StayAwake.c

#include <windows.h>
#include <shellapi.h>
#include <stdlib.h>
#include <time.h>

#define WM_TRAYICON (WM_USER + 1)

NOTIFYICONDATA nid;
HMENU hMenu;
HWND hwnd;
HINSTANCE hInst;

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
  if (msg == WM_TRAYICON)
  {
    if (lParam == WM_RBUTTONUP)
    {
      POINT pt;
      GetCursorPos(&pt);
      SetForegroundWindow(hwnd);
      TrackPopupMenu(hMenu, TPM_BOTTOMALIGN, pt.x, pt.y, 0, hwnd, NULL);
    }
  }
  else if (msg == WM_COMMAND)
  {
    if (LOWORD(wParam) == 1)
    {
      Shell_NotifyIcon(NIM_DELETE, &nid);
      PostQuitMessage(0);
    }
  }
  else if (msg == WM_DESTROY)
  {
    Shell_NotifyIcon(NIM_DELETE, &nid);
    PostQuitMessage(0);
  }
  return DefWindowProc(hwnd, msg, wParam, lParam);
}

void MoveMouseMinimal()
{
  INPUT input = {0};
  input.type = INPUT_MOUSE;
  input.mi.dx = 5;
  input.mi.dwFlags = MOUSEEVENTF_MOVE;
  SendInput(1, &input, sizeof(INPUT));

  Sleep(100);

  input.mi.dx = -5;
  SendInput(1, &input, sizeof(INPUT));
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nCmdShow)
{

  HANDLE hMutex = CreateMutex(NULL, TRUE, "TeamsHelperSingleInstance");
  if (GetLastError() == ERROR_ALREADY_EXISTS)
  {
    return 0;
  }

  hInst = hInstance;
  srand((unsigned)time(NULL));

  WNDCLASS wc = {0};
  wc.lpfnWndProc = WndProc;
  wc.hInstance = hInstance;
  wc.lpszClassName = "TeamsHelperClass";
  RegisterClass(&wc);

  hwnd = CreateWindow("TeamsHelperClass", "Hidden Window",
                      0, 0, 0, 0, 0,
                      HWND_MESSAGE, NULL, hInstance, NULL);

  ZeroMemory(&nid, sizeof(nid));
  nid.cbSize = sizeof(nid);
  nid.hWnd = hwnd;
  nid.uID = 1;
  nid.uFlags = NIF_ICON | NIF_MESSAGE | NIF_TIP;
  nid.uCallbackMessage = WM_TRAYICON;
  nid.hIcon = (HICON)LoadImage(hInst, "logo.ico",
                               IMAGE_ICON, 64, 64, LR_LOADFROMFILE);

  lstrcpy(nid.szTip, "TeamsHelper");
  Shell_NotifyIcon(NIM_ADD, &nid);

  hMenu = CreatePopupMenu();
  AppendMenu(hMenu, MF_STRING, 1, "Exit");

  MoveMouseMinimal();

  int delay = 240 + (rand() % 46);
  SetTimer(hwnd, 1, delay * 1000, NULL);

  MSG msg;
  while (GetMessage(&msg, NULL, 0, 0))
  {
    if (msg.message == WM_TIMER)
    {
      MoveMouseMinimal();
      int next = 240 + (rand() % 46);
      SetTimer(hwnd, 1, next * 1000, NULL);
    }
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }

  ReleaseMutex(hMutex);
  CloseHandle(hMutex);
  return 0;
}