<?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\Command;
  
  use Symfony\Component\Console\Helper\DescriptorHelper;
  use Symfony\Component\Console\Input\InputArgument;
  use Symfony\Component\Console\Input\InputOption;
  use Symfony\Component\Console\Input\InputInterface;
  use Symfony\Component\Console\Output\OutputInterface;
  
  /**
   * HelpCommand displays the help for a given command.
   *
   * @author Fabien Potencier <fabien@symfony.com>
   */
  class HelpCommand extends Command
  {
      private $command;
  
      /**
       * {@inheritdoc}
       */
      protected function configure()
      {
          $this->ignoreValidationErrors();
  
          $this
              ->setName('help')
              ->setDefinition(array(
                  new InputArgument('command_name', InputArgument::OPTIONAL, 'The command name', 'help'),
                  new InputOption('xml', null, InputOption::VALUE_NONE, 'To output help as XML'),
                  new InputOption('format', null, InputOption::VALUE_REQUIRED, 'To output help in other formats'),
                  new InputOption('raw', null, InputOption::VALUE_NONE, 'To output raw command help'),
              ))
              ->setDescription('Displays help for a command')
              ->setHelp(<<<EOF
  The <info>%command.name%</info> command displays help for a given command:
  
    <info>php %command.full_name% list</info>
  
  You can also output the help in other formats by using the <comment>--format</comment> option:
  
    <info>php %command.full_name% --format=xml list</info>
  
  To display the list of available commands, please use the <info>list</info> command.
  EOF
              )
          ;
      }
  
      /**
       * Sets the command
       *
       * @param Command $command The command to set
       */
      public function setCommand(Command $command)
      {
          $this->command = $command;
      }
  
      /**
       * {@inheritdoc}
       */
      protected function execute(InputInterface $input, OutputInterface $output)
      {
          if (null === $this->command) {
              $this->command = $this->getApplication()->find($input->getArgument('command_name'));
          }
  
          if ($input->getOption('xml')) {
              $input->setOption('format', 'xml');
          }
  
          $helper = new DescriptorHelper();
          $helper->describe($output, $this->command, $input->getOption('format'), $input->getOption('raw'));
          $this->command = null;
      }
  }