/**
 * Persistent Embedding Cache
 *
 * SQLite-backed cache for embeddings to avoid re-computing
 * embeddings for the same text content.
 *
 * @module @aitytech/agentkits-memory/embeddings
 */
import type { Database as BetterDatabase } from 'better-sqlite3';
/**
 * Embedding cache configuration
 */
export interface PersistentEmbeddingCacheConfig {
    /** Maximum number of entries (default: 10000) */
    maxSize?: number;
    /** TTL in milliseconds (default: 7 days) */
    ttlMs?: number;
    /** Vector dimensions (default: 384) */
    dimensions?: number;
}
/**
 * Cached embedding entry
 */
export interface CachedEmbedding {
    /** Content hash (primary key) */
    hash: string;
    /** The embedding vector */
    embedding: Float32Array;
    /** When the entry was created */
    createdAt: number;
    /** When the entry expires */
    expiresAt: number;
    /** Access count */
    accessCount: number;
}
/**
 * Cache statistics
 */
export interface PersistentEmbeddingCacheStats {
    /** Total entries in cache */
    size: number;
    /** Cache hits */
    hits: number;
    /** Cache misses */
    misses: number;
    /** Hit rate (0-1) */
    hitRate: number;
    /** Total bytes used */
    bytesUsed: number;
    /** Oldest entry age in ms */
    oldestEntryAge: number;
}
/**
 * Persistent Embedding Cache using SQLite
 */
export declare class PersistentEmbeddingCache {
    private db;
    private config;
    private stats;
    constructor(db: BetterDatabase, config?: PersistentEmbeddingCacheConfig);
    /**
     * Initialize the cache table
     */
    private initializeSchema;
    /**
     * Hash content for cache key
     */
    private hashContent;
    /**
     * Convert Float32Array to Buffer for storage
     */
    private toBuffer;
    /**
     * Convert Buffer back to Float32Array
     */
    private fromBuffer;
    /**
     * Get embedding from cache
     */
    get(content: string): Float32Array | null;
    /**
     * Store embedding in cache
     */
    set(content: string, embedding: Float32Array): void;
    /**
     * Check if content is in cache
     */
    has(content: string): boolean;
    /**
     * Delete expired entries
     */
    evictExpired(): number;
    /**
     * Evict oldest entries if over capacity
     */
    private evictIfNeeded;
    /**
     * Clear all cache entries
     */
    clear(): void;
    /**
     * Get cache statistics
     */
    getStats(): PersistentEmbeddingCacheStats;
    /**
     * Get all cached embeddings
     */
    getAllEmbeddings(): Array<{
        hash: string;
        embedding: Float32Array;
    }>;
}
/**
 * Create a persistent embedding cache
 *
 * @example
 * ```typescript
 * import Database from 'better-sqlite3';
 * import { createPersistentEmbeddingCache } from '@aitytech/agentkits-memory/embeddings';
 *
 * const db = new Database(':memory:');
 *
 * const cache = createPersistentEmbeddingCache(db, {
 *   maxSize: 10000,
 *   ttlMs: 7 * 24 * 60 * 60 * 1000, // 7 days
 * });
 * ```
 */
export declare function createPersistentEmbeddingCache(db: BetterDatabase, config?: PersistentEmbeddingCacheConfig): PersistentEmbeddingCache;
export default PersistentEmbeddingCache;
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