<?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_Gdata
 * @subpackage App
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */

/**
 * @see Zend_Gdata_App_Entry
 */
require_once 'Zend/Gdata/App/Entry.php';

/**
 * @see Zend_Gdata_App_FeedSourceParent
 */
require_once 'Zend/Gdata/App/FeedSourceParent.php';

/**
 * Atom feed class
 *
 * @category   Zend
 * @package    Zend_Gdata
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Gdata_App_Feed extends Zend_Gdata_App_FeedSourceParent
        implements Iterator, ArrayAccess
{

    /**
     * The root xml element of this data element
     *
     * @var string
     */
    protected $_rootElement = 'feed';

    /**
     * Cache of feed entries.
     *
     * @var array
     */
    protected $_entry = array();

    /**
     * Current location in $_entry array
     *
     * @var int
     */
    protected $_entryIndex = 0;

    /**
     * Make accessing some individual elements of the feed easier.
     *
     * Special accessors 'entry' and 'entries' are provided so that if
     * you wish to iterate over an Atom feed's entries, you can do so
     * using foreach ($feed->entries as $entry) or foreach
     * ($feed->entry as $entry).
     *
     * @param  string $var The property to get.
     * @return mixed
     */
    public function __get($var)
    {
        switch ($var) {
            case 'entries':
                return $this;
            default:
                return parent::__get($var);
        }
    }

    /**
     * Retrieves the DOM model representing this object and all children
     *
     * @param DOMDocument $doc
     * @return DOMElement
     */
    public function getDOM($doc = null, $majorVersion = 1, $minorVersion = null)
    {
        $element = parent::getDOM($doc, $majorVersion, $minorVersion);
        foreach ($this->_entry as $entry) {
            $element->appendChild($entry->getDOM($element->ownerDocument));
        }
        return $element;
    }

    /**
     * Creates individual Entry objects of the appropriate type and
     * stores them in the $_entry array based upon DOM data.
     *
     * @param DOMNode $child The DOMNode to process
     */
    protected function takeChildFromDOM($child)
    {
        $absoluteNodeName = $child->namespaceURI . ':' . $child->localName;
        switch ($absoluteNodeName) {
        case $this->lookupNamespace('atom') . ':' . 'entry':
            $newEntry = new $this->_entryClassName($child);
            $newEntry->setHttpClient($this->getHttpClient());
            $this->_entry[] = $newEntry;
            break;
        default:
            parent::takeChildFromDOM($child);
            break;
        }
    }

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

    /**
     * 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 $this->_entry[$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();
    }

    /**
     * Gets the array of atom:entry elements contained within this
     * atom:feed representation
     *
     * @return array Zend_Gdata_App_Entry array
     */
    public function getEntry()
    {
        return $this->_entry;
    }

    /**
     * Sets the array of atom:entry elements contained within this
     * atom:feed representation
     *
     * @param array $value The array of Zend_Gdata_App_Entry elements
     * @return Zend_Gdata_App_Feed Provides a fluent interface
     */
    public function setEntry($value)
    {
        $this->_entry = $value;
        return $this;
    }

    /**
     * Adds an entry representation to the array of entries
     * contained within this feed
     *
     * @param Zend_Gdata_App_Entry An individual entry to add.
     * @return Zend_Gdata_App_Feed Provides a fluent interface
     */
    public function addEntry($value)
    {
        $this->_entry[] = $value;
        return $this;
    }

    /**
     * Required by the ArrayAccess interface
     *
     * @param int $key The index to set
     * @param Zend_Gdata_App_Entry $value The value to set
     * @return void
     */
    public function offsetSet($key, $value)
    {
        $this->_entry[$key] = $value;
    }

    /**
     * Required by the ArrayAccess interface
     *
     * @param int $key The index to get
     * @param Zend_Gdata_App_Entry $value The value to set
     */
    public function offsetGet($key)
    {
        if (array_key_exists($key, $this->_entry)) {
            return $this->_entry[$key];
        }
    }

    /**
     * Required by the ArrayAccess interface
     *
     * @param int $key The index to set
     * @param Zend_Gdata_App_Entry $value The value to set
     */
    public function offsetUnset($key)
    {
        if (array_key_exists($key, $this->_entry)) {
            unset($this->_entry[$key]);
        }
    }

    /**
     * Required by the ArrayAccess interface
     *
     * @param int $key The index to check for existence
     * @return boolean
     */
    public function offsetExists($key)
    {
        return (array_key_exists($key, $this->_entry));
    }

   /**
     * Retrieve the next set of results from this feed.
     *
     * @throws Zend_Gdata_App_Exception
     * @return mixed|null Returns the next set of results as a feed of the same
     *          class as this feed, or null if no results exist.
     */
    public function getNextFeed()
    {
        $nextLink = $this->getNextLink();
        if (!$nextLink) {
            require_once 'Zend/Gdata/App/HttpException.php';
            throw new Zend_Gdata_App_Exception('No link to next set ' .
            'of results found.');
        }
        $nextLinkHref = $nextLink->getHref();
        $service = new Zend_Gdata_App($this->getHttpClient());

        return $service->getFeed($nextLinkHref, get_class($this));
    }

   /**
     * Retrieve the previous set of results from this feed.
     *
     * @throws Zend_Gdata_App_Exception
     * @return mixed|null Returns the previous set of results as a feed of
     *          the same class as this feed, or null if no results exist.
     */
    public function getPreviousFeed()
    {
        $previousLink = $this->getPreviousLink();
        if (!$previousLink) {
            require_once 'Zend/Gdata/App/HttpException.php';
            throw new Zend_Gdata_App_Exception('No link to previous set ' .
            'of results found.');
        }
        $previousLinkHref = $previousLink->getHref();
        $service = new Zend_Gdata_App($this->getHttpClient());

        return $service->getFeed($previousLinkHref, get_class($this));
    }

}
