/**
 * @file Critical Rendering Path Analyzer
 * @description Analyzes and optimizes the critical rendering path for faster
 * First Contentful Paint (FCP) and Largest Contentful Paint (LCP).
 *
 * Features:
 * - Render blocking resource detection
 * - Critical CSS extraction hints
 * - Resource prioritization
 * - Preload/prefetch recommendations
 * - DOM depth analysis
 * - Above-the-fold optimization
 */
/**
 * Resource criticality level
 */
export type CriticalityLevel = 'critical' | 'high' | 'medium' | 'low' | 'non-critical';
/**
 * Resource type
 */
export type ResourceType = 'script' | 'style' | 'font' | 'image' | 'other';
/**
 * Render blocking resource
 */
export interface RenderBlockingResource {
    url: string;
    type: ResourceType;
    size: number;
    loadTime: number;
    blockingTime: number;
    suggestions: string[];
}
/**
 * Critical resource
 */
export interface CriticalResource {
    url: string;
    type: ResourceType;
    criticality: CriticalityLevel;
    size: number;
    loadTime: number;
    inViewport: boolean;
    aboveTheFold: boolean;
    recommendations: ResourceRecommendation[];
}
/**
 * Resource recommendation
 */
export interface ResourceRecommendation {
    action: 'preload' | 'prefetch' | 'defer' | 'async' | 'inline' | 'lazy' | 'remove';
    reason: string;
    priority: 'high' | 'medium' | 'low';
    estimatedImpact: number;
}
/**
 * DOM analysis result
 */
export interface DOMAnalysis {
    totalNodes: number;
    maxDepth: number;
    widestLevel: number;
    widestLevelNodeCount: number;
    aboveTheFoldNodes: number;
    recommendations: string[];
}
/**
 * Critical path analysis result
 */
export interface CriticalPathAnalysis {
    renderBlockingResources: RenderBlockingResource[];
    criticalResources: CriticalResource[];
    domAnalysis: DOMAnalysis;
    estimatedFCP: number;
    estimatedLCP: number;
    optimizations: CriticalPathOptimization[];
    score: number;
    timestamp: number;
}
/**
 * Critical path optimization
 */
export interface CriticalPathOptimization {
    type: string;
    description: string;
    impact: 'high' | 'medium' | 'low';
    estimatedSavings: number;
    implementation: string;
}
/**
 * Analyzer configuration
 */
export interface CriticalPathAnalyzerConfig {
    /** Enable analysis */
    enabled: boolean;
    /** Viewport height for above-the-fold detection */
    viewportHeight: number;
    /** Consider render-blocking if blocks for more than this (ms) */
    blockingThreshold: number;
    /** Enable DOM analysis */
    analyzeDom: boolean;
    /** Enable resource analysis */
    analyzeResources: boolean;
    /** Debug mode */
    debug: boolean;
}
/**
 * Analyzes critical rendering path
 */
export declare class CriticalPathAnalyzer {
    private config;
    constructor(config?: Partial<CriticalPathAnalyzerConfig>);
    /**
     * Run full critical path analysis
     */
    analyze(): CriticalPathAnalysis;
    /**
     * Find render-blocking resources
     */
    findRenderBlockingResources(): RenderBlockingResource[];
    /**
     * Analyze critical resources
     */
    analyzeCriticalResources(): CriticalResource[];
    /**
     * Analyze DOM structure
     */
    analyzeDOM(): DOMAnalysis;
    /**
     * Get preload recommendations
     */
    getPreloadRecommendations(): ResourceRecommendation[];
    private getResourceTiming;
    private isInViewport;
    private getStylesheetSuggestions;
    private getScriptSuggestions;
    private getImageRecommendations;
    private getFontRecommendations;
    private generateOptimizations;
    private calculateScore;
    private estimateFCP;
    private estimateLCP;
    private getEmptyDOMAnalysis;
}
/**
 * Get or create the global critical path analyzer
 */
export declare function getCriticalPathAnalyzer(config?: Partial<CriticalPathAnalyzerConfig>): CriticalPathAnalyzer;
/**
 * Generate critical CSS extraction hints
 */
export declare function generateCriticalCSSHints(): string[];
/**
 * Check if a resource should be preloaded
 */
export declare function shouldPreload(resource: CriticalResource, currentPreloads: string[]): boolean;