function requestOrigin(request: Request) {
  const proto = request.headers.get("x-forwarded-proto") || new URL(request.url).protocol.replace(":", "");
  const host = request.headers.get("x-forwarded-host") || request.headers.get("host") || new URL(request.url).host;
  return `${proto}://${host}`;
}

/** Browser form POSTs and fetch requests must originate from this Hub. */
export function requireSameOrigin(request: Request) {
  const origin = request.headers.get("origin");
  if (!origin || origin !== requestOrigin(request)) throw new Error("Invalid request origin");
}

export function clientIp(request: Request) {
  return request.headers.get("x-forwarded-for")?.split(",")[0].trim() || request.headers.get("x-real-ip") || "unknown";
}