<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Feed
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Abstract.php 8064 2008-02-16 10:58:39Z thomas $
 */

/**
 * @see Zend_Feed_Element
 */
require_once 'external/Zend/Feed/Element.php';

/**
 * The Zend_Feed_Abstract class is an abstract class representing feeds.
 *
 * Zend_Feed_Abstract implements two core PHP 5 interfaces: ArrayAccess and
 * Iterator. In both cases the collection being treated as an array is
 * considered to be the entry collection, such that iterating over the
 * feed takes you through each of the feed.s entries.
 *
 * @category   Zend
 * @package    Zend_Feed
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Feed_Abstract extends Zend_Feed_Element implements Iterator {
  /**
   * Current index on the collection of feed entries for the
   * Iterator implementation.
   *
   * @var integer
   */
  protected $_entryIndex = 0;
  
  /**
   * Cache of feed entries.
   *
   * @var array
   */
  protected $_entries;

  /**
   * Feed constructor
   *
   * The Zend_Feed_Abstract constructor takes the URI of a feed or a
   * feed represented as a string and loads it as XML.
   *
   * @param  string $uri The full URI of the feed to load, or NULL if not retrieved via HTTP or as an array.
   * @param  string $string The feed as a string, or NULL if retrieved via HTTP or as an array.
   * @param  Zend_Feed_Builder_Interface $builder The feed as a builder instance or NULL if retrieved as a string or via HTTP.
   * @return void
   * @throws Zend_Feed_Exception If loading the feed failed.
   */
  public function __construct($uri = null, $string = null, Zend_Feed_Builder_Interface $builder = null) {
    if ($uri !== null) {
      // Retrieve the feed via HTTP
      $client = Zend_Feed::getHttpClient();
      $client->setUri($uri);
      $response = $client->request('GET');
      if ($response->getStatus() !== 200) {
        /** 
         * @see Zend_Feed_Exception
         */
        require_once 'external/Zend/Feed/Exception.php';
        throw new Zend_Feed_Exception('Feed failed to load, got response code ' . $response->getStatus());
      }
      $this->_element = $response->getBody();
      $this->__wakeup();
    } elseif ($string !== null) {
      // Retrieve the feed from $string
      $this->_element = $string;
      $this->__wakeup();
    } else {
      // Generate the feed from the array
      $header = $builder->getHeader();
      $this->_element = new DOMDocument('1.0', $header['charset']);
      $root = $this->_mapFeedHeaders($header);
      $this->_mapFeedEntries($root, $builder->getEntries());
      $this->_element = $root;
      $this->_buildEntryCache();
    }
  }

  /**
   * Load the feed as an XML DOMDocument object
   *
   * @return void
   * @throws Zend_Feed_Exception
   */
  public function __wakeup() {
    @ini_set('track_errors', 1);
    $doc = @DOMDocument::loadXML($this->_element);
    @ini_restore('track_errors');
    
    if (! $doc) {
      // prevent the class to generate an undefined variable notice (ZF-2590)
      if (! isset($php_errormsg)) {
        if (function_exists('xdebug_is_enabled')) {
          $php_errormsg = '(error message not available, when XDebug is running)';
        } else {
          $php_errormsg = '(error message not available)';
        }
      }
      
      /** 
       * @see Zend_Feed_Exception
       */
      require_once 'external/Zend/Feed/Exception.php';
      throw new Zend_Feed_Exception("DOMDocument cannot parse XML: $php_errormsg");
    }
    
    $this->_element = $doc;
  }

  /**
   * Prepare for serialiation
   *
   * @return array
   */
  public function __sleep() {
    $this->_element = $this->saveXML();
    
    return array('_element');
  }

  /**
   * Cache the individual feed elements so they don't need to be
   * searched for on every operation.
   *
   * @return void
   */
  protected function _buildEntryCache() {
    $this->_entries = array();
    foreach ($this->_element->childNodes as $child) {
      if ($child->localName == $this->_entryElementName) {
        $this->_entries[] = $child;
      }
    }
  }

  /**
   * Get the number of entries in this feed object.
   *
   * @return integer Entry count.
   */
  public function count() {
    return count($this->_entries);
  }

  /**
   * Required by the Iterator interface.
   *
   * @return void
   */
  public function rewind() {
    $this->_entryIndex = 0;
  }

  /**
   * Required by the Iterator interface.
   *
   * @return mixed The current row, or null if no rows.
   */
  public function current() {
    return new $this->_entryClassName(null, $this->_entries[$this->_entryIndex]);
  }

  /**
   * Required by the Iterator interface.
   *
   * @return mixed The current row number (starts at 0), or NULL if no rows
   */
  public function key() {
    return $this->_entryIndex;
  }

  /**
   * Required by the Iterator interface.
   *
   * @return mixed The next row, or null if no more rows.
   */
  public function next() {
    ++ $this->_entryIndex;
  }

  /**
   * Required by the Iterator interface.
   *
   * @return boolean Whether the iteration is valid
   */
  public function valid() {
    return 0 <= $this->_entryIndex && $this->_entryIndex < $this->count();
  }

  /**
   * Generate the header of the feed when working in write mode
   *
   * @param  array $array the data to use
   * @return DOMElement root node
   */
  abstract protected function _mapFeedHeaders($array);

  /**
   * Generate the entries of the feed when working in write mode
   *
   * @param  DOMElement $root the root node to use
   * @param  array $array the data to use
   * @return DOMElement root node
   */
  abstract protected function _mapFeedEntries(DOMElement $root, $array);

  /**
   * Send feed to a http client with the correct header
   *
   * @throws Zend_Feed_Exception if headers have already been sent
   * @return void
   */
  abstract public function send();
}