moodle-mod_htmlcert/classes/task/email_certificate_task.php

<?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/>.

/**
 * A scheduled task for emailing certificates.
 *
 * @package    mod_htmlcert
 * @copyright  2017 Mark Nelson <markn@moodle.com>, 2021 Klaus-Uwe Mitterer <kumitterer@kumi.systems>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
namespace mod_htmlcert\task;

use mod_htmlcert\helper;

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

/**
 * A scheduled task for emailing certificates.
 *
 * @package    mod_htmlcert
 * @copyright  2017 Mark Nelson <markn@moodle.com>, 2021 Klaus-Uwe Mitterer <kumitterer@kumi.systems>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class email_certificate_task extends \core\task\scheduled_task {

    /**
     * Get a descriptive name for this task (shown to admins).
     *
     * @return string
     */
    public function get_name() {
        return get_string('taskemailcertificate', 'htmlcert');
    }

    /**
     * Execute.
     */
    public function execute() {
        global $DB, $PAGE;

        // Get all the certificates that have requested someone get emailed.
        $emailotherslengthsql = $DB->sql_length('c.emailothers');
        $sql = "SELECT c.*, ct.id as templateid, ct.name as templatename, ct.contextid, co.id as courseid,
                       co.fullname as coursefullname, co.shortname as courseshortname
                  FROM {htmlcert} c
                  JOIN {htmlcert_templates} ct
                    ON c.templateid = ct.id
                  JOIN {course} co
                    ON c.course = co.id
                 WHERE (c.emailstudents = :emailstudents
                        OR c.emailteachers = :emailteachers
                        OR $emailotherslengthsql >= 3)";
        if (!$htmlcerts = $DB->get_records_sql($sql, array('emailstudents' => 1, 'emailteachers' => 1))) {
            return;
        }

        // The renderers used for sending emails.
        $htmlrenderer = $PAGE->get_renderer('mod_htmlcert', 'email', 'htmlemail');
        $textrenderer = $PAGE->get_renderer('mod_htmlcert', 'email', 'textemail');

        // Get the context.
        $context = \context::instance_by_id($htmlcert->contextid);

        // Set the $PAGE context - this ensure settings, such as language, are kept and don't default to the site settings.
        $PAGE->set_context($context);

        // Get the person we are going to send this email on behalf of.
        $userfrom = \core_user::get_noreply_user();

        // Store teachers for later.
        $teachers = get_enrolled_users($context, 'moodle/course:update');

        $courseshortname = format_string($htmlcert->courseshortname, true, array('context' => $context));
        $coursefullname = format_string($htmlcert->coursefullname, true, array('context' => $context));
        $certificatename = format_string($htmlcert->name, true, array('context' => $context));

        // Used to create the email subject.
        $info = new \stdClass;
        $info->coursename = $courseshortname; // Added for BC, so users who have edited the string don't lose this value.
        $info->courseshortname = $courseshortname;
        $info->coursefullname = $coursefullname;
        $info->certificatename = $certificatename;

        // Get a list of all the issues.
        $userfields = helper::get_all_user_name_fields('u');
        $sql = "SELECT u.id, u.username, $userfields, u.email, ci.id as issueid, ci.emailed
                    FROM {htmlcert_issues} ci
                    JOIN {user} u
                    ON ci.userid = u.id
                    WHERE ci.htmlcertid = :htmlcertid";
        $issuedusers = $DB->get_records_sql($sql, array('htmlcertid' => $htmlcert->id));

        // Now, get a list of users who can access the certificate but have not yet.
        $enrolledusers = get_enrolled_users(\context_course::instance($htmlcert->courseid), 'mod/htmlcert:view');
        foreach ($enrolledusers as $enroluser) {
            // Check if the user has already been issued.
            if (in_array($enroluser->id, array_keys((array) $issuedusers))) {
                continue;
            }

            // Now check if the certificate is not visible to the current user.
            $cm = get_fast_modinfo($htmlcert->courseid, $enroluser->id)->instances['htmlcert'][$htmlcert->id];
            if (!$cm->uservisible) {
                continue;
            }

            // Don't want to email those with the capability to manage the certificate.
            if (has_capability('mod/htmlcert:manage', $context, $enroluser->id)) {
                continue;
            }

            // Only email those with the capability to receive the certificate.
            if (!has_capability('mod/htmlcert:receiveissue', $context, $enroluser->id)) {
                continue;
            }

            // Check that they have passed the required time.
            if (!empty($htmlcert->requiredtime)) {
                if (\mod_htmlcert\certificate::get_course_time($htmlcert->courseid,
                        $enroluser->id) < ($htmlcert->requiredtime * 60)) {
                    continue;
                }
            }

            // Ensure the cert hasn't already been issued, e.g via the UI (view.php) - a race condition.
            $issueid = $DB->get_field('htmlcert_issues', 'id',
                array('userid' => $enroluser->id, 'htmlcertid' => $htmlcert->id), IGNORE_MULTIPLE);
            if (empty($issueid)) {
                // Ok, issue them the certificate.
                $issueid = \mod_htmlcert\certificate::issue_certificate($htmlcert->id, $enroluser->id);
            }

            // Add them to the array so we email them.
            $enroluser->issueid = $issueid;
            $enroluser->emailed = 0;
            $issuedusers[] = $enroluser;
        }

        // Remove all the users who have already been emailed.
        foreach ($issuedusers as $key => $issueduser) {
            if ($issueduser->emailed) {
                unset($issuedusers[$key]);
            }
        }

        // If there are no users to email we can return early.
        if (!$issuedusers) {
            continue;
        }

        // Create a directory to store the PDF we will be sending.
        $tempdir = make_temp_directory('certificate/attachment');
        if (!$tempdir) {
            return;
        }

        // Now, email the people we need to.
        foreach ($issuedusers as $user) {
            // Set up the user.
            cron_setup_user($user);

            $userfullname = fullname($user);
            $info->userfullname = $userfullname;

            // Now, get the PDF.
            $template = new \stdClass();
            $template->id = $htmlcert->templateid;
            $template->name = $htmlcert->templatename;
            $template->contextid = $htmlcert->contextid;
            $template = new \mod_htmlcert\template($template);
            $filecontents = $template->generate_pdf(false, $user->id, true);

            // Set the name of the file we are going to send.
            $filename = $courseshortname . '_' . $certificatename;
            $filename = \core_text::entities_to_utf8($filename);
            $filename = strip_tags($filename);
            $filename = rtrim($filename, '.');
            $filename = str_replace('&', '_', $filename) . '.pdf';

            // Create the file we will be sending.
            $tempfile = $tempdir . '/' . md5(microtime() . $user->id) . '.pdf';
            file_put_contents($tempfile, $filecontents);

            if ($htmlcert->emailstudents) {
                $renderable = new \mod_htmlcert\output\email_certificate(true, $userfullname, $courseshortname,
                    $coursefullname, $certificatename, $htmlcert->contextid);

                $subject = get_string('emailstudentsubject', 'htmlcert', $info);
                $message = $textrenderer->render($renderable);
                $messagehtml = $htmlrenderer->render($renderable);
                email_to_user($user, fullname($userfrom), html_entity_decode($subject), $message, $messagehtml,
                    $tempfile, $filename);
            }

            if ($htmlcert->emailteachers) {
                $renderable = new \mod_htmlcert\output\email_certificate(false, $userfullname, $courseshortname,
                    $coursefullname, $certificatename, $htmlcert->contextid);

                $subject = get_string('emailnonstudentsubject', 'htmlcert', $info);
                $message = $textrenderer->render($renderable);
                $messagehtml = $htmlrenderer->render($renderable);
                foreach ($teachers as $teacher) {
                    email_to_user($teacher, fullname($userfrom), html_entity_decode($subject), $message, $messagehtml,
                        $tempfile, $filename);
                }
            }

            if (!empty($htmlcert->emailothers)) {
                $others = explode(',', $htmlcert->emailothers);
                foreach ($others as $email) {
                    $email = trim($email);
                    if (validate_email($email)) {
                        $renderable = new \mod_htmlcert\output\email_certificate(false, $userfullname,
                            $courseshortname, $coursefullname, $certificatename, $htmlcert->contextid);

                        $subject = get_string('emailnonstudentsubject', 'htmlcert', $info);
                        $message = $textrenderer->render($renderable);
                        $messagehtml = $htmlrenderer->render($renderable);

                        $emailuser = new \stdClass();
                        $emailuser->id = -1;
                        $emailuser->email = $email;
                        email_to_user($emailuser, fullname($userfrom), html_entity_decode($subject), $message,
                            $messagehtml, $tempfile, $filename);
                    }
                }
            }

            // Set the field so that it is emailed.
            $DB->set_field('htmlcert_issues', 'emailed', 1, array('id' => $user->issueid));
        }
    }
}