/**
 * @file Enhanced Vitals Collector
 * @description Extended Core Web Vitals collection with advanced attribution,
 * custom metrics, and detailed analysis.
 *
 * Features:
 * - Core Web Vitals (LCP, FID, CLS, INP, FCP, TTFB)
 * - Custom metric definitions
 * - Attribution analysis
 * - Element-level tracking
 * - Historical comparison
 * - Threshold management
 */
/**
 * Metric name type
 */
export type MetricName = 'LCP' | 'FID' | 'CLS' | 'INP' | 'FCP' | 'TTFB' | 'FMP' | 'TTI' | 'TBT' | 'custom';
/**
 * Metric rating
 */
export type MetricRating = 'good' | 'needs-improvement' | 'poor';
/**
 * Collected metric data
 */
export interface CollectedMetric {
    name: MetricName | string;
    value: number;
    rating: MetricRating;
    delta: number;
    id: string;
    navigationType: string;
    timestamp: number;
    attribution: MetricAttribution | null;
    entries: PerformanceEntry[];
}
/**
 * Metric attribution data
 */
export interface MetricAttribution {
    element?: string;
    url?: string;
    timeToFirstByte?: number;
    resourceLoadDelay?: number;
    elementRenderDelay?: number;
    lcpResourceEntry?: PerformanceResourceTiming;
    largestShiftTarget?: string;
    largestShiftTime?: number;
    loadState?: string;
    eventTarget?: string;
    eventType?: string;
    eventTime?: number;
    nextPaintTime?: number;
}
/**
 * Metric thresholds
 */
export interface MetricThresholds {
    good: number;
    poor: number;
}
/**
 * Collection configuration
 */
export interface VitalsCollectionConfig {
    /** Enable collection */
    enabled: boolean;
    /** Metrics to collect */
    metrics: MetricName[];
    /** Custom thresholds */
    thresholds?: Partial<Record<MetricName, MetricThresholds>>;
    /** Enable attribution */
    attribution: boolean;
    /** Sample rate (0-1) */
    sampleRate: number;
    /** Report endpoint */
    reportEndpoint?: string;
    /** Batch reports */
    batchReports: boolean;
    /** Batch interval in ms */
    batchInterval: number;
    /** Debug mode */
    debug: boolean;
}
/**
 * Metric callback
 */
export type MetricCallback = (metric: CollectedMetric) => void;
/**
 * Default thresholds based on Google recommendations
 */
export declare const DEFAULT_THRESHOLDS: Record<MetricName, MetricThresholds>;
/**
 * Enhanced vitals collection with attribution
 */
export declare class EnhancedVitalsCollector {
    private config;
    private thresholds;
    private metrics;
    private callbacks;
    private reportBuffer;
    private flushTimer;
    private observers;
    private isInitialized;
    constructor(config?: Partial<VitalsCollectionConfig>);
    /**
     * Initialize vitals collection
     */
    init(): () => void;
    /**
     * Subscribe to metric updates
     */
    subscribe(callback: MetricCallback): () => void;
    /**
     * Get all collected metrics
     */
    getMetrics(): Map<string, CollectedMetric[]>;
    /**
     * Get specific metric
     */
    getMetric(name: MetricName): CollectedMetric[];
    /**
     * Get latest value for a metric
     */
    getLatestValue(name: MetricName): CollectedMetric | null;
    /**
     * Track a custom metric
     */
    trackCustomMetric(name: string, value: number, thresholds?: MetricThresholds): void;
    /**
     * Start a custom timing
     */
    startTiming(name: string): () => void;
    /**
     * Flush any pending reports
     */
    flush(): void;
    /**
     * Get summary statistics
     */
    getSummary(): Record<string, {
        value: number;
        rating: MetricRating;
    } | null>;
    /**
     * Calculate overall performance score
     */
    calculateScore(): number;
    private setupMetricCollection;
    private observeLCP;
    private observeFID;
    private observeCLS;
    private observeINP;
    private observeFCP;
    private observeTTFB;
    private recordMetric;
    private calculateRating;
    private ratingToScore;
    private getElementSelector;
    private getNavigationType;
    private setupLifecycleHandlers;
    private startBatchFlush;
    /**
     * Send collected metrics to the reporting endpoint.
     *
     * Note: This method intentionally uses raw fetch/sendBeacon because:
     * 1. Web Vitals reporting should be independent of the main API client
     * 2. Uses keepalive/sendBeacon for reliability when page is unloading
     * 3. Reporting endpoints are often third-party analytics services
     *
     * @see {@link @/lib/api/api-client} for application API calls
     */
    private sendToEndpoint;
    private cleanup;
    private generateId;
    private log;
}
/**
 * Get or create the global vitals collector
 */
export declare function getEnhancedVitalsCollector(config?: Partial<VitalsCollectionConfig>): EnhancedVitalsCollector;
/**
 * Reset the collector instance
 */
export declare function resetEnhancedVitalsCollector(): void;