/**
 * @file Unified Storage Utilities
 * @description Standardized storage abstractions for localStorage, sessionStorage,
 * and in-memory storage with TTL and type safety.
 *
 * @module shared/storage-utils
 */
/**
 * Storage item wrapper with metadata.
 */
export interface StorageItem<T> {
    value: T;
    timestamp: number;
    ttl?: number;
    version?: number;
}
/**
 * Storage options for set operations.
 */
export interface StorageSetOptions {
    /** Time-to-live in milliseconds (0 = no expiration) */
    ttlMs?: number;
    /** Version number for migrations */
    version?: number;
}
/**
 * Storage configuration.
 */
export interface StorageConfig {
    /** Prefix for all keys */
    prefix?: string;
    /** Default TTL in milliseconds */
    defaultTtlMs?: number;
    /** Storage version */
    version?: number;
}
/**
 * Type-safe storage wrapper with TTL support.
 *
 * @example
 * ```ts
 * const storage = new StorageWrapper(localStorage, { prefix: 'app' });
 *
 * // Set with TTL
 * storage.set('user', { name: 'John' }, { ttlMs: 3600000 });
 *
 * // Get with type
 * const user = storage.get<User>('user');
 * ```
 */
export declare class StorageWrapper {
    private storage;
    private config;
    constructor(storage: Storage, config?: StorageConfig);
    /**
     * Set a value in storage.
     */
    set<T>(key: string, value: T, options?: StorageSetOptions): boolean;
    /**
     * Get a value from storage.
     */
    get<T>(key: string, defaultValue?: T): T | undefined;
    /**
     * Remove a value from storage.
     */
    remove(key: string): void;
    /**
     * Check if a key exists and is not expired.
     */
    has(key: string): boolean;
    /**
     * Get all keys with the configured prefix.
     */
    keys(): string[];
    /**
     * Clear all items with the configured prefix.
     */
    clear(): void;
    /**
     * Remove all expired items.
     */
    cleanup(): number;
    /**
     * Get storage statistics.
     */
    getStats(): {
        itemCount: number;
        totalSize: number;
        expiredCount: number;
    };
    /**
     * Get prefixed storage key.
     */
    private getKey;
    /**
     * Check if item is a StorageItem wrapper.
     */
    private isStorageItem;
}
/**
 * In-memory storage implementation (SSR-safe fallback).
 */
export declare class MemoryStorage implements Storage {
    private store;
    get length(): number;
    key(index: number): string | null;
    getItem(key: string): string | null;
    setItem(key: string, value: string): void;
    removeItem(key: string): void;
    clear(): void;
}
/**
 * Check if localStorage is available.
 */
export declare function isLocalStorageAvailable(): boolean;
/**
 * Check if sessionStorage is available.
 */
export declare function isSessionStorageAvailable(): boolean;
/**
 * Get localStorage with fallback to memory storage.
 */
export declare function getLocalStorage(): Storage;
/**
 * Get sessionStorage with fallback to memory storage.
 */
export declare function getSessionStorage(): Storage;
/**
 * Create a localStorage wrapper with prefix.
 */
export declare function createLocalStorage(config?: StorageConfig): StorageWrapper;
/**
 * Create a sessionStorage wrapper with prefix.
 */
export declare function createSessionStorage(config?: StorageConfig): StorageWrapper;
/**
 * Create a memory storage wrapper.
 */
export declare function createMemoryStorage(): StorageWrapper;
/**
 * Set a value in localStorage.
 */
export declare function setLocal<T>(key: string, value: T, options?: StorageSetOptions): boolean;
/**
 * Get a value from localStorage.
 */
export declare function getLocal<T>(key: string, defaultValue?: T): T | undefined;
/**
 * Remove a value from localStorage.
 */
export declare function removeLocal(key: string): void;
/**
 * Set a value in sessionStorage.
 */
export declare function setSession<T>(key: string, value: T, options?: StorageSetOptions): boolean;
/**
 * Get a value from sessionStorage.
 */
export declare function getSession<T>(key: string, defaultValue?: T): T | undefined;
/**
 * Remove a value from sessionStorage.
 */
export declare function removeSession(key: string): void;
/**
 * Safely parse JSON from storage with type guard.
 */
export declare function getJsonFromStorage<T>(storage: Storage, key: string, guard: (value: unknown) => value is T): T | null;
/**
 * Save JSON to storage.
 */
export declare function setJsonToStorage<T>(storage: Storage, key: string, value: T): boolean;
/**
 * Listen for storage changes across tabs.
 *
 * @param callback - Callback when storage changes
 * @param options - Filter options
 * @returns Unsubscribe function
 */
export declare function onStorageChange(callback: (event: StorageEvent) => void, options?: {
    key?: string;
    storage?: Storage;
}): () => void;
/**
 * Watch a specific key for changes.
 */
export declare function watchStorageKey<T>(key: string, callback: (newValue: T | null, oldValue: T | null) => void, options?: {
    storage?: Storage;
}): () => void;