import type { Metadata } from 'next';
import Link from 'next/link';
import { notFound } from 'next/navigation';
import { DiffViewer } from '@/components/events/diff-viewer';
import { Container, Note } from '@/components/ui/section';
import { api, ApiError } from '@/lib/api';
import { fmtDateTime, fmtInt } from '@/lib/format';
import { routes } from '@/lib/site';

export const revalidate = 3600;
export const metadata: Metadata = { title: 'Snapshot diff', robots: { index: false } };

export default async function SnapshotDiffPage({ params }: { params: Promise<{ id: string; other: string }> }) {
  const { id, other } = await params;
  let d;
  try {
    d = await api.snapshotDiff(id, other);
  } catch (e) {
    if (e instanceof ApiError && e.notFound) notFound();
    throw e;
  }
  return (
    <Container>
      <div className="pb-4 pt-6 md:pt-10">
        <p className="eyebrow">Historical page viewer · semantic diff</p>
        <h1 className="display mt-2 text-[24px] md:text-[32px]">
          v{d.before.version_no} → v{d.after.version_no}
        </h1>
        <div className="mt-3 grid gap-3 sm:grid-cols-2">
          {[d.before, d.after].map((s, i) => (
            <div key={s.id} className="border border-rule p-3 text-sm">
              <p className="eyebrow">{i === 0 ? 'Before' : 'After'}</p>
              <p className="mt-1 font-medium text-ink">{s.title ?? '—'}</p>
              <p className="tnum text-xs text-ink-3">
                {fmtDateTime(s.fetched_at)} · {fmtInt(s.block_count)} blocks · {fmtInt(s.text_length)} chars
              </p>
              <Link href={routes.snapshot(s.id)} className="link text-xs">
                Open version →
              </Link>
            </div>
          ))}
        </div>
        <p className="mt-2 text-xs text-ink-3">
          <Link href={routes.sensor(d.after.sensor_id)} className="link">
            Sensor
          </Link>
        </p>
      </div>
      <DiffViewer diff={d.diff} significance={null} />
      <Note className="mt-6">Computed on demand from the two stored snapshots. Block identities are stable across versions so moved content is not reported as removed + added.</Note>
    </Container>
  );
}