/*
 *  idletrack.c
 *
 *  Authors: mrgentry @ http://www.experts-exchange.com
 *           Herman Bloggs <hermanator12002@yahoo.com>
 *  Date: February, 2003
 *  Description: Track user inactivity.
 *
 *  Andrew Whewell <awhewell@users.sourceforge.net> - 25th June 2004. Added
 *  support for GetLastInputInfo under Windows 2000 and above. This avoids having
 *  IDLETRACK.DLL hook itself into every process on the machine, which makes
 *  upgrades easier. The hook mechanism is also used by key loggers, so not
 *  using hooks doesn't put the willys up programs that keep an eye out for
 *  loggers.
 *
 *  Windows 9x doesn't have GetLastInputInfo - when Gaim runs on these machines
 *  the code silently falls back onto the old hooking scheme.
 */
#define _WIN32_WINNT 0x0500
#include <windows.h>

#define EXPORT __declspec(dllexport)

static HANDLE hMapObject = NULL;
static DWORD *lastTime = NULL;
static HHOOK keyHook = NULL;
static HHOOK mouseHook = NULL;
static HINSTANCE g_hInstance = NULL;
static POINT g_point;

/* GetLastInputInfo address and module - if g_GetLastInputInfo == NULL then
 * we fall back on the old "hook the world" method. GetLastInputInfo was brought
 * in with Windows 2000 so Windows 9x will still hook everything.
 */
typedef BOOL (WINAPI *GETLASTINPUTINFO)(LASTINPUTINFO *);
static HMODULE g_user32 = NULL;
static GETLASTINPUTINFO g_GetLastInputInfo = NULL;

static DWORD* setup_shared_mem() {
	BOOL fInit;

	/* Set up the shared memory. */
	/*hMapObject = CreateFileMapping((HANDLE) 0xFFFFFFFF,  //use paging file
				       NULL,                // no security attributes
				       PAGE_READWRITE,      // read/write access
				       0,                   // size: high 32-bits
				       sizeof(DWORD),       // size: low 32-bits
				       "timermem");         // name of map object
	*/
	hMapObject = CreateFileMapping((HANDLE) 0xFFFFFFFF,
								   NULL,
								   PAGE_READWRITE,
								   0,
								   sizeof(DWORD),
								   "timermem");

	if (hMapObject == NULL)
		return NULL;

	/* The first process to attach initializes memory. */
	fInit = (GetLastError() != ERROR_ALREADY_EXISTS);

	/* Get a pointer to the file-mapped shared memory. */
	/*lastTime = (DWORD*) MapViewOfFile(hMapObject,     // object to map view of
	 *				  FILE_MAP_WRITE, // read/write access
	 *				  0,              // high offset:  map from
	 *				  0,              // low offset:   beginning
	 *				  0);             // default: map entire file
	 */
	lastTime = (DWORD*) MapViewOfFile(hMapObject,
									  FILE_MAP_WRITE,
									  0,
									  0,
									  0);

	if (lastTime == NULL)
		return NULL;

	*lastTime = GetTickCount();

	return lastTime;
}


LRESULT CALLBACK KeyboardProc(int code, WPARAM wParam, LPARAM lParam) {
	if (!(code < 0)) {
                if (lastTime == NULL)
                        lastTime = setup_shared_mem();

                if (lastTime)
                        *lastTime = GetTickCount();
        }
	return CallNextHookEx(keyHook, code, wParam, lParam);
}


LRESULT CALLBACK MouseProc(int code, WPARAM wParam, LPARAM lParam) {
	/* We need to verify that the Mouse pointer has actually moved. */
	if(!(code < 0) && 
           !((g_point.x == ((MOUSEHOOKSTRUCT*)lParam)->pt.x) &&
             (g_point.y == ((MOUSEHOOKSTRUCT*)lParam)->pt.y))) {
                g_point.x = ((MOUSEHOOKSTRUCT*)lParam)->pt.x;
                g_point.y = ((MOUSEHOOKSTRUCT*)lParam)->pt.y;

                if (lastTime == NULL)
                        lastTime = setup_shared_mem();

                if (lastTime)
                        *lastTime = GetTickCount();
	}
	return CallNextHookEx(mouseHook, code, wParam, lParam);
}


EXPORT DWORD wgaim_get_lastactive() {
        DWORD result = 0;

        /* If we have GetLastInputInfo then use it, otherwise use the hooks*/
        if (g_GetLastInputInfo != NULL) {
                LASTINPUTINFO lii;
                memset(&lii, 0, sizeof(lii));
                lii.cbSize = sizeof(lii);
                if (g_GetLastInputInfo(&lii)) {
                        result = lii.dwTime;
                }
        } else {
	        if (lastTime == NULL)
		        lastTime = setup_shared_mem();

	        if (lastTime)
		        result = *lastTime;
        }

	return result;
}


EXPORT BOOL wgaim_set_idlehooks() {
        /* Is GetLastInputInfo available?*/
        g_user32 = LoadLibrary("user32.dll");
        if (g_user32) {
                g_GetLastInputInfo = (GETLASTINPUTINFO)GetProcAddress(g_user32, "GetLastInputInfo");
        }

        /* If we couldn't find GetLastInputInfo then fall back onto the hooking scheme*/
        if (g_GetLastInputInfo == NULL) {
	        /* Set up the shared memory.*/
	        lastTime = setup_shared_mem();
	        if (lastTime == NULL)
		        return FALSE;
	        *lastTime = GetTickCount();

	        /* Set up the keyboard hook.*/
	        keyHook = SetWindowsHookEx(WH_KEYBOARD, KeyboardProc, g_hInstance, 0);
	        if (keyHook == NULL) {
		        UnmapViewOfFile(lastTime);
		        CloseHandle(hMapObject);
		        return FALSE;
	        }

	        /* Set up the mouse hook.*/
	        mouseHook = SetWindowsHookEx(WH_MOUSE, MouseProc, g_hInstance, 0);
	        if (mouseHook == NULL) {
		        UnhookWindowsHookEx(keyHook);
		        UnmapViewOfFile(lastTime);
		        CloseHandle(hMapObject);
		        return FALSE;
	        }
	}

	return TRUE;
}


EXPORT void wgaim_remove_idlehooks() {
        if (g_user32 != NULL)
                FreeLibrary(g_user32);
	if (keyHook)
		UnhookWindowsHookEx(keyHook);
	if (mouseHook)
		UnhookWindowsHookEx(mouseHook);
	if (lastTime)
		UnmapViewOfFile(lastTime);
	if (hMapObject)
		CloseHandle(hMapObject);
}

int WINAPI DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved) {
	switch(dwReason) {
		case DLL_PROCESS_ATTACH:
			g_hInstance = hInstance;
			g_point.x = 0;
			g_point.y = 0;
			break;
		case DLL_PROCESS_DETACH:
			break;
	}
	return TRUE;
}