import { EventEmitter } from 'events';
import type { Express } from 'express';
import type { GrafservBase } from 'grafserv';
import type { Server as HttpServer } from 'http';
import { LRUCache } from 'lru-cache';
import type { PostGraphileInstance } from 'postgraphile';
export declare const ONE_HOUR_MS: number;
export declare const FIVE_MINUTES_MS: number;
export type EvictionReason = 'lru' | 'ttl' | 'manual';
export interface CacheEvictionEvent {
    key: string;
    reason: EvictionReason;
    entry: GraphileCacheEntry;
}
export declare class CacheEventEmitter extends EventEmitter {
    emitEviction(event: CacheEvictionEvent): void;
    onEviction(handler: (event: CacheEvictionEvent) => void): void;
}
export declare const cacheEvents: CacheEventEmitter;
export interface CacheConfig {
    max: number;
    ttl: number;
}
/**
 * Get cache configuration from environment variables
 *
 * Supports:
 * - GRAPHILE_CACHE_MAX: Maximum number of entries (default: 50)
 * - GRAPHILE_CACHE_TTL_MS: TTL in milliseconds
 *   - Production default: ONE_YEAR
 *   - Development default: FIVE_MINUTES_MS
 *
 * NOTE: This value should be <= PG_CACHE_MAX (also default: 50) so that
 * every cached PostGraphile instance has a live pool backing it.
 */
export declare function getCacheConfig(): CacheConfig;
/**
 * Cache entry for PostGraphile v5 instances
 *
 * Each entry contains:
 * - pgl: The PostGraphile instance (manages schema, plugins, etc.)
 * - serv: The Grafserv server instance (handles HTTP/WS)
 * - handler: Express app for routing requests
 * - httpServer: Node HTTP server (required by grafserv)
 * - cacheKey: Unique identifier for this entry
 * - createdAt: Timestamp when this entry was created
 */
export interface GraphileCacheEntry {
    pgl: PostGraphileInstance;
    serv: GrafservBase;
    handler: Express;
    httpServer: HttpServer;
    cacheKey: string;
    createdAt: number;
    /** Optional RealtimeManager for cursor-tracked subscription delivery */
    realtimeManager?: {
        stop(): Promise<void>;
    } | null;
}
export declare const graphileCache: LRUCache<string, GraphileCacheEntry, unknown>;
export interface CacheStats {
    size: number;
    max: number;
    ttl: number;
    keys: string[];
}
/**
 * Get current cache statistics
 */
export declare function getCacheStats(): CacheStats;
/**
 * Clear cache entries matching a regex pattern
 *
 * @param pattern - RegExp to match against cache keys
 * @returns Number of entries cleared
 */
export declare function clearMatchingEntries(pattern: RegExp): number;
/**
 * Close all caches and release resources
 *
 * This function:
 * 1. Disposes all PostGraphile v5 instances (async)
 * 2. Clears the graphile cache
 * 3. Closes all pg pools via pgCache
 *
 * The function is idempotent - calling it multiple times
 * returns the same promise.
 */
export declare const closeAllCaches: (verbose?: boolean) => Promise<void>;