import { BehaviorSubject } from "rxjs";

export class OsDiagnosticService {
    private static instance: OsDiagnosticService;

    public static getInstance(): OsDiagnosticService {
        if (!OsDiagnosticService.instance) {
            OsDiagnosticService.instance = new OsDiagnosticService();
        }
        return OsDiagnosticService.instance;
    }

    private _isOnline$ = new BehaviorSubject(navigator.onLine);

    private constructor() {
        window.addEventListener("online", () => this._isOnline$.next(true));
        window.addEventListener("offline", () => this._isOnline$.next(false));
    }

    public get isOnline() {
        return this._isOnline$.value;
    }
    public get isOffline() {
        return !this._isOnline$.value;
    }
    public get isOnline$() {
        return this._isOnline$.asObservable();
    }
}