import { useQuery } from '@tanstack/react-query';
import { useNostr } from '@nostrify/react';
import type { NostrEvent } from '@nostrify/nostrify';
import { zapReceiptSats } from '@/hooks/useZapTotals';

export interface ZapLeaderboardTarget {
  /** `a` coordinate (`kind:pubkey:identifier`) or event id. */
  key: string;
  sats: number;
  count: number;
}

export interface ZapLeaderboardSender {
  pubkey: string;
  sats: number;
  count: number;
}

export interface ZapLeaderboard {
  targets: ZapLeaderboardTarget[];
  senders: ZapLeaderboardSender[];
}

/**
 * Aggregate zap receipts into leaderboards.
 *
 * One query for kind-9735 receipts (bounded by `since` for time-ranged boards),
 * then two tallies:
 *  - **targets** — total sats per zapped item (spot/shop/event coordinate).
 *  - **senders** — total sats sent per zapper (taken from the embedded zap
 *    request, since a receipt's own pubkey is the LNURL server, not the sender).
 */
export function useZapLeaderboard(since?: number) {
  const { nostr } = useNostr();

  return useQuery<ZapLeaderboard>({
    queryKey: ['zap-leaderboard', since ?? 'all'],
    staleTime: 5 * 60 * 1000,
    queryFn: async (c): Promise<ZapLeaderboard> => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(12000)]);

      const receipts: NostrEvent[] = await nostr.query(
        [{ kinds: [9735], ...(since ? { since } : {}), limit: 1000 }],
        { signal },
      );

      const targets = new Map<string, { sats: number; count: number }>();
      const senders = new Map<string, { sats: number; count: number }>();

      for (const zap of receipts) {
        const sats = zapReceiptSats(zap);

        const aTag = zap.tags.find(([t]) => t === 'a')?.[1];
        const eTag = zap.tags.find(([t]) => t === 'e')?.[1];
        const target = aTag ?? eTag;
        if (target) {
          const cur = targets.get(target) ?? { sats: 0, count: 0 };
          cur.sats += sats;
          cur.count += 1;
          targets.set(target, cur);
        }

        const description = zap.tags.find(([t]) => t === 'description')?.[1];
        if (description) {
          try {
            const sender = JSON.parse(description)?.pubkey as string | undefined;
            if (sender) {
              const cur = senders.get(sender) ?? { sats: 0, count: 0 };
              cur.sats += sats;
              cur.count += 1;
              senders.set(sender, cur);
            }
          } catch {
            /* malformed zap request — skip */
          }
        }
      }

      return {
        targets: [...targets.entries()]
          .map(([key, v]) => ({ key, ...v }))
          .sort((a, b) => b.sats - a.sats),
        senders: [...senders.entries()]
          .map(([pubkey, v]) => ({ pubkey, ...v }))
          .sort((a, b) => b.sats - a.sats),
      };
    },
  });
}