/// <reference types="node" />
import { Server as HTTPServer } from 'http';
export declare class WebSocketService {
    private io;
    private static instance;
    private userSockets;
    private constructor();
    static initialize(server: HTTPServer): WebSocketService;
    static getInstance(): WebSocketService;
    sendNotification(userId: number, notification: any): void;
    broadcastNotification(notification: any): void;
    sendToUser(userId: number, event: string, data: any): Promise<void>;
    updateUserNotifications(userId: number): Promise<void>;
}