#define WIN32_LEAN_AND_MEAN
#include <windows.h>

#include <mmsystem.h>
#include <d3d8.h>
#include <d3dx8.h>


struct SGlobal
{
	HWND				m_hMainWindow;

	LPDIRECT3D8			m_pD3D;
	LPDIRECT3DDEVICE8	m_pDevice;

	int					m_wide;
	int					m_tall;

	D3DPRESENT_PARAMETERS	m_SavedPresentationParameters;

} G;

int ShowError( const char* zStr, int retcode = E_FAIL)
{
	OutputDebugString( zStr);
	OutputDebugString( "\n");

	return retcode;
}

long DoPaint( HWND hWnd, UINT uMessage, WPARAM wParam, LPARAM lParam)
{
	PAINTSTRUCT PaintStruct;
	HDC hDC;
	hDC = BeginPaint( hWnd, &PaintStruct);
	// Do Paint stuff vvvvvvv



	// Done with Paint stuff ^^^^^^^
	EndPaint( hWnd, &PaintStruct);
	return 0;
}

long CALLBACK WindowProc( HWND hWnd, UINT uMessage, WPARAM wParam, LPARAM lParam)
{
	switch( uMessage) {

		case WM_CREATE:
			return 0;

		case WM_PAINT:
			ValidateRect( hWnd, NULL); // may windows think I did the update;
			return 0;

		case WM_DESTROY:
			PostQuitMessage(0);
			return 0;

		default:
			return DefWindowProc( hWnd, uMessage, wParam, lParam);
	}
}

int InitDirect3DDevice( HWND hWndTarget,
					    int wide,
						int tall,
						BOOL fWindowed,
						D3DFORMAT FullScreenFormat,
						LPDIRECT3D8 pD3D,
						LPDIRECT3DDEVICE8 *ppDevice)
{
	HRESULT					hr;
	D3DDISPLAYMODE			d3ddm;
	D3DPRESENT_PARAMETERS	d3dpp;

	if ( *ppDevice)
		(*ppDevice)->Release();

	ZeroMemory( &d3dpp, sizeof( D3DPRESENT_PARAMETERS));
	
	hr = G.m_pD3D->GetAdapterDisplayMode( D3DADAPTER_DEFAULT, &d3ddm);
	if (FAILED(hr))
		return ShowError( "Could not get display adapter information");

	d3dpp.BackBufferWidth = wide;
	d3dpp.BackBufferHeight = tall;
	d3dpp.BackBufferFormat = fWindowed ? d3ddm.Format : FullScreenFormat;

	d3dpp.BackBufferCount = 1;
	d3dpp.MultiSampleType = D3DMULTISAMPLE_NONE;
	d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;

	d3dpp.hDeviceWindow = hWndTarget;
	d3dpp.Windowed = fWindowed;

	d3dpp.EnableAutoDepthStencil = TRUE;
	d3dpp.AutoDepthStencilFormat = D3DFMT_D16;

	d3dpp.FullScreen_RefreshRateInHz = 0; // use default

	d3dpp.FullScreen_PresentationInterval = fWindowed ? 0 : D3DPRESENT_INTERVAL_IMMEDIATE;

	d3dpp.Flags = D3DPRESENTFLAG_LOCKABLE_BACKBUFFER;

	hr = G.m_pD3D->CreateDevice(
		D3DADAPTER_DEFAULT,
		D3DDEVTYPE_HAL,
		hWndTarget,
		D3DCREATE_SOFTWARE_VERTEXPROCESSING,
		&d3dpp,
		ppDevice
	);
	if (FAILED(hr))
		return ShowError( "Could not create render device");

	G.m_wide = wide;
	G.m_tall = tall;
	G.m_SavedPresentationParameters = d3dpp;

	return S_OK;
}
	

int D3DInit()
{
	HRESULT					hr;

	G.m_pD3D	= Direct3DCreate8( D3D_SDK_VERSION );
	if ( !G.m_pD3D) {
		return E_FAIL;
	}

	hr = InitDirect3DDevice(
		G.m_hMainWindow,
		640,
		480,
		TRUE,
		D3DFMT_X8R8G8B8,
		G.m_pD3D,
		&G.m_pDevice
	);
	if (FAILED(hr))
		return ShowError( "Initialization of the device failed");

	return S_OK;
}

void SetPixel32( int x, int y, DWORD color, int pitch, DWORD* pData)
{
	if ( (x >= G.m_wide) || (x < 0) )
		return;
	if ( (y >= G.m_tall) || (y < 0) )
		return;
	pData[ (((pitch/4) * y) + x) ] = color;
}

int Render()
{
	HRESULT hr;
	D3DLOCKED_RECT lockedRect;
	LPDIRECT3DSURFACE8 pBackSurf;

	if ( !G.m_pDevice)
		return ShowError( "Cannot render, there is no device");

#if 1
	G.m_pDevice->Clear(
		0,
		0,
		D3DCLEAR_TARGET,
		D3DCOLOR_XRGB( 0, 0, 0),
		1.0f,
		0
	);
#endif

	hr = G.m_pDevice->GetBackBuffer(
		0,
		D3DBACKBUFFER_TYPE_MONO,
		&pBackSurf
	);
	if (FAILED(hr))
		return ShowError( "Could NOT get back buffer");

	hr = pBackSurf->LockRect( &lockedRect, NULL, 0);
	if (FAILED(hr))
		return ShowError( "Could NOT lock the back buffer");

	DWORD *pData = (DWORD*)(lockedRect.pBits);
	// Draw into pData buffer Starts vvvvv

	for ( int i = 0; i < 50000; i++) {
		SetPixel32(
			rand()%(G.m_wide-1),
			rand()%(G.m_tall),
			D3DCOLOR_XRGB( 255, 0, 0),
			lockedRect.Pitch,
			pData
		);
	}

	// Draw into pData buffer Ends   ^^^^^
	pBackSurf->UnlockRect();
	pBackSurf->Release();

	G.m_pDevice->Present( NULL, NULL, NULL, NULL);

	return S_OK;
}

void D3DIdleProc()
{
	Render();
}

void D3DShutdown()
{
}

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
	MSG			msg;
	WNDCLASSEX	wc;

	static char strAppName[] = "DirectDrawSimple";

	wc.cbSize			= sizeof( WNDCLASSEX);
	wc.style			= CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
	wc.cbClsExtra		= 0;
	wc.cbWndExtra		= 0;
	wc.lpfnWndProc		= WindowProc;
	wc.hInstance		= hInstance;
	wc.hbrBackground	= (HBRUSH) GetStockObject( DKGRAY_BRUSH);
	wc.hIcon			= LoadIcon( NULL, IDI_APPLICATION);
	wc.hIconSm			= LoadIcon( NULL, IDI_HAND);
	wc.hCursor			= LoadCursor( NULL, IDC_CROSS);
	wc.lpszMenuName		= NULL;
	wc.lpszClassName	= strAppName;

	RegisterClassEx( &wc);

	G.m_hMainWindow = CreateWindowEx(
		NULL,
		strAppName,
		strAppName,
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT,			// x pos
		CW_USEDEFAULT,			// y pos
		512,					// wide
		512,					// tall
		NULL,
		NULL,					// Handle to Menu
		hInstance,
		NULL );

	ShowWindow( G.m_hMainWindow, nCmdShow);
	UpdateWindow( G.m_hMainWindow);

	if ( FAILED(D3DInit()) ) {
		return E_FAIL;
	}

	for(;;) {
		if ( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE) ) {

			if ( msg.message == WM_QUIT ) {
				break;
			}

			TranslateMessage( &msg);
			DispatchMessage( &msg);
		} else {
			D3DIdleProc();
		}
	}

	D3DShutdown();

	return msg.wParam;
}