/**
 * Embedding Subprocess Client
 *
 * Manages a child process that runs the embedding model.
 * MCP server uses this for non-blocking embeddings — the server
 * starts instantly while the model loads in the background.
 *
 * Provides the standard EmbeddingGenerator interface.
 * Falls back to mock embeddings on timeout or worker failure.
 *
 * @module @aitytech/agentkits-memory/embeddings/embedding-subprocess
 */
import type { EmbeddingGenerator } from '../types.js';
/**
 * Configuration for the embedding subprocess
 */
export interface EmbeddingSubprocessConfig {
    /** Cache directory for the embedding model */
    cacheDir: string;
    /** Vector dimensions (default: 384) */
    dimensions?: number;
    /** Timeout for worker initialization in ms (default: 60000) */
    initTimeout?: number;
    /** Timeout for individual embed requests in ms (default: 30000) */
    requestTimeout?: number;
}
/**
 * Embedding subprocess client.
 *
 * Spawns a child process that loads the embedding model.
 * Requests are queued until the worker is ready.
 * Falls back to mock embeddings on timeout.
 */
export declare class EmbeddingSubprocess {
    private child;
    private ready;
    private pending;
    private queue;
    private requestCounter;
    private respawnCount;
    private shuttingDown;
    private initTimer;
    private readonly dimensions;
    private readonly cacheDir;
    private readonly initTimeout;
    private readonly requestTimeout;
    private readonly maxRespawns;
    constructor(config: EmbeddingSubprocessConfig);
    /**
     * Spawn the embedding worker process. Returns immediately.
     * The worker loads the model in the background.
     */
    spawn(): void;
    /**
     * Handle IPC message from worker
     */
    private handleMessage;
    /**
     * Send all queued requests to the worker
     */
    private drainQueue;
    /**
     * Resolve all pending and queued requests with mock embeddings
     */
    private resolveAllWithMock;
    /**
     * Generate embedding for text.
     * Queues the request if worker is not ready yet.
     * Falls back to mock on timeout.
     */
    embed(text: string): Promise<Float32Array>;
    /**
     * Get an EmbeddingGenerator function compatible with ProjectMemoryService
     */
    getGenerator(): EmbeddingGenerator;
    /**
     * Whether the worker is ready to process requests
     */
    isReady(): boolean;
    /**
     * Shutdown the worker gracefully
     */
    shutdown(): Promise<void>;
}
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