/**
 * Prompt Cache Module
 *
 * Simple LRU cache for frequently accessed prompts.
 * Reduces database queries for repeated prompt lookups.
 */
import type { PromptRecord } from '../llm_api/types.js';
/**
 * Cache configuration options
 */
export interface PromptCacheConfig {
    /** Time-to-live in milliseconds (default: 5 minutes) */
    ttl_ms?: number;
    /** Maximum number of entries (default: 100) */
    max_size?: number;
    /** Whether caching is enabled (default: true) */
    enabled?: boolean;
}
/**
 * Cache statistics
 */
export interface CacheStats {
    hits: number;
    misses: number;
    size: number;
    max_size: number;
    hit_rate: number;
}
/**
 * Simple LRU cache for prompts
 *
 * @example
 * ```typescript
 * const cache = new PromptCache({ ttl_ms: 60000, max_size: 50 });
 *
 * // Check cache first
 * const cached = cache.get('marketing', 'greeting');
 * if (cached) {
 *   return cached;
 * }
 *
 * // Fetch from database and cache
 * const prompt = get_prompt_by_area_and_key(db, 'marketing', 'greeting', logger);
 * if (prompt) {
 *   cache.set(prompt);
 * }
 * ```
 */
export declare class PromptCache {
    private cache;
    private ttl_ms;
    private max_size;
    private enabled;
    private hits;
    private misses;
    constructor(config?: PromptCacheConfig);
    /**
     * Generate cache key from area and key
     */
    private make_key;
    /**
     * Check if an entry is expired
     */
    private is_expired;
    /**
     * Evict least recently used entries if cache is full
     */
    private evict_if_needed;
    /**
     * Get a prompt from the cache
     *
     * @param area - Prompt area
     * @param key - Prompt key
     * @returns Cached prompt or null if not found/expired
     */
    get(area: string, key: string): PromptRecord | null;
    /**
     * Get a prompt by ID from the cache
     *
     * @param id - Prompt ID (UUID)
     * @returns Cached prompt or null if not found/expired
     */
    get_by_id(id: string): PromptRecord | null;
    /**
     * Add a prompt to the cache
     *
     * @param prompt - Prompt record to cache
     */
    set(prompt: PromptRecord): void;
    /**
     * Remove a prompt from the cache
     *
     * @param area - Prompt area
     * @param key - Prompt key
     */
    invalidate(area: string, key: string): void;
    /**
     * Remove a prompt by ID from the cache
     *
     * @param id - Prompt ID (UUID)
     */
    invalidate_by_id(id: string): void;
    /**
     * Invalidate all prompts in an area
     *
     * @param area - Prompt area to invalidate
     */
    invalidate_area(area: string): void;
    /**
     * Clear all cached entries
     */
    clear(): void;
    /**
     * Remove all expired entries
     *
     * @returns Number of entries removed
     */
    cleanup(): number;
    /**
     * Get cache statistics
     */
    get_stats(): CacheStats;
    /**
     * Enable or disable the cache
     *
     * @param enabled - Whether to enable caching
     */
    set_enabled(enabled: boolean): void;
    /**
     * Check if caching is enabled
     */
    is_enabled(): boolean;
}
/**
 * Get the global prompt cache instance
 * Creates one with default settings if not configured
 *
 * @returns Global prompt cache
 */
export declare function get_prompt_cache(): PromptCache;
/**
 * Configure the global prompt cache
 *
 * @param config - Cache configuration options
 */
export declare function configure_prompt_cache(config: PromptCacheConfig): void;
/**
 * Clear the global prompt cache
 */
export declare function clear_prompt_cache(): void;
/**
 * Invalidate a specific prompt in the global cache by area and key
 *
 * @param area - Prompt area
 * @param key - Prompt key
 */
export declare function invalidate_prompt_cache(area: string, key: string): void;
/**
 * Invalidate a specific prompt in the global cache by ID
 *
 * @param id - Prompt ID (UUID)
 */
export declare function invalidate_prompt_cache_by_id(id: string): void;
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