import type { CircuitStateStore, SharedCircuitState } from '../ops/circuit-breaker.js';
import { type PostgresLikeClient } from './client.js';
/** Options for the Postgres circuit store. */
export interface PostgresCircuitStateStoreOptions {
    /** Table name, optionally schema-qualified. Defaults to `nexus_circuits`. */
    table?: string;
    /** Clock for probe leases. Defaults to `Date.now`, the same clock the breaker uses. */
    now?: () => number;
}
/** The schema, as statements. */
export declare function circuitStoreMigration(options?: Pick<PostgresCircuitStateStoreOptions, 'table'>): string[];
/**
 * Shared circuit state in Postgres.
 *
 * Both operations the breaker needs to be atomic are single statements: a transition is written only
 * when it is at least as new as the stored one, and a probe is claimed only when no other worker holds
 * an unexpired claim. One row per provider, so a sync reads a handful of rows.
 */
export declare class PostgresCircuitStateStore implements CircuitStateStore {
    private readonly client;
    private readonly options;
    private readonly table;
    private readonly now;
    constructor(client: PostgresLikeClient, options?: PostgresCircuitStateStoreOptions);
    /** Creates the table if it does not exist. Never runs implicitly. */
    migrate(): Promise<void>;
    /** Every provider's shared circuit state. */
    read(): Promise<SharedCircuitState[]>;
    /**
     * Writes a transition, unless a newer one is already stored. Releases the provider's probe claim.
     */
    write(state: SharedCircuitState): Promise<void>;
    /**
     * Claims the right to probe a provider for `ttlMs`, in one statement. Resolves true for the
     * claimant, including when it already holds the claim.
     */
    claimProbe(providerName: string, owner: string, ttlMs: number): Promise<boolean>;
}