import { BaseExtractor, ExtractorOptions } from './_base';
import { ExtractorResult } from '../types/extractors';
export declare class YoutubeExtractor extends BaseExtractor {
    private videoElement;
    private inlineJsonCache;
    protected schemaOrgData: any;
    constructor(document: Document, url: string, schemaOrgData?: any, options?: ExtractorOptions);
    canExtract(): boolean;
    canExtractAsync(): boolean;
    prefersAsync(): boolean;
    extract(): ExtractorResult;
    extractAsync(): Promise<ExtractorResult>;
    private normalizeLanguageCode;
    private languageCodeMatchesPreference;
    private shouldUseExistingDomTranscript;
    private getCaptionTracks;
    private findPreferredCaptionTrack;
    private pickCaptionTrack;
    private getTrackDisplayName;
    private normalizeLanguageLabel;
    private getTranscriptLanguageCodeFromDom;
    private getInlineChapters;
    private getTranscriptContainer;
    private getTranscriptSelectors;
    private buildTranscriptFromContainer;
    private extractTranscriptFromExistingDom;
    private canOpenTranscriptPanel;
    private buildResult;
    private formatDescription;
    private getVideoData;
    private getChannelName;
    private getChannelNameFromDom;
    private getChannelNameFromMicrodata;
    private getChannelNameFromPlayerResponse;
    /** Returns ytInitialPlayerResponse only if its video ID matches the current URL (stale after SPA navigation). */
    private getValidatedPlayerResponse;
    private parseInlineJson;
    private fetchTranscript;
    private getInlineCaptionTrack;
    private fetchCaptionXml;
    private pollFor;
    private waitForTranscriptSegments;
    private waitForTranscriptContainer;
    private waitForElement;
    private isMobileYoutube;
    /**
     * Fallback: open YouTube's transcript panel and read segments from the DOM.
     * Used when fetch-based extraction fails and the transcript is not already rendered.
     */
    private extractTranscriptFromOpenedDom;
    /**
     * Mobile YouTube (m.youtube.com) transcript panel opening flow:
     * 1. Click "...more" to expand description
     * 2. Click "View all" next to Chapters to open the engagement panel
     * 3. Click "Timeline" tab to switch to the transcript view
     * 4. Wait for transcript segments to render
     */
    private openMobileTranscriptPanel;
    private fetchPlayerData;
    private fetchChapters;
    private extractChaptersFromPlayerBar;
    private extractChaptersFromEngagementPanels;
    private parseTimestamp;
    private parseTranscriptXml;
    private decodeEntities;
    private _videoId;
    private getVideoId;
    /**
     * Group raw transcript segments into readable blocks.
     * If speaker markers (>> or -) are present, groups by speaker turn.
     * Otherwise, groups by sentence boundaries.
     */
    private groupTranscriptSegments;
    /**
     * Group segments by speaker turns, then by sentences within each turn.
     * Each ">>" or "- " marker starts a new speaker turn (with blank line separation).
     * Within a turn, text is split at sentence boundaries for readability.
     * Tracks alternating speaker identity (0/1).
     */
    private groupBySpeaker;
    /**
     * Split turns that start with a short affirmative response (e.g. "Mhm.", "Yeah.")
     * followed by longer content. The affirmative belongs to the current speaker,
     * but the rest is likely the other speaker (missed diarization in auto-captions).
     */
    private splitAffirmativeTurns;
    private mergeSentenceGroupsWithinTurn;
    private shouldMergeSentenceGroups;
    private isShortStandaloneUtterance;
    /**
     * Group segments by sentence boundaries for transcripts without speaker markers.
     * Accumulates text until a segment ends with sentence-ending punctuation (.!?),
     * or until a very large time gap between segments.
     */
    private groupBySentence;
    /**
     * Find the best natural break point in a list of segments.
     * Prefers mid-text sentence boundaries (". A") over gap-based breaks.
     * May splice a segment in two when a sentence boundary is found mid-text.
     * Returns the index to break BEFORE (i.e., flush segments 0..idx-1).
     */
    private findNaturalBreak;
}