/**
 * VerifyCardPage — /verify/:naddr
 *
 * Anyone can open this (scan the QR on a printed card) to check a Park Access
 * Card or Rider Card: it fetches the event, verifies the signature, and — for a
 * park pass — confirms the issuer really owns the venue it names.
 *
 * It is intentionally honest about what it does and does NOT prove.
 */
import { useParams, Link } from 'react-router-dom';
import { useQuery } from '@tanstack/react-query';
import { nip19, verifyEvent } from 'nostr-tools';
import { useSeoMeta } from '@unhead/react';
import { BadgeCheck, ShieldAlert, ShieldX, Loader2, ExternalLink, MapPin } from 'lucide-react';

import { useNostr } from '@/hooks/useNostr';
import { useAuthor } from '@/hooks/useAuthor';
import { useTranslation } from '@/contexts/language';
import { genUserName } from '@/lib/genUserName';
import { RIDER_CARD_KIND, PARK_ACCESS_CARD_KIND } from '@/lib/riderCard';
import { SKATE_SPOT_KIND } from '@/lib/types';
import type { NostrEvent } from '@nostrify/nostrify';

interface ParsedNaddr {
  kind: number;
  pubkey: string;
  identifier: string;
  relays: string[];
}

function parseNaddr(value: string): ParsedNaddr | null {
  try {
    const d = nip19.decode(value);
    if (d.type !== 'naddr') return null;
    const { kind, pubkey, identifier, relays } = d.data;
    return { kind, pubkey, identifier, relays: relays ?? [] };
  } catch {
    return null;
  }
}

export default function VerifyCardPage() {
  const { t } = useTranslation();
  const { naddr = '' } = useParams<{ naddr: string }>();
  const { nostr } = useNostr();
  const parsed = parseNaddr(naddr);

  useSeoMeta({ title: 'Verify a card — SkateSpots', description: 'Verify a SkateSpots Rider Card or Park Access Card.' });

  const result = useQuery({
    queryKey: ['verify-card', naddr],
    enabled: !!parsed,
    staleTime: 60_000,
    queryFn: async (c) => {
      if (!parsed) return { status: 'notfound' as const };
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(8000)]);
      const events = await nostr.query(
        [{ kinds: [parsed.kind], authors: [parsed.pubkey], '#d': [parsed.identifier], limit: 1 }],
        { signal },
      );
      const event = events[0] as NostrEvent | undefined;
      if (!event) return { status: 'notfound' as const };
      if (!verifyEvent(event)) return { status: 'invalid' as const };

      // Park pass — confirm the issuer owns the venue it names, when it names one.
      let venue: { status: 'none' | 'verified' | 'mismatch'; title?: string; coord?: string } = { status: 'none' };
      if (event.kind === PARK_ACCESS_CARD_KIND) {
        const aTag = event.tags.find(([n]) => n === 'a')?.[1];
        if (aTag) {
          venue = { status: 'mismatch', coord: aTag };
          const [k, pk, dTag] = aTag.split(':');
          if (k === String(SKATE_SPOT_KIND) && pk && dTag) {
            try {
              const spots = await nostr.query(
                [{ kinds: [SKATE_SPOT_KIND], authors: [pk], '#d': [dTag], limit: 1 }],
                { signal },
              );
              const spot = spots[0] as NostrEvent | undefined;
              if (spot) {
                venue = { status: spot.pubkey === event.pubkey ? 'verified' : 'mismatch', title: spot.tags.find(([n]) => n === 'title')?.[1] || spot.tags.find(([n]) => n === 'name')?.[1], coord: aTag };
              }
            } catch { /* leave mismatch */ }
          }
        }
      }

      return { status: 'valid' as const, event, venue };
    },
  });

  const author = useAuthor(parsed?.pubkey ?? '');
  const issuerName = author.data?.metadata?.name ?? (parsed ? genUserName(parsed.pubkey) : '');

  const data = result.data;
  const valid = data && data.status === 'valid' ? data : undefined;
  const event = valid?.event;
  const venue = valid?.venue;

  return (
    <div className="max-w-lg mx-auto px-4 py-10">
      <div className="text-center mb-6">
        <h1 className="text-3xl font-black uppercase tracking-tight">
          <span className="neon-red">VERIFY</span> <span className="text-white">CARD</span>
        </h1>
      </div>

      {!parsed && (
        <StatusCard tone="warn" icon={<ShieldAlert className="h-10 w-10" />} title={t('cardUi.verify.notFound')} body={t('cardUi.verify.notFoundDesc')} />
      )}

      {parsed && result.isLoading && (
        <div className="flex items-center justify-center gap-2 py-16 text-gray-400">
          <Loader2 className="h-5 w-5 animate-spin" /> {t('cardUi.verify.checking')}
        </div>
      )}

      {parsed && !result.isLoading && data?.status === 'notfound' && (
        <StatusCard tone="warn" icon={<ShieldAlert className="h-10 w-10" />} title={t('cardUi.verify.notFound')} body={t('cardUi.verify.notFoundDesc')} />
      )}

      {parsed && data?.status === 'invalid' && (
        <StatusCard tone="bad" icon={<ShieldX className="h-10 w-10" />} title={t('cardUi.verify.invalid')} body={t('cardUi.verify.invalidDesc')} />
      )}

      {event && (
        <>
          <StatusCard tone="good" icon={<BadgeCheck className="h-10 w-10" />} title={t('cardUi.verify.authentic')} body={t('cardUi.verify.authenticDesc')} />

          <div className="mt-5 rounded-2xl border border-white/10 bg-black/40 divide-y divide-white/5">
            <Row label={t('cardUi.verify.kind')} value={event.kind === PARK_ACCESS_CARD_KIND ? t('cardUi.verify.kindPark') : t('cardUi.verify.kindRider')} />
            <Row label={t('cardUi.verify.issuedBy')} value={issuerName} />
            {event.kind === PARK_ACCESS_CARD_KIND && (
              <>
                <Row label={t('cardUi.verify.accessLevel')} value={event.tags.find(([n]) => n === 'access-level')?.[1] ?? '—'} />
                {event.tags.find(([n]) => n === 'valid-thru')?.[1] && (
                  <Row label={t('cardUi.verify.validThru')} value={event.tags.find(([n]) => n === 'valid-thru')?.[1] ?? ''} />
                )}
              </>
            )}
            {event.kind === RIDER_CARD_KIND && (
              <Row label={t('cardUi.verify.selfIssued')} value={t('cardUi.verify.selfIssuedDesc')} />
            )}
          </div>

          {/* Venue binding (park passes) */}
          {event.kind === PARK_ACCESS_CARD_KIND && venue && (
            <div className="mt-4 rounded-2xl border border-white/10 bg-black/40 p-4 flex items-start gap-3">
              <MapPin className="h-5 w-5 text-gray-400 mt-0.5 flex-shrink-0" />
              <div className="text-sm">
                <div className="font-bold text-white">{t('cardUi.verify.venue')}</div>
                {venue.status === 'verified' && (
                  <div className="text-green-400 mt-0.5">✓ {t('cardUi.verify.venueVerified', { name: venue.title ?? '' })}</div>
                )}
                {venue.status === 'mismatch' && (
                  <div className="text-amber-400 mt-0.5">{t('cardUi.verify.venueMismatch')}</div>
                )}
                {venue.status === 'none' && (
                  <div className="text-gray-400 mt-0.5">{t('cardUi.verify.venueNone')}</div>
                )}
              </div>
            </div>
          )}

          <div className="mt-6 flex flex-col gap-2">
            {parsed && (
              <Link to={`/card/${nip19.npubEncode(parsed.pubkey)}`} className="text-center text-sm text-[#ccff00] hover:underline inline-flex items-center justify-center gap-1.5">
                {t('cardUi.verify.viewCard')} <ExternalLink className="h-3.5 w-3.5" />
              </Link>
            )}
            <p className="text-[11px] text-gray-600 text-center mt-1">{t('cardUi.verify.disclaimer')}</p>
          </div>
        </>
      )}
    </div>
  );
}

function StatusCard({ tone, icon, title, body }: { tone: 'good' | 'warn' | 'bad'; icon: React.ReactNode; title: string; body: string }) {
  const ring = tone === 'good' ? 'border-green-500/40 bg-green-500/5 text-green-400'
    : tone === 'warn' ? 'border-amber-500/40 bg-amber-500/5 text-amber-400'
      : 'border-red-500/40 bg-red-500/5 text-red-400';
  return (
    <div className={`rounded-2xl border ${ring} p-6 text-center`}>
      <div className="flex justify-center mb-3">{icon}</div>
      <div className="text-lg font-black uppercase tracking-wide">{title}</div>
      <p className="text-sm text-gray-300 mt-2">{body}</p>
    </div>
  );
}

function Row({ label, value }: { label: string; value: string }) {
  return (
    <div className="flex items-center justify-between gap-4 px-4 py-3">
      <span className="text-[11px] uppercase tracking-widest text-gray-500">{label}</span>
      <span className="text-sm font-bold text-white text-right">{value}</span>
    </div>
  );
}