/**
 * Query parameters that only exist to record where a link travelled. They
 * are dropped so the copy button hands back something clean and the cache
 * does not store one post under a dozen keys.
 */
const TRACKING_PARAMS = new Set([
  'igsh', 'igshid', 'img_index', 'fbclid', 'gclid', 'mibextid',
  'ref_src', 'ref_url', 'ref', 'source', 'checksum', 'social_sharing',
  's', 't', 'si', 'xmt', '_r', '_t', '_d',
  'is_from_webapp', 'sender_device', 'sender_web_id', 'web_id',
  'share_app_id', 'share_link_id', 'share_item_id', 'tt_from',
]);

export function stripTracking(url: URL): URL {
  const cleaned = new URL(url.href);
  for (const key of [...cleaned.searchParams.keys()]) {
    if (TRACKING_PARAMS.has(key) || key.startsWith('utm_')) {
      cleaned.searchParams.delete(key);
    }
  }
  cleaned.hash = '';
  return cleaned;
}

/** Exact-host or subdomain match, e.g. `tiktok.com` and `vm.tiktok.com`. */
export function hostMatcher(...domains: string[]): (host: string) => boolean {
  return (host) => domains.some((d) => host === d || host.endsWith(`.${d}`));
}