import { getAllPosts } from "@/lib/devblog";
import { SITE_URL } from "@/lib/site";

const SITE_TITLE = "Highland Games Studio — Devblog";
const SITE_DESCRIPTION =
  "Behind-the-scenes updates, design decisions, and milestones from Highland Games Studio.";

function escapeXml(input: string): string {
  return input
    .replace(/&/g, "&")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&apos;");
}

export async function GET() {
  const posts = getAllPosts();
  const lastBuildDate = new Date().toUTCString();
  const latest = posts[0];
  const pubDate = latest
    ? new Date(latest.date).toUTCString()
    : lastBuildDate;

  const items = posts
    .map((post) => {
      const url = `${SITE_URL}/devblog/${post.slug}`;
      return `
    <item>
      <title>${escapeXml(post.title)}</title>
      <link>${url}</link>
      <guid isPermaLink="true">${url}</guid>
      <pubDate>${new Date(post.date).toUTCString()}</pubDate>
      ${post.author ? `<author>${escapeXml(post.author)}</author>` : ""}
      <description>${escapeXml(post.excerpt || "")}</description>
    </item>`;
    })
    .join("");

  const xml = `<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
  <channel>
    <title>${escapeXml(SITE_TITLE)}</title>
    <link>${SITE_URL}/devblog</link>
    <description>${escapeXml(SITE_DESCRIPTION)}</description>
    <language>en</language>
    <lastBuildDate>${lastBuildDate}</lastBuildDate>
    <pubDate>${pubDate}</pubDate>
    <atom:link href="${SITE_URL}/feed.xml" rel="self" type="application/rss+xml" />${items}
  </channel>
</rss>`;

  return new Response(xml, {
    headers: {
      "Content-Type": "application/rss+xml; charset=utf-8",
      "Cache-Control": "public, max-age=0, s-maxage=3600, stale-while-revalidate=86400",
    },
  });
}