abstract class BaseBottomNavActivity extends BaseActivity { // you can directly extend AppCompatActivity

    @Override
    @CallSuper
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initOnCreate(savedInstanceState);
        getBottomNavigationBar().setOnTabSelectionListener(
                new CustomBottomNavigationBar.OnTabSelectionListener() {
                    @Override
                    public void onTabSelected(int position) { // start your various top-level activites from here
                        if (position != getCurrentBottomNavPosition()) {
                            switch (position) {
                                case CustomBottomNavigationBar.POSITION_HOME_TAB:
                                    HomeActivity.start(BaseBottomNavActivity.this);
                                    break;
                                case CustomBottomNavigationBar.POSITION_UPDATES_TAB:
                                    UpdatesActivity.start(BaseBottomNavActivity.this);
                                    break;
                                case CustomBottomNavigationBar.POSITION_BOOKMARKS_TAB:
                                    BookmarksActivity.start(BaseBottomNavActivity.this);
                                    break;
                                case CustomBottomNavigationBar.POSITION_PROFILE_TAB:
                                    ProfileActivity.start(BaseBottomNavActivity.this);
                                    break;
                                case CustomBottomNavigationBar.POSITION_FINISHED_STORIES_TAB:
                                    FinishedStoriesActivity.start(BaseBottomNavActivity.this);
                                    break;
                            }
                        } else {
                            onNavBarReselect();
                        }
                    }
                });
    }

    protected abstract void onNavBarReselect(); // child activity should implement how re-selecting the same (current) tab will be handled.

    @Override
    protected void onResume() {
        super.onResume();
        getBottomNavigationBar().setSelectedTab(getCurrentBottomNavPosition());
    }

//    TODO: uncomment if backstack behavior needs to change
//    @Override
//    public void onBackPressed() {
//        ActivityManager activityManager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
//        List<ActivityManager.AppTask> appTasks = activityManager.getAppTasks();
//        for (ActivityManager.AppTask task : appTasks) {
//            task.finishAndRemoveTask();
//        }
//    }

    protected abstract int getCurrentBottomNavPosition(); // e.g. for the switch case above HomeActivity returns CustomBottomNavigationBar.POSITION_HOME_TAB here

    protected abstract CustomBottomNavigationBar getBottomNavigationBar(); //e.g. get the bottom nav bar from the child's layout

    protected abstract void initOnCreate(Bundle savedInstanceState); //e.g. child activities to call this, initialize layout in this so that bottom nav bar is available when line 8 is called

    @NonNull
    protected Snackbar showSnackbar(Snackbar snackbar, boolean hasAction) { // used to show the snackbar above the bottom nav bar. This assumes that the parent of each child activity is a coordinator layout.
        Typeface font = Typeface.createFromAsset(getAssets(), AppTextView.APP_TEXT_FONT);
        TextView tv = (TextView) (snackbar.getView()).findViewById(android.support.design.R.id.snackbar_text);
        tv.setTypeface(font);
        Button button = (Button) (snackbar.getView()).findViewById(android.support.design.R.id.snackbar_action);
        button.setTypeface(font);
        CoordinatorLayout.LayoutParams params
                = (CoordinatorLayout.LayoutParams) snackbar.getView().getLayoutParams();
        params.setMargins(params.leftMargin, params.topMargin, params.rightMargin,
                getBottomNavigationBar().getBottomBarHeight());
        snackbar.getView().setLayoutParams(params);
        snackbar.show();
        return snackbar;
    }
}