/**
 * A dedicated, self-healing Postgres `LISTEN` connection.
 *
 * Every cross-instance feature in the backend needs the same thing: one
 * connection *outside* the Drizzle pool that stays open, holds a `LISTEN`, and
 * comes back on its own after the database or the network drops it. CDC needed
 * it first; the channel bus needs it too. This is that connection, with the one
 * behaviour that matters to callers preserved: the **first** connect is
 * validated and rethrown, so a caller can fall back to a different strategy,
 * while every later drop is repaired quietly in the background.
 *
 * `LISTEN` is session state, so this connection must not go through a
 * transaction-mode pooler (PgBouncer): give it the direct database URL.
 */
export interface PgNotifyListenerOptions {
    /** Direct Postgres connection string (must bypass a transaction-mode pooler). */
    connectionString: string;
    /** NOTIFY channel to LISTEN on. Must be a plain identifier — it is interpolated. */
    channel: string;
    /** Called for every notification payload received. */
    onPayload: (payload: string) => void | Promise<void>;
    /** Prefix for log lines, e.g. `"[CDC]"`. */
    logLabel: string;
    /** Delay before a reconnect attempt. */
    reconnectDelayMs?: number;
}
export declare class PgNotifyListener {
    private readonly options;
    private client?;
    private running;
    private reconnectTimer?;
    constructor(options: PgNotifyListenerOptions);
    /** Whether the listener is meant to be connected right now. */
    get active(): boolean;
    /**
     * Connect and begin listening. Idempotent.
     *
     * Rejects if the *initial* connection or `LISTEN` fails, leaving the
     * listener stopped — callers use that to degrade deliberately instead of
     * running blind against a channel nothing is delivering.
     */
    start(): Promise<void>;
    /** Stop listening and release the connection. Idempotent. */
    stop(): Promise<void>;
    private connect;
    private scheduleReconnect;
}