import { AxiosResponse } from 'axios';
/**
 * Interface representing the configuration for an HTTP request.
 */
interface RequestConfig {
    /** The HTTP method to be used for the request. */
    method: 'GET' | 'POST' | 'PUT' | 'DELETE';
    /** The endpoint URL for the request. */
    endpoint: string;
    /** Optional data to be sent with the request. */
    data?: any;
    /** Optional query parameters for the request. */
    params?: any;
    /** Optional API key for authentication. */
    apiKey?: string;
}
/**
 * A singleton class for making HTTP requests with configurable options and mock mode.
 */
export declare class HTTPClient {
    private static instance;
    private baseURL;
    private apiKey;
    private client;
    private mockMode;
    private defaultMockResponse;
    private constructor();
    /**
     * Gets the singleton instance of the HTTPClient.
     * @returns The HTTPClient instance.
     */
    static getInstance(): HTTPClient;
    /**
     * Sets a custom mock response message.
     * @param mockMessage - The message to be used in the mock response.
     */
    setMockHandler(mockMessage: string): void;
    /**
     * Enables or disables mock mode.
     * @param enable - Boolean flag to enable or disable mock mode.
     */
    enableMockMode(enable: boolean): void;
    /**
     * Sets the API key for authentication.
     * @param apiKey - The API key to be used for requests.
     */
    setApiKey(apiKey: string): void;
    /**
     * Sets the base URL for all requests.
     * @param baseURL - The base URL to be used.
     */
    setBaseURL(baseURL: string): void;
    /**
     * Sends an HTTP request based on the provided configuration.
     * @param config - The request configuration.
     * @returns A promise that resolves to the axios response.
     * @throws Will throw an error if the request fails.
     */
    request(config: RequestConfig): Promise<AxiosResponse<any>>;
    /**
     * Intercepts and processes the request before it is sent.
     * @param config - The request configuration.
     * @returns The processed request configuration.
     */
    private requestInterceptor;
    /**
     * Intercepts and processes the response before it is handled.
     * @param response - The axios response object.
     * @returns The processed response.
     */
    private responseInterceptor;
    /**
     * Intercepts and processes errors that occur during the request.
     * @param error - The axios error object.
     * @returns A rejected promise with the error.
     * @throws Will throw a custom error if the server is down or unavailable.
     */
    private errorInterceptor;
}
export {};