PHP sort_by_roleassignment_authority函数代码示例

     die;
 }
 // ALL CLEAR !
 $DB->insert_record("enrol_paypal", $data);
 if ($plugin_instance->enrolperiod) {
     $timestart = time();
     $timeend = $timestart + $plugin_instance->enrolperiod;
 } else {
     $timestart = 0;
     $timeend = 0;
 }
 // Enrol user
 $plugin->enrol_user($plugin_instance, $user->id, $plugin_instance->roleid, $timestart, $timeend);
 // Pass $view=true to filter hidden caps if the user cannot see them
 if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
     $users = sort_by_roleassignment_authority($users, $context);
     $teacher = array_shift($users);
 } else {
     $teacher = false;
 }
 $mailstudents = $plugin->get_config('mailstudents');
 $mailteachers = $plugin->get_config('mailteachers');
 $mailadmins = $plugin->get_config('mailadmins');
 $shortname = format_string($course->shortname, true, array('context' => $context));
 if (!empty($mailstudents)) {
     $a->coursename = format_string($course->fullname, true, array('context' => $coursecontext));
     $a->profileurl = "{$CFG->wwwroot}/user/view.php?id={$user->id}";
     $eventdata = new stdClass();
     $eventdata->modulename = 'moodle';
     $eventdata->component = 'enrol_paypal';
     $eventdata->name = 'paypal_enrolment';

 /**
 * Notify users about enrolments that are going to expire soon!
 * This function is run by admin/cron.php
 * @return void
 */
 function cron()
 {
     global $CFG, $USER, $SITE;
     if (!isset($CFG->lastexpirynotify)) {
         set_config('lastexpirynotify', 0);
     }
     // notify once a day only - TODO: add some tz handling here, maybe use timestamps
     if ($CFG->lastexpirynotify == date('Ymd')) {
         return;
     }
     if ($rs = get_recordset_select('course', 'enrolperiod > 0 AND expirynotify > 0 AND expirythreshold > 0')) {
         $cronuser = clone $USER;
         $admin = get_admin();
         while ($course = rs_fetch_next_record($rs)) {
             $a = new object();
             $a->coursename = $course->shortname . '/' . $course->fullname;
             // must be processed by format_string later
             $a->threshold = $course->expirythreshold / 86400;
             $a->extendurl = $CFG->wwwroot . '/user/index.php?id=' . $course->id;
             $a->current = array();
             $a->past = array();
             $expiry = time() + $course->expirythreshold;
             $cname = $course->fullname;
             /// Get all the manual role assignments for this course that have expired.
             if (!($context = get_context_instance(CONTEXT_COURSE, $course->id))) {
                 continue;
             }
             if ($oldenrolments = get_records_sql("\n                      SELECT u.*, ra.timeend\n                        FROM {$CFG->prefix}user u\n                             JOIN {$CFG->prefix}role_assignments ra ON (ra.userid = u.id)\n                        WHERE ra.contextid = {$context->id}\n                              AND ra.timeend > 0 AND ra.timeend <= {$expiry}\n                              AND ra.enrol = 'manual'")) {
                 // inform user who can assign roles or admin
                 if ($teachers = get_users_by_capability($context, 'moodle/role:assign', '', '', '', '', '', '', false)) {
                     $teachers = sort_by_roleassignment_authority($teachers, $context);
                     $teacher = reset($teachers);
                 } else {
                     $teachers = array($admin);
                     $teacher = $admin;
                 }
                 $a->teacherstr = fullname($teacher, true);
                 foreach ($oldenrolments as $user) {
                     /// Email all users about to expire
                     $a->studentstr = fullname($user, true);
                     if ($user->timeend < $expiry - 86400) {
                         $a->past[] = fullname($user) . " <{$user->email}>";
                     } else {
                         $a->current[] = fullname($user) . " <{$user->email}>";
                         if ($course->notifystudents) {
                             // Send this guy notice
                             // setup global $COURSE properly - needed for languages
                             $USER = $user;
                             course_setup($course);
                             $a->coursename = format_string($cname);
                             $a->course = $a->coursename;
                             $strexpirynotifystudentsemail = get_string('expirynotifystudentsemail', '', $a);
                             $strexpirynotify = get_string('expirynotify');
                             email_to_user($user, $teacher, format_string($SITE->fullname) . ' ' . $strexpirynotify, $strexpirynotifystudentsemail);
                         }
                     }
                 }
                 $a->current = implode("\n", $a->current);
                 $a->past = implode("\n", $a->past);
                 if ($a->current || $a->past) {
                     foreach ($teachers as $teacher) {
                         // setup global $COURSE properly - needed for languages
                         $USER = $teacher;
                         course_setup($course);
                         $a->coursename = format_string($cname);
                         $strexpirynotifyemail = get_string('expirynotifyemail', '', $a);
                         $strexpirynotify = get_string('expirynotify');
                         email_to_user($teacher, $admin, $a->coursename . ' ' . $strexpirynotify, $strexpirynotifyemail);
                     }
                 }
             }
         }
         $USER = $cronuser;
         course_setup($SITE);
         // More environment
     }
     set_config('lastexpirynotify', date('Ymd'));
 }

 /**
  * Returns the user who is responsible for self enrolments in given instance.
  *
  * Usually it is the first editing teacher - the person with "highest authority"
  * as defined by sort_by_roleassignment_authority() having 'enrol/self:manage'
  * capability.
  *
  * @param int $instanceid enrolment instance id
  * @return stdClass user record
  */
 protected function get_enroller($instanceid)
 {
     global $DB;
     if ($this->lasternollerinstanceid == $instanceid and $this->lasternoller) {
         return $this->lasternoller;
     }
     $instance = $DB->get_record('enrol', array('id' => $instanceid, 'enrol' => $this->get_name()), '*', MUST_EXIST);
     $context = context_course::instance($instance->courseid);
     if ($users = get_enrolled_users($context, 'enrol/self:manage')) {
         $users = sort_by_roleassignment_authority($users, $context);
         $this->lasternoller = reset($users);
         unset($users);
     } else {
         $this->lasternoller = parent::get_enroller($instanceid);
     }
     $this->lasternollerinstanceid = $instanceid;
     return $this->lasternoller;
 }

 /**
  * Creates course enrol form, checks if form submitted
  * and enrols user if necessary. It can also redirect.
  *
  * @param stdClass $instance
  * @return string html text, usually a form in a text box
  */
 function enrol_page_hook(stdClass $instance)
 {
     global $CFG, $USER, $OUTPUT, $PAGE, $DB;
     ob_start();
     if ($DB->record_exists('user_enrolments', array('userid' => $USER->id, 'enrolid' => $instance->id))) {
         return ob_get_clean();
     }
     if ($instance->enrolstartdate != 0 && $instance->enrolstartdate > time()) {
         return ob_get_clean();
     }
     if ($instance->enrolenddate != 0 && $instance->enrolenddate < time()) {
         return ob_get_clean();
     }
     $course = $DB->get_record('course', array('id' => $instance->courseid));
     $context = context_course::instance($course->id);
     $shortname = format_string($course->shortname, true, array('context' => $context));
     $strloginto = get_string("loginto", "", $shortname);
     $strcourses = get_string("courses");
     // Pass $view=true to filter hidden caps if the user cannot see them
     if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
         $users = sort_by_roleassignment_authority($users, $context);
         $teacher = array_shift($users);
     } else {
         $teacher = false;
     }
     if ((double) $instance->cost <= 0) {
         $cost = (double) $this->get_config('cost');
     } else {
         $cost = (double) $instance->cost;
     }
     if (abs($cost) < 0.01) {
         // no cost, other enrolment methods (instances) should be used
         echo '<p>' . get_string('nocost', 'enrol_paypal') . '</p>';
     } else {
         // Calculate localised and "." cost, make sure we send PayPal the same value,
         // please note PayPal expects amount with 2 decimal places and "." separator.
         $localisedcost = format_float($cost, 2, true);
         $cost = format_float($cost, 2, false);
         if (isguestuser()) {
             // force login only for guest user, not real users with guest role
             if (empty($CFG->loginhttps)) {
                 $wwwroot = $CFG->wwwroot;
             } else {
                 // This actually is not so secure ;-), 'cause we're
                 // in unencrypted connection...
                 $wwwroot = str_replace("http://", "https://", $CFG->wwwroot);
             }
             echo '<div class="mdl-align"><p>' . get_string('paymentrequired') . '</p>';
             echo '<p><b>' . get_string('cost') . ": {$instance->currency} {$localisedcost}" . '</b></p>';
             echo '<p><a href="' . $wwwroot . '/login/">' . get_string('loginsite') . '</a></p>';
             echo '</div>';
         } else {
             //Sanitise some fields before building the PayPal form
             $coursefullname = format_string($course->fullname, true, array('context' => $context));
             $courseshortname = $shortname;
             $userfullname = fullname($USER);
             $userfirstname = $USER->firstname;
             $userlastname = $USER->lastname;
             $useraddress = $USER->address;
             $usercity = $USER->city;
             $instancename = $this->get_instance_name($instance);
             include $CFG->dirroot . '/enrol/paypal/enrol.html';
         }
     }
     return $OUTPUT->box(ob_get_clean());
 }

/**
 * Sends the student their issued certificate from moddata as an email
 * attachment.
 *
 * @param stdClass $user
 * @param stdClass $course
 * @param stdClass $certificate
 * @param stdClass $certrecord
 * @param stdClass $context
 */
function certificate_email_students($user, $course, $certificate, $certrecord, $context)
{
    global $DB, $USER;
    if ($certrecord->mailed > 0) {
        return;
    }
    // Get teachers
    if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
        $users = sort_by_roleassignment_authority($users, $context);
        $teacher = array_shift($users);
    }
    // If we haven't found a teacher yet, look for a non-editing teacher in this course.
    if (empty($teacher) && ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true))) {
        $users = sort_by_roleassignment_authority($users, $context);
        $teacher = array_shift($users);
    }
    $info = new stdClass();
    $info->username = fullname($user);
    $info->certificate = format_string($certificate->name, true);
    $info->course = format_string($course->fullname, true);
    $from = fullname($teacher);
    $subject = $info->course . ': ' . $info->certificate;
    $message = get_string('emailstudenttext', 'certificate', $info) . "\n";
    // Make the HTML version more XHTML happy  (&)
    $messagehtml = text_to_html(get_string('emailstudenttext', 'certificate', $info));
    $user->mailformat = 0;
    // Always send HTML version as well
    $filename = clean_filename($certificate->name . '.pdf');
    // Get hashed pathname
    $fs = get_file_storage();
    $component = 'mod_certificate';
    $filearea = 'issue';
    $filepath = '/';
    $files = $fs->get_area_files($context->id, $component, $filearea, $certrecord->id);
    foreach ($files as $f) {
        $filepathname = $f->get_contenthash();
    }
    $attachment = 'filedir/' . certificate_path_from_hash($filepathname) . '/' . $filepathname;
    $attachname = $filename;
    $DB->set_field('certificate_issues', 'mailed', '1', array('certificateid' => $certificate->id, 'userid' => $user->id));
    return email_to_user($user, $from, $subject, $message, $messagehtml, $attachment, $attachname);
}

/**
 * Sends the student their issued certificate from moddata as an email
 * attachment.
 *
 * @param stdClass $course
 * @param stdClass $certificate
 * @param stdClass $certrecord
 * @param stdClass $context
 * @param string $filecontents the PDF file contents
 * @param string $filename
 * @return bool Returns true if mail was sent OK and false if there was an error.
 */
function certificate_email_student($course, $certificate, $certrecord, $context, $filecontents, $filename)
{
    global $USER;
    // Get teachers
    if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
        $users = sort_by_roleassignment_authority($users, $context);
        $teacher = array_shift($users);
    }
    // If we haven't found a teacher yet, look for a non-editing teacher in this course.
    if (empty($teacher) && ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true))) {
        $users = sort_by_roleassignment_authority($users, $context);
        $teacher = array_shift($users);
    }
    // Ok, no teachers, use administrator name
    if (empty($teacher)) {
        $teacher = fullname(get_admin());
    }
    $info = new stdClass();
    $info->username = fullname($USER);
    $info->certificate = format_string($certificate->name, true);
    $info->course = format_string($course->fullname, true);
    $from = fullname($teacher);
    $subject = $info->course . ': ' . $info->certificate;
    $message = get_string('emailstudenttext', 'certificate', $info) . "\n";
    // Make the HTML version more XHTML happy  (&)
    $messagehtml = text_to_html(get_string('emailstudenttext', 'certificate', $info));
    $tempdir = make_temp_directory('certificate/attachment');
    if (!$tempdir) {
        return false;
    }
    $tempfile = $tempdir . '/' . md5(sesskey() . microtime() . $USER->id . '.pdf');
    $fp = fopen($tempfile, 'w+');
    fputs($fp, $filecontents);
    fclose($fp);
    $prevabort = ignore_user_abort(true);
    $result = email_to_user($USER, $from, $subject, $message, $messagehtml, $tempfile, $filename);
    @unlink($tempfile);
    ignore_user_abort($prevabort);
    return $result;
}

/**
 * Sends the student their issued iomadcertificate from moddata as an email
 * attachment.
 *
 * @param stdClass $course
 * @param stdClass $iomadcertificate
 * @param stdClass $certrecord
 * @param stdClass $context
 */
function iomadcertificate_email_student($course, $iomadcertificate, $certrecord, $context)
{
    global $DB, $USER;
    // Get teachers
    if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
        $users = sort_by_roleassignment_authority($users, $context);
        $teacher = array_shift($users);
    }
    // If we haven't found a teacher yet, look for a non-editing teacher in this course.
    if (empty($teacher) && ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true))) {
        $users = sort_by_roleassignment_authority($users, $context);
        $teacher = array_shift($users);
    }
    // Ok, no teachers, use administrator name
    if (empty($teacher)) {
        $teacher = fullname(get_admin());
    }
    $info = new stdClass();
    $info->username = fullname($USER);
    $info->iomadcertificate = format_string($iomadcertificate->name, true);
    $info->course = format_string($course->fullname, true);
    $from = fullname($teacher);
    $subject = $info->course . ': ' . $info->iomadcertificate;
    $message = get_string('emailstudenttext', 'iomadcertificate', $info) . "\n";
    // Make the HTML version more XHTML happy  (&)
    $messagehtml = text_to_html(get_string('emailstudenttext', 'iomadcertificate', $info));
    // Remove full-stop at the end if it exists, to avoid "..pdf" being created and being filtered by clean_filename
    $certname = rtrim($iomadcertificate->name, '.');
    $filename = clean_filename("{$certname}.pdf");
    // Get hashed pathname
    $fs = get_file_storage();
    $component = 'mod_iomadcertificate';
    $filearea = 'issue';
    $filepath = '/';
    $files = $fs->get_area_files($context->id, $component, $filearea, $certrecord->id);
    foreach ($files as $f) {
        $filepathname = $f->get_contenthash();
    }
    $attachment = 'filedir/' . iomadcertificate_path_from_hash($filepathname) . '/' . $filepathname;
    $attachname = $filename;
    return email_to_user($USER, $from, $subject, $message, $messagehtml, $attachment, $attachname);
}

 /**
  * Creates course enrol form, checks if form submitted
  * and enrols user if necessary. It can also redirect.
  * It basically controls what the user sees it generates the enrollform e.t.c
  *
  *
  * @param stdClass $instance
  * @return string html text, usually a form in a text box
  */
 function enrol_page_hook(stdClass $instance)
 {
     global $CFG, $USER, $OUTPUT, $PAGE, $DB;
     ob_start();
     $select = "userid = '" . $USER->id . "' AND enrolid ='" . $instance->id . "' AND timeend >'" . time() . "'";
     if ($DB->record_exists_select('user_enrolments', $select, array($params = null))) {
         return ob_get_clean();
     }
     if ($instance->enrolstartdate != 0 && $instance->enrolstartdate > time()) {
         return ob_get_clean();
     }
     if ($instance->enrolenddate != 0 && $instance->enrolenddate < time()) {
         return ob_get_clean();
     }
     $course = $DB->get_record('course', array('id' => $instance->courseid));
     $context = context_course::instance($course->id);
     $shortname = format_string($course->shortname, true, array('context' => $context));
     $strloginto = get_string("loginto", "", $shortname);
     $strcourses = get_string("courses");
     // Pass $view=true to filter hidden caps if the user cannot see them.
     if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
         $users = sort_by_roleassignment_authority($users, $context);
         $teacher = array_shift($users);
         //returns the first element in the array shifting the
         //rest one position lower
     } else {
         $teacher = false;
     }
     if ((double) $instance->cost <= 0) {
         $cost = (double) $this->get_config('cost');
         //get_config fetches from the original configuration settings
     } else {
         $cost = (double) $instance->cost;
     }
     if (abs($cost) < 0.01) {
         echo '<p>' . get_string('nocost', 'ipay') . '</p>';
     } else {
         //Calculate localised cost and "." cost, make sure we send Ipay the same value
         //please note ipay expects ammount with 2 decimal places and "." seperator.
         $localisedcost = format_float($cost, 2, true);
         if (isguestuser()) {
             if (empty($CFG->loginhttps)) {
                 $wwwroot = $CFG->wwwroot;
             } else {
                 //This is not so secure ;-) cause we're
                 //in unencrypted connection
                 $wwwroot = str_replace("http://", "https://", $CFG->wwwroot);
             }
             echo '<div class="mdl_align"><p>' . get_string('paymentrequired') . '</p>';
             echo '<p><b>' . get_string('cost') . ": {$instance->currency} {$localisedcost}" . '</b></p>';
             echo '<p><a href="' . $wwwroot . '/login/">' . get_string('loginsite') . '</a></p>';
             echo "</div>";
         } else {
             $sql = "SELECT ud.data \n            FROM {user_info_data} ud \n            JOIN {user_info_field} uf ON uf.id = ud.fieldid\n            WHERE ud.userid = :userid AND uf.shortname = :fieldname";
             $params = array('userid' => $USER->id, 'fieldname' => 'Mobileno');
             $mob = $DB->get_field_sql($sql, $params);
             $coursefullname = format_string($course->fullname, true, array('context' => $context));
             $courseshortname = $shortname;
             $userfullname = fullname($USER);
             $userfirstname = $USER->firstname;
             $userlastname = $USER->lastname;
             $useremail = $USER->email;
             $userphonenumber = $USER->phone2;
             $instancename = $this->get_instance_name($instance);
             $businessname = $this->get_config('businessname');
             //get businessname from configuration
             $vendorid = $this->get_config('vendorid');
             $enrolperiod = $instance->enrolperiod;
             $curr = $this->get_config('currency');
             include $CFG->dirroot . '/enrol/ipay/enrol.html';
         }
     }
     return $OUTPUT->box(ob_get_clean());
 }

/**
 * Returns $user object of the main teacher for a course
 *
 * @uses $CFG
 * @param int $courseid The course in question.
 * @return user|false  A {@link $USER} record of the main teacher for the specified course or false if error.
 * @todo Finish documenting this function
 */
function get_teacher($courseid)
{
    global $CFG;
    $context = get_context_instance(CONTEXT_COURSE, $courseid);
    // Pass $view=true to filter hidden caps if the user cannot see them
    if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
        $users = sort_by_roleassignment_authority($users, $context);
        return array_shift($users);
    }
    return false;
}

 /**
  * Creates course enrol form, checks if form submitted
  * and enrols user if necessary. It can also redirect.
  *
  * @param stdClass $instance
  * @return string html text, usually a form in a text box
  */
 function enrol_page_hook(stdClass $instance)
 {
     global $CFG, $USER, $OUTPUT, $PAGE, $DB;
     ob_start();
     if ($DB->record_exists('user_enrolments', array('userid' => $USER->id, 'enrolid' => $instance->id))) {
         return ob_get_clean();
     }
     if ($instance->enrolstartdate != 0 && $instance->enrolstartdate > time()) {
         return ob_get_clean();
     }
     if ($instance->enrolenddate != 0 && $instance->enrolenddate < time()) {
         return ob_get_clean();
     }
     $course = $DB->get_record('course', array('id' => $instance->courseid));
     $strloginto = get_string("loginto", "", $course->shortname);
     $strcourses = get_string("courses");
     $context = get_context_instance(CONTEXT_COURSE, $course->id);
     // Pass $view=true to filter hidden caps if the user cannot see them
     if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
         $users = sort_by_roleassignment_authority($users, $context);
         $teacher = array_shift($users);
     } else {
         $teacher = false;
     }
     if ((double) $instance->cost <= 0) {
         $cost = (double) $this->get_config('cost');
     } else {
         $cost = (double) $instance->cost;
     }
     if (abs($cost) < 0.01) {
         // no cost, other enrolment methods (instances) should be used
         echo '<p>' . get_string('nocost', 'enrol_alipay') . '</p>';
     } else {
         if (isguestuser()) {
             // force login only for guest user, not real users with guest role
             if (empty($CFG->loginhttps)) {
                 $wwwroot = $CFG->wwwroot;
             } else {
                 // This actually is not so secure ;-), 'cause we're
                 // in unencrypted connection...
                 $wwwroot = str_replace("http://", "https://", $CFG->wwwroot);
             }
             echo '<div class="mdl-align"><p>' . get_string('paymentrequired') . '</p>';
             echo '<p><b>' . get_string('cost') . ": {$instance->currency} {$cost}" . '</b></p>';
             echo '<p><a href="' . $wwwroot . '/login/">' . get_string('loginsite') . '</a></p>';
             echo '</div>';
         } else {
             //Sanitise some fields before building the alipay form
             $coursefullname = format_string($course->fullname, true, array('context' => $context));
             $courseshortname = $course->shortname;
             $userfullname = fullname($USER);
             $userfirstname = $USER->firstname;
             $userlastname = $USER->lastname;
             $useraddress = $USER->address;
             $usercity = $USER->city;
             $instancename = $this->get_instance_name($instance);
             $data = $DB->get_record('enrol_alipay', array('courseid' => $instance->courseid, 'cost' => $cost, 'userid' => $USER->id, 'payment_status' => 0));
             if (!$data) {
                 $data = new stdClass();
                 $newinsert = true;
                 $timearr = gettimeofday();
                 $data->trade_no = date('YmdHis', $timearr['sec']) . intval(substr($timearr['usec'], 0, 3)) . '2';
                 //网站订单系统中的唯一订单号
                 $data->courseid = $instance->courseid;
                 $data->userid = $USER->id;
                 $data->cost = $instance->cost;
             }
             $data->seller_email = $this->get_config('alipaybusiness');
             $data->payment_status = 0;
             $data->timeupdated = time();
             if (isset($newinsert) && $newinsert) {
                 $DB->insert_record("enrol_alipay", $data);
             } else {
                 $DB->update_record("enrol_alipay", $data);
             }
             include $CFG->dirroot . '/enrol/alipay/build_form.php';
             include $CFG->dirroot . '/enrol/alipay/enrol.html';
         }
     }
     return $OUTPUT->box(ob_get_clean());
 }

function fetch_unassigned_users($minstoshowusers, $courseid, $context)
{
    global $CFG;
    $timetoshowusers = $minstoshowusers * 60;
    //Seconds default
    $timefrom = 100 * floor((time() - $timetoshowusers) / 100);
    // Round to nearest 100 seconds for better query cache
    $selectsql = "SELECT u.id, u.username, u.firstname, u.lastname, u.picture, max(ul.timeaccess) as lastaccess ";
    $from = "FROM {$CFG->prefix}user_lastaccess ul,\n                          {$CFG->prefix}user u ";
    $where = "WHERE ul.timeaccess > {$timefrom}\n                       AND u.id = ul.userid\n                       AND ul.courseid = {$courseid} \n\t\t\t\t\t   AND u.username not in \n\t\t\t\t\t   (SELECT p.username FROM {$CFG->prefix}poodllpairwork_usermap p WHERE p.course = {$courseid})\n\t\t\t\t\t\tAND u.username not in \n\t\t\t\t\t\t (SELECT p.partnername FROM {$CFG->prefix}poodllpairwork_usermap p WHERE p.course = {$courseid})";
    $order = "ORDER BY lastaccess DESC ";
    $groupby = "GROUP BY u.id, u.username, u.firstname, u.lastname, u.picture ";
    $SQL = $selectsql . $from . $where . $groupby . $order;
    $students = array();
    if ($users = get_records_sql($SQL)) {
        //this puts students first and if we end up with an odd number of students , we add a teacher.
        if (count($users) > 0) {
            //these throw errors when noone is online , but Ido not know a better way ..
            //we probably need to rewrite the sort function
            $students = sort_by_roleassignment_authority($users, $context, array(5));
            $nonstudents = sort_by_roleassignment_authority($users, $context, array(1, 2, 3, 4));
            if (count($students) % 2 > 0 && count($nonstudents) > 0) {
                $students[] = array_pop($nonstudents);
            }
        }
    }
    //We need to create pairs, so we return our students array, not the user array which contains all.
    return $students;
}

 /**
  * Send an email to the user when they are enroled.
  *
  * @param student $student The student object of for the enrolment.
  * @return bool Success/Failure.
  */
 public function newenrolmentemail(student $student)
 {
     global $DB;
     if (!empty($student->no_moodle_enrol)) {
         return false;
     }
     // Look for attached Moodle course, and get the course info.
     $moodlecourseid = moodle_get_course($student->classid);
     if (empty($moodlecourseid)) {
         return false;
     }
     $course = $DB->get_record('course', array('id' => $moodlecourseid));
     if (empty($course)) {
         return false;
     }
     // Get the elis user and the moodle user.
     $user = new user($student->userid);
     $muser = $user->get_moodleuser();
     if (empty($muser)) {
         return false;
     }
     // Check whether emails are enabled.
     $enabled = get_config('dhimport_version1elis', 'newenrolmentemailenabled');
     if (empty($enabled)) {
         return false;
     }
     // Check whether email text has been set.
     $template = get_config('dhimport_version1elis', 'newenrolmentemailtemplate');
     if (empty($template)) {
         return false;
     }
     // Ensure Moodle user has an email address.
     if (empty($muser->email)) {
         return false;
     }
     // Get the email subject line, set an empty string if necessary.
     $subject = get_config('dhimport_version1elis', 'newenrolmentemailsubject');
     if (empty($subject) || !is_string($subject)) {
         $subject = '';
     }
     // Get the user the email will be from.
     $from = get_config('dhimport_version1elis', 'newenrolmentemailfrom');
     if ($from === 'teacher') {
         $context = context_course::instance($course->id);
         $cap = 'moodle/course:update';
         if ($users = get_users_by_capability($context, $cap, 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
             $users = sort_by_roleassignment_authority($users, $context);
             $from = current($users);
         } else {
             $from = get_admin();
         }
     } else {
         $from = get_admin();
     }
     // Generate email.
     $body = $this->newenrolmentemail_generate($template, $muser, $course);
     // Send!
     return $this->sendemail($muser, $from, $subject, $body);
 }

 /**
  * Creates course enrol form, checks if form submitted
  * and enrols user if necessary. It can also redirect.
  *
  * @param stdClass $instance
  * @return string html text, usually a form in a text box
  */
 function enrol_page_hook(stdClass $instance)
 {
     global $CFG, $USER, $OUTPUT, $PAGE, $DB;
     ob_start();
     if ($DB->record_exists('user_enrolments', array('userid' => $USER->id, 'enrolid' => $instance->id))) {
         return ob_get_clean();
     }
     if ($instance->enrolstartdate != 0 && $instance->enrolstartdate > time()) {
         return ob_get_clean();
     }
     if ($instance->enrolenddate != 0 && $instance->enrolenddate < time()) {
         return ob_get_clean();
     }
     $course = $DB->get_record('course', array('id' => $instance->courseid));
     $strloginto = get_string("loginto", "", $course->shortname);
     $strcourses = get_string("courses");
     $context = get_context_instance(CONTEXT_COURSE, $course->id);
     // Pass $view=true to filter hidden caps if the user cannot see them
     if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
         $users = sort_by_roleassignment_authority($users, $context);
         $teacher = array_shift($users);
     } else {
         $teacher = false;
     }
     if ((double) $instance->cost <= 0) {
         $cost = (double) $this->get_config('cost');
     } else {
         $cost = (double) $instance->cost;
     }
     if ($instance->customint3 > 0) {
         // max enrol limit specified
         $count = $DB->count_records('user_enrolments', array('enrolid' => $instance->id));
         if ($count >= $instance->customint3) {
             // bad luck, no more enrolments here
             return $OUTPUT->notification(get_string('maxenrolledreached', 'enrol_globalclassroom'));
         }
     }
     print '<div class="mdl-align"><h5>' . $course->fullname . '</h5>' . $course->summary . '</div>';
     if (abs($cost) < 0.01 || $instance->customchar1 > 0 && $CFG->current_app->getCurrentUser()->isMember()) {
         require_once "{$CFG->dirroot}/enrol/globalclassroom/locallib.php";
         require_once "{$CFG->dirroot}/group/lib.php";
         $form = new enrol_globalclassroom_enrol_form(NULL, $instance);
         $instanceid = optional_param('instance', 0, PARAM_INT);
         if ($instance->password) {
             if ($instance->id == $instanceid) {
                 if ($data = $form->get_data()) {
                     $enrol = enrol_get_plugin('globalclassroom');
                     $CFG->current_app->enrolUserInCourse($course, $USER);
                     add_to_log($instance->courseid, 'course', 'enrol', '../enrol/users.php?id=' . $instance->courseid, $instance->courseid);
                     //there should be userid somewhere!
                     if ($instance->password and $instance->customint1 and $data->enrolpassword !== $instance->password) {
                         // it must be a group enrolment, let's assign group too
                         $groups = $DB->get_records('groups', array('courseid' => $instance->courseid), 'id', 'id, enrolmentkey');
                         foreach ($groups as $group) {
                             if (empty($group->enrolmentkey)) {
                                 continue;
                             }
                             if ($group->enrolmentkey === $data->enrolpassword) {
                                 groups_add_member($group->id, $USER->id);
                                 break;
                             }
                         }
                     }
                 }
             }
             $form->display();
         } else {
             $CFG->current_app->enrolUserInCourse($course, $USER);
             redirect($CFG->current_app->getAppUrl() . '/course/view.php?id=' . $course->id);
         }
     } else {
         if (isguestuser()) {
             // force login only for guest user, not real users with guest role
             if (empty($CFG->loginhttps)) {
                 $wwwroot = $CFG->wwwroot;
             } else {
                 // This actually is not so secure ;-), 'cause we're
                 // in unencrypted connection...
                 $wwwroot = str_replace("http://", "https://", $CFG->wwwroot);
             }
             echo '<div class="mdl-align"><p>' . get_string('paymentrequired') . '</p>';
             echo '<p><b>' . get_string('cost') . '$' . $cost . '</b></p>';
             echo '<p><a href="' . $wwwroot . '/login/">' . get_string('loginsite') . '</a></p>';
             echo '</div>';
         } else {
             //Sanitise some fields before building the PayPal form
             $coursefullname = format_string($course->fullname, true, array('context' => $context));
             $courseshortname = $course->shortname;
             $userfullname = fullname($USER);
             $userfirstname = $USER->firstname;
             $userlastname = $USER->lastname;
             $useraddress = $USER->address;
             $usercity = $USER->city;
//.........这里部分代码省略.........

 /**
  * Send an email to the user when they are enroled.
  *
  * @param int $user The user id being enroled.
  * @param int $course The course id they're being enroled into.
  * @return bool Success/Failure.
  */
 public function newenrolmentemail($userid, $courseid)
 {
     global $DB;
     if (empty($userid) || empty($courseid)) {
         return false;
     }
     $user = $DB->get_record('user', array('id' => $userid));
     $course = $DB->get_record('course', array('id' => $courseid));
     if (empty($user) || empty($course)) {
         return false;
     }
     $enabled = get_config('dhimport_version1', 'newenrolmentemailenabled');
     if (empty($enabled)) {
         // Emails disabled.
         return false;
     }
     $template = get_config('dhimport_version1', 'newenrolmentemailtemplate');
     if (empty($template)) {
         // No text set.
         return false;
     }
     if (empty($user->email)) {
         // User has no email.
         return false;
     }
     $subject = get_config('dhimport_version1', 'newenrolmentemailsubject');
     if (empty($subject) || !is_string($subject)) {
         $subject = '';
     }
     $from = get_config('dhimport_version1', 'newenrolmentemailfrom');
     if ($from === 'teacher') {
         $context = context_course::instance($courseid);
         if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC', '', '', '', '', false, true)) {
             $users = sort_by_roleassignment_authority($users, $context);
             $from = current($users);
         } else {
             $from = get_admin();
         }
     } else {
         $from = get_admin();
     }
     $body = $this->newenrolmentemail_generate($template, $user, $course);
     return $this->sendemail($user, $from, $subject, $body);
 }