import NQSRequest from '../nqs/NQSRequest';
import { Service } from '../nqs/Services';
/**
 * Centralized queue for sending NQSRequest items with retry handling.
 * Features:
 *  - Retry requests are processed before fresh ones
 *  - Failed retry stops further retries in that cycle; remaining retry requests are deferred
 *  - Only retry specific services
 *  - Retry queue is capped and sorted by timemark
 *  - Automatic retry scheduling with exponential backoff (decoupled from pings)
 *  - Max 25 retry attempts before flushing queue
 *
 * Enhancement:
 *  - If a new request is enqueued while processing, schedule one extra processing pass
 *    after the current cycle finishes so that newly enqueued fresh items are not stuck.
 */
export default class RequestQueue {
    private freshRequests;
    private retryRequests;
    private activeRequests;
    private isProcessing;
    private destroyed;
    private pendingAfterProcessing;
    private retryInterval;
    private retryAttemptCount;
    private readonly baseRetryDelay;
    private readonly maxRetryAttempts;
    private readonly fixedRetryAttempts;
    private readonly retryServices;
    private readonly maxRetryRequests;
    private readonly onSuccess;
    private readonly onFail;
    constructor(params: {
        retryServices: Service[];
        maxRetryRequests: number;
        onSuccess: (request: NQSRequest) => void;
        onFail: (request: NQSRequest) => void;
    });
    enqueue(request: NQSRequest): void;
    destroy(): void;
    private process;
    private isRetryable;
    /**
     * Schedules automatic retry processing for failed requests.
     * Uses exponential backoff after 10 attempts and stops after 25 attempts.
     * Decoupled from pings - works even after /stop event.
     * @private
     */
    private _scheduleRetryProcessing;
    /**
     * Calculates the delay for the next retry attempt.
     * First 10 attempts: fixed 5s delay
     * Attempts 11-25: exponential backoff with 2min cap
     * @private
     */
    private _calculateRetryDelay;
    /**
     * Clears the active retry interval and resets attempt counter.
     * Called when queue is empty or service is destroyed.
     * @private
     */
    private _clearRetryInterval;
    /**
     * Flushes the retry queue when max attempts reached.
     * Calls fail callbacks for all pending requests and clears the queue.
     * @private
     */
    private _flushRetryQueue;
}