const FORBIDDEN_PORT = 8788;

export function parseExternalE2eOrigin(value) {
  if (value === undefined) return undefined;
  if (value === '') throw new Error('E2E_ORIGIN must not be empty when set.');

  let url;
  try {
    url = new URL(value);
  } catch {
    throw new Error('E2E_ORIGIN must be a valid absolute URL.');
  }

  if (
    url.protocol !== 'http:' ||
    url.hostname !== '127.0.0.1' ||
    !url.port ||
    url.username ||
    url.password ||
    url.pathname !== '/' ||
    url.search ||
    url.hash
  ) {
    throw new Error(
      'E2E_ORIGIN must be an HTTP origin on numeric loopback with an explicit port (for example http://127.0.0.1:8789).',
    );
  }

  if (Number(url.port) === FORBIDDEN_PORT) {
    throw new Error(`E2E_ORIGIN must not use forbidden legacy port ${FORBIDDEN_PORT}.`);
  }

  return url.origin;
}