// generate sitemap index as suggested here https://github.com/vercel/next.js/discussions/61025

import { generateSitemaps } from "@/app/sitemap.next";
import appConfig from "@/lib/config";
import { buildUrl } from "@/lib/utils";

const generateSitemapLink = (url: string) =>
  `<sitemap><loc>${url}</loc></sitemap>`;

export async function GET() {
  const sitemaps = await generateSitemaps();

  const sitemapIndexXML = `<?xml version="1.0" encoding="UTF-8"?>
    <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
        ${sitemaps
          .map((sitemap) => {
            const url = buildUrl(appConfig.siteDomain, [
              "sitemap",
              `${sitemap.id}.xml`
            ]);
            return generateSitemapLink(url);
          })
          .join("")}
    </sitemapindex>`;

  return new Response(sitemapIndexXML, {
    headers: { "Content-Type": "text/xml" }
  });
}