/**
 * Regression Trend Analyzer
 *
 * Analyzes metric trends to predict potential regressions.
 * Uses linear regression and change point detection.
 */
import type { TimeSeriesPoint, RegressionTrend, RegressionDetection } from './types.js';
/**
 * Trend analysis result
 */
export interface TrendAnalysis {
    /** Slope of trend */
    slope: number;
    /** Intercept */
    intercept: number;
    /** Correlation coefficient (R²) */
    rSquared: number;
    /** Is trend significant? */
    significant: boolean;
    /** Direction */
    direction: 'increasing' | 'decreasing' | 'stable';
    /** Projected value at future timestamp */
    project(ms: number): number;
}
/**
 * Change point detection result
 */
export interface ChangePoint {
    /** Index of change point */
    index: number;
    /** Timestamp of change */
    timestamp: number;
    /** Mean before change */
    beforeMean: number;
    /** Mean after change */
    afterMean: number;
    /** Magnitude of change */
    magnitude: number;
    /** Statistical significance */
    pValue: number;
}
/**
 * Regression Trend Analyzer class
 */
export declare class RegressionTrendAnalyzer {
    /**
     * Analyze trend for a metric
     */
    analyzeTrend(data: TimeSeriesPoint[], windowMs?: number): RegressionTrend | null;
    /**
     * Perform linear regression on time series
     */
    linearRegression(data: TimeSeriesPoint[]): TrendAnalysis;
    /**
     * Detect change points in time series
     */
    detectChangePoints(data: TimeSeriesPoint[], minSegmentSize?: number): ChangePoint[];
    /**
     * Estimate p-value for change point
     */
    private estimatePValue;
    /**
     * Project trend forward
     */
    private projectTrend;
    /**
     * Get trend direction for reporting
     */
    private getTrendDirection;
    /**
     * Calculate time until threshold breach
     */
    calculateTimeToThreshold(data: TimeSeriesPoint[], threshold: number, isIncreasingBad: boolean): number | null;
    /**
     * Compare two periods for regression
     */
    comparePeriods(baseline: TimeSeriesPoint[], current: TimeSeriesPoint[], metric: string): RegressionDetection | null;
    /**
     * Infer regression type from metric name
     */
    private inferType;
    /**
     * Check if change direction indicates regression
     */
    private isRegressionDirection;
    /**
     * Normal CDF approximation
     */
    private normalCDF;
    /**
     * Get trend description
     */
    getTrendDescription(trend: RegressionTrend): string;
    /**
     * Format time to threshold
     */
    formatTimeToThreshold(ms: number): string;
}
/**
 * Create a regression trend analyzer
 */
export declare function createRegressionTrendAnalyzer(): RegressionTrendAnalyzer;