function createTodayLockScreen({
  storage,
  getLogin,
  serviceWorker,
  NotificationRef,
  control,
  status,
  locationRef,
  historyRef,
  onAction = () => {},
}) {
  const preferenceKey = () => {
    const login = String(getLogin?.() || '').trim().toLowerCase();
    return login ? 'stackchain.today-lock-screen.v1.' + encodeURIComponent(login) : '';
  };
  const supported = Boolean(serviceWorker && NotificationRef);
  const enabled = () => {
    const key = preferenceKey();
    return Boolean(key && storage?.getItem(key) === '1');
  };
  const setStatus = message => {
    if (status) status.textContent = message;
  };
  const post = async message => {
    const target = serviceWorker?.controller || (await serviceWorker?.ready)?.active;
    target?.postMessage?.(message);
  };
  const hide = () => post({
    type:'stackchain-today-lock-screen', active:false, running:false,
  });
  const render = () => {
    if (control) {
      control.checked = enabled();
      control.disabled = !supported;
    }
    if (!supported) setStatus('Lock-screen controls are not supported on this device.');
    else if (enabled()) setStatus('Lock-screen Today controls are on.');
  };
  const consumeAction = action => {
    if (!enabled() || !['pause', 'resume'].includes(action)) return false;
    onAction(action);
    return true;
  };
  const api = {
    enabled,
    async enable() {
      if (!supported) {
        render();
        return false;
      }
      const permission = NotificationRef.permission === 'granted' ?
        'granted' : await NotificationRef.requestPermission();
      if (permission !== 'granted') {
        if (control) control.checked = false;
        setStatus(permission === 'denied' ?
          'Lock-screen controls are blocked in browser settings.' :
          'Lock-screen controls were not enabled.');
        return false;
      }
      const key = preferenceKey();
      if (!key) return false;
      storage?.setItem(key, '1');
      render();
      return true;
    },
    async disable() {
      const key = preferenceKey();
      if (key) storage?.removeItem(key);
      if (control) control.checked = false;
      setStatus('Lock-screen Today controls are off.');
      await hide();
      return true;
    },
    async sync(snapshot, active) {
      if (!enabled() || NotificationRef?.permission !== 'granted') return false;
      const visible = Boolean(active && snapshot?.identity);
      await post({
        type:'stackchain-today-lock-screen',
        active:visible,
        running:visible && Boolean(snapshot.running),
      });
      return true;
    },
    consumeLaunchAction() {
      let url;
      try { url = new URL(locationRef?.href || ''); }
      catch (_error) { return false; }
      const action = url.searchParams.get('today_timer_action');
      if (!['pause', 'resume'].includes(action)) return false;
      url.searchParams.delete('today_timer_action');
      historyRef?.replaceState?.(null, '', url.pathname + url.search + url.hash);
      return consumeAction(action);
    },
    render,
  };
  control?.addEventListener?.('change', () => {
    if (control.checked) api.enable();
    else api.disable();
  });
  serviceWorker?.addEventListener?.('message', event => {
    if (event.data?.type === 'stackchain-today-timer-action') consumeAction(String(event.data.action || ''));
  });
  render();
  return api;
}

if (typeof module !== 'undefined' && module.exports) module.exports = createTodayLockScreen;