<?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\Console\Helper;
  
  use Symfony\Component\Console\Command\Command;
  
  /**
   * HelperSet represents a set of helpers to be used with a command.
   *
   * @author Fabien Potencier <fabien@symfony.com>
   */
  class HelperSet
  {
      private $helpers;
      private $command;
  
      /**
       * Constructor.
       *
       * @param Helper[] $helpers An array of helper.
       */
      public function __construct(array $helpers = array())
      {
          $this->helpers = array();
          foreach ($helpers as $alias => $helper) {
              $this->set($helper, is_int($alias) ? null : $alias);
          }
      }
  
      /**
       * Sets a helper.
       *
       * @param HelperInterface $helper The helper instance
       * @param string          $alias  An alias
       */
      public function set(HelperInterface $helper, $alias = null)
      {
          $this->helpers[$helper->getName()] = $helper;
          if (null !== $alias) {
              $this->helpers[$alias] = $helper;
          }
  
          $helper->setHelperSet($this);
      }
  
      /**
       * Returns true if the helper if defined.
       *
       * @param string $name The helper name
       *
       * @return Boolean true if the helper is defined, false otherwise
       */
      public function has($name)
      {
          return isset($this->helpers[$name]);
      }
  
      /**
       * Gets a helper value.
       *
       * @param string $name The helper name
       *
       * @return HelperInterface The helper instance
       *
       * @throws \InvalidArgumentException if the helper is not defined
       */
      public function get($name)
      {
          if (!$this->has($name)) {
              throw new \InvalidArgumentException(sprintf('The helper "%s" is not defined.', $name));
          }
  
          return $this->helpers[$name];
      }
  
      /**
       * Sets the command associated with this helper set.
       *
       * @param Command $command A Command instance
       */
      public function setCommand(Command $command = null)
      {
          $this->command = $command;
      }
  
      /**
       * Gets the command associated with this helper set.
       *
       * @return Command A Command instance
       */
      public function getCommand()
      {
          return $this->command;
      }
  }