/// <reference types="node" />
/// <reference types="node" />
/// <reference types="node" />
import { AxiosRequestConfig } from 'axios';
import { URLSearchParams } from 'url';
import { IncomingMessage } from 'http';
import { ProxyConfig } from './types';
type HttpMethod = 'GET' | 'DELETE' | 'POST' | 'PUT' | 'PATCH';
/**
 * Axios error codes for transient transport-level failures that should be retried.
 * Mirrors deepl-python's broader ConnectionError retry coverage.
 * @internal
 */
export declare const RETRYABLE_AXIOS_ERROR_CODES: Set<string>;
/**
 * Options for sending HTTP requests.
 * @private
 */
interface SendRequestOptions {
    /**
     * Fields to include in message body (or params) as form-encoded data. Values must be either
     * strings, or arrays of strings (for repeated parameters).
     * Cannot be used together with jsonBody.
     */
    data?: URLSearchParams;
    /**
     * JSON body to send with the request. If provided, Content-Type will be set to
     * application/json. Cannot be used together with data or fileBuffer.
     */
    jsonBody?: Record<string, unknown>;
    /** Extra HTTP headers to include in request, in addition to headers defined in constructor. */
    headers?: Record<string, string>;
    /** Buffer containing file data to include. */
    fileBuffer?: Buffer;
    /** Filename of file to include. */
    filename?: string;
}
/**
 * Internal class implementing HTTP requests.
 * @private
 */
export declare class HttpClient {
    private readonly serverUrl;
    private readonly headers;
    private readonly minTimeout;
    private readonly maxRetries;
    private readonly proxy?;
    constructor(serverUrl: string, headers: Record<string, string>, maxRetries: number, minTimeout: number, proxy?: ProxyConfig);
    prepareRequest(method: HttpMethod, url: string, timeoutMs: number, responseAsStream: boolean, options: SendRequestOptions): AxiosRequestConfig;
    /**
     * Makes API request retrying if necessary, and returns (as Promise) response.
     * @param method HTTP method, for example 'GET'
     * @param url Path to endpoint, excluding base server URL.
     * @param options Additional options controlling request.
     * @param responseAsStream Set to true if the return type is IncomingMessage.
     * @return Fulfills with status code and response (as text or stream).
     */
    sendRequestWithBackoff<TContent extends string | IncomingMessage>(method: HttpMethod, url: string, options?: SendRequestOptions, responseAsStream?: boolean): Promise<{
        statusCode: number;
        content: TContent;
    }>;
    /**
     * Performs given HTTP request and returns status code and response content (text or stream).
     * @param axiosRequestConfig
     * @private
     */
    private static sendAxiosRequest;
    private static shouldRetry;
}
export {};