import { useMemo } from 'react';
import { useQuery } from '@tanstack/react-query';
import { useSkateRelays } from '@/hooks/useSkateRelays';

/** NIP-56 report kind. */
export const REPORT_KIND = 1984;

export interface SpotReportCounts {
  /** Every NIP-56 report referencing the spot. */
  total: number;
  /** Reports specifically tagged `not-a-skate-spot` (see useNotASpotReport). */
  notASpot: number;
  /** DISTINCT accounts that filed a `not-a-skate-spot` report (anti-brigade). */
  reporters: number;
}

/**
 * Batch-read NIP-56 reports for many spots in ONE query.
 *
 * Reports carry the target's event id in an `e` tag, so asking for
 * `#e: [all spot ids]` is a single relay request — the same trick as the status
 * and photo batch hooks.
 *
 * WHY THIS EXISTS: people could already report a spot, but nothing ever brought
 * those reports to the admin — the only reader in the whole app was a count on
 * marketplace cards. A report button whose output nobody sees is decoration, so
 * the review queue now ranks reported spots to the top.
 */
export function useSpotReports(spots: Array<{ id: string }>) {
  const { querySkateContent, getQueryKeySuffix } = useSkateRelays();

  const ids = useMemo(() => spots.map((s) => s.id).filter(Boolean), [spots]);

  const query = useQuery({
    queryKey: ['spot-reports', ids.slice().sort().join(','), getQueryKeySuffix()],
    enabled: ids.length > 0,
    staleTime: 60_000,
    queryFn: async (c) => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(8000)]);
      return querySkateContent(
        [{ kinds: [REPORT_KIND], '#e': ids, limit: 1000 }],
        { signal },
      );
    },
  });

  const counts = useMemo(() => {
    const map = new Map<string, SpotReportCounts>();
    const notASpotReporters = new Map<string, Set<string>>();
    for (const ev of query.data ?? []) {
      // Our own taxonomy marker, or the NIP-56 'other' reason from the dialog.
      const isNotASpot =
        ev.tags.some(([t, v]) => t === 't' && v === 'not-a-skate-spot') ||
        ev.tags.some(([t, v]) => t === 'l' && v === 'not-a-skate-spot');
      // A report can reference several targets; count each.
      for (const [n, value] of ev.tags) {
        if (n !== 'e' || !value) continue;
        const entry = map.get(value) ?? { total: 0, notASpot: 0, reporters: 0 };
        entry.total += 1;
        if (isNotASpot) {
          entry.notASpot += 1;
          const set = notASpotReporters.get(value) ?? new Set<string>();
          set.add(ev.pubkey);
          notASpotReporters.set(value, set);
          entry.reporters = set.size;
        }
        map.set(value, entry);
      }
    }
    return map;
  }, [query.data]);

  return {
    isLoading: query.isLoading,
    getCounts: (id: string): SpotReportCounts =>
      counts.get(id) ?? { total: 0, notASpot: 0, reporters: 0 },
  };
}