import { youtube_v3 } from 'googleapis';
import { TranscriptSegment, TranscriptOptions, FormattedTranscript, ResearchSourceMetadata, ResearchTranscript } from './types/youtube-types.js';
interface BasicVideoInfo {
    title?: string;
    channel_id?: string;
    author?: string;
    channel?: {
        id: string;
        name: string;
        url: string;
    } | null;
    thumbnail?: Array<{
        url: string;
    }>;
}
export declare function createResearchSourceMetadata(videoId: string, basicInfo: BasicVideoInfo): ResearchSourceMetadata;
export declare class YouTubeService {
    private static readonly transcriptCache;
    private static innertubePromise?;
    youtube: youtube_v3.Youtube;
    private apiKey;
    constructor(apiKey?: string);
    get hasApiKey(): boolean;
    requireApiKey(): void;
    private getInnertube;
    private fetchTranscriptSource;
    searchVideos(query: string, maxResults?: number, options?: {
        channelId?: string;
        order?: string;
        type?: string;
        videoDuration?: string;
        publishedAfter?: string;
        publishedBefore?: string;
        videoCaption?: string;
        videoDefinition?: string;
        regionCode?: string;
    }): Promise<youtube_v3.Schema$SearchListResponse>;
    getVideoDetails(videoId: string): Promise<youtube_v3.Schema$VideoListResponse>;
    getChannelDetails(channelId: string): Promise<youtube_v3.Schema$ChannelListResponse>;
    getComments(videoId: string, maxResults?: number, options?: {
        order?: 'time' | 'relevance';
        pageToken?: string;
        includeReplies?: boolean;
    }): Promise<youtube_v3.Schema$CommentThreadListResponse>;
    getTranscript(videoId: string, language?: string): Promise<TranscriptSegment[]>;
    getTranscript(videoId: string, options: TranscriptOptions): Promise<TranscriptSegment[]>;
    getResearchTranscript(videoId: string, options?: TranscriptOptions): Promise<ResearchTranscript>;
    getEnhancedTranscript(videoId: string | string[], options?: TranscriptOptions): Promise<FormattedTranscript>;
    private processTranscript;
    private filterByTimeRange;
    private filterBySearchText;
    private formatTranscript;
    /**
     * Extracts key moments from a transcript based on content analysis
     * @param videoId Video ID to analyze
     * @param maxMoments Maximum number of key moments to extract
     * @returns A formatted transcript with key moments and their timestamps
     */
    getKeyMomentsTranscript(videoId: string, maxMoments?: number): Promise<FormattedTranscript>;
    /**
     * Divides a video transcript into segments and prepares it for segment-by-segment analysis
     * @param videoId Video ID to segment
     * @param segmentCount Number of segments to divide the transcript into
     * @returns A formatted transcript with segments marked by timestamps
     */
    getSegmentedTranscript(videoId: string, segmentCount?: number): Promise<FormattedTranscript>;
    private formatTimestamp;
    private generateTranscriptCacheKey;
    private loadTranscriptSource;
}
export {};