lib/completionlib.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  * Contains classes, functions and constants used during the tracking
  19  * of activity completion for users.
  20  *
  21  * Completion top-level options (admin setting enablecompletion)
  22  *
  23  * @package core_completion
  24  * @category completion
  25  * @copyright 1999 onwards Martin Dougiamas   {@link http://moodle.com}
  26  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29 defined('MOODLE_INTERNAL') || die();
  30
  31 /**
  32  * Include the required completion libraries
  33  */
  34 require_once $CFG->libdir.'/completion/completion_aggregation.php';
  35 require_once $CFG->libdir.'/completion/completion_criteria.php';
  36 require_once $CFG->libdir.'/completion/completion_completion.php';
  37 require_once $CFG->libdir.'/completion/completion_criteria_completion.php';
  38
  39
  40 /**
  41  * The completion system is enabled in this site/course
  42  */
  43 define('COMPLETION_ENABLED', 1);
  44 /**
  45  * The completion system is not enabled in this site/course
  46  */
  47 define('COMPLETION_DISABLED', 0);
  48
  49 /**
  50  * Completion tracking is disabled for this activity
  51  * This is a completion tracking option per-activity  (course_modules/completion)
  52  */
  53 define('COMPLETION_TRACKING_NONE', 0);
  54
  55 /**
  56  * Manual completion tracking (user ticks box) is enabled for this activity
  57  * This is a completion tracking option per-activity  (course_modules/completion)
  58  */
  59 define('COMPLETION_TRACKING_MANUAL', 1);
  60 /**
  61  * Automatic completion tracking (system ticks box) is enabled for this activity
  62  * This is a completion tracking option per-activity  (course_modules/completion)
  63  */
  64 define('COMPLETION_TRACKING_AUTOMATIC', 2);
  65
  66 /**
  67  * The user has not completed this activity.
  68  * This is a completion state value (course_modules_completion/completionstate)
  69  */
  70 define('COMPLETION_INCOMPLETE', 0);
  71 /**
  72  * The user has completed this activity. It is not specified whether they have
  73  * passed or failed it.
  74  * This is a completion state value (course_modules_completion/completionstate)
  75  */
  76 define('COMPLETION_COMPLETE', 1);
  77 /**
  78  * The user has completed this activity with a grade above the pass mark.
  79  * This is a completion state value (course_modules_completion/completionstate)
  80  */
  81 define('COMPLETION_COMPLETE_PASS', 2);
  82 /**
  83  * The user has completed this activity but their grade is less than the pass mark
  84  * This is a completion state value (course_modules_completion/completionstate)
  85  */
  86 define('COMPLETION_COMPLETE_FAIL', 3);
  87
  88 /**
  89  * The effect of this change to completion status is unknown.
  90  * A completion effect changes (used only in update_state)
  91  */
  92 define('COMPLETION_UNKNOWN', -1);
  93 /**
  94  * The user's grade has changed, so their new state might be
  95  * COMPLETION_COMPLETE_PASS or COMPLETION_COMPLETE_FAIL.
  96  * A completion effect changes (used only in update_state)
  97  */
  98 define('COMPLETION_GRADECHANGE', -2);
  99
 100 /**
 101  * User must view this activity.
 102  * Whether view is required to create an activity (course_modules/completionview)
 103  */
 104 define('COMPLETION_VIEW_REQUIRED', 1);
 105 /**
 106  * User does not need to view this activity
 107  * Whether view is required to create an activity (course_modules/completionview)
 108  */
 109 define('COMPLETION_VIEW_NOT_REQUIRED', 0);
 110
 111 /**
 112  * User has viewed this activity.
 113  * Completion viewed state (course_modules_completion/viewed)
 114  */
 115 define('COMPLETION_VIEWED', 1);
 116 /**
 117  * User has not viewed this activity.
 118  * Completion viewed state (course_modules_completion/viewed)
 119  */
 120 define('COMPLETION_NOT_VIEWED', 0);
 121
 122 /**
 123  * Cache expiry time in seconds (10 minutes)
 124  * Completion cacheing
 125  */
 126 define('COMPLETION_CACHE_EXPIRY', 10*60);
 127
 128 /**
 129  * Completion details should be ORed together and you should return false if
 130  * none apply.
 131  */
 132 define('COMPLETION_OR', false);
 133 /**
 134  * Completion details should be ANDed together and you should return true if
 135  * none apply
 136  */
 137 define('COMPLETION_AND', true);
 138
 139 /**
 140  * Course completion criteria aggregation method.
 141  */
 142 define('COMPLETION_AGGREGATION_ALL', 1);
 143 /**
 144  * Course completion criteria aggregation method.
 145  */
 146 define('COMPLETION_AGGREGATION_ANY', 2);
 147
 148
 149 /**
 150  * Class represents completion information for a course.
 151  *
 152  * Does not contain any data, so you can safely construct it multiple times
 153  * without causing any problems.
 154  *
 155  * @package core
 156  * @category completion
 157  * @copyright 2008 Sam Marshall
 158  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 159  */
 160 class completion_info {
 161
 162     /* @var stdClass Course object passed during construction */
 163     private $course;
 164
 165     /* @var int Course id */
 166     public $course_id;
 167
 168     /* @var array Completion criteria {@link completion_info::get_criteria()}  */
 169     private $criteria;
 170
 171     /**
 172      * Return array of aggregation methods
 173      * @return array
 174      */
 175     public static function get_aggregation_methods() {
 176         return array(
 177             COMPLETION_AGGREGATION_ALL => get_string('all'),
 178             COMPLETION_AGGREGATION_ANY => get_string('any', 'completion'),
 179         );
 180     }
 181
 182     /**
 183      * Constructs with course details.
 184      *
 185      * When instantiating a new completion info object you must provide a course
 186      * object with at least id, and enablecompletion properties.
 187      *
 188      * @param stdClass $course Moodle course object.
 189      */
 190     public function __construct($course) {
 191         $this->course = $course;
 192         $this->course_id = $course->id;
 193     }
 194
 195     /**
 196      * Determines whether completion is enabled across entire site.
 197      *
 198      * @return bool COMPLETION_ENABLED (true) if completion is enabled for the site,
 199      *     COMPLETION_DISABLED (false) if it's complete
 200      */
 201     public static function is_enabled_for_site() {
 202         global $CFG;
 203         return !empty($CFG->enablecompletion);
 204     }
 205
 206     /**
 207      * Checks whether completion is enabled in a particular course and possibly
 208      * activity.
 209      *
 210      * @param stdClass|cm_info $cm Course-module object. If not specified, returns the course
 211      *   completion enable state.
 212      * @return mixed COMPLETION_ENABLED or COMPLETION_DISABLED (==0) in the case of
 213      *   site and course; COMPLETION_TRACKING_MANUAL, _AUTOMATIC or _NONE (==0)
 214      *   for a course-module.
 215      */
 216     public function is_enabled($cm = null) {
 217         global $CFG, $DB;
 218
 219         // First check global completion
 220         if (!isset($CFG->enablecompletion) || $CFG->enablecompletion == COMPLETION_DISABLED) {
 221             return COMPLETION_DISABLED;
 222         }
 223
 224         // Load data if we do not have enough
 225         if (!isset($this->course->enablecompletion)) {
 226             $this->course->enablecompletion = $DB->get_field('course', 'enablecompletion', array('id' => $this->course->id));
 227         }
 228
 229         // Check course completion
 230         if ($this->course->enablecompletion == COMPLETION_DISABLED) {
 231             return COMPLETION_DISABLED;
 232         }
 233
 234         // If there was no $cm and we got this far, then it's enabled
 235         if (!$cm) {
 236             return COMPLETION_ENABLED;
 237         }
 238
 239         // Return course-module completion value
 240         return $cm->completion;
 241     }
 242
 243     /**
 244      * Displays the 'Your progress' help icon, if completion tracking is enabled.
 245      * Just prints the result of display_help_icon().
 246      *
 247      * @deprecated since Moodle 2.0 - Use display_help_icon instead.
 248      */
 249     public function print_help_icon() {
 250         print $this->display_help_icon();
 251     }
 252
 253     /**
 254      * Returns the 'Your progress' help icon, if completion tracking is enabled.
 255      *
 256      * @return string HTML code for help icon, or blank if not needed
 257      */
 258     public function display_help_icon() {
 259         global $PAGE, $OUTPUT;
 260         $result = '';
 261         if ($this->is_enabled() && !$PAGE->user_is_editing() && isloggedin() && !isguestuser()) {
 262             $result .= '<span id = "completionprogressid" class="completionprogress">'.get_string('yourprogress','completion').' ';
 263             $result .= $OUTPUT->help_icon('completionicons', 'completion');
 264             $result .= '</span>';
 265         }
 266         return $result;
 267     }
 268
 269     /**
 270      * Get a course completion for a user
 271      *
 272      * @param int $user_id User id
 273      * @param int $criteriatype Specific criteria type to return
 274      * @return bool|completion_criteria_completion returns false on fail
 275      */
 276     public function get_completion($user_id, $criteriatype) {
 277         $completions = $this->get_completions($user_id, $criteriatype);
 278
 279         if (empty($completions)) {
 280             return false;
 281         } elseif (count($completions) > 1) {
 282             print_error('multipleselfcompletioncriteria', 'completion');
 283         }
 284
 285         return $completions[0];
 286     }
 287
 288     /**
 289      * Get all course criteria's completion objects for a user
 290      *
 291      * @param int $user_id User id
 292      * @param int $criteriatype Specific criteria type to return (optional)
 293      * @return array
 294      */
 295     public function get_completions($user_id, $criteriatype = null) {
 296         $criterion = $this->get_criteria($criteriatype);
 297
 298         $completions = array();
 299
 300         foreach ($criterion as $criteria) {
 301             $params = array(
 302                 'course'        => $this->course_id,
 303                 'userid'        => $user_id,
 304                 'criteriaid'    => $criteria->id
 305             );
 306
 307             $completion = new completion_criteria_completion($params);
 308             $completion->attach_criteria($criteria);
 309
 310             $completions[] = $completion;
 311         }
 312
 313         return $completions;
 314     }
 315
 316     /**
 317      * Get completion object for a user and a criteria
 318      *
 319      * @param int $user_id User id
 320      * @param completion_criteria $criteria Criteria object
 321      * @return completion_criteria_completion
 322      */
 323     public function get_user_completion($user_id, $criteria) {
 324         $params = array(
 325             'criteriaid'    => $criteria->id,
 326             'userid'        => $user_id
 327         );
 328
 329         $completion = new completion_criteria_completion($params);
 330         return $completion;
 331     }
 332
 333     /**
 334      * Check if course has completion criteria set
 335      *
 336      * @return bool Returns true if there are criteria
 337      */
 338     public function has_criteria() {
 339         $criteria = $this->get_criteria();
 340
 341         return (bool) count($criteria);
 342     }
 343
 344     /**
 345      * Get course completion criteria
 346      *
 347      * @param int $criteriatype Specific criteria type to return (optional)
 348      */
 349     public function get_criteria($criteriatype = null) {
 350
 351         // Fill cache if empty
 352         if (!is_array($this->criteria)) {
 353             global $DB;
 354
 355             $params = array(
 356                 'course'    => $this->course->id
 357             );
 358
 359             // Load criteria from database
 360             $records = (array)$DB->get_records('course_completion_criteria', $params);
 361
 362             // Build array of criteria objects
 363             $this->criteria = array();
 364             foreach ($records as $record) {
 365                 $this->criteria[$record->id] = completion_criteria::factory($record);
 366             }
 367         }
 368
 369         // If after all criteria
 370         if ($criteriatype === null) {
 371             return $this->criteria;
 372         }
 373
 374         // If we are only after a specific criteria type
 375         $criteria = array();
 376         foreach ($this->criteria as $criterion) {
 377
 378             if ($criterion->criteriatype != $criteriatype) {
 379                 continue;
 380             }
 381
 382             $criteria[$criterion->id] = $criterion;
 383         }
 384
 385         return $criteria;
 386     }
 387
 388     /**
 389      * Get aggregation method
 390      *
 391      * @param int $criteriatype If none supplied, get overall aggregation method (optional)
 392      * @return int One of COMPLETION_AGGREGATION_ALL or COMPLETION_AGGREGATION_ANY
 393      */
 394     public function get_aggregation_method($criteriatype = null) {
 395         $params = array(
 396             'course'        => $this->course_id,
 397             'criteriatype'  => $criteriatype
 398         );
 399
 400         $aggregation = new completion_aggregation($params);
 401
 402         if (!$aggregation->id) {
 403             $aggregation->method = COMPLETION_AGGREGATION_ALL;
 404         }
 405
 406         return $aggregation->method;
 407     }
 408
 409     /**
 410      * Get incomplete course completion criteria
 411      *
 412      * @return array
 413      */
 414     public function get_incomplete_criteria() {
 415         $incomplete = array();
 416
 417         foreach ($this->get_criteria() as $criteria) {
 418             if (!$criteria->is_complete()) {
 419                 $incomplete[] = $criteria;
 420             }
 421         }
 422
 423         return $incomplete;
 424     }
 425
 426     /**
 427      * Clear old course completion criteria
 428      */
 429     public function clear_criteria() {
 430         global $DB;
 431         $DB->delete_records('course_completion_criteria', array('course' => $this->course_id));
 432         $DB->delete_records('course_completion_aggr_methd', array('course' => $this->course_id));
 433
 434         $this->delete_course_completion_data();
 435     }
 436
 437     /**
 438      * Has the supplied user completed this course
 439      *
 440      * @param int $user_id User's id
 441      * @return boolean
 442      */
 443     public function is_course_complete($user_id) {
 444         $params = array(
 445             'userid'    => $user_id,
 446             'course'  => $this->course_id
 447         );
 448
 449         $ccompletion = new completion_completion($params);
 450         return $ccompletion->is_complete();
 451     }
 452
 453     /**
 454      * Updates (if necessary) the completion state of activity $cm for the given
 455      * user.
 456      *
 457      * For manual completion, this function is called when completion is toggled
 458      * with $possibleresult set to the target state.
 459      *
 460      * For automatic completion, this function should be called every time a module
 461      * does something which might influence a user's completion state. For example,
 462      * if a forum provides options for marking itself 'completed' once a user makes
 463      * N posts, this function should be called every time a user makes a new post.
 464      * [After the post has been saved to the database]. When calling, you do not
 465      * need to pass in the new completion state. Instead this function carries out
 466      * completion calculation by checking grades and viewed state itself, and
 467      * calling the involved module via modulename_get_completion_state() to check
 468      * module-specific conditions.
 469      *
 470      * @param stdClass|cm_info $cm Course-module
 471      * @param int $possibleresult Expected completion result. If the event that
 472      *   has just occurred (e.g. add post) can only result in making the activity
 473      *   complete when it wasn't before, use COMPLETION_COMPLETE. If the event that
 474      *   has just occurred (e.g. delete post) can only result in making the activity
 475      *   not complete when it was previously complete, use COMPLETION_INCOMPLETE.
 476      *   Otherwise use COMPLETION_UNKNOWN. Setting this value to something other than
 477      *   COMPLETION_UNKNOWN significantly improves performance because it will abandon
 478      *   processing early if the user's completion state already matches the expected
 479      *   result. For manual events, COMPLETION_COMPLETE or COMPLETION_INCOMPLETE
 480      *   must be used; these directly set the specified state.
 481      * @param int $userid User ID to be updated. Default 0 = current user
 482      * @return void
 483      */
 484     public function update_state($cm, $possibleresult=COMPLETION_UNKNOWN, $userid=0) {
 485         global $USER, $SESSION;
 486
 487         // Do nothing if completion is not enabled for that activity
 488         if (!$this->is_enabled($cm)) {
 489             return;
 490         }
 491
 492         // Get current value of completion state and do nothing if it's same as
 493         // the possible result of this change. If the change is to COMPLETE and the
 494         // current value is one of the COMPLETE_xx subtypes, ignore that as well
 495         $current = $this->get_data($cm, false, $userid);
 496         if ($possibleresult == $current->completionstate ||
 497             ($possibleresult == COMPLETION_COMPLETE &&
 498                 ($current->completionstate == COMPLETION_COMPLETE_PASS ||
 499                 $current->completionstate == COMPLETION_COMPLETE_FAIL))) {
 500             return;
 501         }
 502
 503         if ($cm->completion == COMPLETION_TRACKING_MANUAL) {
 504             // For manual tracking we set the result directly
 505             switch($possibleresult) {
 506                 case COMPLETION_COMPLETE:
 507                 case COMPLETION_INCOMPLETE:
 508                     $newstate = $possibleresult;
 509                     break;
 510                 default:
 511                     $this->internal_systemerror("Unexpected manual completion state for {$cm->id}: $possibleresult");
 512             }
 513
 514         } else {
 515             // Automatic tracking; get new state
 516             $newstate = $this->internal_get_state($cm, $userid, $current);
 517         }
 518
 519         // If changed, update
 520         if ($newstate != $current->completionstate) {
 521             $current->completionstate = $newstate;
 522             $current->timemodified    = time();
 523             $this->internal_set_data($cm, $current);
 524         }
 525     }
 526
 527     /**
 528      * Calculates the completion state for an activity and user.
 529      *
 530      * Internal function. Not private, so we can unit-test it.
 531      *
 532      * @param stdClass|cm_info $cm Activity
 533      * @param int $userid ID of user
 534      * @param stdClass $current Previous completion information from database
 535      * @return mixed
 536      */
 537     public function internal_get_state($cm, $userid, $current) {
 538         global $USER, $DB, $CFG;
 539
 540         // Get user ID
 541         if (!$userid) {
 542             $userid = $USER->id;
 543         }
 544
 545         // Check viewed
 546         if ($cm->completionview == COMPLETION_VIEW_REQUIRED &&
 547             $current->viewed == COMPLETION_NOT_VIEWED) {
 548
 549             return COMPLETION_INCOMPLETE;
 550         }
 551
 552         // Modname hopefully is provided in $cm but just in case it isn't, let's grab it
 553         if (!isset($cm->modname)) {
 554             $cm->modname = $DB->get_field('modules', 'name', array('id'=>$cm->module));
 555         }
 556
 557         $newstate = COMPLETION_COMPLETE;
 558
 559         // Check grade
 560         if (!is_null($cm->completiongradeitemnumber)) {
 561             require_once($CFG->libdir.'/gradelib.php');
 562             $item = grade_item::fetch(array('courseid'=>$cm->course, 'itemtype'=>'mod',
 563                 'itemmodule'=>$cm->modname, 'iteminstance'=>$cm->instance,
 564                 'itemnumber'=>$cm->completiongradeitemnumber));
 565             if ($item) {
 566                 // Fetch 'grades' (will be one or none)
 567                 $grades = grade_grade::fetch_users_grades($item, array($userid), false);
 568                 if (empty($grades)) {
 569                     // No grade for user
 570                     return COMPLETION_INCOMPLETE;
 571                 }
 572                 if (count($grades) > 1) {
 573                     $this->internal_systemerror("Unexpected result: multiple grades for
 574                         item '{$item->id}', user '{$userid}'");
 575                 }
 576                 $newstate = self::internal_get_grade_state($item, reset($grades));
 577                 if ($newstate == COMPLETION_INCOMPLETE) {
 578                     return COMPLETION_INCOMPLETE;
 579                 }
 580
 581             } else {
 582                 $this->internal_systemerror("Cannot find grade item for '{$cm->modname}'
 583                     cm '{$cm->id}' matching number '{$cm->completiongradeitemnumber}'");
 584             }
 585         }
 586
 587         if (plugin_supports('mod', $cm->modname, FEATURE_COMPLETION_HAS_RULES)) {
 588             $function = $cm->modname.'_get_completion_state';
 589             if (!function_exists($function)) {
 590                 $this->internal_systemerror("Module {$cm->modname} claims to support
 591                     FEATURE_COMPLETION_HAS_RULES but does not have required
 592                     {$cm->modname}_get_completion_state function");
 593             }
 594             if (!$function($this->course, $cm, $userid, COMPLETION_AND)) {
 595                 return COMPLETION_INCOMPLETE;
 596             }
 597         }
 598
 599         return $newstate;
 600
 601     }
 602
 603     /**
 604      * Marks a module as viewed.
 605      *
 606      * Should be called whenever a module is 'viewed' (it is up to the module how to
 607      * determine that). Has no effect if viewing is not set as a completion condition.
 608      *
 609      * Note that this function must be called before you print the page header because
 610      * it is possible that the navigation block may depend on it. If you call it after
 611      * printing the header, it shows a developer debug warning.
 612      *
 613      * @param stdClass|cm_info $cm Activity
 614      * @param int $userid User ID or 0 (default) for current user
 615      * @return void
 616      */
 617     public function set_module_viewed($cm, $userid=0) {
 618         global $PAGE, $UNITTEST;
 619         if ($PAGE->headerprinted && empty($UNITTEST->running)) {
 620             debugging('set_module_viewed must be called before header is printed',
 621                     DEBUG_DEVELOPER);
 622         }
 623         // Don't do anything if view condition is not turned on
 624         if ($cm->completionview == COMPLETION_VIEW_NOT_REQUIRED || !$this->is_enabled($cm)) {
 625             return;
 626         }
 627         // Get current completion state
 628         $data = $this->get_data($cm, $userid);
 629         // If we already viewed it, don't do anything
 630         if ($data->viewed == COMPLETION_VIEWED) {
 631             return;
 632         }
 633         // OK, change state, save it, and update completion
 634         $data->viewed = COMPLETION_VIEWED;
 635         $this->internal_set_data($cm, $data);
 636         $this->update_state($cm, COMPLETION_COMPLETE, $userid);
 637     }
 638
 639     /**
 640      * Determines how much completion data exists for an activity. This is used when
 641      * deciding whether completion information should be 'locked' in the module
 642      * editing form.
 643      *
 644      * @param cm_info $cm Activity
 645      * @return int The number of users who have completion data stored for this
 646      *   activity, 0 if none
 647      */
 648     public function count_user_data($cm) {
 649         global $DB;
 650
 651         return $DB->get_field_sql("
 652     SELECT
 653         COUNT(1)
 654     FROM
 655         {course_modules_completion}
 656     WHERE
 657         coursemoduleid=? AND completionstate<>0", array($cm->id));
 658     }
 659
 660     /**
 661      * Determines how much course completion data exists for a course. This is used when
 662      * deciding whether completion information should be 'locked' in the completion
 663      * settings form and activity completion settings.
 664      *
 665      * @param int $user_id Optionally only get course completion data for a single user
 666      * @return int The number of users who have completion data stored for this
 667      *     course, 0 if none
 668      */
 669     public function count_course_user_data($user_id = null) {
 670         global $DB;
 671
 672         $sql = '
 673     SELECT
 674         COUNT(1)
 675     FROM
 676         {course_completion_crit_compl}
 677     WHERE
 678         course = ?
 679         ';
 680
 681         $params = array($this->course_id);
 682
 683         // Limit data to a single user if an ID is supplied
 684         if ($user_id) {
 685             $sql .= ' AND userid = ?';
 686             $params[] = $user_id;
 687         }
 688
 689         return $DB->get_field_sql($sql, $params);
 690     }
 691
 692     /**
 693      * Check if this course's completion criteria should be locked
 694      *
 695      * @return boolean
 696      */
 697     public function is_course_locked() {
 698         return (bool) $this->count_course_user_data();
 699     }
 700
 701     /**
 702      * Deletes all course completion completion data.
 703      *
 704      * Intended to be used when unlocking completion criteria settings.
 705      */
 706     public function delete_course_completion_data() {
 707         global $DB;
 708
 709         $DB->delete_records('course_completions', array('course' => $this->course_id));
 710         $DB->delete_records('course_completion_crit_compl', array('course' => $this->course_id));
 711     }
 712
 713     /**
 714      * Deletes completion state related to an activity for all users.
 715      *
 716      * Intended for use only when the activity itself is deleted.
 717      *
 718      * @param stdClass|cm_info $cm Activity
 719      */
 720     public function delete_all_state($cm) {
 721         global $SESSION, $DB;
 722
 723         // Delete from database
 724         $DB->delete_records('course_modules_completion', array('coursemoduleid'=>$cm->id));
 725
 726         // Erase cache data for current user if applicable
 727         if (isset($SESSION->completioncache) &&
 728             array_key_exists($cm->course, $SESSION->completioncache) &&
 729             array_key_exists($cm->id, $SESSION->completioncache[$cm->course])) {
 730
 731             unset($SESSION->completioncache[$cm->course][$cm->id]);
 732         }
 733
 734         // Check if there is an associated course completion criteria
 735         $criteria = $this->get_criteria(COMPLETION_CRITERIA_TYPE_ACTIVITY);
 736         $acriteria = false;
 737         foreach ($criteria as $criterion) {
 738             if ($criterion->moduleinstance == $cm->id) {
 739                 $acriteria = $criterion;
 740                 break;
 741             }
 742         }
 743
 744         if ($acriteria) {
 745             // Delete all criteria completions relating to this activity
 746             $DB->delete_records('course_completion_crit_compl', array('course' => $this->course_id, 'criteriaid' => $acriteria->id));
 747             $DB->delete_records('course_completions', array('course' => $this->course_id));
 748         }
 749     }
 750
 751     /**
 752      * Recalculates completion state related to an activity for all users.
 753      *
 754      * Intended for use if completion conditions change. (This should be avoided
 755      * as it may cause some things to become incomplete when they were previously
 756      * complete, with the effect - for example - of hiding a later activity that
 757      * was previously available.)
 758      *
 759      * Resetting state of manual tickbox has same result as deleting state for
 760      * it.
 761      *
 762      * @param stcClass|cm_info $cm Activity
 763      */
 764     public function reset_all_state($cm) {
 765         global $DB;
 766
 767         if ($cm->completion == COMPLETION_TRACKING_MANUAL) {
 768             $this->delete_all_state($cm);
 769             return;
 770         }
 771         // Get current list of users with completion state
 772         $rs = $DB->get_recordset('course_modules_completion', array('coursemoduleid'=>$cm->id), '', 'userid');
 773         $keepusers = array();
 774         foreach ($rs as $rec) {
 775             $keepusers[] = $rec->userid;
 776         }
 777         $rs->close();
 778
 779         // Delete all existing state [also clears session cache for current user]
 780         $this->delete_all_state($cm);
 781
 782         // Merge this with list of planned users (according to roles)
 783         $trackedusers = $this->get_tracked_users();
 784         foreach ($trackedusers as $trackeduser) {
 785             $keepusers[] = $trackeduser->id;
 786         }
 787         $keepusers = array_unique($keepusers);
 788
 789         // Recalculate state for each kept user
 790         foreach ($keepusers as $keepuser) {
 791             $this->update_state($cm, COMPLETION_UNKNOWN, $keepuser);
 792         }
 793     }
 794
 795     /**
 796      * Obtains completion data for a particular activity and user (from the
 797      * session cache if available, or by SQL query)
 798      *
 799      * @param stcClass|cm_info $cm Activity; only required field is ->id
 800      * @param bool $wholecourse If true (default false) then, when necessary to
 801      *   fill the cache, retrieves information from the entire course not just for
 802      *   this one activity
 803      * @param int $userid User ID or 0 (default) for current user
 804      * @param array $modinfo Supply the value here - this is used for unit
 805      *   testing and so that it can be called recursively from within
 806      *   get_fast_modinfo. (Needs only list of all CMs with IDs.)
 807      *   Otherwise the method calls get_fast_modinfo itself.
 808      * @return object Completion data (record from course_modules_completion)
 809      */
 810     public function get_data($cm, $wholecourse = false, $userid = 0, $modinfo = null) {
 811         global $USER, $CFG, $SESSION, $DB;
 812
 813         // Get user ID
 814         if (!$userid) {
 815             $userid = $USER->id;
 816         }
 817
 818         // Is this the current user?
 819         $currentuser = $userid==$USER->id;
 820
 821         if ($currentuser && is_object($SESSION)) {
 822             // Make sure cache is present and is for current user (loginas
 823             // changes this)
 824             if (!isset($SESSION->completioncache) || $SESSION->completioncacheuserid!=$USER->id) {
 825                 $SESSION->completioncache = array();
 826                 $SESSION->completioncacheuserid = $USER->id;
 827             }
 828             // Expire any old data from cache
 829             foreach ($SESSION->completioncache as $courseid=>$activities) {
 830                 if (empty($activities['updated']) || $activities['updated'] < time()-COMPLETION_CACHE_EXPIRY) {
 831                     unset($SESSION->completioncache[$courseid]);
 832                 }
 833             }
 834             // See if requested data is present, if so use cache to get it
 835             if (isset($SESSION->completioncache) &&
 836                 array_key_exists($this->course->id, $SESSION->completioncache) &&
 837                 array_key_exists($cm->id, $SESSION->completioncache[$this->course->id])) {
 838                 return $SESSION->completioncache[$this->course->id][$cm->id];
 839             }
 840         }
 841
 842         // Not there, get via SQL
 843         if ($currentuser && $wholecourse) {
 844             // Get whole course data for cache
 845             $alldatabycmc = $DB->get_records_sql("
 846     SELECT
 847         cmc.*
 848     FROM
 849         {course_modules} cm
 850         INNER JOIN {course_modules_completion} cmc ON cmc.coursemoduleid=cm.id
 851     WHERE
 852         cm.course=? AND cmc.userid=?", array($this->course->id, $userid));
 853
 854             // Reindex by cm id
 855             $alldata = array();
 856             if ($alldatabycmc) {
 857                 foreach ($alldatabycmc as $data) {
 858                     $alldata[$data->coursemoduleid] = $data;
 859                 }
 860             }
 861
 862             // Get the module info and build up condition info for each one
 863             if (empty($modinfo)) {
 864                 $modinfo = get_fast_modinfo($this->course, $userid);
 865             }
 866             foreach ($modinfo->cms as $othercm) {
 867                 if (array_key_exists($othercm->id, $alldata)) {
 868                     $data = $alldata[$othercm->id];
 869                 } else {
 870                     // Row not present counts as 'not complete'
 871                     $data = new StdClass;
 872                     $data->id              = 0;
 873                     $data->coursemoduleid  = $othercm->id;
 874                     $data->userid          = $userid;
 875                     $data->completionstate = 0;
 876                     $data->viewed          = 0;
 877                     $data->timemodified    = 0;
 878                 }
 879                 $SESSION->completioncache[$this->course->id][$othercm->id] = $data;
 880             }
 881             $SESSION->completioncache[$this->course->id]['updated'] = time();
 882
 883             if (!isset($SESSION->completioncache[$this->course->id][$cm->id])) {
 884                 $this->internal_systemerror("Unexpected error: course-module {$cm->id} could not be found on course {$this->course->id}");
 885             }
 886             return $SESSION->completioncache[$this->course->id][$cm->id];
 887
 888         } else {
 889             // Get single record
 890             $data = $DB->get_record('course_modules_completion', array('coursemoduleid'=>$cm->id, 'userid'=>$userid));
 891             if ($data == false) {
 892                 // Row not present counts as 'not complete'
 893                 $data = new StdClass;
 894                 $data->id              = 0;
 895                 $data->coursemoduleid  = $cm->id;
 896                 $data->userid          = $userid;
 897                 $data->completionstate = 0;
 898                 $data->viewed          = 0;
 899                 $data->timemodified    = 0;
 900             }
 901
 902             // Put in cache
 903             if ($currentuser) {
 904                 $SESSION->completioncache[$this->course->id][$cm->id] = $data;
 905                 // For single updates, only set date if it was empty before
 906                 if (empty($SESSION->completioncache[$this->course->id]['updated'])) {
 907                     $SESSION->completioncache[$this->course->id]['updated'] = time();
 908                 }
 909             }
 910         }
 911
 912         return $data;
 913     }
 914
 915     /**
 916      * Updates completion data for a particular coursemodule and user (user is
 917      * determined from $data).
 918      *
 919      * (Internal function. Not private, so we can unit-test it.)
 920      *
 921      * @param stdClass|cm_info $cm Activity
 922      * @param stdClass $data Data about completion for that user
 923      */
 924     public function internal_set_data($cm, $data) {
 925         global $USER, $SESSION, $DB;
 926
 927         $transaction = $DB->start_delegated_transaction();
 928         if (!$data->id) {
 929             // Check there isn't really a row
 930             $data->id = $DB->get_field('course_modules_completion', 'id',
 931                     array('coursemoduleid'=>$data->coursemoduleid, 'userid'=>$data->userid));
 932         }
 933         if (!$data->id) {
 934             // Didn't exist before, needs creating
 935             $data->id = $DB->insert_record('course_modules_completion', $data);
 936         } else {
 937             // Has real (nonzero) id meaning that a database row exists, update
 938             $DB->update_record('course_modules_completion', $data);
 939         }
 940         $transaction->allow_commit();
 941
 942         if ($data->userid == $USER->id) {
 943             $SESSION->completioncache[$cm->course][$cm->id] = $data;
 944             $reset = 'reset';
 945             get_fast_modinfo($reset);
 946         }
 947     }
 948
 949     /**
 950      * Obtains a list of activities for which completion is enabled on the
 951      * course. The list is ordered by the section order of those activities.
 952      *
 953      * @param array $modinfo For unit testing only, supply the value
 954      *   here. Otherwise the method calls get_fast_modinfo
 955      * @return array Array from $cmid => $cm of all activities with completion enabled,
 956      *   empty array if none
 957      */
 958     public function get_activities($modinfo=null) {
 959         global $DB;
 960
 961         // Obtain those activities which have completion turned on
 962         $withcompletion = $DB->get_records_select('course_modules', 'course='.$this->course->id.
 963           ' AND completion<>'.COMPLETION_TRACKING_NONE);
 964         if (!$withcompletion) {
 965             return array();
 966         }
 967
 968         // Use modinfo to get section order and also add in names
 969         if (empty($modinfo)) {
 970             $modinfo = get_fast_modinfo($this->course);
 971         }
 972         $result = array();
 973         foreach ($modinfo->sections as $sectioncms) {
 974             foreach ($sectioncms as $cmid) {
 975                 if (array_key_exists($cmid, $withcompletion)) {
 976                     $result[$cmid] = $withcompletion[$cmid];
 977                     $result[$cmid]->modname = $modinfo->cms[$cmid]->modname;
 978                     $result[$cmid]->name    = $modinfo->cms[$cmid]->name;
 979                 }
 980             }
 981         }
 982
 983         return $result;
 984     }
 985
 986     /**
 987      * Checks to see if the userid supplied has a tracked role in
 988      * this course
 989      *
 990      * @param int $userid User id
 991      * @return bool
 992      */
 993     public function is_tracked_user($userid) {
 994         global $DB;
 995
 996         $tracked = $this->generate_tracked_user_sql();
 997
 998         $sql  = "SELECT u.id ";
 999         $sql .= $tracked->sql;
1000         $sql .= ' AND u.id = :userid';
1001
1002         $params = $tracked->data;
1003         $params['userid'] = (int)$userid;
1004         return $DB->record_exists_sql($sql, $params);
1005     }
1006
1007     /**
1008      * Return number of users whose progress is tracked in this course
1009      *
1010      * Optionally supply a search's where clause, or a group id
1011      *
1012      * @param string $where Where clause sql
1013      * @param array $where_params Where clause params
1014      * @param int $groupid Group id
1015      * @return int
1016      */
1017     public function get_num_tracked_users($where = '', $where_params = array(), $groupid = 0) {
1018         global $DB;
1019
1020         $tracked = $this->generate_tracked_user_sql($groupid);
1021
1022         $sql  = "SELECT COUNT(u.id) ";
1023         $sql .= $tracked->sql;
1024
1025         if ($where) {
1026             $sql .= " AND $where";
1027         }
1028
1029         $params = array_merge($tracked->data, $where_params);
1030         return $DB->count_records_sql($sql, $params);
1031     }
1032
1033     /**
1034      * Return array of users whose progress is tracked in this course
1035      *
1036      * Optionally supply a search's where caluse, group id, sorting, paging
1037      *
1038      * @param string $where Where clause sql (optional)
1039      * @param array $where_params Where clause params (optional)
1040      * @param integer $groupid Group ID to restrict to (optional)
1041      * @param string $sort Order by clause (optional)
1042      * @param integer $limitfrom Result start (optional)
1043      * @param integer $limitnum Result max size (optional)
1044      * @param context $extracontext If set, includes extra user information fields
1045      *   as appropriate to display for current user in this context
1046      * @return array
1047      */
1048     public function get_tracked_users($where = '', $where_params = array(), $groupid = 0,
1049              $sort = '', $limitfrom = '', $limitnum = '', context $extracontext = null) {
1050
1051         global $DB;
1052
1053         $tracked = $this->generate_tracked_user_sql($groupid);
1054         $params = $tracked->data;
1055
1056         $sql = "
1057             SELECT
1058                 u.id,
1059                 u.firstname,
1060                 u.lastname,
1061                 u.idnumber
1062         ";
1063         if ($extracontext) {
1064             $sql .= get_extra_user_fields_sql($extracontext, 'u', '', array('idnumber'));
1065         }
1066
1067         $sql .= $tracked->sql;
1068
1069         if ($where) {
1070             $sql .= " AND $where";
1071             $params = array_merge($params, $where_params);
1072         }
1073
1074         if ($sort) {
1075             $sql .= " ORDER BY $sort";
1076         }
1077
1078         $users = $DB->get_records_sql($sql, $params, $limitfrom, $limitnum);
1079         return $users ? $users : array(); // In case it returns false
1080     }
1081
1082     /**
1083      * Generate the SQL for finding tracked users in this course
1084      *
1085      * Returns an object containing the sql fragment and an array of
1086      * bound data params.
1087      *
1088      * @param integer $groupid
1089      * @return stdClass With two properties, sql (string), and data (array)
1090      */
1091     public function generate_tracked_user_sql($groupid = 0) {
1092         global $CFG;
1093
1094         $return = new stdClass();
1095         $return->sql = '';
1096         $return->data = array();
1097
1098         if (!empty($CFG->gradebookroles)) {
1099             $roles = ' AND ra.roleid IN ('.$CFG->gradebookroles.')';
1100         } else {
1101             // This causes it to default to everyone (if there is no student role)
1102             $roles = '';
1103         }
1104
1105         // Build context sql
1106         $context = get_context_instance(CONTEXT_COURSE, $this->course->id);
1107         $parentcontexts = substr($context->path, 1); // kill leading slash
1108         $parentcontexts = str_replace('/', ',', $parentcontexts);
1109         if ($parentcontexts !== '') {
1110             $parentcontexts = ' OR ra.contextid IN ('.$parentcontexts.' )';
1111         }
1112
1113         $groupjoin   = '';
1114         $groupselect = '';
1115         if ($groupid) {
1116             $groupjoin   = "JOIN {groups_members} gm
1117                               ON gm.userid = u.id";
1118             $groupselect = " AND gm.groupid = :groupid ";
1119
1120             $return->data['groupid'] = $groupid;
1121         }
1122
1123         $return->sql = "
1124             FROM
1125                 {user} u
1126             INNER JOIN
1127                 {role_assignments} ra
1128              ON ra.userid = u.id
1129             INNER JOIN
1130                 {role} r
1131              ON r.id = ra.roleid
1132             INNER JOIN
1133                 {user_enrolments} ue
1134              ON ue.userid = u.id
1135             INNER JOIN
1136                 {enrol} e
1137              ON e.id = ue.enrolid
1138             INNER JOIN
1139                 {course} c
1140              ON c.id = e.courseid
1141             $groupjoin
1142             WHERE
1143                 (ra.contextid = :contextid $parentcontexts)
1144             AND c.id = :courseid
1145             AND ue.status = 0
1146             AND e.status = 0
1147             AND ue.timestart < :now1
1148             AND (ue.timeend > :now2 OR ue.timeend = 0)
1149                 $groupselect
1150                 $roles
1151         ";
1152
1153         $now = time();
1154         $return->data['now1'] = $now;
1155         $return->data['now2'] = $now;
1156         $return->data['contextid'] = $context->id;
1157         $return->data['courseid'] = $this->course->id;
1158
1159         return $return;
1160     }
1161
1162     /**
1163      * Obtains progress information across a course for all users on that course, or
1164      * for all users in a specific group. Intended for use when displaying progress.
1165      *
1166      * This includes only users who, in course context, have one of the roles for
1167      * which progress is tracked (the gradebookroles admin option) and are enrolled in course.
1168      *
1169      * Users are included (in the first array) even if they do not have
1170      * completion progress for any course-module.
1171      *
1172      * @param bool $sortfirstname If true, sort by first name, otherwise sort by
1173      *   last name
1174      * @param string $where Where clause sql (optional)
1175      * @param array $where_params Where clause params (optional)
1176      * @param int $groupid Group ID or 0 (default)/false for all groups
1177      * @param int $pagesize Number of users to actually return (optional)
1178      * @param int $start User to start at if paging (optional)
1179      * @param context $extracontext If set, includes extra user information fields
1180      *   as appropriate to display for current user in this context
1181      * @return stdClass with ->total and ->start (same as $start) and ->users;
1182      *   an array of user objects (like mdl_user id, firstname, lastname)
1183      *   containing an additional ->progress array of coursemoduleid => completionstate
1184      */
1185     public function get_progress_all($where = '', $where_params = array(), $groupid = 0,
1186             $sort = '', $pagesize = '', $start = '', context $extracontext = null) {
1187         global $CFG, $DB;
1188
1189         // Get list of applicable users
1190         $users = $this->get_tracked_users($where, $where_params, $groupid, $sort,
1191                 $start, $pagesize, $extracontext);
1192
1193         // Get progress information for these users in groups of 1, 000 (if needed)
1194         // to avoid making the SQL IN too long
1195         $results = array();
1196         $userids = array();
1197         foreach ($users as $user) {
1198             $userids[] = $user->id;
1199             $results[$user->id] = $user;
1200             $results[$user->id]->progress = array();
1201         }
1202
1203         for($i=0; $i<count($userids); $i+=1000) {
1204             $blocksize = count($userids)-$i < 1000 ? count($userids)-$i : 1000;
1205
1206             list($insql, $params) = $DB->get_in_or_equal(array_slice($userids, $i, $blocksize));
1207             array_splice($params, 0, 0, array($this->course->id));
1208             $rs = $DB->get_recordset_sql("
1209                 SELECT
1210                     cmc.*
1211                 FROM
1212                     {course_modules} cm
1213                     INNER JOIN {course_modules_completion} cmc ON cm.id=cmc.coursemoduleid
1214                 WHERE
1215                     cm.course=? AND cmc.userid $insql", $params);
1216             foreach ($rs as $progress) {
1217                 $progress = (object)$progress;
1218                 $results[$progress->userid]->progress[$progress->coursemoduleid] = $progress;
1219             }
1220             $rs->close();
1221         }
1222
1223         return $results;
1224     }
1225
1226     /**
1227      * Called by grade code to inform the completion system when a grade has
1228      * been changed. If the changed grade is used to determine completion for
1229      * the course-module, then the completion status will be updated.
1230      *
1231      * @param stdClass|cm_info $cm Course-module for item that owns grade
1232      * @param grade_item $item Grade item
1233      * @param stdClass $grade
1234      * @param bool $deleted
1235      */
1236     public function inform_grade_changed($cm, $item, $grade, $deleted) {
1237         // Bail out now if completion is not enabled for course-module, it is enabled
1238         // but is set to manual, grade is not used to compute completion, or this
1239         // is a different numbered grade
1240         if (!$this->is_enabled($cm) ||
1241             $cm->completion == COMPLETION_TRACKING_MANUAL ||
1242             is_null($cm->completiongradeitemnumber) ||
1243             $item->itemnumber != $cm->completiongradeitemnumber) {
1244             return;
1245         }
1246
1247         // What is the expected result based on this grade?
1248         if ($deleted) {
1249             // Grade being deleted, so only change could be to make it incomplete
1250             $possibleresult = COMPLETION_INCOMPLETE;
1251         } else {
1252             $possibleresult = self::internal_get_grade_state($item, $grade);
1253         }
1254
1255         // OK, let's update state based on this
1256         $this->update_state($cm, $possibleresult, $grade->userid);
1257     }
1258
1259     /**
1260      * Calculates the completion state that would result from a graded item
1261      * (where grade-based completion is turned on) based on the actual grade
1262      * and settings.
1263      *
1264      * Internal function. Not private, so we can unit-test it.
1265      *
1266      * @param grade_item $item an instance of grade_item
1267      * @param grade_grade $grade an instance of grade_grade
1268      * @return int Completion state e.g. COMPLETION_INCOMPLETE
1269      */
1270     public static function internal_get_grade_state($item, $grade) {
1271         if (!$grade) {
1272             return COMPLETION_INCOMPLETE;
1273         }
1274         // Conditions to show pass/fail:
1275         // a) Grade has pass mark (default is 0.00000 which is boolean true so be careful)
1276         // b) Grade is visible (neither hidden nor hidden-until)
1277         if ($item->gradepass && $item->gradepass > 0.000009 && !$item->hidden) {
1278             // Use final grade if set otherwise raw grade
1279             $score = !is_null($grade->finalgrade) ? $grade->finalgrade : $grade->rawgrade;
1280
1281             // We are displaying and tracking pass/fail
1282             if ($score >= $item->gradepass) {
1283                 return COMPLETION_COMPLETE_PASS;
1284             } else {
1285                 return COMPLETION_COMPLETE_FAIL;
1286             }
1287         } else {
1288             // Not displaying pass/fail, so just if there is a grade
1289             if (!is_null($grade->finalgrade) || !is_null($grade->rawgrade)) {
1290                 // Grade exists, so maybe complete now
1291                 return COMPLETION_COMPLETE;
1292             } else {
1293                 // Grade does not exist, so maybe incomplete now
1294                 return COMPLETION_INCOMPLETE;
1295             }
1296         }
1297     }
1298
1299     /**
1300      * Aggregate activity completion state
1301      *
1302      * @param   int     $type   Aggregation type (COMPLETION_* constant)
1303      * @param   bool    $old    Old state
1304      * @param   bool    $new    New state
1305      * @return  bool
1306      */
1307     public static function aggregate_completion_states($type, $old, $new) {
1308         if ($type == COMPLETION_AND) {
1309             return $old && $new;
1310         } else {
1311             return $old || $new;
1312         }
1313     }
1314
1315     /**
1316      * This is to be used only for system errors (things that shouldn't happen)
1317      * and not user-level errors.
1318      *
1319      * @global type $CFG
1320      * @param string $error Error string (will not be displayed to user unless debugging is enabled)
1321      * @throws moodle_exception Exception with the error string as debug info
1322      */
1323     public function internal_systemerror($error) {
1324         global $CFG;
1325         throw new moodle_exception('err_system','completion',
1326             $CFG->wwwroot.'/course/view.php?id='.$this->course->id,null,$error);
1327     }
1328
1329     /**
1330      * For testing only. Wipes information cached in user session.
1331      */
1332     public static function wipe_session_cache() {
1333         global $SESSION;
1334         unset($SESSION->completioncache);
1335         unset($SESSION->completioncacheuserid);
1336     }
1337 }