export default class LeakyBucket {
    private queue;
    private totalCost;
    private currentCapacity;
    private lastRefill;
    private refillRate;
    private timer;
    private emptyPromiseResolver;
    private emptyPromise;
    private capacity;
    private maxCapacity;
    private timeout;
    private interval;
    /**
     * Sets up the leaky bucket. The bucket is designed so that it can
     * burst by the capacity it is given. after that items can be queued
     * until a timeout of n seonds is reached.
     *
     * example: throttle 10 actions per minute that have each a cost of 1, reject
     * everything theat is overflowing. there will no more than 10 items queued
     * at any time
     *   capacity: 10
     *   interval: 60
     *   timeout: 60
     *
     * example: throttle 100 actions per minute that have a cost of 1, reject
     * items that have to wait more thatn 2 minutes. there will be no more than
     * 200 items queued at any time. of those 200 items 100 will be bursted within
     * a minute, the rest will be executed evenly spread over a mintue.
     *   capacity: 100
     *   interval: 60
     *   timeout: 120
     *
     * @param {number} capacity the capacity the bucket has per interval
     * @param {number} timeout the total time items are allowed to wait for execution
     * @param {number} interval the interval for the capacity in seconds
     */
    constructor({ capacity, timeout, interval, }?: {
        capacity?: number;
        timeout?: number;
        interval?: number;
    });
    get length(): number;
    /**
     * the throttle method is used to throttle things. it is async and will resolve either
     * immediatelly, if there is space in the bucket, than can be bursted, or it will wait
     * until there is enough capacity left to execute the item with the given cost. if the
     * bucket is overflowing, and the item cannot be executed within the timeout of the bucket,
     * the call will be rejected with an error.
     *
     * @param {number} cost=1 the cost of the item to be throttled. is the cost is unknown,
     *                        the cost can be payed after execution using the pay method.
     *                        defaults to 1.
     * @param {boolean} append = true set to false if the item needs ot be added to the
     *                                beginning of the queue
     * @param {boolean} isPause = false defines if the element is a pause elemtn, if yes, it
     *                                  will not be cleaned off of the queue when checking
     *                                  for overflowing elements
     * @returns {promise} resolves when the item can be executed, rejects if the item cannot
     *                    be executed in time
     */
    throttle(cost?: number, append?: boolean, isPause?: boolean): Promise<unknown>;
    /**
     * either executes directly when enough capacity is present or delays the
     * execution until enough capacity is available.
     *
     * @private
     */
    startTimer(): void;
    /**
     * removes the first item in the queue, resolves the promise that indicated
     * that the bucket is empty and no more items are waiting
     *
     * @private
     */
    shiftQueue(): void;
    /**
     * is resolved as soon as the bucket is empty. is basically an event
     * that is emitted
     */
    isEmpty(): Promise<any>;
    /**
     * ends the bucket. The bucket may be recycled after this call
     */
    end(): void;
    /**
     * removes all items from the queue, does not stop the timer though
     *
     * @privae
     */
    clear(): void;
    /**
     * can be used to pay costs for items where the cost is clear after exection
     * this will devcrease the current capacity availabe on the bucket.
     *
     * @param {number} cost the ost to pay
     */
    pay(cost: any): void;
    /**
     * stops the running times
     *
     * @private
     */
    stopTimer(): void;
    /**
     * refills the bucket with capacity which has become available since the
     * last refill. starts to refill after a call has started using capacity
     *
     * @private
     */
    refill(): void;
    /**
     * gets the currenlty avilable max capacity, respecintg
     * the capacity that is already used in the moment
     *
     * @private
     */
    getCurrentMaxCapacity(): number;
    /**
     * removes all items that cannot be executed in time due to items
     * that were added in front of them in the queue (mostly pause items)
     *
     * @private
     */
    cleanQueue(): void;
    /**
     * returns the first item from the queue
     *
     * @private
     */
    getFirstItem(): any;
    /**
     * pasue the bucket for the given cost. means that an item is added in the
     * front of the queue with the cost passed to this method
     *
     * @param {number} cost the cost to pasue by
     */
    pauseByCost(cost: any): void;
    /**
     * pause the bucket for n seconds. means that an item with the cost for one
     * second is added at the beginning of the queue
     *
     * @param {number} seconds the number of seconds to pause the bucket by
     */
    pause(seconds?: number): void;
    /**
     * drains the bucket, so that nothing can be exuted at the moment
     *
     * @private
     */
    drain(): void;
    /**
     * set the timeout value for the bucket. this is the amount of time no item
     * may longer wait for.
     *
     * @param {number} timeout in seonds
     */
    setTimeout(timeout: any): this;
    /**
     * set the interval within whch the capacity can be used
     *
     * @param {number} interval in seonds
     */
    setInterval(interval: any): this;
    /**
     * set the capacity of the bucket. this si the capacity that can be used per interval
     *
     * @param {number} capacity
     */
    setCapacity(capacity: any): this;
    /**
     * claculates the values of some frequently used variables on the bucket
     *
     * @private
     */
    updateVariables(): void;
}