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