import { useEffect, useState } from 'react';
import type { ServiceAlert } from '@/lib/ridebus';
import { getActiveAlerts, watchAlertValidity } from '@/lib/serviceAlerts';

export function useActiveAlerts(alerts: ServiceAlert[], cityId: number) {
  const [now, setNow] = useState(Date.now);
  useEffect(() => {
    const refresh = () => setNow(Date.now());
    const refreshVisible = () => {
      if (document.visibilityState === 'visible') refresh();
    };
    const stopWatching = watchAlertValidity(alerts, refresh);
    document.addEventListener('visibilitychange', refreshVisible);
    window.addEventListener('focus', refresh);
    return () => {
      stopWatching();
      document.removeEventListener('visibilitychange', refreshVisible);
      window.removeEventListener('focus', refresh);
    };
  }, [alerts]);
  return getActiveAlerts(alerts, cityId, now);
}