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  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
/cohort/ -> lib.php (source)

Differences Between: [Versions 310 and 402] [Versions 311 and 402] [Versions 39 and 402] [Versions 400 and 402] [Versions 401 and 402]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Cohort related management functions, this file needs to be included manually.
  19   *
  20   * @package    core_cohort
  21   * @copyright  2010 Petr Skoda  {@link http://skodak.org}
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  defined('MOODLE_INTERNAL') || die();
  26  
  27  define('COHORT_ALL', 0);
  28  define('COHORT_COUNT_MEMBERS', 1);
  29  define('COHORT_COUNT_ENROLLED_MEMBERS', 3);
  30  define('COHORT_WITH_MEMBERS_ONLY', 5);
  31  define('COHORT_WITH_ENROLLED_MEMBERS_ONLY', 17);
  32  define('COHORT_WITH_NOTENROLLED_MEMBERS_ONLY', 23);
  33  
  34  /**
  35   * Add new cohort.
  36   *
  37   * @param  stdClass $cohort
  38   * @return int new cohort id
  39   */
  40  function cohort_add_cohort($cohort) {
  41      global $DB, $CFG;
  42  
  43      if (!isset($cohort->name)) {
  44          throw new coding_exception('Missing cohort name in cohort_add_cohort().');
  45      }
  46      if (!isset($cohort->idnumber)) {
  47          $cohort->idnumber = NULL;
  48      }
  49      if (!isset($cohort->description)) {
  50          $cohort->description = '';
  51      }
  52      if (!isset($cohort->descriptionformat)) {
  53          $cohort->descriptionformat = FORMAT_HTML;
  54      }
  55      if (!isset($cohort->visible)) {
  56          $cohort->visible = 1;
  57      }
  58      if (empty($cohort->component)) {
  59          $cohort->component = '';
  60      }
  61      if (empty($CFG->allowcohortthemes) && isset($cohort->theme)) {
  62          unset($cohort->theme);
  63      }
  64      if (empty($cohort->theme) || empty($CFG->allowcohortthemes)) {
  65          $cohort->theme = '';
  66      }
  67      if (!isset($cohort->timecreated)) {
  68          $cohort->timecreated = time();
  69      }
  70      if (!isset($cohort->timemodified)) {
  71          $cohort->timemodified = $cohort->timecreated;
  72      }
  73  
  74      $cohort->id = $DB->insert_record('cohort', $cohort);
  75  
  76      $handler = core_cohort\customfield\cohort_handler::create();
  77      $handler->instance_form_save($cohort, true);
  78  
  79      $event = \core\event\cohort_created::create(array(
  80          'context' => context::instance_by_id($cohort->contextid),
  81          'objectid' => $cohort->id,
  82      ));
  83      $event->add_record_snapshot('cohort', $cohort);
  84      $event->trigger();
  85  
  86      return $cohort->id;
  87  }
  88  
  89  /**
  90   * Update existing cohort.
  91   * @param  stdClass $cohort
  92   * @return void
  93   */
  94  function cohort_update_cohort($cohort) {
  95      global $DB, $CFG;
  96      if (property_exists($cohort, 'component') and empty($cohort->component)) {
  97          // prevent NULLs
  98          $cohort->component = '';
  99      }
 100      // Only unset the cohort theme if allowcohortthemes is enabled to prevent the value from being overwritten.
 101      if (empty($CFG->allowcohortthemes) && isset($cohort->theme)) {
 102          unset($cohort->theme);
 103      }
 104      $cohort->timemodified = time();
 105  
 106      // Update custom fields if there are any of them in the form.
 107      $handler = core_cohort\customfield\cohort_handler::create();
 108      $handler->instance_form_save($cohort);
 109  
 110      $DB->update_record('cohort', $cohort);
 111  
 112      $event = \core\event\cohort_updated::create(array(
 113          'context' => context::instance_by_id($cohort->contextid),
 114          'objectid' => $cohort->id,
 115      ));
 116      $event->trigger();
 117  }
 118  
 119  /**
 120   * Delete cohort.
 121   * @param  stdClass $cohort
 122   * @return void
 123   */
 124  function cohort_delete_cohort($cohort) {
 125      global $DB;
 126  
 127      if ($cohort->component) {
 128          // TODO: add component delete callback
 129      }
 130  
 131      $handler = core_cohort\customfield\cohort_handler::create();
 132      $handler->delete_instance($cohort->id);
 133  
 134      $DB->delete_records('cohort_members', array('cohortid'=>$cohort->id));
 135      $DB->delete_records('cohort', array('id'=>$cohort->id));
 136  
 137      // Notify the competency subsystem.
 138      \core_competency\api::hook_cohort_deleted($cohort);
 139  
 140      $event = \core\event\cohort_deleted::create(array(
 141          'context' => context::instance_by_id($cohort->contextid),
 142          'objectid' => $cohort->id,
 143      ));
 144      $event->add_record_snapshot('cohort', $cohort);
 145      $event->trigger();
 146  }
 147  
 148  /**
 149   * Somehow deal with cohorts when deleting course category,
 150   * we can not just delete them because they might be used in enrol
 151   * plugins or referenced in external systems.
 152   * @param  stdClass|core_course_category $category
 153   * @return void
 154   */
 155  function cohort_delete_category($category) {
 156      global $DB;
 157      // TODO: make sure that cohorts are really, really not used anywhere and delete, for now just move to parent or system context
 158  
 159      $oldcontext = context_coursecat::instance($category->id);
 160  
 161      if ($category->parent and $parent = $DB->get_record('course_categories', array('id'=>$category->parent))) {
 162          $parentcontext = context_coursecat::instance($parent->id);
 163          $sql = "UPDATE {cohort} SET contextid = :newcontext WHERE contextid = :oldcontext";
 164          $params = array('oldcontext'=>$oldcontext->id, 'newcontext'=>$parentcontext->id);
 165      } else {
 166          $syscontext = context_system::instance();
 167          $sql = "UPDATE {cohort} SET contextid = :newcontext WHERE contextid = :oldcontext";
 168          $params = array('oldcontext'=>$oldcontext->id, 'newcontext'=>$syscontext->id);
 169      }
 170  
 171      $DB->execute($sql, $params);
 172  }
 173  
 174  /**
 175   * Add cohort member
 176   * @param  int $cohortid
 177   * @param  int $userid
 178   * @return void
 179   */
 180  function cohort_add_member($cohortid, $userid) {
 181      global $DB;
 182      if ($DB->record_exists('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid))) {
 183          // No duplicates!
 184          return;
 185      }
 186      $record = new stdClass();
 187      $record->cohortid  = $cohortid;
 188      $record->userid    = $userid;
 189      $record->timeadded = time();
 190      $DB->insert_record('cohort_members', $record);
 191  
 192      $cohort = $DB->get_record('cohort', array('id' => $cohortid), '*', MUST_EXIST);
 193  
 194      $event = \core\event\cohort_member_added::create(array(
 195          'context' => context::instance_by_id($cohort->contextid),
 196          'objectid' => $cohortid,
 197          'relateduserid' => $userid,
 198      ));
 199      $event->add_record_snapshot('cohort', $cohort);
 200      $event->trigger();
 201  }
 202  
 203  /**
 204   * Remove cohort member
 205   * @param  int $cohortid
 206   * @param  int $userid
 207   * @return void
 208   */
 209  function cohort_remove_member($cohortid, $userid) {
 210      global $DB;
 211      $DB->delete_records('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid));
 212  
 213      $cohort = $DB->get_record('cohort', array('id' => $cohortid), '*', MUST_EXIST);
 214  
 215      $event = \core\event\cohort_member_removed::create(array(
 216          'context' => context::instance_by_id($cohort->contextid),
 217          'objectid' => $cohortid,
 218          'relateduserid' => $userid,
 219      ));
 220      $event->add_record_snapshot('cohort', $cohort);
 221      $event->trigger();
 222  }
 223  
 224  /**
 225   * Is this user a cohort member?
 226   * @param int $cohortid
 227   * @param int $userid
 228   * @return bool
 229   */
 230  function cohort_is_member($cohortid, $userid) {
 231      global $DB;
 232  
 233      return $DB->record_exists('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid));
 234  }
 235  
 236  /**
 237   * Returns the list of cohorts visible to the current user in the given course.
 238   *
 239   * The following fields are returned in each record: id, name, contextid, idnumber, visible
 240   * Fields memberscnt and enrolledcnt will be also returned if requested
 241   *
 242   * @param context $currentcontext
 243   * @param int $withmembers one of the COHORT_XXX constants that allows to return non empty cohorts only
 244   *      or cohorts with enroled/not enroled users, or just return members count
 245   * @param int $offset
 246   * @param int $limit
 247   * @param string $search
 248   * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 249   * @return array
 250   */
 251  function cohort_get_available_cohorts($currentcontext, $withmembers = 0, $offset = 0, $limit = 25,
 252          $search = '', $withcustomfields = false) {
 253      global $DB;
 254  
 255      $params = array();
 256  
 257      // Build context subquery. Find the list of parent context where user is able to see any or visible-only cohorts.
 258      // Since this method is normally called for the current course all parent contexts are already preloaded.
 259      $contextsany = array_filter($currentcontext->get_parent_context_ids(),
 260          function($a) {
 261              return has_capability("moodle/cohort:view", context::instance_by_id($a));
 262          });
 263      $contextsvisible = array_diff($currentcontext->get_parent_context_ids(), $contextsany);
 264      if (empty($contextsany) && empty($contextsvisible)) {
 265          // User does not have any permissions to view cohorts.
 266          return array();
 267      }
 268      $subqueries = array();
 269      if (!empty($contextsany)) {
 270          list($parentsql, $params1) = $DB->get_in_or_equal($contextsany, SQL_PARAMS_NAMED, 'ctxa');
 271          $subqueries[] = 'c.contextid ' . $parentsql;
 272          $params = array_merge($params, $params1);
 273      }
 274      if (!empty($contextsvisible)) {
 275          list($parentsql, $params1) = $DB->get_in_or_equal($contextsvisible, SQL_PARAMS_NAMED, 'ctxv');
 276          $subqueries[] = '(c.visible = 1 AND c.contextid ' . $parentsql. ')';
 277          $params = array_merge($params, $params1);
 278      }
 279      $wheresql = '(' . implode(' OR ', $subqueries) . ')';
 280  
 281      // Build the rest of the query.
 282      $fromsql = "";
 283      $fieldssql = 'c.id, c.name, c.contextid, c.idnumber, c.visible';
 284      $groupbysql = '';
 285      $havingsql = '';
 286      if ($withmembers) {
 287          $fieldssql .= ', s.memberscnt';
 288          $subfields = "c.id, COUNT(DISTINCT cm.userid) AS memberscnt";
 289          $groupbysql = " GROUP BY c.id";
 290          $fromsql = " LEFT JOIN {cohort_members} cm ON cm.cohortid = c.id ";
 291          if (in_array($withmembers,
 292                  array(COHORT_COUNT_ENROLLED_MEMBERS, COHORT_WITH_ENROLLED_MEMBERS_ONLY, COHORT_WITH_NOTENROLLED_MEMBERS_ONLY))) {
 293              list($esql, $params2) = get_enrolled_sql($currentcontext);
 294              $fromsql .= " LEFT JOIN ($esql) u ON u.id = cm.userid ";
 295              $params = array_merge($params2, $params);
 296              $fieldssql .= ', s.enrolledcnt';
 297              $subfields .= ', COUNT(DISTINCT u.id) AS enrolledcnt';
 298          }
 299          if ($withmembers == COHORT_WITH_MEMBERS_ONLY) {
 300              $havingsql = " HAVING COUNT(DISTINCT cm.userid) > 0";
 301          } else if ($withmembers == COHORT_WITH_ENROLLED_MEMBERS_ONLY) {
 302              $havingsql = " HAVING COUNT(DISTINCT u.id) > 0";
 303          } else if ($withmembers == COHORT_WITH_NOTENROLLED_MEMBERS_ONLY) {
 304              $havingsql = " HAVING COUNT(DISTINCT cm.userid) > COUNT(DISTINCT u.id)";
 305          }
 306      }
 307      if ($search) {
 308          list($searchsql, $searchparams) = cohort_get_search_query($search);
 309          $wheresql .= ' AND ' . $searchsql;
 310          $params = array_merge($params, $searchparams);
 311      }
 312  
 313      if ($withmembers) {
 314          $sql = "SELECT " . str_replace('c.', 'cohort.', $fieldssql) . "
 315                    FROM {cohort} cohort
 316                    JOIN (SELECT $subfields
 317                            FROM {cohort} c $fromsql
 318                           WHERE $wheresql $groupbysql $havingsql
 319                          ) s ON cohort.id = s.id
 320                ORDER BY cohort.name, cohort.idnumber";
 321      } else {
 322          $sql = "SELECT $fieldssql
 323                    FROM {cohort} c $fromsql
 324                   WHERE $wheresql
 325                ORDER BY c.name, c.idnumber";
 326      }
 327  
 328      $cohorts = $DB->get_records_sql($sql, $params, $offset, $limit);
 329  
 330      if ($withcustomfields) {
 331          $cohortids = array_keys($cohorts);
 332          $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 333  
 334          foreach ($cohorts as $cohort) {
 335              $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 336          }
 337      }
 338  
 339      return $cohorts;
 340  }
 341  
 342  /**
 343   * Check if cohort exists and user is allowed to access it from the given context.
 344   *
 345   * @param stdClass|int $cohortorid cohort object or id
 346   * @param context $currentcontext current context (course) where visibility is checked
 347   * @return boolean
 348   */
 349  function cohort_can_view_cohort($cohortorid, $currentcontext) {
 350      global $DB;
 351      if (is_numeric($cohortorid)) {
 352          $cohort = $DB->get_record('cohort', array('id' => $cohortorid), 'id, contextid, visible');
 353      } else {
 354          $cohort = $cohortorid;
 355      }
 356  
 357      if ($cohort && in_array($cohort->contextid, $currentcontext->get_parent_context_ids())) {
 358          if ($cohort->visible) {
 359              return true;
 360          }
 361          $cohortcontext = context::instance_by_id($cohort->contextid);
 362          if (has_capability('moodle/cohort:view', $cohortcontext)) {
 363              return true;
 364          }
 365      }
 366      return false;
 367  }
 368  
 369  /**
 370   * Get a cohort by id. Also does a visibility check and returns false if the user cannot see this cohort.
 371   *
 372   * @param stdClass|int $cohortorid cohort object or id
 373   * @param context $currentcontext current context (course) where visibility is checked
 374   * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 375   * @return stdClass|boolean
 376   */
 377  function cohort_get_cohort($cohortorid, $currentcontext, $withcustomfields = false) {
 378      global $DB;
 379      if (is_numeric($cohortorid)) {
 380          $cohort = $DB->get_record('cohort', array('id' => $cohortorid), 'id, contextid, visible');
 381      } else {
 382          $cohort = $cohortorid;
 383      }
 384  
 385      if ($cohort && in_array($cohort->contextid, $currentcontext->get_parent_context_ids())) {
 386          if (!$cohort->visible) {
 387              $cohortcontext = context::instance_by_id($cohort->contextid);
 388              if (!has_capability('moodle/cohort:view', $cohortcontext)) {
 389                  return false;
 390              }
 391          }
 392      } else {
 393          return false;
 394      }
 395  
 396      if ($cohort && $withcustomfields) {
 397          $customfieldsdata = cohort_get_custom_fields_data([$cohort->id]);
 398          $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 399      }
 400  
 401      return $cohort;
 402  }
 403  
 404  /**
 405   * Produces a part of SQL query to filter cohorts by the search string
 406   *
 407   * Called from {@link cohort_get_cohorts()}, {@link cohort_get_all_cohorts()} and {@link cohort_get_available_cohorts()}
 408   *
 409   * @access private
 410   *
 411   * @param string $search search string
 412   * @param string $tablealias alias of cohort table in the SQL query (highly recommended if other tables are used in query)
 413   * @return array of two elements - SQL condition and array of named parameters
 414   */
 415  function cohort_get_search_query($search, $tablealias = '') {
 416      global $DB;
 417      $params = array();
 418      if (empty($search)) {
 419          // This function should not be called if there is no search string, just in case return dummy query.
 420          return array('1=1', $params);
 421      }
 422      if ($tablealias && substr($tablealias, -1) !== '.') {
 423          $tablealias .= '.';
 424      }
 425      $searchparam = '%' . $DB->sql_like_escape($search) . '%';
 426      $conditions = array();
 427      $fields = array('name', 'idnumber', 'description');
 428      $cnt = 0;
 429      foreach ($fields as $field) {
 430          $conditions[] = $DB->sql_like($tablealias . $field, ':csearch' . $cnt, false);
 431          $params['csearch' . $cnt] = $searchparam;
 432          $cnt++;
 433      }
 434      $sql = '(' . implode(' OR ', $conditions) . ')';
 435      return array($sql, $params);
 436  }
 437  
 438  /**
 439   * Get all the cohorts defined in given context.
 440   *
 441   * The function does not check user capability to view/manage cohorts in the given context
 442   * assuming that it has been already verified.
 443   *
 444   * @param int $contextid
 445   * @param int $page number of the current page
 446   * @param int $perpage items per page
 447   * @param string $search search string
 448   * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 449   * @return array    Array(totalcohorts => int, cohorts => array, allcohorts => int)
 450   */
 451  function cohort_get_cohorts($contextid, $page = 0, $perpage = 25, $search = '', $withcustomfields = false) {
 452      global $DB;
 453  
 454      $fields = "SELECT *";
 455      $countfields = "SELECT COUNT(1)";
 456      $sql = " FROM {cohort}
 457               WHERE contextid = :contextid";
 458      $params = array('contextid' => $contextid);
 459      $order = " ORDER BY name ASC, idnumber ASC";
 460  
 461      if (!empty($search)) {
 462          list($searchcondition, $searchparams) = cohort_get_search_query($search);
 463          $sql .= ' AND ' . $searchcondition;
 464          $params = array_merge($params, $searchparams);
 465      }
 466  
 467      $totalcohorts = $allcohorts = $DB->count_records('cohort', array('contextid' => $contextid));
 468      if (!empty($search)) {
 469          $totalcohorts = $DB->count_records_sql($countfields . $sql, $params);
 470      }
 471      $cohorts = $DB->get_records_sql($fields . $sql . $order, $params, $page*$perpage, $perpage);
 472  
 473      if ($withcustomfields) {
 474          $cohortids = array_keys($cohorts);
 475          $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 476  
 477          foreach ($cohorts as $cohort) {
 478              $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 479          }
 480      }
 481  
 482      return array('totalcohorts' => $totalcohorts, 'cohorts' => $cohorts, 'allcohorts' => $allcohorts);
 483  }
 484  
 485  /**
 486   * Get all the cohorts defined anywhere in system.
 487   *
 488   * The function assumes that user capability to view/manage cohorts on system level
 489   * has already been verified. This function only checks if such capabilities have been
 490   * revoked in child (categories) contexts.
 491   *
 492   * @param int $page number of the current page
 493   * @param int $perpage items per page
 494   * @param string $search search string
 495   * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 496   * @return array    Array(totalcohorts => int, cohorts => array, allcohorts => int)
 497   */
 498  function cohort_get_all_cohorts($page = 0, $perpage = 25, $search = '', $withcustomfields = false) {
 499      global $DB;
 500  
 501      $fields = "SELECT c.*, ".context_helper::get_preload_record_columns_sql('ctx');
 502      $countfields = "SELECT COUNT(*)";
 503      $sql = " FROM {cohort} c
 504               JOIN {context} ctx ON ctx.id = c.contextid ";
 505      $params = array();
 506      $wheresql = '';
 507  
 508      if ($excludedcontexts = cohort_get_invisible_contexts()) {
 509          list($excludedsql, $excludedparams) = $DB->get_in_or_equal($excludedcontexts, SQL_PARAMS_NAMED, 'excl', false);
 510          $wheresql = ' WHERE c.contextid '.$excludedsql;
 511          $params = array_merge($params, $excludedparams);
 512      }
 513  
 514      $totalcohorts = $allcohorts = $DB->count_records_sql($countfields . $sql . $wheresql, $params);
 515  
 516      if (!empty($search)) {
 517          list($searchcondition, $searchparams) = cohort_get_search_query($search, 'c');
 518          $wheresql .= ($wheresql ? ' AND ' : ' WHERE ') . $searchcondition;
 519          $params = array_merge($params, $searchparams);
 520          $totalcohorts = $DB->count_records_sql($countfields . $sql . $wheresql, $params);
 521      }
 522  
 523      $order = " ORDER BY c.name ASC, c.idnumber ASC";
 524      $cohorts = $DB->get_records_sql($fields . $sql . $wheresql . $order, $params, $page*$perpage, $perpage);
 525  
 526      if ($withcustomfields) {
 527          $cohortids = array_keys($cohorts);
 528          $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 529      }
 530  
 531      foreach ($cohorts as $cohort) {
 532          // Preload used contexts, they will be used to check view/manage/assign capabilities and display categories names.
 533          context_helper::preload_from_record($cohort);
 534          if ($withcustomfields) {
 535              $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 536          }
 537      }
 538  
 539      return array('totalcohorts' => $totalcohorts, 'cohorts' => $cohorts, 'allcohorts' => $allcohorts);
 540  }
 541  
 542  /**
 543   * Get all the cohorts where the given user is member of.
 544   *
 545   * @param int $userid
 546   * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 547   * @return array Array
 548   */
 549  function cohort_get_user_cohorts($userid, $withcustomfields = false) {
 550      global $DB;
 551  
 552      $sql = 'SELECT c.*
 553                FROM {cohort} c
 554                JOIN {cohort_members} cm ON c.id = cm.cohortid
 555               WHERE cm.userid = ? AND c.visible = 1';
 556      $cohorts = $DB->get_records_sql($sql, array($userid));
 557  
 558      if ($withcustomfields) {
 559          $cohortids = array_keys($cohorts);
 560          $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 561  
 562          foreach ($cohorts as $cohort) {
 563              $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 564          }
 565      }
 566  
 567      return $cohorts;
 568  }
 569  
 570  /**
 571   * Get the user cohort theme.
 572   *
 573   * If the user is member of one cohort, will return this cohort theme (if defined).
 574   * If the user is member of 2 or more cohorts, will return the theme if all them have the same
 575   * theme (null themes are ignored).
 576   *
 577   * @param int $userid
 578   * @return string|null
 579   */
 580  function cohort_get_user_cohort_theme($userid) {
 581      $cohorts = cohort_get_user_cohorts($userid);
 582      $theme = null;
 583      foreach ($cohorts as $cohort) {
 584          if (!empty($cohort->theme)) {
 585              if (null === $theme) {
 586                  $theme = $cohort->theme;
 587              } else if ($theme != $cohort->theme) {
 588                  return null;
 589              }
 590          }
 591      }
 592      return $theme;
 593  }
 594  
 595  /**
 596   * Returns list of contexts where cohorts are present but current user does not have capability to view/manage them.
 597   *
 598   * This function is called from {@link cohort_get_all_cohorts()} to ensure correct pagination in rare cases when user
 599   * is revoked capability in child contexts. It assumes that user's capability to view/manage cohorts on system
 600   * level has already been verified.
 601   *
 602   * @access private
 603   *
 604   * @return array array of context ids
 605   */
 606  function cohort_get_invisible_contexts() {
 607      global $DB;
 608      if (is_siteadmin()) {
 609          // Shortcut, admin can do anything and can not be prohibited from any context.
 610          return array();
 611      }
 612      $records = $DB->get_recordset_sql("SELECT DISTINCT ctx.id, ".context_helper::get_preload_record_columns_sql('ctx')." ".
 613          "FROM {context} ctx JOIN {cohort} c ON ctx.id = c.contextid ");
 614      $excludedcontexts = array();
 615      foreach ($records as $ctx) {
 616          context_helper::preload_from_record($ctx);
 617          if (context::instance_by_id($ctx->id) == context_system::instance()) {
 618              continue; // System context cohorts should be available and permissions already checked.
 619          }
 620          if (!has_any_capability(array('moodle/cohort:manage', 'moodle/cohort:view'), context::instance_by_id($ctx->id))) {
 621              $excludedcontexts[] = $ctx->id;
 622          }
 623      }
 624      $records->close();
 625      return $excludedcontexts;
 626  }
 627  
 628  /**
 629   * Returns navigation controls (tabtree) to be displayed on cohort management pages
 630   *
 631   * @param context $context system or category context where cohorts controls are about to be displayed
 632   * @param moodle_url $currenturl
 633   * @return null|renderable
 634   */
 635  function cohort_edit_controls(context $context, moodle_url $currenturl) {
 636      $tabs = array();
 637      $currenttab = 'view';
 638      $viewurl = new moodle_url('/cohort/index.php', array('contextid' => $context->id));
 639      if (($searchquery = $currenturl->get_param('search'))) {
 640          $viewurl->param('search', $searchquery);
 641      }
 642      if ($context->contextlevel == CONTEXT_SYSTEM) {
 643          $tabs[] = new tabobject('view', new moodle_url($viewurl, array('showall' => 0)), get_string('systemcohorts', 'cohort'));
 644          $tabs[] = new tabobject('viewall', new moodle_url($viewurl, array('showall' => 1)), get_string('allcohorts', 'cohort'));
 645          if ($currenturl->get_param('showall')) {
 646              $currenttab = 'viewall';
 647          }
 648      } else {
 649          $tabs[] = new tabobject('view', $viewurl, get_string('cohorts', 'cohort'));
 650      }
 651      if (has_capability('moodle/cohort:manage', $context)) {
 652          $addurl = new moodle_url('/cohort/edit.php', array('contextid' => $context->id));
 653          $tabs[] = new tabobject('addcohort', $addurl, get_string('addcohort', 'cohort'));
 654          if ($currenturl->get_path() === $addurl->get_path() && !$currenturl->param('id')) {
 655              $currenttab = 'addcohort';
 656          }
 657  
 658          $uploadurl = new moodle_url('/cohort/upload.php', array('contextid' => $context->id));
 659          $tabs[] = new tabobject('uploadcohorts', $uploadurl, get_string('uploadcohorts', 'cohort'));
 660          if ($currenturl->get_path() === $uploadurl->get_path()) {
 661              $currenttab = 'uploadcohorts';
 662          }
 663      }
 664      if (count($tabs) > 1) {
 665          return new tabtree($tabs, $currenttab);
 666      }
 667      return null;
 668  }
 669  
 670  /**
 671   * Implements callback inplace_editable() allowing to edit values in-place
 672   *
 673   * @param string $itemtype
 674   * @param int $itemid
 675   * @param mixed $newvalue
 676   * @return \core\output\inplace_editable
 677   */
 678  function core_cohort_inplace_editable($itemtype, $itemid, $newvalue) {
 679      if ($itemtype === 'cohortname') {
 680          return \core_cohort\output\cohortname::update($itemid, $newvalue);
 681      } else if ($itemtype === 'cohortidnumber') {
 682          return \core_cohort\output\cohortidnumber::update($itemid, $newvalue);
 683      }
 684  }
 685  
 686  /**
 687   * Returns a list of valid themes which can be displayed in a selector.
 688   *
 689   * @return array as (string)themename => (string)get_string_theme
 690   */
 691  function cohort_get_list_of_themes() {
 692      $themes = array();
 693      $allthemes = get_list_of_themes();
 694      foreach ($allthemes as $key => $theme) {
 695          if (empty($theme->hidefromselector)) {
 696              $themes[$key] = get_string('pluginname', 'theme_'.$theme->name);
 697          }
 698      }
 699      return $themes;
 700  }
 701  
 702  /**
 703   * Returns custom fields data for provided cohorts.
 704   *
 705   * @param array $cohortids a list of cohort IDs to provide data for.
 706   * @return \core_customfield\data_controller[]
 707   */
 708  function cohort_get_custom_fields_data(array $cohortids): array {
 709      $result = [];
 710  
 711      if (!empty($cohortids)) {
 712          $handler = core_cohort\customfield\cohort_handler::create();
 713          $result = $handler->get_instances_data($cohortids, true);
 714      }
 715  
 716      return $result;
 717  }