<?php

/*

 * This file is part of the Symfony package.

 *

 * (c) Fabien Potencier <fabien@symfony.com>

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace Symfony\Component\Config\Definition\Builder;

/**

 * This is the entry class for building a config tree.

 *

 * @author Johannes M. Schmitt <schmittjoh@gmail.com>

 */

class TreeBuilder implements NodeParentInterface

{

    protected $tree;

    protected $root;

    protected $builder;

    /**

     * Creates the root node.

     *

     * @param string      $name     The name of the root node

     * @param string      $type     The type of the root node

     * @param NodeBuilder $builder  A custom node builder instance

     *

     * @return ArrayNodeDefinition|NodeDefinition The root node (as an ArrayNodeDefinition when the type is 'array')

     *

     * @throws \RuntimeException When the node type is not supported

     */

    public function root($name, $type = 'array', NodeBuilder $builder = null)

    {

        $builder = null === $builder ? new NodeBuilder() : $builder;

        $this->root = $builder->node($name, $type);

        $this->root->setParent($this);

        return $this->root;

    }

    /**

     * Builds the tree.

     *

     * @return NodeInterface

     */

    public function buildTree()

    {

        if (null === $this->root) {

            throw new \RuntimeException('The configuration tree has no root node.');

        }

        if (null !== $this->tree) {

            return $this->tree;

        }

        return $this->tree = $this->root->getNode(true);

    }

}