import { useQuery } from '@tanstack/react-query';
import { useNostr } from '@nostrify/react';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useResolvedDmRelays } from '@/hooks/useDirectMessages';

/**
 * Lightweight DM "envelope" watcher — the id and timestamp of every NIP-17 gift
 * wrap addressed to the user, **without decrypting anything**.
 *
 * This is what makes DM notifications possible without ever prompting Amber:
 * the seal/rumor are encrypted, so we only see that *something* arrived. No
 * sender, no content, no signer round-trip. The preview is intentionally generic
 * ("New direct message") — the honest ceiling when we refuse to decrypt in the
 * background.
 *
 * NIP-17 randomises the outer wrap timestamp (up to 2 days in the past), so we
 * cannot reliably tell "new" from `created_at`. Callers should diff on the
 * stable `id` instead.
 */

const GIFT_WRAP_KIND = 1059;

export interface DmEnvelope {
  id: string;
  createdAt: number;
}

export function useDmEnvelopes(enabled: boolean) {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const { relays, key } = useResolvedDmRelays();

  return useQuery({
    queryKey: ['dm-envelopes', user?.pubkey, key],
    enabled: enabled && !!user?.pubkey && relays.length > 0,
    staleTime: 60_000,
    refetchInterval: 90_000,
    queryFn: async (c): Promise<DmEnvelope[]> => {
      const pubkey = user!.pubkey;
      const batches = await Promise.all(
        relays.map(async (relayUrl) => {
          try {
            const relay = nostr.relay(relayUrl);
            return await relay.query(
              [{ kinds: [GIFT_WRAP_KIND], '#p': [pubkey], limit: 60 }],
              { signal: AbortSignal.any([c.signal, AbortSignal.timeout(8000)]) },
            );
          } catch {
            // One relay failing must not stop the others.
            return [];
          }
        }),
      );

      const unique = new Map<string, number>();
      for (const event of batches.flat()) unique.set(event.id, event.created_at);
      return [...unique].map(([id, createdAt]) => ({ id, createdAt }));
    },
  });
}