/**
 * @module CircuitBreaker
 */
import { type BackoffPolicy } from "../../../../backoff-policies/contracts/_module.js";
import { CIRCUIT_BREAKER_STATE, type ICircuitBreakerPolicy } from "../../../../circuit-breaker/contracts/_module.js";
/**
 * @internal
 */
export type BackoffPolicySettings = {
    currentDate: Date;
    backoffPolicy: BackoffPolicy;
};
/**
 * @internal
 */
export type OpenedState = {
    type: typeof CIRCUIT_BREAKER_STATE.OPEN;
    attempt: number;
    /**
     * Unix timestamp in miliseconds
     */
    startedAt: number;
};
/**
 * @internal
 */
export type HalfOpenedState<TMetrics = unknown> = {
    type: typeof CIRCUIT_BREAKER_STATE.HALF_OPEN;
    attempt: number;
    metrics: TMetrics;
};
/**
 * @internal
 */
export type ClosedState<TMetrics = unknown> = {
    type: typeof CIRCUIT_BREAKER_STATE.CLOSED;
    metrics: TMetrics;
};
/**
 * @internal
 */
export type IsolatedState = {
    type: typeof CIRCUIT_BREAKER_STATE.ISOLATED;
};
/**
 * @internal
 */
export type AllCircuitBreakerState<TMetrics = unknown> = ClosedState<TMetrics> | OpenedState | HalfOpenedState<TMetrics> | IsolatedState;
/**
 * @internal
 */
export declare class InternalCircuitBreakerPolicy<TMetrics = unknown> {
    private readonly circuitBreakerPolicy;
    constructor(circuitBreakerPolicy: ICircuitBreakerPolicy<TMetrics>);
    private isMetricsEqual;
    private isClosedStateEqual;
    private isOpenedStateEqual;
    private isHalfOpenedStateEqual;
    private isIsolatedStateEqual;
    isEqual(stateA: AllCircuitBreakerState<TMetrics>, stateB: AllCircuitBreakerState<TMetrics>): boolean;
    initialState(): ClosedState<TMetrics>;
    whenClosed(currentState: ClosedState<TMetrics>, currentDate: Date): ClosedState<TMetrics> | OpenedState;
    whenOpened(currentState: OpenedState, settings: BackoffPolicySettings): OpenedState | HalfOpenedState<TMetrics>;
    whenHalfOpened(currentState: HalfOpenedState<TMetrics>, currentDate: Date): ClosedState<TMetrics> | OpenedState | HalfOpenedState<TMetrics>;
    trackSuccessWhenClosed(currentState: ClosedState<TMetrics>, currentDate: Date): ClosedState<TMetrics>;
    trackFailureWhenClosed(currentState: ClosedState<TMetrics>, currentDate: Date): ClosedState<TMetrics>;
    trackSuccessWhenHalfOpened(currentState: HalfOpenedState<TMetrics>, currentDate: Date): HalfOpenedState<TMetrics>;
    trackFailureWhenHalfOpened(currentState: HalfOpenedState<TMetrics>, currentDate: Date): HalfOpenedState<TMetrics>;
}