/**
 * Base service class that provides common functionality for all API services.
 * Handles authentication, request signing, and HTTP communication with the Cryptomus API.
 * This class is extended by PaymentsService, PayoutsService, and OtherService.
 *
 * @abstract
 * @class
 */
export declare abstract class BaseService {
    protected readonly merchantId: string;
    protected readonly paymentKey: string;
    protected readonly payoutKey: string;
    protected readonly baseUrl: string;
    /**
     * Creates a new instance of the BaseService.
     *
     * @param {string} merchantId - Your Cryptomus merchant ID.
     * @param {string} paymentKey - Your API key for payment operations.
     * @param {string} payoutKey - Your API key for payout operations.
     * @param {string} baseUrl - The base URL of the Cryptomus API.
     */
    constructor(merchantId: string, paymentKey: string, payoutKey: string, baseUrl: string);
    /**
     * Generates a signature for API request authentication.
     * The signature is created by encoding the request payload to base64,
     * concatenating it with the appropriate API key, and creating an MD5 hash.
     *
     * @protected
     * @param {Record<string, any>} payload - The request payload to sign.
     * @param {boolean} [isPayment=true] - Whether to use payment key (true) or payout key (false).
     * @param {boolean} [jsonUnescape=false] - Whether to unescape JSON slashes.
     * @returns {string} The generated signature in hexadecimal format.
     *
     * @example
     * ```typescript
     * const payload = { amount: "100", currency: "USD" };
     * const signature = this.generateSign(payload, true);
     * ```
     */
    protected generateSign(payload: Record<string, any>, isPayment?: boolean, jsonUnescape?: boolean): string;
    /**
     * Makes an HTTP request to the Cryptomus API.
     * Handles request signing, error handling, and response parsing.
     *
     * @protected
     * @template T - The expected response type.
     * @param {string} endpoint - The API endpoint to call (e.g., "/payment/create").
     * @param {"GET" | "POST"} method - The HTTP method to use.
     * @param {Record<string, any>} [payload] - Optional request payload for POST requests.
     * @param {boolean} [isPayment=true] - Whether this is a payment request (true) or payout request (false).
     * @returns {Promise<T>} A promise that resolves with the API response data.
     * @throws {Error} If the request fails, returns an error response, or encounters validation errors.
     *
     * @example
     * ```typescript
     * const response = await this.request<CreatePaymentResponse>(
     *   "/payment",
     *   "POST",
     *   { amount: "100", currency: "USD" }
     * );
     * ```
     */
    protected request<T>(endpoint: string, method: "GET" | "POST", payload?: Record<string, any>, isPayment?: boolean): Promise<T>;
}