import { useEffect, useRef } from 'react';
import { useSelector } from 'react-redux';
import { selectIsAuthenticated } from '../Redux/Slices/Token';
import NavigationString from '../Constant/NavigationString';
import { resetAndNavigate } from './NavigationService';
import { logger } from '../core/observability/logger';

/**
 * Declarative auth gate: whenever an existing session ends — a 401 clearing
 * the token via the auth/unauthorized event, an explicit logout, or a
 * keychain wipe — reset navigation to Login.
 *
 * Historically a mid-session 401 cleared the token but left the user
 * stranded on an authenticated screen where every request failed silently.
 * Renders nothing; mount once inside the Redux provider.
 */
const AuthSessionGuard = () => {
  const isAuthenticated = useSelector(selectIsAuthenticated);
  const wasAuthenticated = useRef(isAuthenticated);

  useEffect(() => {
    if (wasAuthenticated.current && !isAuthenticated) {
      logger.info('auth', 'session ended — routing to Login');
      resetAndNavigate(NavigationString.Login);
    }
    wasAuthenticated.current = isAuthenticated;
  }, [isAuthenticated]);

  return null;
};

export default AuthSessionGuard;