export function collapsedSidebarSectionsStorageKey(
  userId: string | null | undefined,
): string | null {
  if (!userId) return null;
  return `rakazo:collapsed-sidebar-sections:${userId}`;
}

export function readCollapsedSidebarSections(userId: string | null | undefined): Set<string> {
  const storageKey = collapsedSidebarSectionsStorageKey(userId);
  if (!storageKey) return new Set();
  try {
    const value = window.localStorage.getItem(storageKey);
    const keys: unknown = value ? JSON.parse(value) : [];
    return new Set(
      Array.isArray(keys) ? keys.filter((key): key is string => typeof key === "string") : [],
    );
  } catch {
    return new Set();
  }
}