import { useQuery } from '@tanstack/react-query';
import { LatLngBounds } from 'leaflet';
import { useMemo } from 'react';
import type { BackendSite } from '@/schemas/backend/site';
import { getNearbySites } from '@/services/sites-api';
import { calculateDistance } from '@/utils/coordinates.ts';

/**
 * Calculate center and radius from map bounds
 */
function boundsToCenterAndRadius(bounds: LatLngBounds): {
  lat: number;
  lng: number;
  radius: number;
} {
  const center = bounds.getCenter();
  const ne = bounds.getNorthEast();
  const sw = bounds.getSouthWest();

  // Calculate radius as the distance from center to corner
  const radius = Math.max(
    calculateDistance(center.lat, center.lng, ne.lat, ne.lng),
    calculateDistance(center.lat, center.lng, sw.lat, sw.lng)
  );

  // Add 20% buffer to ensure we get all sites near the edges
  return {
    lat: center.lat,
    lng: center.lng,
    radius: radius * 1.2,
  };
}

/**
 * Hook to fetch sites within current map bounds
 * This enables viewport-based lazy loading of organizations
 * Optimized with better caching and query key stability
 */
export const useSitesByBounds = (bounds: LatLngBounds | null, enabled: boolean = true) => {
  const queryParams = useMemo(() => {
    if (!bounds) return null;
    const params = boundsToCenterAndRadius(bounds);
    // Round coordinates to reduce query key churn (0.001 degrees ≈ 111m)
    return {
      lat: Math.round(params.lat * 1000) / 1000,
      lng: Math.round(params.lng * 1000) / 1000,
      radius: Math.round(params.radius * 10) / 10, // Round to 0.1km
    };
  }, [bounds]);

  return useQuery({
    queryKey: ['sites', 'nearby', queryParams?.lat, queryParams?.lng, queryParams?.radius],
    queryFn: () => {
      if (!queryParams) return Promise.resolve([]);
      return getNearbySites({
        lat: queryParams.lat,
        lng: queryParams.lng,
        radius: queryParams.radius,
      });
    },
    enabled: enabled && !!queryParams,
    placeholderData: [], // Render immediately with empty array - don't block on API
    staleTime: 60 * 1000, // 1 minute - sites don't change often
    gcTime: 10 * 60 * 1000, // 10 minutes - keep in cache longer
    refetchOnWindowFocus: false, // Don't refetch on window focus
    refetchOnMount: false, // Don't refetch if data exists
    retry: 1, // Only retry once on failure
  });
};

/**
 * Create a map of organization ID -> sites for organizations in viewport
 */
export const useOrganizationSitesByBounds = (
  bounds: LatLngBounds | null,
  enabled: boolean = true
) => {
  const { data: sites, isLoading } = useSitesByBounds(bounds, enabled);

  const orgSitesMap = useMemo(() => {
    const map = new Map<string, BackendSite[]>();
    if (!sites) return map;

    sites.forEach((site) => {
      const orgId = site.OwnerOrganizationID;
      if (!orgId) return;

      const existing = map.get(orgId) || [];
      map.set(orgId, [...existing, site]);
    });

    return map;
  }, [sites]);

  return {
    orgSitesMap,
    sites: sites || [],
    isLoading,
  };
};