import { useState, useCallback } from 'react';

interface GeoState {
  loading: boolean;
  error: string | null;
}

/**
 * Hook to imperatively request the user's current GPS position.
 * Returns a `locate(onSuccess)` callback to trigger the permission prompt.
 */
export function useGeolocation() {
  const [state, setState] = useState<GeoState>({ loading: false, error: null });

  const locate = useCallback((onSuccess: (lat: number, lng: number) => void) => {
    if (!navigator.geolocation) {
      setState({ loading: false, error: 'Geolocation is not supported by your browser.' });
      return;
    }

    setState({ loading: true, error: null });

    navigator.geolocation.getCurrentPosition(
      ({ coords }) => {
        setState({ loading: false, error: null });
        onSuccess(coords.latitude, coords.longitude);
      },
      (err) => {
        let message = 'Unable to get location.';
        if (err.code === err.PERMISSION_DENIED) {
          message = 'Location permission denied. Please enable it in browser settings.';
        } else if (err.code === err.POSITION_UNAVAILABLE) {
          message = 'Location unavailable. Try again or place the pin manually.';
        } else if (err.code === err.TIMEOUT) {
          message = 'Location request timed out. Try again.';
        }
        setState({ loading: false, error: message });
      },
      { enableHighAccuracy: true, timeout: 12_000, maximumAge: 0 }
    );
  }, []);

  const clearError = useCallback(() => {
    setState((s) => ({ ...s, error: null }));
  }, []);

  return { ...state, locate, clearError };
}