<?php
/**
* This file is part of the ramsey/uuid library
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*
* @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
* @license http://opensource.org/licenses/MIT MIT
* @link https://benramsey.com/projects/ramsey-uuid/ Documentation
* @link https://packagist.org/packages/ramsey/uuid Packagist
* @link https://github.com/ramsey/uuid GitHub
*/

namespace Ramsey\Uuid\Provider\Node;

use Ramsey\Uuid\Provider\NodeProviderInterface;

/**
* FallbackNodeProvider attempts to gain the system host ID from an array of
* providers, falling back to the next in line in the event a host ID can not be
* obtained
*/
class FallbackNodeProvider implements NodeProviderInterface
{
/**
* @var NodeProviderInterface[]
*/
private $nodeProviders;

/**
* Constructs a `FallbackNodeProvider` using an array of node providers
*
* @param NodeProviderInterface[] $providers Array of node providers
*/
public function __construct(array $providers)
{
$this->nodeProviders = $providers;
}

/**
* Returns the system node ID by iterating over an array of node providers
* and returning the first non-empty value found
*
* @return string System node ID as a hexadecimal string
* @throws \Exception
*/
public function getNode()
{
foreach ($this->nodeProviders as $provider) {
if ($node = $provider->getNode()) {
return $node;
}
}

return null;
}
}