/**
 * Which slugs a category may take. Category slugs live at the URL root (e.g.
 * /music), so they must never collide with the frontend's own routes.
 *
 * @module
 */

/**
 * Top-level path segments that already have meaning in the SPA router (see
 * src/App.tsx), plus a few reserved for infrastructure.
 */
export const RESERVED_SLUGS: readonly string[] = [
  "~",
  "dumps",
  "users",
  "playlists",
  "search",
  "login",
  "register",
  "notifications",
  "reset-password",
  "manage",
  "api",
  "assets",
];

/**
 * A well-formed category slug: lowercase alphanumerics,
 * hyphen-separated, no leading, trailing or double hyphen.
 */
export const CATEGORY_SLUG_RE = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;

/** Checks whether `slug` is well-formed (see {@link CATEGORY_SLUG_RE}). */
export function isValidSlugFormat(slug: string): boolean {
  return CATEGORY_SLUG_RE.test(slug);
}

/** Checks whether `slug` is one of the {@link RESERVED_SLUGS}. */
export function isReservedSlug(slug: string): boolean {
  return RESERVED_SLUGS.includes(slug);
}

/** Checks whether `slug` is well-formed and not reserved. */
export function isSlugAvailable(slug: string): boolean {
  return isValidSlugFormat(slug) && !isReservedSlug(slug);
}