import * as signalR from "@microsoft/signalr";
import * as Utility from "../Core/Utility";

export class SystemHub {

    private static _instance: SystemHub;

    public hub: signalR.HubConnection;
    private _connectionState: number;

    /**
    * Erstellt eine Instanz
    */
    private constructor() {
        this.init();
        this._connectionState = 0;
    }

    /**
     * Instanz
     */
    static getInstance(): SystemHub {
        if (!SystemHub._instance) {
            SystemHub._instance = new SystemHub();
        }
        return SystemHub._instance;
    }

    /**
     * Initialisierung des Moduls
     */
    private async init(): Promise<void> {
        var self = this;

        self.hub = new signalR.HubConnectionBuilder()
            .withUrl("/systemHub")
            .withAutomaticReconnect()
            .build();

        self.hub.onclose(async () => {
            self._connectionState = 0;
            await self.connectHub();
        });

        //self.connectHub();
    }

    /**
     * Verbindung zum Hub starten....
     */
    public async connectHub(): Promise<void> {
        var self = this;
        if (self._connectionState === 0) {
            await self.hub.start().then(() => {
                self._connectionState = 1;
            }).catch(async e => {
                await Utility.sleep(500);
                if (self._connectionState === 0)
                    await self.connectHub();
            });
        }
    }
}