<?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/>.

/**
 * Endpoint for the verification email link.
 *
 * @package    core
 * @subpackage badges
 * @copyright  2016 Jake Dallimore <jrhdallimore@gmail.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
require_once(__DIR__ . '/../config.php');
require_once($CFG->libdir . '/badgeslib.php');

$data = optional_param('data', '', PARAM_RAW);
require_login();
$PAGE->set_url('/badges/backpackemailverify.php');
$PAGE->set_context(context_user::instance($USER->id));
$redirect = '/badges/mybackpack.php';

// Confirm the secret and create the backpack connection.
$storedsecret = get_user_preferences('badges_email_verify_secret');
if (!is_null($storedsecret)) {
    if ($data === $storedsecret) {
        $storedemail = get_user_preferences('badges_email_verify_address');
        $backpackid = get_user_preferences('badges_email_verify_backpackid');
        $password = get_user_preferences('badges_email_verify_password');

        $backpack = badges_get_site_backpack($backpackid);

        $data = new stdClass();
        $data->email = $storedemail;
        $data->password = $password;
        $data->externalbackpackid = $backpackid;
        $bp = new \core_badges\backpack_api($backpack, $data);

        // Make sure we have all the required information before trying to save the connection.
        $backpackuid = $bp->authenticate();
        if (empty($backpackuid) || !empty($backpackuid->error)) {
            redirect(new moodle_url($redirect), get_string('backpackconnectionunexpectedresult', 'badges', $backpackuid->error),
                null, \core\output\notification::NOTIFY_ERROR);
        }

        $values = [
            'userid' => $USER->id,
            'backpackemail' => $data->email,
            'externalbackpackid' => $backpackid,
            'backpackuid' => $backpackuid,
            'autosync' => 0,
            'password' => $password
        ];
        badges_save_backpack_credentials((object) $values);

        // Remove the verification vars and redirect to the mypackpack page.
        unset_user_preference('badges_email_verify_secret');
        unset_user_preference('badges_email_verify_address');
        unset_user_preference('badges_email_verify_backpackid');
        unset_user_preference('badges_email_verify_password');
        redirect(new moodle_url($redirect), get_string('backpackemailverifysuccess', 'badges'),
            null, \core\output\notification::NOTIFY_SUCCESS);
    } else {
        // Stored secret doesn't match the supplied secret. Take user back to the mybackpack page and present a warning message.
        redirect(new moodle_url($redirect), get_string('backpackemailverifytokenmismatch', 'badges'),
            null, \core\output\notification::NOTIFY_ERROR);
    }
} else {
    // Stored secret is null. Either the email address has already been verified, or there is no record of a verification attempt
    // for the current user. Either way, just redirect to the mybackpack page.
    redirect(new moodle_url($redirect));
}