/**
 * Image Cache Module
 * Caches image processing results in memory to prevent recalculation
 */
import { CacheStorageType, ImageProcessingOptions, ProcessingResult } from "./types.js";
/**
 * Image Cache Options
 */
export interface ImageCacheOptions {
    /** Maximum cache size (number of items) */
    maxSize?: number;
    /** Cache item expiry time (ms) */
    expiryTime?: number;
    /** Auto cleanup interval (ms) */
    cleanupInterval?: number;
    /** Enable debug logging */
    debug?: boolean;
    /** Cache storage type (default: MEMORY) */
    storageType?: CacheStorageType;
    /** IndexedDB database name */
    dbName?: string;
    /** IndexedDB version */
    dbVersion?: number;
}
/**
 * Image Cache Class
 *
 * Caches image processing results in memory to prevent duplicate processing
 * of the same images with the same options, improving performance.
 */
export declare class ImageCache {
    /** Cache storage */
    private cache;
    /** Cache statistics */
    private stats;
    /** Maximum cache size */
    private maxSize;
    /** Cache item expiry time (ms) */
    private expiryTime;
    /** Cleanup timer ID */
    private cleanupTimer;
    /** Debug mode */
    private debug;
    /** Cache storage type */
    private storageType;
    /** IndexedDB database name */
    private dbName;
    /** IndexedDB version */
    private dbVersion;
    /** IndexedDB database instance */
    private db;
    /** IndexedDB initialization status */
    private dbInitialized;
    /** IndexedDB initialization in progress */
    private dbInitializing;
    /** IndexedDB initialization promise */
    private dbInitPromise;
    /**
     * Image cache constructor
     * @param options Cache options
     */
    constructor(options?: ImageCacheOptions);
    /**
     * Initialize IndexedDB
     * @returns Initialization completion promise
     */
    private initIndexedDB;
    /**
     * IndexedDB cache lookup
     * @param key Cache key
     * @returns Cached result or null in a promise
     */
    private getFromIndexedDB;
    /**
     * Save image processing result to IndexedDB cache
     * @param key Cache key
     * @param item Cache item
     */
    private saveToIndexedDB;
    /**
     * Clean up expired cache items in IndexedDB
     */
    private cleanupIndexedDB;
    /**
     * Generate cache key
     * @param imageId Image identifier
     * @param options Processing options
     * @returns Cache key
     */
    private generateKey;
    /**
     * Cache image processing result
     * @param imageId Image identifier
     * @param options Processing options
     * @param result Processing result
     */
    set(imageId: string, options: ImageProcessingOptions, result: ProcessingResult): Promise<void>;
    /**
     * Lookup image processing result from cache
     * @param imageId Image identifier
     * @param options Processing options
     * @returns Cached result or null
     */
    get(imageId: string, options: ImageProcessingOptions): Promise<ProcessingResult | null>;
    /**
     * Clone result data
     * @param result Original result
     * @returns Cloned result
     */
    private cloneResult;
    /**
     * Evict LRU (Least Recently Used) item
     */
    private evictLRU;
    /**
     * Clean up expired cache items
     */
    private cleanup;
    /**
     * Return cache statistics
     * @returns Cache statistics
     */
    getStats(): {
        size: number;
        memoryHits: number;
        memoryMisses: number;
        dbHits: number;
        dbMisses: number;
        evictions: number;
        totalHits: number;
        totalMisses: number;
    };
    /**
     * Output debug log
     * @param message Log message
     */
    private logDebug;
    /**
     * Initialize cache
     */
    clear(): Promise<void>;
    /**
     * Change cache storage type
     * @param storageType New storage type
     */
    setStorageType(storageType: CacheStorageType): Promise<void>;
    /**
     * Clean up resources
     */
    dispose(): void;
}