function IsUserActive(MS: dword): boolean;
var
  liInfo: TLastInputInfo;
begin;
  liInfo.cbSize:=SizeOf(TLastInputInfo);
  GetLastInputInfo(liInfo);
  Result:=(GetTickCount-liInfo.dwTime<MS);
  end;

unit LastAppInputHook;

interface

uses
  Windows;

function GetLastAppInputTick: dword;
function IsAppIdle(ms: dword): boolean;

implementation

var
  MouseHook: HHook= 0;
  KeyboardHook: HHook= 0;
  LastHookTick: dword= 0;

function GetLastAppInputTick: dword;
begin;
  Result:=LastHookTick;
  end;

function IsAppIdle(ms: dword): boolean;
begin;
  Result:=(GetTickCount-LastHookTick>=ms);
  end;

function MouseProc(Code, wParam, lParam: integer): integer; stdcall;
begin;
  Result:=CallNextHookEx(MouseHook, Code, WParam, LParam);
  LastHookTick:=GetTickCount;
  end;

function KeyboardProc(Code, wParam, lParam: integer): integer; stdcall;
begin;
  Result:=CallNextHookEx(KeyboardHook, Code, WParam, LParam);
  LastHookTick:=GetTickCount;
  end;

procedure Hook;
begin;
  MouseHook   :=SetWindowsHookEx(WH_MOUSE,    MouseProc,    0, GetCurrentThreadID);
  KeyboardHook:=SetWindowsHookEx(WH_KEYBOARD, KeyboardProc, 0, GetCurrentThreadID);
  LastHookTick:=GetTickCount;
  end;

procedure Unhook;
begin;
  if MouseHook<>0 then UnhookWindowsHookEx(MouseHook);
  if KeyboardHook<>0 then UnhookWindowsHookEx(KeyboardHook);
  end;

initialization
  Hook;

finalization
  Unhook;

end.