Tree traversal - move subtree

MoveSubtree.php

<?php

public function moveSubtree($node, $parent)
    {
        $lft = $parent->getRgt();
        $lvl = $parent->getLvl() + 1;

        $diff = $node->getRgt() - $node->getLft() + 1;

        if ($lft > $node->getLft()) {
            $lft -= $diff;
        }

        if ($lft !== $node->getLft()) {
            $minLft = min($lft, $node->getLft());
            $maxRgt = max($lft + $diff - 1, $node->getRgt());
            $move = $lft - $node->getLft();
            if ($lft > $node->getLft()) {
                $diff = -$diff;
            }

            $nodesToModify = $this->getQueryBuilder()
                ->select('c')
                ->from(Category::class, 'c')
                ->andWhere('c.rgt >= :minLft')
                ->andWhere('c.lft <= :maxRgt')
                ->setParameter('minLft', $minLft)
                ->setParameter('maxRgt', $maxRgt)
                ->getQuery()->getResult();

            foreach ($nodesToModify as $nodeToModify) {
                if ($nodeToModify->getId() === $node->getId()) {
                    $nodeToModify->setParent($parent);
                }

                $subtree = $nodeToModify->getLft() >= $node->getLft()
                    && $nodeToModify->getRgt() <= $node->getRgt();
                $nodeLft = $subtree
                    ? $nodeToModify->getLft() + $move
                    : $nodeToModify->getLft() + ($nodeToModify->getLft() >= $minLft ? $diff : 0);
                $nodeRgt = $subtree
                    ? $nodeToModify->getRgt() + $move
                    : $nodeToModify->getRgt() + ($nodeToModify->getRgt() <= $maxRgt ? $diff : 0);
                $nodeLvl = $subtree ? $nodeToModify->getLvl() : $nodeToModify->getLvl() + $lvl - $node->getLvl();
                $nodeToModify->setTreeValues($nodeLft, $nodeRgt, $nodeLvl);
                $this->_em->persist($nodeToModify);
            }
        }
    }