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   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   * Code for handling and processing questions.
  19   *
  20   * This is code that is module independent, i.e., can be used by any module that
  21   * uses questions, like quiz, lesson, etc.
  22   * This script also loads the questiontype classes.
  23   * Code for handling the editing of questions is in question/editlib.php
  24   *
  25   * @package    core
  26   * @subpackage questionbank
  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  use core_question\local\bank\question_version_status;
  32  use core_question\question_reference_manager;
  33  
  34  defined('MOODLE_INTERNAL') || die();
  35  
  36  require_once($CFG->dirroot . '/question/engine/lib.php');
  37  require_once($CFG->dirroot . '/question/type/questiontypebase.php');
  38  
  39  
  40  
  41  // CONSTANTS.
  42  
  43  /**
  44   * Constant determines the number of answer boxes supplied in the editing
  45   * form for multiple choice and similar question types.
  46   */
  47  define("QUESTION_NUMANS", 10);
  48  
  49  /**
  50   * Constant determines the number of answer boxes supplied in the editing
  51   * form for multiple choice and similar question types to start with, with
  52   * the option of adding QUESTION_NUMANS_ADD more answers.
  53   */
  54  define("QUESTION_NUMANS_START", 3);
  55  
  56  /**
  57   * Constant determines the number of answer boxes to add in the editing
  58   * form for multiple choice and similar question types when the user presses
  59   * 'add form fields button'.
  60   */
  61  define("QUESTION_NUMANS_ADD", 3);
  62  
  63  /**
  64   * Move one question type in a list of question types. If you try to move one element
  65   * off of the end, nothing will change.
  66   *
  67   * @param array $sortedqtypes An array $qtype => anything.
  68   * @param string $tomove one of the keys from $sortedqtypes
  69   * @param integer $direction +1 or -1
  70   * @return array an array $index => $qtype, with $index from 0 to n in order, and
  71   *      the $qtypes in the same order as $sortedqtypes, except that $tomove will
  72   *      have been moved one place.
  73   */
  74  function question_reorder_qtypes($sortedqtypes, $tomove, $direction): array {
  75      $neworder = array_keys($sortedqtypes);
  76      // Find the element to move.
  77      $key = array_search($tomove, $neworder);
  78      if ($key === false) {
  79          return $neworder;
  80      }
  81      // Work out the other index.
  82      $otherkey = $key + $direction;
  83      if (!isset($neworder[$otherkey])) {
  84          return $neworder;
  85      }
  86      // Do the swap.
  87      $swap = $neworder[$otherkey];
  88      $neworder[$otherkey] = $neworder[$key];
  89      $neworder[$key] = $swap;
  90      return $neworder;
  91  }
  92  
  93  /**
  94   * Save a new question type order to the config_plugins table.
  95   *
  96   * @param array $neworder An arra $index => $qtype. Indices should start at 0 and be in order.
  97   * @param object $config get_config('question'), if you happen to have it around, to save one DB query.
  98   */
  99  function question_save_qtype_order($neworder, $config = null): void {
 100      if (is_null($config)) {
 101          $config = get_config('question');
 102      }
 103  
 104      foreach ($neworder as $index => $qtype) {
 105          $sortvar = $qtype . '_sortorder';
 106          if (!isset($config->$sortvar) || $config->$sortvar != $index + 1) {
 107              set_config($sortvar, $index + 1, 'question');
 108          }
 109      }
 110  }
 111  
 112  // FUNCTIONS.
 113  
 114  /**
 115   * Check if the question is used.
 116   *
 117   * @param array $questionids of question ids.
 118   * @return boolean whether any of these questions are being used by any part of Moodle.
 119   */
 120  function questions_in_use($questionids): bool {
 121  
 122      // Are they used by the core question system?
 123      if (question_engine::questions_in_use($questionids)) {
 124          return true;
 125      }
 126  
 127      if (question_reference_manager::questions_with_references($questionids)) {
 128          return true;
 129      }
 130  
 131      // Check if any plugins are using these questions.
 132      $callbacksbytype = get_plugins_with_function('questions_in_use');
 133      foreach ($callbacksbytype as $callbacks) {
 134          foreach ($callbacks as $function) {
 135              if ($function($questionids)) {
 136                  return true;
 137              }
 138          }
 139      }
 140  
 141      // Finally check legacy callback.
 142      $legacycallbacks = get_plugin_list_with_function('mod', 'question_list_instances');
 143      foreach ($legacycallbacks as $plugin => $function) {
 144          debugging($plugin . ' implements deprecated method ' . $function .
 145                  '. ' . $plugin . '_questions_in_use should be implemented instead.', DEBUG_DEVELOPER);
 146  
 147          if (isset($callbacksbytype['mod'][substr($plugin, 4)])) {
 148              continue; // Already done.
 149          }
 150  
 151          foreach ($questionids as $questionid) {
 152              if (!empty($function($questionid))) {
 153                  return true;
 154              }
 155          }
 156      }
 157  
 158      return false;
 159  }
 160  
 161  /**
 162   * Determine whether there are any questions belonging to this context, that is whether any of its
 163   * question categories contain any questions. This will return true even if all the questions are
 164   * hidden.
 165   *
 166   * @param mixed $context either a context object, or a context id.
 167   * @return boolean whether any of the question categories beloning to this context have
 168   *         any questions in them.
 169   */
 170  function question_context_has_any_questions($context): bool {
 171      global $DB;
 172      if (is_object($context)) {
 173          $contextid = $context->id;
 174      } else if (is_numeric($context)) {
 175          $contextid = $context;
 176      } else {
 177          throw new moodle_exception('invalidcontextinhasanyquestions', 'question');
 178      }
 179      $sql = 'SELECT qbe.*
 180                FROM {question_bank_entries} qbe
 181                JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid
 182               WHERE qc.contextid = ?';
 183      return $DB->record_exists_sql($sql, [$contextid]);
 184  }
 185  
 186  /**
 187   * Check whether a given grade is one of a list of allowed options. If not,
 188   * depending on $matchgrades, either return the nearest match, or return false
 189   * to signal an error.
 190   *
 191   * @param array $gradeoptionsfull list of valid options
 192   * @param int $grade grade to be tested
 193   * @param string $matchgrades 'error' or 'nearest'
 194   * @return false|int|string either 'fixed' value or false if error.
 195   */
 196  function match_grade_options($gradeoptionsfull, $grade, $matchgrades = 'error') {
 197  
 198      if ($matchgrades == 'error') {
 199          // ...(Almost) exact match, or an error.
 200          foreach ($gradeoptionsfull as $value => $option) {
 201              // Slightly fuzzy test, never check floats for equality.
 202              if (abs($grade - $value) < 0.00001) {
 203                  return $value; // Be sure the return the proper value.
 204              }
 205          }
 206          // Didn't find a match so that's an error.
 207          return false;
 208  
 209      } else if ($matchgrades == 'nearest') {
 210          // Work out nearest value.
 211          $best = false;
 212          $bestmismatch = 2;
 213          foreach ($gradeoptionsfull as $value => $option) {
 214              $newmismatch = abs($grade - $value);
 215              if ($newmismatch < $bestmismatch) {
 216                  $best = $value;
 217                  $bestmismatch = $newmismatch;
 218              }
 219          }
 220          return $best;
 221  
 222      } else {
 223          // Unknow option passed.
 224          throw new coding_exception('Unknown $matchgrades ' . $matchgrades .
 225                  ' passed to match_grade_options');
 226      }
 227  }
 228  
 229  /**
 230   * Category is about to be deleted,
 231   * 1/ All questions are deleted for this question category.
 232   * 2/ Any questions that can't be deleted are moved to a new category
 233   * NOTE: this function is called from lib/db/upgrade.php
 234   *
 235   * @param object|core_course_category $category course category object
 236   */
 237  function question_category_delete_safe($category): void {
 238      global $DB;
 239      $criteria = ['questioncategoryid' => $category->id];
 240      $context = context::instance_by_id($category->contextid, IGNORE_MISSING);
 241      $rescue = null; // See the code around the call to question_save_from_deletion.
 242  
 243      // Deal with any questions in the category.
 244      if ($questionentries = $DB->get_records('question_bank_entries', $criteria, '', 'id')) {
 245  
 246          foreach ($questionentries as $questionentry) {
 247              $questionids = $DB->get_records('question_versions',
 248                                                  ['questionbankentryid' => $questionentry->id], '', 'questionid');
 249  
 250              // Try to delete each question.
 251              foreach ($questionids as $questionid) {
 252                  question_delete_question($questionid->questionid, $category->contextid);
 253              }
 254          }
 255  
 256          // Check to see if there were any questions that were kept because
 257          // they are still in use somehow, even though quizzes in courses
 258          // in this category will already have been deleted. This could
 259          // happen, for example, if questions are added to a course,
 260          // and then that course is moved to another category (MDL-14802).
 261          $questionids = [];
 262          foreach ($questionentries as $questionentry) {
 263              $versions = $DB->get_records('question_versions', ['questionbankentryid' => $questionentry->id], '', 'questionid');
 264              foreach ($versions as $key => $version) {
 265                  $questionids[$key] = $version;
 266              }
 267          }
 268          if (!empty($questionids)) {
 269              $parentcontextid = SYSCONTEXTID;
 270              $name = get_string('unknown', 'question');
 271              if ($context !== false) {
 272                  $name = $context->get_context_name();
 273                  $parentcontext = $context->get_parent_context();
 274                  if ($parentcontext) {
 275                      $parentcontextid = $parentcontext->id;
 276                  }
 277              }
 278              question_save_from_deletion(array_keys($questionids), $parentcontextid, $name, $rescue);
 279          }
 280      }
 281  
 282      // Now delete the category.
 283      $DB->delete_records('question_categories', ['id' => $category->id]);
 284  }
 285  
 286  /**
 287   * Tests whether any question in a category is used by any part of Moodle.
 288   *
 289   * @param integer $categoryid a question category id.
 290   * @param boolean $recursive whether to check child categories too.
 291   * @return boolean whether any question in this category is in use.
 292   */
 293  function question_category_in_use($categoryid, $recursive = false): bool {
 294      global $DB;
 295  
 296      // Look at each question in the category.
 297      $questionids = question_bank::get_finder()->get_questions_from_categories([$categoryid], null);
 298      if ($questionids) {
 299          if (questions_in_use(array_keys($questionids))) {
 300              return true;
 301          }
 302      }
 303      if (!$recursive) {
 304          return false;
 305      }
 306  
 307      // Look under child categories recursively.
 308      if ($children = $DB->get_records('question_categories',
 309              ['parent' => $categoryid], '', 'id, 1')) {
 310          foreach ($children as $child) {
 311              if (question_category_in_use($child->id, $recursive)) {
 312                  return true;
 313              }
 314          }
 315      }
 316  
 317      return false;
 318  }
 319  
 320  /**
 321   * Check if there is more versions left for the entry.
 322   * If not delete the entry.
 323   *
 324   * @param int $entryid
 325   */
 326  function delete_question_bank_entry($entryid): void {
 327      global $DB;
 328      if (!$DB->record_exists('question_versions', ['questionbankentryid' => $entryid])) {
 329          $DB->delete_records('question_bank_entries', ['id' => $entryid]);
 330      }
 331  }
 332  
 333  /**
 334   * Deletes question and all associated data from the database
 335   *
 336   * It will not delete a question if it is used somewhere, instead it will just delete the reference.
 337   *
 338   * @param int $questionid The id of the question being deleted
 339   */
 340  function question_delete_question($questionid): void {
 341      global $DB;
 342  
 343      $question = $DB->get_record('question', ['id' => $questionid]);
 344      if (!$question) {
 345          // In some situations, for example if this was a child of a
 346          // Cloze question that was previously deleted, the question may already
 347          // have gone. In this case, just do nothing.
 348          return;
 349      }
 350  
 351      $sql = 'SELECT qv.id as versionid,
 352                     qv.version,
 353                     qbe.id as entryid,
 354                     qc.id as categoryid,
 355                     ctx.id as contextid
 356                FROM {question} q
 357                LEFT JOIN {question_versions} qv ON qv.questionid = q.id
 358                LEFT JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
 359                LEFT JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid
 360                LEFT JOIN {context} ctx ON ctx.id = qc.contextid
 361               WHERE q.id = ?';
 362      $questiondata = $DB->get_record_sql($sql, [$question->id]);
 363  
 364      $questionstocheck = [$question->id];
 365  
 366      if ($question->parent) {
 367          $questionstocheck[] = $question->parent;
 368      }
 369  
 370      // Do not delete a question if it is used by an activity module. Just mark the version hidden.
 371      if (questions_in_use($questionstocheck)) {
 372          $DB->set_field('question_versions', 'status',
 373                  question_version_status::QUESTION_STATUS_HIDDEN, ['questionid' => $questionid]);
 374          return;
 375      }
 376  
 377      // This sometimes happens in old sites with bad data.
 378      if (!$questiondata->contextid) {
 379          debugging('Deleting question ' . $question->id . ' which is no longer linked to a context. ' .
 380              'Assuming system context to avoid errors, but this may mean that some data like files, ' .
 381              'tags, are not cleaned up.');
 382          $questiondata->contextid = context_system::instance()->id;
 383          $questiondata->categoryid = 0;
 384      }
 385  
 386      // Delete previews of the question.
 387      $dm = new question_engine_data_mapper();
 388      $dm->delete_previews($question->id);
 389  
 390      // Delete questiontype-specific data.
 391      question_bank::get_qtype($question->qtype, false)->delete_question($question->id, $questiondata->contextid);
 392  
 393      // Now recursively delete all child questions
 394      if ($children = $DB->get_records('question',
 395              array('parent' => $questionid), '', 'id, qtype')) {
 396          foreach ($children as $child) {
 397              if ($child->id != $questionid) {
 398                  question_delete_question($child->id);
 399              }
 400          }
 401      }
 402  
 403      // Finally delete the question record itself.
 404      $DB->delete_records('question', ['id' => $question->id]);
 405      $DB->delete_records('question_versions', ['id' => $questiondata->versionid]);
 406      $DB->delete_records('question_references',
 407          [
 408              'version' => $questiondata->version,
 409              'questionbankentryid' => $questiondata->entryid,
 410          ]);
 411      delete_question_bank_entry($questiondata->entryid);
 412      question_bank::notify_question_edited($question->id);
 413  
 414      // Log the deletion of this question.
 415      // Any qbank plugins storing additional question data should observe this event and perform the necessary deletion.
 416      $question->category = $questiondata->categoryid;
 417      $question->contextid = $questiondata->contextid;
 418      $event = \core\event\question_deleted::create_from_question_instance($question);
 419      $event->add_record_snapshot('question', $question);
 420      $event->trigger();
 421  }
 422  
 423  /**
 424   * All question categories and their questions are deleted for this context id.
 425   *
 426   * @param int $contextid The contextid to delete question categories from
 427   * @return array only returns an empty array for backwards compatibility.
 428   */
 429  function question_delete_context($contextid): array {
 430      global $DB;
 431  
 432      $fields = 'id, parent, name, contextid';
 433      if ($categories = $DB->get_records('question_categories', ['contextid' => $contextid], 'parent', $fields)) {
 434          // Sort categories following their tree (parent-child) relationships this will make the feedback more readable.
 435          $categories = sort_categories_by_tree($categories);
 436          foreach ($categories as $category) {
 437              question_category_delete_safe($category);
 438          }
 439      }
 440      return [];
 441  }
 442  
 443  /**
 444   * All question categories and their questions are deleted for this course.
 445   *
 446   * @param stdClass $course an object representing the activity
 447   * @param bool $notused this argument is not used any more. Kept for backwards compatibility.
 448   * @return bool always true.
 449   */
 450  function question_delete_course($course, $notused = false): bool {
 451      $coursecontext = context_course::instance($course->id);
 452      question_delete_context($coursecontext->id);
 453      return true;
 454  }
 455  
 456  /**
 457   * Category is about to be deleted,
 458   * 1/ All question categories and their questions are deleted for this course category.
 459   * 2/ All questions are moved to new category
 460   *
 461   * @param stdClass|core_course_category $category course category object
 462   * @param stdClass|core_course_category $newcategory empty means everything deleted, otherwise id of
 463   *      category where content moved
 464   * @param bool $notused this argument is no longer used. Kept for backwards compatibility.
 465   * @return boolean
 466   */
 467  function question_delete_course_category($category, $newcategory, $notused=false): bool {
 468      global $DB;
 469  
 470      $context = context_coursecat::instance($category->id);
 471      if (empty($newcategory)) {
 472          question_delete_context($context->id);
 473  
 474      } else {
 475          // Move question categories to the new context.
 476          if (!$newcontext = context_coursecat::instance($newcategory->id)) {
 477              return false;
 478          }
 479  
 480          // Only move question categories if there is any question category at all!
 481          if ($topcategory = question_get_top_category($context->id)) {
 482              $newtopcategory = question_get_top_category($newcontext->id, true);
 483  
 484              question_move_category_to_context($topcategory->id, $context->id, $newcontext->id);
 485              $DB->set_field('question_categories', 'parent', $newtopcategory->id, ['parent' => $topcategory->id]);
 486              // Now delete the top category.
 487              $DB->delete_records('question_categories', ['id' => $topcategory->id]);
 488          }
 489      }
 490  
 491      return true;
 492  }
 493  
 494  /**
 495   * Creates a new category to save the questions in use.
 496   *
 497   * @param array $questionids of question ids
 498   * @param object $newcontextid the context to create the saved category in.
 499   * @param string $oldplace a textual description of the think being deleted,
 500   *      e.g. from get_context_name
 501   * @param object $newcategory
 502   * @return mixed false on
 503   */
 504  function question_save_from_deletion($questionids, $newcontextid, $oldplace, $newcategory = null) {
 505      global $DB;
 506  
 507      // Make a category in the parent context to move the questions to.
 508      if (is_null($newcategory)) {
 509          $newcategory = new stdClass();
 510          $newcategory->parent = question_get_top_category($newcontextid, true)->id;
 511          $newcategory->contextid = $newcontextid;
 512          // Max length of column name in question_categories is 255.
 513          $newcategory->name = shorten_text(get_string('questionsrescuedfrom', 'question', $oldplace), 255);
 514          $newcategory->info = get_string('questionsrescuedfrominfo', 'question', $oldplace);
 515          $newcategory->sortorder = 999;
 516          $newcategory->stamp = make_unique_id_code();
 517          $newcategory->id = $DB->insert_record('question_categories', $newcategory);
 518      }
 519  
 520      // Move any remaining questions to the 'saved' category.
 521      if (!question_move_questions_to_category($questionids, $newcategory->id)) {
 522          return false;
 523      }
 524      return $newcategory;
 525  }
 526  
 527  /**
 528   * All question categories and their questions are deleted for this activity.
 529   *
 530   * @param object $cm the course module object representing the activity
 531   * @param bool $notused the argument is not used any more. Kept for backwards compatibility.
 532   * @return boolean
 533   */
 534  function question_delete_activity($cm, $notused = false): bool {
 535      $modcontext = context_module::instance($cm->id);
 536      question_delete_context($modcontext->id);
 537      return true;
 538  }
 539  
 540  /**
 541   * This function will handle moving all tag instances to a new context for a
 542   * given list of questions.
 543   *
 544   * Questions can be tagged in up to two contexts:
 545   * 1.) The context the question exists in.
 546   * 2.) The course context (if the question context is a higher context.
 547   *     E.g. course category context or system context.
 548   *
 549   * This means a question that exists in a higher context (e.g. course cat or
 550   * system context) may have multiple groups of tags in any number of child
 551   * course contexts.
 552   *
 553   * Questions in the course category context can be move "down" a context level
 554   * into one of their child course contexts or activity contexts which affects the
 555   * availability of that question in other courses / activities.
 556   *
 557   * In this case it makes the questions no longer available in the other course or
 558   * activity contexts so we need to make sure that the tag instances in those other
 559   * contexts are removed.
 560   *
 561   * @param stdClass[] $questions The list of question being moved (must include
 562   *                              the id and contextid)
 563   * @param context $newcontext The Moodle context the questions are being moved to
 564   */
 565  function question_move_question_tags_to_new_context(array $questions, context $newcontext): void {
 566      // If the questions are moving to a new course/activity context then we need to
 567      // find any existing tag instances from any unavailable course contexts and
 568      // delete them because they will no longer be applicable (we don't support
 569      // tagging questions across courses).
 570      $instancestodelete = [];
 571      $instancesfornewcontext = [];
 572      $newcontextparentids = $newcontext->get_parent_context_ids();
 573      $questionids = array_map(function($question) {
 574          return $question->id;
 575      }, $questions);
 576      $questionstagobjects = core_tag_tag::get_items_tags('core_question', 'question', $questionids);
 577  
 578      foreach ($questions as $question) {
 579          $tagobjects = $questionstagobjects[$question->id] ?? [];
 580  
 581          foreach ($tagobjects as $tagobject) {
 582              $tagid = $tagobject->taginstanceid;
 583              $tagcontextid = $tagobject->taginstancecontextid;
 584              $istaginnewcontext = $tagcontextid == $newcontext->id;
 585              $istaginquestioncontext = $tagcontextid == $question->contextid;
 586  
 587              if ($istaginnewcontext) {
 588                  // This tag instance is already in the correct context so we can
 589                  // ignore it.
 590                  continue;
 591              }
 592  
 593              if ($istaginquestioncontext) {
 594                  // This tag instance is in the question context so it needs to be
 595                  // updated.
 596                  $instancesfornewcontext[] = $tagid;
 597                  continue;
 598              }
 599  
 600              // These tag instances are in neither the new context nor the
 601              // question context so we need to determine what to do based on
 602              // the context they are in and the new question context.
 603              $tagcontext = context::instance_by_id($tagcontextid);
 604              $tagcoursecontext = $tagcontext->get_course_context(false);
 605              // The tag is in a course context if get_course_context() returns
 606              // itself.
 607              $istaginstancecontextcourse = !empty($tagcoursecontext)
 608                  && $tagcontext->id == $tagcoursecontext->id;
 609  
 610              if ($istaginstancecontextcourse) {
 611                  // If the tag instance is in a course context we need to add some
 612                  // special handling.
 613                  $tagcontextparentids = $tagcontext->get_parent_context_ids();
 614                  $isnewcontextaparent = in_array($newcontext->id, $tagcontextparentids);
 615                  $isnewcontextachild = in_array($tagcontext->id, $newcontextparentids);
 616  
 617                  if ($isnewcontextaparent) {
 618                      // If the tag instance is a course context tag and the new
 619                      // context is still a parent context to the tag context then
 620                      // we can leave this tag where it is.
 621                      continue;
 622                  } else if ($isnewcontextachild) {
 623                      // If the new context is a child context (e.g. activity) of this
 624                      // tag instance then we should move all of this tag instance
 625                      // down into the activity context along with the question.
 626                      $instancesfornewcontext[] = $tagid;
 627                  } else {
 628                      // If the tag is in a course context that is no longer a parent
 629                      // or child of the new context then this tag instance should be
 630                      // removed.
 631                      $instancestodelete[] = $tagid;
 632                  }
 633              } else {
 634                  // This is a catch all for any tag instances not in the question
 635                  // context or a course context. These tag instances should be
 636                  // updated to the new context id. This will clean up old invalid
 637                  // data.
 638                  $instancesfornewcontext[] = $tagid;
 639              }
 640          }
 641      }
 642  
 643      if (!empty($instancestodelete)) {
 644          // Delete any course context tags that may no longer be valid.
 645          core_tag_tag::delete_instances_by_id($instancestodelete);
 646      }
 647  
 648      if (!empty($instancesfornewcontext)) {
 649          // Update the tag instances to the new context id.
 650          core_tag_tag::change_instances_context($instancesfornewcontext, $newcontext);
 651      }
 652  }
 653  
 654  /**
 655   * Check if an idnumber exist in the category.
 656   *
 657   * @param int $questionidnumber
 658   * @param int $categoryid
 659   * @param int $limitfrom
 660   * @param int $limitnum
 661   * @return array
 662   */
 663  function idnumber_exist_in_question_category($questionidnumber, $categoryid, $limitfrom = 0, $limitnum = 1): array {
 664      global $DB;
 665      $response  = false;
 666      $record = [];
 667      // Check if the idnumber exist in the category.
 668      $sql = 'SELECT qbe.idnumber
 669                FROM {question_bank_entries} qbe
 670               WHERE qbe.idnumber LIKE ?
 671                 AND qbe.questioncategoryid = ?
 672            ORDER BY qbe.idnumber DESC';
 673      $questionrecord = $DB->record_exists_sql($sql, [$questionidnumber, $categoryid]);
 674      if ((string) $questionidnumber !== '' && $questionrecord) {
 675          $record = $DB->get_records_sql($sql, [$questionidnumber . '_%', $categoryid], 0, 1);
 676          $response  = true;
 677      }
 678  
 679      return [$response, $record];
 680  }
 681  
 682  /**
 683   * This function should be considered private to the question bank, it is called from
 684   * question/editlib.php question/contextmoveq.php and a few similar places to to the
 685   * work of actually moving questions and associated data. However, callers of this
 686   * function also have to do other work, which is why you should not call this method
 687   * directly from outside the questionbank.
 688   *
 689   * @param array $questionids of question ids.
 690   * @param integer $newcategoryid the id of the category to move to.
 691   * @return bool
 692   */
 693  function question_move_questions_to_category($questionids, $newcategoryid): bool {
 694      global $DB;
 695  
 696      $newcategorydata = $DB->get_record('question_categories', ['id' => $newcategoryid]);
 697      if (!$newcategorydata) {
 698          return false;
 699      }
 700      list($questionidcondition, $params) = $DB->get_in_or_equal($questionids);
 701  
 702      $sql = "SELECT qv.id as versionid,
 703                     qbe.id as entryid,
 704                     qc.id as category,
 705                     qc.contextid as contextid,
 706                     q.id,
 707                     q.qtype,
 708                     qbe.idnumber
 709                FROM {question} q
 710                JOIN {question_versions} qv ON qv.questionid = q.id
 711                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
 712                JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid
 713               WHERE q.id $questionidcondition
 714                     OR (q.parent <> 0 AND q.parent $questionidcondition)";
 715  
 716      // Also, we need to move children questions.
 717      $params = array_merge($params, $params);
 718      $questions = $DB->get_records_sql($sql, $params);
 719      foreach ($questions as $question) {
 720          if ($newcategorydata->contextid != $question->contextid) {
 721              question_bank::get_qtype($question->qtype)->move_files(
 722                      $question->id, $question->contextid, $newcategorydata->contextid);
 723          }
 724          // Check whether there could be a clash of idnumbers in the new category.
 725          list($idnumberclash, $rec) = idnumber_exist_in_question_category($question->idnumber, $newcategoryid);
 726          if ($idnumberclash) {
 727              $unique = 1;
 728              if (count($rec)) {
 729                  $rec = reset($rec);
 730                  $idnumber = $rec->idnumber;
 731                  if (strpos($idnumber, '_') !== false) {
 732                      $unique = substr($idnumber, strpos($idnumber, '_') + 1) + 1;
 733                  }
 734              }
 735              // For the move process, add a numerical increment to the idnumber. This means that if a question is
 736              // mistakenly moved then the idnumber will not be completely lost.
 737              $qbankentry = new stdClass();
 738              $qbankentry->id = $question->entryid;
 739              $qbankentry->idnumber = $question->idnumber . '_' . $unique;
 740              $DB->update_record('question_bank_entries', $qbankentry);
 741          }
 742  
 743          // Update the entry to the new category id.
 744          $entry = new stdClass();
 745          $entry->id = $question->entryid;
 746          $entry->questioncategoryid = $newcategorydata->id;
 747          $DB->update_record('question_bank_entries', $entry);
 748  
 749          // Log this question move.
 750          $event = \core\event\question_moved::create_from_question_instance($question, context::instance_by_id($question->contextid),
 751                  ['oldcategoryid' => $question->category, 'newcategoryid' => $newcategorydata->id]);
 752          $event->trigger();
 753      }
 754  
 755      $newcontext = context::instance_by_id($newcategorydata->contextid);
 756      question_move_question_tags_to_new_context($questions, $newcontext);
 757  
 758      // TODO Deal with datasets.
 759  
 760      // Purge these questions from the cache.
 761      foreach ($questions as $question) {
 762          question_bank::notify_question_edited($question->id);
 763      }
 764  
 765      return true;
 766  }
 767  
 768  /**
 769   * Update the questioncontextid field for all question_set_references records given a new context id
 770   *
 771   * @param int $oldcategoryid Old category to be moved.
 772   * @param int $newcatgoryid New category that will receive the questions.
 773   * @param int $oldcontextid Old context to be moved.
 774   * @param int $newcontextid New context that will receive the questions.
 775   * @param bool $delete If the action is delete.
 776   * @throws dml_exception
 777   */
 778  function move_question_set_references(int $oldcategoryid, int $newcatgoryid,
 779                                        int $oldcontextid, int $newcontextid, bool $delete = false): void {
 780      global $DB;
 781  
 782      if ($delete || $oldcontextid !== $newcontextid) {
 783          $setreferences = $DB->get_recordset('question_set_references', ['questionscontextid' => $oldcontextid]);
 784          foreach ($setreferences as $setreference) {
 785              $filter = json_decode($setreference->filtercondition);
 786              if (isset($filter->questioncategoryid)) {
 787                  if ((int)$filter->questioncategoryid === $oldcategoryid) {
 788                      $setreference->questionscontextid = $newcontextid;
 789                      if ($oldcategoryid !== $newcatgoryid) {
 790                          $filter->questioncategoryid = $newcatgoryid;
 791                          $setreference->filtercondition = json_encode($filter);
 792                      }
 793                      $DB->update_record('question_set_references', $setreference);
 794                  }
 795              }
 796          }
 797          $setreferences->close();
 798      }
 799  }
 800  
 801  /**
 802   * This function helps move a question cateogry to a new context by moving all
 803   * the files belonging to all the questions to the new context.
 804   * Also moves subcategories.
 805   * @param integer $categoryid the id of the category being moved.
 806   * @param integer $oldcontextid the old context id.
 807   * @param integer $newcontextid the new context id.
 808   */
 809  function question_move_category_to_context($categoryid, $oldcontextid, $newcontextid): void {
 810      global $DB;
 811  
 812      $questions = [];
 813      $sql = "SELECT q.id, q.qtype
 814                FROM {question} q
 815                JOIN {question_versions} qv ON qv.questionid = q.id
 816                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
 817               WHERE qbe.questioncategoryid = ?";
 818  
 819      $questionids = $DB->get_records_sql_menu($sql, [$categoryid]);
 820      foreach ($questionids as $questionid => $qtype) {
 821          question_bank::get_qtype($qtype)->move_files($questionid, $oldcontextid, $newcontextid);
 822          // Purge this question from the cache.
 823          question_bank::notify_question_edited($questionid);
 824  
 825          $questions[] = (object) [
 826              'id' => $questionid,
 827              'contextid' => $oldcontextid
 828          ];
 829      }
 830  
 831      $newcontext = context::instance_by_id($newcontextid);
 832      question_move_question_tags_to_new_context($questions, $newcontext);
 833  
 834      $subcatids = $DB->get_records_menu('question_categories', ['parent' => $categoryid], '', 'id,1');
 835      foreach ($subcatids as $subcatid => $notused) {
 836          $DB->set_field('question_categories', 'contextid', $newcontextid, ['id' => $subcatid]);
 837          question_move_category_to_context($subcatid, $oldcontextid, $newcontextid);
 838      }
 839  }
 840  
 841  /**
 842   * Given a list of ids, load the basic information about a set of questions from
 843   * the questions table. The $join and $extrafields arguments can be used together
 844   * to pull in extra data. See, for example, the usage in {@see \mod_quiz\quiz_attempt}, and
 845   * read the code below to see how the SQL is assembled. Throws exceptions on error.
 846   *
 847   * @param array $questionids array of question ids to load. If null, then all
 848   * questions matched by $join will be loaded.
 849   * @param string $extrafields extra SQL code to be added to the query.
 850   * @param string $join extra SQL code to be added to the query.
 851   * @param array $extraparams values for any placeholders in $join.
 852   * You must use named placeholders.
 853   * @param string $orderby what to order the results by. Optional, default is unspecified order.
 854   *
 855   * @return array partially complete question objects. You need to call get_question_options
 856   * on them before they can be properly used.
 857   */
 858  function question_preload_questions($questionids = null, $extrafields = '', $join = '', $extraparams = [], $orderby = ''): array {
 859      global $DB;
 860  
 861      if ($questionids === null) {
 862          $extracondition = '';
 863          $params = [];
 864      } else {
 865          if (empty($questionids)) {
 866              return [];
 867          }
 868  
 869          list($questionidcondition, $params) = $DB->get_in_or_equal($questionids, SQL_PARAMS_NAMED, 'qid0000');
 870          $extracondition = 'WHERE q.id ' . $questionidcondition;
 871      }
 872  
 873      if ($join) {
 874          $join = 'JOIN ' . $join;
 875      }
 876  
 877      if ($extrafields) {
 878          $extrafields = ', ' . $extrafields;
 879      }
 880  
 881      if ($orderby) {
 882          $orderby = 'ORDER BY ' . $orderby;
 883      }
 884  
 885      $sql = "SELECT q.*,
 886                     qc.id as category,
 887                     qv.status,
 888                     qv.id as versionid,
 889                     qv.version,
 890                     qv.questionbankentryid,
 891                     qc.contextid as contextid
 892                     {$extrafields}
 893                FROM {question} q
 894                JOIN {question_versions} qv
 895                  ON qv.questionid = q.id
 896                JOIN {question_bank_entries} qbe
 897                  ON qbe.id = qv.questionbankentryid
 898                JOIN {question_categories} qc
 899                  ON qc.id = qbe.questioncategoryid
 900                {$join}
 901                {$extracondition}
 902                {$orderby}";
 903  
 904      // Load the questions.
 905      $questions = $DB->get_records_sql($sql, $extraparams + $params);
 906      foreach ($questions as $question) {
 907          $question->_partiallyloaded = true;
 908      }
 909  
 910      return $questions;
 911  }
 912  
 913  /**
 914   * Load a set of questions, given a list of ids. The $join and $extrafields arguments can be used
 915   * together to pull in extra data. See, for example, the usage in mod/quiz/attempt.php, and
 916   * read the code below to see how the SQL is assembled. Throws exceptions on error.
 917   *
 918   * @param array $questionids array of question ids.
 919   * @param string $extrafields extra SQL code to be added to the query.
 920   * @param string $join extra SQL code to be added to the query.
 921   * @return array|string question objects.
 922   */
 923  function question_load_questions($questionids, $extrafields = '', $join = '') {
 924      $questions = question_preload_questions($questionids, $extrafields, $join);
 925  
 926      // Load the question type specific information.
 927      if (!get_question_options($questions)) {
 928          return get_string('questionloaderror', 'question');
 929      }
 930  
 931      return $questions;
 932  }
 933  
 934  /**
 935   * Private function to factor common code out of get_question_options().
 936   *
 937   * @param object $question the question to tidy.
 938   * @param stdClass $category The question_categories record for the given $question.
 939   * @param \core_tag_tag[]|null $tagobjects The tags for the given $question.
 940   * @param stdClass[]|null $filtercourses The courses to filter the course tags by.
 941   */
 942  function _tidy_question($question, $category, array $tagobjects = null, array $filtercourses = null): void {
 943      // Convert numeric fields to float. This prevents these being displayed as 1.0000000.
 944      $question->defaultmark += 0;
 945      $question->penalty += 0;
 946  
 947      // Indicate the question is now fully initialised.
 948      if (isset($question->_partiallyloaded)) {
 949          unset($question->_partiallyloaded);
 950      }
 951  
 952      $question->categoryobject = $category;
 953  
 954      // Add any tags we have been passed.
 955      if (!is_null($tagobjects)) {
 956          $categorycontext = context::instance_by_id($category->contextid);
 957          $sortedtagobjects = question_sort_tags($tagobjects, $categorycontext, $filtercourses);
 958          $question->coursetagobjects = $sortedtagobjects->coursetagobjects;
 959          $question->coursetags = $sortedtagobjects->coursetags;
 960          $question->tagobjects = $sortedtagobjects->tagobjects;
 961          $question->tags = $sortedtagobjects->tags;
 962      }
 963  
 964      // Load question-type specific fields.
 965      if (question_bank::is_qtype_installed($question->qtype)) {
 966          question_bank::get_qtype($question->qtype)->get_question_options($question);
 967      } else {
 968          $question->questiontext = html_writer::tag('p', get_string('warningmissingtype',
 969                  'qtype_missingtype')) . $question->questiontext;
 970      }
 971  }
 972  
 973  /**
 974   * Updates the question objects with question type specific
 975   * information by calling {@see get_question_options()}
 976   *
 977   * Can be called either with an array of question objects or with a single
 978   * question object.
 979   *
 980   * @param mixed $questions Either an array of question objects to be updated
 981   *         or just a single question object
 982   * @param bool $loadtags load the question tags from the tags table. Optional, default false.
 983   * @param stdClass[] $filtercourses The courses to filter the course tags by.
 984   * @return bool Indicates success or failure.
 985   */
 986  function get_question_options(&$questions, $loadtags = false, $filtercourses = null) {
 987      global $DB;
 988  
 989      $questionlist = is_array($questions) ? $questions : [$questions];
 990      $categoryids = [];
 991      $questionids = [];
 992  
 993      if (empty($questionlist)) {
 994          return true;
 995      }
 996  
 997      foreach ($questionlist as $question) {
 998          $questionids[] = $question->id;
 999          if (isset($question->category)) {
1000              $qcategoryid = $question->category;
1001          } else {
1002              $qcategoryid = get_question_bank_entry($question->id)->questioncategoryid;
1003              $question->questioncategoryid = $qcategoryid;
1004          }
1005  
1006          if (!in_array($qcategoryid, $categoryids)) {
1007              $categoryids[] = $qcategoryid;
1008          }
1009      }
1010  
1011      $categories = $DB->get_records_list('question_categories', 'id', $categoryids);
1012  
1013      if ($loadtags && core_tag_tag::is_enabled('core_question', 'question')) {
1014          $tagobjectsbyquestion = core_tag_tag::get_items_tags('core_question', 'question', $questionids);
1015      } else {
1016          $tagobjectsbyquestion = null;
1017      }
1018  
1019      foreach ($questionlist as $question) {
1020          if (is_null($tagobjectsbyquestion)) {
1021              $tagobjects = null;
1022          } else {
1023              $tagobjects = $tagobjectsbyquestion[$question->id];
1024          }
1025          $qcategoryid = $question->category ?? $question->questioncategoryid ??
1026              get_question_bank_entry($question->id)->questioncategoryid;
1027  
1028          _tidy_question($question, $categories[$qcategoryid], $tagobjects, $filtercourses);
1029      }
1030  
1031      return true;
1032  }
1033  
1034  /**
1035   * Sort question tags by course or normal tags.
1036   *
1037   * This function also search tag instances that may have a context id that don't match either a course or
1038   * question context and fix the data setting the correct context id.
1039   *
1040   * @param \core_tag_tag[] $tagobjects The tags for the given $question.
1041   * @param stdClass $categorycontext The question categories context.
1042   * @param stdClass[]|null $filtercourses The courses to filter the course tags by.
1043   * @return stdClass $sortedtagobjects Sorted tag objects.
1044   */
1045  function question_sort_tags($tagobjects, $categorycontext, $filtercourses = null): stdClass {
1046  
1047      // Questions can have two sets of tag instances. One set at the
1048      // course context level and another at the context the question
1049      // belongs to (e.g. course category, system etc).
1050      $sortedtagobjects = new stdClass();
1051      $sortedtagobjects->coursetagobjects = [];
1052      $sortedtagobjects->coursetags = [];
1053      $sortedtagobjects->tagobjects = [];
1054      $sortedtagobjects->tags = [];
1055      $taginstanceidstonormalise = [];
1056      $filtercoursecontextids = [];
1057      $hasfiltercourses = !empty($filtercourses);
1058  
1059      if ($hasfiltercourses) {
1060          // If we're being asked to filter the course tags by a set of courses
1061          // then get the context ids to filter below.
1062          $filtercoursecontextids = array_map(function($course) {
1063              $coursecontext = context_course::instance($course->id);
1064              return $coursecontext->id;
1065          }, $filtercourses);
1066      }
1067  
1068      foreach ($tagobjects as $tagobject) {
1069          $tagcontextid = $tagobject->taginstancecontextid;
1070          $tagcontext = context::instance_by_id($tagcontextid);
1071          $tagcoursecontext = $tagcontext->get_course_context(false);
1072          // This is a course tag if the tag context is a course context which
1073          // doesn't match the question's context. Any tag in the question context
1074          // is not considered a course tag, it belongs to the question.
1075          $iscoursetag = $tagcoursecontext
1076              && $tagcontext->id == $tagcoursecontext->id
1077              && $tagcontext->id != $categorycontext->id;
1078  
1079          if ($iscoursetag) {
1080              // Any tag instance in a course context level is considered a course tag.
1081              if (!$hasfiltercourses || in_array($tagcontextid, $filtercoursecontextids)) {
1082                  // Add the tag to the list of course tags if we aren't being
1083                  // asked to filter or if this tag is in the list of courses
1084                  // we're being asked to filter by.
1085                  $sortedtagobjects->coursetagobjects[] = $tagobject;
1086                  $sortedtagobjects->coursetags[$tagobject->id] = $tagobject->get_display_name();
1087              }
1088          } else {
1089              // All non course context level tag instances or tags in the question
1090              // context belong to the context that the question was created in.
1091              $sortedtagobjects->tagobjects[] = $tagobject;
1092              $sortedtagobjects->tags[$tagobject->id] = $tagobject->get_display_name();
1093  
1094              // Due to legacy tag implementations that don't force the recording
1095              // of a context id, some tag instances may have context ids that don't
1096              // match either a course context or the question context. In this case
1097              // we should take the opportunity to fix up the data and set the correct
1098              // context id.
1099              if ($tagcontext->id != $categorycontext->id) {
1100                  $taginstanceidstonormalise[] = $tagobject->taginstanceid;
1101                  // Update the object properties to reflect the DB update that will
1102                  // happen below.
1103                  $tagobject->taginstancecontextid = $categorycontext->id;
1104              }
1105          }
1106      }
1107  
1108      if (!empty($taginstanceidstonormalise)) {
1109          // If we found any tag instances with incorrect context id data then we can
1110          // correct those values now by setting them to the question context id.
1111          core_tag_tag::change_instances_context($taginstanceidstonormalise, $categorycontext);
1112      }
1113  
1114      return $sortedtagobjects;
1115  }
1116  
1117  /**
1118   * Print the icon for the question type
1119   *
1120   * @param object $question The question object for which the icon is required.
1121   *       Only $question->qtype is used.
1122   * @return string the HTML for the img tag.
1123   */
1124  function print_question_icon($question): string {
1125      global $PAGE;
1126  
1127      if (gettype($question->qtype) == 'object') {
1128          $qtype = $question->qtype->name();
1129      } else {
1130          // Assume string.
1131          $qtype = $question->qtype;
1132      }
1133  
1134      return $PAGE->get_renderer('question', 'bank')->qtype_icon($qtype);
1135  }
1136  
1137  // CATEGORY FUNCTIONS.
1138  
1139  /**
1140   * Returns the categories with their names ordered following parent-child relationships.
1141   * finally it tries to return pending categories (those being orphaned, whose parent is
1142   * incorrect) to avoid missing any category from original array.
1143   *
1144   * @param array $categories
1145   * @param int $id
1146   * @param int $level
1147   * @return array
1148   */
1149  function sort_categories_by_tree(&$categories, $id = 0, $level = 1): array {
1150      global $DB;
1151  
1152      $children = [];
1153      $keys = array_keys($categories);
1154  
1155      foreach ($keys as $key) {
1156          if (!isset($categories[$key]->processed) && $categories[$key]->parent == $id) {
1157              $children[$key] = $categories[$key];
1158              $categories[$key]->processed = true;
1159              $children = $children + sort_categories_by_tree(
1160                      $categories, $children[$key]->id, $level + 1);
1161          }
1162      }
1163      // If level = 1, we have finished, try to look for non processed categories (bad parent) and sort them too.
1164      if ($level == 1) {
1165          foreach ($keys as $key) {
1166              // If not processed and it's a good candidate to start (because its parent doesn't exist in the course).
1167              if (!isset($categories[$key]->processed) && !$DB->record_exists('question_categories',
1168                      array('contextid' => $categories[$key]->contextid,
1169                              'id' => $categories[$key]->parent))) {
1170                  $children[$key] = $categories[$key];
1171                  $categories[$key]->processed = true;
1172                  $children = $children + sort_categories_by_tree(
1173                          $categories, $children[$key]->id, $level + 1);
1174              }
1175          }
1176      }
1177      return $children;
1178  }
1179  
1180  /**
1181   * Get the default category for the context.
1182   *
1183   * @param integer $contextid a context id.
1184   * @return object|bool the default question category for that context, or false if none.
1185   */
1186  function question_get_default_category($contextid) {
1187      global $DB;
1188      $category = $DB->get_records_select('question_categories', 'contextid = ? AND parent <> 0',
1189                                          [$contextid], 'id', '*', 0, 1);
1190      if (!empty($category)) {
1191          return reset($category);
1192      } else {
1193          return false;
1194      }
1195  }
1196  
1197  /**
1198   * Gets the top category in the given context.
1199   * This function can optionally create the top category if it doesn't exist.
1200   *
1201   * @param int $contextid A context id.
1202   * @param bool $create Whether create a top category if it doesn't exist.
1203   * @return bool|stdClass The top question category for that context, or false if none.
1204   */
1205  function question_get_top_category($contextid, $create = false) {
1206      global $DB;
1207      $category = $DB->get_record('question_categories', ['contextid' => $contextid, 'parent' => 0]);
1208  
1209      if (!$category && $create) {
1210          // We need to make one.
1211          $category = new stdClass();
1212          $category->name = 'top'; // A non-real name for the top category. It will be localised at the display time.
1213          $category->info = '';
1214          $category->contextid = $contextid;
1215          $category->parent = 0;
1216          $category->sortorder = 0;
1217          $category->stamp = make_unique_id_code();
1218          $category->id = $DB->insert_record('question_categories', $category);
1219      }
1220  
1221      return $category;
1222  }
1223  
1224  /**
1225   * Gets the list of top categories in the given contexts in the array("categoryid,categorycontextid") format.
1226   *
1227   * @param array $contextids List of context ids
1228   * @return array
1229   */
1230  function question_get_top_categories_for_contexts($contextids): array {
1231      global $DB;
1232  
1233      $concatsql = $DB->sql_concat_join("','", ['id', 'contextid']);
1234      list($insql, $params) = $DB->get_in_or_equal($contextids);
1235      $sql = "SELECT $concatsql
1236                FROM {question_categories}
1237               WHERE contextid $insql
1238                 AND parent = 0";
1239  
1240      $topcategories = $DB->get_fieldset_sql($sql, $params);
1241  
1242      return $topcategories;
1243  }
1244  
1245  /**
1246   * Gets the default category in the most specific context.
1247   * If no categories exist yet then default ones are created in all contexts.
1248   *
1249   * @param array $contexts  The context objects for this context and all parent contexts.
1250   * @return object The default category - the category in the course context
1251   */
1252  function question_make_default_categories($contexts): object {
1253      global $DB;
1254      static $preferredlevels = array(
1255          CONTEXT_COURSE => 4,
1256          CONTEXT_MODULE => 3,
1257          CONTEXT_COURSECAT => 2,
1258          CONTEXT_SYSTEM => 1,
1259      );
1260  
1261      $toreturn = null;
1262      $preferredness = 0;
1263      // If it already exists, just return it.
1264      foreach ($contexts as $key => $context) {
1265          $topcategory = question_get_top_category($context->id, true);
1266          if (!$exists = $DB->record_exists("question_categories",
1267                  array('contextid' => $context->id, 'parent' => $topcategory->id))) {
1268              // Otherwise, we need to make one.
1269              $category = new stdClass();
1270              $contextname = $context->get_context_name(false, true);
1271              // Max length of name field is 255.
1272              $category->name = shorten_text(get_string('defaultfor', 'question', $contextname), 255);
1273              $category->info = get_string('defaultinfofor', 'question', $contextname);
1274              $category->contextid = $context->id;
1275              $category->parent = $topcategory->id;
1276              // By default, all categories get this number, and are sorted alphabetically.
1277              $category->sortorder = 999;
1278              $category->stamp = make_unique_id_code();
1279              $category->id = $DB->insert_record('question_categories', $category);
1280          } else {
1281              $category = question_get_default_category($context->id);
1282          }
1283          $thispreferredness = $preferredlevels[$context->contextlevel];
1284          if (has_any_capability(array('moodle/question:usemine', 'moodle/question:useall'), $context)) {
1285              $thispreferredness += 10;
1286          }
1287          if ($thispreferredness > $preferredness) {
1288              $toreturn = $category;
1289              $preferredness = $thispreferredness;
1290          }
1291      }
1292  
1293      if (!is_null($toreturn)) {
1294          $toreturn = clone($toreturn);
1295      }
1296      return $toreturn;
1297  }
1298  
1299  /**
1300   * Get the list of categories.
1301   *
1302   * @param int $categoryid
1303   * @return array of question category ids of the category and all subcategories.
1304   */
1305  function question_categorylist($categoryid): array {
1306      global $DB;
1307  
1308      // Final list of category IDs.
1309      $categorylist = array();
1310  
1311      // A list of category IDs to check for any sub-categories.
1312      $subcategories = array($categoryid);
1313  
1314      while ($subcategories) {
1315          foreach ($subcategories as $subcategory) {
1316              // If anything from the temporary list was added already, then we have a loop.
1317              if (isset($categorylist[$subcategory])) {
1318                  throw new coding_exception("Category id=$subcategory is already on the list - loop of categories detected.");
1319              }
1320              $categorylist[$subcategory] = $subcategory;
1321          }
1322  
1323          list ($in, $params) = $DB->get_in_or_equal($subcategories);
1324  
1325          $subcategories = $DB->get_records_select_menu('question_categories', "parent $in", $params,
1326                                                      null, 'id,id AS id2');
1327      }
1328  
1329      return $categorylist;
1330  }
1331  
1332  /**
1333   * Get all parent categories of a given question category in decending order.
1334   * @param int $categoryid for which you want to find the parents.
1335   * @return array of question category ids of all parents categories.
1336   */
1337  function question_categorylist_parents(int $categoryid): array {
1338      global $DB;
1339      $parent = $DB->get_field('question_categories', 'parent', array('id' => $categoryid));
1340      if (!$parent) {
1341          return [];
1342      }
1343      $categorylist = [$parent];
1344      $currentid = $parent;
1345      while ($currentid) {
1346          $currentid = $DB->get_field('question_categories', 'parent', array('id' => $currentid));
1347          if ($currentid) {
1348              $categorylist[] = $currentid;
1349          }
1350      }
1351      // Present the list in decending order (the top category at the top).
1352      $categorylist = array_reverse($categorylist);
1353      return $categorylist;
1354  }
1355  
1356  // Import/Export Functions.
1357  
1358  /**
1359   * Get list of available import or export formats
1360   * @param string $type 'import' if import list, otherwise export list assumed
1361   * @return array sorted list of import/export formats available
1362   */
1363  function get_import_export_formats($type): array {
1364      global $CFG;
1365      require_once($CFG->dirroot . '/question/format.php');
1366  
1367      $formatclasses = core_component::get_plugin_list_with_class('qformat', '', 'format.php');
1368  
1369      $fileformatname = array();
1370      foreach ($formatclasses as $component => $formatclass) {
1371  
1372          $format = new $formatclass();
1373          if ($type == 'import') {
1374              $provided = $format->provide_import();
1375          } else {
1376              $provided = $format->provide_export();
1377          }
1378  
1379          if ($provided) {
1380              list($notused, $fileformat) = explode('_', $component, 2);
1381              $fileformatnames[$fileformat] = get_string('pluginname', $component);
1382          }
1383      }
1384  
1385      core_collator::asort($fileformatnames);
1386      return $fileformatnames;
1387  }
1388  
1389  
1390  /**
1391   * Create a reasonable default file name for exporting questions from a particular
1392   * category.
1393   * @param object $course the course the questions are in.
1394   * @param object $category the question category.
1395   * @return string the filename.
1396   */
1397  function question_default_export_filename($course, $category): string {
1398      // We build a string that is an appropriate name (questions) from the lang pack,
1399      // then the corse shortname, then the question category name, then a timestamp.
1400  
1401      $base = clean_filename(get_string('exportfilename', 'question'));
1402  
1403      $dateformat = str_replace(' ', '_', get_string('exportnameformat', 'question'));
1404      $timestamp = clean_filename(userdate(time(), $dateformat, 99, false));
1405  
1406      $shortname = clean_filename($course->shortname);
1407      if ($shortname == '' || $shortname == '_' ) {
1408          $shortname = $course->id;
1409      }
1410  
1411      $categoryname = clean_filename(format_string($category->name));
1412  
1413      return "{$base}-{$shortname}-{$categoryname}-{$timestamp}";
1414  }
1415  
1416  /**
1417   * Check capability on category.
1418   *
1419   * @param int|stdClass|question_definition $questionorid object or id.
1420   *      If an object is passed, it should include ->contextid and ->createdby.
1421   * @param string $cap 'add', 'edit', 'view', 'use', 'move' or 'tag'.
1422   * @param int $notused no longer used.
1423   * @return bool this user has the capability $cap for this question $question?
1424   */
1425  function question_has_capability_on($questionorid, $cap, $notused = -1): bool {
1426      global $USER, $DB;
1427  
1428      if (is_numeric($questionorid)) {
1429          $questionid = (int)$questionorid;
1430      } else if (is_object($questionorid)) {
1431          // All we really need in this function is the contextid and author of the question.
1432          // We won't bother fetching other details of the question if these 2 fields are provided.
1433          if (isset($questionorid->contextid) && isset($questionorid->createdby)) {
1434              $question = $questionorid;
1435          } else if (!empty($questionorid->id)) {
1436              $questionid = $questionorid->id;
1437          }
1438      }
1439  
1440      // At this point, either $question or $questionid is expected to be set.
1441      if (isset($questionid)) {
1442          try {
1443              $question = question_bank::load_question_data($questionid);
1444          } catch (Exception $e) {
1445              // Let's log the exception for future debugging,
1446              // but not during Behat, or we can't test these cases.
1447              if (!defined('BEHAT_SITE_RUNNING')) {
1448                  debugging($e->getMessage(), DEBUG_NORMAL, $e->getTrace());
1449              }
1450  
1451              $sql = 'SELECT q.id,
1452                             q.createdby,
1453                             qc.contextid
1454                        FROM {question} q
1455                        JOIN {question_versions} qv
1456                          ON qv.questionid = q.id
1457                        JOIN {question_bank_entries} qbe
1458                          ON qbe.id = qv.questionbankentryid
1459                        JOIN {question_categories} qc
1460                          ON qc.id = qbe.questioncategoryid
1461                       WHERE q.id = :id';
1462  
1463              // Well, at least we tried. Seems that we really have to read from DB.
1464              $question = $DB->get_record_sql($sql, ['id' => $questionid]);
1465          }
1466      }
1467  
1468      if (!isset($question)) {
1469          throw new coding_exception('$questionorid parameter needs to be an integer or an object.');
1470      }
1471  
1472      $context = context::instance_by_id($question->contextid);
1473  
1474      // These are existing questions capabilities that are set per category.
1475      // Each of these has a 'mine' and 'all' version that is appended to the capability name.
1476      $capabilitieswithallandmine = ['edit' => 1, 'view' => 1, 'use' => 1, 'move' => 1, 'tag' => 1, 'comment' => 1];
1477  
1478      if (!isset($capabilitieswithallandmine[$cap])) {
1479          return has_capability('moodle/question:' . $cap, $context);
1480      } else {
1481          return has_capability('moodle/question:' . $cap . 'all', $context) ||
1482              ($question->createdby == $USER->id && has_capability('moodle/question:' . $cap . 'mine', $context));
1483      }
1484  }
1485  
1486  /**
1487   * Require capability on question.
1488   *
1489   * @param int|stdClass|question_definition $question object or id.
1490   *      If an object is passed, it should include ->contextid and ->createdby.
1491   * @param string $cap 'add', 'edit', 'view', 'use', 'move' or 'tag'.
1492   * @return bool true if the user has the capability. Throws exception if not.
1493   */
1494  function question_require_capability_on($question, $cap): bool {
1495      if (!question_has_capability_on($question, $cap)) {
1496          throw new moodle_exception('nopermissions', '', '', $cap);
1497      }
1498      return true;
1499  }
1500  
1501  /**
1502   * Gets the question edit url.
1503   *
1504   * @param object $context a context
1505   * @return string|bool A URL for editing questions in this context.
1506   */
1507  function question_edit_url($context) {
1508      global $CFG, $SITE;
1509      if (!has_any_capability(question_get_question_capabilities(), $context)) {
1510          return false;
1511      }
1512      $baseurl = $CFG->wwwroot . '/question/edit.php?';
1513      $defaultcategory = question_get_default_category($context->id);
1514      if ($defaultcategory) {
1515          $baseurl .= 'cat=' . $defaultcategory->id . ',' . $context->id . '&amp;';
1516      }
1517      switch ($context->contextlevel) {
1518          case CONTEXT_SYSTEM:
1519              return $baseurl . 'courseid=' . $SITE->id;
1520          case CONTEXT_COURSECAT:
1521              // This is nasty, becuase we can only edit questions in a course
1522              // context at the moment, so for now we just return false.
1523              return false;
1524          case CONTEXT_COURSE:
1525              return $baseurl . 'courseid=' . $context->instanceid;
1526          case CONTEXT_MODULE:
1527              return $baseurl . 'cmid=' . $context->instanceid;
1528      }
1529  
1530  }
1531  
1532  /**
1533   * Adds question bank setting links to the given navigation node if caps are met
1534   * and loads the navigation from the plugins.
1535   * Qbank plugins can extend the navigation_plugin_base and add their own navigation node,
1536   * this method will help to autoload those nodes in the question bank navigation.
1537   *
1538   * @param navigation_node $navigationnode The navigation node to add the question branch to
1539   * @param object $context
1540   * @param string $baseurl the url of the base where the api is implemented from
1541   * @return navigation_node Returns the question branch that was added
1542   */
1543  function question_extend_settings_navigation(navigation_node $navigationnode, $context, $baseurl = '/question/edit.php') {
1544      global $PAGE;
1545  
1546      if ($context->contextlevel == CONTEXT_COURSE) {
1547          $params = ['courseid' => $context->instanceid];
1548      } else if ($context->contextlevel == CONTEXT_MODULE) {
1549          $params = ['cmid' => $context->instanceid];
1550      } else {
1551          return;
1552      }
1553  
1554      if (($cat = $PAGE->url->param('cat')) && preg_match('~\d+,\d+~', $cat)) {
1555          $params['cat'] = $cat;
1556      }
1557  
1558      $questionnode = $navigationnode->add(get_string('questionbank', 'question'),
1559              new moodle_url($baseurl, $params), navigation_node::TYPE_CONTAINER, null, 'questionbank');
1560  
1561      $corenavigations = [
1562              'questions' => [
1563                      'title' => get_string('questions', 'question'),
1564                      'url' => new moodle_url($baseurl)
1565              ],
1566              'categories' => [],
1567              'import' => [],
1568              'export' => []
1569      ];
1570  
1571      $plugins = \core_component::get_plugin_list_with_class('qbank', 'plugin_feature', 'plugin_feature.php');
1572      foreach ($plugins as $componentname => $plugin) {
1573          $pluginentrypoint = new $plugin();
1574          $pluginentrypointobject = $pluginentrypoint->get_navigation_node();
1575          // Don't need the plugins without navigation node.
1576          if ($pluginentrypointobject === null) {
1577              unset($plugins[$componentname]);
1578              continue;
1579          }
1580          foreach ($corenavigations as $key => $corenavigation) {
1581              if ($pluginentrypointobject->get_navigation_key() === $key) {
1582                  unset($plugins[$componentname]);
1583                  if (!\core\plugininfo\qbank::is_plugin_enabled($componentname)) {
1584                      unset($corenavigations[$key]);
1585                      break;
1586                  }
1587                  $corenavigations[$key] = [
1588                      'title' => $pluginentrypointobject->get_navigation_title(),
1589                      'url'   => $pluginentrypointobject->get_navigation_url()
1590                  ];
1591              }
1592          }
1593      }
1594  
1595      // Mitigate the risk of regression.
1596      foreach ($corenavigations as $node => $corenavigation) {
1597          if (empty($corenavigation)) {
1598              unset($corenavigations[$node]);
1599          }
1600      }
1601  
1602      // Community/additional plugins have navigation node.
1603      $pluginnavigations = [];
1604      foreach ($plugins as $componentname => $plugin) {
1605          $pluginentrypoint = new $plugin();
1606          $pluginentrypointobject = $pluginentrypoint->get_navigation_node();
1607          // Don't need the plugins without navigation node.
1608          if ($pluginentrypointobject === null || !\core\plugininfo\qbank::is_plugin_enabled($componentname)) {
1609              unset($plugins[$componentname]);
1610              continue;
1611          }
1612          $pluginnavigations[$pluginentrypointobject->get_navigation_key()] = [
1613              'title' => $pluginentrypointobject->get_navigation_title(),
1614              'url'   => $pluginentrypointobject->get_navigation_url(),
1615              'capabilities' => $pluginentrypointobject->get_navigation_capabilities()
1616          ];
1617      }
1618  
1619      $contexts = new core_question\local\bank\question_edit_contexts($context);
1620      foreach ($corenavigations as $key => $corenavigation) {
1621          if ($contexts->have_one_edit_tab_cap($key)) {
1622              $questionnode->add($corenavigation['title'], new moodle_url(
1623                      $corenavigation['url'], $params), navigation_node::TYPE_SETTING, null, $key);
1624          }
1625      }
1626  
1627      foreach ($pluginnavigations as $key => $pluginnavigation) {
1628          if (is_array($pluginnavigation['capabilities'])) {
1629              if (!$contexts->have_one_cap($pluginnavigation['capabilities'])) {
1630                  continue;
1631              }
1632          }
1633          $questionnode->add($pluginnavigation['title'], new moodle_url(
1634                  $pluginnavigation['url'], $params), navigation_node::TYPE_SETTING, null, $key);
1635      }
1636  
1637      return $questionnode;
1638  }
1639  
1640  /**
1641   * Get the array of capabilities for question.
1642   *
1643   * @return array all the capabilities that relate to accessing particular questions.
1644   */
1645  function question_get_question_capabilities(): array {
1646      return [
1647          'moodle/question:add',
1648          'moodle/question:editmine',
1649          'moodle/question:editall',
1650          'moodle/question:viewmine',
1651          'moodle/question:viewall',
1652          'moodle/question:usemine',
1653          'moodle/question:useall',
1654          'moodle/question:movemine',
1655          'moodle/question:moveall',
1656          'moodle/question:tagmine',
1657          'moodle/question:tagall',
1658          'moodle/question:commentmine',
1659          'moodle/question:commentall',
1660      ];
1661  }
1662  
1663  /**
1664   * Get the question bank caps.
1665   *
1666   * @return array all the question bank capabilities.
1667   */
1668  function question_get_all_capabilities(): array {
1669      $caps = question_get_question_capabilities();
1670      $caps[] = 'moodle/question:managecategory';
1671      $caps[] = 'moodle/question:flag';
1672      return $caps;
1673  }
1674  
1675  /**
1676   * Helps call file_rewrite_pluginfile_urls with the right parameters.
1677   *
1678   * @package  core_question
1679   * @category files
1680   * @param string $text text being processed
1681   * @param string $file the php script used to serve files
1682   * @param int $contextid context ID
1683   * @param string $component component
1684   * @param string $filearea filearea
1685   * @param array $ids other IDs will be used to check file permission
1686   * @param int $itemid item ID
1687   * @param array $options options
1688   * @return string
1689   */
1690  function question_rewrite_question_urls($text, $file, $contextid, $component, $filearea,
1691                                          array $ids, $itemid, array $options=null): string {
1692  
1693      $idsstr = '';
1694      if (!empty($ids)) {
1695          $idsstr .= implode('/', $ids);
1696      }
1697      if ($itemid !== null) {
1698          $idsstr .= '/' . $itemid;
1699      }
1700      return file_rewrite_pluginfile_urls($text, $file, $contextid, $component,
1701              $filearea, $idsstr, $options);
1702  }
1703  
1704  /**
1705   * Rewrite the PLUGINFILE urls in part of the content of a question, for use when
1706   * viewing the question outside an attempt (for example, in the question bank
1707   * listing or in the quiz statistics report).
1708   *
1709   * @param string $text the question text.
1710   * @param int $questionid the question id.
1711   * @param int $filecontextid the context id of the question being displayed.
1712   * @param string $filecomponent the component that owns the file area.
1713   * @param string $filearea the file area name.
1714   * @param int|null $itemid the file's itemid
1715   * @param int $previewcontextid the context id where the preview is being displayed.
1716   * @param string $previewcomponent component responsible for displaying the preview.
1717   * @param array $options text and file options ('forcehttps'=>false)
1718   * @return string $questiontext with URLs rewritten.
1719   */
1720  function question_rewrite_question_preview_urls($text, $questionid, $filecontextid, $filecomponent, $filearea, $itemid,
1721                                                  $previewcontextid, $previewcomponent, $options = null): string {
1722  
1723      $path = "preview/$previewcontextid/$previewcomponent/$questionid";
1724      if ($itemid) {
1725          $path .= '/' . $itemid;
1726      }
1727  
1728      return file_rewrite_pluginfile_urls($text, 'pluginfile.php', $filecontextid,
1729              $filecomponent, $filearea, $path, $options);
1730  }
1731  
1732  /**
1733   * Called by pluginfile.php to serve files related to the 'question' core
1734   * component and for files belonging to qtypes.
1735   *
1736   * For files that relate to questions in a question_attempt, then we delegate to
1737   * a function in the component that owns the attempt (for example in the quiz,
1738   * or in core question preview) to get necessary inforation.
1739   *
1740   * (Note that, at the moment, all question file areas relate to questions in
1741   * attempts, so the If at the start of the last paragraph is always true.)
1742   *
1743   * Does not return, either calls send_file_not_found(); or serves the file.
1744   *
1745   * @category files
1746   * @param stdClass $course course settings object
1747   * @param stdClass $context context object
1748   * @param string $component the name of the component we are serving files for.
1749   * @param string $filearea the name of the file area.
1750   * @param array $args the remaining bits of the file path.
1751   * @param bool $forcedownload whether the user must be forced to download the file.
1752   * @param array $options additional options affecting the file serving
1753   * @return array|bool
1754   */
1755  function question_pluginfile($course, $context, $component, $filearea, $args, $forcedownload, $options = []) {
1756      global $DB, $CFG;
1757  
1758      // Special case, sending a question bank export.
1759      if ($filearea === 'export') {
1760          list($context, $course, $cm) = get_context_info_array($context->id);
1761          require_login($course, false, $cm);
1762  
1763          require_once($CFG->dirroot . '/question/editlib.php');
1764          $contexts = new core_question\local\bank\question_edit_contexts($context);
1765          // Check export capability.
1766          $contexts->require_one_edit_tab_cap('export');
1767          $categoryid = (int)array_shift($args);
1768          $format      = array_shift($args);
1769          $cattofile   = array_shift($args);
1770          $contexttofile = array_shift($args);
1771          $filename    = array_shift($args);
1772  
1773          // Load parent class for import/export.
1774          require_once($CFG->dirroot . '/question/format.php');
1775          require_once($CFG->dirroot . '/question/editlib.php');
1776          require_once($CFG->dirroot . '/question/format/' . $format . '/format.php');
1777  
1778          $classname = 'qformat_' . $format;
1779          if (!class_exists($classname)) {
1780              send_file_not_found();
1781          }
1782  
1783          $qformat = new $classname();
1784  
1785          if (!$category = $DB->get_record('question_categories', array('id' => $categoryid))) {
1786              send_file_not_found();
1787          }
1788  
1789          $qformat->setCategory($category);
1790          $qformat->setContexts($contexts->having_one_edit_tab_cap('export'));
1791          $qformat->setCourse($course);
1792  
1793          if ($cattofile == 'withcategories') {
1794              $qformat->setCattofile(true);
1795          } else {
1796              $qformat->setCattofile(false);
1797          }
1798  
1799          if ($contexttofile == 'withcontexts') {
1800              $qformat->setContexttofile(true);
1801          } else {
1802              $qformat->setContexttofile(false);
1803          }
1804  
1805          if (!$qformat->exportpreprocess()) {
1806              send_file_not_found();
1807              throw new moodle_exception('exporterror', 'question', $thispageurl->out());
1808          }
1809  
1810          // Export data to moodle file pool.
1811          if (!$content = $qformat->exportprocess()) {
1812              send_file_not_found();
1813          }
1814  
1815          send_file($content, $filename, 0, 0, true, true, $qformat->mime_type());
1816      }
1817  
1818      // Normal case, a file belonging to a question.
1819      $qubaidorpreview = array_shift($args);
1820  
1821      // Two sub-cases: 1. A question being previewed outside an attempt/usage.
1822      if ($qubaidorpreview === 'preview') {
1823          $previewcontextid = (int)array_shift($args);
1824          $previewcomponent = array_shift($args);
1825          $questionid = (int) array_shift($args);
1826          $previewcontext = context_helper::instance_by_id($previewcontextid);
1827  
1828          $result = component_callback($previewcomponent, 'question_preview_pluginfile', array(
1829                  $previewcontext, $questionid,
1830                  $context, $component, $filearea, $args,
1831                  $forcedownload, $options), 'callbackmissing');
1832  
1833          if ($result === 'callbackmissing') {
1834              throw new coding_exception("Component {$previewcomponent} does not define the callback " .
1835                      "{$previewcomponent}_question_preview_pluginfile callback. " .
1836                      "Which is required if you are using question_rewrite_question_preview_urls.", DEBUG_DEVELOPER);
1837          }
1838  
1839          send_file_not_found();
1840      }
1841  
1842      // 2. A question being attempted in the normal way.
1843      $qubaid = (int)$qubaidorpreview;
1844      $slot = (int)array_shift($args);
1845  
1846      $module = $DB->get_field('question_usages', 'component',
1847              array('id' => $qubaid));
1848      if (!$module) {
1849          send_file_not_found();
1850      }
1851  
1852      if ($module === 'core_question_preview') {
1853          return qbank_previewquestion\helper::question_preview_question_pluginfile($course, $context,
1854                  $component, $filearea, $qubaid, $slot, $args, $forcedownload, $options);
1855  
1856      } else {
1857          $dir = core_component::get_component_directory($module);
1858          if (!file_exists("$dir/lib.php")) {
1859              send_file_not_found();
1860          }
1861          include_once("$dir/lib.php");
1862  
1863          $filefunction = $module . '_question_pluginfile';
1864          if (function_exists($filefunction)) {
1865              $filefunction($course, $context, $component, $filearea, $qubaid, $slot,
1866                  $args, $forcedownload, $options);
1867          }
1868  
1869          // Okay, we're here so lets check for function without 'mod_'.
1870          if (strpos($module, 'mod_') === 0) {
1871              $filefunctionold  = substr($module, 4) . '_question_pluginfile';
1872              if (function_exists($filefunctionold)) {
1873                  $filefunctionold($course, $context, $component, $filearea, $qubaid, $slot,
1874                      $args, $forcedownload, $options);
1875              }
1876          }
1877  
1878          send_file_not_found();
1879      }
1880  }
1881  
1882  /**
1883   * Serve questiontext files in the question text when they are displayed in this report.
1884   *
1885   * @param context $previewcontext the context in which the preview is happening.
1886   * @param int $questionid the question id.
1887   * @param context $filecontext the file (question) context.
1888   * @param string $filecomponent the component the file belongs to.
1889   * @param string $filearea the file area.
1890   * @param array $args remaining file args.
1891   * @param bool $forcedownload
1892   * @param array $options additional options affecting the file serving.
1893   */
1894  function core_question_question_preview_pluginfile($previewcontext, $questionid, $filecontext, $filecomponent,
1895                                                      $filearea, $args, $forcedownload, $options = []): void {
1896      global $DB;
1897      $sql = 'SELECT q.*,
1898                     qc.contextid
1899                FROM {question} q
1900                JOIN {question_versions} qv
1901                  ON qv.questionid = q.id
1902                JOIN {question_bank_entries} qbe
1903                  ON qbe.id = qv.questionbankentryid
1904                JOIN {question_categories} qc
1905                  ON qc.id = qbe.questioncategoryid
1906               WHERE q.id = :id
1907                 AND qc.contextid = :contextid';
1908  
1909      // Verify that contextid matches the question.
1910      $question = $DB->get_record_sql($sql, ['id' => $questionid, 'contextid' => $filecontext->id], MUST_EXIST);
1911  
1912      // Check the capability.
1913      list($context, $course, $cm) = get_context_info_array($previewcontext->id);
1914      require_login($course, false, $cm);
1915  
1916      question_require_capability_on($question, 'use');
1917  
1918      $fs = get_file_storage();
1919      $relativepath = implode('/', $args);
1920      $fullpath = "/{$filecontext->id}/{$filecomponent}/{$filearea}/{$relativepath}";
1921      if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
1922          send_file_not_found();
1923      }
1924  
1925      send_stored_file($file, 0, 0, $forcedownload, $options);
1926  }
1927  
1928  /**
1929   * Return a list of page types
1930   * @param string $pagetype current page type
1931   * @param stdClass $parentcontext Block's parent context
1932   * @param stdClass $currentcontext Current context of block
1933   * @return array
1934   */
1935  function question_page_type_list($pagetype, $parentcontext, $currentcontext): array {
1936      global $CFG;
1937      $types = [
1938          'question-*' => get_string('page-question-x', 'question'),
1939          'question-edit' => get_string('page-question-edit', 'question'),
1940          'question-category' => get_string('page-question-category', 'question'),
1941          'question-export' => get_string('page-question-export', 'question'),
1942          'question-import' => get_string('page-question-import', 'question')
1943      ];
1944      if ($currentcontext->contextlevel == CONTEXT_COURSE) {
1945          require_once($CFG->dirroot . '/course/lib.php');
1946          return array_merge(course_page_type_list($pagetype, $parentcontext, $currentcontext), $types);
1947      } else {
1948          return $types;
1949      }
1950  }
1951  
1952  /**
1953   * Does an activity module use the question bank?
1954   *
1955   * @param string $modname The name of the module (without mod_ prefix).
1956   * @return bool true if the module uses questions.
1957   */
1958  function question_module_uses_questions($modname): bool {
1959      if (plugin_supports('mod', $modname, FEATURE_USES_QUESTIONS)) {
1960          return true;
1961      }
1962  
1963      $component = 'mod_'.$modname;
1964      if (component_callback_exists($component, 'question_pluginfile')) {
1965          debugging("{$component} uses questions but doesn't declare FEATURE_USES_QUESTIONS", DEBUG_DEVELOPER);
1966          return true;
1967      }
1968  
1969      return false;
1970  }
1971  
1972  /**
1973   * If $oldidnumber ends in some digits then return the next available idnumber of the same form.
1974   *
1975   * So idnum -> null (no digits at the end) idnum0099 -> idnum0100 (if that is unused,
1976   * else whichever of idnum0101, idnume0102, ... is unused. idnum9 -> idnum10.
1977   *
1978   * @param string|null $oldidnumber a question idnumber, or can be null.
1979   * @param int $categoryid a question category id.
1980   * @return string|null suggested new idnumber for a question in that category, or null if one cannot be found.
1981   */
1982  function core_question_find_next_unused_idnumber(?string $oldidnumber, int $categoryid): ?string {
1983      global $DB;
1984  
1985      // The the old idnumber is not of the right form, bail now.
1986      if ($oldidnumber === null || !preg_match('~\d+$~', $oldidnumber, $matches)) {
1987          return null;
1988      }
1989  
1990      // Find all used idnumbers in one DB query.
1991      $usedidnumbers = $DB->get_records_select_menu('question_bank_entries', 'questioncategoryid = ? AND idnumber IS NOT NULL',
1992              [$categoryid], '', 'idnumber, 1');
1993  
1994      // Find the next unused idnumber.
1995      $numberbit = 'X' . $matches[0]; // Need a string here so PHP does not do '0001' + 1 = 2.
1996      $stem = substr($oldidnumber, 0, -strlen($matches[0]));
1997      do {
1998  
1999          // If we have got to something9999, insert an extra digit before incrementing.
2000          if (preg_match('~^(.*[^0-9])(9+)$~', $numberbit, $matches)) {
2001              $numberbit = $matches[1] . '0' . $matches[2];
2002          }
2003          $numberbit++;
2004          $newidnumber = $stem . substr($numberbit, 1);
2005      } while (isset($usedidnumbers[$newidnumber]));
2006  
2007      return (string) $newidnumber;
2008  }
2009  
2010  /**
2011   * Get the question_bank_entry object given a question id.
2012   *
2013   * @param int $questionid Question id.
2014   * @return false|mixed
2015   * @throws dml_exception
2016   */
2017  function get_question_bank_entry(int $questionid): object {
2018      global $DB;
2019  
2020      $sql = "SELECT qbe.*
2021                FROM {question} q
2022                JOIN {question_versions} qv ON qv.questionid = q.id
2023                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
2024               WHERE q.id = :id";
2025  
2026      $qbankentry = $DB->get_record_sql($sql, ['id' => $questionid]);
2027  
2028      return $qbankentry;
2029  }
2030  
2031  /**
2032   * Get the question versions given a question id in a descending sort .
2033   *
2034   * @param int $questionid Question id.
2035   * @return array
2036   * @throws dml_exception
2037   */
2038  function get_question_version($questionid): array {
2039      global $DB;
2040  
2041      $version = $DB->get_records('question_versions', ['questionid' => $questionid]);
2042      krsort($version);
2043  
2044      return $version;
2045  }
2046  
2047  /**
2048   * Get the next version number to create base on a Question bank entry id.
2049   *
2050   * @param int $questionbankentryid Question bank entry id.
2051   * @return int next version number.
2052   * @throws dml_exception
2053   */
2054  function get_next_version(int $questionbankentryid): int {
2055      global $DB;
2056  
2057      $sql = "SELECT MAX(qv.version)
2058                FROM {question_versions} qv
2059                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
2060               WHERE qbe.id = :id";
2061  
2062      $nextversion = $DB->get_field_sql($sql, ['id' => $questionbankentryid]);
2063  
2064      if ($nextversion) {
2065          return (int)$nextversion + 1;
2066      }
2067  
2068      return 1;
2069  }
2070  
2071  /**
2072   * Checks if question is the latest version.
2073   *
2074   * @param string $version Question version to check.
2075   * @param string $questionbankentryid Entry to check against.
2076   * @return bool
2077   */
2078  function is_latest(string $version, string $questionbankentryid) : bool {
2079      global $DB;
2080  
2081      $sql = 'SELECT MAX(version) AS max
2082                    FROM {question_versions}
2083                   WHERE questionbankentryid = ?';
2084      $latestversion = $DB->get_record_sql($sql, [$questionbankentryid]);
2085  
2086      if (isset($latestversion->max)) {
2087          return ($version === $latestversion->max) ? true : false;
2088      }
2089      return false;
2090  }
2091  
2092  // Deprecated functions from Moodle 4.0.
2093  
2094  /**
2095   * Generate the URL for starting a new preview of a given question with the given options.
2096   * @param integer $questionid the question to preview.
2097   * @param string $preferredbehaviour the behaviour to use for the preview.
2098   * @param float $maxmark the maximum to mark the question out of.
2099   * @param question_display_options $displayoptions the display options to use.
2100   * @param int $variant the variant of the question to preview. If null, one will
2101   *      be picked randomly.
2102   * @param object $context context to run the preview in (affects things like
2103   *      filter settings, theme, lang, etc.) Defaults to $PAGE->context.
2104   * @return moodle_url the URL.
2105   * @deprecated since Moodle 4.0
2106   * @see qbank_previewquestion\helper::question_preview_url()
2107   * @todo Final deprecation on Moodle 4.4 MDL-72438
2108   */
2109  function question_preview_url($questionid, $preferredbehaviour = null,
2110                                $maxmark = null, $displayoptions = null, $variant = null, $context = null) {
2111      debugging('Function question_preview_url() has been deprecated and moved to qbank_previewquestion plugin,
2112      Please use qbank_previewquestion\previewquestion_helper::question_preview_url() instead.', DEBUG_DEVELOPER);
2113  
2114      return \qbank_previewquestion\helper::question_preview_url($questionid, $preferredbehaviour,
2115          $maxmark, $displayoptions, $variant, $context);
2116  }
2117  
2118  /**
2119   * Popup params for the question preview.
2120   *
2121   * @return array that can be passed as $params to the {@see popup_action()} constructor.
2122   * @deprecated since Moodle 4.0
2123   * @see qbank_previewquestion\previewquestion_helper::question_preview_popup_params()
2124   * @todo Final deprecation on Moodle 4.4 MDL-72438
2125   */
2126  function question_preview_popup_params() {
2127      debugging('Function question_preview_popup_params() has been deprecated and moved to qbank_previewquestion plugin,
2128      Please use qbank_previewquestion\previewquestion_helper::question_preview_popup_params() instead.', DEBUG_DEVELOPER);
2129  
2130      return \qbank_previewquestion\helper::question_preview_popup_params();
2131  }
2132  
2133  /**
2134   * Creates a stamp that uniquely identifies this version of the question
2135   *
2136   * In future we want this to use a hash of the question data to guarantee that
2137   * identical versions have the same version stamp.
2138   *
2139   * @param object $question
2140   * @return string A unique version stamp
2141   * @deprecated since Moodle 4.0
2142   * @todo Final deprecation on Moodle 4.4 MDL-72438
2143   */
2144  function question_hash($question) {
2145      debugging('Function question_hash() has been deprecated without replacement.', DEBUG_DEVELOPER);
2146      return make_unique_id_code();
2147  }
2148  
2149  /**
2150   * Create url for question export.
2151   *
2152   * @param int $contextid
2153   * @param int $categoryid
2154   * @param string $format
2155   * @param string $withcategories
2156   * @param string $withcontexts
2157   * @param string $filename
2158   * @return moodle_url export file url
2159   * @deprecated since Moodle 4.0 MDL-71573
2160   * @see qbank_exportquestions\exportquestions_helper
2161   * @todo Final deprecation on Moodle 4.4 MDL-72438
2162   */
2163  function question_make_export_url($contextid, $categoryid, $format, $withcategories,
2164                                    $withcontexts, $filename) {
2165      debugging('Function question_make_export_url() has been deprecated and moved to qbank_exportquestions plugin,
2166      Please use qbank_exportquestions\exportquestions_helper::question_make_export_url() instead.', DEBUG_DEVELOPER);
2167  
2168      return \qbank_exportquestions\exportquestions_helper::question_make_export_url($contextid, $categoryid, $format,
2169          $withcategories, $withcontexts, $filename);
2170  }
2171  
2172  /**
2173   * Get the URL to export a single question (exportone.php).
2174   *
2175   * @param stdClass|question_definition $question the question definition as obtained from
2176   *      question_bank::load_question_data() or question_bank::make_question().
2177   *      (Only ->id and ->contextid are used.)
2178   * @return moodle_url the requested URL.
2179   * @deprecated since Moodle 4.0
2180   * @see \qbank_exporttoxml\helper::question_get_export_single_question_url()
2181   * @todo Final deprecation on Moodle 4.4 MDL-72438
2182   */
2183  function question_get_export_single_question_url($question) {
2184      debugging('Function question_get_export_single_question_url() has been deprecated and moved to qbank_exporttoxml plugin,
2185       please use qbank_exporttoxml\helper::question_get_export_single_question_url() instead.', DEBUG_DEVELOPER);
2186      qbank_exporttoxml\helper::question_get_export_single_question_url($question);
2187  }
2188  
2189  /**
2190   * Remove stale questions from a category.
2191   *
2192   * While questions should not be left behind when they are not used any more,
2193   * it does happen, maybe via restore, or old logic, or uncovered scenarios. When
2194   * this happens, the users are unable to delete the question category unless
2195   * they move those stale questions to another one category, but to them the
2196   * category is empty as it does not contain anything. The purpose of this function
2197   * is to detect the questions that may have gone stale and remove them.
2198   *
2199   * You will typically use this prior to checking if the category contains questions.
2200   *
2201   * The stale questions (unused and hidden to the user) handled are:
2202   * - hidden questions
2203   * - random questions
2204   *
2205   * @param int $categoryid The category ID.
2206   * @deprecated since Moodle 4.0 MDL-71585
2207   * @see qbank_managecategories\helper
2208   * @todo Final deprecation on Moodle 4.4 MDL-72438
2209   */
2210  function question_remove_stale_questions_from_category($categoryid) {
2211      debugging('Function question_remove_stale_questions_from_category()
2212      has been deprecated and moved to qbank_managecategories plugin,
2213      Please use qbank_managecategories\helper::question_remove_stale_questions_from_category() instead.',
2214          DEBUG_DEVELOPER);
2215      \qbank_managecategories\helper::question_remove_stale_questions_from_category($categoryid);
2216  }
2217  
2218  /**
2219   * Private method, only for the use of add_indented_names().
2220   *
2221   * Recursively adds an indentedname field to each category, starting with the category
2222   * with id $id, and dealing with that category and all its children, and
2223   * return a new array, with those categories in the right order.
2224   *
2225   * @param array $categories an array of categories which has had childids
2226   *          fields added by flatten_category_tree(). Passed by reference for
2227   *          performance only. It is not modfied.
2228   * @param int $id the category to start the indenting process from.
2229   * @param int $depth the indent depth. Used in recursive calls.
2230   * @param int $nochildrenof
2231   * @return array a new array of categories, in the right order for the tree.
2232   * @deprecated since Moodle 4.0 MDL-71585
2233   * @see qbank_managecategories\helper
2234   * @todo Final deprecation on Moodle 4.4 MDL-72438
2235   */
2236  function flatten_category_tree(&$categories, $id, $depth = 0, $nochildrenof = -1) {
2237      debugging('Function flatten_category_tree() has been deprecated and moved to qbank_managecategories plugin,
2238      Please use qbank_managecategories\helper::flatten_category_tree() instead.', DEBUG_DEVELOPER);
2239      return \qbank_managecategories\helper::flatten_category_tree($categories, $id, $depth, $nochildrenof);
2240  }
2241  
2242  /**
2243   * Format categories into an indented list reflecting the tree structure.
2244   *
2245   * @param array $categories An array of category objects, for example from the.
2246   * @param int $nochildrenof
2247   * @return array The formatted list of categories.
2248   * @deprecated since Moodle 4.0 MDL-71585
2249   * @see qbank_managecategories\helper
2250   * @todo Final deprecation on Moodle 4.4 MDL-72438
2251   */
2252  function add_indented_names($categories, $nochildrenof = -1) {
2253      debugging('Function add_indented_names() has been deprecated and moved to qbank_managecategories plugin,
2254      Please use qbank_managecategories\helper::add_indented_names() instead.', DEBUG_DEVELOPER);
2255      return \qbank_managecategories\helper::add_indented_names($categories, $nochildrenof);
2256  }
2257  
2258  /**
2259   * Output a select menu of question categories.
2260   * Categories from this course and (optionally) published categories from other courses
2261   * are included. Optionally, only categories the current user may edit can be included.
2262   *
2263   * @param array $contexts
2264   * @param bool $top
2265   * @param int $currentcat
2266   * @param integer $selected optionally, the id of a category to be selected by
2267   *      default in the dropdown.
2268   * @param int $nochildrenof
2269   * @deprecated since Moodle 4.0 MDL-71585
2270   * @see qbank_managecategories\helper
2271   * @todo Final deprecation on Moodle 4.4 MDL-72438
2272   */
2273  function question_category_select_menu($contexts, $top = false, $currentcat = 0,
2274                                         $selected = "", $nochildrenof = -1) {
2275      debugging('Function question_category_select_menu() has been deprecated and moved to qbank_managecategories plugin,
2276      Please use qbank_managecategories\helper::question_category_select_menu() instead.', DEBUG_DEVELOPER);
2277      \qbank_managecategories\helper::question_category_select_menu($contexts, $top, $currentcat, $selected, $nochildrenof);
2278  }
2279  
2280  /**
2281   * Get all the category objects, including a count of the number of questions in that category,
2282   * for all the categories in the lists $contexts.
2283   *
2284   * @param mixed $contexts either a single contextid, or a comma-separated list of context ids.
2285   * @param string $sortorder used as the ORDER BY clause in the select statement.
2286   * @param bool $top Whether to return the top categories or not.
2287   * @return array of category objects.
2288   * @deprecated since Moodle 4.0 MDL-71585
2289   * @see qbank_managecategories\helper
2290   * @todo Final deprecation on Moodle 4.4 MDL-72438
2291   */
2292  function get_categories_for_contexts($contexts, $sortorder = 'parent, sortorder, name ASC', $top = false) {
2293      debugging('Function get_categories_for_contexts() has been deprecated and moved to qbank_managecategories plugin,
2294      Please use qbank_managecategories\helper::get_categories_for_contexts() instead.', DEBUG_DEVELOPER);
2295      return \qbank_managecategories\helper::get_categories_for_contexts($contexts, $sortorder, $top);
2296  }
2297  
2298  /**
2299   * Output an array of question categories.
2300   *
2301   * @param array $contexts The list of contexts.
2302   * @param bool $top Whether to return the top categories or not.
2303   * @param int $currentcat
2304   * @param bool $popupform
2305   * @param int $nochildrenof
2306   * @param boolean $escapecontextnames Whether the returned name of the thing is to be HTML escaped or not.
2307   * @return array
2308   * @deprecated since Moodle 4.0 MDL-71585
2309   * @see qbank_managecategories\helper
2310   * @todo Final deprecation on Moodle 4.4 MDL-72438
2311   */
2312  function question_category_options($contexts, $top = false, $currentcat = 0,
2313                                     $popupform = false, $nochildrenof = -1, $escapecontextnames = true) {
2314      debugging('Function question_category_options() has been deprecated and moved to qbank_managecategories plugin,
2315      Please use qbank_managecategories\helper::question_category_options() instead.', DEBUG_DEVELOPER);
2316      return \qbank_managecategories\helper::question_category_options($contexts, $top, $currentcat,
2317          $popupform, $nochildrenof, $escapecontextnames);
2318  }
2319  
2320  /**
2321   * Add context in categories key.
2322   *
2323   * @param array $categories The list of categories.
2324   * @return array
2325   * @deprecated since Moodle 4.0 MDL-71585
2326   * @see qbank_managecategories\helper
2327   * @todo Final deprecation on Moodle 4.4 MDL-72438
2328   */
2329  function question_add_context_in_key($categories) {
2330      debugging('Function question_add_context_in_key() has been deprecated and moved to qbank_managecategories plugin,
2331      Please use qbank_managecategories\helper::question_add_context_in_key() instead.', DEBUG_DEVELOPER);
2332      return \qbank_managecategories\helper::question_add_context_in_key($categories);
2333  }
2334  
2335  /**
2336   * Finds top categories in the given categories hierarchy and replace their name with a proper localised string.
2337   *
2338   * @param array $categories An array of question categories.
2339   * @param boolean $escape Whether the returned name of the thing is to be HTML escaped or not.
2340   * @return array The same question category list given to the function, with the top category names being translated.
2341   * @deprecated since Moodle 4.0 MDL-71585
2342   * @see qbank_managecategories\helper
2343   * @todo Final deprecation on Moodle 4.4 MDL-72438
2344   */
2345  function question_fix_top_names($categories, $escape = true) {
2346      debugging('Function question_fix_top_names() has been deprecated and moved to qbank_managecategories plugin,
2347      Please use qbank_managecategories\helper::question_fix_top_names() instead.', DEBUG_DEVELOPER);
2348      return \qbank_managecategories\helper::question_fix_top_names($categories, $escape);
2349  }