<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

//@require 'Swift/Events/SendListener.php';
//@require 'Swift/Events/SendEvent.php';
//@require 'Swift/Plugins/Decorator/Replacements.php';

/**
 * Allows customization of Messages on-the-fly.
 * 
 * @package Swift
 * @subpackage Plugins
 * 
 * @author Chris Corbyn
 */
class Swift_Plugins_DecoratorPlugin
  implements Swift_Events_SendListener, Swift_Plugins_Decorator_Replacements
{

  /** The replacement map */
  private $_replacements;
  
  /** The body as it was before replacements */
  private $_orginalBody;

  /** The original subject of the message, before replacements */
  private $_originalSubject;

  /** Bodies of children before they are replaced */
  private $_originalChildBodies = array();

  /** The Message that was last replaced */
  private $_lastMessage;

  /**
   * Create a new DecoratorPlugin with $replacements.
   * 
   * The $replacements can either be an associative array, or an implementation
   * of {@link Swift_Plugins_Decorator_Replacements}.
   * 
   * When using an array, it should be of the form:
   * <code>
   * $replacements = array(
   *  "address1@domain.tld" => array("{a}" => "b", "{c}" => "d"),
   *  "address2@domain.tld" => array("{a}" => "x", "{c}" => "y")
   * )
   * </code>
   * 
   * When using an instance of {@link Swift_Plugins_Decorator_Replacements},
   * the object should return just the array of replacements for the address
   * given to {@link Swift_Plugins_Decorator_Replacements::getReplacementsFor()}.
   * 
   * @param mixed $replacements
   */
  public function __construct($replacements)
  {
    if (!($replacements instanceof Swift_Plugins_Decorator_Replacements))
    {
      $this->_replacements = (array) $replacements;
    }
    else
    {
      $this->_replacements = $replacements;
    }
  }

  /**
   * Invoked immediately before the Message is sent.
   * 
   * @param Swift_Events_SendEvent $evt
   */
  public function beforeSendPerformed(Swift_Events_SendEvent $evt)
  {
    $message = $evt->getMessage();
    $this->_restoreMessage($message);
    $to = array_keys($message->getTo());
    $address = array_shift($to);
    if ($replacements = $this->getReplacementsFor($address))
    {
      $body = $message->getBody();
      $search = array_keys($replacements);
      $replace = array_values($replacements);
      $bodyReplaced = str_replace(
        $search, $replace, $body
        );
      if ($body != $bodyReplaced)
      {
        $this->_originalBody = $body;
        $message->setBody($bodyReplaced);
      }
      $subject = $message->getSubject();
      $subjectReplaced = str_replace(
        $search, $replace, $subject
        );
      if ($subject != $subjectReplaced)
      {
        $this->_originalSubject = $subject;
        $message->setSubject($subjectReplaced);
      }
      $children = (array) $message->getChildren();
      foreach ($children as $child)
      {
        list($type, ) = sscanf($child->getContentType(), '%[^/]/%s');
        if ('text' == $type)
        {
          $body = $child->getBody();
          $bodyReplaced = str_replace(
            $search, $replace, $body
            );
          if ($body != $bodyReplaced)
          {
            $child->setBody($bodyReplaced);
            $this->_originalChildBodies[$child->getId()] = $body;
          }
        }
      }
      $this->_lastMessage = $message;
    }
  }
  
  /**
   * Find a map of replacements for the address.
   * 
   * If this plugin was provided with a delegate instance of
   * {@link Swift_Plugins_Decorator_Replacements} then the call will be
   * delegated to it.  Otherwise, it will attempt to find the replacements
   * from the array provided in the constructor.
   * 
   * If no replacements can be found, an empty value (NULL) is returned.
   * 
   * @param string $address
   * 
   * @return array
   */
  public function getReplacementsFor($address)
  {
    if ($this->_replacements instanceof Swift_Plugins_Decorator_Replacements)
    {
      return $this->_replacements->getReplacementsFor($address);
    }
    else
    {
      return isset($this->_replacements[$address])
        ? $this->_replacements[$address]
        : null
        ;
    }
  }

  /**
   * Invoked immediately after the Message is sent.
   * 
   * @param Swift_Events_SendEvent $evt
   */
  public function sendPerformed(Swift_Events_SendEvent $evt)
  {
    $this->_restoreMessage($evt->getMessage());
  }

  // -- Private methods

  /** Restore a changed message back to its original state */
  private function _restoreMessage(Swift_Mime_Message $message)
  {
    if ($this->_lastMessage === $message)
    {
      if (isset($this->_originalBody))
      {
        $message->setBody($this->_originalBody);
        $this->_originalBody = null;
      }
      if (isset($this->_originalSubject))
      {
        $message->setSubject($this->_originalSubject);
        $this->_originalSubject = null;
      }
      if (!empty($this->_originalChildBodies))
      {
        $children = (array) $message->getChildren();
        foreach ($children as $child)
        {
          $id = $child->getId();
          if (array_key_exists($id, $this->_originalChildBodies))
          {
            $child->setBody($this->_originalChildBodies[$id]);
          }
        }
        $this->_originalChildBodies = array();
      }
      $this->_lastMessage = null;
    }
  }

}