class LoadableState<TState> {
  final LoadingState loadingState;
  final TState? data;

  const LoadableState({required this.loadingState, required this.data});

  LoadableState<TState> loading() =>
      LoadableState<TState>(loadingState: LoadingState.loading, data: null);

  LoadableState<TState> cached(TState state) =>
      LoadableState<TState>(loadingState: LoadingState.loading, data: state);

  LoadableState<TState> done(TState state) =>
      LoadableState<TState>(loadingState: LoadingState.none, data: state);

  LoadableState<TState> error({TState? state}) =>
      LoadableState<TState>(loadingState: LoadingState.failed, data: state);

  bool isBackgroundLoading() =>
      loadingState == LoadingState.loading && data != null;

  bool hasError() =>
      loadingState == LoadingState.failed;

  bool hasStateData() =>
      data != null;

  bool errorBarVisible() =>
      hasError() && hasStateData();
}

enum LoadingState {
  loading,
  failed,
  none,
}