<?php
/**
 * @package     Joomla.Platform
 * @subpackage  Form
 *
 * @copyright   Copyright (C) 2005 - 2016 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die;

use Joomla\Registry\Registry;

/**
 * Form Rule class for the Joomla Platform.
 *
 * @since  11.2
 */
class JFormRuleColor extends JFormRule
{
	/**
	 * Method to test for a valid color in hexadecimal.
	 *
	 * @param   SimpleXMLElement  $element  The SimpleXMLElement 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   Registry          $input    An optional Registry object with the entire data set to validate against the entire form.
	 * @param   JForm             $form     The form object for which the field is being tested.
	 *
	 * @return  boolean  True if the value is valid, false otherwise.
	 *
	 * @since   11.2
	 */
	public function test(SimpleXMLElement $element, $value, $group = null, Registry $input = null, JForm $form = null)
	{
		$value = trim($value);

		if (empty($value))
		{
			// A color field can't be empty
			return false;
		}

		if ($value[0] != '#')
		{
			return false;
		}

		// Remove the leading # if present to validate the numeric part
		$value = ltrim($value, '#');

		// The value must be 6 or 3 characters long
		if (!((strlen($value) == 6 || strlen($value) == 3) && ctype_xdigit($value)))
		{
			return false;
		}

		return true;
	}
}
