php convert array to multidimensional array by parent id

These recursive trees are not getting any easier, what with the 'multiple parent' requirement being added ;-/ Whatever, it still look interesting...

I am not going to document all the code here as I think i have commented it enough already.

Notes:

• converted (duplicate) the 'multiple parents' to individual entries so the 'insertNode' function was easier to understand.
• rather than use 'stdClass' i made a class called 'TreeNode' as i may want to add methods later.

Working version of the code at Viper-7.com using PHP 5.3.18

Any queries about the code then post comments and i will try an answer 'em.

<?php // https://stackoverflow.com/questions/27360813/php-convert-array-to-multidimensional-array-by-parent-id

$ar = array(
    (object) array("name" => "Test1", "otherstuff"=>array('parent is Test1'), "abh"=>""),
    (object) array("name" => "Test2", "otherstuff"=>array('parent is Test1'), "abh"=>"Test1"),
    (object) array("name" => "Test3", "otherstuff"=>array('parent is Test1'), "abh"=>"Test1"),
    (object) array("name" => "Test4", "otherstuff"=>array('parent is Test1'), "abh"=>"Test1"),
    (object) array("name" => "Test5", "otherstuff"=>array('parent is Test1'), "abh"=>"Test1"),
    (object) array("name" => "Test6", "otherstuff"=>array('parent is Test5'), "abh"=>"Test5"),
    (object) array("name" => "Test7", "otherstuff"=>array('parent is Test5'), "abh"=>"Test5"),
    (object) array("name" => "Test8", "otherstuff"=>array('parent is Test5 AND Test7'), "abh"=>array("Test5", "Test7")),
    (object) array("name" => "Test9", "otherstuff"=>array('parent is Test8'), "abh"=>"Test8"),
    (object) array("name" => "Test10", "otherstuff"=>array('parent is Test6'), "abh"=>"Test6"),
    (object) array("name" => "Test11", "otherstuff"=>array('parent is Test9'), "abh"=>"Test9"),
);


/*
 * The requirement is that for any child then the parent must be in the tree already.
 */

// Convert those parent with 'arrays of parents' into individual entries as it will make the insert
// easier to understand.

// i will also convert all the input into a 'TreeNode' class while i am doing this pass down the input. 
// i can add some methods later if i wish.

// i will also get the root of the tree while i am doing this...
$rootNode = new TreeNode(array_shift($ar));

$treeNodeList = array();
foreach($ar as $node) {
    if (is_array($node->abh)) { // generate duplicate nodes
        foreach($node->abh as $parentName) {
            $node->abh = $parentName; // make it an ordinary node
            $treeNodeList[] = new TreeNode($node);
        }
        continue;
    }
    $treeNodeList[] = new TreeNode($node);
}

// var_dump($ar, $rootNode, $treeNodeList);

// Ok, we now have a node list in the appropriate order - let us build the tree

/**
 * This is a 'multiway' tree .i.e. there can be any number of 'child' nodes
 *                                 for any parent
 * Usual rules:
 *   o The parent MUST be in the tree already.
 *   o Children are added, by searching from the root of the tree, in this version
 *
 */

// the output will be here
$theTree = array($rootNode->name => $rootNode);

foreach ($treeNodeList as $childNode) { // add it
    $inserted = insertNode($rootNode, $childNode);
    if (!$inserted) {
      var_dump('Unable to insert:', $childNode, ' in tree:', $rootNode);
      die('i am here: '. __FILE__.__LINE__);
    }
}

// show the tree
echo '<pre>';
   print_r($theTree);
echo '</pre>';

exit;
// --------- end of processing -------------

/**
 * Insert the node in the tree
 *
 * @param TreeNode $parent
 * @param TreeNode $newChild
 */
function insertNode(TreeNode &$parent, TreeNode $newChild) {
    if ($newChild->abh === $parent->name) { // add it to the current parent
        $parent->children[$newChild->name] = $newChild; // add child
        return true;
    }

    // check the children
    foreach($parent->children as $newParent) {
       if (insertNode($newParent, $newChild)) {
          return true;
       }
    }
    return false; // unable to insert child in the tree
}

// -----------------------------------------------------------------------
/**
 * treeNode: (Data and Relationships)
 *   nodeId:            'name'
 *   nodeData:          'otherstuff'
 *   nodeParentList:    'abh' - may be a list of parents.
 *                          Note: In this version of the code: All the parents
 *                                MUST be in the tree already.
 *   children:          array of treeNode - recursive structure
 */

// i will make the properties all public to make it easier to debug.

class TreeNode  {
    public $name = '';
    public $otherstuff = array();
    public $abh = '';
    public $children = array(); // list of child nodes

    public function __construct(stdClass $node)
    {
        $this->name = $node->name;
        $this->otherstuff = $node->otherstuff;
        $this->abh = $node->abh;
    }
} // class end --------------------------