/**
 * 性能指标收集系统
 * 收集请求数、响应时间、错误率等指标
 */
export interface MetricValue {
    value: number;
    timestamp: number;
    labels?: Record<string, string>;
}
export interface Metric {
    name: string;
    type: "counter" | "gauge" | "histogram";
    help: string;
    values: MetricValue[];
    labels?: Record<string, string>;
}
/**
 * 指标收集器
 */
export declare class MetricsCollector {
    private metrics;
    private readonly maxSamples;
    /**
     * 增加计数器
     */
    increment(name: string, value?: number, labels?: Record<string, string>): void;
    /**
     * 设置仪表值
     */
    set(name: string, value: number, labels?: Record<string, string>): void;
    /**
     * 记录直方图值
     */
    observe(name: string, value: number, labels?: Record<string, string>): void;
    /**
     * 获取或创建指标
     */
    private getOrCreateMetric;
    /**
     * 获取指标键
     */
    private getMetricKey;
    /**
     * 修剪样本数量
     */
    private trimSamples;
    /**
     * 获取指标
     */
    getMetric(name: string, labels?: Record<string, string>): Metric | undefined;
    /**
     * 获取所有指标
     */
    getAllMetrics(): Metric[];
    /**
     * 获取最新值
     */
    getLatestValue(name: string, labels?: Record<string, string>): number | undefined;
    /**
     * 计算平均值
     */
    getAverage(name: string, labels?: Record<string, string>, windowMs?: number): number | undefined;
    /**
     * 计算总和
     */
    getSum(name: string, labels?: Record<string, string>, windowMs?: number): number | undefined;
    /**
     * 导出为 Prometheus 格式
     */
    exportPrometheus(): string;
    /**
     * 清理过期数据
     */
    cleanup(maxAge?: number): void;
    /**
     * 重置所有指标
     */
    reset(): void;
}
export declare const metrics: MetricsCollector;