/*
 * A second sitemap for the URLs Next owns.
 *
 * /sitemap.xml is proxied from FastAPI (app/(frontend)/sitemap.xml), which
 * knows nothing about Payload — the backend and frontend ship as separate
 * images. Rather than teach it, the Next-owned URLs get their own sitemap and
 * robots.txt lists both.
 */
import { getCachedPayload } from '@/lib/payload';
import { absoluteUrl } from '@/lib/site';

/*
 * Dynamic, not ISR.
 *
 * This route has no dynamic params, so Next prerenders it at build time — and
 * CI builds the image with no database reachable, which fails the build. It is
 * a single indexed query against Postgres on the same Docker network, so
 * rendering per request is cheap, and it means a newly published post appears
 * here immediately rather than waiting on a revalidation.
 */
export const dynamic = 'force-dynamic';

export async function GET() {
  const payload = await getCachedPayload();
  const { docs } = await payload.find({
    collection: 'posts',
    where: { _status: { equals: 'published' } },
    sort: '-publishedAt',
    limit: 500,
    depth: 0,
  });

  const urls: Array<{ loc: string; lastmod: string | null }> = [
    { loc: absoluteUrl('/about'), lastmod: null },
    { loc: absoluteUrl('/blog'), lastmod: null },
    ...docs.map((post) => ({
      loc: absoluteUrl(`/blog/${post.slug}`),
      lastmod: new Date(String(post.updatedAt ?? post.publishedAt)).toISOString(),
    })),
  ];

  const xml = `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
${urls.map(({ loc, lastmod }) =>
  `  <url><loc>${loc}</loc>${lastmod ? `<lastmod>${lastmod}</lastmod>` : ''}</url>`,
).join('\n')}
</urlset>`;

  return new Response(xml, {
    headers: { 'Content-Type': 'application/xml; charset=utf-8' },
  });
}