY:
			PostQuitMessage(0);
			break;
	}
	return DefWindowProc(hWnd, message, wParam, lParam);
}

bool initDirect3D(HWND hwnd)
{
	if( NULL == ( pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
	{
		lastResult = E_FAIL;
		return false;
	}

	D3DPRESENT_PARAMETERS d3dpp; 
    ZeroMemory( &d3dpp, sizeof(d3dpp) );
    d3dpp.Windowed = TRUE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;
	d3dpp.BackBufferCount  = 1;
	d3dpp.BackBufferHeight = 480;
	d3dpp.BackBufferWidth  = 640;
	d3dpp.hDeviceWindow    = hwnd;

    if( FAILED( pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hwnd,
                                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                                      &d3dpp, &pd3dDevice ) ) )
    {
		lastResult = E_FAIL;
        return false;
    }

	return true;
}

IDirect3DSurface9* getSurfaceFromBitmap(std::string filename)
{
	HRESULT hResult;
	IDirect3DSurface9* surface = NULL;
	D3DXIMAGE_INFO imageInfo;

	// Get the width and height info from this bitmap
	hResult = D3DXGetImageInfoFromFile(filename.c_str(), &imageInfo);
	if FAILED (hResult)
		return NULL;

	hResult = pd3dDevice->CreateOffscreenPlainSurface(imageInfo.Width, imageInfo.Height, D3DFMT_X8R8G8B8, D3DPOOL_DEFAULT, &surface, NULL);
	if (FAILED(hResult))
		return NULL;

	hResult = D3DXLoadSurfaceFromFile(surface, NULL, NULL, filename.c_str(), NULL, D3DX_DEFAULT, 0, NULL);
	if (FAILED(hResult))
		return NULL;

	return surface;
}

void Render(void)
{
	if( NULL == pd3dDevice )
        return;

    // Clear the backbuffer to a blue color
    pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );
	
	IDirect3DSurface9* backbuffer;
	pd3dDevice->GetBackBuffer(0,0,D3DBACKBUFFER_TYPE_MONO, &backbuffer);

	HRESULT hResult = pd3dDevice->StretchRect(bkgrd, NULL, backbuffer, NULL, D3DTEXF_NONE);
	if (hResult != D3D_OK)
		MessageBox(NULL,"failed", "error", MB_OK);

	// Present the backbuffer contents to the display
    pd3dDevice->Present( NULL, NULL, NULL, NULL );
}