<?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) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Util.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/**

 * Utility class for static functions needed by Zend_Gdata_App

 *

 * @category   Zend

 * @package    Zend_Gdata

 * @subpackage App

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Gdata_App_Util

{

    /**

     *  Convert timestamp into RFC 3339 date string.

     *  2005-04-19T15:30:00

     *

     * @param int $timestamp

     * @throws Zend_Gdata_App_InvalidArgumentException

     */

    public static function formatTimestamp($timestamp)

    {

        $rfc3339 = '/^(\d{4})\-?(\d{2})\-?(\d{2})((T|t)(\d{2})\:?(\d{2})' .

                   '\:?(\d{2})(\.\d{1,})?((Z|z)|([\+\-])(\d{2})\:?(\d{2})))?$/';

        if (ctype_digit($timestamp)) {

            return gmdate('Y-m-d\TH:i:sP', $timestamp);

        } elseif (preg_match($rfc3339, $timestamp) > 0) {

            // timestamp is already properly formatted

            return $timestamp;

        } else {

            $ts = strtotime($timestamp);

            if ($ts === false) {

                require_once 'Zend/Gdata/App/InvalidArgumentException.php';

                throw new Zend_Gdata_App_InvalidArgumentException("Invalid timestamp: $timestamp.");

            }

            return date('Y-m-d\TH:i:s', $ts);

        }

    }

    /** Find the greatest key that is less than or equal to a given upper

      * bound, and return the value associated with that key.

      *

      * @param integer|null $maximumKey The upper bound for keys. If null, the

      *        maxiumum valued key will be found.

      * @param array $collection An two-dimensional array of key/value pairs

      *        to search through.

      * @returns mixed The value corresponding to the located key.

      * @throws Zend_Gdata_App_Exception Thrown if $collection is empty.

      */

    public static function findGreatestBoundedValue($maximumKey, $collection)

    {

        $found = false;

        $foundKey = $maximumKey;

        // Sanity check: Make sure that the collection isn't empty

        if (sizeof($collection) == 0) {

            require_once 'Zend/Gdata/App/Exception.php';

            throw new Zend_Gdata_App_Exception("Empty namespace collection encountered.");

        }

        if ($maximumKey === null) {

            // If the key is null, then we return the maximum available

            $keys = array_keys($collection);

            sort($keys);

            $found = true;

            $foundKey = end($keys);

        } else {

            // Otherwise, we optimistically guess that the current version

            // will have a matching namespce. If that fails, we decrement the

            // version until we find a match.

            while (!$found && $foundKey >= 0) {

                if (array_key_exists($foundKey, $collection))

                    $found = true;

                else

                    $foundKey--;

            }

        }

        // Guard: A namespace wasn't found. Either none were registered, or

        // the current protcol version is lower than the maximum namespace.

        if (!$found) {

            require_once 'Zend/Gdata/App/Exception.php';

            throw new Zend_Gdata_App_Exception("Namespace compatible with current protocol not found.");

        }

        return $foundKey;

    }

}