import { useQuery } from '@tanstack/react-query';
import ngeohash from 'ngeohash';
import type { FoodSpot } from '@/lib/types';

const CORS_PROXY = 'https://proxy.shakespeare.diy/?url=';
const OVERPASS_API = 'https://overpass-api.de/api/interpreter';

interface OverpassElement {
  type: string;
  id: number;
  lat?: number;
  lon?: number;
  center?: { lat: number; lon: number };
  tags?: Record<string, string>;
}

function calculateDistance(lat1: number, lon1: number, lat2: number, lon2: number): number {
  const R = 6371; // Earth's radius in km
  const dLat = ((lat2 - lat1) * Math.PI) / 180;
  const dLon = ((lon2 - lon1) * Math.PI) / 180;
  const a =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.cos((lat1 * Math.PI) / 180) *
      Math.cos((lat2 * Math.PI) / 180) *
      Math.sin(dLon / 2) *
      Math.sin(dLon / 2);
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
  return R * c;
}

export function useFoodSpots(geohash: string | undefined, radiusKm = 1) {
  return useQuery({
    queryKey: ['food-spots', geohash, radiusKm],
    queryFn: async () => {
      if (!geohash) return [];

      // Decode geohash to get center coordinates
      const { latitude: centerLat, longitude: centerLon } = ngeohash.decode(geohash);

      // Calculate bounding box for the search area
      const latOffset = radiusKm / 111; // ~111km per degree of latitude
      const lonOffset = radiusKm / (111 * Math.cos((centerLat * Math.PI) / 180));

      const south = centerLat - latOffset;
      const west = centerLon - lonOffset;
      const north = centerLat + latOffset;
      const east = centerLon + lonOffset;

      // Overpass QL query for restaurants, cafes, fast food, etc.
      const query = `
        [out:json][timeout:25];
        (
          node["amenity"~"restaurant|cafe|fast_food|bar|pub|food_court"](${south},${west},${north},${east});
          way["amenity"~"restaurant|cafe|fast_food|bar|pub|food_court"](${south},${west},${north},${east});
        );
        out center;
      `;

      const response = await fetch(CORS_PROXY + encodeURIComponent(OVERPASS_API), {
        method: 'POST',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: `data=${encodeURIComponent(query)}`,
      });

      if (!response.ok) {
        throw new Error('Failed to fetch food spots');
      }

      const data = await response.json();

      const foodSpots: FoodSpot[] = data.elements
        .map((element: OverpassElement) => {
          const lat = element.lat ?? element.center?.lat;
          const lon = element.lon ?? element.center?.lon;
          const tags = element.tags ?? {};

          if (!lat || !lon) return null;

          const distance = calculateDistance(centerLat, centerLon, lat, lon);

          return {
            id: `${element.type}-${element.id}`,
            name: tags.name || 'Unknown',
            lat,
            lng: lon,
            type: tags.amenity || 'restaurant',
            cuisine: tags.cuisine,
            address: [tags['addr:housenumber'], tags['addr:street'], tags['addr:city']]
              .filter(Boolean)
              .join(' '),
            phone: tags.phone,
            website: tags.website,
            openingHours: tags.opening_hours,
            distance,
          };
        })
        .filter(Boolean)
        .sort((a: FoodSpot, b: FoodSpot) => (a.distance ?? Infinity) - (b.distance ?? Infinity));

      return foodSpots as FoodSpot[];
    },
    enabled: !!geohash,
    staleTime: 300000, // 5 minutes
  });
}