/** Module containing RecursiveChunker class. */
import { Tokenizer } from "../tokenizer";
import { RecursiveChunk, RecursiveRules } from "../types/recursive";
import { BaseChunker } from "./base";
/**
 * Configuration options for creating a RecursiveChunker instance.
 * All options are optional and have sensible defaults.
 *
 * @interface RecursiveChunkerOptions
 * @property {string | Tokenizer} [tokenizer] - The tokenizer to use for text processing. Can be a string identifier (default: "Xenova/gpt2") or a Tokenizer instance.
 * @property {number} [chunkSize] - The maximum number of tokens per chunk. Must be greater than 0. Default: 512.
 * @property {RecursiveRules} [rules] - The rules that define how text should be recursively chunked. Default: new RecursiveRules().
 * @property {number} [minCharactersPerChunk] - The minimum number of characters that should be in each chunk. Must be greater than 0. Default: 24.
 */
export interface RecursiveChunkerOptions {
    tokenizer?: string | Tokenizer;
    chunkSize?: number;
    rules?: RecursiveRules;
    minCharactersPerChunk?: number;
}
/**
 * Configuration options for creating a RecursiveChunker instance from a recipe.
 * All options are optional and have sensible defaults.
 *
 * @interface RecursiveChunkerRecipeOptions
 * @property {string} [name] - The name of the recipe to get. Default: 'default'.
 * @property {string} [language] - The language of the recipe to get. Default: 'en'.
 * @property {string} [filePath] - Optionally, provide the path to the recipe file.
 * @property {string | Tokenizer} [tokenizer] - The tokenizer to use for text processing. Can be a string identifier (default: "Xenova/gpt2") or a Tokenizer instance.
 * @property {number} [chunkSize] - The maximum number of tokens per chunk. Must be greater than 0. Default: 512.
 * @property {number} [minCharactersPerChunk] - The minimum number of characters that should be in each chunk. Must be greater than 0. Default: 24.
 */
export interface RecursiveChunkerRecipeOptions {
    name?: string;
    language?: string;
    filePath?: string;
    tokenizer?: string | Tokenizer;
    chunkSize?: number;
    minCharactersPerChunk?: number;
}
/**
 * Represents a RecursiveChunker instance that is also directly callable as a function.
 *
 * This type combines all properties and methods of {@link RecursiveChunker} with callable signatures for chunking text(s).
 *
 * Calling the instance executes its `call` method (from {@link BaseChunker}), which in turn calls `chunk` or `chunkBatch`.
 *
 * @typedef {Object} CallableRecursiveChunker
 * @property {number} chunkSize - The maximum number of tokens per chunk.
 * @property {number} minCharactersPerChunk - The minimum number of characters per chunk.
 * @property {RecursiveRules} rules - The rules that define how text should be recursively chunked.
 * @property {string} sep - The separator string used for internal splitting (usually "✄").
 * @property {Tokenizer} tokenizer - The tokenizer instance used for chunking operations (inherited from BaseChunker).
 *
 * @method chunk - Recursively chunk a single text into chunks or strings.
 * @method chunkBatch - Recursively chunk a batch of texts.
 * @method toString - Returns a string representation of the RecursiveChunker instance.
 * @method call - Call the chunker with a single string or an array of strings. (see callable signatures)
 *
 * @static
 * @method create
 * @memberof CallableRecursiveChunker
 * @param {RecursiveChunkerOptions} [options] - Configuration options for the RecursiveChunker.
 * @returns {Promise<CallableRecursiveChunker>} A Promise that resolves to a callable RecursiveChunker instance.
 *
 * @example
 * const chunker = await RecursiveChunker.create({ chunkSize: 256 });
 * const chunks = await chunker("Some text to chunk");
 * const batchChunks = await chunker(["Text 1", "Text 2"]);
 */
export type CallableRecursiveChunker = RecursiveChunker & {
    (text: string, showProgress?: boolean): Promise<RecursiveChunk[]>;
    (texts: string[], showProgress?: boolean): Promise<(RecursiveChunk[])[]>;
};
/**
 * Recursively chunk text using a set of rules.
 *
 * This class extends the BaseChunker class and implements the chunk method.
 * It provides a flexible way to chunk text based on custom rules, including
 * delimiters, whitespace, and token-based chunking.
 *
 * @extends BaseChunker
 * @property {number} chunkSize - The maximum number of tokens per chunk.
 * @property {number} minCharactersPerChunk - The minimum number of characters per chunk.
 * @property {RecursiveRules} rules - The rules that define how text should be recursively chunked.
 * @property {string} sep - The separator string used for internal splitting (usually "✄").
 *
 * @method chunk - Recursively chunk a single text into chunks or strings.
 * @method chunkBatch - Recursively chunk a batch of texts.
 * @method toString - Returns a string representation of the RecursiveChunker instance.
 * @method call - Call the chunker with a single string or an array of strings. (see callable signatures)
 *
 * @static
 * @method create
 * @memberof RecursiveChunker
 * @param {RecursiveChunkerOptions} [options] - Configuration options for the RecursiveChunker.
 * @returns {Promise<RecursiveChunker>} A Promise that resolves to a RecursiveChunker instance.
 *
 * @example
 * const chunker = await RecursiveChunker.create({ chunkSize: 256 });
 * const chunks = await chunker("Some text to chunk");
 * const batchChunks = await chunker(["Text 1", "Text 2"]);
 */
export declare class RecursiveChunker extends BaseChunker {
    readonly chunkSize: number;
    readonly minCharactersPerChunk: number;
    readonly rules: RecursiveRules;
    readonly sep: string;
    private readonly _CHARS_PER_TOKEN;
    /**
     * Private constructor. Use `RecursiveChunker.create()` to instantiate.
     */
    private constructor();
    /**
     * Creates and initializes a directly callable RecursiveChunker instance.
     *
     * This static factory method constructs a RecursiveChunker with the provided options and returns a callable function object.
     * The returned instance can be used as both a function (to chunk text(s)) and as an object (with all RecursiveChunker methods and properties).
     *
     * @param {RecursiveChunkerOptions} [options] - Configuration options for the chunker. All options are optional:
     *   @param {string|Tokenizer} [options.tokenizer="Xenova/gpt2"] - Tokenizer to use for text processing. Can be a string identifier (e.g., "Xenova/gpt2") or a Tokenizer instance. If a string is provided, Tokenizer.create() is called internally.
     *   @param {number} [options.chunkSize=512] - Maximum number of tokens per chunk. Must be > 0.
     *   @param {RecursiveRules} [options.rules=new RecursiveRules()] - Rules for recursive chunking. See {@link RecursiveRules} for customization.
     *   @param {number} [options.minCharactersPerChunk=24] - Minimum number of characters per chunk. Must be > 0.
     *
     * @returns {Promise<CallableRecursiveChunker>} Promise resolving to a callable RecursiveChunker instance.
     *
     * @throws {Error} If any option is invalid (e.g., chunkSize <= 0).
     *
     * @see CallableRecursiveChunker for the callable interface and available properties/methods.
     *
     * @example <caption>Basic usage with default options</caption>
     * const chunker = await RecursiveChunker.create();
     * const chunks = await chunker("Some text to chunk");
     *
     * @example <caption>Custom options and batch chunking</caption>
     * const chunker = await RecursiveChunker.create({ chunkSize: 256 });
     * const batchChunks = await chunker(["Text 1", "Text 2"]);
     *
     * @example <caption>Accessing properties and methods</caption>
     * const chunker = await RecursiveChunker.create();
     * console.log(chunker.chunkSize); // 512
     * console.log(chunker.rules); // RecursiveRules instance
     * const chunks = await chunker.chunk("Some text"); // Use as object method
     *
     * @note
     * The returned instance is both callable (like a function) and has all properties/methods of RecursiveChunker.
     * You can use it as a drop-in replacement for a function or a class instance.
     *
     * @note
     * For advanced customization, pass a custom RecursiveRules object to the rules option.
     * See {@link RecursiveRules} and {@link RecursiveLevel} for rule structure.
     */
    static create(options?: RecursiveChunkerOptions): Promise<CallableRecursiveChunker>;
    /**
     * Creates and initializes a RecursiveChunker instance from a recipe that is directly callable.
     *
     * This method loads a recipe from the Chonkie hub and uses the recipe's recursive rules
     * to configure the RecursiveChunker. The recipe rules override the default rules.
     *
     * @param {RecursiveChunkerRecipeOptions} [options] - Options for configuring the RecursiveChunker with recipe settings.
     * @returns {Promise<CallableRecursiveChunker>} A promise that resolves to a callable RecursiveChunker instance.
     *
     * @example
     * const chunker = await RecursiveChunker.fromRecipe({ name: 'default', language: 'en' });
     * const chunks = await chunker("This is a sample text.");
     *
     * @see RecursiveChunkerRecipeOptions
     */
    static fromRecipe(options?: RecursiveChunkerRecipeOptions): Promise<CallableRecursiveChunker>;
    /**
     * Estimates the number of tokens in a given text.
     *
     * This method uses a character-to-token ratio (default: 6.5 characters per token) for quick estimation.
     * If the estimated token count exceeds the chunk size, it performs an actual token count.
     *
     * @param {string} text - The text to estimate token count for
     * @returns {Promise<number>} A promise that resolves to the estimated number of tokens
     * @private
     */
    private _estimateTokenCount;
    /**
     * Split the text into chunks based on the provided recursive level rules.
     *
     * This method handles three different splitting strategies:
     * 1. Whitespace-based splitting: Splits text on spaces
     * 2. Delimiter-based splitting: Splits text on specified delimiters with options to include delimiters
     * 3. Token-based splitting: Splits text into chunks of maximum token size
     *
     * @param {string} text - The text to be split into chunks
     * @param {RecursiveLevel} recursiveLevel - The rules defining how to split the text
     * @returns {Promise<string[]>} A promise that resolves to an array of text chunks
     * @private
     */
    private _splitText;
    /**
     * Create a RecursiveChunk object with indices based on the current offset.
     *
     * This method constructs a RecursiveChunk object that contains metadata about the chunk,
     * including the text content, its start and end indices, token count, and the level of recursion.
     *
     * @param {string} text - The text content of the chunk
     * @param {number} tokenCount - The number of tokens in the chunk
     */
    private _makeChunks;
    /**
     * Merge short splits.
     */
    private _mergeSplits;
    /**
     * Binary search to find the leftmost position where value should be inserted to maintain order.
     *
     * @param {number[]} arr - The array to search
     * @param {number} value - The value to insert
     * @param {number} [lo=0] - The starting index for the search
     * @returns {number} The index where the value should be inserted
     * @private
     */
    private _bisectLeft;
    /**
     * Recursive helper for core chunking.
     */
    private _recursiveChunk;
    /**
     * Recursively chunk text.
     *
     * This method is the main entry point for chunking text using the RecursiveChunker.
     * It takes a single text string and returns an array of RecursiveChunk objects.
     *
     * @param {string} text - The text to be chunked
     * @returns {Promise<RecursiveChunk[]>} A promise that resolves to an array of RecursiveChunk objects
     */
    chunk(text: string): Promise<RecursiveChunk[]>;
    /**
     * Return a string representation of the RecursiveChunker.
     *
     * This method provides a string representation of the RecursiveChunker instance,
     * including its tokenizer, rules, chunk size, minimum characters per chunk, and return type.
     *
     * @returns {string} A string representation of the RecursiveChunker
     */
    toString(): string;
}