/**
 * Task Retrieval Service - Centralized task retrieval logic
 *
 * REFACTORED: Extracted from TaskManager.getCurrentTask() for Phase 4.
 * Handles retrieving current task from queue (preferred) or file (fallback).
 * Includes retry logic, file sync, validation, and backward compatibility.
 *
 * @internal
 * @requirement REFACTOR-EXTRACT-TASK-CRUD-SERVICES - Phase 4: Extract Task CRUD Services
 */
import type { Task } from '@shadel/workflow-core';
import { TaskQueueManager } from './task-queue.js';
import { TaskFileSync } from './task-file-sync.js';
import { TaskValidator } from './task-validator.js';
import { TaskMigration } from '../utils/migration.js';
/**
 * Task Retrieval Service
 *
 * Centralizes task retrieval logic with queue/file sync, validation, and backward compatibility.
 */
export declare class TaskRetrievalService {
    private queueManager;
    private fileSync;
    private validator;
    private migration;
    private taskFile;
    private migrationChecked;
    private syncFileFromQueue;
    constructor(queueManager: TaskQueueManager, fileSync: TaskFileSync, validator: TaskValidator, migration: TaskMigration, taskFile: string, syncFileFromQueueFn: (queueTask: any, preserveFields: string[]) => Promise<void>);
    /**
     * Check and run migration if needed (only once per instance)
     */
    private ensureMigration;
    /**
     * Get current active task
     *
     * Retrieves task from queue (preferred) or file (fallback).
     * Handles queue/file sync, validation, and backward compatibility.
     *
     * @returns Current task or null if no active task
     * @throws Error if task loading fails
     */
    getCurrentTask(): Promise<Task | null>;
}