const PREFIX = "ihasmail:";

export function loadJson<T>(key: string, fallback: T): T {
  try {
    const raw = localStorage.getItem(PREFIX + key);
    if (raw == null) return fallback;
    return { ...fallback, ...(JSON.parse(raw) as T) };
  } catch {
    return fallback;
  }
}

export function loadRaw<T>(key: string, fallback: T): T {
  try {
    const raw = localStorage.getItem(PREFIX + key);
    if (raw == null) return fallback;
    return JSON.parse(raw) as T;
  } catch {
    return fallback;
  }
}

export function saveJson(key: string, value: unknown): void {
  try {
    localStorage.setItem(PREFIX + key, JSON.stringify(value));
  } catch {
    /* quota exceeded or private mode */
  }
}

export function removeKey(key: string): void {
  try {
    localStorage.removeItem(PREFIX + key);
  } catch {
    /* ignore */
  }
}

/** Namespaced per account so multiple logins on one browser don't collide. */
export function accountKey(accountId: string | null | undefined, key: string): string {
  return `${accountId ?? "anon"}:${key}`;
}