/**
 * Base Chunker
 *
 * Abstract base class for all chunker implementations.
 * Provides common functionality and interface contract.
 */
import type { Chunk, Chunker, ChunkerConfig, ChunkingStrategy } from "../../types/index.js";
/**
 * Default chunker configuration
 */
export declare const DEFAULT_CHUNKER_CONFIG: ChunkerConfig;
/**
 * Base Chunker abstract class
 *
 * All chunker implementations should extend this class.
 */
export declare abstract class BaseChunker implements Chunker {
    abstract readonly strategy: ChunkingStrategy;
    protected config: ChunkerConfig;
    constructor(config?: ChunkerConfig);
    /**
     * Get default configuration for this chunker
     */
    getDefaultConfig(): ChunkerConfig;
    /**
     * Validate chunker configuration
     */
    protected validateConfig(): void;
    /**
     * Chunk content into smaller pieces
     */
    chunk(content: string, config?: ChunkerConfig): Promise<Chunk[]>;
    /**
     * Perform the actual chunking (to be implemented by subclasses)
     */
    protected abstract doChunk(content: string, config: ChunkerConfig): Promise<Chunk[]>;
    /**
     * Filter chunks based on minimum size
     */
    protected filterChunks(chunks: Chunk[], config: ChunkerConfig): Chunk[];
    /**
     * Create a chunk object
     */
    protected createChunk(text: string, chunkIndex: number, startPosition: number, endPosition: number, documentId?: string, customMetadata?: Record<string, unknown>): Chunk;
    /**
     * Split content by size with overlap
     */
    protected splitBySizeWithOverlap(content: string, maxSize: number, overlap: number): Array<{
        text: string;
        start: number;
        end: number;
    }>;
}