import { Timer } from '@matrixai/timer';
/**
 * Internal data structure used to track a buckets' information.
 * Internal use only so explicitly not exported.
 */
type TokenBucket = {
    creationTimestamp: number;
    tokens: number;
    lastRefillTimestamp: number;
    capacity: number;
    refillRatePerSecond: number;
};
declare class RateLimiter {
    protected defaultTTL: number;
    protected defaultCapacity: number;
    protected defaultRate: number;
    protected defaultConsume: number;
    protected tokenBuckets: Map<string, TokenBucket>;
    protected expirationTimers: Map<string, Timer>;
    protected refillTimer: Timer | undefined;
    constructor(defaultTTL?: number, defaultCapacity?: number, defaultRate?: number, defaultConsume?: number);
    /**
     * Starts the Refill interval timer
     */
    startRefillInterval(): void;
    /**
     * Stops the Refill interval timer
     */
    stopRefillInterval(): void;
    /**
     * Refills a second worth of tokens defined by the `refillRatePerSecond`.
     */
    refill(): void;
    /**
     * Consumes an amount of tokens for a given bucket. Will return true if the tokens were available to be consumed.
     * Otherwise, returns false if there were insufficient tokens.
     * @param key - Key for the given bucket.
     * @param tokensToConsume - Number of tokens to consume.
     * @returns True if there were sufficient tokens that were consumed. False otherwise with no tokens consumed.
     */
    consume(key: string, tokensToConsume?: number): boolean;
    /**
     * Gets the available tokens for a given bucket.
     * @param key - Key for the given bucket.
     */
    tokens(key: string): number;
    /**
     * Clears all existing `TokenBuckets` .
     */
    clearBuckets(): void;
    /**
     * Stops refreshing and clears all existing `TokenBucket`s
     */
    stop(): void;
    protected scheduleExpiration(key: string, ttl: number): void;
    protected getBucket(key: string, ttl?: number): TokenBucket;
}
export default RateLimiter;