import { Client as ElasticClient } from '@elastic/elasticsearch';
import type { ElasticsearchConfig } from '../config/types.js';
import { HealthStatus } from './health-check.js';
import type { HealthCheckResult } from './health-check.js';
import { Logger } from '../observability/logger.js';
import { MetricsCollector } from '../observability/metrics.js';
/**
 * Connection manager configuration
 */
export interface ConnectionManagerConfig extends ElasticsearchConfig {
    /** Enable health checks */
    enableHealthCheck?: boolean;
    /** Enable circuit breaker */
    enableCircuitBreaker?: boolean;
    /** Logger instance */
    logger?: Logger;
    /** Metrics collector */
    metricsCollector?: MetricsCollector;
}
/**
 * Connection manager for Elasticsearch client
 *
 * Provides:
 * - Singleton client instance
 * - Connection pooling
 * - Health monitoring
 * - Circuit breaker pattern
 * - Automatic reconnection
 *
 * @example
 * ```typescript
 * const manager = ElasticsearchConnectionManager.getInstance({
 *   nodes: ['http://localhost:9200'],
 *   auth: { type: 'basic', username: 'elastic', password: 'changeme' }
 * });
 *
 * const client = manager.getClient();
 * await client.search({ index: 'my-index', query: { match_all: {} } });
 * ```
 */
export declare class ElasticsearchConnectionManager {
    private static instance;
    private client;
    private healthChecker;
    private circuitBreaker;
    private logger;
    private metrics;
    private config;
    private isInitialized;
    private connectionCount;
    private constructor();
    /**
     * Get singleton instance
     */
    static getInstance(config?: ConnectionManagerConfig): ElasticsearchConnectionManager;
    /**
     * Reset singleton instance (useful for testing)
     */
    static resetInstance(): void;
    /**
     * Create Elasticsearch client with configuration
     */
    private createClient;
    /**
     * Initialize connection manager
     */
    initialize(): Promise<void>;
    /**
     * Get Elasticsearch client
     */
    getClient(): ElasticClient;
    /**
     * Execute operation through circuit breaker
     */
    execute<T>(operation: () => Promise<T>): Promise<T>;
    /**
     * Health check callback
     */
    private onHealthChange;
    /**
     * Perform health check
     */
    healthCheck(): Promise<HealthCheckResult>;
    /**
     * Get current health status
     */
    getHealthStatus(): HealthStatus;
    /**
     * Check if cluster is healthy
     */
    isHealthy(): boolean;
    /**
     * Check if cluster is available
     */
    isAvailable(): boolean;
    /**
     * Get circuit breaker state
     */
    getCircuitState(): string;
    /**
     * Get connection statistics
     */
    getStats(): {
        initialized: boolean;
        connectionCount: number;
        healthStatus: HealthStatus;
        circuitState: string;
        lastHealthCheck?: HealthCheckResult;
    };
    /**
     * Cleanup and close connections
     */
    destroy(): Promise<void>;
}