import { NextResponse, type NextRequest } from "next/server";

/**
 * Edge-light routing guard: redirects unauthenticated visitors away from /app and /admin
 * based on the presence of the session cookie. Real verification happens server-side in
 * `requireUser()`; this only avoids a flash of protected UI.
 */
export function proxy(req: NextRequest) {
  const { pathname } = req.nextUrl;
  const hasSession = req.cookies.getAll().some((c) => /polyllm.*session_token/.test(c.name));
  if ((pathname.startsWith("/app") || pathname.startsWith("/admin")) && !hasSession) {
    const url = req.nextUrl.clone();
    url.pathname = "/login";
    url.searchParams.set("next", pathname);
    return NextResponse.redirect(url);
  }
  if ((pathname === "/login" || pathname === "/signup") && hasSession) {
    // A stale/revoked session cookie: `requireUser()` sent the visitor here with ?expired=1.
    // Clear the cookies and show the login page instead of bouncing back to /app forever.
    if (req.nextUrl.searchParams.has("expired")) {
      const res = NextResponse.next();
      for (const c of req.cookies.getAll()) if (/polyllm.*session/.test(c.name)) res.cookies.delete(c.name);
      return res;
    }
    const url = req.nextUrl.clone();
    url.pathname = "/app/chat";
    url.search = "";
    return NextResponse.redirect(url);
  }
  return NextResponse.next();
}

export const config = {
  matcher: ["/app/:path*", "/admin/:path*", "/login", "/signup"],
};