/**
 * QueueProcessor
 *
 * Processes queued file operations with concurrency control and retry logic.
 *
 * Features:
 * - Concurrent worker management (configurable concurrency)
 * - Automatic retry with exponential backoff
 * - Event emission for operation lifecycle
 * - Graceful start/stop
 * - Error handling and logging
 *
 * @module @plyaz/storage/queue
 */
import type { StorageQueueProcessFunction, StorageQueueProcessorConfig } from '@plyaz/types/storage';
import type { EventManager } from '../core/EventManager';
import type { InMemoryQueue } from './InMemoryQueue';
/**
 * Queue processor for concurrent job processing
 *
 * @example
 * ```typescript
 * const queue = new InMemoryQueue({ logger });
 * const processor = new QueueProcessor(
 *   queue,
 *   async (operation) => {
 *     // Process the operation
 *     await storageService.uploadFile(operation.uploadParams);
 *   },
 *   {
 *     concurrency: 5,
 *     maxRetries: 3,
 *     eventManager,
 *     logger,
 *   }
 * );
 *
 * processor.start();
 *
 * // Later...
 * await processor.stop();
 * ```
 */
export declare class QueueProcessor {
    private running;
    private workers;
    private intervalHandle?;
    private readonly queue;
    private readonly processFunction;
    private readonly eventManager?;
    private readonly logger?;
    private readonly config;
    constructor(queue: InMemoryQueue, processFunction: StorageQueueProcessFunction, config?: StorageQueueProcessorConfig<EventManager>);
    /**
     * Start the queue processor
     * Begins polling the queue and processing operations
     */
    start(): void;
    /**
     * Stop the queue processor
     * Waits for all active workers to complete
     */
    stop(): Promise<void>;
    /**
     * Check if processor is running
     */
    isRunning(): boolean;
    /**
     * Get number of active workers
     */
    getActiveWorkerCount(): number;
    /**
     * Tick function - spawns workers up to concurrency limit
     */
    private tick;
    /**
     * Process next operation from queue
     */
    private processNext;
    /**
     * Handle processing error with retry logic
     */
    private handleProcessingError;
    /**
     * Get processor statistics
     */
    getStatistics(): {
        running: boolean;
        activeWorkers: number;
        queueStatistics: ReturnType<InMemoryQueue['getStatistics']>;
    };
}