<?php

/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2017 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\CMS\Form\Rule;

use Joomla\CMS\Form\Form;
use Joomla\CMS\Form\FormRule;
use Joomla\Registry\Registry;

// phpcs:disable PSR1.Files.SideEffects
\defined('_JEXEC') or die;
// phpcs:enable PSR1.Files.SideEffects

/**
 * Form Rule class for the Joomla Platform.
 *
 * @since  1.7.0
 */
class ColorRule extends FormRule
{
    /**
     * 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 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   ?Form              $form     The form object for which the field is being tested.
     *
     * @return  boolean  True if the value is valid, false otherwise.
     *
     * @since   1.7.0
     */
    public function test(\SimpleXMLElement $element, $value, $group = null, ?Registry $input = null, ?Form $form = null)
    {
        $value = trim($value);

        // If the field is empty and not required, the field is valid.
        $required = ((string) $element['required'] === 'true' || (string) $element['required'] === 'required');

        if (!$required && empty($value)) {
            return true;
        }

        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;
    }
}