<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Anobody can login with any password.
 *
 * @package auth_macaroons
 * @author Brendan Abolivier
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 */

defined('MOODLE_INTERNAL') || die();

require_once($CFG->libdir.'/authlib.php');

require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Macaroon.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Caveat.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Packet.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Utils.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Verifier.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Exceptions/CaveatUnsatisfiedException.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Exceptions/InvalidMacaroonKeyException.php');
require_once($CFG->dirroot.'/auth/macaroons/Macaroons/Exceptions/SignatureMismatchException.php');

use Macaroons\Macaroon;
use Macaroons\Verifier;


/**
 * Plugin for no authentication.
 */
class auth_plugin_macaroons extends auth_plugin_base {

	/**
	 * Constructor.
	 */
	public function __construct() {
		$this->authtype = 'macaroons';
	}

	function loginpage_hook() {
		global $message;
		$message = "";
		if(!empty($_COOKIE['das-macaroon'])) {
			try {
				$m = Macaroon::deserialize($_COOKIE['das-macaroon']);
				$frm = new stdClass();
				$frm->username = $m->getIdentifier();
				$frm->password = 'passwdMacaroons';
				$v = new Verifier();
				$v->setCallbacks([
					function($a) {
						return !strcmp($a, "status = student");
					}
				]);
				if($v->verify($m, "pocsecret")) {
					$frm = new stdClass();
					$frm->username = $m->getIdentifier();
					$frm->password = 'passwdMacaroons';
				}
			} catch(Exception $e) {
				$message = $e->getMessage();
			}
			authenticate_user_login($frm->username, sesskey());
		}
	}

	/**
	 * Old syntax of class constructor. Deprecated in PHP7.
	 *
	 * @deprecated since Moodle 3.1
	 */
	public function auth_plugin_macaroons() {
		debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
		self::__construct();
	}

	/**
	 * Returns true if the username and password work or don't exist and false
	 * if the user exists and the password is wrong.
	 *
	 * @param string $username The username
	 * @param string $password The password
	 * @return bool Authentication success or failure.
	 */
	function user_login ($username, $password) {
		global $message;
		if(!empty($message)) {
			return false;
		} elseif(!empty($_COOKIE['das-macaroon'])) {
			return true;
		}
	}

	/**
	 * Updates the user's password.
	 *
	 * called when the user password is updated.
	 *
	 * @param  object  $user		User table object
	 * @param  string  $newpassword Plaintext password
	 * @return boolean result
	 *
	 */
	function user_update_password($user, $newpassword) {
		$user = get_complete_user_data('id', $user->id);
		// This will also update the stored hash to the latest algorithm
		// if the existing hash is using an out-of-date algorithm (or the
		// legacy md5 algorithm).
		return update_internal_user_password($user, $newpassword);
	}

	function prevent_local_passwords() {
		return false;
	}

	/**
	 * Returns true if this authentication plugin is 'internal'.
	 *
	 * @return bool
	 */
	function is_internal() {
		return false;
	}

	/**
	 * Returns true if this authentication plugin can change the user's
	 * password.
	 *
	 * @return bool
	 */
	function can_change_password() {
		return true;
	}

	/**
	 * Returns the URL for changing the user's pw, or empty if the default can
	 * be used.
	 *
	 * @return moodle_url
	 */
	function change_password_url() {
		return null;
	}

	/**
	 * Returns true if plugin allows resetting of internal password.
	 *
	 * @return bool
	 */
	function can_reset_password() {
		return true;
	}

	/**
	 * Returns true if plugin can be manually set.
	 *
	 * @return bool
	 */
	function can_be_manually_set() {
		return true;
	}

	/**
	 * Prints a form for configuring this authentication plugin.
	 *
	 * This function is called from admin/auth.php, and outputs a full page with
	 * a form for configuring this plugin.
	 *
	 * @param array $page An object containing all the data for this page.
	function config_form($config, $err, $user_fields) {
		include "config.html";
	}
	 */

	/**
	 * Processes and stores configuration data for this authentication plugin.
	 */
	function process_config($config) {
		return true;
	}

}