/**
 * @module RateLimiter
 */
import { type BackoffPolicy } from "../../../../backoff-policies/contracts/_module.js";
import { RATE_LIMITER_STATE, type IRateLimiterPolicy } from "../../../../rate-limiter/contracts/_module.js";
/**
 * @internal
 */
export type AllowedState<TMetrics = unknown> = {
    type: (typeof RATE_LIMITER_STATE)["ALLOWED"];
    metrics: TMetrics;
};
/**
 * @internal
 */
export type BlockedState = {
    type: (typeof RATE_LIMITER_STATE)["BLOCKED"];
    /**
     * Unix timestamp in miliseconds
     */
    startedAt: number;
    attempt: number;
};
/**
 * @internal
 */
export type AllRateLimiterState<TMetrics = unknown> = AllowedState<TMetrics> | BlockedState;
/**
 * @internal
 */
export type BackoffPolicySettings = {
    currentDate: Date;
    backoffPolicy: BackoffPolicy;
};
/**
 * @internal
 */
export declare class InternalRateLimiterPolicy<TMetrics = unknown> {
    private readonly rateLimiterPolicy;
    constructor(rateLimiterPolicy: IRateLimiterPolicy<TMetrics>);
    initialState(currentDate: Date): AllowedState<TMetrics>;
    whenAllowed(currentState: AllowedState<TMetrics>, limit: number, currentDate: Date): AllRateLimiterState<TMetrics>;
    whenBlocked(currentState: BlockedState, settings: BackoffPolicySettings): AllRateLimiterState<TMetrics>;
    trackWhenAllowed(currentState: AllowedState<TMetrics>, currentDate: Date): AllowedState<TMetrics>;
    trackWhenBlocked(currentState: BlockedState): BlockedState;
    getExpiration(currentState: AllRateLimiterState<TMetrics>, settings: BackoffPolicySettings): Date;
    getAttempts(currentState: AllRateLimiterState<TMetrics>, currentDate: Date): number;
}