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 $DB;
  42
  43     if (!isset($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         $cohort->component = '';
  60     }
  61     if (!isset($cohort->timecreated)) {
  62         $cohort->timecreated = time();
  63     }
  64     if (!isset($cohort->timemodified)) {
  65         $cohort->timemodified = $cohort->timecreated;
  66     }
  67
  68     $cohort->id = $DB->insert_record('cohort', $cohort);
  69
  70     $event = \core\event\cohort_created::create(array(
  71         'context' => context::instance_by_id($cohort->contextid),
  72         'objectid' => $cohort->id,
  73     ));
  74     $event->add_record_snapshot('cohort', $cohort);
  75     $event->trigger();
  76
  77     return $cohort->id;
  78 }
  79
  80 /**
  81  * Update existing cohort.
  82  * @param  stdClass $cohort
  83  * @return void
  84  */
  85 function cohort_update_cohort($cohort) {
  86     global $DB;
  87     if (property_exists($cohort, 'component') and empty($cohort->component)) {
  88         // prevent NULLs
  89         $cohort->component = '';
  90     }
  91     $cohort->timemodified = time();
  92     $DB->update_record('cohort', $cohort);
  93
  94     $event = \core\event\cohort_updated::create(array(
  95         'context' => context::instance_by_id($cohort->contextid),
  96         'objectid' => $cohort->id,
  97     ));
  98     $event->trigger();
  99 }
 100
 101 /**
 102  * Delete cohort.
 103  * @param  stdClass $cohort
 104  * @return void
 105  */
 106 function cohort_delete_cohort($cohort) {
 107     global $DB;
 108
 109     if ($cohort->component) {
 110         // TODO: add component delete callback
 111     }
 112
 113     $DB->delete_records('cohort_members', array('cohortid'=>$cohort->id));
 114     $DB->delete_records('cohort', array('id'=>$cohort->id));
 115
 116     // Notify the competency subsystem.
 117     \core_competency\api::hook_cohort_deleted($cohort);
 118
 119     $event = \core\event\cohort_deleted::create(array(
 120         'context' => context::instance_by_id($cohort->contextid),
 121         'objectid' => $cohort->id,
 122     ));
 123     $event->add_record_snapshot('cohort', $cohort);
 124     $event->trigger();
 125 }
 126
 127 /**
 128  * Somehow deal with cohorts when deleting course category,
 129  * we can not just delete them because they might be used in enrol
 130  * plugins or referenced in external systems.
 131  * @param  stdClass|coursecat $category
 132  * @return void
 133  */
 134 function cohort_delete_category($category) {
 135     global $DB;
 136     // TODO: make sure that cohorts are really, really not used anywhere and delete, for now just move to parent or system context
 137
 138     $oldcontext = context_coursecat::instance($category->id);
 139
 140     if ($category->parent and $parent = $DB->get_record('course_categories', array('id'=>$category->parent))) {
 141         $parentcontext = context_coursecat::instance($parent->id);
 142         $sql = "UPDATE {cohort} SET contextid = :newcontext WHERE contextid = :oldcontext";
 143         $params = array('oldcontext'=>$oldcontext->id, 'newcontext'=>$parentcontext->id);
 144     } else {
 145         $syscontext = context_system::instance();
 146         $sql = "UPDATE {cohort} SET contextid = :newcontext WHERE contextid = :oldcontext";
 147         $params = array('oldcontext'=>$oldcontext->id, 'newcontext'=>$syscontext->id);
 148     }
 149
 150     $DB->execute($sql, $params);
 151 }
 152
 153 /**
 154  * Add cohort member
 155  * @param  int $cohortid
 156  * @param  int $userid
 157  * @return void
 158  */
 159 function cohort_add_member($cohortid, $userid) {
 160     global $DB;
 161     if ($DB->record_exists('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid))) {
 162         // No duplicates!
 163         return;
 164     }
 165     $record = new stdClass();
 166     $record->cohortid  = $cohortid;
 167     $record->userid    = $userid;
 168     $record->timeadded = time();
 169     $DB->insert_record('cohort_members', $record);
 170
 171     $cohort = $DB->get_record('cohort', array('id' => $cohortid), '*', MUST_EXIST);
 172
 173     $event = \core\event\cohort_member_added::create(array(
 174         'context' => context::instance_by_id($cohort->contextid),
 175         'objectid' => $cohortid,
 176         'relateduserid' => $userid,
 177     ));
 178     $event->add_record_snapshot('cohort', $cohort);
 179     $event->trigger();
 180 }
 181
 182 /**
 183  * Remove cohort member
 184  * @param  int $cohortid
 185  * @param  int $userid
 186  * @return void
 187  */
 188 function cohort_remove_member($cohortid, $userid) {
 189     global $DB;
 190     $DB->delete_records('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid));
 191
 192     $cohort = $DB->get_record('cohort', array('id' => $cohortid), '*', MUST_EXIST);
 193
 194     $event = \core\event\cohort_member_removed::create(array(
 195         'context' => context::instance_by_id($cohort->contextid),
 196         'objectid' => $cohortid,
 197         'relateduserid' => $userid,
 198     ));
 199     $event->add_record_snapshot('cohort', $cohort);
 200     $event->trigger();
 201 }
 202
 203 /**
 204  * Is this user a cohort member?
 205  * @param int $cohortid
 206  * @param int $userid
 207  * @return bool
 208  */
 209 function cohort_is_member($cohortid, $userid) {
 210     global $DB;
 211
 212     return $DB->record_exists('cohort_members', array('cohortid'=>$cohortid, 'userid'=>$userid));
 213 }
 214
 215 /**
 216  * Returns the list of cohorts visible to the current user in the given course.
 217  *
 218  * The following fields are returned in each record: id, name, contextid, idnumber, visible
 219  * Fields memberscnt and enrolledcnt will be also returned if requested
 220  *
 221  * @param context $currentcontext
 222  * @param int $withmembers one of the COHORT_XXX constants that allows to return non empty cohorts only
 223  *      or cohorts with enroled/not enroled users, or just return members count
 224  * @param int $offset
 225  * @param int $limit
 226  * @param string $search
 227  * @return array
 228  */
 229 function cohort_get_available_cohorts($currentcontext, $withmembers = 0, $offset = 0, $limit = 25, $search = '') {
 230     global $DB;
 231
 232     $params = array();
 233
 234     // Build context subquery. Find the list of parent context where user is able to see any or visible-only cohorts.
 235     // Since this method is normally called for the current course all parent contexts are already preloaded.
 236     $contextsany = array_filter($currentcontext->get_parent_context_ids(),
 237         create_function('$a', 'return has_capability("moodle/cohort:view", context::instance_by_id($a));'));
 238     $contextsvisible = array_diff($currentcontext->get_parent_context_ids(), $contextsany);
 239     if (empty($contextsany) && empty($contextsvisible)) {
 240         // User does not have any permissions to view cohorts.
 241         return array();
 242     }
 243     $subqueries = array();
 244     if (!empty($contextsany)) {
 245         list($parentsql, $params1) = $DB->get_in_or_equal($contextsany, SQL_PARAMS_NAMED, 'ctxa');
 246         $subqueries[] = 'c.contextid ' . $parentsql;
 247         $params = array_merge($params, $params1);
 248     }
 249     if (!empty($contextsvisible)) {
 250         list($parentsql, $params1) = $DB->get_in_or_equal($contextsvisible, SQL_PARAMS_NAMED, 'ctxv');
 251         $subqueries[] = '(c.visible = 1 AND c.contextid ' . $parentsql. ')';
 252         $params = array_merge($params, $params1);
 253     }
 254     $wheresql = '(' . implode(' OR ', $subqueries) . ')';
 255
 256     // Build the rest of the query.
 257     $fromsql = "";
 258     $fieldssql = 'c.id, c.name, c.contextid, c.idnumber, c.visible';
 259     $groupbysql = '';
 260     $havingsql = '';
 261     if ($withmembers) {
 262         $fieldssql .= ', s.memberscnt';
 263         $subfields = "c.id, COUNT(DISTINCT cm.userid) AS memberscnt";
 264         $groupbysql = " GROUP BY c.id";
 265         $fromsql = " LEFT JOIN {cohort_members} cm ON cm.cohortid = c.id ";
 266         if (in_array($withmembers,
 267                 array(COHORT_COUNT_ENROLLED_MEMBERS, COHORT_WITH_ENROLLED_MEMBERS_ONLY, COHORT_WITH_NOTENROLLED_MEMBERS_ONLY))) {
 268             list($esql, $params2) = get_enrolled_sql($currentcontext);
 269             $fromsql .= " LEFT JOIN ($esql) u ON u.id = cm.userid ";
 270             $params = array_merge($params2, $params);
 271             $fieldssql .= ', s.enrolledcnt';
 272             $subfields .= ', COUNT(DISTINCT u.id) AS enrolledcnt';
 273         }
 274         if ($withmembers == COHORT_WITH_MEMBERS_ONLY) {
 275             $havingsql = " HAVING COUNT(DISTINCT cm.userid) > 0";
 276         } else if ($withmembers == COHORT_WITH_ENROLLED_MEMBERS_ONLY) {
 277             $havingsql = " HAVING COUNT(DISTINCT u.id) > 0";
 278         } else if ($withmembers == COHORT_WITH_NOTENROLLED_MEMBERS_ONLY) {
 279             $havingsql = " HAVING COUNT(DISTINCT cm.userid) > COUNT(DISTINCT u.id)";
 280         }
 281     }
 282     if ($search) {
 283         list($searchsql, $searchparams) = cohort_get_search_query($search);
 284         $wheresql .= ' AND ' . $searchsql;
 285         $params = array_merge($params, $searchparams);
 286     }
 287
 288     if ($withmembers) {
 289         $sql = "SELECT " . str_replace('c.', 'cohort.', $fieldssql) . "
 290                   FROM {cohort} cohort
 291                   JOIN (SELECT $subfields
 292                           FROM {cohort} c $fromsql
 293                          WHERE $wheresql $groupbysql $havingsql
 294                         ) s ON cohort.id = s.id
 295               ORDER BY cohort.name, cohort.idnumber";
 296     } else {
 297         $sql = "SELECT $fieldssql
 298                   FROM {cohort} c $fromsql
 299                  WHERE $wheresql
 300               ORDER BY c.name, c.idnumber";
 301     }
 302
 303     return $DB->get_records_sql($sql, $params, $offset, $limit);
 304 }
 305
 306 /**
 307  * Check if cohort exists and user is allowed to access it from the given context.
 308  *
 309  * @param stdClass|int $cohortorid cohort object or id
 310  * @param context $currentcontext current context (course) where visibility is checked
 311  * @return boolean
 312  */
 313 function cohort_can_view_cohort($cohortorid, $currentcontext) {
 314     global $DB;
 315     if (is_numeric($cohortorid)) {
 316         $cohort = $DB->get_record('cohort', array('id' => $cohortorid), 'id, contextid, visible');
 317     } else {
 318         $cohort = $cohortorid;
 319     }
 320
 321     if ($cohort && in_array($cohort->contextid, $currentcontext->get_parent_context_ids())) {
 322         if ($cohort->visible) {
 323             return true;
 324         }
 325         $cohortcontext = context::instance_by_id($cohort->contextid);
 326         if (has_capability('moodle/cohort:view', $cohortcontext)) {
 327             return true;
 328         }
 329     }
 330     return false;
 331 }
 332
 333 /**
 334  * Get a cohort by id. Also does a visibility check and returns false if the user cannot see this cohort.
 335  *
 336  * @param stdClass|int $cohortorid cohort object or id
 337  * @param context $currentcontext current context (course) where visibility is checked
 338  * @return stdClass|boolean
 339  */
 340 function cohort_get_cohort($cohortorid, $currentcontext) {
 341     global $DB;
 342     if (is_numeric($cohortorid)) {
 343         $cohort = $DB->get_record('cohort', array('id' => $cohortorid), 'id, contextid, visible');
 344     } else {
 345         $cohort = $cohortorid;
 346     }
 347
 348     if ($cohort && in_array($cohort->contextid, $currentcontext->get_parent_context_ids())) {
 349         if ($cohort->visible) {
 350             return $cohort;
 351         }
 352         $cohortcontext = context::instance_by_id($cohort->contextid);
 353         if (has_capability('moodle/cohort:view', $cohortcontext)) {
 354             return $cohort;
 355         }
 356     }
 357     return false;
 358 }
 359
 360 /**
 361  * Produces a part of SQL query to filter cohorts by the search string
 362  *
 363  * Called from {@link cohort_get_cohorts()}, {@link cohort_get_all_cohorts()} and {@link cohort_get_available_cohorts()}
 364  *
 365  * @access private
 366  *
 367  * @param string $search search string
 368  * @param string $tablealias alias of cohort table in the SQL query (highly recommended if other tables are used in query)
 369  * @return array of two elements - SQL condition and array of named parameters
 370  */
 371 function cohort_get_search_query($search, $tablealias = '') {
 372     global $DB;
 373     $params = array();
 374     if (empty($search)) {
 375         // This function should not be called if there is no search string, just in case return dummy query.
 376         return array('1=1', $params);
 377     }
 378     if ($tablealias && substr($tablealias, -1) !== '.') {
 379         $tablealias .= '.';
 380     }
 381     $searchparam = '%' . $DB->sql_like_escape($search) . '%';
 382     $conditions = array();
 383     $fields = array('name', 'idnumber', 'description');
 384     $cnt = 0;
 385     foreach ($fields as $field) {
 386         $conditions[] = $DB->sql_like($tablealias . $field, ':csearch' . $cnt, false);
 387         $params['csearch' . $cnt] = $searchparam;
 388         $cnt++;
 389     }
 390     $sql = '(' . implode(' OR ', $conditions) . ')';
 391     return array($sql, $params);
 392 }
 393
 394 /**
 395  * Get all the cohorts defined in given context.
 396  *
 397  * The function does not check user capability to view/manage cohorts in the given context
 398  * assuming that it has been already verified.
 399  *
 400  * @param int $contextid
 401  * @param int $page number of the current page
 402  * @param int $perpage items per page
 403  * @param string $search search string
 404  * @return array    Array(totalcohorts => int, cohorts => array, allcohorts => int)
 405  */
 406 function cohort_get_cohorts($contextid, $page = 0, $perpage = 25, $search = '') {
 407     global $DB;
 408
 409     $fields = "SELECT *";
 410     $countfields = "SELECT COUNT(1)";
 411     $sql = " FROM {cohort}
 412              WHERE contextid = :contextid";
 413     $params = array('contextid' => $contextid);
 414     $order = " ORDER BY name ASC, idnumber ASC";
 415
 416     if (!empty($search)) {
 417         list($searchcondition, $searchparams) = cohort_get_search_query($search);
 418         $sql .= ' AND ' . $searchcondition;
 419         $params = array_merge($params, $searchparams);
 420     }
 421
 422     $totalcohorts = $allcohorts = $DB->count_records('cohort', array('contextid' => $contextid));
 423     if (!empty($search)) {
 424         $totalcohorts = $DB->count_records_sql($countfields . $sql, $params);
 425     }
 426     $cohorts = $DB->get_records_sql($fields . $sql . $order, $params, $page*$perpage, $perpage);
 427
 428     return array('totalcohorts' => $totalcohorts, 'cohorts' => $cohorts, 'allcohorts' => $allcohorts);
 429 }
 430
 431 /**
 432  * Get all the cohorts defined anywhere in system.
 433  *
 434  * The function assumes that user capability to view/manage cohorts on system level
 435  * has already been verified. This function only checks if such capabilities have been
 436  * revoked in child (categories) contexts.
 437  *
 438  * @param int $page number of the current page
 439  * @param int $perpage items per page
 440  * @param string $search search string
 441  * @return array    Array(totalcohorts => int, cohorts => array, allcohorts => int)
 442  */
 443 function cohort_get_all_cohorts($page = 0, $perpage = 25, $search = '') {
 444     global $DB;
 445
 446     $fields = "SELECT c.*, ".context_helper::get_preload_record_columns_sql('ctx');
 447     $countfields = "SELECT COUNT(*)";
 448     $sql = " FROM {cohort} c
 449              JOIN {context} ctx ON ctx.id = c.contextid ";
 450     $params = array();
 451     $wheresql = '';
 452
 453     if ($excludedcontexts = cohort_get_invisible_contexts()) {
 454         list($excludedsql, $excludedparams) = $DB->get_in_or_equal($excludedcontexts, SQL_PARAMS_NAMED, 'excl', false);
 455         $wheresql = ' WHERE c.contextid '.$excludedsql;
 456         $params = array_merge($params, $excludedparams);
 457     }
 458
 459     $totalcohorts = $allcohorts = $DB->count_records_sql($countfields . $sql . $wheresql, $params);
 460
 461     if (!empty($search)) {
 462         list($searchcondition, $searchparams) = cohort_get_search_query($search, 'c');
 463         $wheresql .= ($wheresql ? ' AND ' : ' WHERE ') . $searchcondition;
 464         $params = array_merge($params, $searchparams);
 465         $totalcohorts = $DB->count_records_sql($countfields . $sql . $wheresql, $params);
 466     }
 467
 468     $order = " ORDER BY c.name ASC, c.idnumber ASC";
 469     $cohorts = $DB->get_records_sql($fields . $sql . $wheresql . $order, $params, $page*$perpage, $perpage);
 470
 471     // Preload used contexts, they will be used to check view/manage/assign capabilities and display categories names.
 472     foreach (array_keys($cohorts) as $key) {
 473         context_helper::preload_from_record($cohorts[$key]);
 474     }
 475
 476     return array('totalcohorts' => $totalcohorts, 'cohorts' => $cohorts, 'allcohorts' => $allcohorts);
 477 }
 478
 479 /**
 480  * Returns list of contexts where cohorts are present but current user does not have capability to view/manage them.
 481  *
 482  * This function is called from {@link cohort_get_all_cohorts()} to ensure correct pagination in rare cases when user
 483  * is revoked capability in child contexts. It assumes that user's capability to view/manage cohorts on system
 484  * level has already been verified.
 485  *
 486  * @access private
 487  *
 488  * @return array array of context ids
 489  */
 490 function cohort_get_invisible_contexts() {
 491     global $DB;
 492     if (is_siteadmin()) {
 493         // Shortcut, admin can do anything and can not be prohibited from any context.
 494         return array();
 495     }
 496     $records = $DB->get_recordset_sql("SELECT DISTINCT ctx.id, ".context_helper::get_preload_record_columns_sql('ctx')." ".
 497         "FROM {context} ctx JOIN {cohort} c ON ctx.id = c.contextid ");
 498     $excludedcontexts = array();
 499     foreach ($records as $ctx) {
 500         context_helper::preload_from_record($ctx);
 501         if (!has_any_capability(array('moodle/cohort:manage', 'moodle/cohort:view'), context::instance_by_id($ctx->id))) {
 502             $excludedcontexts[] = $ctx->id;
 503         }
 504     }
 505     return $excludedcontexts;
 506 }
 507
 508 /**
 509  * Returns navigation controls (tabtree) to be displayed on cohort management pages
 510  *
 511  * @param context $context system or category context where cohorts controls are about to be displayed
 512  * @param moodle_url $currenturl
 513  * @return null|renderable
 514  */
 515 function cohort_edit_controls(context $context, moodle_url $currenturl) {
 516     $tabs = array();
 517     $currenttab = 'view';
 518     $viewurl = new moodle_url('/cohort/index.php', array('contextid' => $context->id));
 519     if (($searchquery = $currenturl->get_param('search'))) {
 520         $viewurl->param('search', $searchquery);
 521     }
 522     if ($context->contextlevel == CONTEXT_SYSTEM) {
 523         $tabs[] = new tabobject('view', new moodle_url($viewurl, array('showall' => 0)), get_string('systemcohorts', 'cohort'));
 524         $tabs[] = new tabobject('viewall', new moodle_url($viewurl, array('showall' => 1)), get_string('allcohorts', 'cohort'));
 525         if ($currenturl->get_param('showall')) {
 526             $currenttab = 'viewall';
 527         }
 528     } else {
 529         $tabs[] = new tabobject('view', $viewurl, get_string('cohorts', 'cohort'));
 530     }
 531     if (has_capability('moodle/cohort:manage', $context)) {
 532         $addurl = new moodle_url('/cohort/edit.php', array('contextid' => $context->id));
 533         $tabs[] = new tabobject('addcohort', $addurl, get_string('addcohort', 'cohort'));
 534         if ($currenturl->get_path() === $addurl->get_path() && !$currenturl->param('id')) {
 535             $currenttab = 'addcohort';
 536         }
 537
 538         $uploadurl = new moodle_url('/cohort/upload.php', array('contextid' => $context->id));
 539         $tabs[] = new tabobject('uploadcohorts', $uploadurl, get_string('uploadcohorts', 'cohort'));
 540         if ($currenturl->get_path() === $uploadurl->get_path()) {
 541             $currenttab = 'uploadcohorts';
 542         }
 543     }
 544     if (count($tabs) > 1) {
 545         return new tabtree($tabs, $currenttab);
 546     }
 547     return null;
 548 }
 549
 550 /**
 551  * Implements callback inplace_editable() allowing to edit values in-place
 552  *
 553  * @param string $itemtype
 554  * @param int $itemid
 555  * @param mixed $newvalue
 556  * @return \core\output\inplace_editable
 557  */
 558 function core_cohort_inplace_editable($itemtype, $itemid, $newvalue) {
 559     if ($itemtype === 'cohortname') {
 560         return \core_cohort\output\cohortname::update($itemid, $newvalue);
 561     } else if ($itemtype === 'cohortidnumber') {
 562         return \core_cohort\output\cohortidnumber::update($itemid, $newvalue);
 563     }
 564 }