import { io, Socket } from 'socket.io-client';

/**
 * Type of handler to catch server events.
 */
type EventHandler<T> = (data: T, self: InstanceManager) => void | Promise<void>;
/**
 * Type to create object that allows program instance to communicate with the central server.
 */
declare class InstanceManager {
    private _socket;
    private _program_id;
    private _worker_id;
    /**
     * Creates `InstanceManager` instance.
     *
     * @param io Socket type from included socket.io library.
     */
    constructor(io: typeof io, server?: string);
    /**
     * Socket instance.
     */
    get socket(): Socket;
    /**
     * Program id.
     */
    get program_id(): string;
    /**
     * Worker id.
     */
    get worker_id(): string;
    /**
     * Listens for specific messages from server.
     *
     * @param event Event name.
     * @param handler Callback to handle the event.
     */
    on<T>(event: string, handler: EventHandler<T>): void;
    /**
     * Emits a message to server.
     *
     * @param event Event name.
     * @param data Event payload.
     */
    emit(event: string, data: object | null): void;
}

/**
 * Exception returned when configuration given to `InstanceManager` constructor is invalid.
 */
declare class InvalidUrlException extends Error {
    constructor(message: string);
}

export { type EventHandler, InstanceManager, InvalidUrlException };