Convert flat tree to tree

Input

[
    [
        'id' => 1,
        'name_lv1' => 'Parent0',
        'name_lv2' => null,
        'name_lv3' => null,
        'name_lv4' => null,
        'name_lv5' => null,
    ],
    [
        'id' => 2,
        'name_lv1' => 'Parent1',
        'name_lv2' => null,
        'name_lv3' => null,
        'name_lv4' => null,
        'name_lv5' => null,
    ],
    [
        'id' => 3,
        'name_lv1' => 'Parent1',
        'name_lv2' => 'Childen_1_1',
        'name_lv3' => null,
        'name_lv4' => null,
        'name_lv5' => null,
    ],
    [
        'id' => 4,
        'name_lv1' => 'Parent1',
        'name_lv2' => 'Childen_1_1',
        'name_lv3' => 'Childen_2_1',
        'name_lv4' => null,
        'name_lv5' => null,
    ],
    [
        'id' => 5,
        'name_lv1' => 'Parent1',
        'name_lv2' => 'Childen_1_1',
        'name_lv3' => 'Childen_2_1',
        'name_lv4' => 'Childen_3_1',
        'name_lv5' => null,
    ],
    [
        'id' => 6,
        'name_lv1' => 'Parent1',
        'name_lv2' => 'Childen_1_1',
        'name_lv3' => 'Childen_2_1',
        'name_lv4' => 'Childen_3_1',
        'name_lv5' => 'Childen_4_1',
    ],
    [
        'id' => 7,
        'name_lv1' => 'Parent1',
        'name_lv2' => 'Childen_1_1',
        'name_lv3' => 'Childen_2_1',
        'name_lv4' => 'Childen_3_1',
        'name_lv5' => 'Childen_4_2',
    ],
    [
        'id' => 8,
        'name_lv1' => 'Parent2',
        'name_lv2' => null,
        'name_lv3' => null,
        'name_lv4' => null,
        'name_lv5' => null,
    ],
    [
        'id' => 9,
        'name_lv1' => 'Parent2',
        'name_lv2' => 'Childen_1_2',
        'name_lv3' => null,
        'name_lv4' => null,
        'name_lv5' => null,
    ],
]

Output

Array
(
    [0] => Array
        (
            [id] => 1
            [name_lv1] => Parent0
            [name_lv2] => 
            [name_lv3] => 
            [name_lv4] => 
            [name_lv5] => 
        )

    [1] => Array
        (
            [id] => 2
            [name_lv1] => Parent1
            [name_lv2] => 
            [name_lv3] => 
            [name_lv4] => 
            [name_lv5] => 
            [0] => Array
                (
                    [id] => 3
                    [name_lv1] => Parent1
                    [name_lv2] => Childen_1_1
                    [name_lv3] => 
                    [name_lv4] => 
                    [name_lv5] => 
                    [0] => Array
                        (
                            [id] => 4
                            [name_lv1] => Parent1
                            [name_lv2] => Childen_1_1
                            [name_lv3] => Childen_2_1
                            [name_lv4] => 
                            [name_lv5] => 
                            [0] => Array
                                (
                                    [id] => 5
                                    [name_lv1] => Parent1
                                    [name_lv2] => Childen_1_1
                                    [name_lv3] => Childen_2_1
                                    [name_lv4] => Childen_3_1
                                    [name_lv5] => 
                                    [0] => Array
                                        (
                                            [id] => 6
                                            [name_lv1] => Parent1
                                            [name_lv2] => Childen_1_1
                                            [name_lv3] => Childen_2_1
                                            [name_lv4] => Childen_3_1
                                            [name_lv5] => Childen_4_1
                                        )

                                    [1] => Array
                                        (
                                            [id] => 7
                                            [name_lv1] => Parent1
                                            [name_lv2] => Childen_1_1
                                            [name_lv3] => Childen_2_1
                                            [name_lv4] => Childen_3_1
                                            [name_lv5] => Childen_4_2
                                        )

                                )

                        )

                )

        )

    [2] => Array
        (
            [id] => 8
            [name_lv1] => Parent2
            [name_lv2] => 
            [name_lv3] => 
            [name_lv4] => 
            [name_lv5] => 
            [0] => Array
                (
                    [id] => 9
                    [name_lv1] => Parent2
                    [name_lv2] => Childen_1_2
                    [name_lv3] => 
                    [name_lv4] => 
                    [name_lv5] => 
                )

        )

)

Tree.php

class Tree
{
    public $items;
    public $prefix;

    /**
     * Tree constructor.
     * @param $items
     * @param string $prefix
     */
    public function __construct($items, $prefix = 'name_lv')
    {
        $this->items = $items;
        $this->prefix = $prefix;
    }

    public function toBranchTree()
    {
        $treeWithLevel = $this->toTreeWithLevel();
        $reverseLevel = count($treeWithLevel) + 1;
        while (--$reverseLevel > 0) {
            if ($reverseLevel !== 1) {
                foreach ($treeWithLevel[$reverseLevel] as $currentLevel) {
                    foreach ($treeWithLevel[$reverseLevel - 1] as $index => $parentLevel) {
                        if (strpos($currentLevel['child_id'], $parentLevel['child_id']) !== false) {
                            $treeWithLevel[$reverseLevel - 1][$index][] = $currentLevel;
                        }
                    }
                }
            }
        }

        return $treeWithLevel[1];
    }

    public function toTreeWithLevel()
    {
        $treeWithLevel = [];
        foreach ($this->items as $item) {
            $level = $this->getItemLevel($item);
            $item['child_id'] = $this->getChildId($item);
            $treeWithLevel[$level][] = $item;
        }

        return $treeWithLevel;
    }

    protected function getItemLevel($item)
    {
        $level = 0;
        foreach ($item as $key => $value) {
            if (strpos($key, $this->prefix) !== false && $value != null) {
                $level++;
            }
        }

        return $level;
    }

    protected function getChildId($item)
    {
        $prefix = $this->prefix;
        return array_reduce(array_keys($item), function ($carry, $key) use ($item, $prefix) {
            if (strpos($key, $prefix) !== false) {
                $carry .= $item[$key];
            }
            return $carry;
        });
    }
}