/*
 *  Copyright 2003 J Brown
 *  Copyright 2006 Eric Kohl
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <windows.h>
#include <tchar.h>

#define APPNAME _T("Scrnsave")


HINSTANCE hInstance;

BOOL fullscreen = FALSE;


LRESULT WINAPI WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	static POINT ptLast;
	static POINT ptCursor;
	static BOOL  fFirstTime = TRUE;

	switch (msg)
	{
		case WM_DESTROY:
			PostQuitMessage(0);
			break;

		// break out of screen-saver if any keyboard activity
		case WM_NOTIFY:
		case WM_SYSKEYDOWN:
			PostMessage(hwnd, WM_CLOSE, 0, 0);
			break;

		// break out of screen-saver if any mouse activity
		case WM_LBUTTONDOWN:
		case WM_LBUTTONUP:
		case WM_RBUTTONDOWN:
		case WM_RBUTTONUP:
		case WM_MBUTTONDOWN:
		case WM_MBUTTONUP:
		case WM_MOUSEMOVE:
			// If we've got a parent then we must be a preview
			if(GetParent(hwnd) != 0)
				return 0;

			if(fFirstTime)
			{
				GetCursorPos(&ptLast);
				fFirstTime = FALSE;
			}

		GetCursorPos(&ptCursor);

		// if the mouse has moved more than 3 pixels then exit
		if(abs(ptCursor.x - ptLast.x) >= 3 || abs(ptCursor.y - ptLast.y) >= 3)
			PostMessage(hwnd, WM_CLOSE, 0, 0);

		ptLast = ptCursor;

		return 0;
	}

	return DefWindowProc(hwnd, msg, wParam, lParam);
}

void InitSaver(HWND hwndParent)
{
	WNDCLASS wc;
	ZeroMemory(&wc, sizeof(wc));
	wc.style            = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc      = WndProc;
	wc.lpszClassName    = APPNAME;
	wc.hbrBackground    = (HBRUSH)GetStockObject(BLACK_BRUSH);
	RegisterClass(&wc);

	if (hwndParent != 0)
	{
		RECT rect;
		GetClientRect(hwndParent, &rect);
		CreateWindow(APPNAME, APPNAME,
		             WS_VISIBLE | WS_CHILD,
		             0, 0,
		             rect.right,
		             rect.bottom,
		             hwndParent, 0,
		             hInstance, NULL);
		fullscreen = FALSE;
	}
	else
	{
		HWND hwnd;
		hwnd = CreateWindow(APPNAME, APPNAME,
		                    WS_VISIBLE | WS_POPUP | WS_EX_TOPMOST,
		                    0, 0,
		                    GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN),
		                    HWND_DESKTOP, 0,
		                    hInstance, NULL);
		ShowWindow(hwnd, SW_SHOWMAXIMIZED);
		ShowCursor(FALSE);
		fullscreen = TRUE;
	}
}

void ParseCommandLine(PSTR szCmdLine, int *chOption, HWND *hwndParent)
{
	int ch = *szCmdLine++;

	if(ch == '-' || ch == '/')
		ch = *szCmdLine++;

	if(ch >= 'A' && ch <= 'Z')
		ch += 'a' - 'A';

	*chOption = ch;
	ch = *szCmdLine++;

	if(ch == ':')
		ch = *szCmdLine++;

	while(ch == ' ' || ch == '\t')
		ch = *szCmdLine++;

	if(isdigit(ch))
	{
		unsigned int i = atoi(szCmdLine - 1);
		*hwndParent = (HWND)i;
	}
	else
		*hwndParent = 0;
}

int WINAPI WinMain (HINSTANCE hInst,
                    HINSTANCE hPrev,
                    LPSTR lpCmdLine,
                    int iCmdShow)
{
	HWND	hwndParent;
	UINT	nPreviousState;
	int	chOption;
	MSG	Message;

	hInstance = hInst;

	ParseCommandLine(lpCmdLine, &chOption, &hwndParent);

	SystemParametersInfo(SPI_SETSCREENSAVERRUNNING, TRUE, &nPreviousState, 0);

	switch (chOption)
	{
		case 's':
			InitSaver(0);
			break;

		case 'p':
			InitSaver(hwndParent);
			break;

		case 'c':
		default:
			MessageBox(0,
			           _T("No options need to be set."),
			           _T("About"),
			           MB_OK | MB_ICONWARNING);
			return 0;
	}

	while (GetMessage(&Message, 0, 0, 0))
		DispatchMessage(&Message);

	SystemParametersInfo(SPI_SETSCREENSAVERRUNNING, FALSE, &nPreviousState, 0);

	return Message.wParam;
}
