/**
 * Redis Streams distributed job queue.
 *
 * Provides horizontal crawler scaling via Redis Streams consumer groups.
 * Multiple crawler nodes can pull from the same stream — each job is
 * delivered to exactly one consumer (at-least-once via ACK/PENDING).
 *
 * Used when REDIS_URL is set AND JOB_QUEUE_BACKEND=redis.
 * Falls back to the Postgres-backed queue when Redis is unavailable.
 *
 * Stream key:   zeta:crawl:stream
 * Group name:   zeta:crawl:workers
 * Consumer id:  zeta:worker:<hostname>:<pid>
 */
export interface RedisQueueJob {
    id: string;
    jobId: string;
    tenantId: string;
    projectId: string;
    payload: Record<string, unknown>;
    enqueuedAt: string;
}
export interface RedisQueueClient {
    enqueue(jobId: string, tenantId: string, projectId: string, payload?: Record<string, unknown>): Promise<string>;
    dequeue(timeoutMs?: number): Promise<RedisQueueJob | null>;
    ack(streamEntryId: string): Promise<void>;
    nack(streamEntryId: string): Promise<void>;
    reclaimStale(maxIdleMs?: number): Promise<RedisQueueJob[]>;
    stats(): Promise<{
        pending: number;
        delivered: number;
        groupLag: number;
    }>;
    close(): Promise<void>;
}
/**
 * Create a Redis Streams job queue client.
 * Throws if REDIS_URL is not set.
 */
export declare function createRedisQueue(): Promise<RedisQueueClient>;
/**
 * Check if Redis queue backend is configured.
 */
export declare function isRedisQueueEnabled(): boolean;
/**
 * Convenience: create queue only if enabled, else return null.
 */
export declare function maybeCreateRedisQueue(): Promise<RedisQueueClient | null>;