SkateSpots/src/hooks/useCrewGoal.ts

import { useQuery } from '@tanstack/react-query';
import { useNostr } from '@nostrify/react';
import { nip57 } from 'nostr-tools';
import type { NostrEvent } from '@nostrify/nostrify';
import { ZAP_GOAL_KIND } from '@/lib/types';

export interface CrewGoal {
  id: string;
  pubkey: string;
  /** Human-readable goal description (content). */
  description: string;
  /** Target amount in sats. */
  targetSats: number;
  /** Total raised so far in sats (tallied from zap receipts). */
  raisedSats: number;
  /** Number of contributions. */
  contributions: number;
  /** Optional deadline (unix seconds). */
  closedAt?: number;
  /** Percentage complete (0–100+, may exceed 100). */
  percent: number;
  image?: string;
  summary?: string;
  event: NostrEvent;
}

/** Sum sats from a set of zap receipts (kind 9735), reusing the bolt11/amount logic. */
function tallyZaps(receipts: NostrEvent[], closedAt?: number): { sats: number; count: number } {
  let sats = 0;
  let count = 0;
  for (const z of receipts) {
    if (closedAt && z.created_at > closedAt) continue; // NIP-75: ignore late zaps

    const amountTag = z.tags.find(([n]) => n === 'amount')?.[1];
    if (amountTag) {
      const ms = parseInt(amountTag, 10);
      if (!Number.isNaN(ms)) {
        sats += Math.floor(ms / 1000);
        count++;
        continue;
      }
    }
    const bolt11 = z.tags.find(([n]) => n === 'bolt11')?.[1];
    if (bolt11) {
      try {
        sats += nip57.getSatoshisAmountFromBolt11(bolt11);
        count++;
        continue;
      } catch {
        // ignore unparseable invoice
      }
    }
  }
  return { sats, count };
}

/**
 * Load a crew's NIP-75 funding goal (kind 9041) and tally its progress from
 * zap receipts (kind 9735) that reference the goal event.
 *
 * The goal is fully transparent & non-custodial: contributors zap the goal, and
 * funds settle to the goal author's own Lightning address. SkateSpots never
 * holds funds — it only reads the public tally.
 */
export function useCrewGoal(goalId?: string) {
  const { nostr } = useNostr();

  return useQuery({
    queryKey: ['crew-goal', goalId],
    enabled: !!goalId,
    staleTime: 60 * 1000,
    refetchInterval: (q) => (q.getObserversCount() > 0 ? 90 * 1000 : false),
    queryFn: async (c): Promise<CrewGoal | null> => {
      if (!goalId) return null;
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(8000)]);

      // Fetch the goal event and its zap receipts in one round-trip.
      const [goalEvents, receipts] = await Promise.all([
        nostr.query([{ kinds: [ZAP_GOAL_KIND], ids: [goalId] }], { signal }),
        nostr.query([{ kinds: [9735], '#e': [goalId], limit: 500 }], { signal }),
      ]);

      const goal = goalEvents[0];
      if (!goal) return null;

      const amountTag = goal.tags.find(([n]) => n === 'amount')?.[1];
      const targetMs = amountTag ? parseInt(amountTag, 10) : 0;
      const targetSats = Number.isNaN(targetMs) ? 0 : Math.floor(targetMs / 1000);

      const closedAtTag = goal.tags.find(([n]) => n === 'closed_at')?.[1];
      const closedAt = closedAtTag ? parseInt(closedAtTag, 10) : undefined;

      const { sats: raisedSats, count } = tallyZaps(receipts, closedAt);
      const percent = targetSats > 0 ? Math.round((raisedSats / targetSats) * 100) : 0;

      return {
        id: goal.id,
        pubkey: goal.pubkey,
        description: goal.content,
        targetSats,
        raisedSats,
        contributions: count,
        closedAt,
        percent,
        image: goal.tags.find(([n]) => n === 'image')?.[1],
        summary: goal.tags.find(([n]) => n === 'summary')?.[1],
        event: goal,
      };
    },
  });
}