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

import { useSkateRelays } from '@/hooks/useSkateRelays';
import { onlyVerified } from '@/lib/verifyEvents';
import type { NostrEvent } from '@nostrify/nostrify';

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

export interface UserReport {
  id: string;
  /** The reporter. */
  pubkey: string;
  createdAt: number;
  content: string;
  /** NIP-56 reason from the `p` tag, when present. */
  reason?: string;
}

/**
 * Public user-level reports (NIP-56) that name this pubkey in a `p` tag, read
 * from the community relay + the viewer's relays. This is the auditable side of
 * a "flagged" account: the provider asserts a count, but the raw reports are
 * public, so we can show who said it in aggregate.
 */
export function useUserReports(pubkey: string | undefined) {
  const { querySkateContent, getQueryKeySuffix } = useSkateRelays();

  const query = useQuery({
    queryKey: ['user-reports', pubkey, getQueryKeySuffix()],
    enabled: !!pubkey,
    staleTime: 60_000,
    queryFn: async (c): Promise<UserReport[]> => {
      if (!pubkey) return [];
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(8000)]);
      const events = onlyVerified(await querySkateContent(
        [{ kinds: [REPORT_KIND], '#p': [pubkey], limit: 200 }],
        { signal },
      ));
      return events.map(toUserReport).filter((r): r is UserReport => r !== null);
    },
  });

  const reporters = useMemo(() => {
    const set = new Set<string>();
    for (const report of query.data ?? []) set.add(report.pubkey);
    return [...set];
  }, [query.data]);

  return {
    reports: query.data ?? [],
    reporterPubkeys: reporters,
    /** Distinct reporters — the anti-brigade unit, same as content reports. */
    reporterCount: reporters.length,
    isLoading: query.isLoading,
  };
}

function toUserReport(event: NostrEvent): UserReport | null {
  const pTag = event.tags.find(([name]) => name === 'p');
  if (!pTag) return null;
  return {
    id: event.id,
    pubkey: event.pubkey,
    createdAt: event.created_at,
    content: event.content,
    reason: pTag[2],
  };
}