/**
 * Upstash Redis Storage Adapter
 *
 * Upstash Redis (REST-based) storage implementation for edge deployment.
 * Supports pub/sub via Upstash's REST API with polling mechanism.
 */
import { BaseStorageAdapter } from './base';
import type { UpstashAdapterOptions, SetOptions, MessageHandler, Unsubscribe } from '../types';
/**
 * Upstash Redis storage adapter.
 *
 * Features:
 * - REST-based storage for edge deployment
 * - Native TTL support
 * - Pub/sub support via list-based polling
 *
 * @example
 * ```typescript
 * const adapter = new UpstashStorageAdapter({
 *   url: process.env.UPSTASH_REDIS_REST_URL,
 *   token: process.env.UPSTASH_REDIS_REST_TOKEN,
 *   enablePubSub: true,
 * });
 *
 * await adapter.connect();
 * await adapter.set('key', 'value', { ttlSeconds: 300 });
 * const value = await adapter.get('key');
 *
 * // Pub/sub
 * const unsubscribe = await adapter.subscribe('channel', (msg) => console.log(msg));
 * await adapter.publish('channel', 'hello');
 *
 * await adapter.disconnect();
 * ```
 */
export declare class UpstashStorageAdapter extends BaseStorageAdapter {
    protected readonly backendName = "upstash";
    private client?;
    private readonly options;
    private readonly keyPrefix;
    private readonly pubSubEnabled;
    private readonly subscriptionHandlers;
    private readonly pollingIntervals;
    constructor(options?: UpstashAdapterOptions);
    connect(): Promise<void>;
    disconnect(): Promise<void>;
    ping(): Promise<boolean>;
    /**
     * Get the connected Upstash client, throwing if not connected.
     */
    private getConnectedClient;
    get(key: string): Promise<string | null>;
    protected doSet(key: string, value: string, options?: SetOptions): Promise<void>;
    delete(key: string): Promise<boolean>;
    exists(key: string): Promise<boolean>;
    mget(keys: string[]): Promise<(string | null)[]>;
    mdelete(keys: string[]): Promise<number>;
    expire(key: string, ttlSeconds: number): Promise<boolean>;
    ttl(key: string): Promise<number | null>;
    keys(pattern?: string): Promise<string[]>;
    incr(key: string): Promise<number>;
    decr(key: string): Promise<number>;
    incrBy(key: string, amount: number): Promise<number>;
    supportsPubSub(): boolean;
    publish(channel: string, message: string): Promise<number>;
    subscribe(channel: string, handler: MessageHandler): Promise<Unsubscribe>;
    /**
     * Publish using list-based approach (for polling subscribers).
     * This is an alternative to native PUBLISH when subscribers are polling.
     */
    publishToQueue(channel: string, message: string): Promise<void>;
    protected getPubSubSuggestion(): string;
    /**
     * Add prefix to a key.
     */
    private prefixKey;
    /**
     * Remove prefix from a key.
     */
    private unprefixKey;
}