import type { Pool } from 'pg';
export type EventRow = {
    event_id: number;
    uuid: string;
    name: string;
    data: unknown;
    status: string;
    created_at: string;
    started_at: string | null;
    completed_at: string | null;
};
/**
 * Wraps all PostgreSQL interactions for the event queue.
 * Accepts a pg Pool so it can be replaced with a mock in tests.
 */
export declare class EventStorage {
    private pool;
    constructor(pool: Pool);
    /**
     * Atomically claims up to `batchSize` pending events using a single CTE
     * query — no BEGIN/COMMIT/ROLLBACK needed, eliminating the pg multi-query
     * deprecation warning entirely.
     */
    claimBatch(batchSize: number): Promise<EventRow[]>;
    /**
     * Marks an event as successfully completed and removes it from the table.
     * Updates status first so a failed DELETE doesn't leave the event as pending.
     */
    markDoneAndDelete(uuid: string): Promise<void>;
    /**
     * At startup: mark any events that were stuck as 'processing' during a
     * prior crash as 'failed'. At-most-once delivery — subscribers are never
     * called twice. Returns the number of events marked failed.
     */
    markStuckAsFailed(): Promise<number>;
}