library Project1;

uses
  Windows,
  Messages,
  SysUtils,
  Registry;

var
  g_hHookKbdLL: HHOOK = 0;
  g_hHookKbd: HHOOK = 0;
  HookHandle: Cardinal = 0;
  WindowHandle: Cardinal = 0;

const
  WH_KEYBOARD_LL = 13;
  LLKHF_ALTDOWN = 32;
  WM_HOOKMESSAGEID = WM_USER + 7328;
type
  KBDLLHOOKSTRUCT = record
                      vkCode: DWORD;
                      scanCode: DWORD;
                      flags: DWORD;
                      time: DWORD;
                      dwExtraInfo: DWORD;
                    end;
  PKBDLLHOOKSTRUCT = ^KBDLLHOOKSTRUCT;

function MyTaskKeyHookLL(nCode: Integer; wp: WPARAM; lp: LPARAM): LRESULT; stdcall;
var
  pkh: PKBDLLHOOKSTRUCT;
  bCtrlKeyDown: BOOL;
begin
  pkh:=PKBDLLHOOKSTRUCT(lp);

  if nCode=HC_ACTION then
  begin
    bCtrlKeyDown := GetAsyncKeyState(VK_CONTROL) shr ((sizeof(SHORT) * 8) - 1)<>0;
       // Ctrl+Esc
    if ((pkh^.vkCode=VK_ESCAPE) and bCtrlKeyDown) or
       // Alt+F4
       ((pkh^.vkCode=VK_F4) and (pkh^.flags and LLKHF_ALTDOWN=LLKHF_ALTDOWN)) or
       // Alt+TAB
       ((pkh^.vkCode=VK_TAB) and (pkh^.flags and LLKHF_ALTDOWN=LLKHF_ALTDOWN)) or
       // Alt+Esc
       ((pkh^.vkCode=VK_ESCAPE) and (pkh^.flags and LLKHF_ALTDOWN=LLKHF_ALTDOWN)) or
       // Start Menu
       ((pkh^.vkCode=VK_LWIN) or (pkh^.vkCode=VK_RWIN)) then
    begin
      result:=1;
      exit;
    end;
  end;
  result:=CallNextHookEx(g_hHookKbdLL, nCode, wp, lp);
end;

function KeyboardHookProc(nCode: Integer; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
begin
  Result := CallNextHookEx(HookHandle, nCode, wParam, lParam);
  case nCode < 0 of
    TRUE: exit;
    FALSE: Postmessage(WindowHandle,WM_HOOKMESSAGEID,0,0);
  end;
end;

function DisableTaskKeys(bDisable: bool): bool; stdcall;
begin
  if bDisable then
  begin
    if g_hHookKbdLL=0 then
     g_hHookKbdLL := SetWindowsHookEx(WH_KEYBOARD_LL, MyTaskKeyHookLL, HInstance, 0);
  end
  else
  if g_hHookKbdLL<>0 then
  begin
    UnhookWindowsHookEx(g_hHookKbdLL);
    g_hHookKbdLL := 0;
  end;
  result:=g_hHookKbdLL<>0;
end;

function EnableKeyboardCheck(HWND: Cardinal; Activate: Boolean): boolean; stdcall;
begin
  if Activate = TRUE then
    begin
      Result := False;
      if HookHandle = 0 then begin
        HookHandle := SetWindowsHookEx(WH_KEYBOARD_LL, @KeyboardHookProc, HInstance, 0);
        WindowHandle := Hwnd;
        Result := TRUE;
      end;
    end
  else
    begin
      Result := UnhookWindowsHookEx(HookHandle);
      HookHandle := 0;
    end;
end;

exports
  DisableTaskKeys, EnableKeyboardCheck;

begin
end.