/**
 * InMemoryQueue
 *
 * In-memory queue for file operations with priority-based processing.
 *
 * Features:
 * - Priority-based queue (high, normal, low)
 * - FIFO ordering within same priority
 * - Statistics tracking (queued, processed, failed)
 * - Processing state management
 *
 * @module @plyaz/storage/queue
 */
import type { StorageQueuedOperation, StorageQueueStatistics, STORAGE_QUEUE_PRIORITY } from '@plyaz/types/storage';
import type { LoggerInterface } from '@plyaz/types';
/**
 * In-memory queue for file operations
 *
 * @example
 * ```typescript
 * const queue = new InMemoryQueue({ logger });
 *
 * await queue.enqueue({
 *   id: '123',
 *   type: 'upload',
 *   uploadParams: { ... },
 *   priority: 'high',
 *   retryCount: 0,
 *   maxRetries: 3,
 *   createdAt: new Date(),
 * });
 *
 * const operation = await queue.dequeue();
 * ```
 */
export declare class InMemoryQueue {
    private queue;
    private processing;
    private totalQueued;
    private processedCount;
    private failedCount;
    private readonly logger?;
    constructor(config?: {
        logger?: LoggerInterface;
    });
    /**
     * Add operation to queue
     * High priority operations are inserted at the front
     * Normal and low priority are added to the back
     */
    enqueue(operation: StorageQueuedOperation): Promise<void>;
    /**
     * Remove and return next operation from queue
     * Returns null if queue is empty
     */
    dequeue(): Promise<StorageQueuedOperation | null>;
    /**
     * Get current queue size
     */
    size(): number;
    /**
     * Check if queue is empty
     */
    isEmpty(): boolean;
    /**
     * Set processing state
     */
    setProcessing(processing: boolean): void;
    /**
     * Check if queue is currently being processed
     */
    isProcessing(): boolean;
    /**
     * Increment processed count
     */
    incrementProcessed(): void;
    /**
     * Increment failed count
     */
    incrementFailed(): void;
    /**
     * Get queue statistics
     */
    getStatistics(): StorageQueueStatistics;
    /**
     * Clear all operations from queue
     * Useful for testing or emergency shutdown
     */
    clear(): void;
    /**
     * Get all operations in queue (for debugging/monitoring)
     * Returns a copy to prevent external modification
     */
    getAll(): StorageQueuedOperation[];
    /**
     * Peek at next operation without removing it
     */
    peek(): StorageQueuedOperation | null;
    /**
     * Remove specific operation by ID
     * Returns true if operation was found and removed
     */
    remove(operationId: string): boolean;
    /**
     * Find operation by ID
     */
    find(operationId: string): StorageQueuedOperation | undefined;
    /**
     * Get operations by type
     */
    getByType(type: StorageQueuedOperation['type']): StorageQueuedOperation[];
    /**
     * Get operations by priority
     */
    getByPriority(priority: STORAGE_QUEUE_PRIORITY): StorageQueuedOperation[];
}