import { useState, useEffect, useCallback } from 'react';
import { Platform, PermissionsAndroid, Alert } from 'react-native';
import Geolocation from '@react-native-community/geolocation';

interface UserLocation {
  latitude: number;
  longitude: number;
}

interface UseUserLocationResult {
  location: UserLocation | null;
  loading: boolean;
  error: string | null;
  refresh: () => void;
}

/**
 * Hook to get and manage the user's current GPS location.
 * Handles permissions for both Android and iOS.
 */
export const useUserLocation = (): UseUserLocationResult => {
  const [location, setLocation] = useState<UserLocation | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const requestPermission = useCallback(async (): Promise<boolean> => {
    if (Platform.OS === 'ios') {
      // iOS permission is handled via Info.plist; Geolocation auto-prompts
      return true;
    }

    try {
      const granted = await PermissionsAndroid.request(
        PermissionsAndroid.PERMISSIONS.ACCESS_FINE_LOCATION,
        {
          title: 'Location Permission',
          message: 'BankCBS needs access to your location to find nearby branches.',
          buttonPositive: 'Allow',
          buttonNegative: 'Deny',
        },
      );
      return granted === PermissionsAndroid.RESULTS.GRANTED;
    } catch {
      return false;
    }
  }, []);

  const fetchLocation = useCallback(async () => {
    setLoading(true);
    setError(null);

    const hasPermission = await requestPermission();

    if (!hasPermission) {
      setError('Location permission denied');
      setLoading(false);
      // Fallback to a default location (Bengaluru) for demo purposes
      setLocation({ latitude: 12.9716, longitude: 77.5946 });
      return;
    }

    Geolocation.getCurrentPosition(
      (position) => {
        setLocation({
          latitude: position.coords.latitude,
          longitude: position.coords.longitude,
        });
        setLoading(false);
      },
      (err) => {
        setError(err.message);
        setLoading(false);
        // Fallback to a default location for demo purposes
        setLocation({ latitude: 12.9716, longitude: 77.5946 });
      },
      {
        enableHighAccuracy: true,
        timeout: 15000,
        maximumAge: 60000,
      },
    );
  }, [requestPermission]);

  useEffect(() => {
    fetchLocation();
  }, [fetchLocation]);

  return { location, loading, error, refresh: fetchLocation };
};