import { useQuery } from '@tanstack/react-query';
import { useNostr } from '@nostrify/react';
import { useCurrentUser } from './useCurrentUser';
import { onlyVerified } from '@/lib/verifyEvents';

/**
 * Hook to fetch trust scores for multiple pubkeys in batch.
 * More efficient than calling useTrustScore multiple times.
 * 
 * @param pubkeys - Array of pubkeys to calculate trust scores for
 * @returns Map of pubkey to trust score (0-100)
 */
export function useBatchTrustScores(pubkeys: string[]) {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();

  return useQuery({
    queryKey: ['batch-trust-scores', pubkeys.sort().join(','), user?.pubkey],
    queryFn: async (c) => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(8000)]);
      const scores = new Map<string, number>();

      try {
        // Get user's follow list (kind 3)
        const sourcePubkey = user?.pubkey || '20e7c953439e66f3882ab96fe0faa8ba246d6fb12c03b0cb4e2dc4623b8bcb21';
        
        const followListEvents = onlyVerified(await nostr.query(
          [{ kinds: [3], authors: [sourcePubkey], limit: 1 }],
          { signal }
        ));

        const followList = followListEvents[0];
        if (!followList) {
          // No follow list (e.g. logged-out or new account) — default all to 0.
          pubkeys.forEach((pk) => scores.set(pk, 0));
          return scores;
        }

        // Extract followed pubkeys
        const following = new Set(
          followList.tags
            .filter(([tag]) => tag === 'p')
            .map(([, pubkey]) => pubkey)
        );

        // Process each pubkey
        for (const targetPubkey of pubkeys) {
          // Self score = 100
          if (user?.pubkey && targetPubkey === user.pubkey) {
            scores.set(targetPubkey, 100);
            continue;
          }

          // Direct follow = 90
          if (following.has(targetPubkey)) {
            scores.set(targetPubkey, 90);
            continue;
          }

          // Default to 0 (will check friend-of-friend and NIP-05 later)
          scores.set(targetPubkey, 0);
        }

        // Get friend-of-friend relationships (batch query)
        const uncheckedPubkeys = pubkeys.filter((pk) => scores.get(pk) === 0);
        
        if (uncheckedPubkeys.length > 0) {
          const friendsFollowLists = onlyVerified(await nostr.query(
            [{ kinds: [3], authors: Array.from(following), limit: 100 }],
            { signal }
          ));

          // Build a set of all friends-of-friends
          const friendsOfFriends = new Set<string>();
          for (const friendList of friendsFollowLists) {
            friendList.tags
              .filter(([tag]) => tag === 'p')
              .forEach(([, pubkey]) => friendsOfFriends.add(pubkey));
          }

          // Check friend-of-friend = 60
          for (const pubkey of uncheckedPubkeys) {
            if (friendsOfFriends.has(pubkey)) {
              scores.set(pubkey, 60);
            }
          }
        }

        // Check NIP-05 verification for remaining 0-score pubkeys
        const unverifiedPubkeys = pubkeys.filter((pk) => scores.get(pk) === 0);
        
        if (unverifiedPubkeys.length > 0) {
          const profileEvents = onlyVerified(await nostr.query(
            [{ kinds: [0], authors: unverifiedPubkeys }],
            { signal }
          ));

          for (const profileEvent of profileEvents) {
            try {
              const metadata = JSON.parse(profileEvent.content);
              if (metadata.nip05) {
                scores.set(profileEvent.pubkey, 30);
              }
            } catch {
              // Ignore JSON parse errors
            }
          }
        }

        return scores;
      } catch (error) {
        console.warn('[useBatchTrustScores] Error calculating batch trust scores:', error);
        // Return default scores of 0
        pubkeys.forEach((pk) => scores.set(pk, 0));
        return scores;
      }
    },
    enabled: pubkeys.length > 0,
    staleTime: 3600000, // Cache for 1 hour
    gcTime: 86400000, // Keep in cache for 24 hours
    retry: 1,
  });
}