/**
 * QR Video RAG - Retriever
 *
 * Retrieves knowledge from QR-encoded videos using semantic search
 */
import { VectorDatabase, Embedder, QRVideoStoreIndexEntry, SearchResult, FrameExtractionOptions } from './types';
/**
 * QR Video Store Retriever
 *
 * Performs semantic search and retrieves decoded text from QR-encoded videos
 */
export declare class QRVideoStoreRetriever {
    private database;
    private embedder;
    private verbose;
    private frameCache;
    private maxCacheSize;
    /**
     * Create a new QR Video Store Retriever
     *
     * @param database Vector database containing chunk embeddings
     * @param embedder Embedding generator for query encoding
     * @param options Optional configuration
     *
     * @example
   * ```typescript
   * const retriever = new QRVideoStoreRetriever(
   *   createSupabaseAdapter(supabase),
   *   createGeminiEmbedder(apiKey),
   *   { verbose: true, maxCacheSize: 100 }
   * );
   * ```
     */
    constructor(database: VectorDatabase, embedder: Embedder, options?: {
        verbose?: boolean;
        maxCacheSize?: number;
    });
    /**
     * Retrieve relevant chunk metadata based on semantic search
     *
     * @param query Search query text
     * @param matchCount Number of results to return
     * @returns Array of matching index entries with similarity scores
     *
     * @example
     * ```typescript
     * const matches = await retriever.retrieveChunks(
     *   "How do I configure authentication?",
     *   5
     * );
     * console.log(matches[0].similarity); // 0.85
     * ```
     */
    retrieveChunks(query: string, matchCount?: number): Promise<QRVideoStoreIndexEntry[]>;
    /**
     * Extract a specific frame from video as buffer
     *
     * @param videoPath Path to the video file
     * @param frameNumber Frame number to extract (0-indexed)
     * @returns Buffer containing PNG image data, or null if extraction fails
     *
     * @example
     * ```typescript
     * const frameBuffer = await retriever.extractFrameAsBuffer(
     *   "./knowledge.mp4",
     *   42
     * );
     * if (frameBuffer) {
     *   fs.writeFileSync("frame-42.png", frameBuffer);
     * }
     * ```
     */
    extractFrameAsBuffer(videoPath: string, frameNumber: number, options?: Partial<FrameExtractionOptions>): Promise<Buffer | null>;
    /**
     * Decode QR code from image buffer
     *
     * @param imageBuffer Buffer containing PNG/JPG image data
     * @returns Decoded text, or null if QR code cannot be read
     *
     * @example
     * ```typescript
     * const qrImage = fs.readFileSync("qr-code.png");
     * const text = await retriever.decodeQrCodeFromBuffer(qrImage);
     * console.log(text); // "Hello, World!"
     * ```
     */
    decodeQrCodeFromBuffer(imageBuffer: Buffer): Promise<string | null>;
    /**
     * Search for relevant content and decode it from video
     *
     * This is the main retrieval method that combines semantic search
     * with frame extraction and QR decoding.
     *
     * @param query Search query text
     * @param videoPath Path to the QR video file
     * @param matchCount Number of results to return (default: 5)
     * @returns Array of search results with decoded text and similarity scores
     *
     * @example
     * ```typescript
     * const results = await retriever.search(
     *   "authentication configuration",
     *   "./docs.mp4",
     *   3
     * );
     *
     * for (const result of results) {
     *   console.log(`[${result.similarity.toFixed(2)}] ${result.text}`);
     * }
     * ```
     */
    search(query: string, videoPath: string, matchCount?: number): Promise<SearchResult[]>;
    /**
     * Search across multiple video files
     *
     * @param query Search query text
     * @param videoPaths Array of video file paths
     * @param matchCountPerVideo Number of results per video
     * @returns Aggregated and sorted results from all videos
     *
     * @example
     * ```typescript
     * const results = await retriever.searchMultiple(
     *   "API documentation",
     *   ["./docs-v1.mp4", "./docs-v2.mp4"],
     *   3
     * );
     * ```
     */
    searchMultiple(query: string, videoPaths: string[], matchCountPerVideo?: number): Promise<SearchResult[]>;
    /**
     * Retrieve a specific frame by document ID and frame number
     *
     * @param videoPath Path to the video file
     * @param documentId Document identifier
     * @param frameNumber Frame number
     * @returns Decoded text or null
     */
    getFrameByNumber(videoPath: string, frameNumber: number): Promise<string | null>;
    /**
     * Clear the frame cache
     */
    clearCache(): void;
    /**
     * Get cache statistics
     */
    getCacheStats(): {
        size: number;
        maxSize: number;
        hitRate?: number;
    };
    /**
     * Add item to cache with LRU eviction
     */
    private addToCache;
    /**
     * Batch decode multiple frames from a video
     *
     * @param videoPath Path to video file
     * @param frameNumbers Array of frame numbers to decode
     * @returns Map of frame number to decoded text
     */
    batchDecodeFrames(videoPath: string, frameNumbers: number[]): Promise<Map<number, string>>;
}
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