#include <SDKDDKVer.h>
#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <tchar.h>

void WatchDirectory(int);

HANDLE *dwChangeHandles = NULL;
HANDLE *dwThreads = NULL;

DWORD WINAPI ThreadProc(LPVOID);

DWORD WINAPI ThreadProc(LPVOID lpParam)
{
	int index = (int)lpParam;

	WatchDirectory(index);

	return 0;
}

void _tmain(int argc, TCHAR *argv[])
{
	int how_many = 50;
	int i;
	DWORD status;
	DWORD dwThreadID;

    if(argc < 2)
    {
        _tprintf(TEXT("Usage: %s <dir> [number]\n"), argv[0]);
		_tprintf(TEXT("  Where number * 64 change notifications will be created and monitored for the same folder <dir>.\n"));
        return;
    }

	if (argc > 2)
		how_many = _tstoi(argv[2]);
	if (how_many <= 0)
		how_many = 100;
	_tprintf(TEXT("Monitoring %s - %d change notifications.\n"), argv[1], how_many * 64);

	dwChangeHandles = (HANDLE *)calloc(how_many * 64, sizeof(HANDLE));
	dwThreads = (HANDLE *)calloc(how_many, sizeof(HANDLE));

	for (i = 0; i < how_many * 64; i++) {
		dwChangeHandles[i] = FindFirstChangeNotification(
			argv[1],                         // directory to watch 
			FALSE,                           // do not watch subtree 
			FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME |
			FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SIZE |
			FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_LAST_ACCESS |
			FILE_NOTIFY_CHANGE_CREATION | FILE_NOTIFY_CHANGE_SECURITY);
		if (dwChangeHandles[i] == INVALID_HANDLE_VALUE || dwChangeHandles[i] == NULL)
		{
			status = GetLastError();
			_tprintf(TEXT("ERROR: FindFirstChangeNotification failed. Error code %lu.\n"), status);
			ExitProcess(status);
		}
	}

	for (i = 0; i < how_many; i++) {
		dwThreads[i] = CreateThread(
			NULL,         // default security attributes
			0,            // default stack size
			(LPTHREAD_START_ROUTINE)ThreadProc,
			(LPVOID)i,    // no thread function arguments
			0,            // default creation flags
			&dwThreadID); // receive thread identifier
	}

	status = WaitForMultipleObjects(how_many, dwThreads,
		TRUE, INFINITE);

	for (i = 0; i < how_many * 64; i++) {
		FindCloseChangeNotification(dwChangeHandles[i]);
	}

	free((void*)dwChangeHandles);
	free((void*)dwThreads);

	ExitProcess(0);
}

void WatchDirectory(int index)
{
   DWORD dwWaitStatus; 
   int idx;
   DWORD status;
   DWORD dwTotal = 0;
   int i;
   BOOL bWaitAll = false;

   while (TRUE) 
   { 
      dwWaitStatus = WaitForMultipleObjects(64, &dwChangeHandles[index * 64], 
		  bWaitAll, INFINITE);
	  if (dwWaitStatus == WAIT_FAILED || (dwWaitStatus >= (WAIT_OBJECT_0 + 64))) {
		  _tprintf(TEXT("ERROR: [%d] WaitForMultipleObjects returned %lu.\n"), index, dwWaitStatus);
		  return;
	  }

	  idx = dwWaitStatus - WAIT_OBJECT_0;
	  dwTotal++;

	  //_tprintf(TEXT("Thread %04d - CNH %d idx %d total %lu\n"), index, index * 64 + idx, idx, dwTotal);

	  if (FindNextChangeNotification(dwChangeHandles[index * 64 + idx]) == FALSE)
	  {
		  status = GetLastError();
		  _tprintf(TEXT("ERROR: [%d] FindNextChangeNotification function failed. Error code %lu\n"), index, status);
		  return;
	  }
   }
}