/**
 * Smart cache for collection index with conditional fetching and performance optimization
 */
import { CollectionIndex } from '../types/collection.js';
import { GitHubClient } from '../collection/GitHubClient.js';
import { PerformanceMonitor } from '../utils/PerformanceMonitor.js';
import { IFileOperationsService } from '../services/FileOperationsService.js';
export declare class CollectionIndexCache {
    private cache;
    private readonly TTL;
    private readonly INDEX_URL;
    private cacheDir;
    private cacheFile;
    private githubClient;
    private performanceMonitor;
    private memoryCache;
    private fetchPromise;
    private readonly fileOperations;
    constructor(githubClient: GitHubClient, baseDir: string | undefined, performanceMonitor: PerformanceMonitor, fileOperations: IFileOperationsService);
    /**
     * Get the collection index with performance optimization and lazy loading
     */
    getIndex(lazyLoad?: boolean): Promise<CollectionIndex>;
    /**
     * Check if current cache is valid (within TTL)
     */
    private isValid;
    /**
     * Fetch fresh index from GitHub with conditional requests
     */
    private fetchFresh;
    /**
     * Validate the structure of a collection index
     */
    private validateIndexStructure;
    /**
     * Save cache to persistent storage
     */
    private saveToDisk;
    /**
     * Load cache from persistent storage
     */
    private loadFromDisk;
    /**
     * Ensure cache directory exists
     */
    private ensureCacheDir;
    /**
     * Clear all cache data with performance monitoring
     */
    clearCache(): Promise<void>;
    /**
     * Get comprehensive cache statistics for debugging and monitoring
     */
    getCacheStats(): {
        isValid: boolean;
        age: number;
        hasCache: boolean;
        elements: number;
        memoryCache: any;
        performanceMetrics: any;
    };
    /**
     * Clear in-memory cache state without touching disk.
     */
    clear(): void;
    /**
     * Fetch fresh index with comprehensive fallback strategy
     */
    private fetchFreshWithFallback;
    /**
     * Record performance metrics for cache operations
     */
    private recordPerformanceMetrics;
    /**
     * Calculate cache hit rate (placeholder for future implementation)
     */
    private calculateCacheHitRate;
    /**
     * Calculate average access time (placeholder for future implementation)
     */
    private calculateAverageAccessTime;
}
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