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Differences Between: [Versions 39 and 310] [Versions 39 and 311] [Versions 39 and 400] [Versions 39 and 401] [Versions 39 and 402] [Versions 39 and 403]

   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   * Library of functions used by the quiz module.
  19   *
  20   * This contains functions that are called from within the quiz module only
  21   * Functions that are also called by core Moodle are in {@link lib.php}
  22   * This script also loads the code in {@link questionlib.php} which holds
  23   * the module-indpendent code for handling questions and which in turn
  24   * initialises all the questiontype classes.
  25   *
  26   * @package    mod_quiz
  27   * @copyright  1999 onwards Martin Dougiamas and others {@link http://moodle.com}
  28   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  29   */
  30  
  31  
  32  defined('MOODLE_INTERNAL') || die();
  33  
  34  require_once($CFG->dirroot . '/mod/quiz/lib.php');
  35  require_once($CFG->dirroot . '/mod/quiz/accessmanager.php');
  36  require_once($CFG->dirroot . '/mod/quiz/accessmanager_form.php');
  37  require_once($CFG->dirroot . '/mod/quiz/renderer.php');
  38  require_once($CFG->dirroot . '/mod/quiz/attemptlib.php');
  39  require_once($CFG->libdir . '/completionlib.php');
  40  require_once($CFG->libdir . '/filelib.php');
  41  require_once($CFG->libdir . '/questionlib.php');
  42  
  43  
  44  /**
  45   * @var int We show the countdown timer if there is less than this amount of time left before the
  46   * the quiz close date. (1 hour)
  47   */
  48  define('QUIZ_SHOW_TIME_BEFORE_DEADLINE', '3600');
  49  
  50  /**
  51   * @var int If there are fewer than this many seconds left when the student submits
  52   * a page of the quiz, then do not take them to the next page of the quiz. Instead
  53   * close the quiz immediately.
  54   */
  55  define('QUIZ_MIN_TIME_TO_CONTINUE', '2');
  56  
  57  /**
  58   * @var int We show no image when user selects No image from dropdown menu in quiz settings.
  59   */
  60  define('QUIZ_SHOWIMAGE_NONE', 0);
  61  
  62  /**
  63   * @var int We show small image when user selects small image from dropdown menu in quiz settings.
  64   */
  65  define('QUIZ_SHOWIMAGE_SMALL', 1);
  66  
  67  /**
  68   * @var int We show Large image when user selects Large image from dropdown menu in quiz settings.
  69   */
  70  define('QUIZ_SHOWIMAGE_LARGE', 2);
  71  
  72  
  73  // Functions related to attempts ///////////////////////////////////////////////
  74  
  75  /**
  76   * Creates an object to represent a new attempt at a quiz
  77   *
  78   * Creates an attempt object to represent an attempt at the quiz by the current
  79   * user starting at the current time. The ->id field is not set. The object is
  80   * NOT written to the database.
  81   *
  82   * @param object $quizobj the quiz object to create an attempt for.
  83   * @param int $attemptnumber the sequence number for the attempt.
  84   * @param object $lastattempt the previous attempt by this user, if any. Only needed
  85   *         if $attemptnumber > 1 and $quiz->attemptonlast is true.
  86   * @param int $timenow the time the attempt was started at.
  87   * @param bool $ispreview whether this new attempt is a preview.
  88   * @param int $userid  the id of the user attempting this quiz.
  89   *
  90   * @return object the newly created attempt object.
  91   */
  92  function quiz_create_attempt(quiz $quizobj, $attemptnumber, $lastattempt, $timenow, $ispreview = false, $userid = null) {
  93      global $USER;
  94  
  95      if ($userid === null) {
  96          $userid = $USER->id;
  97      }
  98  
  99      $quiz = $quizobj->get_quiz();
 100      if ($quiz->sumgrades < 0.000005 && $quiz->grade > 0.000005) {
 101          throw new moodle_exception('cannotstartgradesmismatch', 'quiz',
 102                  new moodle_url('/mod/quiz/view.php', array('q' => $quiz->id)),
 103                      array('grade' => quiz_format_grade($quiz, $quiz->grade)));
 104      }
 105  
 106      if ($attemptnumber == 1 || !$quiz->attemptonlast) {
 107          // We are not building on last attempt so create a new attempt.
 108          $attempt = new stdClass();
 109          $attempt->quiz = $quiz->id;
 110          $attempt->userid = $userid;
 111          $attempt->preview = 0;
 112          $attempt->layout = '';
 113      } else {
 114          // Build on last attempt.
 115          if (empty($lastattempt)) {
 116              print_error('cannotfindprevattempt', 'quiz');
 117          }
 118          $attempt = $lastattempt;
 119      }
 120  
 121      $attempt->attempt = $attemptnumber;
 122      $attempt->timestart = $timenow;
 123      $attempt->timefinish = 0;
 124      $attempt->timemodified = $timenow;
 125      $attempt->timemodifiedoffline = 0;
 126      $attempt->state = quiz_attempt::IN_PROGRESS;
 127      $attempt->currentpage = 0;
 128      $attempt->sumgrades = null;
 129  
 130      // If this is a preview, mark it as such.
 131      if ($ispreview) {
 132          $attempt->preview = 1;
 133      }
 134  
 135      $timeclose = $quizobj->get_access_manager($timenow)->get_end_time($attempt);
 136      if ($timeclose === false || $ispreview) {
 137          $attempt->timecheckstate = null;
 138      } else {
 139          $attempt->timecheckstate = $timeclose;
 140      }
 141  
 142      return $attempt;
 143  }
 144  /**
 145   * Start a normal, new, quiz attempt.
 146   *
 147   * @param quiz      $quizobj            the quiz object to start an attempt for.
 148   * @param question_usage_by_activity $quba
 149   * @param object    $attempt
 150   * @param integer   $attemptnumber      starting from 1
 151   * @param integer   $timenow            the attempt start time
 152   * @param array     $questionids        slot number => question id. Used for random questions, to force the choice
 153   *                                        of a particular actual question. Intended for testing purposes only.
 154   * @param array     $forcedvariantsbyslot slot number => variant. Used for questions with variants,
 155   *                                          to force the choice of a particular variant. Intended for testing
 156   *                                          purposes only.
 157   * @throws moodle_exception
 158   * @return object   modified attempt object
 159   */
 160  function quiz_start_new_attempt($quizobj, $quba, $attempt, $attemptnumber, $timenow,
 161                                  $questionids = array(), $forcedvariantsbyslot = array()) {
 162  
 163      // Usages for this user's previous quiz attempts.
 164      $qubaids = new \mod_quiz\question\qubaids_for_users_attempts(
 165              $quizobj->get_quizid(), $attempt->userid);
 166  
 167      // Fully load all the questions in this quiz.
 168      $quizobj->preload_questions();
 169      $quizobj->load_questions();
 170  
 171      // First load all the non-random questions.
 172      $randomfound = false;
 173      $slot = 0;
 174      $questions = array();
 175      $maxmark = array();
 176      $page = array();
 177      foreach ($quizobj->get_questions() as $questiondata) {
 178          $slot += 1;
 179          $maxmark[$slot] = $questiondata->maxmark;
 180          $page[$slot] = $questiondata->page;
 181          if ($questiondata->qtype == 'random') {
 182              $randomfound = true;
 183              continue;
 184          }
 185          if (!$quizobj->get_quiz()->shuffleanswers) {
 186              $questiondata->options->shuffleanswers = false;
 187          }
 188          $questions[$slot] = question_bank::make_question($questiondata);
 189      }
 190  
 191      // Then find a question to go in place of each random question.
 192      if ($randomfound) {
 193          $slot = 0;
 194          $usedquestionids = array();
 195          foreach ($questions as $question) {
 196              if (isset($usedquestions[$question->id])) {
 197                  $usedquestionids[$question->id] += 1;
 198              } else {
 199                  $usedquestionids[$question->id] = 1;
 200              }
 201          }
 202          $randomloader = new \core_question\bank\random_question_loader($qubaids, $usedquestionids);
 203  
 204          foreach ($quizobj->get_questions() as $questiondata) {
 205              $slot += 1;
 206              if ($questiondata->qtype != 'random') {
 207                  continue;
 208              }
 209  
 210              $tagids = quiz_retrieve_slot_tag_ids($questiondata->slotid);
 211  
 212              // Deal with fixed random choices for testing.
 213              if (isset($questionids[$quba->next_slot_number()])) {
 214                  if ($randomloader->is_question_available($questiondata->category,
 215                          (bool) $questiondata->questiontext, $questionids[$quba->next_slot_number()], $tagids)) {
 216                      $questions[$slot] = question_bank::load_question(
 217                              $questionids[$quba->next_slot_number()], $quizobj->get_quiz()->shuffleanswers);
 218                      continue;
 219                  } else {
 220                      throw new coding_exception('Forced question id not available.');
 221                  }
 222              }
 223  
 224              // Normal case, pick one at random.
 225              $questionid = $randomloader->get_next_question_id($questiondata->randomfromcategory,
 226                      $questiondata->randomincludingsubcategories, $tagids);
 227              if ($questionid === null) {
 228                  throw new moodle_exception('notenoughrandomquestions', 'quiz',
 229                                             $quizobj->view_url(), $questiondata);
 230              }
 231  
 232              $questions[$slot] = question_bank::load_question($questionid,
 233                      $quizobj->get_quiz()->shuffleanswers);
 234          }
 235      }
 236  
 237      // Finally add them all to the usage.
 238      ksort($questions);
 239      foreach ($questions as $slot => $question) {
 240          $newslot = $quba->add_question($question, $maxmark[$slot]);
 241          if ($newslot != $slot) {
 242              throw new coding_exception('Slot numbers have got confused.');
 243          }
 244      }
 245  
 246      // Start all the questions.
 247      $variantstrategy = new core_question\engine\variants\least_used_strategy($quba, $qubaids);
 248  
 249      if (!empty($forcedvariantsbyslot)) {
 250          $forcedvariantsbyseed = question_variant_forced_choices_selection_strategy::prepare_forced_choices_array(
 251              $forcedvariantsbyslot, $quba);
 252          $variantstrategy = new question_variant_forced_choices_selection_strategy(
 253              $forcedvariantsbyseed, $variantstrategy);
 254      }
 255  
 256      $quba->start_all_questions($variantstrategy, $timenow, $attempt->userid);
 257  
 258      // Work out the attempt layout.
 259      $sections = $quizobj->get_sections();
 260      foreach ($sections as $i => $section) {
 261          if (isset($sections[$i + 1])) {
 262              $sections[$i]->lastslot = $sections[$i + 1]->firstslot - 1;
 263          } else {
 264              $sections[$i]->lastslot = count($questions);
 265          }
 266      }
 267  
 268      $layout = array();
 269      foreach ($sections as $section) {
 270          if ($section->shufflequestions) {
 271              $questionsinthissection = array();
 272              for ($slot = $section->firstslot; $slot <= $section->lastslot; $slot += 1) {
 273                  $questionsinthissection[] = $slot;
 274              }
 275              shuffle($questionsinthissection);
 276              $questionsonthispage = 0;
 277              foreach ($questionsinthissection as $slot) {
 278                  if ($questionsonthispage && $questionsonthispage == $quizobj->get_quiz()->questionsperpage) {
 279                      $layout[] = 0;
 280                      $questionsonthispage = 0;
 281                  }
 282                  $layout[] = $slot;
 283                  $questionsonthispage += 1;
 284              }
 285  
 286          } else {
 287              $currentpage = $page[$section->firstslot];
 288              for ($slot = $section->firstslot; $slot <= $section->lastslot; $slot += 1) {
 289                  if ($currentpage !== null && $page[$slot] != $currentpage) {
 290                      $layout[] = 0;
 291                  }
 292                  $layout[] = $slot;
 293                  $currentpage = $page[$slot];
 294              }
 295          }
 296  
 297          // Each section ends with a page break.
 298          $layout[] = 0;
 299      }
 300      $attempt->layout = implode(',', $layout);
 301  
 302      return $attempt;
 303  }
 304  
 305  /**
 306   * Start a subsequent new attempt, in each attempt builds on last mode.
 307   *
 308   * @param question_usage_by_activity    $quba         this question usage
 309   * @param object                        $attempt      this attempt
 310   * @param object                        $lastattempt  last attempt
 311   * @return object                       modified attempt object
 312   *
 313   */
 314  function quiz_start_attempt_built_on_last($quba, $attempt, $lastattempt) {
 315      $oldquba = question_engine::load_questions_usage_by_activity($lastattempt->uniqueid);
 316  
 317      $oldnumberstonew = array();
 318      foreach ($oldquba->get_attempt_iterator() as $oldslot => $oldqa) {
 319          $newslot = $quba->add_question($oldqa->get_question(false), $oldqa->get_max_mark());
 320  
 321          $quba->start_question_based_on($newslot, $oldqa);
 322  
 323          $oldnumberstonew[$oldslot] = $newslot;
 324      }
 325  
 326      // Update attempt layout.
 327      $newlayout = array();
 328      foreach (explode(',', $lastattempt->layout) as $oldslot) {
 329          if ($oldslot != 0) {
 330              $newlayout[] = $oldnumberstonew[$oldslot];
 331          } else {
 332              $newlayout[] = 0;
 333          }
 334      }
 335      $attempt->layout = implode(',', $newlayout);
 336      return $attempt;
 337  }
 338  
 339  /**
 340   * The save started question usage and quiz attempt in db and log the started attempt.
 341   *
 342   * @param quiz                       $quizobj
 343   * @param question_usage_by_activity $quba
 344   * @param object                     $attempt
 345   * @return object                    attempt object with uniqueid and id set.
 346   */
 347  function quiz_attempt_save_started($quizobj, $quba, $attempt) {
 348      global $DB;
 349      // Save the attempt in the database.
 350      question_engine::save_questions_usage_by_activity($quba);
 351      $attempt->uniqueid = $quba->get_id();
 352      $attempt->id = $DB->insert_record('quiz_attempts', $attempt);
 353  
 354      // Params used by the events below.
 355      $params = array(
 356          'objectid' => $attempt->id,
 357          'relateduserid' => $attempt->userid,
 358          'courseid' => $quizobj->get_courseid(),
 359          'context' => $quizobj->get_context()
 360      );
 361      // Decide which event we are using.
 362      if ($attempt->preview) {
 363          $params['other'] = array(
 364              'quizid' => $quizobj->get_quizid()
 365          );
 366          $event = \mod_quiz\event\attempt_preview_started::create($params);
 367      } else {
 368          $event = \mod_quiz\event\attempt_started::create($params);
 369  
 370      }
 371  
 372      // Trigger the event.
 373      $event->add_record_snapshot('quiz', $quizobj->get_quiz());
 374      $event->add_record_snapshot('quiz_attempts', $attempt);
 375      $event->trigger();
 376  
 377      return $attempt;
 378  }
 379  
 380  /**
 381   * Returns an unfinished attempt (if there is one) for the given
 382   * user on the given quiz. This function does not return preview attempts.
 383   *
 384   * @param int $quizid the id of the quiz.
 385   * @param int $userid the id of the user.
 386   *
 387   * @return mixed the unfinished attempt if there is one, false if not.
 388   */
 389  function quiz_get_user_attempt_unfinished($quizid, $userid) {
 390      $attempts = quiz_get_user_attempts($quizid, $userid, 'unfinished', true);
 391      if ($attempts) {
 392          return array_shift($attempts);
 393      } else {
 394          return false;
 395      }
 396  }
 397  
 398  /**
 399   * Delete a quiz attempt.
 400   * @param mixed $attempt an integer attempt id or an attempt object
 401   *      (row of the quiz_attempts table).
 402   * @param object $quiz the quiz object.
 403   */
 404  function quiz_delete_attempt($attempt, $quiz) {
 405      global $DB;
 406      if (is_numeric($attempt)) {
 407          if (!$attempt = $DB->get_record('quiz_attempts', array('id' => $attempt))) {
 408              return;
 409          }
 410      }
 411  
 412      if ($attempt->quiz != $quiz->id) {
 413          debugging("Trying to delete attempt $attempt->id which belongs to quiz $attempt->quiz " .
 414                  "but was passed quiz $quiz->id.");
 415          return;
 416      }
 417  
 418      if (!isset($quiz->cmid)) {
 419          $cm = get_coursemodule_from_instance('quiz', $quiz->id, $quiz->course);
 420          $quiz->cmid = $cm->id;
 421      }
 422  
 423      question_engine::delete_questions_usage_by_activity($attempt->uniqueid);
 424      $DB->delete_records('quiz_attempts', array('id' => $attempt->id));
 425  
 426      // Log the deletion of the attempt if not a preview.
 427      if (!$attempt->preview) {
 428          $params = array(
 429              'objectid' => $attempt->id,
 430              'relateduserid' => $attempt->userid,
 431              'context' => context_module::instance($quiz->cmid),
 432              'other' => array(
 433                  'quizid' => $quiz->id
 434              )
 435          );
 436          $event = \mod_quiz\event\attempt_deleted::create($params);
 437          $event->add_record_snapshot('quiz_attempts', $attempt);
 438          $event->trigger();
 439      }
 440  
 441      // Search quiz_attempts for other instances by this user.
 442      // If none, then delete record for this quiz, this user from quiz_grades
 443      // else recalculate best grade.
 444      $userid = $attempt->userid;
 445      if (!$DB->record_exists('quiz_attempts', array('userid' => $userid, 'quiz' => $quiz->id))) {
 446          $DB->delete_records('quiz_grades', array('userid' => $userid, 'quiz' => $quiz->id));
 447      } else {
 448          quiz_save_best_grade($quiz, $userid);
 449      }
 450  
 451      quiz_update_grades($quiz, $userid);
 452  }
 453  
 454  /**
 455   * Delete all the preview attempts at a quiz, or possibly all the attempts belonging
 456   * to one user.
 457   * @param object $quiz the quiz object.
 458   * @param int $userid (optional) if given, only delete the previews belonging to this user.
 459   */
 460  function quiz_delete_previews($quiz, $userid = null) {
 461      global $DB;
 462      $conditions = array('quiz' => $quiz->id, 'preview' => 1);
 463      if (!empty($userid)) {
 464          $conditions['userid'] = $userid;
 465      }
 466      $previewattempts = $DB->get_records('quiz_attempts', $conditions);
 467      foreach ($previewattempts as $attempt) {
 468          quiz_delete_attempt($attempt, $quiz);
 469      }
 470  }
 471  
 472  /**
 473   * @param int $quizid The quiz id.
 474   * @return bool whether this quiz has any (non-preview) attempts.
 475   */
 476  function quiz_has_attempts($quizid) {
 477      global $DB;
 478      return $DB->record_exists('quiz_attempts', array('quiz' => $quizid, 'preview' => 0));
 479  }
 480  
 481  // Functions to do with quiz layout and pages //////////////////////////////////
 482  
 483  /**
 484   * Repaginate the questions in a quiz
 485   * @param int $quizid the id of the quiz to repaginate.
 486   * @param int $slotsperpage number of items to put on each page. 0 means unlimited.
 487   */
 488  function quiz_repaginate_questions($quizid, $slotsperpage) {
 489      global $DB;
 490      $trans = $DB->start_delegated_transaction();
 491  
 492      $sections = $DB->get_records('quiz_sections', array('quizid' => $quizid), 'firstslot ASC');
 493      $firstslots = array();
 494      foreach ($sections as $section) {
 495          if ((int)$section->firstslot === 1) {
 496              continue;
 497          }
 498          $firstslots[] = $section->firstslot;
 499      }
 500  
 501      $slots = $DB->get_records('quiz_slots', array('quizid' => $quizid),
 502              'slot');
 503      $currentpage = 1;
 504      $slotsonthispage = 0;
 505      foreach ($slots as $slot) {
 506          if (($firstslots && in_array($slot->slot, $firstslots)) ||
 507              ($slotsonthispage && $slotsonthispage == $slotsperpage)) {
 508              $currentpage += 1;
 509              $slotsonthispage = 0;
 510          }
 511          if ($slot->page != $currentpage) {
 512              $DB->set_field('quiz_slots', 'page', $currentpage, array('id' => $slot->id));
 513          }
 514          $slotsonthispage += 1;
 515      }
 516  
 517      $trans->allow_commit();
 518  }
 519  
 520  // Functions to do with quiz grades ////////////////////////////////////////////
 521  
 522  /**
 523   * Convert the raw grade stored in $attempt into a grade out of the maximum
 524   * grade for this quiz.
 525   *
 526   * @param float $rawgrade the unadjusted grade, fof example $attempt->sumgrades
 527   * @param object $quiz the quiz object. Only the fields grade, sumgrades and decimalpoints are used.
 528   * @param bool|string $format whether to format the results for display
 529   *      or 'question' to format a question grade (different number of decimal places.
 530   * @return float|string the rescaled grade, or null/the lang string 'notyetgraded'
 531   *      if the $grade is null.
 532   */
 533  function quiz_rescale_grade($rawgrade, $quiz, $format = true) {
 534      if (is_null($rawgrade)) {
 535          $grade = null;
 536      } else if ($quiz->sumgrades >= 0.000005) {
 537          $grade = $rawgrade * $quiz->grade / $quiz->sumgrades;
 538      } else {
 539          $grade = 0;
 540      }
 541      if ($format === 'question') {
 542          $grade = quiz_format_question_grade($quiz, $grade);
 543      } else if ($format) {
 544          $grade = quiz_format_grade($quiz, $grade);
 545      }
 546      return $grade;
 547  }
 548  
 549  /**
 550   * Get the feedback object for this grade on this quiz.
 551   *
 552   * @param float $grade a grade on this quiz.
 553   * @param object $quiz the quiz settings.
 554   * @return false|stdClass the record object or false if there is not feedback for the given grade
 555   * @since  Moodle 3.1
 556   */
 557  function quiz_feedback_record_for_grade($grade, $quiz) {
 558      global $DB;
 559  
 560      // With CBM etc, it is possible to get -ve grades, which would then not match
 561      // any feedback. Therefore, we replace -ve grades with 0.
 562      $grade = max($grade, 0);
 563  
 564      $feedback = $DB->get_record_select('quiz_feedback',
 565              'quizid = ? AND mingrade <= ? AND ? < maxgrade', array($quiz->id, $grade, $grade));
 566  
 567      return $feedback;
 568  }
 569  
 570  /**
 571   * Get the feedback text that should be show to a student who
 572   * got this grade on this quiz. The feedback is processed ready for diplay.
 573   *
 574   * @param float $grade a grade on this quiz.
 575   * @param object $quiz the quiz settings.
 576   * @param object $context the quiz context.
 577   * @return string the comment that corresponds to this grade (empty string if there is not one.
 578   */
 579  function quiz_feedback_for_grade($grade, $quiz, $context) {
 580  
 581      if (is_null($grade)) {
 582          return '';
 583      }
 584  
 585      $feedback = quiz_feedback_record_for_grade($grade, $quiz);
 586  
 587      if (empty($feedback->feedbacktext)) {
 588          return '';
 589      }
 590  
 591      // Clean the text, ready for display.
 592      $formatoptions = new stdClass();
 593      $formatoptions->noclean = true;
 594      $feedbacktext = file_rewrite_pluginfile_urls($feedback->feedbacktext, 'pluginfile.php',
 595              $context->id, 'mod_quiz', 'feedback', $feedback->id);
 596      $feedbacktext = format_text($feedbacktext, $feedback->feedbacktextformat, $formatoptions);
 597  
 598      return $feedbacktext;
 599  }
 600  
 601  /**
 602   * @param object $quiz the quiz database row.
 603   * @return bool Whether this quiz has any non-blank feedback text.
 604   */
 605  function quiz_has_feedback($quiz) {
 606      global $DB;
 607      static $cache = array();
 608      if (!array_key_exists($quiz->id, $cache)) {
 609          $cache[$quiz->id] = quiz_has_grades($quiz) &&
 610                  $DB->record_exists_select('quiz_feedback', "quizid = ? AND " .
 611                      $DB->sql_isnotempty('quiz_feedback', 'feedbacktext', false, true),
 612                  array($quiz->id));
 613      }
 614      return $cache[$quiz->id];
 615  }
 616  
 617  /**
 618   * Update the sumgrades field of the quiz. This needs to be called whenever
 619   * the grading structure of the quiz is changed. For example if a question is
 620   * added or removed, or a question weight is changed.
 621   *
 622   * You should call {@link quiz_delete_previews()} before you call this function.
 623   *
 624   * @param object $quiz a quiz.
 625   */
 626  function quiz_update_sumgrades($quiz) {
 627      global $DB;
 628  
 629      $sql = 'UPDATE {quiz}
 630              SET sumgrades = COALESCE((
 631                  SELECT SUM(maxmark)
 632                  FROM {quiz_slots}
 633                  WHERE quizid = {quiz}.id
 634              ), 0)
 635              WHERE id = ?';
 636      $DB->execute($sql, array($quiz->id));
 637      $quiz->sumgrades = $DB->get_field('quiz', 'sumgrades', array('id' => $quiz->id));
 638  
 639      if ($quiz->sumgrades < 0.000005 && quiz_has_attempts($quiz->id)) {
 640          // If the quiz has been attempted, and the sumgrades has been
 641          // set to 0, then we must also set the maximum possible grade to 0, or
 642          // we will get a divide by zero error.
 643          quiz_set_grade(0, $quiz);
 644      }
 645  }
 646  
 647  /**
 648   * Update the sumgrades field of the attempts at a quiz.
 649   *
 650   * @param object $quiz a quiz.
 651   */
 652  function quiz_update_all_attempt_sumgrades($quiz) {
 653      global $DB;
 654      $dm = new question_engine_data_mapper();
 655      $timenow = time();
 656  
 657      $sql = "UPDATE {quiz_attempts}
 658              SET
 659                  timemodified = :timenow,
 660                  sumgrades = (
 661                      {$dm->sum_usage_marks_subquery('uniqueid')}
 662                  )
 663              WHERE quiz = :quizid AND state = :finishedstate";
 664      $DB->execute($sql, array('timenow' => $timenow, 'quizid' => $quiz->id,
 665              'finishedstate' => quiz_attempt::FINISHED));
 666  }
 667  
 668  /**
 669   * The quiz grade is the maximum that student's results are marked out of. When it
 670   * changes, the corresponding data in quiz_grades and quiz_feedback needs to be
 671   * rescaled. After calling this function, you probably need to call
 672   * quiz_update_all_attempt_sumgrades, quiz_update_all_final_grades and
 673   * quiz_update_grades.
 674   *
 675   * @param float $newgrade the new maximum grade for the quiz.
 676   * @param object $quiz the quiz we are updating. Passed by reference so its
 677   *      grade field can be updated too.
 678   * @return bool indicating success or failure.
 679   */
 680  function quiz_set_grade($newgrade, $quiz) {
 681      global $DB;
 682      // This is potentially expensive, so only do it if necessary.
 683      if (abs($quiz->grade - $newgrade) < 1e-7) {
 684          // Nothing to do.
 685          return true;
 686      }
 687  
 688      $oldgrade = $quiz->grade;
 689      $quiz->grade = $newgrade;
 690  
 691      // Use a transaction, so that on those databases that support it, this is safer.
 692      $transaction = $DB->start_delegated_transaction();
 693  
 694      // Update the quiz table.
 695      $DB->set_field('quiz', 'grade', $newgrade, array('id' => $quiz->instance));
 696  
 697      if ($oldgrade < 1) {
 698          // If the old grade was zero, we cannot rescale, we have to recompute.
 699          // We also recompute if the old grade was too small to avoid underflow problems.
 700          quiz_update_all_final_grades($quiz);
 701  
 702      } else {
 703          // We can rescale the grades efficiently.
 704          $timemodified = time();
 705          $DB->execute("
 706                  UPDATE {quiz_grades}
 707                  SET grade = ? * grade, timemodified = ?
 708                  WHERE quiz = ?
 709          ", array($newgrade/$oldgrade, $timemodified, $quiz->id));
 710      }
 711  
 712      if ($oldgrade > 1e-7) {
 713          // Update the quiz_feedback table.
 714          $factor = $newgrade/$oldgrade;
 715          $DB->execute("
 716                  UPDATE {quiz_feedback}
 717                  SET mingrade = ? * mingrade, maxgrade = ? * maxgrade
 718                  WHERE quizid = ?
 719          ", array($factor, $factor, $quiz->id));
 720      }
 721  
 722      // Update grade item and send all grades to gradebook.
 723      quiz_grade_item_update($quiz);
 724      quiz_update_grades($quiz);
 725  
 726      $transaction->allow_commit();
 727      return true;
 728  }
 729  
 730  /**
 731   * Save the overall grade for a user at a quiz in the quiz_grades table
 732   *
 733   * @param object $quiz The quiz for which the best grade is to be calculated and then saved.
 734   * @param int $userid The userid to calculate the grade for. Defaults to the current user.
 735   * @param array $attempts The attempts of this user. Useful if you are
 736   * looping through many users. Attempts can be fetched in one master query to
 737   * avoid repeated querying.
 738   * @return bool Indicates success or failure.
 739   */
 740  function quiz_save_best_grade($quiz, $userid = null, $attempts = array()) {
 741      global $DB, $OUTPUT, $USER;
 742  
 743      if (empty($userid)) {
 744          $userid = $USER->id;
 745      }
 746  
 747      if (!$attempts) {
 748          // Get all the attempts made by the user.
 749          $attempts = quiz_get_user_attempts($quiz->id, $userid);
 750      }
 751  
 752      // Calculate the best grade.
 753      $bestgrade = quiz_calculate_best_grade($quiz, $attempts);
 754      $bestgrade = quiz_rescale_grade($bestgrade, $quiz, false);
 755  
 756      // Save the best grade in the database.
 757      if (is_null($bestgrade)) {
 758          $DB->delete_records('quiz_grades', array('quiz' => $quiz->id, 'userid' => $userid));
 759  
 760      } else if ($grade = $DB->get_record('quiz_grades',
 761              array('quiz' => $quiz->id, 'userid' => $userid))) {
 762          $grade->grade = $bestgrade;
 763          $grade->timemodified = time();
 764          $DB->update_record('quiz_grades', $grade);
 765  
 766      } else {
 767          $grade = new stdClass();
 768          $grade->quiz = $quiz->id;
 769          $grade->userid = $userid;
 770          $grade->grade = $bestgrade;
 771          $grade->timemodified = time();
 772          $DB->insert_record('quiz_grades', $grade);
 773      }
 774  
 775      quiz_update_grades($quiz, $userid);
 776  }
 777  
 778  /**
 779   * Calculate the overall grade for a quiz given a number of attempts by a particular user.
 780   *
 781   * @param object $quiz    the quiz settings object.
 782   * @param array $attempts an array of all the user's attempts at this quiz in order.
 783   * @return float          the overall grade
 784   */
 785  function quiz_calculate_best_grade($quiz, $attempts) {
 786  
 787      switch ($quiz->grademethod) {
 788  
 789          case QUIZ_ATTEMPTFIRST:
 790              $firstattempt = reset($attempts);
 791              return $firstattempt->sumgrades;
 792  
 793          case QUIZ_ATTEMPTLAST:
 794              $lastattempt = end($attempts);
 795              return $lastattempt->sumgrades;
 796  
 797          case QUIZ_GRADEAVERAGE:
 798              $sum = 0;
 799              $count = 0;
 800              foreach ($attempts as $attempt) {
 801                  if (!is_null($attempt->sumgrades)) {
 802                      $sum += $attempt->sumgrades;
 803                      $count++;
 804                  }
 805              }
 806              if ($count == 0) {
 807                  return null;
 808              }
 809              return $sum / $count;
 810  
 811          case QUIZ_GRADEHIGHEST:
 812          default:
 813              $max = null;
 814              foreach ($attempts as $attempt) {
 815                  if ($attempt->sumgrades > $max) {
 816                      $max = $attempt->sumgrades;
 817                  }
 818              }
 819              return $max;
 820      }
 821  }
 822  
 823  /**
 824   * Update the final grade at this quiz for all students.
 825   *
 826   * This function is equivalent to calling quiz_save_best_grade for all
 827   * users, but much more efficient.
 828   *
 829   * @param object $quiz the quiz settings.
 830   */
 831  function quiz_update_all_final_grades($quiz) {
 832      global $DB;
 833  
 834      if (!$quiz->sumgrades) {
 835          return;
 836      }
 837  
 838      $param = array('iquizid' => $quiz->id, 'istatefinished' => quiz_attempt::FINISHED);
 839      $firstlastattemptjoin = "JOIN (
 840              SELECT
 841                  iquiza.userid,
 842                  MIN(attempt) AS firstattempt,
 843                  MAX(attempt) AS lastattempt
 844  
 845              FROM {quiz_attempts} iquiza
 846  
 847              WHERE
 848                  iquiza.state = :istatefinished AND
 849                  iquiza.preview = 0 AND
 850                  iquiza.quiz = :iquizid
 851  
 852              GROUP BY iquiza.userid
 853          ) first_last_attempts ON first_last_attempts.userid = quiza.userid";
 854  
 855      switch ($quiz->grademethod) {
 856          case QUIZ_ATTEMPTFIRST:
 857              // Because of the where clause, there will only be one row, but we
 858              // must still use an aggregate function.
 859              $select = 'MAX(quiza.sumgrades)';
 860              $join = $firstlastattemptjoin;
 861              $where = 'quiza.attempt = first_last_attempts.firstattempt AND';
 862              break;
 863  
 864          case QUIZ_ATTEMPTLAST:
 865              // Because of the where clause, there will only be one row, but we
 866              // must still use an aggregate function.
 867              $select = 'MAX(quiza.sumgrades)';
 868              $join = $firstlastattemptjoin;
 869              $where = 'quiza.attempt = first_last_attempts.lastattempt AND';
 870              break;
 871  
 872          case QUIZ_GRADEAVERAGE:
 873              $select = 'AVG(quiza.sumgrades)';
 874              $join = '';
 875              $where = '';
 876              break;
 877  
 878          default:
 879          case QUIZ_GRADEHIGHEST:
 880              $select = 'MAX(quiza.sumgrades)';
 881              $join = '';
 882              $where = '';
 883              break;
 884      }
 885  
 886      if ($quiz->sumgrades >= 0.000005) {
 887          $finalgrade = $select . ' * ' . ($quiz->grade / $quiz->sumgrades);
 888      } else {
 889          $finalgrade = '0';
 890      }
 891      $param['quizid'] = $quiz->id;
 892      $param['quizid2'] = $quiz->id;
 893      $param['quizid3'] = $quiz->id;
 894      $param['quizid4'] = $quiz->id;
 895      $param['statefinished'] = quiz_attempt::FINISHED;
 896      $param['statefinished2'] = quiz_attempt::FINISHED;
 897      $finalgradesubquery = "
 898              SELECT quiza.userid, $finalgrade AS newgrade
 899              FROM {quiz_attempts} quiza
 900              $join
 901              WHERE
 902                  $where
 903                  quiza.state = :statefinished AND
 904                  quiza.preview = 0 AND
 905                  quiza.quiz = :quizid3
 906              GROUP BY quiza.userid";
 907  
 908      $changedgrades = $DB->get_records_sql("
 909              SELECT users.userid, qg.id, qg.grade, newgrades.newgrade
 910  
 911              FROM (
 912                  SELECT userid
 913                  FROM {quiz_grades} qg
 914                  WHERE quiz = :quizid
 915              UNION
 916                  SELECT DISTINCT userid
 917                  FROM {quiz_attempts} quiza2
 918                  WHERE
 919                      quiza2.state = :statefinished2 AND
 920                      quiza2.preview = 0 AND
 921                      quiza2.quiz = :quizid2
 922              ) users
 923  
 924              LEFT JOIN {quiz_grades} qg ON qg.userid = users.userid AND qg.quiz = :quizid4
 925  
 926              LEFT JOIN (
 927                  $finalgradesubquery
 928              ) newgrades ON newgrades.userid = users.userid
 929  
 930              WHERE
 931                  ABS(newgrades.newgrade - qg.grade) > 0.000005 OR
 932                  ((newgrades.newgrade IS NULL OR qg.grade IS NULL) AND NOT
 933                            (newgrades.newgrade IS NULL AND qg.grade IS NULL))",
 934                  // The mess on the previous line is detecting where the value is
 935                  // NULL in one column, and NOT NULL in the other, but SQL does
 936                  // not have an XOR operator, and MS SQL server can't cope with
 937                  // (newgrades.newgrade IS NULL) <> (qg.grade IS NULL).
 938              $param);
 939  
 940      $timenow = time();
 941      $todelete = array();
 942      foreach ($changedgrades as $changedgrade) {
 943  
 944          if (is_null($changedgrade->newgrade)) {
 945              $todelete[] = $changedgrade->userid;
 946  
 947          } else if (is_null($changedgrade->grade)) {
 948              $toinsert = new stdClass();
 949              $toinsert->quiz = $quiz->id;
 950              $toinsert->userid = $changedgrade->userid;
 951              $toinsert->timemodified = $timenow;
 952              $toinsert->grade = $changedgrade->newgrade;
 953              $DB->insert_record('quiz_grades', $toinsert);
 954  
 955          } else {
 956              $toupdate = new stdClass();
 957              $toupdate->id = $changedgrade->id;
 958              $toupdate->grade = $changedgrade->newgrade;
 959              $toupdate->timemodified = $timenow;
 960              $DB->update_record('quiz_grades', $toupdate);
 961          }
 962      }
 963  
 964      if (!empty($todelete)) {
 965          list($test, $params) = $DB->get_in_or_equal($todelete);
 966          $DB->delete_records_select('quiz_grades', 'quiz = ? AND userid ' . $test,
 967                  array_merge(array($quiz->id), $params));
 968      }
 969  }
 970  
 971  /**
 972   * Efficiently update check state time on all open attempts
 973   *
 974   * @param array $conditions optional restrictions on which attempts to update
 975   *                    Allowed conditions:
 976   *                      courseid => (array|int) attempts in given course(s)
 977   *                      userid   => (array|int) attempts for given user(s)
 978   *                      quizid   => (array|int) attempts in given quiz(s)
 979   *                      groupid  => (array|int) quizzes with some override for given group(s)
 980   *
 981   */
 982  function quiz_update_open_attempts(array $conditions) {
 983      global $DB;
 984  
 985      foreach ($conditions as &$value) {
 986          if (!is_array($value)) {
 987              $value = array($value);
 988          }
 989      }
 990  
 991      $params = array();
 992      $wheres = array("quiza.state IN ('inprogress', 'overdue')");
 993      $iwheres = array("iquiza.state IN ('inprogress', 'overdue')");
 994  
 995      if (isset($conditions['courseid'])) {
 996          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['courseid'], SQL_PARAMS_NAMED, 'cid');
 997          $params = array_merge($params, $inparams);
 998          $wheres[] = "quiza.quiz IN (SELECT q.id FROM {quiz} q WHERE q.course $incond)";
 999          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['courseid'], SQL_PARAMS_NAMED, 'icid');
1000          $params = array_merge($params, $inparams);
1001          $iwheres[] = "iquiza.quiz IN (SELECT q.id FROM {quiz} q WHERE q.course $incond)";
1002      }
1003  
1004      if (isset($conditions['userid'])) {
1005          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['userid'], SQL_PARAMS_NAMED, 'uid');
1006          $params = array_merge($params, $inparams);
1007          $wheres[] = "quiza.userid $incond";
1008          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['userid'], SQL_PARAMS_NAMED, 'iuid');
1009          $params = array_merge($params, $inparams);
1010          $iwheres[] = "iquiza.userid $incond";
1011      }
1012  
1013      if (isset($conditions['quizid'])) {
1014          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['quizid'], SQL_PARAMS_NAMED, 'qid');
1015          $params = array_merge($params, $inparams);
1016          $wheres[] = "quiza.quiz $incond";
1017          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['quizid'], SQL_PARAMS_NAMED, 'iqid');
1018          $params = array_merge($params, $inparams);
1019          $iwheres[] = "iquiza.quiz $incond";
1020      }
1021  
1022      if (isset($conditions['groupid'])) {
1023          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['groupid'], SQL_PARAMS_NAMED, 'gid');
1024          $params = array_merge($params, $inparams);
1025          $wheres[] = "quiza.quiz IN (SELECT qo.quiz FROM {quiz_overrides} qo WHERE qo.groupid $incond)";
1026          list ($incond, $inparams) = $DB->get_in_or_equal($conditions['groupid'], SQL_PARAMS_NAMED, 'igid');
1027          $params = array_merge($params, $inparams);
1028          $iwheres[] = "iquiza.quiz IN (SELECT qo.quiz FROM {quiz_overrides} qo WHERE qo.groupid $incond)";
1029      }
1030  
1031      // SQL to compute timeclose and timelimit for each attempt:
1032      $quizausersql = quiz_get_attempt_usertime_sql(
1033              implode("\n                AND ", $iwheres));
1034  
1035      // SQL to compute the new timecheckstate
1036      $timecheckstatesql = "
1037            CASE WHEN quizauser.usertimelimit = 0 AND quizauser.usertimeclose = 0 THEN NULL
1038                 WHEN quizauser.usertimelimit = 0 THEN quizauser.usertimeclose
1039                 WHEN quizauser.usertimeclose = 0 THEN quiza.timestart + quizauser.usertimelimit
1040                 WHEN quiza.timestart + quizauser.usertimelimit < quizauser.usertimeclose THEN quiza.timestart + quizauser.usertimelimit
1041                 ELSE quizauser.usertimeclose END +
1042            CASE WHEN quiza.state = 'overdue' THEN quiz.graceperiod ELSE 0 END";
1043  
1044      // SQL to select which attempts to process
1045      $attemptselect = implode("\n                         AND ", $wheres);
1046  
1047     /*
1048      * Each database handles updates with inner joins differently:
1049      *  - mysql does not allow a FROM clause
1050      *  - postgres and mssql allow FROM but handle table aliases differently
1051      *  - oracle requires a subquery
1052      *
1053      * Different code for each database.
1054      */
1055  
1056      $dbfamily = $DB->get_dbfamily();
1057      if ($dbfamily == 'mysql') {
1058          $updatesql = "UPDATE {quiz_attempts} quiza
1059                          JOIN {quiz} quiz ON quiz.id = quiza.quiz
1060                          JOIN ( $quizausersql ) quizauser ON quizauser.id = quiza.id
1061                           SET quiza.timecheckstate = $timecheckstatesql
1062                         WHERE $attemptselect";
1063      } else if ($dbfamily == 'postgres') {
1064          $updatesql = "UPDATE {quiz_attempts} quiza
1065                           SET timecheckstate = $timecheckstatesql
1066                          FROM {quiz} quiz, ( $quizausersql ) quizauser
1067                         WHERE quiz.id = quiza.quiz
1068                           AND quizauser.id = quiza.id
1069                           AND $attemptselect";
1070      } else if ($dbfamily == 'mssql') {
1071          $updatesql = "UPDATE quiza
1072                           SET timecheckstate = $timecheckstatesql
1073                          FROM {quiz_attempts} quiza
1074                          JOIN {quiz} quiz ON quiz.id = quiza.quiz
1075                          JOIN ( $quizausersql ) quizauser ON quizauser.id = quiza.id
1076                         WHERE $attemptselect";
1077      } else {
1078          // oracle, sqlite and others
1079          $updatesql = "UPDATE {quiz_attempts} quiza
1080                           SET timecheckstate = (
1081                             SELECT $timecheckstatesql
1082                               FROM {quiz} quiz, ( $quizausersql ) quizauser
1083                              WHERE quiz.id = quiza.quiz
1084                                AND quizauser.id = quiza.id
1085                           )
1086                           WHERE $attemptselect";
1087      }
1088  
1089      $DB->execute($updatesql, $params);
1090  }
1091  
1092  /**
1093   * Returns SQL to compute timeclose and timelimit for every attempt, taking into account user and group overrides.
1094   * The query used herein is very similar to the one in function quiz_get_user_timeclose, so, in case you
1095   * would change either one of them, make sure to apply your changes to both.
1096   *
1097   * @param string $redundantwhereclauses extra where clauses to add to the subquery
1098   *      for performance. These can use the table alias iquiza for the quiz attempts table.
1099   * @return string SQL select with columns attempt.id, usertimeclose, usertimelimit.
1100   */
1101  function quiz_get_attempt_usertime_sql($redundantwhereclauses = '') {
1102      if ($redundantwhereclauses) {
1103          $redundantwhereclauses = 'WHERE ' . $redundantwhereclauses;
1104      }
1105      // The multiple qgo JOINS are necessary because we want timeclose/timelimit = 0 (unlimited) to supercede
1106      // any other group override
1107      $quizausersql = "
1108            SELECT iquiza.id,
1109             COALESCE(MAX(quo.timeclose), MAX(qgo1.timeclose), MAX(qgo2.timeclose), iquiz.timeclose) AS usertimeclose,
1110             COALESCE(MAX(quo.timelimit), MAX(qgo3.timelimit), MAX(qgo4.timelimit), iquiz.timelimit) AS usertimelimit
1111  
1112             FROM {quiz_attempts} iquiza
1113             JOIN {quiz} iquiz ON iquiz.id = iquiza.quiz
1114        LEFT JOIN {quiz_overrides} quo ON quo.quiz = iquiza.quiz AND quo.userid = iquiza.userid
1115        LEFT JOIN {groups_members} gm ON gm.userid = iquiza.userid
1116        LEFT JOIN {quiz_overrides} qgo1 ON qgo1.quiz = iquiza.quiz AND qgo1.groupid = gm.groupid AND qgo1.timeclose = 0
1117        LEFT JOIN {quiz_overrides} qgo2 ON qgo2.quiz = iquiza.quiz AND qgo2.groupid = gm.groupid AND qgo2.timeclose > 0
1118        LEFT JOIN {quiz_overrides} qgo3 ON qgo3.quiz = iquiza.quiz AND qgo3.groupid = gm.groupid AND qgo3.timelimit = 0
1119        LEFT JOIN {quiz_overrides} qgo4 ON qgo4.quiz = iquiza.quiz AND qgo4.groupid = gm.groupid AND qgo4.timelimit > 0
1120            $redundantwhereclauses
1121         GROUP BY iquiza.id, iquiz.id, iquiz.timeclose, iquiz.timelimit";
1122      return $quizausersql;
1123  }
1124  
1125  /**
1126   * Return the attempt with the best grade for a quiz
1127   *
1128   * Which attempt is the best depends on $quiz->grademethod. If the grade
1129   * method is GRADEAVERAGE then this function simply returns the last attempt.
1130   * @return object         The attempt with the best grade
1131   * @param object $quiz    The quiz for which the best grade is to be calculated
1132   * @param array $attempts An array of all the attempts of the user at the quiz
1133   */
1134  function quiz_calculate_best_attempt($quiz, $attempts) {
1135  
1136      switch ($quiz->grademethod) {
1137  
1138          case QUIZ_ATTEMPTFIRST:
1139              foreach ($attempts as $attempt) {
1140                  return $attempt;
1141              }
1142              break;
1143  
1144          case QUIZ_GRADEAVERAGE: // We need to do something with it.
1145          case QUIZ_ATTEMPTLAST:
1146              foreach ($attempts as $attempt) {
1147                  $final = $attempt;
1148              }
1149              return $final;
1150  
1151          default:
1152          case QUIZ_GRADEHIGHEST:
1153              $max = -1;
1154              foreach ($attempts as $attempt) {
1155                  if ($attempt->sumgrades > $max) {
1156                      $max = $attempt->sumgrades;
1157                      $maxattempt = $attempt;
1158                  }
1159              }
1160              return $maxattempt;
1161      }
1162  }
1163  
1164  /**
1165   * @return array int => lang string the options for calculating the quiz grade
1166   *      from the individual attempt grades.
1167   */
1168  function quiz_get_grading_options() {
1169      return array(
1170          QUIZ_GRADEHIGHEST => get_string('gradehighest', 'quiz'),
1171          QUIZ_GRADEAVERAGE => get_string('gradeaverage', 'quiz'),
1172          QUIZ_ATTEMPTFIRST => get_string('attemptfirst', 'quiz'),
1173          QUIZ_ATTEMPTLAST  => get_string('attemptlast', 'quiz')
1174      );
1175  }
1176  
1177  /**
1178   * @param int $option one of the values QUIZ_GRADEHIGHEST, QUIZ_GRADEAVERAGE,
1179   *      QUIZ_ATTEMPTFIRST or QUIZ_ATTEMPTLAST.
1180   * @return the lang string for that option.
1181   */
1182  function quiz_get_grading_option_name($option) {
1183      $strings = quiz_get_grading_options();
1184      return $strings[$option];
1185  }
1186  
1187  /**
1188   * @return array string => lang string the options for handling overdue quiz
1189   *      attempts.
1190   */
1191  function quiz_get_overdue_handling_options() {
1192      return array(
1193          'autosubmit'  => get_string('overduehandlingautosubmit', 'quiz'),
1194          'graceperiod' => get_string('overduehandlinggraceperiod', 'quiz'),
1195          'autoabandon' => get_string('overduehandlingautoabandon', 'quiz'),
1196      );
1197  }
1198  
1199  /**
1200   * Get the choices for what size user picture to show.
1201   * @return array string => lang string the options for whether to display the user's picture.
1202   */
1203  function quiz_get_user_image_options() {
1204      return array(
1205          QUIZ_SHOWIMAGE_NONE  => get_string('shownoimage', 'quiz'),
1206          QUIZ_SHOWIMAGE_SMALL => get_string('showsmallimage', 'quiz'),
1207          QUIZ_SHOWIMAGE_LARGE => get_string('showlargeimage', 'quiz'),
1208      );
1209  }
1210  
1211  /**
1212   * Return an user's timeclose for all quizzes in a course, hereby taking into account group and user overrides.
1213   *
1214   * @param int $courseid the course id.
1215   * @return object An object with of all quizids and close unixdates in this course, taking into account the most lenient
1216   * overrides, if existing and 0 if no close date is set.
1217   */
1218  function quiz_get_user_timeclose($courseid) {
1219      global $DB, $USER;
1220  
1221      // For teacher and manager/admins return timeclose.
1222      if (has_capability('moodle/course:update', context_course::instance($courseid))) {
1223          $sql = "SELECT quiz.id, quiz.timeclose AS usertimeclose
1224                    FROM {quiz} quiz
1225                   WHERE quiz.course = :courseid";
1226  
1227          $results = $DB->get_records_sql($sql, array('courseid' => $courseid));
1228          return $results;
1229      }
1230  
1231      $sql = "SELECT q.id,
1232    COALESCE(v.userclose, v.groupclose, q.timeclose, 0) AS usertimeclose
1233    FROM (
1234        SELECT quiz.id as quizid,
1235               MAX(quo.timeclose) AS userclose, MAX(qgo.timeclose) AS groupclose
1236         FROM {quiz} quiz
1237    LEFT JOIN {quiz_overrides} quo on quiz.id = quo.quiz AND quo.userid = :userid
1238    LEFT JOIN {groups_members} gm ON gm.userid = :useringroupid
1239    LEFT JOIN {quiz_overrides} qgo on quiz.id = qgo.quiz AND qgo.groupid = gm.groupid
1240        WHERE quiz.course = :courseid
1241     GROUP BY quiz.id) v
1242         JOIN {quiz} q ON q.id = v.quizid";
1243  
1244      $results = $DB->get_records_sql($sql, array('userid' => $USER->id, 'useringroupid' => $USER->id, 'courseid' => $courseid));
1245      return $results;
1246  
1247  }
1248  
1249  /**
1250   * Get the choices to offer for the 'Questions per page' option.
1251   * @return array int => string.
1252   */
1253  function quiz_questions_per_page_options() {
1254      $pageoptions = array();
1255      $pageoptions[0] = get_string('neverallononepage', 'quiz');
1256      $pageoptions[1] = get_string('everyquestion', 'quiz');
1257      for ($i = 2; $i <= QUIZ_MAX_QPP_OPTION; ++$i) {
1258          $pageoptions[$i] = get_string('everynquestions', 'quiz', $i);
1259      }
1260      return $pageoptions;
1261  }
1262  
1263  /**
1264   * Get the human-readable name for a quiz attempt state.
1265   * @param string $state one of the state constants like {@link quiz_attempt::IN_PROGRESS}.
1266   * @return string The lang string to describe that state.
1267   */
1268  function quiz_attempt_state_name($state) {
1269      switch ($state) {
1270          case quiz_attempt::IN_PROGRESS:
1271              return get_string('stateinprogress', 'quiz');
1272          case quiz_attempt::OVERDUE:
1273              return get_string('stateoverdue', 'quiz');
1274          case quiz_attempt::FINISHED:
1275              return get_string('statefinished', 'quiz');
1276          case quiz_attempt::ABANDONED:
1277              return get_string('stateabandoned', 'quiz');
1278          default:
1279              throw new coding_exception('Unknown quiz attempt state.');
1280      }
1281  }
1282  
1283  // Other quiz functions ////////////////////////////////////////////////////////
1284  
1285  /**
1286   * @param object $quiz the quiz.
1287   * @param int $cmid the course_module object for this quiz.
1288   * @param object $question the question.
1289   * @param string $returnurl url to return to after action is done.
1290   * @param int $variant which question variant to preview (optional).
1291   * @return string html for a number of icons linked to action pages for a
1292   * question - preview and edit / view icons depending on user capabilities.
1293   */
1294  function quiz_question_action_icons($quiz, $cmid, $question, $returnurl, $variant = null) {
1295      $html = quiz_question_preview_button($quiz, $question, false, $variant) . ' ' .
1296              quiz_question_edit_button($cmid, $question, $returnurl);
1297      return $html;
1298  }
1299  
1300  /**
1301   * @param int $cmid the course_module.id for this quiz.
1302   * @param object $question the question.
1303   * @param string $returnurl url to return to after action is done.
1304   * @param string $contentbeforeicon some HTML content to be added inside the link, before the icon.
1305   * @return the HTML for an edit icon, view icon, or nothing for a question
1306   *      (depending on permissions).
1307   */
1308  function quiz_question_edit_button($cmid, $question, $returnurl, $contentaftericon = '') {
1309      global $CFG, $OUTPUT;
1310  
1311      // Minor efficiency saving. Only get strings once, even if there are a lot of icons on one page.
1312      static $stredit = null;
1313      static $strview = null;
1314      if ($stredit === null) {
1315          $stredit = get_string('edit');
1316          $strview = get_string('view');
1317      }
1318  
1319      // What sort of icon should we show?
1320      $action = '';
1321      if (!empty($question->id) &&
1322              (question_has_capability_on($question, 'edit') ||
1323                      question_has_capability_on($question, 'move'))) {
1324          $action = $stredit;
1325          $icon = 't/edit';
1326      } else if (!empty($question->id) &&
1327              question_has_capability_on($question, 'view')) {
1328          $action = $strview;
1329          $icon = 'i/info';
1330      }
1331  
1332      // Build the icon.
1333      if ($action) {
1334          if ($returnurl instanceof moodle_url) {
1335              $returnurl = $returnurl->out_as_local_url(false);
1336          }
1337          $questionparams = array('returnurl' => $returnurl, 'cmid' => $cmid, 'id' => $question->id);
1338          $questionurl = new moodle_url("$CFG->wwwroot/question/question.php", $questionparams);
1339          return '<a title="' . $action . '" href="' . $questionurl->out() . '" class="questioneditbutton">' .
1340                  $OUTPUT->pix_icon($icon, $action) . $contentaftericon .
1341                  '</a>';
1342      } else if ($contentaftericon) {
1343          return '<span class="questioneditbutton">' . $contentaftericon . '</span>';
1344      } else {
1345          return '';
1346      }
1347  }
1348  
1349  /**
1350   * @param object $quiz the quiz settings
1351   * @param object $question the question
1352   * @param int $variant which question variant to preview (optional).
1353   * @return moodle_url to preview this question with the options from this quiz.
1354   */
1355  function quiz_question_preview_url($quiz, $question, $variant = null) {
1356      // Get the appropriate display options.
1357      $displayoptions = mod_quiz_display_options::make_from_quiz($quiz,
1358              mod_quiz_display_options::DURING);
1359  
1360      $maxmark = null;
1361      if (isset($question->maxmark)) {
1362          $maxmark = $question->maxmark;
1363      }
1364  
1365      // Work out the correcte preview URL.
1366      return question_preview_url($question->id, $quiz->preferredbehaviour,
1367              $maxmark, $displayoptions, $variant);
1368  }
1369  
1370  /**
1371   * @param object $quiz the quiz settings
1372   * @param object $question the question
1373   * @param bool $label if true, show the preview question label after the icon
1374   * @param int $variant which question variant to preview (optional).
1375   * @return the HTML for a preview question icon.
1376   */
1377  function quiz_question_preview_button($quiz, $question, $label = false, $variant = null) {
1378      global $PAGE;
1379      if (!question_has_capability_on($question, 'use')) {
1380          return '';
1381      }
1382  
1383      return $PAGE->get_renderer('mod_quiz', 'edit')->question_preview_icon($quiz, $question, $label, $variant);
1384  }
1385  
1386  /**
1387   * @param object $attempt the attempt.
1388   * @param object $context the quiz context.
1389   * @return int whether flags should be shown/editable to the current user for this attempt.
1390   */
1391  function quiz_get_flag_option($attempt, $context) {
1392      global $USER;
1393      if (!has_capability('moodle/question:flag', $context)) {
1394          return question_display_options::HIDDEN;
1395      } else if ($attempt->userid == $USER->id) {
1396          return question_display_options::EDITABLE;
1397      } else {
1398          return question_display_options::VISIBLE;
1399      }
1400  }
1401  
1402  /**
1403   * Work out what state this quiz attempt is in - in the sense used by
1404   * quiz_get_review_options, not in the sense of $attempt->state.
1405   * @param object $quiz the quiz settings
1406   * @param object $attempt the quiz_attempt database row.
1407   * @return int one of the mod_quiz_display_options::DURING,
1408   *      IMMEDIATELY_AFTER, LATER_WHILE_OPEN or AFTER_CLOSE constants.
1409   */
1410  function quiz_attempt_state($quiz, $attempt) {
1411      if ($attempt->state == quiz_attempt::IN_PROGRESS) {
1412          return mod_quiz_display_options::DURING;
1413      } else if ($quiz->timeclose && time() >= $quiz->timeclose) {
1414          return mod_quiz_display_options::AFTER_CLOSE;
1415      } else if (time() < $attempt->timefinish + 120) {
1416          return mod_quiz_display_options::IMMEDIATELY_AFTER;
1417      } else {
1418          return mod_quiz_display_options::LATER_WHILE_OPEN;
1419      }
1420  }
1421  
1422  /**
1423   * The the appropraite mod_quiz_display_options object for this attempt at this
1424   * quiz right now.
1425   *
1426   * @param stdClass $quiz the quiz instance.
1427   * @param stdClass $attempt the attempt in question.
1428   * @param context $context the quiz context.
1429   *
1430   * @return mod_quiz_display_options
1431   */
1432  function quiz_get_review_options($quiz, $attempt, $context) {
1433      $options = mod_quiz_display_options::make_from_quiz($quiz, quiz_attempt_state($quiz, $attempt));
1434  
1435      $options->readonly = true;
1436      $options->flags = quiz_get_flag_option($attempt, $context);
1437      if (!empty($attempt->id)) {
1438          $options->questionreviewlink = new moodle_url('/mod/quiz/reviewquestion.php',
1439                  array('attempt' => $attempt->id));
1440      }
1441  
1442      // Show a link to the comment box only for closed attempts.
1443      if (!empty($attempt->id) && $attempt->state == quiz_attempt::FINISHED && !$attempt->preview &&
1444              !is_null($context) && has_capability('mod/quiz:grade', $context)) {
1445          $options->manualcomment = question_display_options::VISIBLE;
1446          $options->manualcommentlink = new moodle_url('/mod/quiz/comment.php',
1447                  array('attempt' => $attempt->id));
1448      }
1449  
1450      if (!is_null($context) && !$attempt->preview &&
1451              has_capability('mod/quiz:viewreports', $context) &&
1452              has_capability('moodle/grade:viewhidden', $context)) {
1453          // People who can see reports and hidden grades should be shown everything,
1454          // except during preview when teachers want to see what students see.
1455          $options->attempt = question_display_options::VISIBLE;
1456          $options->correctness = question_display_options::VISIBLE;
1457          $options->marks = question_display_options::MARK_AND_MAX;
1458          $options->feedback = question_display_options::VISIBLE;
1459          $options->numpartscorrect = question_display_options::VISIBLE;
1460          $options->manualcomment = question_display_options::VISIBLE;
1461          $options->generalfeedback = question_display_options::VISIBLE;
1462          $options->rightanswer = question_display_options::VISIBLE;
1463          $options->overallfeedback = question_display_options::VISIBLE;
1464          $options->history = question_display_options::VISIBLE;
1465  
1466      }
1467  
1468      return $options;
1469  }
1470  
1471  /**
1472   * Combines the review options from a number of different quiz attempts.
1473   * Returns an array of two ojects, so the suggested way of calling this
1474   * funciton is:
1475   * list($someoptions, $alloptions) = quiz_get_combined_reviewoptions(...)
1476   *
1477   * @param object $quiz the quiz instance.
1478   * @param array $attempts an array of attempt objects.
1479   *
1480   * @return array of two options objects, one showing which options are true for
1481   *          at least one of the attempts, the other showing which options are true
1482   *          for all attempts.
1483   */
1484  function quiz_get_combined_reviewoptions($quiz, $attempts) {
1485      $fields = array('feedback', 'generalfeedback', 'rightanswer', 'overallfeedback');
1486      $someoptions = new stdClass();
1487      $alloptions = new stdClass();
1488      foreach ($fields as $field) {
1489          $someoptions->$field = false;
1490          $alloptions->$field = true;
1491      }
1492      $someoptions->marks = question_display_options::HIDDEN;
1493      $alloptions->marks = question_display_options::MARK_AND_MAX;
1494  
1495      // This shouldn't happen, but we need to prevent reveal information.
1496      if (empty($attempts)) {
1497          return array($someoptions, $someoptions);
1498      }
1499  
1500      foreach ($attempts as $attempt) {
1501          $attemptoptions = mod_quiz_display_options::make_from_quiz($quiz,
1502                  quiz_attempt_state($quiz, $attempt));
1503          foreach ($fields as $field) {
1504              $someoptions->$field = $someoptions->$field || $attemptoptions->$field;
1505              $alloptions->$field = $alloptions->$field && $attemptoptions->$field;
1506          }
1507          $someoptions->marks = max($someoptions->marks, $attemptoptions->marks);
1508          $alloptions->marks = min($alloptions->marks, $attemptoptions->marks);
1509      }
1510      return array($someoptions, $alloptions);
1511  }
1512  
1513  // Functions for sending notification messages /////////////////////////////////
1514  
1515  /**
1516   * Sends a confirmation message to the student confirming that the attempt was processed.
1517   *
1518   * @param object $a lots of useful information that can be used in the message
1519   *      subject and body.
1520   *
1521   * @return int|false as for {@link message_send()}.
1522   */
1523  function quiz_send_confirmation($recipient, $a) {
1524  
1525      // Add information about the recipient to $a.
1526      // Don't do idnumber. we want idnumber to be the submitter's idnumber.
1527      $a->username     = fullname($recipient);
1528      $a->userusername = $recipient->username;
1529  
1530      // Prepare the message.
1531      $eventdata = new \core\message\message();
1532      $eventdata->courseid          = $a->courseid;
1533      $eventdata->component         = 'mod_quiz';
1534      $eventdata->name              = 'confirmation';
1535      $eventdata->notification      = 1;
1536  
1537      $eventdata->userfrom          = core_user::get_noreply_user();
1538      $eventdata->userto            = $recipient;
1539      $eventdata->subject           = get_string('emailconfirmsubject', 'quiz', $a);
1540      $eventdata->fullmessage       = get_string('emailconfirmbody', 'quiz', $a);
1541      $eventdata->fullmessageformat = FORMAT_PLAIN;
1542      $eventdata->fullmessagehtml   = '';
1543  
1544      $eventdata->smallmessage      = get_string('emailconfirmsmall', 'quiz', $a);
1545      $eventdata->contexturl        = $a->quizurl;
1546      $eventdata->contexturlname    = $a->quizname;
1547      $eventdata->customdata        = [
1548          'cmid' => $a->quizcmid,
1549          'instance' => $a->quizid,
1550          'attemptid' => $a->attemptid,
1551      ];
1552  
1553      // ... and send it.
1554      return message_send($eventdata);
1555  }
1556  
1557  /**
1558   * Sends notification messages to the interested parties that assign the role capability
1559   *
1560   * @param object $recipient user object of the intended recipient
1561   * @param object $a associative array of replaceable fields for the templates
1562   *
1563   * @return int|false as for {@link message_send()}.
1564   */
1565  function quiz_send_notification($recipient, $submitter, $a) {
1566      global $PAGE;
1567  
1568      // Recipient info for template.
1569      $a->useridnumber = $recipient->idnumber;
1570      $a->username     = fullname($recipient);
1571      $a->userusername = $recipient->username;
1572  
1573      // Prepare the message.
1574      $eventdata = new \core\message\message();
1575      $eventdata->courseid          = $a->courseid;
1576      $eventdata->component         = 'mod_quiz';
1577      $eventdata->name              = 'submission';
1578      $eventdata->notification      = 1;
1579  
1580      $eventdata->userfrom          = $submitter;
1581      $eventdata->userto            = $recipient;
1582      $eventdata->subject           = get_string('emailnotifysubject', 'quiz', $a);
1583      $eventdata->fullmessage       = get_string('emailnotifybody', 'quiz', $a);
1584      $eventdata->fullmessageformat = FORMAT_PLAIN;
1585      $eventdata->fullmessagehtml   = '';
1586  
1587      $eventdata->smallmessage      = get_string('emailnotifysmall', 'quiz', $a);
1588      $eventdata->contexturl        = $a->quizreviewurl;
1589      $eventdata->contexturlname    = $a->quizname;
1590      $userpicture = new user_picture($submitter);
1591      $userpicture->size = 1; // Use f1 size.
1592      $userpicture->includetoken = $recipient->id; // Generate an out-of-session token for the user receiving the message.
1593      $eventdata->customdata        = [
1594          'cmid' => $a->quizcmid,
1595          'instance' => $a->quizid,
1596          'attemptid' => $a->attemptid,
1597          'notificationiconurl' => $userpicture->get_url($PAGE)->out(false),
1598      ];
1599  
1600      // ... and send it.
1601      return message_send($eventdata);
1602  }
1603  
1604  /**
1605   * Send all the requried messages when a quiz attempt is submitted.
1606   *
1607   * @param object $course the course
1608   * @param object $quiz the quiz
1609   * @param object $attempt this attempt just finished
1610   * @param object $context the quiz context
1611   * @param object $cm the coursemodule for this quiz
1612   *
1613   * @return bool true if all necessary messages were sent successfully, else false.
1614   */
1615  function quiz_send_notification_messages($course, $quiz, $attempt, $context, $cm) {
1616      global $CFG, $DB;
1617  
1618      // Do nothing if required objects not present.
1619      if (empty($course) or empty($quiz) or empty($attempt) or empty($context)) {
1620          throw new coding_exception('$course, $quiz, $attempt, $context and $cm must all be set.');
1621      }
1622  
1623      $submitter = $DB->get_record('user', array('id' => $attempt->userid), '*', MUST_EXIST);
1624  
1625      // Check for confirmation required.
1626      $sendconfirm = false;
1627      $notifyexcludeusers = '';
1628      if (has_capability('mod/quiz:emailconfirmsubmission', $context, $submitter, false)) {
1629          $notifyexcludeusers = $submitter->id;
1630          $sendconfirm = true;
1631      }
1632  
1633      // Check for notifications required.
1634      $notifyfields = 'u.id, u.username, u.idnumber, u.email, u.emailstop, u.lang,
1635              u.timezone, u.mailformat, u.maildisplay, u.auth, u.suspended, u.deleted, ';
1636      $notifyfields .= get_all_user_name_fields(true, 'u');
1637      $groups = groups_get_all_groups($course->id, $submitter->id, $cm->groupingid);
1638      if (is_array($groups) && count($groups) > 0) {
1639          $groups = array_keys($groups);
1640      } else if (groups_get_activity_groupmode($cm, $course) != NOGROUPS) {
1641          // If the user is not in a group, and the quiz is set to group mode,
1642          // then set $groups to a non-existant id so that only users with
1643          // 'moodle/site:accessallgroups' get notified.
1644          $groups = -1;
1645      } else {
1646          $groups = '';
1647      }
1648      $userstonotify = get_users_by_capability($context, 'mod/quiz:emailnotifysubmission',
1649              $notifyfields, '', '', '', $groups, $notifyexcludeusers, false, false, true);
1650  
1651      if (empty($userstonotify) && !$sendconfirm) {
1652          return true; // Nothing to do.
1653      }
1654  
1655      $a = new stdClass();
1656      // Course info.
1657      $a->courseid        = $course->id;
1658      $a->coursename      = $course->fullname;
1659      $a->courseshortname = $course->shortname;
1660      // Quiz info.
1661      $a->quizname        = $quiz->name;
1662      $a->quizreporturl   = $CFG->wwwroot . '/mod/quiz/report.php?id=' . $cm->id;
1663      $a->quizreportlink  = '<a href="' . $a->quizreporturl . '">' .
1664              format_string($quiz->name) . ' report</a>';
1665      $a->quizurl         = $CFG->wwwroot . '/mod/quiz/view.php?id=' . $cm->id;
1666      $a->quizlink        = '<a href="' . $a->quizurl . '">' . format_string($quiz->name) . '</a>';
1667      $a->quizid          = $quiz->id;
1668      $a->quizcmid        = $cm->id;
1669      // Attempt info.
1670      $a->submissiontime  = userdate($attempt->timefinish);
1671      $a->timetaken       = format_time($attempt->timefinish - $attempt->timestart);
1672      $a->quizreviewurl   = $CFG->wwwroot . '/mod/quiz/review.php?attempt=' . $attempt->id;
1673      $a->quizreviewlink  = '<a href="' . $a->quizreviewurl . '">' .
1674              format_string($quiz->name) . ' review</a>';
1675      $a->attemptid       = $attempt->id;
1676      // Student who sat the quiz info.
1677      $a->studentidnumber = $submitter->idnumber;
1678      $a->studentname     = fullname($submitter);
1679      $a->studentusername = $submitter->username;
1680  
1681      $allok = true;
1682  
1683      // Send notifications if required.
1684      if (!empty($userstonotify)) {
1685          foreach ($userstonotify as $recipient) {
1686              $allok = $allok && quiz_send_notification($recipient, $submitter, $a);
1687          }
1688      }
1689  
1690      // Send confirmation if required. We send the student confirmation last, so
1691      // that if message sending is being intermittently buggy, which means we send
1692      // some but not all messages, and then try again later, then teachers may get
1693      // duplicate messages, but the student will always get exactly one.
1694      if ($sendconfirm) {
1695          $allok = $allok && quiz_send_confirmation($submitter, $a);
1696      }
1697  
1698      return $allok;
1699  }
1700  
1701  /**
1702   * Send the notification message when a quiz attempt becomes overdue.
1703   *
1704   * @param quiz_attempt $attemptobj all the data about the quiz attempt.
1705   */
1706  function quiz_send_overdue_message($attemptobj) {
1707      global $CFG, $DB;
1708  
1709      $submitter = $DB->get_record('user', array('id' => $attemptobj->get_userid()), '*', MUST_EXIST);
1710  
1711      if (!$attemptobj->has_capability('mod/quiz:emailwarnoverdue', $submitter->id, false)) {
1712          return; // Message not required.
1713      }
1714  
1715      if (!$attemptobj->has_response_to_at_least_one_graded_question()) {
1716          return; // Message not required.
1717      }
1718  
1719      // Prepare lots of useful information that admins might want to include in
1720      // the email message.
1721      $quizname = format_string($attemptobj->get_quiz_name());
1722  
1723      $deadlines = array();
1724      if ($attemptobj->get_quiz()->timelimit) {
1725          $deadlines[] = $attemptobj->get_attempt()->timestart + $attemptobj->get_quiz()->timelimit;
1726      }
1727      if ($attemptobj->get_quiz()->timeclose) {
1728          $deadlines[] = $attemptobj->get_quiz()->timeclose;
1729      }
1730      $duedate = min($deadlines);
1731      $graceend = $duedate + $attemptobj->get_quiz()->graceperiod;
1732  
1733      $a = new stdClass();
1734      // Course info.
1735      $a->courseid           = $attemptobj->get_course()->id;
1736      $a->coursename         = format_string($attemptobj->get_course()->fullname);
1737      $a->courseshortname    = format_string($attemptobj->get_course()->shortname);
1738      // Quiz info.
1739      $a->quizname           = $quizname;
1740      $a->quizurl            = $attemptobj->view_url();
1741      $a->quizlink           = '<a href="' . $a->quizurl . '">' . $quizname . '</a>';
1742      // Attempt info.
1743      $a->attemptduedate     = userdate($duedate);
1744      $a->attemptgraceend    = userdate($graceend);
1745      $a->attemptsummaryurl  = $attemptobj->summary_url()->out(false);
1746      $a->attemptsummarylink = '<a href="' . $a->attemptsummaryurl . '">' . $quizname . ' review</a>';
1747      // Student's info.
1748      $a->studentidnumber    = $submitter->idnumber;
1749      $a->studentname        = fullname($submitter);
1750      $a->studentusername    = $submitter->username;
1751  
1752      // Prepare the message.
1753      $eventdata = new \core\message\message();
1754      $eventdata->courseid          = $a->courseid;
1755      $eventdata->component         = 'mod_quiz';
1756      $eventdata->name              = 'attempt_overdue';
1757      $eventdata->notification      = 1;
1758  
1759      $eventdata->userfrom          = core_user::get_noreply_user();
1760      $eventdata->userto            = $submitter;
1761      $eventdata->subject           = get_string('emailoverduesubject', 'quiz', $a);
1762      $eventdata->fullmessage       = get_string('emailoverduebody', 'quiz', $a);
1763      $eventdata->fullmessageformat = FORMAT_PLAIN;
1764      $eventdata->fullmessagehtml   = '';
1765  
1766      $eventdata->smallmessage      = get_string('emailoverduesmall', 'quiz', $a);
1767      $eventdata->contexturl        = $a->quizurl;
1768      $eventdata->contexturlname    = $a->quizname;
1769      $eventdata->customdata        = [
1770          'cmid' => $attemptobj->get_cmid(),
1771          'instance' => $attemptobj->get_quizid(),
1772          'attemptid' => $attemptobj->get_attemptid(),
1773      ];
1774  
1775      // Send the message.
1776      return message_send($eventdata);
1777  }
1778  
1779  /**
1780   * Handle the quiz_attempt_submitted event.
1781   *
1782   * This sends the confirmation and notification messages, if required.
1783   *
1784   * @param object $event the event object.
1785   */
1786  function quiz_attempt_submitted_handler($event) {
1787      global $DB;
1788  
1789      $course  = $DB->get_record('course', array('id' => $event->courseid));
1790      $attempt = $event->get_record_snapshot('quiz_attempts', $event->objectid);
1791      $quiz    = $event->get_record_snapshot('quiz', $attempt->quiz);
1792      $cm      = get_coursemodule_from_id('quiz', $event->get_context()->instanceid, $event->courseid);
1793  
1794      if (!($course && $quiz && $cm && $attempt)) {
1795          // Something has been deleted since the event was raised. Therefore, the
1796          // event is no longer relevant.
1797          return true;
1798      }
1799  
1800      // Update completion state.
1801      $completion = new completion_info($course);
1802      if ($completion->is_enabled($cm) && ($quiz->completionattemptsexhausted || $quiz->completionpass)) {
1803          $completion->update_state($cm, COMPLETION_COMPLETE, $event->userid);
1804      }
1805      return quiz_send_notification_messages($course, $quiz, $attempt,
1806              context_module::instance($cm->id), $cm);
1807  }
1808  
1809  /**
1810   * Handle groups_member_added event
1811   *
1812   * @param object $event the event object.
1813   * @deprecated since 2.6, see {@link \mod_quiz\group_observers::group_member_added()}.
1814   */
1815  function quiz_groups_member_added_handler($event) {
1816      debugging('quiz_groups_member_added_handler() is deprecated, please use ' .
1817          '\mod_quiz\group_observers::group_member_added() instead.', DEBUG_DEVELOPER);
1818      quiz_update_open_attempts(array('userid'=>$event->userid, 'groupid'=>$event->groupid));
1819  }
1820  
1821  /**
1822   * Handle groups_member_removed event
1823   *
1824   * @param object $event the event object.
1825   * @deprecated since 2.6, see {@link \mod_quiz\group_observers::group_member_removed()}.
1826   */
1827  function quiz_groups_member_removed_handler($event) {
1828      debugging('quiz_groups_member_removed_handler() is deprecated, please use ' .
1829          '\mod_quiz\group_observers::group_member_removed() instead.', DEBUG_DEVELOPER);
1830      quiz_update_open_attempts(array('userid'=>$event->userid, 'groupid'=>$event->groupid));
1831  }
1832  
1833  /**
1834   * Handle groups_group_deleted event
1835   *
1836   * @param object $event the event object.
1837   * @deprecated since 2.6, see {@link \mod_quiz\group_observers::group_deleted()}.
1838   */
1839  function quiz_groups_group_deleted_handler($event) {
1840      global $DB;
1841      debugging('quiz_groups_group_deleted_handler() is deprecated, please use ' .
1842          '\mod_quiz\group_observers::group_deleted() instead.', DEBUG_DEVELOPER);
1843      quiz_process_group_deleted_in_course($event->courseid);
1844  }
1845  
1846  /**
1847   * Logic to happen when a/some group(s) has/have been deleted in a course.
1848   *
1849   * @param int $courseid The course ID.
1850   * @return void
1851   */
1852  function quiz_process_group_deleted_in_course($courseid) {
1853      global $DB;
1854  
1855      // It would be nice if we got the groupid that was deleted.
1856      // Instead, we just update all quizzes with orphaned group overrides.
1857      $sql = "SELECT o.id, o.quiz
1858                FROM {quiz_overrides} o
1859                JOIN {quiz} quiz ON quiz.id = o.quiz
1860           LEFT JOIN {groups} grp ON grp.id = o.groupid
1861               WHERE quiz.course = :courseid
1862                 AND o.groupid IS NOT NULL
1863                 AND grp.id IS NULL";
1864      $params = array('courseid' => $courseid);
1865      $records = $DB->get_records_sql_menu($sql, $params);
1866      if (!$records) {
1867          return; // Nothing to do.
1868      }
1869      $DB->delete_records_list('quiz_overrides', 'id', array_keys($records));
1870      quiz_update_open_attempts(array('quizid' => array_unique(array_values($records))));
1871  }
1872  
1873  /**
1874   * Handle groups_members_removed event
1875   *
1876   * @param object $event the event object.
1877   * @deprecated since 2.6, see {@link \mod_quiz\group_observers::group_member_removed()}.
1878   */
1879  function quiz_groups_members_removed_handler($event) {
1880      debugging('quiz_groups_members_removed_handler() is deprecated, please use ' .
1881          '\mod_quiz\group_observers::group_member_removed() instead.', DEBUG_DEVELOPER);
1882      if ($event->userid == 0) {
1883          quiz_update_open_attempts(array('courseid'=>$event->courseid));
1884      } else {
1885          quiz_update_open_attempts(array('courseid'=>$event->courseid, 'userid'=>$event->userid));
1886      }
1887  }
1888  
1889  /**
1890   * Get the information about the standard quiz JavaScript module.
1891   * @return array a standard jsmodule structure.
1892   */
1893  function quiz_get_js_module() {
1894      global $PAGE;
1895  
1896      return array(
1897          'name' => 'mod_quiz',
1898          'fullpath' => '/mod/quiz/module.js',
1899          'requires' => array('base', 'dom', 'event-delegate', 'event-key',
1900                  'core_question_engine', 'moodle-core-formchangechecker'),
1901          'strings' => array(
1902              array('cancel', 'moodle'),
1903              array('flagged', 'question'),
1904              array('functiondisabledbysecuremode', 'quiz'),
1905              array('startattempt', 'quiz'),
1906              array('timesup', 'quiz'),
1907              array('changesmadereallygoaway', 'moodle'),
1908          ),
1909      );
1910  }
1911  
1912  
1913  /**
1914   * An extension of question_display_options that includes the extra options used
1915   * by the quiz.
1916   *
1917   * @copyright  2010 The Open University
1918   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1919   */
1920  class mod_quiz_display_options extends question_display_options {
1921      /**#@+
1922       * @var integer bits used to indicate various times in relation to a
1923       * quiz attempt.
1924       */
1925      const DURING =            0x10000;
1926      const IMMEDIATELY_AFTER = 0x01000;
1927      const LATER_WHILE_OPEN =  0x00100;
1928      const AFTER_CLOSE =       0x00010;
1929      /**#@-*/
1930  
1931      /**
1932       * @var boolean if this is false, then the student is not allowed to review
1933       * anything about the attempt.
1934       */
1935      public $attempt = true;
1936  
1937      /**
1938       * @var boolean if this is false, then the student is not allowed to review
1939       * anything about the attempt.
1940       */
1941      public $overallfeedback = self::VISIBLE;
1942  
1943      /**
1944       * Set up the various options from the quiz settings, and a time constant.
1945       * @param object $quiz the quiz settings.
1946       * @param int $one of the {@link DURING}, {@link IMMEDIATELY_AFTER},
1947       * {@link LATER_WHILE_OPEN} or {@link AFTER_CLOSE} constants.
1948       * @return mod_quiz_display_options set up appropriately.
1949       */
1950      public static function make_from_quiz($quiz, $when) {
1951          $options = new self();
1952  
1953          $options->attempt = self::extract($quiz->reviewattempt, $when, true, false);
1954          $options->correctness = self::extract($quiz->reviewcorrectness, $when);
1955          $options->marks = self::extract($quiz->reviewmarks, $when,
1956                  self::MARK_AND_MAX, self::MAX_ONLY);
1957          $options->feedback = self::extract($quiz->reviewspecificfeedback, $when);
1958          $options->generalfeedback = self::extract($quiz->reviewgeneralfeedback, $when);
1959          $options->rightanswer = self::extract($quiz->reviewrightanswer, $when);
1960          $options->overallfeedback = self::extract($quiz->reviewoverallfeedback, $when);
1961  
1962          $options->numpartscorrect = $options->feedback;
1963          $options->manualcomment = $options->feedback;
1964  
1965          if ($quiz->questiondecimalpoints != -1) {
1966              $options->markdp = $quiz->questiondecimalpoints;
1967          } else {
1968              $options->markdp = $quiz->decimalpoints;
1969          }
1970  
1971          return $options;
1972      }
1973  
1974      protected static function extract($bitmask, $bit,
1975              $whenset = self::VISIBLE, $whennotset = self::HIDDEN) {
1976          if ($bitmask & $bit) {
1977              return $whenset;
1978          } else {
1979              return $whennotset;
1980          }
1981      }
1982  }
1983  
1984  /**
1985   * A {@link qubaid_condition} for finding all the question usages belonging to
1986   * a particular quiz.
1987   *
1988   * @copyright  2010 The Open University
1989   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1990   */
1991  class qubaids_for_quiz extends qubaid_join {
1992      public function __construct($quizid, $includepreviews = true, $onlyfinished = false) {
1993          $where = 'quiza.quiz = :quizaquiz';
1994          $params = array('quizaquiz' => $quizid);
1995  
1996          if (!$includepreviews) {
1997              $where .= ' AND preview = 0';
1998          }
1999  
2000          if ($onlyfinished) {
2001              $where .= ' AND state = :statefinished';
2002              $params['statefinished'] = quiz_attempt::FINISHED;
2003          }
2004  
2005          parent::__construct('{quiz_attempts} quiza', 'quiza.uniqueid', $where, $params);
2006      }
2007  }
2008  
2009  /**
2010   * A {@link qubaid_condition} for finding all the question usages belonging to a particular user and quiz combination.
2011   *
2012   * @copyright  2018 Andrew Nicols <andrwe@nicols.co.uk>
2013   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
2014   */
2015  class qubaids_for_quiz_user extends qubaid_join {
2016      /**
2017       * Constructor for this qubaid.
2018       *
2019       * @param   int     $quizid The quiz to search.
2020       * @param   int     $userid The user to filter on
2021       * @param   bool    $includepreviews Whether to include preview attempts
2022       * @param   bool    $onlyfinished Whether to only include finished attempts or not
2023       */
2024      public function __construct($quizid, $userid, $includepreviews = true, $onlyfinished = false) {
2025          $where = 'quiza.quiz = :quizaquiz AND quiza.userid = :quizauserid';
2026          $params = [
2027              'quizaquiz' => $quizid,
2028              'quizauserid' => $userid,
2029          ];
2030  
2031          if (!$includepreviews) {
2032              $where .= ' AND preview = 0';
2033          }
2034  
2035          if ($onlyfinished) {
2036              $where .= ' AND state = :statefinished';
2037              $params['statefinished'] = quiz_attempt::FINISHED;
2038          }
2039  
2040          parent::__construct('{quiz_attempts} quiza', 'quiza.uniqueid', $where, $params);
2041      }
2042  }
2043  
2044  /**
2045   * Creates a textual representation of a question for display.
2046   *
2047   * @param object $question A question object from the database questions table
2048   * @param bool $showicon If true, show the question's icon with the question. False by default.
2049   * @param bool $showquestiontext If true (default), show question text after question name.
2050   *       If false, show only question name.
2051   * @param bool $showidnumber If true, show the question's idnumber, if any. False by default.
2052   * @param core_tag_tag[]|bool $showtags if array passed, show those tags. Else, if true, get and show tags,
2053   *       else, don't show tags (which is the default).
2054   * @return string HTML fragment.
2055   */
2056  function quiz_question_tostring($question, $showicon = false, $showquestiontext = true,
2057          $showidnumber = false, $showtags = false) {
2058      global $OUTPUT;
2059      $result = '';
2060  
2061      // Question name.
2062      $name = shorten_text(format_string($question->name), 200);
2063      if ($showicon) {
2064          $name .= print_question_icon($question) . ' ' . $name;
2065      }
2066      $result .= html_writer::span($name, 'questionname');
2067  
2068      // Question idnumber.
2069      if ($showidnumber && $question->idnumber !== null && $question->idnumber !== '') {
2070          $result .= ' ' . html_writer::span(
2071                  html_writer::span(get_string('idnumber', 'question'), 'accesshide') .
2072                  ' ' . s($question->idnumber), 'badge badge-primary');
2073      }
2074  
2075      // Question tags.
2076      if (is_array($showtags)) {
2077          $tags = $showtags;
2078      } else if ($showtags) {
2079          $tags = core_tag_tag::get_item_tags('core_question', 'question', $question->id);
2080      } else {
2081          $tags = [];
2082      }
2083      if ($tags) {
2084          $result .= $OUTPUT->tag_list($tags, null, 'd-inline', 0, null, true);
2085      }
2086  
2087      // Question text.
2088      if ($showquestiontext) {
2089          $questiontext = question_utils::to_plain_text($question->questiontext,
2090                  $question->questiontextformat, array('noclean' => true, 'para' => false));
2091          $questiontext = shorten_text($questiontext, 200);
2092          if ($questiontext) {
2093              $result .= ' ' . html_writer::span(s($questiontext), 'questiontext');
2094          }
2095      }
2096  
2097      return $result;
2098  }
2099  
2100  /**
2101   * Verify that the question exists, and the user has permission to use it.
2102   * Does not return. Throws an exception if the question cannot be used.
2103   * @param int $questionid The id of the question.
2104   */
2105  function quiz_require_question_use($questionid) {
2106      global $DB;
2107      $question = $DB->get_record('question', array('id' => $questionid), '*', MUST_EXIST);
2108      question_require_capability_on($question, 'use');
2109  }
2110  
2111  /**
2112   * Verify that the question exists, and the user has permission to use it.
2113   * @param object $quiz the quiz settings.
2114   * @param int $slot which question in the quiz to test.
2115   * @return bool whether the user can use this question.
2116   */
2117  function quiz_has_question_use($quiz, $slot) {
2118      global $DB;
2119      $question = $DB->get_record_sql("
2120              SELECT q.*
2121                FROM {quiz_slots} slot
2122                JOIN {question} q ON q.id = slot.questionid
2123               WHERE slot.quizid = ? AND slot.slot = ?", array($quiz->id, $slot));
2124      if (!$question) {
2125          return false;
2126      }
2127      return question_has_capability_on($question, 'use');
2128  }
2129  
2130  /**
2131   * Add a question to a quiz
2132   *
2133   * Adds a question to a quiz by updating $quiz as well as the
2134   * quiz and quiz_slots tables. It also adds a page break if required.
2135   * @param int $questionid The id of the question to be added
2136   * @param object $quiz The extended quiz object as used by edit.php
2137   *      This is updated by this function
2138   * @param int $page Which page in quiz to add the question on. If 0 (default),
2139   *      add at the end
2140   * @param float $maxmark The maximum mark to set for this question. (Optional,
2141   *      defaults to question.defaultmark.
2142   * @return bool false if the question was already in the quiz
2143   */
2144  function quiz_add_quiz_question($questionid, $quiz, $page = 0, $maxmark = null) {
2145      global $DB;
2146  
2147      // Make sue the question is not of the "random" type.
2148      $questiontype = $DB->get_field('question', 'qtype', array('id' => $questionid));
2149      if ($questiontype == 'random') {
2150          throw new coding_exception(
2151                  'Adding "random" questions via quiz_add_quiz_question() is deprecated. Please use quiz_add_random_questions().'
2152          );
2153      }
2154  
2155      $trans = $DB->start_delegated_transaction();
2156      $slots = $DB->get_records('quiz_slots', array('quizid' => $quiz->id),
2157              'slot', 'questionid, slot, page, id');
2158      if (array_key_exists($questionid, $slots)) {
2159          $trans->allow_commit();
2160          return false;
2161      }
2162  
2163      $maxpage = 1;
2164      $numonlastpage = 0;
2165      foreach ($slots as $slot) {
2166          if ($slot->page > $maxpage) {
2167              $maxpage = $slot->page;
2168              $numonlastpage = 1;
2169          } else {
2170              $numonlastpage += 1;
2171          }
2172      }
2173  
2174      // Add the new question instance.
2175      $slot = new stdClass();
2176      $slot->quizid = $quiz->id;
2177      $slot->questionid = $questionid;
2178  
2179      if ($maxmark !== null) {
2180          $slot->maxmark = $maxmark;
2181      } else {
2182          $slot->maxmark = $DB->get_field('question', 'defaultmark', array('id' => $questionid));
2183      }
2184  
2185      if (is_int($page) && $page >= 1) {
2186          // Adding on a given page.
2187          $lastslotbefore = 0;
2188          foreach (array_reverse($slots) as $otherslot) {
2189              if ($otherslot->page > $page) {
2190                  $DB->set_field('quiz_slots', 'slot', $otherslot->slot + 1, array('id' => $otherslot->id));
2191              } else {
2192                  $lastslotbefore = $otherslot->slot;
2193                  break;
2194              }
2195          }
2196          $slot->slot = $lastslotbefore + 1;
2197          $slot->page = min($page, $maxpage + 1);
2198  
2199          quiz_update_section_firstslots($quiz->id, 1, max($lastslotbefore, 1));
2200  
2201      } else {
2202          $lastslot = end($slots);
2203          if ($lastslot) {
2204              $slot->slot = $lastslot->slot + 1;
2205          } else {
2206              $slot->slot = 1;
2207          }
2208          if ($quiz->questionsperpage && $numonlastpage >= $quiz->questionsperpage) {
2209              $slot->page = $maxpage + 1;
2210          } else {
2211              $slot->page = $maxpage;
2212          }
2213      }
2214  
2215      $DB->insert_record('quiz_slots', $slot);
2216      $trans->allow_commit();
2217  }
2218  
2219  /**
2220   * Move all the section headings in a certain slot range by a certain offset.
2221   *
2222   * @param int $quizid the id of a quiz
2223   * @param int $direction amount to adjust section heading positions. Normally +1 or -1.
2224   * @param int $afterslot adjust headings that start after this slot.
2225   * @param int|null $beforeslot optionally, only adjust headings before this slot.
2226   */
2227  function quiz_update_section_firstslots($quizid, $direction, $afterslot, $beforeslot = null) {
2228      global $DB;
2229      $where = 'quizid = ? AND firstslot > ?';
2230      $params = [$direction, $quizid, $afterslot];
2231      if ($beforeslot) {
2232          $where .= ' AND firstslot < ?';
2233          $params[] = $beforeslot;
2234      }
2235      $firstslotschanges = $DB->get_records_select_menu('quiz_sections',
2236              $where, $params, '', 'firstslot, firstslot + ?');
2237      update_field_with_unique_index('quiz_sections', 'firstslot', $firstslotschanges, ['quizid' => $quizid]);
2238  }
2239  
2240  /**
2241   * Add a random question to the quiz at a given point.
2242   * @param stdClass $quiz the quiz settings.
2243   * @param int $addonpage the page on which to add the question.
2244   * @param int $categoryid the question category to add the question from.
2245   * @param int $number the number of random questions to add.
2246   * @param bool $includesubcategories whether to include questoins from subcategories.
2247   * @param int[] $tagids Array of tagids. The question that will be picked randomly should be tagged with all these tags.
2248   */
2249  function quiz_add_random_questions($quiz, $addonpage, $categoryid, $number,
2250          $includesubcategories, $tagids = []) {
2251      global $DB;
2252  
2253      $category = $DB->get_record('question_categories', array('id' => $categoryid));
2254      if (!$category) {
2255          print_error('invalidcategoryid', 'error');
2256      }
2257  
2258      $catcontext = context::instance_by_id($category->contextid);
2259      require_capability('moodle/question:useall', $catcontext);
2260  
2261      $tags = \core_tag_tag::get_bulk($tagids, 'id, name');
2262      $tagstrings = [];
2263      foreach ($tags as $tag) {
2264          $tagstrings[] = "{$tag->id},{$tag->name}";
2265      }
2266  
2267      // Find existing random questions in this category that are
2268      // not used by any quiz.
2269      $existingquestions = $DB->get_records_sql(
2270          "SELECT q.id, q.qtype FROM {question} q
2271          WHERE qtype = 'random'
2272              AND category = ?
2273              AND " . $DB->sql_compare_text('questiontext') . " = ?
2274              AND NOT EXISTS (
2275                      SELECT *
2276                        FROM {quiz_slots}
2277                       WHERE questionid = q.id)
2278          ORDER BY id", array($category->id, $includesubcategories ? '1' : '0'));
2279  
2280      for ($i = 0; $i < $number; $i++) {
2281          // Take as many of orphaned "random" questions as needed.
2282          if (!$question = array_shift($existingquestions)) {
2283              $form = new stdClass();
2284              $form->category = $category->id . ',' . $category->contextid;
2285              $form->includesubcategories = $includesubcategories;
2286              $form->fromtags = $tagstrings;
2287              $form->defaultmark = 1;
2288              $form->hidden = 1;
2289              $form->stamp = make_unique_id_code(); // Set the unique code (not to be changed).
2290              $question = new stdClass();
2291              $question->qtype = 'random';
2292              $question = question_bank::get_qtype('random')->save_question($question, $form);
2293              if (!isset($question->id)) {
2294                  print_error('cannotinsertrandomquestion', 'quiz');
2295              }
2296          }
2297  
2298          $randomslotdata = new stdClass();
2299          $randomslotdata->quizid = $quiz->id;
2300          $randomslotdata->questionid = $question->id;
2301          $randomslotdata->questioncategoryid = $categoryid;
2302          $randomslotdata->includingsubcategories = $includesubcategories ? 1 : 0;
2303          $randomslotdata->maxmark = 1;
2304  
2305          $randomslot = new \mod_quiz\local\structure\slot_random($randomslotdata);
2306          $randomslot->set_quiz($quiz);
2307          $randomslot->set_tags($tags);
2308          $randomslot->insert($addonpage);
2309      }
2310  }
2311  
2312  /**
2313   * Mark the activity completed (if required) and trigger the course_module_viewed event.
2314   *
2315   * @param  stdClass $quiz       quiz object
2316   * @param  stdClass $course     course object
2317   * @param  stdClass $cm         course module object
2318   * @param  stdClass $context    context object
2319   * @since Moodle 3.1
2320   */
2321  function quiz_view($quiz, $course, $cm, $context) {
2322  
2323      $params = array(
2324          'objectid' => $quiz->id,
2325          'context' => $context
2326      );
2327  
2328      $event = \mod_quiz\event\course_module_viewed::create($params);
2329      $event->add_record_snapshot('quiz', $quiz);
2330      $event->trigger();
2331  
2332      // Completion.
2333      $completion = new completion_info($course);
2334      $completion->set_module_viewed($cm);
2335  }
2336  
2337  /**
2338   * Validate permissions for creating a new attempt and start a new preview attempt if required.
2339   *
2340   * @param  quiz $quizobj quiz object
2341   * @param  quiz_access_manager $accessmanager quiz access manager
2342   * @param  bool $forcenew whether was required to start a new preview attempt
2343   * @param  int $page page to jump to in the attempt
2344   * @param  bool $redirect whether to redirect or throw exceptions (for web or ws usage)
2345   * @return array an array containing the attempt information, access error messages and the page to jump to in the attempt
2346   * @throws moodle_quiz_exception
2347   * @since Moodle 3.1
2348   */
2349  function quiz_validate_new_attempt(quiz $quizobj, quiz_access_manager $accessmanager, $forcenew, $page, $redirect) {
2350      global $DB, $USER;
2351      $timenow = time();
2352  
2353      if ($quizobj->is_preview_user() && $forcenew) {
2354          $accessmanager->current_attempt_finished();
2355      }
2356  
2357      // Check capabilities.
2358      if (!$quizobj->is_preview_user()) {
2359          $quizobj->require_capability('mod/quiz:attempt');
2360      }
2361  
2362      // Check to see if a new preview was requested.
2363      if ($quizobj->is_preview_user() && $forcenew) {
2364          // To force the creation of a new preview, we mark the current attempt (if any)
2365          // as abandoned. It will then automatically be deleted below.
2366          $DB->set_field('quiz_attempts', 'state', quiz_attempt::ABANDONED,
2367                  array('quiz' => $quizobj->get_quizid(), 'userid' => $USER->id));
2368      }
2369  
2370      // Look for an existing attempt.
2371      $attempts = quiz_get_user_attempts($quizobj->get_quizid(), $USER->id, 'all', true);
2372      $lastattempt = end($attempts);
2373  
2374      $attemptnumber = null;
2375      // If an in-progress attempt exists, check password then redirect to it.
2376      if ($lastattempt && ($lastattempt->state == quiz_attempt::IN_PROGRESS ||
2377              $lastattempt->state == quiz_attempt::OVERDUE)) {
2378          $currentattemptid = $lastattempt->id;
2379          $messages = $accessmanager->prevent_access();
2380  
2381          // If the attempt is now overdue, deal with that.
2382          $quizobj->create_attempt_object($lastattempt)->handle_if_time_expired($timenow, true);
2383  
2384          // And, if the attempt is now no longer in progress, redirect to the appropriate place.
2385          if ($lastattempt->state == quiz_attempt::ABANDONED || $lastattempt->state == quiz_attempt::FINISHED) {
2386              if ($redirect) {
2387                  redirect($quizobj->review_url($lastattempt->id));
2388              } else {
2389                  throw new moodle_quiz_exception($quizobj, 'attemptalreadyclosed');
2390              }
2391          }
2392  
2393          // If the page number was not explicitly in the URL, go to the current page.
2394          if ($page == -1) {
2395              $page = $lastattempt->currentpage;
2396          }
2397  
2398      } else {
2399          while ($lastattempt && $lastattempt->preview) {
2400              $lastattempt = array_pop($attempts);
2401          }
2402  
2403          // Get number for the next or unfinished attempt.
2404          if ($lastattempt) {
2405              $attemptnumber = $lastattempt->attempt + 1;
2406          } else {
2407              $lastattempt = false;
2408              $attemptnumber = 1;
2409          }
2410          $currentattemptid = null;
2411  
2412          $messages = $accessmanager->prevent_access() +
2413              $accessmanager->prevent_new_attempt(count($attempts), $lastattempt);
2414  
2415          if ($page == -1) {
2416              $page = 0;
2417          }
2418      }
2419      return array($currentattemptid, $attemptnumber, $lastattempt, $messages, $page);
2420  }
2421  
2422  /**
2423   * Prepare and start a new attempt deleting the previous preview attempts.
2424   *
2425   * @param quiz $quizobj quiz object
2426   * @param int $attemptnumber the attempt number
2427   * @param object $lastattempt last attempt object
2428   * @param bool $offlineattempt whether is an offline attempt or not
2429   * @param array $forcedrandomquestions slot number => question id. Used for random questions,
2430   *      to force the choice of a particular actual question. Intended for testing purposes only.
2431   * @param array $forcedvariants slot number => variant. Used for questions with variants,
2432   *      to force the choice of a particular variant. Intended for testing purposes only.
2433   * @param int $userid Specific user id to create an attempt for that user, null for current logged in user
2434   * @return object the new attempt
2435   * @since  Moodle 3.1
2436   */
2437  function quiz_prepare_and_start_new_attempt(quiz $quizobj, $attemptnumber, $lastattempt,
2438          $offlineattempt = false, $forcedrandomquestions = [], $forcedvariants = [], $userid = null) {
2439      global $DB, $USER;
2440  
2441      if ($userid === null) {
2442          $userid = $USER->id;
2443          $ispreviewuser = $quizobj->is_preview_user();
2444      } else {
2445          $ispreviewuser = has_capability('mod/quiz:preview', $quizobj->get_context(), $userid);
2446      }
2447      // Delete any previous preview attempts belonging to this user.
2448      quiz_delete_previews($quizobj->get_quiz(), $userid);
2449  
2450      $quba = question_engine::make_questions_usage_by_activity('mod_quiz', $quizobj->get_context());
2451      $quba->set_preferred_behaviour($quizobj->get_quiz()->preferredbehaviour);
2452  
2453      // Create the new attempt and initialize the question sessions
2454      $timenow = time(); // Update time now, in case the server is running really slowly.
2455      $attempt = quiz_create_attempt($quizobj, $attemptnumber, $lastattempt, $timenow, $ispreviewuser, $userid);
2456  
2457      if (!($quizobj->get_quiz()->attemptonlast && $lastattempt)) {
2458          $attempt = quiz_start_new_attempt($quizobj, $quba, $attempt, $attemptnumber, $timenow,
2459                  $forcedrandomquestions, $forcedvariants);
2460      } else {
2461          $attempt = quiz_start_attempt_built_on_last($quba, $attempt, $lastattempt);
2462      }
2463  
2464      $transaction = $DB->start_delegated_transaction();
2465  
2466      // Init the timemodifiedoffline for offline attempts.
2467      if ($offlineattempt) {
2468          $attempt->timemodifiedoffline = $attempt->timemodified;
2469      }
2470      $attempt = quiz_attempt_save_started($quizobj, $quba, $attempt);
2471  
2472      $transaction->allow_commit();
2473  
2474      return $attempt;
2475  }
2476  
2477  /**
2478   * Check if the given calendar_event is either a user or group override
2479   * event for quiz.
2480   *
2481   * @param calendar_event $event The calendar event to check
2482   * @return bool
2483   */
2484  function quiz_is_overriden_calendar_event(\calendar_event $event) {
2485      global $DB;
2486  
2487      if (!isset($event->modulename)) {
2488          return false;
2489      }
2490  
2491      if ($event->modulename != 'quiz') {
2492          return false;
2493      }
2494  
2495      if (!isset($event->instance)) {
2496          return false;
2497      }
2498  
2499      if (!isset($event->userid) && !isset($event->groupid)) {
2500          return false;
2501      }
2502  
2503      $overrideparams = [
2504          'quiz' => $event->instance
2505      ];
2506  
2507      if (isset($event->groupid)) {
2508          $overrideparams['groupid'] = $event->groupid;
2509      } else if (isset($event->userid)) {
2510          $overrideparams['userid'] = $event->userid;
2511      }
2512  
2513      return $DB->record_exists('quiz_overrides', $overrideparams);
2514  }
2515  
2516  /**
2517   * Retrieves tag information for the given list of quiz slot ids.
2518   * Currently the only slots that have tags are random question slots.
2519   *
2520   * Example:
2521   * If we have 3 slots with id 1, 2, and 3. The first slot has two tags, the second
2522   * has one tag, and the third has zero tags. The return structure will look like:
2523   * [
2524   *      1 => [
2525   *          quiz_slot_tags.id => { ...tag data... },
2526   *          quiz_slot_tags.id => { ...tag data... },
2527   *      ],
2528   *      2 => [
2529   *          quiz_slot_tags.id => { ...tag data... },
2530   *      ],
2531   *      3 => [],
2532   * ]
2533   *
2534   * @param int[] $slotids The list of id for the quiz slots.
2535   * @return array[] List of quiz_slot_tags records indexed by slot id.
2536   */
2537  function quiz_retrieve_tags_for_slot_ids($slotids) {
2538      global $DB;
2539  
2540      if (empty($slotids)) {
2541          return [];
2542      }
2543  
2544      $slottags = $DB->get_records_list('quiz_slot_tags', 'slotid', $slotids);
2545      $tagsbyid = core_tag_tag::get_bulk(array_filter(array_column($slottags, 'tagid')), 'id, name');
2546      $tagsbyname = false; // It will be loaded later if required.
2547      $emptytagids = array_reduce($slotids, function($carry, $slotid) {
2548          $carry[$slotid] = [];
2549          return $carry;
2550      }, []);
2551  
2552      return array_reduce(
2553          $slottags,
2554          function($carry, $slottag) use ($slottags, $tagsbyid, $tagsbyname) {
2555              if (isset($tagsbyid[$slottag->tagid])) {
2556                  // Make sure that we're returning the most updated tag name.
2557                  $slottag->tagname = $tagsbyid[$slottag->tagid]->name;
2558              } else {
2559                  if ($tagsbyname === false) {
2560                      // We were hoping that this query could be avoided, but life
2561                      // showed its other side to us!
2562                      $tagcollid = core_tag_area::get_collection('core', 'question');
2563                      $tagsbyname = core_tag_tag::get_by_name_bulk(
2564                          $tagcollid,
2565                          array_column($slottags, 'tagname'),
2566                          'id, name'
2567                      );
2568                  }
2569                  if (isset($tagsbyname[$slottag->tagname])) {
2570                      // Make sure that we're returning the current tag id that matches
2571                      // the given tag name.
2572                      $slottag->tagid = $tagsbyname[$slottag->tagname]->id;
2573                  } else {
2574                      // The tag does not exist anymore (neither the tag id nor the tag name
2575                      // matches an existing tag).
2576                      // We still need to include this row in the result as some callers might
2577                      // be interested in these rows. An example is the editing forms that still
2578                      // need to display tag names even if they don't exist anymore.
2579                      $slottag->tagid = null;
2580                  }
2581              }
2582  
2583              $carry[$slottag->slotid][$slottag->id] = $slottag;
2584              return $carry;
2585          },
2586          $emptytagids
2587      );
2588  }
2589  
2590  /**
2591   * Retrieves tag information for the given quiz slot.
2592   * A quiz slot have some tags if and only if it is representing a random question by tags.
2593   *
2594   * @param int $slotid The id of the quiz slot.
2595   * @return stdClass[] List of quiz_slot_tags records.
2596   */
2597  function quiz_retrieve_slot_tags($slotid) {
2598      $slottags = quiz_retrieve_tags_for_slot_ids([$slotid]);
2599      return $slottags[$slotid];
2600  }
2601  
2602  /**
2603   * Retrieves tag ids for the given quiz slot.
2604   * A quiz slot have some tags if and only if it is representing a random question by tags.
2605   *
2606   * @param int $slotid The id of the quiz slot.
2607   * @return int[]
2608   */
2609  function quiz_retrieve_slot_tag_ids($slotid) {
2610      $tags = quiz_retrieve_slot_tags($slotid);
2611  
2612      // Only work with tags that exist.
2613      return array_filter(array_column($tags, 'tagid'));
2614  }
2615  
2616  /**
2617   * Get quiz attempt and handling error.
2618   *
2619   * @param int $attemptid the id of the current attempt.
2620   * @param int|null $cmid the course_module id for this quiz.
2621   * @return quiz_attempt $attemptobj all the data about the quiz attempt.
2622   * @throws moodle_exception
2623   */
2624  function quiz_create_attempt_handling_errors($attemptid, $cmid = null) {
2625      try {
2626          $attempobj = quiz_attempt::create($attemptid);
2627      } catch (moodle_exception $e) {
2628          if (!empty($cmid)) {
2629              list($course, $cm) = get_course_and_cm_from_cmid($cmid, 'quiz');
2630              $continuelink = new moodle_url('/mod/quiz/view.php', array('id' => $cmid));
2631              $context = context_module::instance($cm->id);
2632              if (has_capability('mod/quiz:preview', $context)) {
2633                  throw new moodle_exception('attempterrorcontentchange', 'quiz', $continuelink);
2634              } else {
2635                  throw new moodle_exception('attempterrorcontentchangeforuser', 'quiz', $continuelink);
2636              }
2637          } else {
2638              throw new moodle_exception('attempterrorinvalid', 'quiz');
2639          }
2640      }
2641      if (!empty($cmid) && $attempobj->get_cmid() != $cmid) {
2642          throw new moodle_exception('invalidcoursemodule');
2643      } else {
2644          return $attempobj;
2645      }
2646  }