<?php

namespace Symfony\Components\RequestHandler;

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien.potencier@symfony-project.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * HeaderBag is a ParameterBag optimized to hold header HTTP headers.
 *
 * @package    Symfony
 * @subpackage Components_RequestHandler
 * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
 */
class HeaderBag extends ParameterBag
{
  protected $cacheControl;
  protected $type;

  /**
   * Replaces the current HTTP headers by a new set.
   *
   * @param array  $parameters An array of HTTP headers
   * @param string $type       The type (null, request, or response)
   */
  public function replace(array $parameters = array(), $type = null)
  {
    $this->cacheControl = null;
    $this->parameters = array();
    foreach ($parameters as $key => $value)
    {
      $this->parameters[strtr(strtolower($key), '_', '-')] = $value;
    }

    if (null !== $type && !in_array($type, array('request', 'response')))
    {
      throw new \InvalidArgumentException(sprintf('The "%s" type is not supported by the HeaderBag constructor.', $type));
    }
    $this->type = $type;
  }

  /**
   * Returns a header value by name.
   *
   * @param string $key     The key
   * @param mixed  $default The default value
   */
  public function get($key, $default = null)
  {
    $key = strtr(strtolower($key), '_', '-');

    return array_key_exists($key, $this->parameters) ? $this->parameters[$key] : $default;
  }

  /**
   * Sets a header by name.
   *
   * @param string  $key     The key
   * @param mixed   $value   The value
   * @param Boolean $replace Whether to replace the actual value of not (true by default)
   */
  public function set($key, $value, $replace = true)
  {
    $key = strtr(strtolower($key), '_', '-');

    if (false === $replace)
    {
      $current = $this->get($key, '');
      $value = ($current ? $current.', ' : '').$value;
    }

    $this->parameters[$key] = $value;

    if ('cache-control' == $key)
    {
      $this->cacheControl = null;
    }
  }

  /**
   * Returns true if the HTTP header is defined.
   *
   * @param string $key The HTTP header
   *
   * @return Boolean true if the parameter exists, false otherwise
   */
  public function has($key)
  {
    return array_key_exists(strtr(strtolower($key), '_', '-'), $this->parameters);
  }

  /**
   * Deletes a header.
   *
   * @param string $key The HTTP header name
   */
  public function delete($key)
  {
    unset($this->parameters[strtr(strtolower($key), '_', '-')]);
  }

  /**
   * Returns an instance able to manage the Cache-Control header.
   *
   * @return Symfony\Components\RequestHandler\Cache\CacheControl A CacheControl instance
   */
  public function getCacheControl()
  {
    if (null === $this->cacheControl)
    {
      $this->cacheControl = new CacheControl($this, $this->get('Cache-Control'), $this->type);
    }

    return $this->cacheControl;
  }

  /**
   * Normalizes a HTTP header name.
   *
   * @param  string $key The HTTP header name
   *
   * @return string The normalized HTTP header name
   */
  static public function normalizeHeaderName($key)
  {
    return strtr(strtolower($key), '_', '-');
  }
}