<?php
/**
 * @package     Joomla.Plugin
 * @subpackage  User.token
 *
 * @copyright   (C) 2020 Open Source Matters, Inc. <https://www.joomla.org>
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\Plugin\User\Token\Field;

\defined('_JEXEC') or die;

use Joomla\CMS\Factory;
use Joomla\CMS\Form\Field\TextField;

/**
 * Joomlatoken field class
 *
 * @since  4.0.0
 */
class JoomlatokenField extends TextField
{
	/**
	 * Name of the layout being used to render the field
	 *
	 * @var    string
	 * @since  4.0.0
	 */
	protected $layout = 'plugins.user.token.token';

	/**
	 * Method to attach a Form object to the field.
	 *
	 * @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]".
	 *
	 * @return  boolean  True on success.
	 *
	 * @see     FormField::setup()
	 * @since   4.0.0
	 */
	public function setup(\SimpleXMLElement $element, $value, $group = null)
	{
		$ret = parent::setup($element, $value, $group);

		/**
		 * Security and privacy precaution: do not display the token field when the user being
		 * edited is not the same as the logged in user. Tokens are conceptually a combination of
		 * a username and password, therefore they should be treated in the same mode of
		 * confidentiality and privacy as passwords i.e. you can reset them for other users but NOT
		 * be able to see them, thus preventing impersonation attacks by a malicious administrator.
		 */
		$userId = $this->form->getData()->get('id');

		if ($userId != Factory::getUser()->id)
		{
			$this->hidden = true;
		}

		return $ret;
	}

	/**
	 * Method to get the field input markup.
	 *
	 * @return  string  The field input markup.
	 *
	 * @since   4.0.0
	 */
	protected function getInput()
	{
		// Do not display the token field when the user being edited is not the same as the logged in user
		if ($this->hidden)
		{
			return '';
		}

		return parent::getInput();
	}

	/**
	 * Returns the token formatted suitably for the user to copy.
	 *
	 * @param   string  $tokenSeed  The token seed data stored in the database
	 *
	 * @return  string
	 * @since   4.0.0
	 */
	private function getTokenForDisplay(string $tokenSeed): string
	{
		if (empty($tokenSeed))
		{
			return '';
		}

		$algorithm = $this->getAttribute('algo', 'sha256');

		try
		{
			$siteSecret = Factory::getApplication()->get('secret');
		}
		catch (\Exception $e)
		{
			$siteSecret = '';
		}

		// NO site secret? You monster!
		if (empty($siteSecret))
		{
			return '';
		}

		$rawToken  = base64_decode($tokenSeed);
		$tokenHash = hash_hmac($algorithm, $rawToken, $siteSecret);
		$userId    = $this->form->getData()->get('id');
		$message   = base64_encode("$algorithm:$userId:$tokenHash");

		if ($userId != Factory::getUser()->id)
		{
			$message = '';
		}

		return $message;
	}

	/**
	 * Get the data for the layout
	 *
	 * @return  array
	 *
	 * @since   4.0.0
	 */
	protected function getLayoutData()
	{
		$data          = parent::getLayoutData();
		$data['value'] = $this->getTokenForDisplay($this->value);

		return $data;
	}

	/**
	 * Get the layout paths
	 *
	 * @return  array
	 *
	 * @since   4.0.0
	 */
	protected function getLayoutPaths()
	{
		$template = Factory::getApplication()->getTemplate();

		return [
			JPATH_THEMES . '/' . $template . '/html/layouts',
			JPATH_SITE . '/layouts',
		];
	}
}