import { useMemo } from 'react';
import { getDigiPin, isWithinIndia } from '../core/digipin';

/**
 * Compute a DigiPin code from lat/lng entirely offline (no API call).
 * Returns null if coordinates are outside India's bounds.
 *
 * The calculation is pure math (~0.1ms), so no debouncing is needed
 * even when called on every marker drag event.
 */
export function useDigiPin(lat: number, lng: number): string | null {
  return useMemo(() => {
    if (!isWithinIndia(lat, lng)) return null;
    try {
      return getDigiPin(lat, lng);
    } catch {
      return null;
    }
  }, [lat, lng]);
}