<?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;

defined('JPATH_PLATFORM') or die;

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

/**
 * Form Rule class for the Joomla Platform.
 *
 * @since  1.7.0
 */
class EqualsRule extends FormRule
{
	/**
	 * Method to test if two values are equal. To use this rule, the form
	 * XML needs a validate attribute of equals and a field attribute
	 * that is equal to the field to test against.
	 *
	 * @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
	 * @throws  \InvalidArgumentException
	 * @throws  \UnexpectedValueException
	 */
	public function test(\SimpleXMLElement $element, $value, $group = null, Registry $input = null, Form $form = null)
	{
		$field = (string) $element['field'];

		// Check that a validation field is set.
		if (!$field)
		{
			throw new \UnexpectedValueException(sprintf('$field empty in %s::test', get_class($this)));
		}

		if (is_null($form))
		{
			throw new \InvalidArgumentException(sprintf('The value for $form must not be null in %s', get_class($this)));
		}

		if (is_null($input))
		{
			throw new \InvalidArgumentException(sprintf('The value for $input must not be null in %s', get_class($this)));
		}

		$test = $input->get($field);

		if (isset($group) && $group !== '')
		{
			$test = $input->get($group . '.' . $field);
		}

		// Test the two values against each other.
		return $value == $test;
	}
}