import { useQuery } from '@tanstack/react-query';
import { useSkateRelays } from '@/hooks/useSkateRelays';
import { APP_DATA_KIND, NEWSLETTER_SUB_D } from '@/lib/types';

/**
 * A best-effort community tally of newsletter subscribers.
 *
 * Each subscriber owns a public NIP-78 marker (kind 30078, d=NEWSLETTER_SUB_D)
 * with a `subscribed` boolean tag. We query those markers and count the ones
 * currently set to "true", deduped by author (one vote per pubkey).
 *
 * This is intentionally approximate — relays only return what they hold — so we
 * present it as social proof ("N+ skaters"), not an exact figure.
 */
export function useNewsletterSubscriberCount() {
  const { querySkateContent, getQueryKeySuffix } = useSkateRelays();

  return useQuery({
    queryKey: ['newsletter-subscriber-count', getQueryKeySuffix()],
    staleTime: 5 * 60 * 1000,
    gcTime: 30 * 60 * 1000,
    queryFn: async (c): Promise<number> => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(6000)]);
      const events = await querySkateContent(
        [{ kinds: [APP_DATA_KIND], '#d': [NEWSLETTER_SUB_D], limit: 1000 }],
        { signal },
      );

      // Keep the newest marker per author, then count the "true" ones.
      const latestByAuthor = new Map<string, { subscribed: boolean; createdAt: number }>();
      for (const ev of events) {
        const subscribed = ev.tags.find(([n]) => n === 'subscribed')?.[1] === 'true';
        const existing = latestByAuthor.get(ev.pubkey);
        if (!existing || ev.created_at > existing.createdAt) {
          latestByAuthor.set(ev.pubkey, { subscribed, createdAt: ev.created_at });
        }
      }

      let count = 0;
      for (const { subscribed } of latestByAuthor.values()) {
        if (subscribed) count++;
      }
      return count;
    },
  });
}