#define WIN32_LEAN_AND_MEAN
#define WIN32_EXTRA_LEAN

#include <windows.h>
#include <gl/gl.h>
#include <gl/glu.h>
#include <math.h>

#pragma warning(disable:4305)

bool				done = false;
long				windowWidth = 800;
long				windowHeight = 600;
int					m_windowWidth;
int					m_windowHeight;
long				windowBits = 32;
bool				fullscreen = false;
float				m_angle;

HDC					hDC;

void SetupPixelFormat( HDC hDc )
{
	int pixelFormat;

	PIXELFORMATDESCRIPTOR pfd =
	{   
		sizeof(PIXELFORMATDESCRIPTOR),  // size
			1,                          // version
			PFD_SUPPORT_OPENGL |        // OpenGL window
			PFD_DRAW_TO_WINDOW |        // render to window
			PFD_DOUBLEBUFFER,           // support double-buffering
			PFD_TYPE_RGBA,              // color type
			32,                         // prefered color depth
			0, 0, 0, 0, 0, 0,           // color bits (ignored)
			0,                          // no alpha buffer
			0,                          // alpha bits (ignored)
			0,                          // no accumulation buffer
			0, 0, 0, 0,                 // accum bits (ignored)
			16,                         // depth buffer
			0,                          // no stencil buffer
			0,                          // no auxiliary buffers
			PFD_MAIN_PLANE,             // main layer
			0,                          // reserved
			0, 0, 0,                    // no layer, visible, damage masks
	};

	pixelFormat = ChoosePixelFormat(hDC, &pfd);
	SetPixelFormat(hDC, pixelFormat, &pfd);
}

LRESULT CALLBACK MainWindowProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam )
{
//	fprintf( stderr, "MainWindowProc enter." );
	static HDC hDC;
	static HGLRC hRC;
	int height, width;

	switch( uMsg )
	{
	case WM_CREATE:
		hDC = GetDC( hWnd );
		SetupPixelFormat( hDC );
		hRC = wglCreateContext( hDC );
		wglMakeCurrent( hDC, hRC );
		break;

	case WM_DESTROY:
	case WM_QUIT:
	case WM_CLOSE:

		wglMakeCurrent( hDC, NULL );
		wglDeleteContext( hRC );

		PostQuitMessage(0);
		break;

	case WM_SIZE:

		height = HIWORD( lParam );
		width = LOWORD( lParam );

		if ( height == 0 )
		{
			height = 1;
		}

		glViewport( 0, 0, width, height );
		glMatrixMode( GL_PROJECTION );
		glLoadIdentity();

		gluPerspective( 52.0f, (GLfloat)width/(GLfloat)height, 1.0f, 1000.0f );

		glMatrixMode( GL_MODELVIEW );
		glLoadIdentity();

		m_windowHeight = height;
		m_windowWidth = width;
		
		break;

	case WM_ACTIVATEAPP:
		break;

	case WM_PAINT:
		PAINTSTRUCT ps;
		BeginPaint( hWnd, &ps );
		EndPaint( hWnd, &ps );
		break;

	case WM_LBUTTONDOWN:
		break;

	case WM_RBUTTONDOWN:
		break;

	case WM_MOUSEMOVE:
		break;

	case WM_LBUTTONUP:
		break;

	case WM_RBUTTONUP:
		break;

	case WM_KEYUP:
		break;

	case WM_KEYDOWN:
		int fwKeys;
		LPARAM keyData;

		fwKeys = (int)wParam;
		keyData = lParam;

		switch ( fwKeys )
		{
		case VK_ESCAPE:
			PostQuitMessage(0);
			break;
		default:
			break;
		}

		break;

	default:
		break;
	}	

	return DefWindowProc( hWnd, uMsg, wParam, lParam );
}

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd )
{
//	fprintf( stderr, "WinMain run." );

	WNDCLASSEX			windowClass;
	HWND				hWnd;
	MSG					msg;
	DWORD				dwExStyle;
	DWORD				dwStyle;
	RECT				windowRect;

	windowRect.left = (long)0;
	windowRect.right = (long)windowWidth;
	windowRect.top = (long)0;
	windowRect.bottom = (long)windowHeight;

	windowClass.cbSize = sizeof(WNDCLASSEX);
	windowClass.style = CS_HREDRAW | CS_VREDRAW;
	windowClass.lpfnWndProc = MainWindowProc;
	windowClass.cbClsExtra = 0;
	windowClass.cbWndExtra = 0;
	windowClass.hInstance = hInstance;
	windowClass.hIcon = LoadIcon( NULL, IDI_APPLICATION );
	windowClass.hCursor = LoadCursor( NULL, IDC_ARROW );
	windowClass.hbrBackground = NULL;
	windowClass.lpszMenuName = NULL;
	windowClass.lpszClassName = "GLClass";
	windowClass.hIconSm = LoadIcon( NULL, IDI_WINLOGO );

	if ( !RegisterClassEx( &windowClass ))
		return 0;

	if ( fullscreen )
	{
		DEVMODE dmScreenSettings;
		memset( &dmScreenSettings, 0, sizeof( dmScreenSettings ));
		dmScreenSettings.dmSize = sizeof( dmScreenSettings );
		dmScreenSettings.dmPelsWidth = windowWidth;
		dmScreenSettings.dmPelsHeight = windowHeight;
		dmScreenSettings.dmBitsPerPel = windowBits;
		dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;

		if ( ChangeDisplaySettings( &dmScreenSettings, CDS_FULLSCREEN ) != DISP_CHANGE_SUCCESSFUL )
		{
			MessageBox( NULL, "Display mode failed.", NULL, MB_OK );
			fullscreen = FALSE;
		}
	}

	if ( fullscreen )
	{
		dwExStyle = WS_EX_APPWINDOW;
		dwStyle = WS_POPUP;
		ShowCursor( FALSE );
	}
	else
	{
		dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
		dwStyle = WS_OVERLAPPEDWINDOW;
	}

	AdjustWindowRectEx( &windowRect, dwStyle, FALSE, dwExStyle );

	hWnd = CreateWindowEx(NULL,                                 // extended style
		"GLClass",                          // class name
		"BOGLGP - Chapter 2 - OpenGL Application",      // app name
		dwStyle | WS_CLIPCHILDREN |
		WS_CLIPSIBLINGS,
		0, 0,                               // x,y coordinate
		windowRect.right - windowRect.left,
		windowRect.bottom - windowRect.top, // width, height
		NULL,                               // handle to parent
		NULL,                               // handle to menu
		hInstance,                          // application instance
		NULL); 
	hDC = GetDC( hWnd );

	if ( !hWnd )
		return 0;

	ShowWindow( hWnd, SW_SHOW );
	UpdateWindow( hWnd );

	glClearColor( 0.0, 0.0, 0.0, 0.0 );
	m_angle = 0.0f;

	while( !done )
	{
		m_angle += 0.1f;

		glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
		glLoadIdentity();
		
		glTranslatef( 0.0, 0.0, -5.0f );
		glRotatef( m_angle, 1.0f, 0.0f, 0.0f );
		glRotatef( m_angle, 0.0f, 1.0f, 0.0f );
		glRotatef( m_angle, 0.0f, 0.0f, 1.0f );

		glColor3f( 0.7f, 1.0f, 0.3f );

		glBegin( GL_TRIANGLES );
			glVertex3f( 1.0f, -1.0f, 0.0f );
			glVertex3f( -1.0f, -1.0f, 0.0f );
			glVertex3f( 0.0f, 1.0f, 0.0f );
		glEnd();

		SwapBuffers( hDC );

		while ( PeekMessage( &msg, NULL, 0, 0, PM_NOREMOVE ) )
		{
			if ( !GetMessage( &msg, NULL, 0, 0 ) )
			{
				done = true;
				break;
			}

			TranslateMessage( &msg );
			DispatchMessage( &msg );
		}

	}

	if ( fullscreen )
	{
		ChangeDisplaySettings( NULL, 0 );
		ShowCursor( TRUE );
	}

	return (int)msg.wParam;

}