Text tree renderer form Symfony forms

FormTextTreeRenderer.php

<?php

use Symfony\Component\Form\FormInterface;

class FormTextTreeRenderer
{
    public function render(FormInterface $form)
    {
        $lines[] = '.';
        $lines[] = $this->renderNode($form);
        $lines[] = '';

        return implode(PHP_EOL, $lines);
    }

    private function renderNode(FormInterface $form)
    {
        $lines[] = sprintf(
            '%s%s (%s)',
            $this->renderNodePad($form),
            $form->getName(),
            $form->getConfig()->getType()->getName()
        );

        foreach ($form->all() as $child) {
            $lines[] = $this->renderNode($child);
        }

        return implode(PHP_EOL, $lines);
    }

    private function renderNodePad(FormInterface $form)
    {
        $parts = [];

        do {
            $parent = $form->getParent();

            if (is_null($parent) || end($parent->all()) === $form) {
                $parts[] = count($parts) ? '    ' : '└── ';
            } else {
                $parts[] = count($parts) ? '|   ' : '├── ';
            }
        } while ($form = $parent);

        return implode('', array_reverse($parts));
    }
}