import type { AnySyncMiddleware, ErrorMiddleware, Middleware, MiddlewareResult, OptionsResponse, SpecialNextParam } from './shared.js';
/**
 * MiddlewareIndexed class that implements Middleware.
 * @template T
 * @template TMiddleware
 * @template TSpecialNextParam
 */
export declare class MiddlewareIndexed<T extends unknown[], TMiddleware extends AnySyncMiddleware<T, TSpecialNextParam>, TSpecialNextParam extends string | undefined = SpecialNextParam> implements Middleware<T, TSpecialNextParam> {
    private getIndexKey;
    readonly name?: string;
    protected _delegate: Middleware<T, TSpecialNextParam>;
    /**
     * Constructor for MiddlewareIndexed.
     * @param {function} getIndexKey - Function to get the index key.
     * @param {string} [name] - Optional name for the middleware.
     */
    constructor(getIndexKey: (...args: T) => string, name?: string);
    /**
     * Get the keys from the index.
     * @returns {string[]} Array of keys.
     */
    protected getKeys(): string[];
    protected readonly index: Record<string, TMiddleware> & {
        ''?: ErrorMiddleware<T, TSpecialNextParam>;
    };
    /**
     * Use middleware for a specific key.
     * @param {string|null} key - The key for the middleware.
     * @param {AnySyncMiddleware} middleware - The middleware to use.
     * @returns {this} The current instance.
     */
    useMiddleware(key: null, middleware: Middleware<T, TSpecialNextParam>): this;
    useMiddleware(key: '', middleware: ErrorMiddleware<T, TSpecialNextParam>): this;
    useMiddleware(key: string, middleware: TMiddleware): this;
    /**
     * Use an error handler.
     * @param {function} handler - The error handler function.
     * @returns {this} The current instance.
     */
    useError(handler: ((error: Error | OptionsResponse, ...args: T) => unknown)): this;
    /**
     * Process the request.
     * @template X
     * @param {...T} req - The request parameters.
     * @returns {X} The result of the process.
     */
    process<X = unknown>(...req: T): X;
    /**
     * Handle an error.
     * @param {Error|OptionsResponse} error - The error to handle.
     * @param {...T} req - The request parameters.
     * @returns {MiddlewareResult<TSpecialNextParam>} The result of the error handling.
     */
    handleError(error: Error | OptionsResponse, ...req: T): MiddlewareResult<TSpecialNextParam>;
    /**
     * Handle the request.
     * @param {...T} req - The request parameters.
     * @returns {MiddlewareResult<TSpecialNextParam>} The result of the handling.
     */
    handle(...req: T): MiddlewareResult<TSpecialNextParam>;
}