export function windowFactory(browserWindowRef: BrowserWindowRef, platformId: Object): Window | Object {
  if (isPlatformBrowser(platformId)) {
    return browserWindowRef.nativeWindow;
  }

  return new Object();
}

export function appInitializerFactory(counterConfigs: YandexCounterConfig[], platformId: any) {
  if (isPlatformBrowser(platformId)) {
    return insertMetrika.bind(null, counterConfigs);
  }

  return () => 'none';
}

export function documentFactory(documentRef: GlobalRef, platformId: Object): Window | Object {
  if (isPlatformBrowser(platformId)) {
    return documentRef.nativeDocument;
  }

  return {};
}

export function windowFactory(windowRef: GlobalRef, platformId: Object): Window | Object {
  if (isPlatformBrowser(platformId)) {
    return windowRef.nativeWindow;
  }

  return {};
}

export function localStorageFactory(platformId: Object): Storage {
  if (isPlatformBrowser(platformId)) {
    return localStorage;
  } else {
    return {
      length: 0,
      clear: () => {},
      getItem: () => null,
      key: () => null,
      removeItem: () => {},
      setItem: () => {}
    };
  }
}

  const initializer = () => {
    if (!(isPlatformBrowser(platformId) && ('serviceWorker' in navigator) &&
          options.enabled !== false)) {
      return;
    }

    // Wait for service worker controller changes, and fire an INITIALIZE action when a new SW
    // becomes active. This allows the SW to initialize itself even if there is no application
    // traffic.
    navigator.serviceWorker.addEventListener('controllerchange', () => {
      if (navigator.serviceWorker.controller !== null) {
        navigator.serviceWorker.controller.postMessage({action: 'INITIALIZE'});
      }
    });

    let readyToRegister$: Observable<unknown>;

    if (typeof options.registrationStrategy === 'function') {
      readyToRegister$ = options.registrationStrategy();
    } else {
      const [strategy, ...args] = (options.registrationStrategy || 'registerWhenStable').split(':');
      switch (strategy) {
        case 'registerImmediately':
          readyToRegister$ = of (null);
          break;
        case 'registerWithDelay':
          readyToRegister$ = of (null).pipe(delay(+args[0] || 0));
          break;
        case 'registerWhenStable':
          const appRef = injector.get<ApplicationRef>(ApplicationRef);
          readyToRegister$ = appRef.isStable.pipe(filter(stable => stable));
          break;
        default:
          // Unknown strategy.
          throw new Error(
              `Unknown ServiceWorker registration strategy: ${options.registrationStrategy}`);
      }
    }

    // Don't return anything to avoid blocking the application until the SW is registered or
    // causing a crash if the SW registration fails.
    readyToRegister$.pipe(take(1)).subscribe(
        () => navigator.serviceWorker.register(script, {scope: options.scope}));
  };

  const initializer = () => {
    const app = injector.get<ApplicationRef>(ApplicationRef);
    if (!(isPlatformBrowser(platformId) && ('serviceWorker' in navigator) &&
          options.enabled !== false)) {
      return;
    }
    const whenStable =
        app.isStable.pipe(filter((stable: boolean) => !!stable), take(1)).toPromise();

    // Wait for service worker controller changes, and fire an INITIALIZE action when a new SW
    // becomes active. This allows the SW to initialize itself even if there is no application
    // traffic.
    navigator.serviceWorker.addEventListener('controllerchange', () => {
      if (navigator.serviceWorker.controller !== null) {
        navigator.serviceWorker.controller.postMessage({action: 'INITIALIZE'});
      }
    });

    // Don't return the Promise, as that will block the application until the SW is registered, and
    // cause a crash if the SW registration fails.
    whenStable.then(() => navigator.serviceWorker.register(script, {scope: options.scope}));
  };

export function ngswCommChannelFactory(
    opts: RegistrationOptions, platformId: string): NgswCommChannel {
  return new NgswCommChannel(
      isPlatformBrowser(platformId) && opts.enabled !== false ? navigator.serviceWorker :
                                                                undefined);
}