/**
 * SMI-644: Enhanced Tiered Cache with TTL Management
 * L1 (memory) + L2 (SQLite) with automatic promotion/demotion
 */
import type { SearchResult } from './lru.js';
import { TTLTier } from './CacheEntry.js';
/** L1 cache configuration */
export interface L1Config {
    maxEntries?: number;
    maxMemoryBytes?: number;
}
/** L2 cache configuration */
export interface L2Config {
    dbPath: string;
    pruneIntervalMs?: number;
}
/** Combined tiered cache configuration */
export interface TieredCacheConfig {
    l1?: L1Config;
    l2?: L2Config;
    enablePromotion?: boolean;
    enableDemotion?: boolean;
}
/** Cache statistics */
export interface TieredCacheStats {
    l1Hits: number;
    l1Misses: number;
    l2Hits: number;
    l2Misses: number;
    totalHits: number;
    totalMisses: number;
    hitRate: number;
    l1Size: number;
    l2Size: number;
    promotions: number;
    demotions: number;
    evictions: number;
    popularEntries: number;
    rareEntries: number;
}
/**
 * Enhanced two-tier cache with TTL management
 */
export declare class EnhancedTieredCache {
    private l1;
    private db;
    private config;
    private pruneTimer;
    private stats;
    private stmts;
    /**
     * @deprecated If l2.dbPath is passed, use EnhancedTieredCache.create(config) instead —
     * the async factory supports both native and WASM SQLite. Passing l2.dbPath to this
     * constructor throws to prevent silent data loss.
     */
    constructor(config?: TieredCacheConfig);
    /**
     * Async factory — supports both native and WASM SQLite.
     *
     * @param config - Cache configuration; l2.dbPath is opened via createDatabaseAsync
     * @returns Fully initialised EnhancedTieredCache instance
     */
    static create(config?: TieredCacheConfig): Promise<EnhancedTieredCache>;
    private initFromConfig;
    private initL2Async;
    /**
     * Get entry from cache (L1 first, then L2)
     */
    get(key: string): {
        results: SearchResult[];
        totalCount: number;
    } | undefined;
    /**
     * Store entry in cache
     */
    set(key: string, results: SearchResult[], totalCount: number, ttlTier?: TTLTier): void;
    /**
     * Check if key exists in cache
     */
    has(key: string): boolean;
    /**
     * Delete specific entry
     */
    delete(key: string): boolean;
    /**
     * Invalidate all entries (called on index update)
     */
    invalidateAll(): void;
    /**
     * Prune expired entries
     */
    prune(): number;
    /**
     * Get entries that need background refresh
     */
    getEntriesNeedingRefresh(): string[];
    /**
     * Get cache statistics
     */
    getStats(): TieredCacheStats;
    /**
     * Demote entry from L1 to L2
     */
    private demoteToL2;
    /**
     * Close cache and cleanup resources
     */
    close(): void;
}
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