// RSS 2.0 feed — hand-rolled static endpoint like search.json.js (no @astrojs/rss
// dependency; the spec is 20 lines of XML). Newest 30 items, absolute URLs from
// the configured `site`.
import { getCollection } from 'astro:content';

const esc = (s = '') =>
  s.replace(/[<>&'"]/g, (c) => ({ '<': '&lt;', '>': '&gt;', '&': '&amp;', "'": '&apos;', '"': '&quot;' })[c]);

export async function GET(context) {
  const site = context.site; // always set in astro.config.mjs
  const posts = (await getCollection('news', ({ data }) => !data.draft))
    .sort((a, b) => b.data.date.valueOf() - a.data.date.valueOf())
    .slice(0, 30);

  const items = posts
    .map((p) => {
      const url = new URL(`/news/${p.id}`, site).href;
      return `    <item>
      <title>${esc(p.data.title)}</title>
      <link>${url}</link>
      <guid isPermaLink="true">${url}</guid>
      <pubDate>${p.data.date.toUTCString()}</pubDate>
      <description>${esc(p.data.description)}</description>
      <category>${esc(p.data.category)}</category>
    </item>`;
    })
    .join('\n');

  const xml = `<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
  <channel>
    <title>CTAO Science Portal News</title>
    <link>${new URL('/news', site).href}</link>
    <description>News and announcements of the Cherenkov Telescope Array Observatory</description>
    <language>en</language>
    <lastBuildDate>${(posts[0]?.data.date ?? new Date()).toUTCString()}</lastBuildDate>
    <atom:link href="${new URL('/rss.xml', site).href}" rel="self" type="application/rss+xml"/>
${items}
  </channel>
</rss>
`;
  return new Response(xml, { headers: { 'Content-Type': 'application/rss+xml; charset=utf-8' } });
}