import type { AuthState } from "@0xmonaco/types";
/**
 * Save auth state to localStorage
 *
 * @security This function stores the session keypair (including the private
 * key) in localStorage, which is accessible to any JavaScript running on the
 * page. This is the same XSS exposure as the previous JWT-based scheme — an
 * attacker who can read localStorage can act as the user until the session
 * expires either way.
 *
 * Security recommendations:
 * - Implement Content Security Policy (CSP) headers to mitigate XSS risks
 * - Sanitize all user input to prevent XSS vulnerabilities
 * - Consider the tradeoffs: localStorage provides persistence across sessions but sacrifices XSS protection
 * - For higher-security requirements, back the session key with a
 *   non-extractable WebCrypto key (out of scope for this default helper)
 *
 * @param authState - The authentication state to persist
 */
export declare function saveAuthState(authState: AuthState): void;
/**
 * Load auth state from localStorage
 * @returns The persisted auth state or null if not found/invalid
 */
export declare function loadAuthState(): AuthState | null;
/**
 * Clear auth state from localStorage
 */
export declare function clearAuthState(): void;
/**
 * Check if the stored token is expired
 * @param authState - The auth state to check
 * @param bufferSeconds - Buffer time before actual expiry (default: 60 seconds)
 * @returns True if token is expired or will expire within buffer time
 */
export declare function isTokenExpired(authState: AuthState, bufferSeconds?: number): boolean;
/**
 * Get time until token expiration in seconds
 * @param authState - The auth state to check
 * @returns Seconds until expiration (negative if already expired)
 */
export declare function getTimeUntilExpiry(authState: AuthState): number;