import 'server-only';
import type { Metadata } from 'next';
import { notFound } from 'next/navigation';
import { api, ApiError, safe } from '@/lib/api';
import { PATH_TYPES, routes, SITE_NAME, SITE_URL, TYPE_PATH, typeLabel } from '@/lib/site';
import type { EntityDetail } from '@/lib/types';
import { describeEntity } from './entity-page';

/**
 * Load an entity for a typed path (`models`, `companies`, `providers`…). 404 when the API says so or when the entity's
 * type is not accepted under this path (so /tools/<framework-slug> is a 404, not a duplicate canonical URL).
 */
export async function loadEntity(typePath: string, slug: string): Promise<EntityDetail> {
  const def = PATH_TYPES[typePath];
  if (!def) notFound();
  try {
    const d = def.api === 'entities' ? await api.entity(slug) : await api.entityOfType(def.api, slug);
    if (!def.types.includes(d.entity_type)) notFound();
    return d;
  } catch (e) {
    if (e instanceof ApiError && e.notFound) notFound();
    throw e;
  }
}

/** Load for the /explore/<type>/<slug> fallback: any type that has no dedicated path. */
export async function loadAnyEntity(type: string, slug: string): Promise<EntityDetail> {
  try {
    const d = await api.entity(slug);
    if (d.entity_type !== type) notFound();
    return d;
  } catch (e) {
    if (e instanceof ApiError && e.notFound) notFound();
    throw e;
  }
}

export async function entityMetadata(typePath: string, slug: string): Promise<Metadata> {
  const def = PATH_TYPES[typePath];
  const d = def ? await safe(def.api === 'entities' ? api.entity(slug) : api.entityOfType(def.api, slug)) : null;
  if (!d || (def && !def.types.includes(d.entity_type))) return { title: def?.singular ?? 'Entity', robots: { index: false } };
  return buildMetadata(d);
}

export function buildMetadata(d: EntityDetail): Metadata {
  const canonical = routes.entity(d);
  const label = typeLabel(d.entity_type);
  const title = d.organization && d.entity_type === 'model' ? `${d.name} — ${d.organization.name} ${label.toLowerCase()}` : `${d.name} — ${label}`;
  const description = describeEntity(d);
  return {
    title,
    description,
    alternates: { canonical },
    openGraph: { title: `${title} | ${SITE_NAME}`, description, url: `${SITE_URL}${canonical}`, type: 'article', siteName: SITE_NAME },
    twitter: { card: 'summary_large_image', title, description },
  };
}

export function canonicalFor(d: EntityDetail): string {
  return routes.entity(d);
}

export { TYPE_PATH };