// app/api/sitemap/route.ts
import { NextResponse } from "next/server";

export async function GET(req: Request) {
  try {
    const { searchParams } = new URL(req.url);
    const u = searchParams.get("u");
    if (!u) return NextResponse.json({ error: "Missing ?u=" }, { status: 400 });

    const target = new URL(u.match(/^https?:\/\//i) ? u : `https://${u}`);

    // This is correct: no double-escaping
    const candidates: string[] = /\/sitemap(.*)\.xml$/i.test(target.pathname)
      ? [target.toString()]
      : [
          new URL("/sitemap.xml", target.origin).toString(),
          new URL("/sitemap_index.xml", target.origin).toString(),
        ];

    // fetch & parse each candidate; you can also call your backend util if exposed
    const urls = new Set<string>();

    // very light probe: just check existence; swap to real parser if needed
    for (const href of candidates) {
      try {
        const r = await fetch(href, { headers: { "user-agent": "CrawlerX/1.0" }, cache: "no-store" });
        if (r.ok) urls.add(href);
      } catch {}
    }

    // If you want full expansion, call your backend endpoint instead of the above loop

    return NextResponse.json({ ok: true, origin: target.origin, count: urls.size, urls: [...urls] });
  } catch (e: any) {
    return NextResponse.json({ error: e?.message || "Bad URL" }, { status: 400 });
  }
}