import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { useTradeReputation } from '@/hooks/useTradeAttestations';
import { useBatchTrustScores } from '@/hooks/useBatchTrustScores';
import { cn } from '@/lib/utils';
import { Handshake } from 'lucide-react';

function Stat({ label, value, accent }: { label: string; value: number; accent?: boolean }) {
  return (
    <div className="rounded-lg border border-white/10 bg-white/[0.03] px-2 py-3">
      <p className={cn('text-xl font-black', accent ? 'text-[#ccff00]' : 'text-white')}>{value}</p>
      <p className="text-[10px] uppercase tracking-wide text-gray-500">{label}</p>
    </div>
  );
}

/**
 * Marketplace reputation for a profile, derived from mutually-signed trade
 * attestations (kind 31871, see NIP.md → Trade Attestations).
 *
 * "Verified" is the strong signal: the seller AND the counterparty both signed
 * an attestation for the same listing. Renders nothing when there are no trades.
 */
export function TradeReputationCard({ pubkey, className }: { pubkey: string; className?: string }) {
  const { data } = useTradeReputation(pubkey);
  const verifiedWith = data?.verifiedWith ?? [];
  // Trust-weight each mutually-confirmed trade by the counterparty's web-of-trust
  // score, so a ring of fresh accounts can't inflate reputation.
  const { data: scores } = useBatchTrustScores(verifiedWith.map((v) => v.pubkey));

  const total = (data?.sales ?? 0) + (data?.purchases ?? 0);
  if (!data || total === 0) return null;

  const people = data.verifiedCounterparties;
  // Cap each counterparty's contribution at 3 so one partner — or a colluding
  // pair confirming each other over and over — can't inflate the score.
  const weighted = verifiedWith.reduce(
    (sum, v) => sum + Math.min(v.count, 3) * ((scores?.get(v.pubkey) ?? 0) / 100),
    0,
  );
  const trustLabel =
    weighted >= 5 ? 'Highly trusted trader' : weighted >= 1 ? 'Building reputation' : 'New trader';
  // The classic fake-reputation pattern: several "trades", all with one account.
  const singlePartnerWarning = data.verified >= 3 && people <= 1;

  return (
    <Card className={cn('bg-black/90 border-2 border-[#ff6600]/25', className)}>
      <CardHeader className="pb-3">
        <CardTitle className="flex items-center gap-2 text-lg text-[#ff6600]">
          <Handshake className="h-5 w-5" />
          Trades
        </CardTitle>
      </CardHeader>
      <CardContent className="space-y-3">
        <div className="grid grid-cols-3 gap-2 text-center">
          <Stat label="Verified" value={data.verified} accent />
          <Stat label="Sales" value={data.sales} />
          <Stat label="Purchases" value={data.purchases} />
        </div>
        <p className="text-xs text-gray-500">
          {data.verified > 0
            ? `${data.verified} mutually-confirmed ${data.verified === 1 ? 'trade' : 'trades'} with ${people} ${people === 1 ? 'person' : 'people'}`
            : 'Awaiting mutual confirmation'}
        </p>
        {singlePartnerWarning && (
          <p className="rounded-md border border-amber-500/30 bg-amber-500/10 px-2 py-1.5 text-xs text-amber-300">
            ⚠ Every confirmation is with the same account. Mutual confirmation is
            self-reported, so treat this record with care.
          </p>
        )}
        {data.verified > 0 && (
          <p className="text-xs text-gray-500">
            Trust-weighted <span className="font-bold text-[#ccff00]">{weighted.toFixed(1)}</span>
            {' · '}
            {trustLabel}
          </p>
        )}
        <p className="text-[10px] leading-tight text-gray-600">
          Self-reported and mutually signed — a signal, not proof of payment.
        </p>
      </CardContent>
    </Card>
  );
}