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See Release Notes

  • Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
  • Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
  • PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.
/lib/ -> enrollib.php (source)

Differences Between: [Versions 310 and 311] [Versions 311 and 400] [Versions 311 and 401] [Versions 38 and 311] [Versions 39 and 311]

   1  <?php
   2  
   3  // This file is part of Moodle - http://moodle.org/
   4  //
   5  // Moodle is free software: you can redistribute it and/or modify
   6  // it under the terms of the GNU General Public License as published by
   7  // the Free Software Foundation, either version 3 of the License, or
   8  // (at your option) any later version.
   9  //
  10  // Moodle is distributed in the hope that it will be useful,
  11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  // GNU General Public License for more details.
  14  //
  15  // You should have received a copy of the GNU General Public License
  16  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17  
  18  /**
  19   * This library includes the basic parts of enrol api.
  20   * It is available on each page.
  21   *
  22   * @package    core
  23   * @subpackage enrol
  24   * @copyright  2010 Petr Skoda {@link http://skodak.org}
  25   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26   */
  27  
  28  defined('MOODLE_INTERNAL') || die();
  29  
  30  /** Course enrol instance enabled. (used in enrol->status) */
  31  define('ENROL_INSTANCE_ENABLED', 0);
  32  
  33  /** Course enrol instance disabled, user may enter course if other enrol instance enabled. (used in enrol->status)*/
  34  define('ENROL_INSTANCE_DISABLED', 1);
  35  
  36  /** User is active participant (used in user_enrolments->status)*/
  37  define('ENROL_USER_ACTIVE', 0);
  38  
  39  /** User participation in course is suspended (used in user_enrolments->status) */
  40  define('ENROL_USER_SUSPENDED', 1);
  41  
  42  /** @deprecated - enrol caching was reworked, use ENROL_MAX_TIMESTAMP instead */
  43  define('ENROL_REQUIRE_LOGIN_CACHE_PERIOD', 1800);
  44  
  45  /** The timestamp indicating forever */
  46  define('ENROL_MAX_TIMESTAMP', 2147483647);
  47  
  48  /** When user disappears from external source, the enrolment is completely removed */
  49  define('ENROL_EXT_REMOVED_UNENROL', 0);
  50  
  51  /** When user disappears from external source, the enrolment is kept as is - one way sync */
  52  define('ENROL_EXT_REMOVED_KEEP', 1);
  53  
  54  /** @deprecated since 2.4 not used any more, migrate plugin to new restore methods */
  55  define('ENROL_RESTORE_TYPE', 'enrolrestore');
  56  
  57  /**
  58   * When user disappears from external source, user enrolment is suspended, roles are kept as is.
  59   * In some cases user needs a role with some capability to be visible in UI - suc has in gradebook,
  60   * assignments, etc.
  61   */
  62  define('ENROL_EXT_REMOVED_SUSPEND', 2);
  63  
  64  /**
  65   * When user disappears from external source, the enrolment is suspended and roles assigned
  66   * by enrol instance are removed. Please note that user may "disappear" from gradebook and other areas.
  67   * */
  68  define('ENROL_EXT_REMOVED_SUSPENDNOROLES', 3);
  69  
  70  /**
  71   * Do not send email.
  72   */
  73  define('ENROL_DO_NOT_SEND_EMAIL', 0);
  74  
  75  /**
  76   * Send email from course contact.
  77   */
  78  define('ENROL_SEND_EMAIL_FROM_COURSE_CONTACT', 1);
  79  
  80  /**
  81   * Send email from enrolment key holder.
  82   */
  83  define('ENROL_SEND_EMAIL_FROM_KEY_HOLDER', 2);
  84  
  85  /**
  86   * Send email from no reply address.
  87   */
  88  define('ENROL_SEND_EMAIL_FROM_NOREPLY', 3);
  89  
  90  /** Edit enrolment action. */
  91  define('ENROL_ACTION_EDIT', 'editenrolment');
  92  
  93  /** Unenrol action. */
  94  define('ENROL_ACTION_UNENROL', 'unenrol');
  95  
  96  /**
  97   * Returns instances of enrol plugins
  98   * @param bool $enabled return enabled only
  99   * @return array of enrol plugins name=>instance
 100   */
 101  function enrol_get_plugins($enabled) {
 102      global $CFG;
 103  
 104      $result = array();
 105  
 106      if ($enabled) {
 107          // sorted by enabled plugin order
 108          $enabled = explode(',', $CFG->enrol_plugins_enabled);
 109          $plugins = array();
 110          foreach ($enabled as $plugin) {
 111              $plugins[$plugin] = "$CFG->dirroot/enrol/$plugin";
 112          }
 113      } else {
 114          // sorted alphabetically
 115          $plugins = core_component::get_plugin_list('enrol');
 116          ksort($plugins);
 117      }
 118  
 119      foreach ($plugins as $plugin=>$location) {
 120          $class = "enrol_{$plugin}_plugin";
 121          if (!class_exists($class)) {
 122              if (!file_exists("$location/lib.php")) {
 123                  continue;
 124              }
 125              include_once("$location/lib.php");
 126              if (!class_exists($class)) {
 127                  continue;
 128              }
 129          }
 130  
 131          $result[$plugin] = new $class();
 132      }
 133  
 134      return $result;
 135  }
 136  
 137  /**
 138   * Returns instance of enrol plugin
 139   * @param  string $name name of enrol plugin ('manual', 'guest', ...)
 140   * @return enrol_plugin
 141   */
 142  function enrol_get_plugin($name) {
 143      global $CFG;
 144  
 145      $name = clean_param($name, PARAM_PLUGIN);
 146  
 147      if (empty($name)) {
 148          // ignore malformed or missing plugin names completely
 149          return null;
 150      }
 151  
 152      $location = "$CFG->dirroot/enrol/$name";
 153  
 154      $class = "enrol_{$name}_plugin";
 155      if (!class_exists($class)) {
 156          if (!file_exists("$location/lib.php")) {
 157              return null;
 158          }
 159          include_once("$location/lib.php");
 160          if (!class_exists($class)) {
 161              return null;
 162          }
 163      }
 164  
 165      return new $class();
 166  }
 167  
 168  /**
 169   * Returns enrolment instances in given course.
 170   * @param int $courseid
 171   * @param bool $enabled
 172   * @return array of enrol instances
 173   */
 174  function enrol_get_instances($courseid, $enabled) {
 175      global $DB, $CFG;
 176  
 177      if (!$enabled) {
 178          return $DB->get_records('enrol', array('courseid'=>$courseid), 'sortorder,id');
 179      }
 180  
 181      $result = $DB->get_records('enrol', array('courseid'=>$courseid, 'status'=>ENROL_INSTANCE_ENABLED), 'sortorder,id');
 182  
 183      $enabled = explode(',', $CFG->enrol_plugins_enabled);
 184      foreach ($result as $key=>$instance) {
 185          if (!in_array($instance->enrol, $enabled)) {
 186              unset($result[$key]);
 187              continue;
 188          }
 189          if (!file_exists("$CFG->dirroot/enrol/$instance->enrol/lib.php")) {
 190              // broken plugin
 191              unset($result[$key]);
 192              continue;
 193          }
 194      }
 195  
 196      return $result;
 197  }
 198  
 199  /**
 200   * Checks if a given plugin is in the list of enabled enrolment plugins.
 201   *
 202   * @param string $enrol Enrolment plugin name
 203   * @return boolean Whether the plugin is enabled
 204   */
 205  function enrol_is_enabled($enrol) {
 206      global $CFG;
 207  
 208      if (empty($CFG->enrol_plugins_enabled)) {
 209          return false;
 210      }
 211      return in_array($enrol, explode(',', $CFG->enrol_plugins_enabled));
 212  }
 213  
 214  /**
 215   * Check all the login enrolment information for the given user object
 216   * by querying the enrolment plugins
 217   *
 218   * This function may be very slow, use only once after log-in or login-as.
 219   *
 220   * @param stdClass $user
 221   * @return void
 222   */
 223  function enrol_check_plugins($user) {
 224      global $CFG;
 225  
 226      if (empty($user->id) or isguestuser($user)) {
 227          // shortcut - there is no enrolment work for guests and not-logged-in users
 228          return;
 229      }
 230  
 231      // originally there was a broken admin test, but accidentally it was non-functional in 2.2,
 232      // which proved it was actually not necessary.
 233  
 234      static $inprogress = array();  // To prevent this function being called more than once in an invocation
 235  
 236      if (!empty($inprogress[$user->id])) {
 237          return;
 238      }
 239  
 240      $inprogress[$user->id] = true;  // Set the flag
 241  
 242      $enabled = enrol_get_plugins(true);
 243  
 244      foreach($enabled as $enrol) {
 245          $enrol->sync_user_enrolments($user);
 246      }
 247  
 248      unset($inprogress[$user->id]);  // Unset the flag
 249  }
 250  
 251  /**
 252   * Do these two students share any course?
 253   *
 254   * The courses has to be visible and enrolments has to be active,
 255   * timestart and timeend restrictions are ignored.
 256   *
 257   * This function calls {@see enrol_get_shared_courses()} setting checkexistsonly
 258   * to true.
 259   *
 260   * @param stdClass|int $user1
 261   * @param stdClass|int $user2
 262   * @return bool
 263   */
 264  function enrol_sharing_course($user1, $user2) {
 265      return enrol_get_shared_courses($user1, $user2, false, true);
 266  }
 267  
 268  /**
 269   * Returns any courses shared by the two users
 270   *
 271   * The courses has to be visible and enrolments has to be active,
 272   * timestart and timeend restrictions are ignored.
 273   *
 274   * @global moodle_database $DB
 275   * @param stdClass|int $user1
 276   * @param stdClass|int $user2
 277   * @param bool $preloadcontexts If set to true contexts for the returned courses
 278   *              will be preloaded.
 279   * @param bool $checkexistsonly If set to true then this function will return true
 280   *              if the users share any courses and false if not.
 281   * @return array|bool An array of courses that both users are enrolled in OR if
 282   *              $checkexistsonly set returns true if the users share any courses
 283   *              and false if not.
 284   */
 285  function enrol_get_shared_courses($user1, $user2, $preloadcontexts = false, $checkexistsonly = false) {
 286      global $DB, $CFG;
 287  
 288      $user1 = isset($user1->id) ? $user1->id : $user1;
 289      $user2 = isset($user2->id) ? $user2->id : $user2;
 290  
 291      if (empty($user1) or empty($user2)) {
 292          return false;
 293      }
 294  
 295      if (!$plugins = explode(',', $CFG->enrol_plugins_enabled)) {
 296          return false;
 297      }
 298  
 299      list($plugins1, $params1) = $DB->get_in_or_equal($plugins, SQL_PARAMS_NAMED, 'ee1');
 300      list($plugins2, $params2) = $DB->get_in_or_equal($plugins, SQL_PARAMS_NAMED, 'ee2');
 301      $params = array_merge($params1, $params2);
 302      $params['enabled1'] = ENROL_INSTANCE_ENABLED;
 303      $params['enabled2'] = ENROL_INSTANCE_ENABLED;
 304      $params['active1'] = ENROL_USER_ACTIVE;
 305      $params['active2'] = ENROL_USER_ACTIVE;
 306      $params['user1']   = $user1;
 307      $params['user2']   = $user2;
 308  
 309      $ctxselect = '';
 310      $ctxjoin = '';
 311      if ($preloadcontexts) {
 312          $ctxselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
 313          $ctxjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
 314          $params['contextlevel'] = CONTEXT_COURSE;
 315      }
 316  
 317      $sql = "SELECT c.* $ctxselect
 318                FROM {course} c
 319                JOIN (
 320                  SELECT DISTINCT c.id
 321                    FROM {course} c
 322                    JOIN {enrol} e1 ON (c.id = e1.courseid AND e1.status = :enabled1 AND e1.enrol $plugins1)
 323                    JOIN {user_enrolments} ue1 ON (ue1.enrolid = e1.id AND ue1.status = :active1 AND ue1.userid = :user1)
 324                    JOIN {enrol} e2 ON (c.id = e2.courseid AND e2.status = :enabled2 AND e2.enrol $plugins2)
 325                    JOIN {user_enrolments} ue2 ON (ue2.enrolid = e2.id AND ue2.status = :active2 AND ue2.userid = :user2)
 326                   WHERE c.visible = 1
 327                ) ec ON ec.id = c.id
 328                $ctxjoin";
 329  
 330      if ($checkexistsonly) {
 331          return $DB->record_exists_sql($sql, $params);
 332      } else {
 333          $courses = $DB->get_records_sql($sql, $params);
 334          if ($preloadcontexts) {
 335              array_map('context_helper::preload_from_record', $courses);
 336          }
 337          return $courses;
 338      }
 339  }
 340  
 341  /**
 342   * This function adds necessary enrol plugins UI into the course edit form.
 343   *
 344   * @param MoodleQuickForm $mform
 345   * @param object $data course edit form data
 346   * @param object $context context of existing course or parent category if course does not exist
 347   * @return void
 348   */
 349  function enrol_course_edit_form(MoodleQuickForm $mform, $data, $context) {
 350      $plugins = enrol_get_plugins(true);
 351      if (!empty($data->id)) {
 352          $instances = enrol_get_instances($data->id, false);
 353          foreach ($instances as $instance) {
 354              if (!isset($plugins[$instance->enrol])) {
 355                  continue;
 356              }
 357              $plugin = $plugins[$instance->enrol];
 358              $plugin->course_edit_form($instance, $mform, $data, $context);
 359          }
 360      } else {
 361          foreach ($plugins as $plugin) {
 362              $plugin->course_edit_form(NULL, $mform, $data, $context);
 363          }
 364      }
 365  }
 366  
 367  /**
 368   * Validate course edit form data
 369   *
 370   * @param array $data raw form data
 371   * @param object $context context of existing course or parent category if course does not exist
 372   * @return array errors array
 373   */
 374  function enrol_course_edit_validation(array $data, $context) {
 375      $errors = array();
 376      $plugins = enrol_get_plugins(true);
 377  
 378      if (!empty($data['id'])) {
 379          $instances = enrol_get_instances($data['id'], false);
 380          foreach ($instances as $instance) {
 381              if (!isset($plugins[$instance->enrol])) {
 382                  continue;
 383              }
 384              $plugin = $plugins[$instance->enrol];
 385              $errors = array_merge($errors, $plugin->course_edit_validation($instance, $data, $context));
 386          }
 387      } else {
 388          foreach ($plugins as $plugin) {
 389              $errors = array_merge($errors, $plugin->course_edit_validation(NULL, $data, $context));
 390          }
 391      }
 392  
 393      return $errors;
 394  }
 395  
 396  /**
 397   * Update enrol instances after course edit form submission
 398   * @param bool $inserted true means new course added, false course already existed
 399   * @param object $course
 400   * @param object $data form data
 401   * @return void
 402   */
 403  function enrol_course_updated($inserted, $course, $data) {
 404      global $DB, $CFG;
 405  
 406      $plugins = enrol_get_plugins(true);
 407  
 408      foreach ($plugins as $plugin) {
 409          $plugin->course_updated($inserted, $course, $data);
 410      }
 411  }
 412  
 413  /**
 414   * Add navigation nodes
 415   * @param navigation_node $coursenode
 416   * @param object $course
 417   * @return void
 418   */
 419  function enrol_add_course_navigation(navigation_node $coursenode, $course) {
 420      global $CFG;
 421  
 422      $coursecontext = context_course::instance($course->id);
 423  
 424      $instances = enrol_get_instances($course->id, true);
 425      $plugins   = enrol_get_plugins(true);
 426  
 427      // we do not want to break all course pages if there is some borked enrol plugin, right?
 428      foreach ($instances as $k=>$instance) {
 429          if (!isset($plugins[$instance->enrol])) {
 430              unset($instances[$k]);
 431          }
 432      }
 433  
 434      $usersnode = $coursenode->add(get_string('users'), null, navigation_node::TYPE_CONTAINER, null, 'users');
 435  
 436      if ($course->id != SITEID) {
 437          // list all participants - allows assigning roles, groups, etc.
 438          if (has_capability('moodle/course:enrolreview', $coursecontext)) {
 439              $url = new moodle_url('/user/index.php', array('id'=>$course->id));
 440              $usersnode->add(get_string('enrolledusers', 'enrol'), $url, navigation_node::TYPE_SETTING, null, 'review', new pix_icon('i/enrolusers', ''));
 441          }
 442  
 443          // manage enrol plugin instances
 444          if (has_capability('moodle/course:enrolconfig', $coursecontext) or has_capability('moodle/course:enrolreview', $coursecontext)) {
 445              $url = new moodle_url('/enrol/instances.php', array('id'=>$course->id));
 446          } else {
 447              $url = NULL;
 448          }
 449          $instancesnode = $usersnode->add(get_string('enrolmentinstances', 'enrol'), $url, navigation_node::TYPE_SETTING, null, 'manageinstances');
 450  
 451          // each instance decides how to configure itself or how many other nav items are exposed
 452          foreach ($instances as $instance) {
 453              if (!isset($plugins[$instance->enrol])) {
 454                  continue;
 455              }
 456              $plugins[$instance->enrol]->add_course_navigation($instancesnode, $instance);
 457          }
 458  
 459          if (!$url) {
 460              $instancesnode->trim_if_empty();
 461          }
 462      }
 463  
 464      // Manage groups in this course or even frontpage
 465      if (($course->groupmode || !$course->groupmodeforce) && has_capability('moodle/course:managegroups', $coursecontext)) {
 466          $url = new moodle_url('/group/index.php', array('id'=>$course->id));
 467          $usersnode->add(get_string('groups'), $url, navigation_node::TYPE_SETTING, null, 'groups', new pix_icon('i/group', ''));
 468      }
 469  
 470       if (has_any_capability(array( 'moodle/role:assign', 'moodle/role:safeoverride','moodle/role:override', 'moodle/role:review'), $coursecontext)) {
 471          // Override roles
 472          if (has_capability('moodle/role:review', $coursecontext)) {
 473              $url = new moodle_url('/admin/roles/permissions.php', array('contextid'=>$coursecontext->id));
 474          } else {
 475              $url = NULL;
 476          }
 477          $permissionsnode = $usersnode->add(get_string('permissions', 'role'), $url, navigation_node::TYPE_SETTING, null, 'override');
 478  
 479          // Add assign or override roles if allowed
 480          if ($course->id == SITEID or (!empty($CFG->adminsassignrolesincourse) and is_siteadmin())) {
 481              if (has_capability('moodle/role:assign', $coursecontext)) {
 482                  $url = new moodle_url('/admin/roles/assign.php', array('contextid'=>$coursecontext->id));
 483                  $permissionsnode->add(get_string('assignedroles', 'role'), $url, navigation_node::TYPE_SETTING, null, 'roles', new pix_icon('i/assignroles', ''));
 484              }
 485          }
 486          // Check role permissions
 487          if (has_any_capability(array('moodle/role:assign', 'moodle/role:safeoverride', 'moodle/role:override'), $coursecontext)) {
 488              $url = new moodle_url('/admin/roles/check.php', array('contextid'=>$coursecontext->id));
 489              $permissionsnode->add(get_string('checkpermissions', 'role'), $url, navigation_node::TYPE_SETTING, null, 'permissions', new pix_icon('i/checkpermissions', ''));
 490          }
 491       }
 492  
 493       // Deal somehow with users that are not enrolled but still got a role somehow
 494      if ($course->id != SITEID) {
 495          //TODO, create some new UI for role assignments at course level
 496          if (has_capability('moodle/course:reviewotherusers', $coursecontext)) {
 497              $url = new moodle_url('/enrol/otherusers.php', array('id'=>$course->id));
 498              $usersnode->add(get_string('notenrolledusers', 'enrol'), $url, navigation_node::TYPE_SETTING, null, 'otherusers', new pix_icon('i/assignroles', ''));
 499          }
 500      }
 501  
 502      // just in case nothing was actually added
 503      $usersnode->trim_if_empty();
 504  
 505      if ($course->id != SITEID) {
 506          if (isguestuser() or !isloggedin()) {
 507              // guest account can not be enrolled - no links for them
 508          } else if (is_enrolled($coursecontext)) {
 509              // unenrol link if possible
 510              foreach ($instances as $instance) {
 511                  if (!isset($plugins[$instance->enrol])) {
 512                      continue;
 513                  }
 514                  $plugin = $plugins[$instance->enrol];
 515                  if ($unenrollink = $plugin->get_unenrolself_link($instance)) {
 516                      $shortname = format_string($course->shortname, true, array('context' => $coursecontext));
 517                      $coursenode->add(get_string('unenrolme', 'core_enrol', $shortname), $unenrollink, navigation_node::TYPE_SETTING, null, 'unenrolself', new pix_icon('i/user', ''));
 518                      break;
 519                      //TODO. deal with multiple unenrol links - not likely case, but still...
 520                  }
 521              }
 522          } else {
 523              // enrol link if possible
 524              if (is_viewing($coursecontext)) {
 525                  // better not show any enrol link, this is intended for managers and inspectors
 526              } else {
 527                  foreach ($instances as $instance) {
 528                      if (!isset($plugins[$instance->enrol])) {
 529                          continue;
 530                      }
 531                      $plugin = $plugins[$instance->enrol];
 532                      if ($plugin->show_enrolme_link($instance)) {
 533                          $url = new moodle_url('/enrol/index.php', array('id'=>$course->id));
 534                          $shortname = format_string($course->shortname, true, array('context' => $coursecontext));
 535                          $coursenode->add(get_string('enrolme', 'core_enrol', $shortname), $url, navigation_node::TYPE_SETTING, null, 'enrolself', new pix_icon('i/user', ''));
 536                          break;
 537                      }
 538                  }
 539              }
 540          }
 541      }
 542  }
 543  
 544  /**
 545   * Returns list of courses current $USER is enrolled in and can access
 546   *
 547   * The $fields param is a list of field names to ADD so name just the fields you really need,
 548   * which will be added and uniq'd.
 549   *
 550   * If $allaccessible is true, this will additionally return courses that the current user is not
 551   * enrolled in, but can access because they are open to the user for other reasons (course view
 552   * permission, currently viewing course as a guest, or course allows guest access without
 553   * password).
 554   *
 555   * @param string|array $fields Extra fields to be returned (array or comma-separated list).
 556   * @param string|null $sort Comma separated list of fields to sort by, defaults to respecting navsortmycoursessort.
 557   * Allowed prefixes for sort fields are: "ul" for the user_lastaccess table, "c" for the courses table,
 558   * "ue" for the user_enrolments table.
 559   * @param int $limit max number of courses
 560   * @param array $courseids the list of course ids to filter by
 561   * @param bool $allaccessible Include courses user is not enrolled in, but can access
 562   * @param int $offset Offset the result set by this number
 563   * @param array $excludecourses IDs of hidden courses to exclude from search
 564   * @return array
 565   */
 566  function enrol_get_my_courses($fields = null, $sort = null, $limit = 0, $courseids = [], $allaccessible = false,
 567      $offset = 0, $excludecourses = []) {
 568      global $DB, $USER, $CFG;
 569  
 570      // Allowed prefixes and field names.
 571      $allowedprefixesandfields = ['c' => array_keys($DB->get_columns('course')),
 572                                  'ul' => array_keys($DB->get_columns('user_lastaccess')),
 573                                  'ue' => array_keys($DB->get_columns('user_enrolments'))];
 574  
 575      // Re-Arrange the course sorting according to the admin settings.
 576      $sort = enrol_get_courses_sortingsql($sort);
 577  
 578      // Guest account does not have any enrolled courses.
 579      if (!$allaccessible && (isguestuser() or !isloggedin())) {
 580          return array();
 581      }
 582  
 583      $basefields = [
 584          'id', 'category', 'sortorder',
 585          'shortname', 'fullname', 'idnumber',
 586          'startdate', 'visible',
 587          'groupmode', 'groupmodeforce', 'cacherev',
 588          'showactivitydates', 'showcompletionconditions',
 589      ];
 590  
 591      if (empty($fields)) {
 592          $fields = $basefields;
 593      } else if (is_string($fields)) {
 594          // turn the fields from a string to an array
 595          $fields = explode(',', $fields);
 596          $fields = array_map('trim', $fields);
 597          $fields = array_unique(array_merge($basefields, $fields));
 598      } else if (is_array($fields)) {
 599          $fields = array_unique(array_merge($basefields, $fields));
 600      } else {
 601          throw new coding_exception('Invalid $fields parameter in enrol_get_my_courses()');
 602      }
 603      if (in_array('*', $fields)) {
 604          $fields = array('*');
 605      }
 606  
 607      $orderby = "";
 608      $sort    = trim($sort);
 609      $sorttimeaccess = false;
 610      if (!empty($sort)) {
 611          $rawsorts = explode(',', $sort);
 612          $sorts = array();
 613          foreach ($rawsorts as $rawsort) {
 614              $rawsort = trim($rawsort);
 615              // Make sure that there are no more white spaces in sortparams after explode.
 616              $sortparams = array_values(array_filter(explode(' ', $rawsort)));
 617              // If more than 2 values present then throw coding_exception.
 618              if (isset($sortparams[2])) {
 619                  throw new coding_exception('Invalid $sort parameter in enrol_get_my_courses()');
 620              }
 621              // Check the sort ordering if present, at the beginning.
 622              if (isset($sortparams[1]) && (preg_match("/^(asc|desc)$/i", $sortparams[1]) === 0)) {
 623                  throw new coding_exception('Invalid sort direction in $sort parameter in enrol_get_my_courses()');
 624              }
 625  
 626              $sortfield = $sortparams[0];
 627              $sortdirection = $sortparams[1] ?? 'asc';
 628              if (strpos($sortfield, '.') !== false) {
 629                  $sortfieldparams = explode('.', $sortfield);
 630                  // Check if more than one dots present in the prefix field.
 631                  if (isset($sortfieldparams[2])) {
 632                      throw new coding_exception('Invalid $sort parameter in enrol_get_my_courses()');
 633                  }
 634                  list($prefix, $fieldname) = [$sortfieldparams[0], $sortfieldparams[1]];
 635                  // Check if the field name matches with the allowed prefix.
 636                  if (array_key_exists($prefix, $allowedprefixesandfields) &&
 637                      (in_array($fieldname, $allowedprefixesandfields[$prefix]))) {
 638                      if ($prefix === 'ul') {
 639                          $sorts[] = "COALESCE({$prefix}.{$fieldname}, 0) {$sortdirection}";
 640                          $sorttimeaccess = true;
 641                      } else {
 642                          // Check if the field name that matches with the prefix and just append to sorts.
 643                          $sorts[] = $rawsort;
 644                      }
 645                  } else {
 646                      throw new coding_exception('Invalid $sort parameter in enrol_get_my_courses()');
 647                  }
 648              } else {
 649                  // Check if the field name matches with $allowedprefixesandfields.
 650                  $found = false;
 651                  foreach (array_keys($allowedprefixesandfields) as $prefix) {
 652                      if (in_array($sortfield, $allowedprefixesandfields[$prefix])) {
 653                          if ($prefix === 'ul') {
 654                              $sorts[] = "COALESCE({$prefix}.{$sortfield}, 0) {$sortdirection}";
 655                              $sorttimeaccess = true;
 656                          } else {
 657                              $sorts[] = "{$prefix}.{$sortfield} {$sortdirection}";
 658                          }
 659                          $found = true;
 660                          break;
 661                      }
 662                  }
 663                  if (!$found) {
 664                      // The param is not found in $allowedprefixesandfields.
 665                      throw new coding_exception('Invalid $sort parameter in enrol_get_my_courses()');
 666                  }
 667              }
 668          }
 669          $sort = implode(',', $sorts);
 670          $orderby = "ORDER BY $sort";
 671      }
 672  
 673      $wheres = ['c.id <> ' . SITEID];
 674      $params = [];
 675  
 676      if (isset($USER->loginascontext) and $USER->loginascontext->contextlevel == CONTEXT_COURSE) {
 677          // list _only_ this course - anything else is asking for trouble...
 678          $wheres[] = "courseid = :loginas";
 679          $params['loginas'] = $USER->loginascontext->instanceid;
 680      }
 681  
 682      $coursefields = 'c.' .join(',c.', $fields);
 683      $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
 684      $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
 685      $params['contextlevel'] = CONTEXT_COURSE;
 686      $wheres = implode(" AND ", $wheres);
 687  
 688      $timeaccessselect = "";
 689      $timeaccessjoin = "";
 690  
 691      if (!empty($courseids)) {
 692          list($courseidssql, $courseidsparams) = $DB->get_in_or_equal($courseids, SQL_PARAMS_NAMED);
 693          $wheres = sprintf("%s AND c.id %s", $wheres, $courseidssql);
 694          $params = array_merge($params, $courseidsparams);
 695      }
 696  
 697      if (!empty($excludecourses)) {
 698          list($courseidssql, $courseidsparams) = $DB->get_in_or_equal($excludecourses, SQL_PARAMS_NAMED, 'param', false);
 699          $wheres = sprintf("%s AND c.id %s", $wheres, $courseidssql);
 700          $params = array_merge($params, $courseidsparams);
 701      }
 702  
 703      $courseidsql = "";
 704      // Logged-in, non-guest users get their enrolled courses.
 705      if (!isguestuser() && isloggedin()) {
 706          $courseidsql .= "
 707                  SELECT DISTINCT e.courseid
 708                    FROM {enrol} e
 709                    JOIN {user_enrolments} ue ON (ue.enrolid = e.id AND ue.userid = :userid1)
 710                   WHERE ue.status = :active AND e.status = :enabled AND ue.timestart <= :now1
 711                         AND (ue.timeend = 0 OR ue.timeend > :now2)";
 712          $params['userid1'] = $USER->id;
 713          $params['active'] = ENROL_USER_ACTIVE;
 714          $params['enabled'] = ENROL_INSTANCE_ENABLED;
 715          $params['now1'] = $params['now2'] = time();
 716  
 717          if ($sorttimeaccess) {
 718              $params['userid2'] = $USER->id;
 719              $timeaccessselect = ', ul.timeaccess as lastaccessed';
 720              $timeaccessjoin = "LEFT JOIN {user_lastaccess} ul ON (ul.courseid = c.id AND ul.userid = :userid2)";
 721          }
 722      }
 723  
 724      // When including non-enrolled but accessible courses...
 725      if ($allaccessible) {
 726          if (is_siteadmin()) {
 727              // Site admins can access all courses.
 728              $courseidsql = "SELECT DISTINCT c2.id AS courseid FROM {course} c2";
 729          } else {
 730              // If we used the enrolment as well, then this will be UNIONed.
 731              if ($courseidsql) {
 732                  $courseidsql .= " UNION ";
 733              }
 734  
 735              // Include courses with guest access and no password.
 736              $courseidsql .= "
 737                      SELECT DISTINCT e.courseid
 738                        FROM {enrol} e
 739                       WHERE e.enrol = 'guest' AND e.password = :emptypass AND e.status = :enabled2";
 740              $params['emptypass'] = '';
 741              $params['enabled2'] = ENROL_INSTANCE_ENABLED;
 742  
 743              // Include courses where the current user is currently using guest access (may include
 744              // those which require a password).
 745              $courseids = [];
 746              $accessdata = get_user_accessdata($USER->id);
 747              foreach ($accessdata['ra'] as $contextpath => $roles) {
 748                  if (array_key_exists($CFG->guestroleid, $roles)) {
 749                      // Work out the course id from context path.
 750                      $context = context::instance_by_id(preg_replace('~^.*/~', '', $contextpath));
 751                      if ($context instanceof context_course) {
 752                          $courseids[$context->instanceid] = true;
 753                      }
 754                  }
 755              }
 756  
 757              // Include courses where the current user has moodle/course:view capability.
 758              $courses = get_user_capability_course('moodle/course:view', null, false);
 759              if (!$courses) {
 760                  $courses = [];
 761              }
 762              foreach ($courses as $course) {
 763                  $courseids[$course->id] = true;
 764              }
 765  
 766              // If there are any in either category, list them individually.
 767              if ($courseids) {
 768                  list ($allowedsql, $allowedparams) = $DB->get_in_or_equal(
 769                          array_keys($courseids), SQL_PARAMS_NAMED);
 770                  $courseidsql .= "
 771                          UNION
 772                         SELECT DISTINCT c3.id AS courseid
 773                           FROM {course} c3
 774                          WHERE c3.id $allowedsql";
 775                  $params = array_merge($params, $allowedparams);
 776              }
 777          }
 778      }
 779  
 780      // Note: we can not use DISTINCT + text fields due to Oracle and MS limitations, that is why
 781      // we have the subselect there.
 782      $sql = "SELECT $coursefields $ccselect $timeaccessselect
 783                FROM {course} c
 784                JOIN ($courseidsql) en ON (en.courseid = c.id)
 785             $timeaccessjoin
 786             $ccjoin
 787               WHERE $wheres
 788            $orderby";
 789  
 790      $courses = $DB->get_records_sql($sql, $params, $offset, $limit);
 791  
 792      // preload contexts and check visibility
 793      foreach ($courses as $id=>$course) {
 794          context_helper::preload_from_record($course);
 795          if (!$course->visible) {
 796              if (!$context = context_course::instance($id, IGNORE_MISSING)) {
 797                  unset($courses[$id]);
 798                  continue;
 799              }
 800              if (!has_capability('moodle/course:viewhiddencourses', $context)) {
 801                  unset($courses[$id]);
 802                  continue;
 803              }
 804          }
 805          $courses[$id] = $course;
 806      }
 807  
 808      //wow! Is that really all? :-D
 809  
 810      return $courses;
 811  }
 812  
 813  /**
 814   * Returns course enrolment information icons.
 815   *
 816   * @param object $course
 817   * @param array $instances enrol instances of this course, improves performance
 818   * @return array of pix_icon
 819   */
 820  function enrol_get_course_info_icons($course, array $instances = NULL) {
 821      $icons = array();
 822      if (is_null($instances)) {
 823          $instances = enrol_get_instances($course->id, true);
 824      }
 825      $plugins = enrol_get_plugins(true);
 826      foreach ($plugins as $name => $plugin) {
 827          $pis = array();
 828          foreach ($instances as $instance) {
 829              if ($instance->status != ENROL_INSTANCE_ENABLED or $instance->courseid != $course->id) {
 830                  debugging('Invalid instances parameter submitted in enrol_get_info_icons()');
 831                  continue;
 832              }
 833              if ($instance->enrol == $name) {
 834                  $pis[$instance->id] = $instance;
 835              }
 836          }
 837          if ($pis) {
 838              $icons = array_merge($icons, $plugin->get_info_icons($pis));
 839          }
 840      }
 841      return $icons;
 842  }
 843  
 844  /**
 845   * Returns SQL ORDER arguments which reflect the admin settings to sort my courses.
 846   *
 847   * @param string|null $sort SQL ORDER arguments which were originally requested (optionally).
 848   * @return string SQL ORDER arguments.
 849   */
 850  function enrol_get_courses_sortingsql($sort = null) {
 851      global $CFG;
 852  
 853      // Prepare the visible SQL fragment as empty.
 854      $visible = '';
 855      // Only create a visible SQL fragment if the caller didn't already pass a sort order which contains the visible field.
 856      if ($sort === null || strpos($sort, 'visible') === false) {
 857          // If the admin did not explicitly want to have shown and hidden courses sorted as one list, we will sort hidden
 858          // courses to the end of the course list.
 859          if (!isset($CFG->navsortmycourseshiddenlast) || $CFG->navsortmycourseshiddenlast == true) {
 860              $visible = 'visible DESC, ';
 861          }
 862      }
 863  
 864      // Only create a sortorder SQL fragment if the caller didn't already pass one.
 865      if ($sort === null) {
 866          // If the admin has configured a course sort order, we will use this.
 867          if (!empty($CFG->navsortmycoursessort)) {
 868              $sort = $CFG->navsortmycoursessort . ' ASC';
 869  
 870              // Otherwise we will fall back to the sortorder sorting.
 871          } else {
 872              $sort = 'sortorder ASC';
 873          }
 874      }
 875  
 876      return $visible . $sort;
 877  }
 878  
 879  /**
 880   * Returns course enrolment detailed information.
 881   *
 882   * @param object $course
 883   * @return array of html fragments - can be used to construct lists
 884   */
 885  function enrol_get_course_description_texts($course) {
 886      $lines = array();
 887      $instances = enrol_get_instances($course->id, true);
 888      $plugins = enrol_get_plugins(true);
 889      foreach ($instances as $instance) {
 890          if (!isset($plugins[$instance->enrol])) {
 891              //weird
 892              continue;
 893          }
 894          $plugin = $plugins[$instance->enrol];
 895          $text = $plugin->get_description_text($instance);
 896          if ($text !== NULL) {
 897              $lines[] = $text;
 898          }
 899      }
 900      return $lines;
 901  }
 902  
 903  /**
 904   * Returns list of courses user is enrolled into.
 905   *
 906   * Note: Use {@link enrol_get_all_users_courses()} if you need the list without any capability checks.
 907   *
 908   * The $fields param is a list of field names to ADD so name just the fields you really need,
 909   * which will be added and uniq'd.
 910   *
 911   * @param int $userid User whose courses are returned, defaults to the current user.
 912   * @param bool $onlyactive Return only active enrolments in courses user may see.
 913   * @param string|array $fields Extra fields to be returned (array or comma-separated list).
 914   * @param string|null $sort Comma separated list of fields to sort by, defaults to respecting navsortmycoursessort.
 915   * @return array
 916   */
 917  function enrol_get_users_courses($userid, $onlyactive = false, $fields = null, $sort = null) {
 918      global $DB;
 919  
 920      $courses = enrol_get_all_users_courses($userid, $onlyactive, $fields, $sort);
 921  
 922      // preload contexts and check visibility
 923      if ($onlyactive) {
 924          foreach ($courses as $id=>$course) {
 925              context_helper::preload_from_record($course);
 926              if (!$course->visible) {
 927                  if (!$context = context_course::instance($id)) {
 928                      unset($courses[$id]);
 929                      continue;
 930                  }
 931                  if (!has_capability('moodle/course:viewhiddencourses', $context, $userid)) {
 932                      unset($courses[$id]);
 933                      continue;
 934                  }
 935              }
 936          }
 937      }
 938  
 939      return $courses;
 940  }
 941  
 942  /**
 943   * Returns list of roles per users into course.
 944   *
 945   * @param int $courseid Course id.
 946   * @return array Array[$userid][$roleid] = role_assignment.
 947   */
 948  function enrol_get_course_users_roles(int $courseid) : array {
 949      global $DB;
 950  
 951      $context = context_course::instance($courseid);
 952  
 953      $roles = array();
 954  
 955      $records = $DB->get_recordset('role_assignments', array('contextid' => $context->id));
 956      foreach ($records as $record) {
 957          if (isset($roles[$record->userid]) === false) {
 958              $roles[$record->userid] = array();
 959          }
 960          $roles[$record->userid][$record->roleid] = $record;
 961      }
 962      $records->close();
 963  
 964      return $roles;
 965  }
 966  
 967  /**
 968   * Can user access at least one enrolled course?
 969   *
 970   * Cheat if necessary, but find out as fast as possible!
 971   *
 972   * @param int|stdClass $user null means use current user
 973   * @return bool
 974   */
 975  function enrol_user_sees_own_courses($user = null) {
 976      global $USER;
 977  
 978      if ($user === null) {
 979          $user = $USER;
 980      }
 981      $userid = is_object($user) ? $user->id : $user;
 982  
 983      // Guest account does not have any courses
 984      if (isguestuser($userid) or empty($userid)) {
 985          return false;
 986      }
 987  
 988      // Let's cheat here if this is the current user,
 989      // if user accessed any course recently, then most probably
 990      // we do not need to query the database at all.
 991      if ($USER->id == $userid) {
 992          if (!empty($USER->enrol['enrolled'])) {
 993              foreach ($USER->enrol['enrolled'] as $until) {
 994                  if ($until > time()) {
 995                      return true;
 996                  }
 997              }
 998          }
 999      }
1000  
1001      // Now the slow way.
1002      $courses = enrol_get_all_users_courses($userid, true);
1003      foreach($courses as $course) {
1004          if ($course->visible) {
1005              return true;
1006          }
1007          context_helper::preload_from_record($course);
1008          $context = context_course::instance($course->id);
1009          if (has_capability('moodle/course:viewhiddencourses', $context, $user)) {
1010              return true;
1011          }
1012      }
1013  
1014      return false;
1015  }
1016  
1017  /**
1018   * Returns list of courses user is enrolled into without performing any capability checks.
1019   *
1020   * The $fields param is a list of field names to ADD so name just the fields you really need,
1021   * which will be added and uniq'd.
1022   *
1023   * @param int $userid User whose courses are returned, defaults to the current user.
1024   * @param bool $onlyactive Return only active enrolments in courses user may see.
1025   * @param string|array $fields Extra fields to be returned (array or comma-separated list).
1026   * @param string|null $sort Comma separated list of fields to sort by, defaults to respecting navsortmycoursessort.
1027   * @return array
1028   */
1029  function enrol_get_all_users_courses($userid, $onlyactive = false, $fields = null, $sort = null) {
1030      global $DB;
1031  
1032      // Re-Arrange the course sorting according to the admin settings.
1033      $sort = enrol_get_courses_sortingsql($sort);
1034  
1035      // Guest account does not have any courses
1036      if (isguestuser($userid) or empty($userid)) {
1037          return(array());
1038      }
1039  
1040      $basefields = array('id', 'category', 'sortorder',
1041              'shortname', 'fullname', 'idnumber',
1042              'startdate', 'visible',
1043              'defaultgroupingid',
1044              'groupmode', 'groupmodeforce');
1045  
1046      if (empty($fields)) {
1047          $fields = $basefields;
1048      } else if (is_string($fields)) {
1049          // turn the fields from a string to an array
1050          $fields = explode(',', $fields);
1051          $fields = array_map('trim', $fields);
1052          $fields = array_unique(array_merge($basefields, $fields));
1053      } else if (is_array($fields)) {
1054          $fields = array_unique(array_merge($basefields, $fields));
1055      } else {
1056          throw new coding_exception('Invalid $fields parameter in enrol_get_all_users_courses()');
1057      }
1058      if (in_array('*', $fields)) {
1059          $fields = array('*');
1060      }
1061  
1062      $orderby = "";
1063      $sort    = trim($sort);
1064      if (!empty($sort)) {
1065          $rawsorts = explode(',', $sort);
1066          $sorts = array();
1067          foreach ($rawsorts as $rawsort) {
1068              $rawsort = trim($rawsort);
1069              if (strpos($rawsort, 'c.') === 0) {
1070                  $rawsort = substr($rawsort, 2);
1071              }
1072              $sorts[] = trim($rawsort);
1073          }
1074          $sort = 'c.'.implode(',c.', $sorts);
1075          $orderby = "ORDER BY $sort";
1076      }
1077  
1078      $params = [];
1079  
1080      if ($onlyactive) {
1081          $subwhere = "WHERE ue.status = :active AND e.status = :enabled AND ue.timestart < :now1 AND (ue.timeend = 0 OR ue.timeend > :now2)";
1082          $params['now1']    = round(time(), -2); // improves db caching
1083          $params['now2']    = $params['now1'];
1084          $params['active']  = ENROL_USER_ACTIVE;
1085          $params['enabled'] = ENROL_INSTANCE_ENABLED;
1086      } else {
1087          $subwhere = "";
1088      }
1089  
1090      $coursefields = 'c.' .join(',c.', $fields);
1091      $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
1092      $ccjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = c.id AND ctx.contextlevel = :contextlevel)";
1093      $params['contextlevel'] = CONTEXT_COURSE;
1094  
1095      //note: we can not use DISTINCT + text fields due to Oracle and MS limitations, that is why we have the subselect there
1096      $sql = "SELECT $coursefields $ccselect
1097                FROM {course} c
1098                JOIN (SELECT DISTINCT e.courseid
1099                        FROM {enrol} e
1100                        JOIN {user_enrolments} ue ON (ue.enrolid = e.id AND ue.userid = :userid)
1101                   $subwhere
1102                     ) en ON (en.courseid = c.id)
1103             $ccjoin
1104               WHERE c.id <> " . SITEID . "
1105            $orderby";
1106      $params['userid']  = $userid;
1107  
1108      $courses = $DB->get_records_sql($sql, $params);
1109  
1110      return $courses;
1111  }
1112  
1113  
1114  
1115  /**
1116   * Called when user is about to be deleted.
1117   * @param object $user
1118   * @return void
1119   */
1120  function enrol_user_delete($user) {
1121      global $DB;
1122  
1123      $plugins = enrol_get_plugins(true);
1124      foreach ($plugins as $plugin) {
1125          $plugin->user_delete($user);
1126      }
1127  
1128      // force cleanup of all broken enrolments
1129      $DB->delete_records('user_enrolments', array('userid'=>$user->id));
1130  }
1131  
1132  /**
1133   * Called when course is about to be deleted.
1134   * If a user id is passed, only enrolments that the user has permission to un-enrol will be removed,
1135   * otherwise all enrolments in the course will be removed.
1136   *
1137   * @param stdClass $course
1138   * @param int|null $userid
1139   * @return void
1140   */
1141  function enrol_course_delete($course, $userid = null) {
1142      global $DB;
1143  
1144      $context = context_course::instance($course->id);
1145      $instances = enrol_get_instances($course->id, false);
1146      $plugins = enrol_get_plugins(true);
1147  
1148      if ($userid) {
1149          // If the user id is present, include only course enrolment instances which allow manual unenrolment and
1150          // the given user have a capability to perform unenrolment.
1151          $instances = array_filter($instances, function($instance) use ($userid, $plugins, $context) {
1152              $unenrolcap = "enrol/{$instance->enrol}:unenrol";
1153              return $plugins[$instance->enrol]->allow_unenrol($instance) &&
1154                  has_capability($unenrolcap, $context, $userid);
1155          });
1156      }
1157  
1158      foreach ($instances as $instance) {
1159          if (isset($plugins[$instance->enrol])) {
1160              $plugins[$instance->enrol]->delete_instance($instance);
1161          }
1162          // low level delete in case plugin did not do it
1163          $DB->delete_records('role_assignments', array('itemid'=>$instance->id, 'component'=>'enrol_'.$instance->enrol));
1164          $DB->delete_records('user_enrolments', array('enrolid'=>$instance->id));
1165          $DB->delete_records('enrol', array('id'=>$instance->id));
1166      }
1167  }
1168  
1169  /**
1170   * Try to enrol user via default internal auth plugin.
1171   *
1172   * For now this is always using the manual enrol plugin...
1173   *
1174   * @param $courseid
1175   * @param $userid
1176   * @param $roleid
1177   * @param $timestart
1178   * @param $timeend
1179   * @return bool success
1180   */
1181  function enrol_try_internal_enrol($courseid, $userid, $roleid = null, $timestart = 0, $timeend = 0) {
1182      global $DB;
1183  
1184      //note: this is hardcoded to manual plugin for now
1185  
1186      if (!enrol_is_enabled('manual')) {
1187          return false;
1188      }
1189  
1190      if (!$enrol = enrol_get_plugin('manual')) {
1191          return false;
1192      }
1193      if (!$instances = $DB->get_records('enrol', array('enrol'=>'manual', 'courseid'=>$courseid, 'status'=>ENROL_INSTANCE_ENABLED), 'sortorder,id ASC')) {
1194          return false;
1195      }
1196      $instance = reset($instances);
1197  
1198      $enrol->enrol_user($instance, $userid, $roleid, $timestart, $timeend);
1199  
1200      return true;
1201  }
1202  
1203  /**
1204   * Is there a chance users might self enrol
1205   * @param int $courseid
1206   * @return bool
1207   */
1208  function enrol_selfenrol_available($courseid) {
1209      $result = false;
1210  
1211      $plugins = enrol_get_plugins(true);
1212      $enrolinstances = enrol_get_instances($courseid, true);
1213      foreach($enrolinstances as $instance) {
1214          if (!isset($plugins[$instance->enrol])) {
1215              continue;
1216          }
1217          if ($instance->enrol === 'guest') {
1218              continue;
1219          }
1220          if ($plugins[$instance->enrol]->show_enrolme_link($instance)) {
1221              $result = true;
1222              break;
1223          }
1224      }
1225  
1226      return $result;
1227  }
1228  
1229  /**
1230   * This function returns the end of current active user enrolment.
1231   *
1232   * It deals correctly with multiple overlapping user enrolments.
1233   *
1234   * @param int $courseid
1235   * @param int $userid
1236   * @return int|bool timestamp when active enrolment ends, false means no active enrolment now, 0 means never
1237   */
1238  function enrol_get_enrolment_end($courseid, $userid) {
1239      global $DB;
1240  
1241      $sql = "SELECT ue.*
1242                FROM {user_enrolments} ue
1243                JOIN {enrol} e ON (e.id = ue.enrolid AND e.courseid = :courseid)
1244                JOIN {user} u ON u.id = ue.userid
1245               WHERE ue.userid = :userid AND ue.status = :active AND e.status = :enabled AND u.deleted = 0";
1246      $params = array('enabled'=>ENROL_INSTANCE_ENABLED, 'active'=>ENROL_USER_ACTIVE, 'userid'=>$userid, 'courseid'=>$courseid);
1247  
1248      if (!$enrolments = $DB->get_records_sql($sql, $params)) {
1249          return false;
1250      }
1251  
1252      $changes = array();
1253  
1254      foreach ($enrolments as $ue) {
1255          $start = (int)$ue->timestart;
1256          $end = (int)$ue->timeend;
1257          if ($end != 0 and $end < $start) {
1258              debugging('Invalid enrolment start or end in user_enrolment id:'.$ue->id);
1259              continue;
1260          }
1261          if (isset($changes[$start])) {
1262              $changes[$start] = $changes[$start] + 1;
1263          } else {
1264              $changes[$start] = 1;
1265          }
1266          if ($end === 0) {
1267              // no end
1268          } else if (isset($changes[$end])) {
1269              $changes[$end] = $changes[$end] - 1;
1270          } else {
1271              $changes[$end] = -1;
1272          }
1273      }
1274  
1275      // let's sort then enrolment starts&ends and go through them chronologically,
1276      // looking for current status and the next future end of enrolment
1277      ksort($changes);
1278  
1279      $now = time();
1280      $current = 0;
1281      $present = null;
1282  
1283      foreach ($changes as $time => $change) {
1284          if ($time > $now) {
1285              if ($present === null) {
1286                  // we have just went past current time
1287                  $present = $current;
1288                  if ($present < 1) {
1289                      // no enrolment active
1290                      return false;
1291                  }
1292              }
1293              if ($present !== null) {
1294                  // we are already in the future - look for possible end
1295                  if ($current + $change < 1) {
1296                      return $time;
1297                  }
1298              }
1299          }
1300          $current += $change;
1301      }
1302  
1303      if ($current > 0) {
1304          return 0;
1305      } else {
1306          return false;
1307      }
1308  }
1309  
1310  /**
1311   * Is current user accessing course via this enrolment method?
1312   *
1313   * This is intended for operations that are going to affect enrol instances.
1314   *
1315   * @param stdClass $instance enrol instance
1316   * @return bool
1317   */
1318  function enrol_accessing_via_instance(stdClass $instance) {
1319      global $DB, $USER;
1320  
1321      if (empty($instance->id)) {
1322          return false;
1323      }
1324  
1325      if (is_siteadmin()) {
1326          // Admins may go anywhere.
1327          return false;
1328      }
1329  
1330      return $DB->record_exists('user_enrolments', array('userid'=>$USER->id, 'enrolid'=>$instance->id));
1331  }
1332  
1333  /**
1334   * Returns true if user is enrolled (is participating) in course
1335   * this is intended for students and teachers.
1336   *
1337   * Since 2.2 the result for active enrolments and current user are cached.
1338   *
1339   * @param context $context
1340   * @param int|stdClass $user if null $USER is used, otherwise user object or id expected
1341   * @param string $withcapability extra capability name
1342   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1343   * @return bool
1344   */
1345  function is_enrolled(context $context, $user = null, $withcapability = '', $onlyactive = false) {
1346      global $USER, $DB;
1347  
1348      // First find the course context.
1349      $coursecontext = $context->get_course_context();
1350  
1351      // Make sure there is a real user specified.
1352      if ($user === null) {
1353          $userid = isset($USER->id) ? $USER->id : 0;
1354      } else {
1355          $userid = is_object($user) ? $user->id : $user;
1356      }
1357  
1358      if (empty($userid)) {
1359          // Not-logged-in!
1360          return false;
1361      } else if (isguestuser($userid)) {
1362          // Guest account can not be enrolled anywhere.
1363          return false;
1364      }
1365  
1366      // Note everybody participates on frontpage, so for other contexts...
1367      if ($coursecontext->instanceid != SITEID) {
1368          // Try cached info first - the enrolled flag is set only when active enrolment present.
1369          if ($USER->id == $userid) {
1370              $coursecontext->reload_if_dirty();
1371              if (isset($USER->enrol['enrolled'][$coursecontext->instanceid])) {
1372                  if ($USER->enrol['enrolled'][$coursecontext->instanceid] > time()) {
1373                      if ($withcapability and !has_capability($withcapability, $context, $userid)) {
1374                          return false;
1375                      }
1376                      return true;
1377                  }
1378              }
1379          }
1380  
1381          if ($onlyactive) {
1382              // Look for active enrolments only.
1383              $until = enrol_get_enrolment_end($coursecontext->instanceid, $userid);
1384  
1385              if ($until === false) {
1386                  return false;
1387              }
1388  
1389              if ($USER->id == $userid) {
1390                  if ($until == 0) {
1391                      $until = ENROL_MAX_TIMESTAMP;
1392                  }
1393                  $USER->enrol['enrolled'][$coursecontext->instanceid] = $until;
1394                  if (isset($USER->enrol['tempguest'][$coursecontext->instanceid])) {
1395                      unset($USER->enrol['tempguest'][$coursecontext->instanceid]);
1396                      remove_temp_course_roles($coursecontext);
1397                  }
1398              }
1399  
1400          } else {
1401              // Any enrolment is good for us here, even outdated, disabled or inactive.
1402              $sql = "SELECT 'x'
1403                        FROM {user_enrolments} ue
1404                        JOIN {enrol} e ON (e.id = ue.enrolid AND e.courseid = :courseid)
1405                        JOIN {user} u ON u.id = ue.userid
1406                       WHERE ue.userid = :userid AND u.deleted = 0";
1407              $params = array('userid' => $userid, 'courseid' => $coursecontext->instanceid);
1408              if (!$DB->record_exists_sql($sql, $params)) {
1409                  return false;
1410              }
1411          }
1412      }
1413  
1414      if ($withcapability and !has_capability($withcapability, $context, $userid)) {
1415          return false;
1416      }
1417  
1418      return true;
1419  }
1420  
1421  /**
1422   * Returns an array of joins, wheres and params that will limit the group of
1423   * users to only those enrolled and with given capability (if specified).
1424   *
1425   * Note this join will return duplicate rows for users who have been enrolled
1426   * several times (e.g. as manual enrolment, and as self enrolment). You may
1427   * need to use a SELECT DISTINCT in your query (see get_enrolled_sql for example).
1428   *
1429   * In case is guaranteed some of the joins never match any rows, the resulting
1430   * join_sql->cannotmatchanyrows will be true. This happens when the capability
1431   * is prohibited.
1432   *
1433   * @param context $context
1434   * @param string $prefix optional, a prefix to the user id column
1435   * @param string|array $capability optional, may include a capability name, or array of names.
1436   *      If an array is provided then this is the equivalent of a logical 'OR',
1437   *      i.e. the user needs to have one of these capabilities.
1438   * @param int $group optional, 0 indicates no current group and USERSWITHOUTGROUP users without any group; otherwise the group id
1439   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1440   * @param bool $onlysuspended inverse of onlyactive, consider only suspended enrolments
1441   * @param int $enrolid The enrolment ID. If not 0, only users enrolled using this enrolment method will be returned.
1442   * @return \core\dml\sql_join Contains joins, wheres, params and cannotmatchanyrows
1443   */
1444  function get_enrolled_with_capabilities_join(context $context, $prefix = '', $capability = '', $group = 0,
1445          $onlyactive = false, $onlysuspended = false, $enrolid = 0) {
1446      $uid = $prefix . 'u.id';
1447      $joins = array();
1448      $wheres = array();
1449      $cannotmatchanyrows = false;
1450  
1451      $enrolledjoin = get_enrolled_join($context, $uid, $onlyactive, $onlysuspended, $enrolid);
1452      $joins[] = $enrolledjoin->joins;
1453      $wheres[] = $enrolledjoin->wheres;
1454      $params = $enrolledjoin->params;
1455      $cannotmatchanyrows = $cannotmatchanyrows || $enrolledjoin->cannotmatchanyrows;
1456  
1457      if (!empty($capability)) {
1458          $capjoin = get_with_capability_join($context, $capability, $uid);
1459          $joins[] = $capjoin->joins;
1460          $wheres[] = $capjoin->wheres;
1461          $params = array_merge($params, $capjoin->params);
1462          $cannotmatchanyrows = $cannotmatchanyrows || $capjoin->cannotmatchanyrows;
1463      }
1464  
1465      if ($group) {
1466          $groupjoin = groups_get_members_join($group, $uid, $context);
1467          $joins[] = $groupjoin->joins;
1468          $params = array_merge($params, $groupjoin->params);
1469          if (!empty($groupjoin->wheres)) {
1470              $wheres[] = $groupjoin->wheres;
1471          }
1472          $cannotmatchanyrows = $cannotmatchanyrows || $groupjoin->cannotmatchanyrows;
1473      }
1474  
1475      $joins = implode("\n", $joins);
1476      $wheres[] = "{$prefix}u.deleted = 0";
1477      $wheres = implode(" AND ", $wheres);
1478  
1479      return new \core\dml\sql_join($joins, $wheres, $params, $cannotmatchanyrows);
1480  }
1481  
1482  /**
1483   * Returns array with sql code and parameters returning all ids
1484   * of users enrolled into course.
1485   *
1486   * This function is using 'eu[0-9]+_' prefix for table names and parameters.
1487   *
1488   * @param context $context
1489   * @param string $withcapability
1490   * @param int $groupid 0 means ignore groups, USERSWITHOUTGROUP without any group and any other value limits the result by group id
1491   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1492   * @param bool $onlysuspended inverse of onlyactive, consider only suspended enrolments
1493   * @param int $enrolid The enrolment ID. If not 0, only users enrolled using this enrolment method will be returned.
1494   * @return array list($sql, $params)
1495   */
1496  function get_enrolled_sql(context $context, $withcapability = '', $groupid = 0, $onlyactive = false, $onlysuspended = false,
1497                            $enrolid = 0) {
1498  
1499      // Use unique prefix just in case somebody makes some SQL magic with the result.
1500      static $i = 0;
1501      $i++;
1502      $prefix = 'eu' . $i . '_';
1503  
1504      $capjoin = get_enrolled_with_capabilities_join(
1505              $context, $prefix, $withcapability, $groupid, $onlyactive, $onlysuspended, $enrolid);
1506  
1507      $sql = "SELECT DISTINCT {$prefix}u.id
1508                FROM {user} {$prefix}u
1509              $capjoin->joins
1510               WHERE $capjoin->wheres";
1511  
1512      return array($sql, $capjoin->params);
1513  }
1514  
1515  /**
1516   * Returns array with sql joins and parameters returning all ids
1517   * of users enrolled into course.
1518   *
1519   * This function is using 'ej[0-9]+_' prefix for table names and parameters.
1520   *
1521   * @throws coding_exception
1522   *
1523   * @param context $context
1524   * @param string $useridcolumn User id column used the calling query, e.g. u.id
1525   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1526   * @param bool $onlysuspended inverse of onlyactive, consider only suspended enrolments
1527   * @param int $enrolid The enrolment ID. If not 0, only users enrolled using this enrolment method will be returned.
1528   * @return \core\dml\sql_join Contains joins, wheres, params
1529   */
1530  function get_enrolled_join(context $context, $useridcolumn, $onlyactive = false, $onlysuspended = false, $enrolid = 0) {
1531      // Use unique prefix just in case somebody makes some SQL magic with the result.
1532      static $i = 0;
1533      $i++;
1534      $prefix = 'ej' . $i . '_';
1535  
1536      // First find the course context.
1537      $coursecontext = $context->get_course_context();
1538  
1539      $isfrontpage = ($coursecontext->instanceid == SITEID);
1540  
1541      if ($onlyactive && $onlysuspended) {
1542          throw new coding_exception("Both onlyactive and onlysuspended are set, this is probably not what you want!");
1543      }
1544      if ($isfrontpage && $onlysuspended) {
1545          throw new coding_exception("onlysuspended is not supported on frontpage; please add your own early-exit!");
1546      }
1547  
1548      $joins  = array();
1549      $wheres = array();
1550      $params = array();
1551  
1552      $wheres[] = "1 = 1"; // Prevent broken where clauses later on.
1553  
1554      // Note all users are "enrolled" on the frontpage, but for others...
1555      if (!$isfrontpage) {
1556          $where1 = "{$prefix}ue.status = :{$prefix}active AND {$prefix}e.status = :{$prefix}enabled";
1557          $where2 = "{$prefix}ue.timestart < :{$prefix}now1 AND ({$prefix}ue.timeend = 0 OR {$prefix}ue.timeend > :{$prefix}now2)";
1558  
1559          $enrolconditions = array(
1560              "{$prefix}e.id = {$prefix}ue.enrolid",
1561              "{$prefix}e.courseid = :{$prefix}courseid",
1562          );
1563          if ($enrolid) {
1564              $enrolconditions[] = "{$prefix}e.id = :{$prefix}enrolid";
1565              $params[$prefix . 'enrolid'] = $enrolid;
1566          }
1567          $enrolconditionssql = implode(" AND ", $enrolconditions);
1568          $ejoin = "JOIN {enrol} {$prefix}e ON ($enrolconditionssql)";
1569  
1570          $params[$prefix.'courseid'] = $coursecontext->instanceid;
1571  
1572          if (!$onlysuspended) {
1573              $joins[] = "JOIN {user_enrolments} {$prefix}ue ON {$prefix}ue.userid = $useridcolumn";
1574              $joins[] = $ejoin;
1575              if ($onlyactive) {
1576                  $wheres[] = "$where1 AND $where2";
1577              }
1578          } else {
1579              // Suspended only where there is enrolment but ALL are suspended.
1580              // Consider multiple enrols where one is not suspended or plain role_assign.
1581              $enrolselect = "SELECT DISTINCT {$prefix}ue.userid FROM {user_enrolments} {$prefix}ue $ejoin WHERE $where1 AND $where2";
1582              $joins[] = "JOIN {user_enrolments} {$prefix}ue1 ON {$prefix}ue1.userid = $useridcolumn";
1583              $enrolconditions = array(
1584                  "{$prefix}e1.id = {$prefix}ue1.enrolid",
1585                  "{$prefix}e1.courseid = :{$prefix}_e1_courseid",
1586              );
1587              if ($enrolid) {
1588                  $enrolconditions[] = "{$prefix}e1.id = :{$prefix}e1_enrolid";
1589                  $params[$prefix . 'e1_enrolid'] = $enrolid;
1590              }
1591              $enrolconditionssql = implode(" AND ", $enrolconditions);
1592              $joins[] = "JOIN {enrol} {$prefix}e1 ON ($enrolconditionssql)";
1593              $params["{$prefix}_e1_courseid"] = $coursecontext->instanceid;
1594              $wheres[] = "$useridcolumn NOT IN ($enrolselect)";
1595          }
1596  
1597          if ($onlyactive || $onlysuspended) {
1598              $now = round(time(), -2); // Rounding helps caching in DB.
1599              $params = array_merge($params, array($prefix . 'enabled' => ENROL_INSTANCE_ENABLED,
1600                      $prefix . 'active' => ENROL_USER_ACTIVE,
1601                      $prefix . 'now1' => $now, $prefix . 'now2' => $now));
1602          }
1603      }
1604  
1605      $joins = implode("\n", $joins);
1606      $wheres = implode(" AND ", $wheres);
1607  
1608      return new \core\dml\sql_join($joins, $wheres, $params);
1609  }
1610  
1611  /**
1612   * Returns list of users enrolled into course.
1613   *
1614   * @param context $context
1615   * @param string $withcapability
1616   * @param int $groupid 0 means ignore groups, USERSWITHOUTGROUP without any group and any other value limits the result by group id
1617   * @param string $userfields requested user record fields
1618   * @param string $orderby
1619   * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
1620   * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
1621   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1622   * @return array of user records
1623   */
1624  function get_enrolled_users(context $context, $withcapability = '', $groupid = 0, $userfields = 'u.*', $orderby = null,
1625          $limitfrom = 0, $limitnum = 0, $onlyactive = false) {
1626      global $DB;
1627  
1628      list($esql, $params) = get_enrolled_sql($context, $withcapability, $groupid, $onlyactive);
1629      $sql = "SELECT $userfields
1630                FROM {user} u
1631                JOIN ($esql) je ON je.id = u.id
1632               WHERE u.deleted = 0";
1633  
1634      if ($orderby) {
1635          $sql = "$sql ORDER BY $orderby";
1636      } else {
1637          list($sort, $sortparams) = users_order_by_sql('u');
1638          $sql = "$sql ORDER BY $sort";
1639          $params = array_merge($params, $sortparams);
1640      }
1641  
1642      return $DB->get_records_sql($sql, $params, $limitfrom, $limitnum);
1643  }
1644  
1645  /**
1646   * Counts list of users enrolled into course (as per above function)
1647   *
1648   * @param context $context
1649   * @param string $withcapability
1650   * @param int $groupid 0 means ignore groups, any other value limits the result by group id
1651   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1652   * @return int number of users enrolled into course
1653   */
1654  function count_enrolled_users(context $context, $withcapability = '', $groupid = 0, $onlyactive = false) {
1655      global $DB;
1656  
1657      $capjoin = get_enrolled_with_capabilities_join(
1658              $context, '', $withcapability, $groupid, $onlyactive);
1659  
1660      $sql = "SELECT COUNT(DISTINCT u.id)
1661                FROM {user} u
1662              $capjoin->joins
1663               WHERE $capjoin->wheres AND u.deleted = 0";
1664  
1665      return $DB->count_records_sql($sql, $capjoin->params);
1666  }
1667  
1668  /**
1669   * Send welcome email "from" options.
1670   *
1671   * @return array list of from options
1672   */
1673  function enrol_send_welcome_email_options() {
1674      return [
1675          ENROL_DO_NOT_SEND_EMAIL                 => get_string('no'),
1676          ENROL_SEND_EMAIL_FROM_COURSE_CONTACT    => get_string('sendfromcoursecontact', 'enrol'),
1677          ENROL_SEND_EMAIL_FROM_KEY_HOLDER        => get_string('sendfromkeyholder', 'enrol'),
1678          ENROL_SEND_EMAIL_FROM_NOREPLY           => get_string('sendfromnoreply', 'enrol')
1679      ];
1680  }
1681  
1682  /**
1683   * Serve the user enrolment form as a fragment.
1684   *
1685   * @param array $args List of named arguments for the fragment loader.
1686   * @return string
1687   */
1688  function enrol_output_fragment_user_enrolment_form($args) {
1689      global $CFG, $DB;
1690  
1691      $args = (object) $args;
1692      $context = $args->context;
1693      require_capability('moodle/course:enrolreview', $context);
1694  
1695      $ueid = $args->ueid;
1696      $userenrolment = $DB->get_record('user_enrolments', ['id' => $ueid], '*', MUST_EXIST);
1697      $instance = $DB->get_record('enrol', ['id' => $userenrolment->enrolid], '*', MUST_EXIST);
1698      $plugin = enrol_get_plugin($instance->enrol);
1699      $customdata = [
1700          'ue' => $userenrolment,
1701          'modal' => true,
1702          'enrolinstancename' => $plugin->get_instance_name($instance)
1703      ];
1704  
1705      // Set the data if applicable.
1706      $data = [];
1707      if (isset($args->formdata)) {
1708          $serialiseddata = json_decode($args->formdata);
1709          parse_str($serialiseddata, $data);
1710      }
1711  
1712      require_once("$CFG->dirroot/enrol/editenrolment_form.php");
1713      $mform = new \enrol_user_enrolment_form(null, $customdata, 'post', '', null, true, $data);
1714  
1715      if (!empty($data)) {
1716          $mform->set_data($data);
1717          $mform->is_validated();
1718      }
1719  
1720      return $mform->render();
1721  }
1722  
1723  /**
1724   * Returns the course where a user enrolment belong to.
1725   *
1726   * @param int $ueid user_enrolments id
1727   * @return stdClass
1728   */
1729  function enrol_get_course_by_user_enrolment_id($ueid) {
1730      global $DB;
1731      $sql = "SELECT c.* FROM {user_enrolments} ue
1732                JOIN {enrol} e ON e.id = ue.enrolid
1733                JOIN {course} c ON c.id = e.courseid
1734               WHERE ue.id = :ueid";
1735      return $DB->get_record_sql($sql, array('ueid' => $ueid));
1736  }
1737  
1738  /**
1739   * Return all users enrolled in a course.
1740   *
1741   * @param int $courseid Course id or false if using $uefilter (user enrolment ids may belong to different courses)
1742   * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
1743   * @param array $usersfilter Limit the results obtained to this list of user ids. $uefilter compatibility not guaranteed.
1744   * @param array $uefilter Limit the results obtained to this list of user enrolment ids. $usersfilter compatibility not guaranteed.
1745   * @return stdClass[]
1746   */
1747  function enrol_get_course_users($courseid = false, $onlyactive = false, $usersfilter = array(), $uefilter = array()) {
1748      global $DB;
1749  
1750      if (!$courseid && !$usersfilter && !$uefilter) {
1751          throw new \coding_exception('You should specify at least 1 filter: courseid, users or user enrolments');
1752      }
1753  
1754      $sql = "SELECT ue.id AS ueid, ue.status AS uestatus, ue.enrolid AS ueenrolid, ue.timestart AS uetimestart,
1755               ue.timeend AS uetimeend, ue.modifierid AS uemodifierid, ue.timecreated AS uetimecreated,
1756               ue.timemodified AS uetimemodified, e.status AS estatus,
1757               u.* FROM {user_enrolments} ue
1758                JOIN {enrol} e ON e.id = ue.enrolid
1759                JOIN {user} u ON ue.userid = u.id
1760               WHERE ";
1761      $params = array();
1762  
1763      if ($courseid) {
1764          $conditions[] = "e.courseid = :courseid";
1765          $params['courseid'] = $courseid;
1766      }
1767  
1768      if ($onlyactive) {
1769          $conditions[] = "ue.status = :active AND e.status = :enabled AND ue.timestart < :now1 AND " .
1770              "(ue.timeend = 0 OR ue.timeend > :now2)";
1771          // Improves db caching.
1772          $params['now1']    = round(time(), -2);
1773          $params['now2']    = $params['now1'];
1774          $params['active']  = ENROL_USER_ACTIVE;
1775          $params['enabled'] = ENROL_INSTANCE_ENABLED;
1776      }
1777  
1778      if ($usersfilter) {
1779          list($usersql, $userparams) = $DB->get_in_or_equal($usersfilter, SQL_PARAMS_NAMED);
1780          $conditions[] = "ue.userid $usersql";
1781          $params = $params + $userparams;
1782      }
1783  
1784      if ($uefilter) {
1785          list($uesql, $ueparams) = $DB->get_in_or_equal($uefilter, SQL_PARAMS_NAMED);
1786          $conditions[] = "ue.id $uesql";
1787          $params = $params + $ueparams;
1788      }
1789  
1790      return $DB->get_records_sql($sql . ' ' . implode(' AND ', $conditions), $params);
1791  }
1792  
1793  /**
1794   * Get the list of options for the enrolment period dropdown
1795   *
1796   * @return array List of options for the enrolment period dropdown
1797   */
1798  function enrol_get_period_list() {
1799      $periodmenu = [];
1800      $periodmenu[''] = get_string('unlimited');
1801      for ($i = 1; $i <= 365; $i++) {
1802          $seconds = $i * DAYSECS;
1803          $periodmenu[$seconds] = get_string('numdays', '', $i);
1804      }
1805      return $periodmenu;
1806  }
1807  
1808  /**
1809   * Calculate duration base on start time and end time
1810   *
1811   * @param int $timestart Time start
1812   * @param int $timeend Time end
1813   * @return float|int Calculated duration
1814   */
1815  function enrol_calculate_duration($timestart, $timeend) {
1816      $duration = floor(($timeend - $timestart) / DAYSECS) * DAYSECS;
1817      return $duration;
1818  }
1819  
1820  /**
1821   * Enrolment plugins abstract class.
1822   *
1823   * All enrol plugins should be based on this class,
1824   * this is also the main source of documentation.
1825   *
1826   * @copyright  2010 Petr Skoda {@link http://skodak.org}
1827   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1828   */
1829  abstract class enrol_plugin {
1830      protected $config = null;
1831  
1832      /**
1833       * Returns name of this enrol plugin
1834       * @return string
1835       */
1836      public function get_name() {
1837          // second word in class is always enrol name, sorry, no fancy plugin names with _
1838          $words = explode('_', get_class($this));
1839          return $words[1];
1840      }
1841  
1842      /**
1843       * Returns localised name of enrol instance
1844       *
1845       * @param object $instance (null is accepted too)
1846       * @return string
1847       */
1848      public function get_instance_name($instance) {
1849          if (empty($instance->name)) {
1850              $enrol = $this->get_name();
1851              return get_string('pluginname', 'enrol_'.$enrol);
1852          } else {
1853              $context = context_course::instance($instance->courseid);
1854              return format_string($instance->name, true, array('context'=>$context));
1855          }
1856      }
1857  
1858      /**
1859       * Returns optional enrolment information icons.
1860       *
1861       * This is used in course list for quick overview of enrolment options.
1862       *
1863       * We are not using single instance parameter because sometimes
1864       * we might want to prevent icon repetition when multiple instances
1865       * of one type exist. One instance may also produce several icons.
1866       *
1867       * @param array $instances all enrol instances of this type in one course
1868       * @return array of pix_icon
1869       */
1870      public function get_info_icons(array $instances) {
1871          return array();
1872      }
1873  
1874      /**
1875       * Returns optional enrolment instance description text.
1876       *
1877       * This is used in detailed course information.
1878       *
1879       *
1880       * @param object $instance
1881       * @return string short html text
1882       */
1883      public function get_description_text($instance) {
1884          return null;
1885      }
1886  
1887      /**
1888       * Makes sure config is loaded and cached.
1889       * @return void
1890       */
1891      protected function load_config() {
1892          if (!isset($this->config)) {
1893              $name = $this->get_name();
1894              $this->config = get_config("enrol_$name");
1895          }
1896      }
1897  
1898      /**
1899       * Returns plugin config value
1900       * @param  string $name
1901       * @param  string $default value if config does not exist yet
1902       * @return string value or default
1903       */
1904      public function get_config($name, $default = NULL) {
1905          $this->load_config();
1906          return isset($this->config->$name) ? $this->config->$name : $default;
1907      }
1908  
1909      /**
1910       * Sets plugin config value
1911       * @param  string $name name of config
1912       * @param  string $value string config value, null means delete
1913       * @return string value
1914       */
1915      public function set_config($name, $value) {
1916          $pluginname = $this->get_name();
1917          $this->load_config();
1918          if ($value === NULL) {
1919              unset($this->config->$name);
1920          } else {
1921              $this->config->$name = $value;
1922          }
1923          set_config($name, $value, "enrol_$pluginname");
1924      }
1925  
1926      /**
1927       * Does this plugin assign protected roles are can they be manually removed?
1928       * @return bool - false means anybody may tweak roles, it does not use itemid and component when assigning roles
1929       */
1930      public function roles_protected() {
1931          return true;
1932      }
1933  
1934      /**
1935       * Does this plugin allow manual enrolments?
1936       *
1937       * @param stdClass $instance course enrol instance
1938       * All plugins allowing this must implement 'enrol/xxx:enrol' capability
1939       *
1940       * @return bool - true means user with 'enrol/xxx:enrol' may enrol others freely, false means nobody may add more enrolments manually
1941       */
1942      public function allow_enrol(stdClass $instance) {
1943          return false;
1944      }
1945  
1946      /**
1947       * Does this plugin allow manual unenrolment of all users?
1948       * All plugins allowing this must implement 'enrol/xxx:unenrol' capability
1949       *
1950       * @param stdClass $instance course enrol instance
1951       * @return bool - true means user with 'enrol/xxx:unenrol' may unenrol others freely, false means nobody may touch user_enrolments
1952       */
1953      public function allow_unenrol(stdClass $instance) {
1954          return false;
1955      }
1956  
1957      /**
1958       * Does this plugin allow manual unenrolment of a specific user?
1959       * All plugins allowing this must implement 'enrol/xxx:unenrol' capability
1960       *
1961       * This is useful especially for synchronisation plugins that
1962       * do suspend instead of full unenrolment.
1963       *
1964       * @param stdClass $instance course enrol instance
1965       * @param stdClass $ue record from user_enrolments table, specifies user
1966       *
1967       * @return bool - true means user with 'enrol/xxx:unenrol' may unenrol this user, false means nobody may touch this user enrolment
1968       */
1969      public function allow_unenrol_user(stdClass $instance, stdClass $ue) {
1970          return $this->allow_unenrol($instance);
1971      }
1972  
1973      /**
1974       * Does this plugin allow manual changes in user_enrolments table?
1975       *
1976       * All plugins allowing this must implement 'enrol/xxx:manage' capability
1977       *
1978       * @param stdClass $instance course enrol instance
1979       * @return bool - true means it is possible to change enrol period and status in user_enrolments table
1980       */
1981      public function allow_manage(stdClass $instance) {
1982          return false;
1983      }
1984  
1985      /**
1986       * Does this plugin support some way to user to self enrol?
1987       *
1988       * @param stdClass $instance course enrol instance
1989       *
1990       * @return bool - true means show "Enrol me in this course" link in course UI
1991       */
1992      public function show_enrolme_link(stdClass $instance) {
1993          return false;
1994      }
1995  
1996      /**
1997       * Attempt to automatically enrol current user in course without any interaction,
1998       * calling code has to make sure the plugin and instance are active.
1999       *
2000       * This should return either a timestamp in the future or false.
2001       *
2002       * @param stdClass $instance course enrol instance
2003       * @return bool|int false means not enrolled, integer means timeend
2004       */
2005      public function try_autoenrol(stdClass $instance) {
2006          global $USER;
2007  
2008          return false;
2009      }
2010  
2011      /**
2012       * Attempt to automatically gain temporary guest access to course,
2013       * calling code has to make sure the plugin and instance are active.
2014       *
2015       * This should return either a timestamp in the future or false.
2016       *
2017       * @param stdClass $instance course enrol instance
2018       * @return bool|int false means no guest access, integer means timeend
2019       */
2020      public function try_guestaccess(stdClass $instance) {
2021          global $USER;
2022  
2023          return false;
2024      }
2025  
2026      /**
2027       * Enrol user into course via enrol instance.
2028       *
2029       * @param stdClass $instance
2030       * @param int $userid
2031       * @param int $roleid optional role id
2032       * @param int $timestart 0 means unknown
2033       * @param int $timeend 0 means forever
2034       * @param int $status default to ENROL_USER_ACTIVE for new enrolments, no change by default in updates
2035       * @param bool $recovergrades restore grade history
2036       * @return void
2037       */
2038      public function enrol_user(stdClass $instance, $userid, $roleid = null, $timestart = 0, $timeend = 0, $status = null, $recovergrades = null) {
2039          global $DB, $USER, $CFG; // CFG necessary!!!
2040  
2041          if ($instance->courseid == SITEID) {
2042              throw new coding_exception('invalid attempt to enrol into frontpage course!');
2043          }
2044  
2045          $name = $this->get_name();
2046          $courseid = $instance->courseid;
2047  
2048          if ($instance->enrol !== $name) {
2049              throw new coding_exception('invalid enrol instance!');
2050          }
2051          $context = context_course::instance($instance->courseid, MUST_EXIST);
2052          if (!isset($recovergrades)) {
2053              $recovergrades = $CFG->recovergradesdefault;
2054          }
2055  
2056          $inserted = false;
2057          $updated  = false;
2058          if ($ue = $DB->get_record('user_enrolments', array('enrolid'=>$instance->id, 'userid'=>$userid))) {
2059              //only update if timestart or timeend or status are different.
2060              if ($ue->timestart != $timestart or $ue->timeend != $timeend or (!is_null($status) and $ue->status != $status)) {
2061                  $this->update_user_enrol($instance, $userid, $status, $timestart, $timeend);
2062              }
2063          } else {
2064              $ue = new stdClass();
2065              $ue->enrolid      = $instance->id;
2066              $ue->status       = is_null($status) ? ENROL_USER_ACTIVE : $status;
2067              $ue->userid       = $userid;
2068              $ue->timestart    = $timestart;
2069              $ue->timeend      = $timeend;
2070              $ue->modifierid   = $USER->id;
2071              $ue->timecreated  = time();
2072              $ue->timemodified = $ue->timecreated;
2073              $ue->id = $DB->insert_record('user_enrolments', $ue);
2074  
2075              $inserted = true;
2076          }
2077  
2078          if ($inserted) {
2079              // Trigger event.
2080              $event = \core\event\user_enrolment_created::create(
2081                      array(
2082                          'objectid' => $ue->id,
2083                          'courseid' => $courseid,
2084                          'context' => $context,
2085                          'relateduserid' => $ue->userid,
2086                          'other' => array('enrol' => $name)
2087                          )
2088                      );
2089              $event->trigger();
2090              // Check if course contacts cache needs to be cleared.
2091              core_course_category::user_enrolment_changed($courseid, $ue->userid,
2092                      $ue->status, $ue->timestart, $ue->timeend);
2093          }
2094  
2095          if ($roleid) {
2096              // this must be done after the enrolment event so that the role_assigned event is triggered afterwards
2097              if ($this->roles_protected()) {
2098                  role_assign($roleid, $userid, $context->id, 'enrol_'.$name, $instance->id);
2099              } else {
2100                  role_assign($roleid, $userid, $context->id);
2101              }
2102          }
2103  
2104          // Recover old grades if present.
2105          if ($recovergrades) {
2106              require_once("$CFG->libdir/gradelib.php");
2107              grade_recover_history_grades($userid, $courseid);
2108          }
2109  
2110          // reset current user enrolment caching
2111          if ($userid == $USER->id) {
2112              if (isset($USER->enrol['enrolled'][$courseid])) {
2113                  unset($USER->enrol['enrolled'][$courseid]);
2114              }
2115              if (isset($USER->enrol['tempguest'][$courseid])) {
2116                  unset($USER->enrol['tempguest'][$courseid]);
2117                  remove_temp_course_roles($context);
2118              }
2119          }
2120      }
2121  
2122      /**
2123       * Store user_enrolments changes and trigger event.
2124       *
2125       * @param stdClass $instance
2126       * @param int $userid
2127       * @param int $status
2128       * @param int $timestart
2129       * @param int $timeend
2130       * @return void
2131       */
2132      public function update_user_enrol(stdClass $instance, $userid, $status = NULL, $timestart = NULL, $timeend = NULL) {
2133          global $DB, $USER, $CFG;
2134  
2135          $name = $this->get_name();
2136  
2137          if ($instance->enrol !== $name) {
2138              throw new coding_exception('invalid enrol instance!');
2139          }
2140  
2141          if (!$ue = $DB->get_record('user_enrolments', array('enrolid'=>$instance->id, 'userid'=>$userid))) {
2142              // weird, user not enrolled
2143              return;
2144          }
2145  
2146          $modified = false;
2147          if (isset($status) and $ue->status != $status) {
2148              $ue->status = $status;
2149              $modified = true;
2150          }
2151          if (isset($timestart) and $ue->timestart != $timestart) {
2152              $ue->timestart = $timestart;
2153              $modified = true;
2154          }
2155          if (isset($timeend) and $ue->timeend != $timeend) {
2156              $ue->timeend = $timeend;
2157              $modified = true;
2158          }
2159  
2160          if (!$modified) {
2161              // no change
2162              return;
2163          }
2164  
2165          $ue->modifierid = $USER->id;
2166          $ue->timemodified = time();
2167          $DB->update_record('user_enrolments', $ue);
2168  
2169          // User enrolments have changed, so mark user as dirty.
2170          mark_user_dirty($userid);
2171  
2172          // Invalidate core_access cache for get_suspended_userids.
2173          cache_helper::invalidate_by_definition('core', 'suspended_userids', array(), array($instance->courseid));
2174  
2175          // Trigger event.
2176          $event = \core\event\user_enrolment_updated::create(
2177                  array(
2178                      'objectid' => $ue->id,
2179                      'courseid' => $instance->courseid,
2180                      'context' => context_course::instance($instance->courseid),
2181                      'relateduserid' => $ue->userid,
2182                      'other' => array('enrol' => $name)
2183                      )
2184                  );
2185          $event->trigger();
2186  
2187          core_course_category::user_enrolment_changed($instance->courseid, $ue->userid,
2188                  $ue->status, $ue->timestart, $ue->timeend);
2189      }
2190  
2191      /**
2192       * Unenrol user from course,
2193       * the last unenrolment removes all remaining roles.
2194       *
2195       * @param stdClass $instance
2196       * @param int $userid
2197       * @return void
2198       */
2199      public function unenrol_user(stdClass $instance, $userid) {
2200          global $CFG, $USER, $DB;
2201          require_once("$CFG->dirroot/group/lib.php");
2202  
2203          $name = $this->get_name();
2204          $courseid = $instance->courseid;
2205  
2206          if ($instance->enrol !== $name) {
2207              throw new coding_exception('invalid enrol instance!');
2208          }
2209          $context = context_course::instance($instance->courseid, MUST_EXIST);
2210  
2211          if (!$ue = $DB->get_record('user_enrolments', array('enrolid'=>$instance->id, 'userid'=>$userid))) {
2212              // weird, user not enrolled
2213              return;
2214          }
2215  
2216          // Remove all users groups linked to this enrolment instance.
2217          if ($gms = $DB->get_records('groups_members', array('userid'=>$userid, 'component'=>'enrol_'.$name, 'itemid'=>$instance->id))) {
2218              foreach ($gms as $gm) {
2219                  groups_remove_member($gm->groupid, $gm->userid);
2220              }
2221          }
2222  
2223          role_unassign_all(array('userid'=>$userid, 'contextid'=>$context->id, 'component'=>'enrol_'.$name, 'itemid'=>$instance->id));
2224          $DB->delete_records('user_enrolments', array('id'=>$ue->id));
2225  
2226          // add extra info and trigger event
2227          $ue->courseid  = $courseid;
2228          $ue->enrol     = $name;
2229  
2230          $sql = "SELECT 'x'
2231                    FROM {user_enrolments} ue
2232                    JOIN {enrol} e ON (e.id = ue.enrolid)
2233                   WHERE ue.userid = :userid AND e.courseid = :courseid";
2234          if ($DB->record_exists_sql($sql, array('userid'=>$userid, 'courseid'=>$courseid))) {
2235              $ue->lastenrol = false;
2236  
2237          } else {
2238              // the big cleanup IS necessary!
2239              require_once("$CFG->libdir/gradelib.php");
2240  
2241              // remove all remaining roles
2242              role_unassign_all(array('userid'=>$userid, 'contextid'=>$context->id), true, false);
2243  
2244              //clean up ALL invisible user data from course if this is the last enrolment - groups, grades, etc.
2245              groups_delete_group_members($courseid, $userid);
2246  
2247              grade_user_unenrol($courseid, $userid);
2248  
2249              $DB->delete_records('user_lastaccess', array('userid'=>$userid, 'courseid'=>$courseid));
2250  
2251              $ue->lastenrol = true; // means user not enrolled any more
2252          }
2253          // Trigger event.
2254          $event = \core\event\user_enrolment_deleted::create(
2255                  array(
2256                      'courseid' => $courseid,
2257                      'context' => $context,
2258                      'relateduserid' => $ue->userid,
2259                      'objectid' => $ue->id,
2260                      'other' => array(
2261                          'userenrolment' => (array)$ue,
2262                          'enrol' => $name
2263                          )
2264                      )
2265                  );
2266          $event->trigger();
2267  
2268          // User enrolments have changed, so mark user as dirty.
2269          mark_user_dirty($userid);
2270  
2271          // Check if courrse contacts cache needs to be cleared.
2272          core_course_category::user_enrolment_changed($courseid, $ue->userid, ENROL_USER_SUSPENDED);
2273  
2274          // reset current user enrolment caching
2275          if ($userid == $USER->id) {
2276              if (isset($USER->enrol['enrolled'][$courseid])) {
2277                  unset($USER->enrol['enrolled'][$courseid]);
2278              }
2279              if (isset($USER->enrol['tempguest'][$courseid])) {
2280                  unset($USER->enrol['tempguest'][$courseid]);
2281                  remove_temp_course_roles($context);
2282              }
2283          }
2284      }
2285  
2286      /**
2287       * Forces synchronisation of user enrolments.
2288       *
2289       * This is important especially for external enrol plugins,
2290       * this function is called for all enabled enrol plugins
2291       * right after every user login.
2292       *
2293       * @param object $user user record
2294       * @return void
2295       */
2296      public function sync_user_enrolments($user) {
2297          // override if necessary
2298      }
2299  
2300      /**
2301       * This returns false for backwards compatibility, but it is really recommended.
2302       *
2303       * @since Moodle 3.1
2304       * @return boolean
2305       */
2306      public function use_standard_editing_ui() {
2307          return false;
2308      }
2309  
2310      /**
2311       * Return whether or not, given the current state, it is possible to add a new instance
2312       * of this enrolment plugin to the course.
2313       *
2314       * Default implementation is just for backwards compatibility.
2315       *
2316       * @param int $courseid
2317       * @return boolean
2318       */
2319      public function can_add_instance($courseid) {
2320          $link = $this->get_newinstance_link($courseid);
2321          return !empty($link);
2322      }
2323  
2324      /**
2325       * Return whether or not, given the current state, it is possible to edit an instance
2326       * of this enrolment plugin in the course. Used by the standard editing UI
2327       * to generate a link to the edit instance form if editing is allowed.
2328       *
2329       * @param stdClass $instance
2330       * @return boolean
2331       */
2332      public function can_edit_instance($instance) {
2333          $context = context_course::instance($instance->courseid);
2334  
2335          return has_capability('enrol/' . $instance->enrol . ':config', $context);
2336      }
2337  
2338      /**
2339       * Returns link to page which may be used to add new instance of enrolment plugin in course.
2340       * @param int $courseid
2341       * @return moodle_url page url
2342       */
2343      public function get_newinstance_link($courseid) {
2344          // override for most plugins, check if instance already exists in cases only one instance is supported
2345          return NULL;
2346      }
2347  
2348      /**
2349       * @deprecated since Moodle 2.8 MDL-35864 - please use can_delete_instance() instead.
2350       */
2351      public function instance_deleteable($instance) {
2352          throw new coding_exception('Function enrol_plugin::instance_deleteable() is deprecated, use
2353                  enrol_plugin::can_delete_instance() instead');
2354      }
2355  
2356      /**
2357       * Is it possible to delete enrol instance via standard UI?
2358       *
2359       * @param stdClass  $instance
2360       * @return bool
2361       */
2362      public function can_delete_instance($instance) {
2363          return false;
2364      }
2365  
2366      /**
2367       * Is it possible to hide/show enrol instance via standard UI?
2368       *
2369       * @param stdClass $instance
2370       * @return bool
2371       */
2372      public function can_hide_show_instance($instance) {
2373          debugging("The enrolment plugin '".$this->get_name()."' should override the function can_hide_show_instance().", DEBUG_DEVELOPER);
2374          return true;
2375      }
2376  
2377      /**
2378       * Returns link to manual enrol UI if exists.
2379       * Does the access control tests automatically.
2380       *
2381       * @param object $instance
2382       * @return moodle_url
2383       */
2384      public function get_manual_enrol_link($instance) {
2385          return NULL;
2386      }
2387  
2388      /**
2389       * Returns list of unenrol links for all enrol instances in course.
2390       *
2391       * @param int $instance
2392       * @return moodle_url or NULL if self unenrolment not supported
2393       */
2394      public function get_unenrolself_link($instance) {
2395          global $USER, $CFG, $DB;
2396  
2397          $name = $this->get_name();
2398          if ($instance->enrol !== $name) {
2399              throw new coding_exception('invalid enrol instance!');
2400          }
2401  
2402          if ($instance->courseid == SITEID) {
2403              return NULL;
2404          }
2405  
2406          if (!enrol_is_enabled($name)) {
2407              return NULL;
2408          }
2409  
2410          if ($instance->status != ENROL_INSTANCE_ENABLED) {
2411              return NULL;
2412          }
2413  
2414          if (!file_exists("$CFG->dirroot/enrol/$name/unenrolself.php")) {
2415              return NULL;
2416          }
2417  
2418          $context = context_course::instance($instance->courseid, MUST_EXIST);
2419  
2420          if (!has_capability("enrol/$name:unenrolself", $context)) {
2421              return NULL;
2422          }
2423  
2424          if (!$DB->record_exists('user_enrolments', array('enrolid'=>$instance->id, 'userid'=>$USER->id, 'status'=>ENROL_USER_ACTIVE))) {
2425              return NULL;
2426          }
2427  
2428          return new moodle_url("/enrol/$name/unenrolself.php", array('enrolid'=>$instance->id));
2429      }
2430  
2431      /**
2432       * Adds enrol instance UI to course edit form
2433       *
2434       * @param object $instance enrol instance or null if does not exist yet
2435       * @param MoodleQuickForm $mform
2436       * @param object $data
2437       * @param object $context context of existing course or parent category if course does not exist
2438       * @return void
2439       */
2440      public function course_edit_form($instance, MoodleQuickForm $mform, $data, $context) {
2441          // override - usually at least enable/disable switch, has to add own form header
2442      }
2443  
2444      /**
2445       * Adds form elements to add/edit instance form.
2446       *
2447       * @since Moodle 3.1
2448       * @param object $instance enrol instance or null if does not exist yet
2449       * @param MoodleQuickForm $mform
2450       * @param context $context
2451       * @return void
2452       */
2453      public function edit_instance_form($instance, MoodleQuickForm $mform, $context) {
2454          // Do nothing by default.
2455      }
2456  
2457      /**
2458       * Perform custom validation of the data used to edit the instance.
2459       *
2460       * @since Moodle 3.1
2461       * @param array $data array of ("fieldname"=>value) of submitted data
2462       * @param array $files array of uploaded files "element_name"=>tmp_file_path
2463       * @param object $instance The instance data loaded from the DB.
2464       * @param context $context The context of the instance we are editing
2465       * @return array of "element_name"=>"error_description" if there are errors,
2466       *         or an empty array if everything is OK.
2467       */
2468      public function edit_instance_validation($data, $files, $instance, $context) {
2469          // No errors by default.
2470          debugging('enrol_plugin::edit_instance_validation() is missing. This plugin has no validation!', DEBUG_DEVELOPER);
2471          return array();
2472      }
2473  
2474      /**
2475       * Validates course edit form data
2476       *
2477       * @param object $instance enrol instance or null if does not exist yet
2478       * @param array $data
2479       * @param object $context context of existing course or parent category if course does not exist
2480       * @return array errors array
2481       */
2482      public function course_edit_validation($instance, array $data, $context) {
2483          return array();
2484      }
2485  
2486      /**
2487       * Called after updating/inserting course.
2488       *
2489       * @param bool $inserted true if course just inserted
2490       * @param object $course
2491       * @param object $data form data
2492       * @return void
2493       */
2494      public function course_updated($inserted, $course, $data) {
2495          if ($inserted) {
2496              if ($this->get_config('defaultenrol')) {
2497                  $this->add_default_instance($course);
2498              }
2499          }
2500      }
2501  
2502      /**
2503       * Add new instance of enrol plugin.
2504       * @param object $course
2505       * @param array instance fields
2506       * @return int id of new instance, null if can not be created
2507       */
2508      public function add_instance($course, array $fields = NULL) {
2509          global $DB;
2510  
2511          if ($course->id == SITEID) {
2512              throw new coding_exception('Invalid request to add enrol instance to frontpage.');
2513          }
2514  
2515          $instance = new stdClass();
2516          $instance->enrol          = $this->get_name();
2517          $instance->status         = ENROL_INSTANCE_ENABLED;
2518          $instance->courseid       = $course->id;
2519          $instance->enrolstartdate = 0;
2520          $instance->enrolenddate   = 0;
2521          $instance->timemodified   = time();
2522          $instance->timecreated    = $instance->timemodified;
2523          $instance->sortorder      = $DB->get_field('enrol', 'COALESCE(MAX(sortorder), -1) + 1', array('courseid'=>$course->id));
2524  
2525          $fields = (array)$fields;
2526          unset($fields['enrol']);
2527          unset($fields['courseid']);
2528          unset($fields['sortorder']);
2529          foreach($fields as $field=>$value) {
2530              $instance->$field = $value;
2531          }
2532  
2533          $instance->id = $DB->insert_record('enrol', $instance);
2534  
2535          \core\event\enrol_instance_created::create_from_record($instance)->trigger();
2536  
2537          return $instance->id;
2538      }
2539  
2540      /**
2541       * Update instance of enrol plugin.
2542       *
2543       * @since Moodle 3.1
2544       * @param stdClass $instance
2545       * @param stdClass $data modified instance fields
2546       * @return boolean
2547       */
2548      public function update_instance($instance, $data) {
2549          global $DB;
2550          $properties = array('status', 'name', 'password', 'customint1', 'customint2', 'customint3',
2551                              'customint4', 'customint5', 'customint6', 'customint7', 'customint8',
2552                              'customchar1', 'customchar2', 'customchar3', 'customdec1', 'customdec2',
2553                              'customtext1', 'customtext2', 'customtext3', 'customtext4', 'roleid',
2554                              'enrolperiod', 'expirynotify', 'notifyall', 'expirythreshold',
2555                              'enrolstartdate', 'enrolenddate', 'cost', 'currency');
2556  
2557          foreach ($properties as $key) {
2558              if (isset($data->$key)) {
2559                  $instance->$key = $data->$key;
2560              }
2561          }
2562          $instance->timemodified = time();
2563  
2564          $update = $DB->update_record('enrol', $instance);
2565          if ($update) {
2566              \core\event\enrol_instance_updated::create_from_record($instance)->trigger();
2567          }
2568          return $update;
2569      }
2570  
2571      /**
2572       * Add new instance of enrol plugin with default settings,
2573       * called when adding new instance manually or when adding new course.
2574       *
2575       * Not all plugins support this.
2576       *
2577       * @param object $course
2578       * @return int id of new instance or null if no default supported
2579       */
2580      public function add_default_instance($course) {
2581          return null;
2582      }
2583  
2584      /**
2585       * Update instance status
2586       *
2587       * Override when plugin needs to do some action when enabled or disabled.
2588       *
2589       * @param stdClass $instance
2590       * @param int $newstatus ENROL_INSTANCE_ENABLED, ENROL_INSTANCE_DISABLED
2591       * @return void
2592       */
2593      public function update_status($instance, $newstatus) {
2594          global $DB;
2595  
2596          $instance->status = $newstatus;
2597          $DB->update_record('enrol', $instance);
2598  
2599          $context = context_course::instance($instance->courseid);
2600          \core\event\enrol_instance_updated::create_from_record($instance)->trigger();
2601  
2602          // Invalidate all enrol caches.
2603          $context->mark_dirty();
2604      }
2605  
2606      /**
2607       * Delete course enrol plugin instance, unenrol all users.
2608       * @param object $instance
2609       * @return void
2610       */
2611      public function delete_instance($instance) {
2612          global $DB;
2613  
2614          $name = $this->get_name();
2615          if ($instance->enrol !== $name) {
2616              throw new coding_exception('invalid enrol instance!');
2617          }
2618  
2619          //first unenrol all users
2620          $participants = $DB->get_recordset('user_enrolments', array('enrolid'=>$instance->id));
2621          foreach ($participants as $participant) {
2622              $this->unenrol_user($instance, $participant->userid);
2623          }
2624          $participants->close();
2625  
2626          // now clean up all remainders that were not removed correctly
2627          if ($gms = $DB->get_records('groups_members', array('itemid' => $instance->id, 'component' => 'enrol_' . $name))) {
2628              foreach ($gms as $gm) {
2629                  groups_remove_member($gm->groupid, $gm->userid);
2630              }
2631          }
2632          $DB->delete_records('role_assignments', array('itemid'=>$instance->id, 'component'=>'enrol_'.$name));
2633          $DB->delete_records('user_enrolments', array('enrolid'=>$instance->id));
2634  
2635          // finally drop the enrol row
2636          $DB->delete_records('enrol', array('id'=>$instance->id));
2637  
2638          $context = context_course::instance($instance->courseid);
2639          \core\event\enrol_instance_deleted::create_from_record($instance)->trigger();
2640  
2641          // Invalidate all enrol caches.
2642          $context->mark_dirty();
2643      }
2644  
2645      /**
2646       * Creates course enrol form, checks if form submitted
2647       * and enrols user if necessary. It can also redirect.
2648       *
2649       * @param stdClass $instance
2650       * @return string html text, usually a form in a text box
2651       */
2652      public function enrol_page_hook(stdClass $instance) {
2653          return null;
2654      }
2655  
2656      /**
2657       * Checks if user can self enrol.
2658       *
2659       * @param stdClass $instance enrolment instance
2660       * @param bool $checkuserenrolment if true will check if user enrolment is inactive.
2661       *             used by navigation to improve performance.
2662       * @return bool|string true if successful, else error message or false
2663       */
2664      public function can_self_enrol(stdClass $instance, $checkuserenrolment = true) {
2665          return false;
2666      }
2667  
2668      /**
2669       * Return information for enrolment instance containing list of parameters required
2670       * for enrolment, name of enrolment plugin etc.
2671       *
2672       * @param stdClass $instance enrolment instance
2673       * @return array instance info.
2674       */
2675      public function get_enrol_info(stdClass $instance) {
2676          return null;
2677      }
2678  
2679      /**
2680       * Adds navigation links into course admin block.
2681       *
2682       * By defaults looks for manage links only.
2683       *
2684       * @param navigation_node $instancesnode
2685       * @param stdClass $instance
2686       * @return void
2687       */
2688      public function add_course_navigation($instancesnode, stdClass $instance) {
2689          if ($this->use_standard_editing_ui()) {
2690              $context = context_course::instance($instance->courseid);
2691              $cap = 'enrol/' . $instance->enrol . ':config';
2692              if (has_capability($cap, $context)) {
2693                  $linkparams = array('courseid' => $instance->courseid, 'id' => $instance->id, 'type' => $instance->enrol);
2694                  $managelink = new moodle_url('/enrol/editinstance.php', $linkparams);
2695                  $instancesnode->add($this->get_instance_name($instance), $managelink, navigation_node::TYPE_SETTING);
2696              }
2697          }
2698      }
2699  
2700      /**
2701       * Returns edit icons for the page with list of instances
2702       * @param stdClass $instance
2703       * @return array
2704       */
2705      public function get_action_icons(stdClass $instance) {
2706          global $OUTPUT;
2707  
2708          $icons = array();
2709          if ($this->use_standard_editing_ui()) {
2710              $linkparams = array('courseid' => $instance->courseid, 'id' => $instance->id, 'type' => $instance->enrol);
2711              $editlink = new moodle_url("/enrol/editinstance.php", $linkparams);
2712              $icons[] = $OUTPUT->action_icon($editlink, new pix_icon('t/edit', get_string('edit'), 'core',
2713                  array('class' => 'iconsmall')));
2714          }
2715          return $icons;
2716      }
2717  
2718      /**
2719       * Reads version.php and determines if it is necessary
2720       * to execute the cron job now.
2721       * @return bool
2722       */
2723      public function is_cron_required() {
2724          global $CFG;
2725  
2726          $name = $this->get_name();
2727          $versionfile = "$CFG->dirroot/enrol/$name/version.php";
2728          $plugin = new stdClass();
2729          include($versionfile);
2730          if (empty($plugin->cron)) {
2731              return false;
2732          }
2733          $lastexecuted = $this->get_config('lastcron', 0);
2734          if ($lastexecuted + $plugin->cron < time()) {
2735              return true;
2736          } else {
2737              return false;
2738          }
2739      }
2740  
2741      /**
2742       * Called for all enabled enrol plugins that returned true from is_cron_required().
2743       * @return void
2744       */
2745      public function cron() {
2746      }
2747  
2748      /**
2749       * Called when user is about to be deleted
2750       * @param object $user
2751       * @return void
2752       */
2753      public function user_delete($user) {
2754          global $DB;
2755  
2756          $sql = "SELECT e.*
2757                    FROM {enrol} e
2758                    JOIN {user_enrolments} ue ON (ue.enrolid = e.id)
2759                   WHERE e.enrol = :name AND ue.userid = :userid";
2760          $params = array('name'=>$this->get_name(), 'userid'=>$user->id);
2761  
2762          $rs = $DB->get_recordset_sql($sql, $params);
2763          foreach($rs as $instance) {
2764              $this->unenrol_user($instance, $user->id);
2765          }
2766          $rs->close();
2767      }
2768  
2769      /**
2770       * Returns an enrol_user_button that takes the user to a page where they are able to
2771       * enrol users into the managers course through this plugin.
2772       *
2773       * Optional: If the plugin supports manual enrolments it can choose to override this
2774       * otherwise it shouldn't
2775       *
2776       * @param course_enrolment_manager $manager
2777       * @return enrol_user_button|false
2778       */
2779      public function get_manual_enrol_button(course_enrolment_manager $manager) {
2780          return false;
2781      }
2782  
2783      /**
2784       * Gets an array of the user enrolment actions
2785       *
2786       * @param course_enrolment_manager $manager
2787       * @param stdClass $ue
2788       * @return array An array of user_enrolment_actions
2789       */
2790      public function get_user_enrolment_actions(course_enrolment_manager $manager, $ue) {
2791          $actions = [];
2792          $context = $manager->get_context();
2793          $instance = $ue->enrolmentinstance;
2794          $params = $manager->get_moodlepage()->url->params();
2795          $params['ue'] = $ue->id;
2796  
2797          // Edit enrolment action.
2798          if ($this->allow_manage($instance) && has_capability("enrol/{$instance->enrol}:manage", $context)) {
2799              $title = get_string('editenrolment', 'enrol');
2800              $icon = new pix_icon('t/edit', $title);
2801              $url = new moodle_url('/enrol/editenrolment.php', $params);
2802              $actionparams = [
2803                  'class' => 'editenrollink',
2804                  'rel' => $ue->id,
2805                  'data-action' => ENROL_ACTION_EDIT
2806              ];
2807              $actions[] = new user_enrolment_action($icon, $title, $url, $actionparams);
2808          }
2809  
2810          // Unenrol action.
2811          if ($this->allow_unenrol_user($instance, $ue) && has_capability("enrol/{$instance->enrol}:unenrol", $context)) {
2812              $title = get_string('unenrol', 'enrol');
2813              $icon = new pix_icon('t/delete', $title);
2814              $url = new moodle_url('/enrol/unenroluser.php', $params);
2815              $actionparams = [
2816                  'class' => 'unenrollink',
2817                  'rel' => $ue->id,
2818                  'data-action' => ENROL_ACTION_UNENROL
2819              ];
2820              $actions[] = new user_enrolment_action($icon, $title, $url, $actionparams);
2821          }
2822          return $actions;
2823      }
2824  
2825      /**
2826       * Returns true if the plugin has one or more bulk operations that can be performed on
2827       * user enrolments.
2828       *
2829       * @param course_enrolment_manager $manager
2830       * @return bool
2831       */
2832      public function has_bulk_operations(course_enrolment_manager $manager) {
2833         return false;
2834      }
2835  
2836      /**
2837       * Return an array of enrol_bulk_enrolment_operation objects that define
2838       * the bulk actions that can be performed on user enrolments by the plugin.
2839       *
2840       * @param course_enrolment_manager $manager
2841       * @return array
2842       */
2843      public function get_bulk_operations(course_enrolment_manager $manager) {
2844          return array();
2845      }
2846  
2847      /**
2848       * Do any enrolments need expiration processing.
2849       *
2850       * Plugins that want to call this functionality must implement 'expiredaction' config setting.
2851       *
2852       * @param progress_trace $trace
2853       * @param int $courseid one course, empty mean all
2854       * @return bool true if any data processed, false if not
2855       */
2856      public function process_expirations(progress_trace $trace, $courseid = null) {
2857          global $DB;
2858  
2859          $name = $this->get_name();
2860          if (!enrol_is_enabled($name)) {
2861              $trace->finished();
2862              return false;
2863          }
2864  
2865          $processed = false;
2866          $params = array();
2867          $coursesql = "";
2868          if ($courseid) {
2869              $coursesql = "AND e.courseid = :courseid";
2870          }
2871  
2872          // Deal with expired accounts.
2873          $action = $this->get_config('expiredaction', ENROL_EXT_REMOVED_KEEP);
2874  
2875          if ($action == ENROL_EXT_REMOVED_UNENROL) {
2876              $instances = array();
2877              $sql = "SELECT ue.*, e.courseid, c.id AS contextid
2878                        FROM {user_enrolments} ue
2879                        JOIN {enrol} e ON (e.id = ue.enrolid AND e.enrol = :enrol)
2880                        JOIN {context} c ON (c.instanceid = e.courseid AND c.contextlevel = :courselevel)
2881                       WHERE ue.timeend > 0 AND ue.timeend < :now $coursesql";
2882              $params = array('now'=>time(), 'courselevel'=>CONTEXT_COURSE, 'enrol'=>$name, 'courseid'=>$courseid);
2883  
2884              $rs = $DB->get_recordset_sql($sql, $params);
2885              foreach ($rs as $ue) {
2886                  if (!$processed) {
2887                      $trace->output("Starting processing of enrol_$name expirations...");
2888                      $processed = true;
2889                  }
2890                  if (empty($instances[$ue->enrolid])) {
2891                      $instances[$ue->enrolid] = $DB->get_record('enrol', array('id'=>$ue->enrolid));
2892                  }
2893                  $instance = $instances[$ue->enrolid];
2894                  if (!$this->roles_protected()) {
2895                      // Let's just guess what extra roles are supposed to be removed.
2896                      if ($instance->roleid) {
2897                          role_unassign($instance->roleid, $ue->userid, $ue->contextid);
2898                      }
2899                  }
2900                  // The unenrol cleans up all subcontexts if this is the only course enrolment for this user.
2901                  $this->unenrol_user($instance, $ue->userid);
2902                  $trace->output("Unenrolling expired user $ue->userid from course $instance->courseid", 1);
2903              }
2904              $rs->close();
2905              unset($instances);
2906  
2907          } else if ($action == ENROL_EXT_REMOVED_SUSPENDNOROLES or $action == ENROL_EXT_REMOVED_SUSPEND) {
2908              $instances = array();
2909              $sql = "SELECT ue.*, e.courseid, c.id AS contextid
2910                        FROM {user_enrolments} ue
2911                        JOIN {enrol} e ON (e.id = ue.enrolid AND e.enrol = :enrol)
2912                        JOIN {context} c ON (c.instanceid = e.courseid AND c.contextlevel = :courselevel)
2913                       WHERE ue.timeend > 0 AND ue.timeend < :now
2914                             AND ue.status = :useractive $coursesql";
2915              $params = array('now'=>time(), 'courselevel'=>CONTEXT_COURSE, 'useractive'=>ENROL_USER_ACTIVE, 'enrol'=>$name, 'courseid'=>$courseid);
2916              $rs = $DB->get_recordset_sql($sql, $params);
2917              foreach ($rs as $ue) {
2918                  if (!$processed) {
2919                      $trace->output("Starting processing of enrol_$name expirations...");
2920                      $processed = true;
2921                  }
2922                  if (empty($instances[$ue->enrolid])) {
2923                      $instances[$ue->enrolid] = $DB->get_record('enrol', array('id'=>$ue->enrolid));
2924                  }
2925                  $instance = $instances[$ue->enrolid];
2926  
2927                  if ($action == ENROL_EXT_REMOVED_SUSPENDNOROLES) {
2928                      if (!$this->roles_protected()) {
2929                          // Let's just guess what roles should be removed.
2930                          $count = $DB->count_records('role_assignments', array('userid'=>$ue->userid, 'contextid'=>$ue->contextid));
2931                          if ($count == 1) {
2932                              role_unassign_all(array('userid'=>$ue->userid, 'contextid'=>$ue->contextid, 'component'=>'', 'itemid'=>0));
2933  
2934                          } else if ($count > 1 and $instance->roleid) {
2935                              role_unassign($instance->roleid, $ue->userid, $ue->contextid, '', 0);
2936                          }
2937                      }
2938                      // In any case remove all roles that belong to this instance and user.
2939                      role_unassign_all(array('userid'=>$ue->userid, 'contextid'=>$ue->contextid, 'component'=>'enrol_'.$name, 'itemid'=>$instance->id), true);
2940                      // Final cleanup of subcontexts if there are no more course roles.
2941                      if (0 == $DB->count_records('role_assignments', array('userid'=>$ue->userid, 'contextid'=>$ue->contextid))) {
2942                          role_unassign_all(array('userid'=>$ue->userid, 'contextid'=>$ue->contextid, 'component'=>'', 'itemid'=>0), true);
2943                      }
2944                  }
2945  
2946                  $this->update_user_enrol($instance, $ue->userid, ENROL_USER_SUSPENDED);
2947                  $trace->output("Suspending expired user $ue->userid in course $instance->courseid", 1);
2948              }
2949              $rs->close();
2950              unset($instances);
2951  
2952          } else {
2953              // ENROL_EXT_REMOVED_KEEP means no changes.
2954          }
2955  
2956          if ($processed) {
2957              $trace->output("...finished processing of enrol_$name expirations");
2958          } else {
2959              $trace->output("No expired enrol_$name enrolments detected");
2960          }
2961          $trace->finished();
2962  
2963          return $processed;
2964      }
2965  
2966      /**
2967       * Send expiry notifications.
2968       *
2969       * Plugin that wants to have expiry notification MUST implement following:
2970       * - expirynotifyhour plugin setting,
2971       * - configuration options in instance edit form (expirynotify, notifyall and expirythreshold),
2972       * - notification strings (expirymessageenrollersubject, expirymessageenrollerbody,
2973       *   expirymessageenrolledsubject and expirymessageenrolledbody),
2974       * - expiry_notification provider in db/messages.php,
2975       * - upgrade code that sets default thresholds for existing courses (should be 1 day),
2976       * - something that calls this method, such as cron.
2977       *
2978       * @param progress_trace $trace (accepts bool for backwards compatibility only)
2979       */
2980      public function send_expiry_notifications($trace) {
2981          global $DB, $CFG;
2982  
2983          $name = $this->get_name();
2984          if (!enrol_is_enabled($name)) {
2985              $trace->finished();
2986              return;
2987          }
2988  
2989          // Unfortunately this may take a long time, it should not be interrupted,
2990          // otherwise users get duplicate notification.
2991  
2992          core_php_time_limit::raise();
2993          raise_memory_limit(MEMORY_HUGE);
2994  
2995  
2996          $expirynotifylast = $this->get_config('expirynotifylast', 0);
2997          $expirynotifyhour = $this->get_config('expirynotifyhour');
2998          if (is_null($expirynotifyhour)) {
2999              debugging("send_expiry_notifications() in $name enrolment plugin needs expirynotifyhour setting");
3000              $trace->finished();
3001              return;
3002          }
3003  
3004          if (!($trace instanceof progress_trace)) {
3005              $trace = $trace ? new text_progress_trace() : new null_progress_trace();
3006              debugging('enrol_plugin::send_expiry_notifications() now expects progress_trace instance as parameter!', DEBUG_DEVELOPER);
3007          }
3008  
3009          $timenow = time();
3010          $notifytime = usergetmidnight($timenow, $CFG->timezone) + ($expirynotifyhour * 3600);
3011  
3012          if ($expirynotifylast > $notifytime) {
3013              $trace->output($name.' enrolment expiry notifications were already sent today at '.userdate($expirynotifylast, '', $CFG->timezone).'.');
3014              $trace->finished();
3015              return;
3016  
3017          } else if ($timenow < $notifytime) {
3018              $trace->output($name.' enrolment expiry notifications will be sent at '.userdate($notifytime, '', $CFG->timezone).'.');
3019              $trace->finished();
3020              return;
3021          }
3022  
3023          $trace->output('Processing '.$name.' enrolment expiration notifications...');
3024  
3025          // Notify users responsible for enrolment once every day.
3026          $sql = "SELECT ue.*, e.expirynotify, e.notifyall, e.expirythreshold, e.courseid, c.fullname
3027                    FROM {user_enrolments} ue
3028                    JOIN {enrol} e ON (e.id = ue.enrolid AND e.enrol = :name AND e.expirynotify > 0 AND e.status = :enabled)
3029                    JOIN {course} c ON (c.id = e.courseid)
3030                    JOIN {user} u ON (u.id = ue.userid AND u.deleted = 0 AND u.suspended = 0)
3031                   WHERE ue.status = :active AND ue.timeend > 0 AND ue.timeend > :now1 AND ue.timeend < (e.expirythreshold + :now2)
3032                ORDER BY ue.enrolid ASC, u.lastname ASC, u.firstname ASC, u.id ASC";
3033          $params = array('enabled'=>ENROL_INSTANCE_ENABLED, 'active'=>ENROL_USER_ACTIVE, 'now1'=>$timenow, 'now2'=>$timenow, 'name'=>$name);
3034  
3035          $rs = $DB->get_recordset_sql($sql, $params);
3036  
3037          $lastenrollid = 0;
3038          $users = array();
3039  
3040          foreach($rs as $ue) {
3041              if ($lastenrollid and $lastenrollid != $ue->enrolid) {
3042                  $this->notify_expiry_enroller($lastenrollid, $users, $trace);
3043                  $users = array();
3044              }
3045              $lastenrollid = $ue->enrolid;
3046  
3047              $enroller = $this->get_enroller($ue->enrolid);
3048              $context = context_course::instance($ue->courseid);
3049  
3050              $user = $DB->get_record('user', array('id'=>$ue->userid));
3051  
3052              $users[] = array('fullname'=>fullname($user, has_capability('moodle/site:viewfullnames', $context, $enroller)), 'timeend'=>$ue->timeend);
3053  
3054              if (!$ue->notifyall) {
3055                  continue;
3056              }
3057  
3058              if ($ue->timeend - $ue->expirythreshold + 86400 < $timenow) {
3059                  // Notify enrolled users only once at the start of the threshold.
3060                  $trace->output("user $ue->userid was already notified that enrolment in course $ue->courseid expires on ".userdate($ue->timeend, '', $CFG->timezone), 1);
3061                  continue;
3062              }
3063  
3064              $this->notify_expiry_enrolled($user, $ue, $trace);
3065          }
3066          $rs->close();
3067  
3068          if ($lastenrollid and $users) {
3069              $this->notify_expiry_enroller($lastenrollid, $users, $trace);
3070          }
3071  
3072          $trace->output('...notification processing finished.');
3073          $trace->finished();
3074  
3075          $this->set_config('expirynotifylast', $timenow);
3076      }
3077  
3078      /**
3079       * Returns the user who is responsible for enrolments for given instance.
3080       *
3081       * Override if plugin knows anybody better than admin.
3082       *
3083       * @param int $instanceid enrolment instance id
3084       * @return stdClass user record
3085       */
3086      protected function get_enroller($instanceid) {
3087          return get_admin();
3088      }
3089  
3090      /**
3091       * Notify user about incoming expiration of their enrolment,
3092       * it is called only if notification of enrolled users (aka students) is enabled in course.
3093       *
3094       * This is executed only once for each expiring enrolment right
3095       * at the start of the expiration threshold.
3096       *
3097       * @param stdClass $user
3098       * @param stdClass $ue
3099       * @param progress_trace $trace
3100       */
3101      protected function notify_expiry_enrolled($user, $ue, progress_trace $trace) {
3102          global $CFG;
3103  
3104          $name = $this->get_name();
3105  
3106          $oldforcelang = force_current_language($user->lang);
3107  
3108          $enroller = $this->get_enroller($ue->enrolid);
3109          $context = context_course::instance($ue->courseid);
3110  
3111          $a = new stdClass();
3112          $a->course   = format_string($ue->fullname, true, array('context'=>$context));
3113          $a->user     = fullname($user, true);
3114          $a->timeend  = userdate($ue->timeend, '', $user->timezone);
3115          $a->enroller = fullname($enroller, has_capability('moodle/site:viewfullnames', $context, $user));
3116  
3117          $subject = get_string('expirymessageenrolledsubject', 'enrol_'.$name, $a);
3118          $body = get_string('expirymessageenrolledbody', 'enrol_'.$name, $a);
3119  
3120          $message = new \core\message\message();
3121          $message->courseid          = $ue->courseid;
3122          $message->notification      = 1;
3123          $message->component         = 'enrol_'.$name;
3124          $message->name              = 'expiry_notification';
3125          $message->userfrom          = $enroller;
3126          $message->userto            = $user;
3127          $message->subject           = $subject;
3128          $message->fullmessage       = $body;
3129          $message->fullmessageformat = FORMAT_MARKDOWN;
3130          $message->fullmessagehtml   = markdown_to_html($body);
3131          $message->smallmessage      = $subject;
3132          $message->contexturlname    = $a->course;
3133          $message->contexturl        = (string)new moodle_url('/course/view.php', array('id'=>$ue->courseid));
3134  
3135          if (message_send($message)) {
3136              $trace->output("notifying user $ue->userid that enrolment in course $ue->courseid expires on ".userdate($ue->timeend, '', $CFG->timezone), 1);
3137          } else {
3138              $trace->output("error notifying user $ue->userid that enrolment in course $ue->courseid expires on ".userdate($ue->timeend, '', $CFG->timezone), 1);
3139          }
3140  
3141          force_current_language($oldforcelang);
3142      }
3143  
3144      /**
3145       * Notify person responsible for enrolments that some user enrolments will be expired soon,
3146       * it is called only if notification of enrollers (aka teachers) is enabled in course.
3147       *
3148       * This is called repeatedly every day for each course if there are any pending expiration
3149       * in the expiration threshold.
3150       *
3151       * @param int $eid
3152       * @param array $users
3153       * @param progress_trace $trace
3154       */
3155      protected function notify_expiry_enroller($eid, $users, progress_trace $trace) {
3156          global $DB;
3157  
3158          $name = $this->get_name();
3159  
3160          $instance = $DB->get_record('enrol', array('id'=>$eid, 'enrol'=>$name));
3161          $context = context_course::instance($instance->courseid);
3162          $course = $DB->get_record('course', array('id'=>$instance->courseid));
3163  
3164          $enroller = $this->get_enroller($instance->id);
3165          $admin = get_admin();
3166  
3167          $oldforcelang = force_current_language($enroller->lang);
3168  
3169          foreach($users as $key=>$info) {
3170              $users[$key] = '* '.$info['fullname'].' - '.userdate($info['timeend'], '', $enroller->timezone);
3171          }
3172  
3173          $a = new stdClass();
3174          $a->course    = format_string($course->fullname, true, array('context'=>$context));
3175          $a->threshold = get_string('numdays', '', $instance->expirythreshold / (60*60*24));
3176          $a->users     = implode("\n", $users);
3177          $a->extendurl = (string)new moodle_url('/user/index.php', array('id'=>$instance->courseid));
3178  
3179          $subject = get_string('expirymessageenrollersubject', 'enrol_'.$name, $a);
3180          $body = get_string('expirymessageenrollerbody', 'enrol_'.$name, $a);
3181  
3182          $message = new \core\message\message();
3183          $message->courseid          = $course->id;
3184          $message->notification      = 1;
3185          $message->component         = 'enrol_'.$name;
3186          $message->name              = 'expiry_notification';
3187          $message->userfrom          = $admin;
3188          $message->userto            = $enroller;
3189          $message->subject           = $subject;
3190          $message->fullmessage       = $body;
3191          $message->fullmessageformat = FORMAT_MARKDOWN;
3192          $message->fullmessagehtml   = markdown_to_html($body);
3193          $message->smallmessage      = $subject;
3194          $message->contexturlname    = $a->course;
3195          $message->contexturl        = $a->extendurl;
3196  
3197          if (message_send($message)) {
3198              $trace->output("notifying user $enroller->id about all expiring $name enrolments in course $instance->courseid", 1);
3199          } else {
3200              $trace->output("error notifying user $enroller->id about all expiring $name enrolments in course $instance->courseid", 1);
3201          }
3202  
3203          force_current_language($oldforcelang);
3204      }
3205  
3206      /**
3207       * Backup execution step hook to annotate custom fields.
3208       *
3209       * @param backup_enrolments_execution_step $step
3210       * @param stdClass $enrol
3211       */
3212      public function backup_annotate_custom_fields(backup_enrolments_execution_step $step, stdClass $enrol) {
3213          // Override as necessary to annotate custom fields in the enrol table.
3214      }
3215  
3216      /**
3217       * Automatic enrol sync executed during restore.
3218       * Useful for automatic sync by course->idnumber or course category.
3219       * @param stdClass $course course record
3220       */
3221      public function restore_sync_course($course) {
3222          // Override if necessary.
3223      }
3224  
3225      /**
3226       * Restore instance and map settings.
3227       *
3228       * @param restore_enrolments_structure_step $step
3229       * @param stdClass $data
3230       * @param stdClass $course
3231       * @param int $oldid
3232       */
3233      public function restore_instance(restore_enrolments_structure_step $step, stdClass $data, $course, $oldid) {
3234          // Do not call this from overridden methods, restore and set new id there.
3235          $step->set_mapping('enrol', $oldid, 0);
3236      }
3237  
3238      /**
3239       * Restore user enrolment.
3240       *
3241       * @param restore_enrolments_structure_step $step
3242       * @param stdClass $data
3243       * @param stdClass $instance
3244       * @param int $oldinstancestatus
3245       * @param int $userid
3246       */
3247      public function restore_user_enrolment(restore_enrolments_structure_step $step, $data, $instance, $userid, $oldinstancestatus) {
3248          // Override as necessary if plugin supports restore of enrolments.
3249      }
3250  
3251      /**
3252       * Restore role assignment.
3253       *
3254       * @param stdClass $instance
3255       * @param int $roleid
3256       * @param int $userid
3257       * @param int $contextid
3258       */
3259      public function restore_role_assignment($instance, $roleid, $userid, $contextid) {
3260          // No role assignment by default, override if necessary.
3261      }
3262  
3263      /**
3264       * Restore user group membership.
3265       * @param stdClass $instance
3266       * @param int $groupid
3267       * @param int $userid
3268       */
3269      public function restore_group_member($instance, $groupid, $userid) {
3270          // Implement if you want to restore protected group memberships,
3271          // usually this is not necessary because plugins should be able to recreate the memberships automatically.
3272      }
3273  
3274      /**
3275       * Returns defaults for new instances.
3276       * @since Moodle 3.1
3277       * @return array
3278       */
3279      public function get_instance_defaults() {
3280          return array();
3281      }
3282  
3283      /**
3284       * Validate a list of parameter names and types.
3285       * @since Moodle 3.1
3286       *
3287       * @param array $data array of ("fieldname"=>value) of submitted data
3288       * @param array $rules array of ("fieldname"=>PARAM_X types - or "fieldname"=>array( list of valid options )
3289       * @return array of "element_name"=>"error_description" if there are errors,
3290       *         or an empty array if everything is OK.
3291       */
3292      public function validate_param_types($data, $rules) {
3293          $errors = array();
3294          $invalidstr = get_string('invaliddata', 'error');
3295          foreach ($rules as $fieldname => $rule) {
3296              if (is_array($rule)) {
3297                  if (!in_array($data[$fieldname], $rule)) {
3298                      $errors[$fieldname] = $invalidstr;
3299                  }
3300              } else {
3301                  if ($data[$fieldname] != clean_param($data[$fieldname], $rule)) {
3302                      $errors[$fieldname] = $invalidstr;
3303                  }
3304              }
3305          }
3306          return $errors;
3307      }
3308  }