import type { ImageGenerationRequest, ImageGenerationResult, CacheConfig } from '../types/index.js';
interface CacheStats {
    hits: number;
    misses: number;
    entries: number;
    diskUsage: number;
    oldestEntry: number;
    newestEntry: number;
}
export declare class ImageCache {
    private cache;
    private config;
    private cacheDir;
    private metadataFile;
    private stats;
    constructor(config: CacheConfig);
    /**
     * Initialize cache system
     */
    private initialize;
    /**
     * Generate cache key for a request
     */
    private generateCacheKey;
    /**
     * Check if result exists in cache
     */
    get(request: ImageGenerationRequest): Promise<ImageGenerationResult | null>;
    /**
     * Store result in cache
     */
    set(request: ImageGenerationRequest, result: ImageGenerationResult): Promise<void>;
    /**
     * Clear all cached data
     */
    clear(): Promise<void>;
    /**
     * Get cache statistics
     */
    getStats(): CacheStats;
    /**
     * Get cache hit rate
     */
    getHitRate(): number;
    /**
     * Handle expired cache entry
     */
    private handleExpiredEntry;
    /**
     * Handle deleted cache entry
     */
    private handleDeletedEntry;
    /**
     * Cleanup image files
     */
    private cleanupFiles;
    /**
     * Load metadata from disk
     */
    private loadMetadata;
    /**
     * Save metadata to disk
     */
    private saveMetadata;
    /**
     * Update disk usage statistics
     */
    private updateDiskUsage;
    /**
     * Cleanup orphaned files (files without cache entries)
     */
    private cleanupOrphanedFiles;
    /**
     * Get human-readable cache size
     */
    getFormattedDiskUsage(): string;
}
/**
 * Initialize global cache instance
 */
export declare function initializeCache(config: CacheConfig): ImageCache;
/**
 * Get global cache instance
 */
export declare function getCache(): ImageCache | null;
export default ImageCache;
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