import type { Metadata } from 'next';
import { notFound, permanentRedirect } from 'next/navigation';
import { describeModel, ModelPage, type ModelPageParams } from '@/components/entity/model-page';
import { api, ApiError, apiD1, safe } from '@/lib/api';
import { routes, SITE_NAME, SITE_URL } from '@/lib/site';
import type { ModelDetail } from '@/lib/types';

type Params = { params: Promise<{ slug: string }>; searchParams: Promise<ModelPageParams> };

/** `/models/<slug>` accepts models AND artifacts, and resolves folded variants to their canonical model (`redirected_from`). */
export async function loadModelOrArtifact(slug: string): Promise<ModelDetail> {
  try {
    return await apiD1.model(slug);
  } catch (e) {
    if (e instanceof ApiError && e.notFound) notFound();
    throw e;
  }
}

export async function generateMetadata({ params }: Params): Promise<Metadata> {
  const { slug } = await params;
  const d = await safe(apiD1.model(slug));
  if (!d || d.entity_type === 'artifact' || d.slug !== slug) return { title: 'Model', robots: { index: false } };
  const title = `${d.name} — Parameters, Context, Benchmarks & Pricing`;
  const description = describeModel(d);
  const canonical = routes.entity(d);
  return {
    title,
    description,
    alternates: { canonical },
    openGraph: { title: `${title} | ${SITE_NAME}`, description, url: `${SITE_URL}${canonical}`, type: 'article', siteName: SITE_NAME },
    twitter: { card: 'summary_large_image', title, description },
  };
}

export default async function ModelRoute({ params, searchParams }: Params) {
  const { slug } = await params;
  const sp = await searchParams;
  const d = await loadModelOrArtifact(slug);
  // Old URLs keep resolving: artifacts live at /artifacts/<slug>; folded evaluation variants and aliases 308 to the canonical model.
  if (d.entity_type === 'artifact') permanentRedirect(routes.artifact(d.slug));
  if (d.redirected_from || d.slug !== slug) permanentRedirect(routes.entity(d));
  if (d.entity_type !== 'model' && d.entity_type !== 'quantization') notFound();
  const related = await safe(api.entityRelated(d.slug, 10));
  return <ModelPage d={d} canonical={routes.entity(d)} related={related?.items} params={sp} />;
}