/**
 * Sign-in URL that returns the shopper to `fullPath` afterwards. `login.vue`
 * only honours a same-origin absolute path, and a redirect back to the sign-in
 * page itself would loop, so that case drops the parameter.
 */
export function signInPath(fullPath: string): string {
  if (!fullPath.startsWith("/") || fullPath.startsWith("//") || fullPath.startsWith("/login")) {
    return "/login";
  }
  return `/login?redirect=${encodeURIComponent(fullPath)}`;
}