#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <tlhelp32.h>


int flag=0;
FILE *fWrite;
static char LastWindowText[256]= {0};
#define PATH "foo.bar"
int WriteMsg(char msg[]) ;
int CheckWindowChange(void);


int main()
{
	fWrite = fopen(PATH, "a+");
	while(CheckWindowChange()){
	 //alle 100ms prüfen = niedrige cpu last
	 //besser wären events abrufen
	Sleep(100);
	}
	fclose(fWrite);
return 0;
}


int WriteMsg(char msg[]) 
{	
	printf("%s\n", msg);
	int len = strlen(msg), i;
	char c;
	for(i=0; i<len;i++)
	{
		c = msg[i];
		fwrite(&c, 1, 1, fWrite);	
	}
	return(0);
}


int CheckWindowChange(void)
{
	char *buffer = NULL, *date = NULL, *time = NULL, *Title = NULL, *message = NULL;
        DWORD size=50;


	HWND hWnd = GetForegroundWindow();


	Title  = (char *)malloc(256 * sizeof(char));
	ZeroMemory(Title, sizeof(*Title));
	buffer =(char *)malloc(256 * sizeof(char));
	ZeroMemory(buffer, sizeof(*buffer));
        time   = (char *)malloc(256 * sizeof(char));
	ZeroMemory(time, sizeof(*time));
        date   =(char *)malloc(256 * sizeof(char));
	ZeroMemory(date, sizeof(*date));
	message = (char *)malloc(256 * sizeof(char));
	ZeroMemory(message, sizeof(*message));


	// ProzessID holen
	DWORD dwPID;
    GetWindowThreadProcessId( hWnd,&dwPID );
	HANDLE hModuleSnap = INVALID_HANDLE_VALUE;
	MODULEENTRY32 me32;


	  // Abbild der Module dieses Prozesses erstellen(exe,dlls etc...)
	hModuleSnap = CreateToolhelp32Snapshot( TH32CS_SNAPMODULE, dwPID );
	if( hModuleSnap == INVALID_HANDLE_VALUE )
    {
     return( false );
    }


   me32.dwSize = sizeof( MODULEENTRY32 );
 
    // Erstes modul auslesen
   if( !Module32First( hModuleSnap, &me32 ) )
    {
     CloseHandle( hModuleSnap );     
     return( false );
    }

	//Wir benötigen nur den Namen des ersten Modules = exe
	strcpy(Title,me32.szModule);

	GetUserNameA(buffer, &size);
    GetTimeFormat(LOCALE_SYSTEM_DEFAULT, TIME_NOSECONDS, NULL, "HH':'mm tt", time, 50);
    GetDateFormat(LOCALE_SYSTEM_DEFAULT, DATE_LONGDATE, NULL, NULL, date, 50);

	if(strcmp(Title, LastWindowText)) 
	{
		strcpy(LastWindowText,Title); 
		wsprintf(message,"\n%s:%s: %s : '%s'\n", date, time, buffer, Title);
		WriteMsg(message);		
	}
	// Fertig
	CloseHandle( hModuleSnap );
	free(message);
	free(Title);
	free(buffer);
	free(time);
	free(date);
    return(true);
}