import { evictAll } from '@/lib/account-state-manager';

// localStorage keys holding server-derived, re-fetchable caches. The "Refresh
// cached data" action clears these so a stale or wrong-account view can be
// fixed WITHOUT signing out (which would drop the whole account list).
//
// Deliberately excluded:
//  - 'account-registry' / 'auth-storage'  → keep accounts + sessions
//  - 'settings-storage' / 'theme-storage' / 'locale-storage' → user prefs
//  - 'template-storage' / 'smime-preferences' → user-created content
const CACHE_STORAGE_KEYS = [
  'email-snapshot',
  'identity-storage',
  'contact-storage',
  'calendar-storage',
  'calendar-notification-storage',
];

/**
 * The user's iCal subscriptions exist only in the calendar store's persisted
 * state, next to its caches: keep them and drop the rest.
 */
function clearCalendarStorage(storage: Storage): void {
  let persisted: { state?: { icalSubscriptions?: unknown }; version?: unknown } | null = null;
  try {
    persisted = JSON.parse(storage.getItem('calendar-storage') ?? 'null');
  } catch {
    /* not ours to read: drop it */
  }
  const subscriptions = persisted?.state?.icalSubscriptions;
  if (!Array.isArray(subscriptions) || subscriptions.length === 0) {
    storage.removeItem('calendar-storage');
    return;
  }
  storage.setItem('calendar-storage', JSON.stringify({
    state: { icalSubscriptions: subscriptions },
    version: persisted?.version ?? 0,
  }));
}

/**
 * Clear cached, server-derived data (contacts, calendars, identities, and the
 * in-memory per-account snapshots), then reload so everything is re-fetched
 * fresh for the active account. Accounts, sessions and iCal subscriptions are
 * preserved — this is the non-destructive alternative to the browser's
 * "clear site data", which also wipes the account list.
 */
export function clearCachedData(): void {
  // Drop the in-memory per-account store snapshots so a reload can't restore
  // stale cached state for any account.
  try {
    evictAll();
  } catch {
    /* snapshots are best-effort */
  }

  if (typeof window === 'undefined') return;

  for (const key of CACHE_STORAGE_KEYS) {
    try {
      if (key === 'calendar-storage') clearCalendarStorage(window.localStorage);
      else window.localStorage.removeItem(key);
    } catch {
      /* ignore storage access errors */
    }
  }

  window.location.reload();
}