/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import type { SixthUserInfo } from './sixthAuth.js';
export declare class SixthUserCache {
    /**
     * Check if user is authenticated (has cached user info) - FAST synchronous check first
     */
    static isUserAuthenticated(): Promise<boolean>;
    /**
     * Fast synchronous check if cache file exists
     */
    private static isUserCacheFileExists;
    /**
     * Get cached user info
     */
    static getUserInfo(): Promise<SixthUserInfo | null>;
    /**
     * Cache user info
     */
    static cacheUserInfo(userInfo: SixthUserInfo): Promise<void>;
    /**
     * Clear cached user info
     */
    static clearUserInfo(): Promise<void>;
    /**
     * Get user's subscription status
     */
    static isUserSubscriber(): Promise<boolean>;
    /**
     * Background validation - validate cached token with server (non-blocking)
     */
    static validateInBackground(): void;
}
