cohort/lib.php

   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
 105     // Delete theme usage cache if the theme has been changed.
 106     if (isset($cohort->theme)) {
 107         $oldcohort = $DB->get_record('cohort', ['id' => $cohort->id]);
 108         if ($cohort->theme != $oldcohort->theme) {
 109             theme_delete_used_in_context_cache($cohort->theme, $oldcohort->theme);
 110         }
 111     }
 112
 113     $cohort->timemodified = time();
 114
 115     // Update custom fields if there are any of them in the form.
 116     $handler = core_cohort\customfield\cohort_handler::create();
 117     $handler->instance_form_save($cohort);
 118
 119     $DB->update_record('cohort', $cohort);
 120
 121     $event = \core\event\cohort_updated::create(array(
 122         'context' => context::instance_by_id($cohort->contextid),
 123         'objectid' => $cohort->id,
 124     ));
 125     $event->trigger();
 126 }
 127
 128 /**
 129  * Delete cohort.
 130  * @param  stdClass $cohort
 131  * @return void
 132  */
 133 function cohort_delete_cohort($cohort) {
 134     global $DB;
 135
 136     if ($cohort->component) {
 137         // TODO: add component delete callback
 138     }
 139
 140     $handler = core_cohort\customfield\cohort_handler::create();
 141     $handler->delete_instance($cohort->id);
 142
 143     $DB->delete_records('cohort_members', array('cohortid'=>$cohort->id));
 144     $DB->delete_records('cohort', array('id'=>$cohort->id));
 145
 146     // Notify the competency subsystem.
 147     \core_competency\api::hook_cohort_deleted($cohort);
 148
 149     $event = \core\event\cohort_deleted::create(array(
 150         'context' => context::instance_by_id($cohort->contextid),
 151         'objectid' => $cohort->id,
 152     ));
 153     $event->add_record_snapshot('cohort', $cohort);
 154     $event->trigger();
 155 }
 156
 157 /**
 158  * Somehow deal with cohorts when deleting course category,
 159  * we can not just delete them because they might be used in enrol
 160  * plugins or referenced in external systems.
 161  * @param  stdClass|core_course_category $category
 162  * @return void
 163  */
 164 function cohort_delete_category($category) {
 165     global $DB;
 166     // TODO: make sure that cohorts are really, really not used anywhere and delete, for now just move to parent or system context
 167
 168     $oldcontext = context_coursecat::instance($category->id);
 169
 170     if ($category->parent and $parent = $DB->get_record('course_categories', array('id'=>$category->parent))) {
 171         $parentcontext = context_coursecat::instance($parent->id);
 172         $sql = "UPDATE {cohort} SET contextid = :newcontext WHERE contextid = :oldcontext";
 173         $params = array('oldcontext'=>$oldcontext->id, 'newcontext'=>$parentcontext->id);
 174     } else {
 175         $syscontext = context_system::instance();
 176         $sql = "UPDATE {cohort} SET contextid = :newcontext WHERE contextid = :oldcontext";
 177         $params = array('oldcontext'=>$oldcontext->id, 'newcontext'=>$syscontext->id);
 178     }
 179
 180     $DB->execute($sql, $params);
 181 }
 182
 183 /**
 184  * Add cohort member
 185  * @param  int $cohortid
 186  * @param  int $userid
 187  * @return void
 188  */
 189 function cohort_add_member($cohortid, $userid) {
 190     global $DB;
 191     if ($DB->record_exists('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid))) {
 192         // No duplicates!
 193         return;
 194     }
 195     $record = new stdClass();
 196     $record->cohortid  = $cohortid;
 197     $record->userid    = $userid;
 198     $record->timeadded = time();
 199     $DB->insert_record('cohort_members', $record);
 200
 201     $cohort = $DB->get_record('cohort', array('id' => $cohortid), '*', MUST_EXIST);
 202
 203     $event = \core\event\cohort_member_added::create(array(
 204         'context' => context::instance_by_id($cohort->contextid),
 205         'objectid' => $cohortid,
 206         'relateduserid' => $userid,
 207     ));
 208     $event->add_record_snapshot('cohort', $cohort);
 209     $event->trigger();
 210 }
 211
 212 /**
 213  * Remove cohort member
 214  * @param  int $cohortid
 215  * @param  int $userid
 216  * @return void
 217  */
 218 function cohort_remove_member($cohortid, $userid) {
 219     global $DB;
 220     $DB->delete_records('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid));
 221
 222     $cohort = $DB->get_record('cohort', array('id' => $cohortid), '*', MUST_EXIST);
 223
 224     $event = \core\event\cohort_member_removed::create(array(
 225         'context' => context::instance_by_id($cohort->contextid),
 226         'objectid' => $cohortid,
 227         'relateduserid' => $userid,
 228     ));
 229     $event->add_record_snapshot('cohort', $cohort);
 230     $event->trigger();
 231 }
 232
 233 /**
 234  * Is this user a cohort member?
 235  * @param int $cohortid
 236  * @param int $userid
 237  * @return bool
 238  */
 239 function cohort_is_member($cohortid, $userid) {
 240     global $DB;
 241
 242     return $DB->record_exists('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid));
 243 }
 244
 245 /**
 246  * Returns the list of cohorts visible to the current user in the given course.
 247  *
 248  * The following fields are returned in each record: id, name, contextid, idnumber, visible
 249  * Fields memberscnt and enrolledcnt will be also returned if requested
 250  *
 251  * @param context $currentcontext
 252  * @param int $withmembers one of the COHORT_XXX constants that allows to return non empty cohorts only
 253  *      or cohorts with enroled/not enroled users, or just return members count
 254  * @param int $offset
 255  * @param int $limit
 256  * @param string $search
 257  * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 258  * @return array
 259  */
 260 function cohort_get_available_cohorts($currentcontext, $withmembers = 0, $offset = 0, $limit = 25,
 261         $search = '', $withcustomfields = false) {
 262     global $DB;
 263
 264     $params = array();
 265
 266     // Build context subquery. Find the list of parent context where user is able to see any or visible-only cohorts.
 267     // Since this method is normally called for the current course all parent contexts are already preloaded.
 268     $contextsany = array_filter($currentcontext->get_parent_context_ids(),
 269         function($a) {
 270             return has_capability("moodle/cohort:view", context::instance_by_id($a));
 271         });
 272     $contextsvisible = array_diff($currentcontext->get_parent_context_ids(), $contextsany);
 273     if (empty($contextsany) && empty($contextsvisible)) {
 274         // User does not have any permissions to view cohorts.
 275         return array();
 276     }
 277     $subqueries = array();
 278     if (!empty($contextsany)) {
 279         list($parentsql, $params1) = $DB->get_in_or_equal($contextsany, SQL_PARAMS_NAMED, 'ctxa');
 280         $subqueries[] = 'c.contextid ' . $parentsql;
 281         $params = array_merge($params, $params1);
 282     }
 283     if (!empty($contextsvisible)) {
 284         list($parentsql, $params1) = $DB->get_in_or_equal($contextsvisible, SQL_PARAMS_NAMED, 'ctxv');
 285         $subqueries[] = '(c.visible = 1 AND c.contextid ' . $parentsql. ')';
 286         $params = array_merge($params, $params1);
 287     }
 288     $wheresql = '(' . implode(' OR ', $subqueries) . ')';
 289
 290     // Build the rest of the query.
 291     $fromsql = "";
 292     $fieldssql = 'c.id, c.name, c.contextid, c.idnumber, c.visible';
 293     $groupbysql = '';
 294     $havingsql = '';
 295     if ($withmembers) {
 296         $fieldssql .= ', s.memberscnt';
 297         $subfields = "c.id, COUNT(DISTINCT cm.userid) AS memberscnt";
 298         $groupbysql = " GROUP BY c.id";
 299         $fromsql = " LEFT JOIN {cohort_members} cm ON cm.cohortid = c.id ";
 300         if (in_array($withmembers,
 301                 array(COHORT_COUNT_ENROLLED_MEMBERS, COHORT_WITH_ENROLLED_MEMBERS_ONLY, COHORT_WITH_NOTENROLLED_MEMBERS_ONLY))) {
 302             list($esql, $params2) = get_enrolled_sql($currentcontext);
 303             $fromsql .= " LEFT JOIN ($esql) u ON u.id = cm.userid ";
 304             $params = array_merge($params2, $params);
 305             $fieldssql .= ', s.enrolledcnt';
 306             $subfields .= ', COUNT(DISTINCT u.id) AS enrolledcnt';
 307         }
 308         if ($withmembers == COHORT_WITH_MEMBERS_ONLY) {
 309             $havingsql = " HAVING COUNT(DISTINCT cm.userid) > 0";
 310         } else if ($withmembers == COHORT_WITH_ENROLLED_MEMBERS_ONLY) {
 311             $havingsql = " HAVING COUNT(DISTINCT u.id) > 0";
 312         } else if ($withmembers == COHORT_WITH_NOTENROLLED_MEMBERS_ONLY) {
 313             $havingsql = " HAVING COUNT(DISTINCT cm.userid) > COUNT(DISTINCT u.id)";
 314         }
 315     }
 316     if ($search) {
 317         list($searchsql, $searchparams) = cohort_get_search_query($search);
 318         $wheresql .= ' AND ' . $searchsql;
 319         $params = array_merge($params, $searchparams);
 320     }
 321
 322     if ($withmembers) {
 323         $sql = "SELECT " . str_replace('c.', 'cohort.', $fieldssql) . "
 324                   FROM {cohort} cohort
 325                   JOIN (SELECT $subfields
 326                           FROM {cohort} c $fromsql
 327                          WHERE $wheresql $groupbysql $havingsql
 328                         ) s ON cohort.id = s.id
 329               ORDER BY cohort.name, cohort.idnumber";
 330     } else {
 331         $sql = "SELECT $fieldssql
 332                   FROM {cohort} c $fromsql
 333                  WHERE $wheresql
 334               ORDER BY c.name, c.idnumber";
 335     }
 336
 337     $cohorts = $DB->get_records_sql($sql, $params, $offset, $limit);
 338
 339     if ($withcustomfields) {
 340         $cohortids = array_keys($cohorts);
 341         $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 342
 343         foreach ($cohorts as $cohort) {
 344             $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 345         }
 346     }
 347
 348     return $cohorts;
 349 }
 350
 351 /**
 352  * Check if cohort exists and user is allowed to access it from the given context.
 353  *
 354  * @param stdClass|int $cohortorid cohort object or id
 355  * @param context $currentcontext current context (course) where visibility is checked
 356  * @return boolean
 357  */
 358 function cohort_can_view_cohort($cohortorid, $currentcontext) {
 359     global $DB;
 360     if (is_numeric($cohortorid)) {
 361         $cohort = $DB->get_record('cohort', array('id' => $cohortorid), 'id, contextid, visible');
 362     } else {
 363         $cohort = $cohortorid;
 364     }
 365
 366     if ($cohort && in_array($cohort->contextid, $currentcontext->get_parent_context_ids())) {
 367         if ($cohort->visible) {
 368             return true;
 369         }
 370         $cohortcontext = context::instance_by_id($cohort->contextid);
 371         if (has_capability('moodle/cohort:view', $cohortcontext)) {
 372             return true;
 373         }
 374     }
 375     return false;
 376 }
 377
 378 /**
 379  * Get a cohort by id. Also does a visibility check and returns false if the user cannot see this cohort.
 380  *
 381  * @param stdClass|int $cohortorid cohort object or id
 382  * @param context $currentcontext current context (course) where visibility is checked
 383  * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 384  * @return stdClass|boolean
 385  */
 386 function cohort_get_cohort($cohortorid, $currentcontext, $withcustomfields = false) {
 387     global $DB;
 388     if (is_numeric($cohortorid)) {
 389         $cohort = $DB->get_record('cohort', array('id' => $cohortorid), 'id, contextid, visible');
 390     } else {
 391         $cohort = $cohortorid;
 392     }
 393
 394     if ($cohort && in_array($cohort->contextid, $currentcontext->get_parent_context_ids())) {
 395         if (!$cohort->visible) {
 396             $cohortcontext = context::instance_by_id($cohort->contextid);
 397             if (!has_capability('moodle/cohort:view', $cohortcontext)) {
 398                 return false;
 399             }
 400         }
 401     } else {
 402         return false;
 403     }
 404
 405     if ($cohort && $withcustomfields) {
 406         $customfieldsdata = cohort_get_custom_fields_data([$cohort->id]);
 407         $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 408     }
 409
 410     return $cohort;
 411 }
 412
 413 /**
 414  * Produces a part of SQL query to filter cohorts by the search string
 415  *
 416  * Called from {@link cohort_get_cohorts()}, {@link cohort_get_all_cohorts()} and {@link cohort_get_available_cohorts()}
 417  *
 418  * @access private
 419  *
 420  * @param string $search search string
 421  * @param string $tablealias alias of cohort table in the SQL query (highly recommended if other tables are used in query)
 422  * @return array of two elements - SQL condition and array of named parameters
 423  */
 424 function cohort_get_search_query($search, $tablealias = '') {
 425     global $DB;
 426     $params = array();
 427     if (empty($search)) {
 428         // This function should not be called if there is no search string, just in case return dummy query.
 429         return array('1=1', $params);
 430     }
 431     if ($tablealias && substr($tablealias, -1) !== '.') {
 432         $tablealias .= '.';
 433     }
 434     $searchparam = '%' . $DB->sql_like_escape($search) . '%';
 435     $conditions = array();
 436     $fields = array('name', 'idnumber', 'description');
 437     $cnt = 0;
 438     foreach ($fields as $field) {
 439         $conditions[] = $DB->sql_like($tablealias . $field, ':csearch' . $cnt, false);
 440         $params['csearch' . $cnt] = $searchparam;
 441         $cnt++;
 442     }
 443     $sql = '(' . implode(' OR ', $conditions) . ')';
 444     return array($sql, $params);
 445 }
 446
 447 /**
 448  * Get all the cohorts defined in given context.
 449  *
 450  * The function does not check user capability to view/manage cohorts in the given context
 451  * assuming that it has been already verified.
 452  *
 453  * @param int $contextid
 454  * @param int $page number of the current page
 455  * @param int $perpage items per page
 456  * @param string $search search string
 457  * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 458  * @return array    Array(totalcohorts => int, cohorts => array, allcohorts => int)
 459  */
 460 function cohort_get_cohorts($contextid, $page = 0, $perpage = 25, $search = '', $withcustomfields = false) {
 461     global $DB;
 462
 463     $fields = "SELECT *";
 464     $countfields = "SELECT COUNT(1)";
 465     $sql = " FROM {cohort}
 466              WHERE contextid = :contextid";
 467     $params = array('contextid' => $contextid);
 468     $order = " ORDER BY name ASC, idnumber ASC";
 469
 470     if (!empty($search)) {
 471         list($searchcondition, $searchparams) = cohort_get_search_query($search);
 472         $sql .= ' AND ' . $searchcondition;
 473         $params = array_merge($params, $searchparams);
 474     }
 475
 476     $totalcohorts = $allcohorts = $DB->count_records('cohort', array('contextid' => $contextid));
 477     if (!empty($search)) {
 478         $totalcohorts = $DB->count_records_sql($countfields . $sql, $params);
 479     }
 480     $cohorts = $DB->get_records_sql($fields . $sql . $order, $params, $page*$perpage, $perpage);
 481
 482     if ($withcustomfields) {
 483         $cohortids = array_keys($cohorts);
 484         $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 485
 486         foreach ($cohorts as $cohort) {
 487             $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 488         }
 489     }
 490
 491     return array('totalcohorts' => $totalcohorts, 'cohorts' => $cohorts, 'allcohorts' => $allcohorts);
 492 }
 493
 494 /**
 495  * Get all the cohorts defined anywhere in system.
 496  *
 497  * The function assumes that user capability to view/manage cohorts on system level
 498  * has already been verified. This function only checks if such capabilities have been
 499  * revoked in child (categories) contexts.
 500  *
 501  * @param int $page number of the current page
 502  * @param int $perpage items per page
 503  * @param string $search search string
 504  * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 505  * @return array    Array(totalcohorts => int, cohorts => array, allcohorts => int)
 506  */
 507 function cohort_get_all_cohorts($page = 0, $perpage = 25, $search = '', $withcustomfields = false) {
 508     global $DB;
 509
 510     $fields = "SELECT c.*, ".context_helper::get_preload_record_columns_sql('ctx');
 511     $countfields = "SELECT COUNT(*)";
 512     $sql = " FROM {cohort} c
 513              JOIN {context} ctx ON ctx.id = c.contextid ";
 514     $params = array();
 515     $wheresql = '';
 516
 517     if ($excludedcontexts = cohort_get_invisible_contexts()) {
 518         list($excludedsql, $excludedparams) = $DB->get_in_or_equal($excludedcontexts, SQL_PARAMS_NAMED, 'excl', false);
 519         $wheresql = ' WHERE c.contextid '.$excludedsql;
 520         $params = array_merge($params, $excludedparams);
 521     }
 522
 523     $totalcohorts = $allcohorts = $DB->count_records_sql($countfields . $sql . $wheresql, $params);
 524
 525     if (!empty($search)) {
 526         list($searchcondition, $searchparams) = cohort_get_search_query($search, 'c');
 527         $wheresql .= ($wheresql ? ' AND ' : ' WHERE ') . $searchcondition;
 528         $params = array_merge($params, $searchparams);
 529         $totalcohorts = $DB->count_records_sql($countfields . $sql . $wheresql, $params);
 530     }
 531
 532     $order = " ORDER BY c.name ASC, c.idnumber ASC";
 533     $cohorts = $DB->get_records_sql($fields . $sql . $wheresql . $order, $params, $page*$perpage, $perpage);
 534
 535     if ($withcustomfields) {
 536         $cohortids = array_keys($cohorts);
 537         $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 538     }
 539
 540     foreach ($cohorts as $cohort) {
 541         // Preload used contexts, they will be used to check view/manage/assign capabilities and display categories names.
 542         context_helper::preload_from_record($cohort);
 543         if ($withcustomfields) {
 544             $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 545         }
 546     }
 547
 548     return array('totalcohorts' => $totalcohorts, 'cohorts' => $cohorts, 'allcohorts' => $allcohorts);
 549 }
 550
 551 /**
 552  * Get all the cohorts where the given user is member of.
 553  *
 554  * @param int $userid
 555  * @param bool $withcustomfields if set to yes, then cohort custom fields will be included in the results.
 556  * @return array Array
 557  */
 558 function cohort_get_user_cohorts($userid, $withcustomfields = false) {
 559     global $DB;
 560
 561     $sql = 'SELECT c.*
 562               FROM {cohort} c
 563               JOIN {cohort_members} cm ON c.id = cm.cohortid
 564              WHERE cm.userid = ? AND c.visible = 1';
 565     $cohorts = $DB->get_records_sql($sql, array($userid));
 566
 567     if ($withcustomfields) {
 568         $cohortids = array_keys($cohorts);
 569         $customfieldsdata = cohort_get_custom_fields_data($cohortids);
 570
 571         foreach ($cohorts as $cohort) {
 572             $cohort->customfields = !empty($customfieldsdata[$cohort->id]) ? $customfieldsdata[$cohort->id] : [];
 573         }
 574     }
 575
 576     return $cohorts;
 577 }
 578
 579 /**
 580  * Get the user cohort theme.
 581  *
 582  * If the user is member of one cohort, will return this cohort theme (if defined).
 583  * If the user is member of 2 or more cohorts, will return the theme if all them have the same
 584  * theme (null themes are ignored).
 585  *
 586  * @param int $userid
 587  * @return string|null
 588  */
 589 function cohort_get_user_cohort_theme($userid) {
 590     $cohorts = cohort_get_user_cohorts($userid);
 591     $theme = null;
 592     foreach ($cohorts as $cohort) {
 593         if (!empty($cohort->theme)) {
 594             if (null === $theme) {
 595                 $theme = $cohort->theme;
 596             } else if ($theme != $cohort->theme) {
 597                 return null;
 598             }
 599         }
 600     }
 601     return $theme;
 602 }
 603
 604 /**
 605  * Returns list of contexts where cohorts are present but current user does not have capability to view/manage them.
 606  *
 607  * This function is called from {@link cohort_get_all_cohorts()} to ensure correct pagination in rare cases when user
 608  * is revoked capability in child contexts. It assumes that user's capability to view/manage cohorts on system
 609  * level has already been verified.
 610  *
 611  * @access private
 612  *
 613  * @return array array of context ids
 614  */
 615 function cohort_get_invisible_contexts() {
 616     global $DB;
 617     if (is_siteadmin()) {
 618         // Shortcut, admin can do anything and can not be prohibited from any context.
 619         return array();
 620     }
 621     $records = $DB->get_recordset_sql("SELECT DISTINCT ctx.id, ".context_helper::get_preload_record_columns_sql('ctx')." ".
 622         "FROM {context} ctx JOIN {cohort} c ON ctx.id = c.contextid ");
 623     $excludedcontexts = array();
 624     foreach ($records as $ctx) {
 625         context_helper::preload_from_record($ctx);
 626         if (context::instance_by_id($ctx->id) == context_system::instance()) {
 627             continue; // System context cohorts should be available and permissions already checked.
 628         }
 629         if (!has_any_capability(array('moodle/cohort:manage', 'moodle/cohort:view'), context::instance_by_id($ctx->id))) {
 630             $excludedcontexts[] = $ctx->id;
 631         }
 632     }
 633     $records->close();
 634     return $excludedcontexts;
 635 }
 636
 637 /**
 638  * Returns navigation controls (tabtree) to be displayed on cohort management pages
 639  *
 640  * @param context $context system or category context where cohorts controls are about to be displayed
 641  * @param moodle_url $currenturl
 642  * @return null|renderable
 643  */
 644 function cohort_edit_controls(context $context, moodle_url $currenturl) {
 645     $tabs = array();
 646     $currenttab = 'view';
 647     $viewurl = new moodle_url('/cohort/index.php', array('contextid' => $context->id));
 648     if (($searchquery = $currenturl->get_param('search'))) {
 649         $viewurl->param('search', $searchquery);
 650     }
 651     if ($context->contextlevel == CONTEXT_SYSTEM) {
 652         $tabs[] = new tabobject('view', new moodle_url($viewurl, array('showall' => 0)), get_string('systemcohorts', 'cohort'));
 653         $tabs[] = new tabobject('viewall', new moodle_url($viewurl, array('showall' => 1)), get_string('allcohorts', 'cohort'));
 654         if ($currenturl->get_param('showall')) {
 655             $currenttab = 'viewall';
 656         }
 657     } else {
 658         $tabs[] = new tabobject('view', $viewurl, get_string('cohorts', 'cohort'));
 659     }
 660     if (has_capability('moodle/cohort:manage', $context)) {
 661         $addurl = new moodle_url('/cohort/edit.php', array('contextid' => $context->id));
 662         $tabs[] = new tabobject('addcohort', $addurl, get_string('addcohort', 'cohort'));
 663         if ($currenturl->get_path() === $addurl->get_path() && !$currenturl->param('id')) {
 664             $currenttab = 'addcohort';
 665         }
 666
 667         $uploadurl = new moodle_url('/cohort/upload.php', array('contextid' => $context->id));
 668         $tabs[] = new tabobject('uploadcohorts', $uploadurl, get_string('uploadcohorts', 'cohort'));
 669         if ($currenturl->get_path() === $uploadurl->get_path()) {
 670             $currenttab = 'uploadcohorts';
 671         }
 672     }
 673     if (count($tabs) > 1) {
 674         return new tabtree($tabs, $currenttab);
 675     }
 676     return null;
 677 }
 678
 679 /**
 680  * Implements callback inplace_editable() allowing to edit values in-place
 681  *
 682  * @param string $itemtype
 683  * @param int $itemid
 684  * @param mixed $newvalue
 685  * @return \core\output\inplace_editable
 686  */
 687 function core_cohort_inplace_editable($itemtype, $itemid, $newvalue) {
 688     if ($itemtype === 'cohortname') {
 689         return \core_cohort\output\cohortname::update($itemid, $newvalue);
 690     } else if ($itemtype === 'cohortidnumber') {
 691         return \core_cohort\output\cohortidnumber::update($itemid, $newvalue);
 692     }
 693 }
 694
 695 /**
 696  * Returns a list of valid themes which can be displayed in a selector.
 697  *
 698  * @return array as (string)themename => (string)get_string_theme
 699  */
 700 function cohort_get_list_of_themes() {
 701     $themes = array();
 702     $allthemes = get_list_of_themes();
 703     foreach ($allthemes as $key => $theme) {
 704         if (empty($theme->hidefromselector)) {
 705             $themes[$key] = get_string('pluginname', 'theme_'.$theme->name);
 706         }
 707     }
 708     return $themes;
 709 }
 710
 711 /**
 712  * Returns custom fields data for provided cohorts.
 713  *
 714  * @param array $cohortids a list of cohort IDs to provide data for.
 715  * @return \core_customfield\data_controller[]
 716  */
 717 function cohort_get_custom_fields_data(array $cohortids): array {
 718     $result = [];
 719
 720     if (!empty($cohortids)) {
 721         $handler = core_cohort\customfield\cohort_handler::create();
 722         $result = $handler->get_instances_data($cohortids, true);
 723     }
 724
 725     return $result;
 726 }