import type { Express, Request, Response } from 'express';
import { z } from 'zod';
import type { API, ZodBase } from '../def';
/**
 * Arguments passed to an Express handler for an API endpoint.
 */
export interface HandlerArgs<DTO extends ZodBase | void> {
    /** The Express request object. */
    request: Request;
    /** The Express response object. */
    response: Response;
    /** The parsed and validated Data Transfer Object (DTO) from the request body. */
    dto: DTO extends ZodBase ? z.output<DTO> : void;
}
/**
 * The expected result from an API handler, which is a Promise resolving to the Value Object (VO) or void.
 */
export type HandlerResult<VO extends ZodBase | void> = VO extends ZodBase ? Promise<z.output<VO>> : Promise<void>;
/**
 * A handler function that implements the logic for an API endpoint.
 * @param args The handler arguments, including request, response, and DTO.
 * @returns A Promise that resolves with the response data (VO) or void.
 */
export interface Handler<DTO extends ZodBase | void, VO extends ZodBase | void> {
    (args: HandlerArgs<DTO>): HandlerResult<VO>;
}
/**
 * Implements a type-safe API endpoint on an Express instance.
 * @param express The Express application instance.
 * @param api The API definition created by `defineAPI`.
 * @param handler The handler function that implements the API logic.
 * @param onError An optional callback for handling errors.
 */
export declare function implApi<DTO extends ZodBase | undefined, VO extends ZodBase | undefined>(express: Express, api: API<DTO, VO>, handler: Handler<DTO extends ZodBase ? DTO : void, VO extends ZodBase ? VO : void>, onError?: (err: Error) => void): void;
/**
 * Implements a type-safe API endpoint on an Express instance using a configuration object.
 * @param impl An object containing the Express instance, API definition, handler, and optional error callback.
 */
export declare function implApi<DTO extends ZodBase | undefined, VO extends ZodBase | undefined>(impl: {
    express: Express;
    api: API<DTO, VO>;
    handler: Handler<DTO extends ZodBase ? DTO : void, VO extends ZodBase ? VO : void>;
    onError?: (err: Error) => void;
}): void;
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