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     $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 }