<?php
/**
 * @package     Joomla.Platform
 * @subpackage  Form
 *
 * @copyright   Copyright (C) 2005 - 2011 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die;

jimport('joomla.form.formrule');

/**
 * Form Rule class for the Joomla Framework.
 *
 * @package     Joomla.Platform
 * @subpackage  Form
 * @since       11.1
 */
class JFormRuleUsername extends JFormRule
{
    /**
     * Method to test the username for uniqueness.
     *
     * @param   object  $element    The JXMLElement object representing the <field /> tag for the
     *                              form field object.
     * @param   mixed   $value      The form field value to validate.
     * @param   string  $group      The field name group control value. This acts as as an array
     *                              container for the field. For example if the field has name="foo"
     *                              and the group value is set to "bar" then the full field name
     *                              would end up being "bar[foo]".
     * @param   object  $input      An optional JRegistry object with the entire data set to validate
     *                              against the entire form.
     * @param   object  $form       The form object for which the field is being tested.
     *
     * @return  boolean True if the value is valid, false otherwise.
     * @since   11.1
     * @throws  JException on invalid rule.
     */
    public function test(& $element, $value, $group = null, & $input = null, & $form = null)
    {
        // Get the database object and a new query object.
        $db     = JFactory::getDBO();
        $query  = $db->getQuery(true);

        // Build the query.
        $query->select('COUNT(*)');
        $query->from('#__users');
        $query->where('username = '.$db->quote($value));

        // Get the extra field check attribute.
        $userId = ($form instanceof JForm) ? $form->getValue('id') : '';
        $query->where($db->nameQuote('id').' <> '.(int) $userId);

        // Set and query the database.
        $db->setQuery($query);
        $duplicate = (bool) $db->loadResult();

        // Check for a database error.
        if ($db->getErrorNum()) {
            JError::raiseWarning(500, $db->getErrorMsg());
        }

        if ($duplicate) {
            return false;
        }

        return true;
    }
}