import { NextResponse } from 'next/server';
import { countAssets } from '@/lib/queries/assets';

export const dynamic = 'force-dynamic';

const SITE = process.env.NEXT_PUBLIC_SITE_URL ?? 'https://www.rareindex.io';
const PAGE = 20_000;

/** Sitemap index: /sitemap/0.xml (static + categories + indices + sets) then paginated asset sitemaps. */
export async function GET() {
  let n = 0;
  try {
    n = await countAssets();
  } catch {
    n = 0;
  }
  const pages = 1 + Math.max(1, Math.ceil(n / PAGE));
  const now = new Date().toISOString();
  const body = `<?xml version="1.0" encoding="UTF-8"?>\n<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">\n${Array.from({ length: pages }, (_, i) => `  <sitemap><loc>${SITE}/sitemap/${i}.xml</loc><lastmod>${now}</lastmod></sitemap>`).join('\n')}\n</sitemapindex>\n`;
  return new NextResponse(body, { headers: { 'content-type': 'application/xml; charset=utf-8', 'cache-control': 'public, max-age=3600' } });
}