import { GatewayError, type GatewayModelTarget } from "./types.js";
export type GatewayCircuitState = "closed" | "open" | "half-open";
export interface GatewayCircuitSnapshot {
    state: GatewayCircuitState;
    failures: number;
    inFlight: number;
    openUntil?: number;
}
export interface GatewayCircuitPermit {
    end(outcome: "success" | "retryable-error" | "neutral", retryAfterMs?: number): void;
}
export interface GatewayCircuitBreaker {
    acquire(target: GatewayModelTarget): GatewayCircuitPermit | undefined;
    snapshot(target: GatewayModelTarget): GatewayCircuitSnapshot | undefined;
    canAttempt(target: GatewayModelTarget): boolean;
}
export interface GatewayCircuitOptions {
    failureThreshold?: number;
    cooldownMs?: number;
    maxCooldownMs?: number;
    halfOpenMaxProbes?: number;
    maxTargets?: number;
    now?: () => number;
    onStateChange?: (event: {
        target: GatewayModelTarget;
        from: GatewayCircuitState;
        to: GatewayCircuitState;
        at: number;
        openUntil?: number;
    }) => void | Promise<void>;
}
export declare class GatewayCircuitOpenError extends GatewayError {
    constructor();
}
export declare const createGatewayCircuitBreaker: (options?: GatewayCircuitOptions) => GatewayCircuitBreaker;
//# sourceMappingURL=circuit-breaker.d.ts.map