/**
* Return an index of existing links.
*
* @param LinkTreeBuilder $tree
* @param GroupRepositoryInterface $groups
* @param null $group
* @return \Illuminate\Http\RedirectResponse|\Illuminate\Http\Response
*/
public function index(LinkTreeBuilder $tree, GroupRepositoryInterface $groups, $group = null)
{
if (!$group) {
$this->messages->warning('Please choose a group first.');
return $this->response->redirectTo('admin/navigation');
}
$tree->setGroup($group = $groups->findBySlug($group));
$this->breadcrumbs->add($group->getName());
return $tree->render();
}
