scrabble-game/ui/src/lib/offline.ts

// Pure helpers for offline-mode support, kept out of the reactive module (offline.svelte.ts) so they
// unit-test in the node env. Offline became implicit — the net-state machine detects connectivity, and
// there is no deliberate toggle — so only the background dict-preload eligibility check and a one-time
// cleanup of the retired deliberate-offline preference remain here.

const STORAGE_KEY = 'scrabble.offlineMode';

/**
 * clearOfflinePref removes the retired deliberate-offline preference key. The offline model is implicit
 * now — the app boots online and the machine detects offline — so a persisted flag from a pre-redesign
 * install is orphaned data that is never read again; boot clears it once (best-effort) so nobody is left
 * with a dead key.
 */
export function clearOfflinePref(): void {
  try {
    if (typeof localStorage !== 'undefined') localStorage.removeItem(STORAGE_KEY);
  } catch {
    /* best-effort — a storage failure just leaves the orphaned key, which is never read anyway */
  }
}

/**
 * offlinePreloadEligible reports whether a background dictionary preload should run in this context: an
 * installed standalone web PWA (not a Telegram/VK mini-app, not a plain browser tab) with a confirmed
 * email, currently online. Elsewhere the preload is wasted bandwidth — the context has no offline play
 * to prepare for — so kickDictPreload skips it.
 */
export function offlinePreloadEligible(opts: {
  hasEmail: boolean;
  standalone: boolean;
  inTelegram: boolean;
  inVK: boolean;
  online: boolean;
}): boolean {
  return opts.hasEmail && opts.standalone && !opts.inTelegram && !opts.inVK && opts.online;
}