/**
 * Metrics Collection and Monitoring
 * Comprehensive observability for lock operations
 */
import { EventEmitter } from "events";
import { LockMetrics, CircuitBreakerMetrics } from "../core/types";
export type { CircuitBreakerMetrics } from "../core/types";
/**
 * Histogram for measuring operation latencies
 */
declare class Histogram {
    private buckets;
    private sum;
    private count;
    constructor(buckets?: number[]);
    /**
     * Record a measurement
     */
    observe(value: number): void;
    /**
     * Get percentile value
     */
    getPercentile(percentile: number): number;
    /**
     * Get average value
     */
    getAverage(): number;
    /**
     * Get summary statistics
     */
    getSummary(): {
        count: number;
        sum: number;
        average: number;
        p50: number;
        p90: number;
        p95: number;
        p99: number;
    };
    /**
     * Reset histogram
     */
    reset(): void;
}
/**
 * Comprehensive metrics collector for NeoLock
 */
export declare class MetricsCollector extends EventEmitter {
    private locksAcquired;
    private locksReleased;
    private lockExtensions;
    private failedAcquisitions;
    private retriesTotal;
    private activeLocks;
    private lockDuration;
    private acquisitionLatency;
    private releaseLatency;
    private extensionLatency;
    private circuitBreakerMetrics;
    private activeLocksMap;
    private startTime;
    private evictionTimer?;
    /**
     * Record lock acquisition
     */
    recordLockAcquired(identifier: string, resources: string[], acquisitionLatencyMs: number, ttl?: number): void;
    /**
     * Record lock release
     */
    recordLockReleased(identifier: string, releaseLatencyMs: number): void;
    /**
     * Record lock extension
     */
    recordLockExtended(identifier: string, extensionLatencyMs: number): void;
    /**
     * Record failed acquisition
     */
    recordAcquisitionFailed(resources: string[], error: Error, attempts: number, totalLatencyMs: number): void;
    /**
     * Record retry attempt
     */
    recordRetry(identifier: string, attempt: number): void;
    /**
     * Update circuit breaker metrics
     */
    updateCircuitBreakerMetrics(clientId: string, metrics: CircuitBreakerMetrics): void;
    /**
     * Get comprehensive metrics
     */
    getMetrics(): LockMetrics & {
        detailed: {
            lockDurationStats: ReturnType<Histogram["getSummary"]>;
            acquisitionLatencyStats: ReturnType<Histogram["getSummary"]>;
            releaseLatencyStats: ReturnType<Histogram["getSummary"]>;
            extensionLatencyStats: ReturnType<Histogram["getSummary"]>;
            uptimeMs: number;
            activeLockDetails: Array<{
                identifier: string;
                resources: string[];
                durationMs: number;
                extensions: number;
            }>;
        };
    };
    /**
     * Get circuit breaker metrics for specific client
     */
    getCircuitBreakerMetrics(clientId: string): CircuitBreakerMetrics | undefined;
    /**
     * Get all circuit breaker metrics
     */
    getAllCircuitBreakerMetrics(): Map<string, CircuitBreakerMetrics>;
    /**
     * Get performance summary
     */
    getPerformanceSummary(): {
        successRate: number;
        averageAcquisitionLatency: number;
        averageReleaseLatency: number;
        averageLockDuration: number;
        retryRate: number;
        circuitBreakerHealth: {
            overallState: "healthy" | "degraded" | "unhealthy";
            openCircuits: number;
            totalCircuits: number;
        };
    };
    /**
     * Start periodic eviction of expired entries from activeLocksMap.
     * Runs at most once (idempotent).
     */
    private startEvictionTimer;
    /**
     * Remove locks from activeLocksMap that have expired based on
     * their acquisition time + TTL (with 2x margin for extensions).
     */
    private evictExpiredLocks;
    /**
     * Stop the eviction timer (for cleanup/shutdown).
     */
    stopEviction(): void;
    /**
     * Reset all metrics
     */
    reset(): void;
    /**
     * Export metrics in Prometheus format
     */
    exportPrometheusMetrics(): string;
}
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