/**
 * Intelligent caching system for WordPress MCP Server
 * Implements multi-layer caching with TTL, LRU eviction, and site-specific keys
 */
export interface CacheEntry<T = unknown> {
    value: T;
    timestamp: number;
    ttl: number;
    etag?: string | undefined;
    lastModified?: string | undefined;
    accessCount: number;
    lastAccessed: number;
}
export interface CacheStats {
    hits: number;
    misses: number;
    evictions: number;
    expirations: number;
    totalSize: number;
    hitRate: number;
}
export interface CacheConfig {
    maxSize: number;
    defaultTTL: number;
    enableLRU: boolean;
    enableStats: boolean;
    sitePrefix?: string;
}
/**
 * High-performance in-memory cache with TTL and LRU eviction
 */
export declare class CacheManager {
    private config;
    private cache;
    private accessOrder;
    private cleanupInterval;
    private stats;
    constructor(config: CacheConfig);
    /**
     * Generate cache key with site prefix and parameter hash
     * Uses fast non-cryptographic hash (FNV-1a) for 3-5x better performance
     */
    generateKey(siteId: string, endpoint: string, params?: Record<string, unknown>): string;
    /**
     * Fast non-cryptographic hash function (FNV-1a variant)
     * 3-5x faster than MD5 for cache key generation
     * Returns base36 string for compact keys with low collision risk
     */
    private fastHash;
    /**
     * Get value from cache if not expired
     */
    get<T>(key: string): T | null;
    /**
     * Set value in cache with TTL
     */
    set<T>(key: string, value: T, ttl?: number, etag?: string, lastModified?: string): void;
    /**
     * Check if cache entry exists and is valid
     */
    has(key: string): boolean;
    /**
     * Delete specific cache entry
     */
    delete(key: string): boolean;
    /**
     * Clear all cache entries
     */
    clear(): void;
    /**
     * Clear cache entries for specific site
     */
    clearSite(siteId: string): number;
    /**
     * Clear cache entries matching pattern
     */
    clearPattern(pattern: RegExp): number;
    /**
     * Get cache statistics
     */
    getStats(): CacheStats;
    /**
     * Get cache entry with metadata
     */
    getEntry(key: string): CacheEntry | null;
    /**
     * Inspect an entry's freshness without evicting it if expired, recording
     * the same hit/miss statistics get() would. Unlike get(), a stale entry
     * is not deleted here — the caller (the HTTP cache layer) may still need
     * its ETag/Last-Modified to issue a conditional revalidation request.
     * get() itself deletes expired entries as a side effect of checking
     * freshness, which would destroy those validators before they could be
     * used, so callers that need to revalidate a stale entry must use this
     * instead of get() + a separate expired-entry lookup.
     */
    peek(key: string): {
        entry: CacheEntry | null;
        fresh: boolean;
    };
    /**
     * Check if entry supports conditional requests
     */
    supportsConditionalRequest(key: string): boolean;
    /**
     * Get conditional request headers
     */
    getConditionalHeaders(key: string): Record<string, string>;
    /**
     * Check if entry is expired
     */
    private isExpired;
    /**
     * Evict least recently used entry
     */
    private evictLRU;
    /**
     * Update access order for LRU tracking
     */
    private updateAccessOrder;
    /**
     * Remove key from access order
     */
    private removeFromAccessOrder;
    /**
     * Normalize parameters for consistent hashing
     */
    private normalizeParams;
    /**
     * Update hit rate calculation
     */
    private updateHitRate;
    /**
     * Start periodic cleanup of expired entries
     * Note: This uses setInterval and is not called in test environments to avoid Jest timer issues
     */
    private startCleanupInterval;
    /**
     * Stop the cleanup interval and clean up resources
     */
    destroy(): void;
    /**
     * Remove expired entries
     */
    private cleanupExpired;
}
/**
 * Cache configuration presets for different data types
 */
export declare const CachePresets: {
    STATIC: {
        ttl: number;
        cacheControl: string;
    };
    SEMI_STATIC: {
        ttl: number;
        cacheControl: string;
    };
    DYNAMIC: {
        ttl: number;
        cacheControl: string;
    };
    SESSION: {
        ttl: number;
        cacheControl: string;
    };
    REALTIME: {
        ttl: number;
        cacheControl: string;
    };
};
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