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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                     qc.contextid 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               WHERE q.id = ?';
 361      $questiondata = $DB->get_record_sql($sql, [$question->id]);
 362  
 363      $questionstocheck = [$question->id];
 364  
 365      if ($question->parent) {
 366          $questionstocheck[] = $question->parent;
 367      }
 368  
 369      // Do not delete a question if it is used by an activity module. Just mark the version hidden.
 370      if (questions_in_use($questionstocheck)) {
 371          $DB->set_field('question_versions', 'status',
 372                  question_version_status::QUESTION_STATUS_HIDDEN, ['questionid' => $questionid]);
 373          return;
 374      }
 375  
 376      // This sometimes happens in old sites with bad data.
 377      if (!$questiondata->contextid) {
 378          debugging('Deleting question ' . $question->id . ' which is no longer linked to a context. ' .
 379              'Assuming system context to avoid errors, but this may mean that some data like files, ' .
 380              'tags, are not cleaned up.');
 381          $questiondata->contextid = context_system::instance()->id;
 382          $questiondata->categoryid = 0;
 383      }
 384  
 385      // Delete previews of the question.
 386      $dm = new question_engine_data_mapper();
 387      $dm->delete_previews($question->id);
 388  
 389      // Delete questiontype-specific data.
 390      question_bank::get_qtype($question->qtype, false)->delete_question($question->id, $questiondata->contextid);
 391  
 392      // Delete all tag instances.
 393      core_tag_tag::remove_all_item_tags('core_question', 'question', $question->id);
 394  
 395      // Delete the custom filed data for the question.
 396      $customfieldhandler = qbank_customfields\customfield\question_handler::create();
 397      $customfieldhandler->delete_instance($question->id);
 398  
 399      // Now recursively delete all child questions
 400      if ($children = $DB->get_records('question',
 401              array('parent' => $questionid), '', 'id, qtype')) {
 402          foreach ($children as $child) {
 403              if ($child->id != $questionid) {
 404                  question_delete_question($child->id);
 405              }
 406          }
 407      }
 408  
 409      // Delete question comments.
 410      $DB->delete_records('comments', ['itemid' => $questionid, 'component' => 'qbank_comment',
 411                                              'commentarea' => 'question']);
 412      // Finally delete the question record itself.
 413      $DB->delete_records('question', ['id' => $question->id]);
 414      $DB->delete_records('question_versions', ['id' => $questiondata->versionid]);
 415      $DB->delete_records('question_references',
 416          [
 417              'version' => $questiondata->version,
 418              'questionbankentryid' => $questiondata->entryid,
 419          ]);
 420      delete_question_bank_entry($questiondata->entryid);
 421      question_bank::notify_question_edited($question->id);
 422  
 423      // Log the deletion of this question.
 424      $question->category = $questiondata->categoryid;
 425      $question->contextid = $questiondata->contextid;
 426      $event = \core\event\question_deleted::create_from_question_instance($question);
 427      $event->add_record_snapshot('question', $question);
 428      $event->trigger();
 429  }
 430  
 431  /**
 432   * All question categories and their questions are deleted for this context id.
 433   *
 434   * @param int $contextid The contextid to delete question categories from
 435   * @return array only returns an empty array for backwards compatibility.
 436   */
 437  function question_delete_context($contextid): array {
 438      global $DB;
 439  
 440      $fields = 'id, parent, name, contextid';
 441      if ($categories = $DB->get_records('question_categories', ['contextid' => $contextid], 'parent', $fields)) {
 442          // Sort categories following their tree (parent-child) relationships this will make the feedback more readable.
 443          $categories = sort_categories_by_tree($categories);
 444          foreach ($categories as $category) {
 445              question_category_delete_safe($category);
 446          }
 447      }
 448      return [];
 449  }
 450  
 451  /**
 452   * All question categories and their questions are deleted for this course.
 453   *
 454   * @param stdClass $course an object representing the activity
 455   * @param bool $notused this argument is not used any more. Kept for backwards compatibility.
 456   * @return bool always true.
 457   */
 458  function question_delete_course($course, $notused = false): bool {
 459      $coursecontext = context_course::instance($course->id);
 460      question_delete_context($coursecontext->id);
 461      return true;
 462  }
 463  
 464  /**
 465   * Category is about to be deleted,
 466   * 1/ All question categories and their questions are deleted for this course category.
 467   * 2/ All questions are moved to new category
 468   *
 469   * @param stdClass|core_course_category $category course category object
 470   * @param stdClass|core_course_category $newcategory empty means everything deleted, otherwise id of
 471   *      category where content moved
 472   * @param bool $notused this argument is no longer used. Kept for backwards compatibility.
 473   * @return boolean
 474   */
 475  function question_delete_course_category($category, $newcategory, $notused=false): bool {
 476      global $DB;
 477  
 478      $context = context_coursecat::instance($category->id);
 479      if (empty($newcategory)) {
 480          question_delete_context($context->id);
 481  
 482      } else {
 483          // Move question categories to the new context.
 484          if (!$newcontext = context_coursecat::instance($newcategory->id)) {
 485              return false;
 486          }
 487  
 488          // Only move question categories if there is any question category at all!
 489          if ($topcategory = question_get_top_category($context->id)) {
 490              $newtopcategory = question_get_top_category($newcontext->id, true);
 491  
 492              question_move_category_to_context($topcategory->id, $context->id, $newcontext->id);
 493              $DB->set_field('question_categories', 'parent', $newtopcategory->id, ['parent' => $topcategory->id]);
 494              // Now delete the top category.
 495              $DB->delete_records('question_categories', ['id' => $topcategory->id]);
 496          }
 497      }
 498  
 499      return true;
 500  }
 501  
 502  /**
 503   * Creates a new category to save the questions in use.
 504   *
 505   * @param array $questionids of question ids
 506   * @param object $newcontextid the context to create the saved category in.
 507   * @param string $oldplace a textual description of the think being deleted,
 508   *      e.g. from get_context_name
 509   * @param object $newcategory
 510   * @return mixed false on
 511   */
 512  function question_save_from_deletion($questionids, $newcontextid, $oldplace, $newcategory = null) {
 513      global $DB;
 514  
 515      // Make a category in the parent context to move the questions to.
 516      if (is_null($newcategory)) {
 517          $newcategory = new stdClass();
 518          $newcategory->parent = question_get_top_category($newcontextid, true)->id;
 519          $newcategory->contextid = $newcontextid;
 520          // Max length of column name in question_categories is 255.
 521          $newcategory->name = shorten_text(get_string('questionsrescuedfrom', 'question', $oldplace), 255);
 522          $newcategory->info = get_string('questionsrescuedfrominfo', 'question', $oldplace);
 523          $newcategory->sortorder = 999;
 524          $newcategory->stamp = make_unique_id_code();
 525          $newcategory->id = $DB->insert_record('question_categories', $newcategory);
 526      }
 527  
 528      // Move any remaining questions to the 'saved' category.
 529      if (!question_move_questions_to_category($questionids, $newcategory->id)) {
 530          return false;
 531      }
 532      return $newcategory;
 533  }
 534  
 535  /**
 536   * All question categories and their questions are deleted for this activity.
 537   *
 538   * @param object $cm the course module object representing the activity
 539   * @param bool $notused the argument is not used any more. Kept for backwards compatibility.
 540   * @return boolean
 541   */
 542  function question_delete_activity($cm, $notused = false): bool {
 543      $modcontext = context_module::instance($cm->id);
 544      question_delete_context($modcontext->id);
 545      return true;
 546  }
 547  
 548  /**
 549   * This function will handle moving all tag instances to a new context for a
 550   * given list of questions.
 551   *
 552   * Questions can be tagged in up to two contexts:
 553   * 1.) The context the question exists in.
 554   * 2.) The course context (if the question context is a higher context.
 555   *     E.g. course category context or system context.
 556   *
 557   * This means a question that exists in a higher context (e.g. course cat or
 558   * system context) may have multiple groups of tags in any number of child
 559   * course contexts.
 560   *
 561   * Questions in the course category context can be move "down" a context level
 562   * into one of their child course contexts or activity contexts which affects the
 563   * availability of that question in other courses / activities.
 564   *
 565   * In this case it makes the questions no longer available in the other course or
 566   * activity contexts so we need to make sure that the tag instances in those other
 567   * contexts are removed.
 568   *
 569   * @param stdClass[] $questions The list of question being moved (must include
 570   *                              the id and contextid)
 571   * @param context $newcontext The Moodle context the questions are being moved to
 572   */
 573  function question_move_question_tags_to_new_context(array $questions, context $newcontext): void {
 574      // If the questions are moving to a new course/activity context then we need to
 575      // find any existing tag instances from any unavailable course contexts and
 576      // delete them because they will no longer be applicable (we don't support
 577      // tagging questions across courses).
 578      $instancestodelete = [];
 579      $instancesfornewcontext = [];
 580      $newcontextparentids = $newcontext->get_parent_context_ids();
 581      $questionids = array_map(function($question) {
 582          return $question->id;
 583      }, $questions);
 584      $questionstagobjects = core_tag_tag::get_items_tags('core_question', 'question', $questionids);
 585  
 586      foreach ($questions as $question) {
 587          $tagobjects = $questionstagobjects[$question->id] ?? [];
 588  
 589          foreach ($tagobjects as $tagobject) {
 590              $tagid = $tagobject->taginstanceid;
 591              $tagcontextid = $tagobject->taginstancecontextid;
 592              $istaginnewcontext = $tagcontextid == $newcontext->id;
 593              $istaginquestioncontext = $tagcontextid == $question->contextid;
 594  
 595              if ($istaginnewcontext) {
 596                  // This tag instance is already in the correct context so we can
 597                  // ignore it.
 598                  continue;
 599              }
 600  
 601              if ($istaginquestioncontext) {
 602                  // This tag instance is in the question context so it needs to be
 603                  // updated.
 604                  $instancesfornewcontext[] = $tagid;
 605                  continue;
 606              }
 607  
 608              // These tag instances are in neither the new context nor the
 609              // question context so we need to determine what to do based on
 610              // the context they are in and the new question context.
 611              $tagcontext = context::instance_by_id($tagcontextid);
 612              $tagcoursecontext = $tagcontext->get_course_context(false);
 613              // The tag is in a course context if get_course_context() returns
 614              // itself.
 615              $istaginstancecontextcourse = !empty($tagcoursecontext)
 616                  && $tagcontext->id == $tagcoursecontext->id;
 617  
 618              if ($istaginstancecontextcourse) {
 619                  // If the tag instance is in a course context we need to add some
 620                  // special handling.
 621                  $tagcontextparentids = $tagcontext->get_parent_context_ids();
 622                  $isnewcontextaparent = in_array($newcontext->id, $tagcontextparentids);
 623                  $isnewcontextachild = in_array($tagcontext->id, $newcontextparentids);
 624  
 625                  if ($isnewcontextaparent) {
 626                      // If the tag instance is a course context tag and the new
 627                      // context is still a parent context to the tag context then
 628                      // we can leave this tag where it is.
 629                      continue;
 630                  } else if ($isnewcontextachild) {
 631                      // If the new context is a child context (e.g. activity) of this
 632                      // tag instance then we should move all of this tag instance
 633                      // down into the activity context along with the question.
 634                      $instancesfornewcontext[] = $tagid;
 635                  } else {
 636                      // If the tag is in a course context that is no longer a parent
 637                      // or child of the new context then this tag instance should be
 638                      // removed.
 639                      $instancestodelete[] = $tagid;
 640                  }
 641              } else {
 642                  // This is a catch all for any tag instances not in the question
 643                  // context or a course context. These tag instances should be
 644                  // updated to the new context id. This will clean up old invalid
 645                  // data.
 646                  $instancesfornewcontext[] = $tagid;
 647              }
 648          }
 649      }
 650  
 651      if (!empty($instancestodelete)) {
 652          // Delete any course context tags that may no longer be valid.
 653          core_tag_tag::delete_instances_by_id($instancestodelete);
 654      }
 655  
 656      if (!empty($instancesfornewcontext)) {
 657          // Update the tag instances to the new context id.
 658          core_tag_tag::change_instances_context($instancesfornewcontext, $newcontext);
 659      }
 660  }
 661  
 662  /**
 663   * Check if an idnumber exist in the category.
 664   *
 665   * @param int $questionidnumber
 666   * @param int $categoryid
 667   * @param int $limitfrom
 668   * @param int $limitnum
 669   * @return array
 670   */
 671  function idnumber_exist_in_question_category($questionidnumber, $categoryid, $limitfrom = 0, $limitnum = 1): array {
 672      global $DB;
 673      $response  = false;
 674      $record = [];
 675      // Check if the idnumber exist in the category.
 676      $sql = 'SELECT qbe.idnumber
 677                FROM {question_bank_entries} qbe
 678               WHERE qbe.idnumber LIKE ?
 679                 AND qbe.questioncategoryid = ?
 680            ORDER BY qbe.idnumber DESC';
 681      $questionrecord = $DB->record_exists_sql($sql, [$questionidnumber, $categoryid]);
 682      if ((string) $questionidnumber !== '' && $questionrecord) {
 683          $record = $DB->get_records_sql($sql, [$questionidnumber . '_%', $categoryid], 0, 1);
 684          $response  = true;
 685      }
 686  
 687      return [$response, $record];
 688  }
 689  
 690  /**
 691   * This function should be considered private to the question bank, it is called from
 692   * question/editlib.php question/contextmoveq.php and a few similar places to to the
 693   * work of actually moving questions and associated data. However, callers of this
 694   * function also have to do other work, which is why you should not call this method
 695   * directly from outside the questionbank.
 696   *
 697   * @param array $questionids of question ids.
 698   * @param integer $newcategoryid the id of the category to move to.
 699   * @return bool
 700   */
 701  function question_move_questions_to_category($questionids, $newcategoryid): bool {
 702      global $DB;
 703  
 704      $newcategorydata = $DB->get_record('question_categories', ['id' => $newcategoryid]);
 705      if (!$newcategorydata) {
 706          return false;
 707      }
 708      list($questionidcondition, $params) = $DB->get_in_or_equal($questionids);
 709  
 710      $sql = "SELECT qv.id as versionid,
 711                     qbe.id as entryid,
 712                     qc.id as category,
 713                     qc.contextid as contextid,
 714                     q.id,
 715                     q.qtype,
 716                     qbe.idnumber
 717                FROM {question} q
 718                JOIN {question_versions} qv ON qv.questionid = q.id
 719                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
 720                JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid
 721               WHERE q.id $questionidcondition
 722                     OR (q.parent <> 0 AND q.parent $questionidcondition)";
 723  
 724      // Also, we need to move children questions.
 725      $params = array_merge($params, $params);
 726      $questions = $DB->get_records_sql($sql, $params);
 727      foreach ($questions as $question) {
 728          if ($newcategorydata->contextid != $question->contextid) {
 729              question_bank::get_qtype($question->qtype)->move_files(
 730                      $question->id, $question->contextid, $newcategorydata->contextid);
 731          }
 732          // Check whether there could be a clash of idnumbers in the new category.
 733          list($idnumberclash, $rec) = idnumber_exist_in_question_category($question->idnumber, $newcategoryid);
 734          if ($idnumberclash) {
 735              $unique = 1;
 736              if (count($rec)) {
 737                  $rec = reset($rec);
 738                  $idnumber = $rec->idnumber;
 739                  if (strpos($idnumber, '_') !== false) {
 740                      $unique = substr($idnumber, strpos($idnumber, '_') + 1) + 1;
 741                  }
 742              }
 743              // For the move process, add a numerical increment to the idnumber. This means that if a question is
 744              // mistakenly moved then the idnumber will not be completely lost.
 745              $qbankentry = new stdClass();
 746              $qbankentry->id = $question->entryid;
 747              $qbankentry->idnumber = $question->idnumber . '_' . $unique;
 748              $DB->update_record('question_bank_entries', $qbankentry);
 749          }
 750  
 751          // Update the entry to the new category id.
 752          $entry = new stdClass();
 753          $entry->id = $question->entryid;
 754          $entry->questioncategoryid = $newcategorydata->id;
 755          $DB->update_record('question_bank_entries', $entry);
 756  
 757          // Log this question move.
 758          $event = \core\event\question_moved::create_from_question_instance($question, context::instance_by_id($question->contextid),
 759                  ['oldcategoryid' => $question->category, 'newcategoryid' => $newcategorydata->id]);
 760          $event->trigger();
 761      }
 762  
 763      $newcontext = context::instance_by_id($newcategorydata->contextid);
 764      question_move_question_tags_to_new_context($questions, $newcontext);
 765  
 766      // TODO Deal with datasets.
 767  
 768      // Purge these questions from the cache.
 769      foreach ($questions as $question) {
 770          question_bank::notify_question_edited($question->id);
 771      }
 772  
 773      return true;
 774  }
 775  
 776  /**
 777   * Update the questioncontextid field for all question_set_references records given a new context id
 778   *
 779   * @param int $oldcategoryid Old category to be moved.
 780   * @param int $newcatgoryid New category that will receive the questions.
 781   * @param int $oldcontextid Old context to be moved.
 782   * @param int $newcontextid New context that will receive the questions.
 783   * @param bool $delete If the action is delete.
 784   * @throws dml_exception
 785   */
 786  function move_question_set_references(int $oldcategoryid, int $newcatgoryid,
 787                                        int $oldcontextid, int $newcontextid, bool $delete = false): void {
 788      global $DB;
 789  
 790      if ($delete || $oldcontextid !== $newcontextid) {
 791          $setreferences = $DB->get_recordset('question_set_references', ['questionscontextid' => $oldcontextid]);
 792          foreach ($setreferences as $setreference) {
 793              $filter = json_decode($setreference->filtercondition);
 794              if (isset($filter->questioncategoryid)) {
 795                  if ((int)$filter->questioncategoryid === $oldcategoryid) {
 796                      $setreference->questionscontextid = $newcontextid;
 797                      if ($oldcategoryid !== $newcatgoryid) {
 798                          $filter->questioncategoryid = $newcatgoryid;
 799                          $setreference->filtercondition = json_encode($filter);
 800                      }
 801                      $DB->update_record('question_set_references', $setreference);
 802                  }
 803              }
 804          }
 805          $setreferences->close();
 806      }
 807  }
 808  
 809  /**
 810   * This function helps move a question cateogry to a new context by moving all
 811   * the files belonging to all the questions to the new context.
 812   * Also moves subcategories.
 813   * @param integer $categoryid the id of the category being moved.
 814   * @param integer $oldcontextid the old context id.
 815   * @param integer $newcontextid the new context id.
 816   */
 817  function question_move_category_to_context($categoryid, $oldcontextid, $newcontextid): void {
 818      global $DB;
 819  
 820      $questions = [];
 821      $sql = "SELECT q.id, q.qtype
 822                FROM {question} q
 823                JOIN {question_versions} qv ON qv.questionid = q.id
 824                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
 825               WHERE qbe.questioncategoryid = ?";
 826  
 827      $questionids = $DB->get_records_sql_menu($sql, [$categoryid]);
 828      foreach ($questionids as $questionid => $qtype) {
 829          question_bank::get_qtype($qtype)->move_files($questionid, $oldcontextid, $newcontextid);
 830          // Purge this question from the cache.
 831          question_bank::notify_question_edited($questionid);
 832  
 833          $questions[] = (object) [
 834              'id' => $questionid,
 835              'contextid' => $oldcontextid
 836          ];
 837      }
 838  
 839      $newcontext = context::instance_by_id($newcontextid);
 840      question_move_question_tags_to_new_context($questions, $newcontext);
 841  
 842      $subcatids = $DB->get_records_menu('question_categories', ['parent' => $categoryid], '', 'id,1');
 843      foreach ($subcatids as $subcatid => $notused) {
 844          $DB->set_field('question_categories', 'contextid', $newcontextid, ['id' => $subcatid]);
 845          question_move_category_to_context($subcatid, $oldcontextid, $newcontextid);
 846      }
 847  }
 848  
 849  /**
 850   * Given a list of ids, load the basic information about a set of questions from
 851   * the questions table. The $join and $extrafields arguments can be used together
 852   * to pull in extra data. See, for example, the usage in mod/quiz/attemptlib.php, and
 853   * read the code below to see how the SQL is assembled. Throws exceptions on error.
 854   *
 855   * @param array $questionids array of question ids to load. If null, then all
 856   * questions matched by $join will be loaded.
 857   * @param string $extrafields extra SQL code to be added to the query.
 858   * @param string $join extra SQL code to be added to the query.
 859   * @param array $extraparams values for any placeholders in $join.
 860   * You must use named placeholders.
 861   * @param string $orderby what to order the results by. Optional, default is unspecified order.
 862   *
 863   * @return array partially complete question objects. You need to call get_question_options
 864   * on them before they can be properly used.
 865   */
 866  function question_preload_questions($questionids = null, $extrafields = '', $join = '', $extraparams = [], $orderby = ''): array {
 867      global $DB;
 868  
 869      if ($questionids === null) {
 870          $extracondition = '';
 871          $params = [];
 872      } else {
 873          if (empty($questionids)) {
 874              return [];
 875          }
 876  
 877          list($questionidcondition, $params) = $DB->get_in_or_equal($questionids, SQL_PARAMS_NAMED, 'qid0000');
 878          $extracondition = 'WHERE q.id ' . $questionidcondition;
 879      }
 880  
 881      if ($join) {
 882          $join = 'JOIN ' . $join;
 883      }
 884  
 885      if ($extrafields) {
 886          $extrafields = ', ' . $extrafields;
 887      }
 888  
 889      if ($orderby) {
 890          $orderby = 'ORDER BY ' . $orderby;
 891      }
 892  
 893      $sql = "SELECT q.*,
 894                     qc.id as category,
 895                     qv.status,
 896                     qv.id as versionid,
 897                     qv.version,
 898                     qv.questionbankentryid,
 899                     qc.contextid as contextid
 900                     {$extrafields}
 901                FROM {question} q
 902                JOIN {question_versions} qv
 903                  ON qv.questionid = q.id
 904                JOIN {question_bank_entries} qbe
 905                  ON qbe.id = qv.questionbankentryid
 906                JOIN {question_categories} qc
 907                  ON qc.id = qbe.questioncategoryid
 908                {$join}
 909                {$extracondition}
 910                {$orderby}";
 911  
 912      // Load the questions.
 913      $questions = $DB->get_records_sql($sql, $extraparams + $params);
 914      foreach ($questions as $question) {
 915          $question->_partiallyloaded = true;
 916      }
 917  
 918      return $questions;
 919  }
 920  
 921  /**
 922   * Load a set of questions, given a list of ids. The $join and $extrafields arguments can be used
 923   * together to pull in extra data. See, for example, the usage in mod/quiz/attempt.php, and
 924   * read the code below to see how the SQL is assembled. Throws exceptions on error.
 925   *
 926   * @param array $questionids array of question ids.
 927   * @param string $extrafields extra SQL code to be added to the query.
 928   * @param string $join extra SQL code to be added to the query.
 929   * @return array|string question objects.
 930   */
 931  function question_load_questions($questionids, $extrafields = '', $join = '') {
 932      $questions = question_preload_questions($questionids, $extrafields, $join);
 933  
 934      // Load the question type specific information.
 935      if (!get_question_options($questions)) {
 936          return get_string('questionloaderror', 'question');
 937      }
 938  
 939      return $questions;
 940  }
 941  
 942  /**
 943   * Private function to factor common code out of get_question_options().
 944   *
 945   * @param object $question the question to tidy.
 946   * @param stdClass $category The question_categories record for the given $question.
 947   * @param stdClass[]|null $tagobjects The tags for the given $question.
 948   * @param stdClass[]|null $filtercourses The courses to filter the course tags by.
 949   */
 950  function _tidy_question($question, $category, array $tagobjects = null, array $filtercourses = null): void {
 951      // Convert numeric fields to float. This prevents these being displayed as 1.0000000.
 952      $question->defaultmark += 0;
 953      $question->penalty += 0;
 954  
 955      // Indicate the question is now fully initialised.
 956      if (isset($question->_partiallyloaded)) {
 957          unset($question->_partiallyloaded);
 958      }
 959  
 960      $question->categoryobject = $category;
 961  
 962      // Add any tags we have been passed.
 963      if (!is_null($tagobjects)) {
 964          $categorycontext = context::instance_by_id($category->contextid);
 965          $sortedtagobjects = question_sort_tags($tagobjects, $categorycontext, $filtercourses);
 966          $question->coursetagobjects = $sortedtagobjects->coursetagobjects;
 967          $question->coursetags = $sortedtagobjects->coursetags;
 968          $question->tagobjects = $sortedtagobjects->tagobjects;
 969          $question->tags = $sortedtagobjects->tags;
 970      }
 971  
 972      // Load question-type specific fields.
 973      if (question_bank::is_qtype_installed($question->qtype)) {
 974          question_bank::get_qtype($question->qtype)->get_question_options($question);
 975      } else {
 976          $question->questiontext = html_writer::tag('p', get_string('warningmissingtype',
 977                  'qtype_missingtype')) . $question->questiontext;
 978      }
 979  }
 980  
 981  /**
 982   * Updates the question objects with question type specific
 983   * information by calling {@see get_question_options()}
 984   *
 985   * Can be called either with an array of question objects or with a single
 986   * question object.
 987   *
 988   * @param mixed $questions Either an array of question objects to be updated
 989   *         or just a single question object
 990   * @param bool $loadtags load the question tags from the tags table. Optional, default false.
 991   * @param stdClass[] $filtercourses The courses to filter the course tags by.
 992   * @return bool Indicates success or failure.
 993   */
 994  function get_question_options(&$questions, $loadtags = false, $filtercourses = null) {
 995      global $DB;
 996  
 997      $questionlist = is_array($questions) ? $questions : [$questions];
 998      $categoryids = [];
 999      $questionids = [];
1000  
1001      if (empty($questionlist)) {
1002          return true;
1003      }
1004  
1005      foreach ($questionlist as $question) {
1006          $questionids[] = $question->id;
1007          if (isset($question->category)) {
1008              $qcategoryid = $question->category;
1009          } else {
1010              $qcategoryid = get_question_bank_entry($question->id)->questioncategoryid;
1011              $question->questioncategoryid = $qcategoryid;
1012          }
1013  
1014          if (!in_array($qcategoryid, $categoryids)) {
1015              $categoryids[] = $qcategoryid;
1016          }
1017      }
1018  
1019      $categories = $DB->get_records_list('question_categories', 'id', $categoryids);
1020  
1021      if ($loadtags && core_tag_tag::is_enabled('core_question', 'question')) {
1022          $tagobjectsbyquestion = core_tag_tag::get_items_tags('core_question', 'question', $questionids);
1023      } else {
1024          $tagobjectsbyquestion = null;
1025      }
1026  
1027      foreach ($questionlist as $question) {
1028          if (is_null($tagobjectsbyquestion)) {
1029              $tagobjects = null;
1030          } else {
1031              $tagobjects = $tagobjectsbyquestion[$question->id];
1032          }
1033          $qcategoryid = $question->category ?? $question->questioncategoryid ??
1034              get_question_bank_entry($question->id)->questioncategoryid;
1035  
1036          _tidy_question($question, $categories[$qcategoryid], $tagobjects, $filtercourses);
1037      }
1038  
1039      return true;
1040  }
1041  
1042  /**
1043   * Sort question tags by course or normal tags.
1044   *
1045   * This function also search tag instances that may have a context id that don't match either a course or
1046   * question context and fix the data setting the correct context id.
1047   *
1048   * @param stdClass[] $tagobjects The tags for the given $question.
1049   * @param stdClass $categorycontext The question categories context.
1050   * @param stdClass[]|null $filtercourses The courses to filter the course tags by.
1051   * @return stdClass $sortedtagobjects Sorted tag objects.
1052   */
1053  function question_sort_tags($tagobjects, $categorycontext, $filtercourses = null): stdClass {
1054  
1055      // Questions can have two sets of tag instances. One set at the
1056      // course context level and another at the context the question
1057      // belongs to (e.g. course category, system etc).
1058      $sortedtagobjects = new stdClass();
1059      $sortedtagobjects->coursetagobjects = [];
1060      $sortedtagobjects->coursetags = [];
1061      $sortedtagobjects->tagobjects = [];
1062      $sortedtagobjects->tags = [];
1063      $taginstanceidstonormalise = [];
1064      $filtercoursecontextids = [];
1065      $hasfiltercourses = !empty($filtercourses);
1066  
1067      if ($hasfiltercourses) {
1068          // If we're being asked to filter the course tags by a set of courses
1069          // then get the context ids to filter below.
1070          $filtercoursecontextids = array_map(function($course) {
1071              $coursecontext = context_course::instance($course->id);
1072              return $coursecontext->id;
1073          }, $filtercourses);
1074      }
1075  
1076      foreach ($tagobjects as $tagobject) {
1077          $tagcontextid = $tagobject->taginstancecontextid;
1078          $tagcontext = context::instance_by_id($tagcontextid);
1079          $tagcoursecontext = $tagcontext->get_course_context(false);
1080          // This is a course tag if the tag context is a course context which
1081          // doesn't match the question's context. Any tag in the question context
1082          // is not considered a course tag, it belongs to the question.
1083          $iscoursetag = $tagcoursecontext
1084              && $tagcontext->id == $tagcoursecontext->id
1085              && $tagcontext->id != $categorycontext->id;
1086  
1087          if ($iscoursetag) {
1088              // Any tag instance in a course context level is considered a course tag.
1089              if (!$hasfiltercourses || in_array($tagcontextid, $filtercoursecontextids)) {
1090                  // Add the tag to the list of course tags if we aren't being
1091                  // asked to filter or if this tag is in the list of courses
1092                  // we're being asked to filter by.
1093                  $sortedtagobjects->coursetagobjects[] = $tagobject;
1094                  $sortedtagobjects->coursetags[$tagobject->id] = $tagobject->get_display_name();
1095              }
1096          } else {
1097              // All non course context level tag instances or tags in the question
1098              // context belong to the context that the question was created in.
1099              $sortedtagobjects->tagobjects[] = $tagobject;
1100              $sortedtagobjects->tags[$tagobject->id] = $tagobject->get_display_name();
1101  
1102              // Due to legacy tag implementations that don't force the recording
1103              // of a context id, some tag instances may have context ids that don't
1104              // match either a course context or the question context. In this case
1105              // we should take the opportunity to fix up the data and set the correct
1106              // context id.
1107              if ($tagcontext->id != $categorycontext->id) {
1108                  $taginstanceidstonormalise[] = $tagobject->taginstanceid;
1109                  // Update the object properties to reflect the DB update that will
1110                  // happen below.
1111                  $tagobject->taginstancecontextid = $categorycontext->id;
1112              }
1113          }
1114      }
1115  
1116      if (!empty($taginstanceidstonormalise)) {
1117          // If we found any tag instances with incorrect context id data then we can
1118          // correct those values now by setting them to the question context id.
1119          core_tag_tag::change_instances_context($taginstanceidstonormalise, $categorycontext);
1120      }
1121  
1122      return $sortedtagobjects;
1123  }
1124  
1125  /**
1126   * Print the icon for the question type
1127   *
1128   * @param object $question The question object for which the icon is required.
1129   *       Only $question->qtype is used.
1130   * @return string the HTML for the img tag.
1131   */
1132  function print_question_icon($question): string {
1133      global $PAGE;
1134  
1135      if (gettype($question->qtype) == 'object') {
1136          $qtype = $question->qtype->name();
1137      } else {
1138          // Assume string.
1139          $qtype = $question->qtype;
1140      }
1141  
1142      return $PAGE->get_renderer('question', 'bank')->qtype_icon($qtype);
1143  }
1144  
1145  // CATEGORY FUNCTIONS.
1146  
1147  /**
1148   * Returns the categories with their names ordered following parent-child relationships.
1149   * finally it tries to return pending categories (those being orphaned, whose parent is
1150   * incorrect) to avoid missing any category from original array.
1151   *
1152   * @param array $categories
1153   * @param int $id
1154   * @param int $level
1155   * @return array
1156   */
1157  function sort_categories_by_tree(&$categories, $id = 0, $level = 1): array {
1158      global $DB;
1159  
1160      $children = [];
1161      $keys = array_keys($categories);
1162  
1163      foreach ($keys as $key) {
1164          if (!isset($categories[$key]->processed) && $categories[$key]->parent == $id) {
1165              $children[$key] = $categories[$key];
1166              $categories[$key]->processed = true;
1167              $children = $children + sort_categories_by_tree(
1168                      $categories, $children[$key]->id, $level + 1);
1169          }
1170      }
1171      // If level = 1, we have finished, try to look for non processed categories (bad parent) and sort them too.
1172      if ($level == 1) {
1173          foreach ($keys as $key) {
1174              // If not processed and it's a good candidate to start (because its parent doesn't exist in the course).
1175              if (!isset($categories[$key]->processed) && !$DB->record_exists('question_categories',
1176                      array('contextid' => $categories[$key]->contextid,
1177                              'id' => $categories[$key]->parent))) {
1178                  $children[$key] = $categories[$key];
1179                  $categories[$key]->processed = true;
1180                  $children = $children + sort_categories_by_tree(
1181                          $categories, $children[$key]->id, $level + 1);
1182              }
1183          }
1184      }
1185      return $children;
1186  }
1187  
1188  /**
1189   * Get the default category for the context.
1190   *
1191   * @param integer $contextid a context id.
1192   * @return object|bool the default question category for that context, or false if none.
1193   */
1194  function question_get_default_category($contextid) {
1195      global $DB;
1196      $category = $DB->get_records_select('question_categories', 'contextid = ? AND parent <> 0',
1197                                          [$contextid], 'id', '*', 0, 1);
1198      if (!empty($category)) {
1199          return reset($category);
1200      } else {
1201          return false;
1202      }
1203  }
1204  
1205  /**
1206   * Gets the top category in the given context.
1207   * This function can optionally create the top category if it doesn't exist.
1208   *
1209   * @param int $contextid A context id.
1210   * @param bool $create Whether create a top category if it doesn't exist.
1211   * @return bool|stdClass The top question category for that context, or false if none.
1212   */
1213  function question_get_top_category($contextid, $create = false) {
1214      global $DB;
1215      $category = $DB->get_record('question_categories', ['contextid' => $contextid, 'parent' => 0]);
1216  
1217      if (!$category && $create) {
1218          // We need to make one.
1219          $category = new stdClass();
1220          $category->name = 'top'; // A non-real name for the top category. It will be localised at the display time.
1221          $category->info = '';
1222          $category->contextid = $contextid;
1223          $category->parent = 0;
1224          $category->sortorder = 0;
1225          $category->stamp = make_unique_id_code();
1226          $category->id = $DB->insert_record('question_categories', $category);
1227      }
1228  
1229      return $category;
1230  }
1231  
1232  /**
1233   * Gets the list of top categories in the given contexts in the array("categoryid,categorycontextid") format.
1234   *
1235   * @param array $contextids List of context ids
1236   * @return array
1237   */
1238  function question_get_top_categories_for_contexts($contextids): array {
1239      global $DB;
1240  
1241      $concatsql = $DB->sql_concat_join("','", ['id', 'contextid']);
1242      list($insql, $params) = $DB->get_in_or_equal($contextids);
1243      $sql = "SELECT $concatsql
1244                FROM {question_categories}
1245               WHERE contextid $insql
1246                 AND parent = 0";
1247  
1248      $topcategories = $DB->get_fieldset_sql($sql, $params);
1249  
1250      return $topcategories;
1251  }
1252  
1253  /**
1254   * Gets the default category in the most specific context.
1255   * If no categories exist yet then default ones are created in all contexts.
1256   *
1257   * @param array $contexts  The context objects for this context and all parent contexts.
1258   * @return object The default category - the category in the course context
1259   */
1260  function question_make_default_categories($contexts): object {
1261      global $DB;
1262      static $preferredlevels = array(
1263          CONTEXT_COURSE => 4,
1264          CONTEXT_MODULE => 3,
1265          CONTEXT_COURSECAT => 2,
1266          CONTEXT_SYSTEM => 1,
1267      );
1268  
1269      $toreturn = null;
1270      $preferredness = 0;
1271      // If it already exists, just return it.
1272      foreach ($contexts as $key => $context) {
1273          $topcategory = question_get_top_category($context->id, true);
1274          if (!$exists = $DB->record_exists("question_categories",
1275                  array('contextid' => $context->id, 'parent' => $topcategory->id))) {
1276              // Otherwise, we need to make one.
1277              $category = new stdClass();
1278              $contextname = $context->get_context_name(false, true);
1279              // Max length of name field is 255.
1280              $category->name = shorten_text(get_string('defaultfor', 'question', $contextname), 255);
1281              $category->info = get_string('defaultinfofor', 'question', $contextname);
1282              $category->contextid = $context->id;
1283              $category->parent = $topcategory->id;
1284              // By default, all categories get this number, and are sorted alphabetically.
1285              $category->sortorder = 999;
1286              $category->stamp = make_unique_id_code();
1287              $category->id = $DB->insert_record('question_categories', $category);
1288          } else {
1289              $category = question_get_default_category($context->id);
1290          }
1291          $thispreferredness = $preferredlevels[$context->contextlevel];
1292          if (has_any_capability(array('moodle/question:usemine', 'moodle/question:useall'), $context)) {
1293              $thispreferredness += 10;
1294          }
1295          if ($thispreferredness > $preferredness) {
1296              $toreturn = $category;
1297              $preferredness = $thispreferredness;
1298          }
1299      }
1300  
1301      if (!is_null($toreturn)) {
1302          $toreturn = clone($toreturn);
1303      }
1304      return $toreturn;
1305  }
1306  
1307  /**
1308   * Get the list of categories.
1309   *
1310   * @param int $categoryid
1311   * @return array of question category ids of the category and all subcategories.
1312   */
1313  function question_categorylist($categoryid): array {
1314      global $DB;
1315  
1316      // Final list of category IDs.
1317      $categorylist = array();
1318  
1319      // A list of category IDs to check for any sub-categories.
1320      $subcategories = array($categoryid);
1321  
1322      while ($subcategories) {
1323          foreach ($subcategories as $subcategory) {
1324              // If anything from the temporary list was added already, then we have a loop.
1325              if (isset($categorylist[$subcategory])) {
1326                  throw new coding_exception("Category id=$subcategory is already on the list - loop of categories detected.");
1327              }
1328              $categorylist[$subcategory] = $subcategory;
1329          }
1330  
1331          list ($in, $params) = $DB->get_in_or_equal($subcategories);
1332  
1333          $subcategories = $DB->get_records_select_menu('question_categories', "parent $in", $params,
1334                                                      null, 'id,id AS id2');
1335      }
1336  
1337      return $categorylist;
1338  }
1339  
1340  /**
1341   * Get all parent categories of a given question category in decending order.
1342   * @param int $categoryid for which you want to find the parents.
1343   * @return array of question category ids of all parents categories.
1344   */
1345  function question_categorylist_parents(int $categoryid): array {
1346      global $DB;
1347      $parent = $DB->get_field('question_categories', 'parent', array('id' => $categoryid));
1348      if (!$parent) {
1349          return [];
1350      }
1351      $categorylist = [$parent];
1352      $currentid = $parent;
1353      while ($currentid) {
1354          $currentid = $DB->get_field('question_categories', 'parent', array('id' => $currentid));
1355          if ($currentid) {
1356              $categorylist[] = $currentid;
1357          }
1358      }
1359      // Present the list in decending order (the top category at the top).
1360      $categorylist = array_reverse($categorylist);
1361      return $categorylist;
1362  }
1363  
1364  // Import/Export Functions.
1365  
1366  /**
1367   * Get list of available import or export formats
1368   * @param string $type 'import' if import list, otherwise export list assumed
1369   * @return array sorted list of import/export formats available
1370   */
1371  function get_import_export_formats($type): array {
1372      global $CFG;
1373      require_once($CFG->dirroot . '/question/format.php');
1374  
1375      $formatclasses = core_component::get_plugin_list_with_class('qformat', '', 'format.php');
1376  
1377      $fileformatname = array();
1378      foreach ($formatclasses as $component => $formatclass) {
1379  
1380          $format = new $formatclass();
1381          if ($type == 'import') {
1382              $provided = $format->provide_import();
1383          } else {
1384              $provided = $format->provide_export();
1385          }
1386  
1387          if ($provided) {
1388              list($notused, $fileformat) = explode('_', $component, 2);
1389              $fileformatnames[$fileformat] = get_string('pluginname', $component);
1390          }
1391      }
1392  
1393      core_collator::asort($fileformatnames);
1394      return $fileformatnames;
1395  }
1396  
1397  
1398  /**
1399   * Create a reasonable default file name for exporting questions from a particular
1400   * category.
1401   * @param object $course the course the questions are in.
1402   * @param object $category the question category.
1403   * @return string the filename.
1404   */
1405  function question_default_export_filename($course, $category): string {
1406      // We build a string that is an appropriate name (questions) from the lang pack,
1407      // then the corse shortname, then the question category name, then a timestamp.
1408  
1409      $base = clean_filename(get_string('exportfilename', 'question'));
1410  
1411      $dateformat = str_replace(' ', '_', get_string('exportnameformat', 'question'));
1412      $timestamp = clean_filename(userdate(time(), $dateformat, 99, false));
1413  
1414      $shortname = clean_filename($course->shortname);
1415      if ($shortname == '' || $shortname == '_' ) {
1416          $shortname = $course->id;
1417      }
1418  
1419      $categoryname = clean_filename(format_string($category->name));
1420  
1421      return "{$base}-{$shortname}-{$categoryname}-{$timestamp}";
1422  }
1423  
1424  /**
1425   * Check capability on category.
1426   *
1427   * @param int|stdClass|question_definition $questionorid object or id.
1428   *      If an object is passed, it should include ->contextid and ->createdby.
1429   * @param string $cap 'add', 'edit', 'view', 'use', 'move' or 'tag'.
1430   * @param int $notused no longer used.
1431   * @return bool this user has the capability $cap for this question $question?
1432   */
1433  function question_has_capability_on($questionorid, $cap, $notused = -1): bool {
1434      global $USER, $DB;
1435  
1436      if (is_numeric($questionorid)) {
1437          $questionid = (int)$questionorid;
1438      } else if (is_object($questionorid)) {
1439          // All we really need in this function is the contextid and author of the question.
1440          // We won't bother fetching other details of the question if these 2 fields are provided.
1441          if (isset($questionorid->contextid) && isset($questionorid->createdby)) {
1442              $question = $questionorid;
1443          } else if (!empty($questionorid->id)) {
1444              $questionid = $questionorid->id;
1445          }
1446      }
1447  
1448      // At this point, either $question or $questionid is expected to be set.
1449      if (isset($questionid)) {
1450          try {
1451              $question = question_bank::load_question_data($questionid);
1452          } catch (Exception $e) {
1453              // Let's log the exception for future debugging,
1454              // but not during Behat, or we can't test these cases.
1455              if (!defined('BEHAT_SITE_RUNNING')) {
1456                  debugging($e->getMessage(), DEBUG_NORMAL, $e->getTrace());
1457              }
1458  
1459              $sql = 'SELECT q.id,
1460                             q.createdby,
1461                             qc.contextid
1462                        FROM {question} q
1463                        JOIN {question_versions} qv
1464                          ON qv.questionid = q.id
1465                        JOIN {question_bank_entries} qbe
1466                          ON qbe.id = qv.questionbankentryid
1467                        JOIN {question_categories} qc
1468                          ON qc.id = qbe.questioncategoryid
1469                       WHERE q.id = :id';
1470  
1471              // Well, at least we tried. Seems that we really have to read from DB.
1472              $question = $DB->get_record_sql($sql, ['id' => $questionid]);
1473          }
1474      }
1475  
1476      if (!isset($question)) {
1477          throw new coding_exception('$questionorid parameter needs to be an integer or an object.');
1478      }
1479  
1480      $context = context::instance_by_id($question->contextid);
1481  
1482      // These are existing questions capabilities that are set per category.
1483      // Each of these has a 'mine' and 'all' version that is appended to the capability name.
1484      $capabilitieswithallandmine = ['edit' => 1, 'view' => 1, 'use' => 1, 'move' => 1, 'tag' => 1, 'comment' => 1];
1485  
1486      if (!isset($capabilitieswithallandmine[$cap])) {
1487          return has_capability('moodle/question:' . $cap, $context);
1488      } else {
1489          return has_capability('moodle/question:' . $cap . 'all', $context) ||
1490              ($question->createdby == $USER->id && has_capability('moodle/question:' . $cap . 'mine', $context));
1491      }
1492  }
1493  
1494  /**
1495   * Require capability on question.
1496   *
1497   * @param int|stdClass|question_definition $question object or id.
1498   *      If an object is passed, it should include ->contextid and ->createdby.
1499   * @param string $cap 'add', 'edit', 'view', 'use', 'move' or 'tag'.
1500   * @return bool true if the user has the capability. Throws exception if not.
1501   */
1502  function question_require_capability_on($question, $cap): bool {
1503      if (!question_has_capability_on($question, $cap)) {
1504          throw new moodle_exception('nopermissions', '', '', $cap);
1505      }
1506      return true;
1507  }
1508  
1509  /**
1510   * Gets the question edit url.
1511   *
1512   * @param object $context a context
1513   * @return string|bool A URL for editing questions in this context.
1514   */
1515  function question_edit_url($context) {
1516      global $CFG, $SITE;
1517      if (!has_any_capability(question_get_question_capabilities(), $context)) {
1518          return false;
1519      }
1520      $baseurl = $CFG->wwwroot . '/question/edit.php?';
1521      $defaultcategory = question_get_default_category($context->id);
1522      if ($defaultcategory) {
1523          $baseurl .= 'cat=' . $defaultcategory->id . ',' . $context->id . '&amp;';
1524      }
1525      switch ($context->contextlevel) {
1526          case CONTEXT_SYSTEM:
1527              return $baseurl . 'courseid=' . $SITE->id;
1528          case CONTEXT_COURSECAT:
1529              // This is nasty, becuase we can only edit questions in a course
1530              // context at the moment, so for now we just return false.
1531              return false;
1532          case CONTEXT_COURSE:
1533              return $baseurl . 'courseid=' . $context->instanceid;
1534          case CONTEXT_MODULE:
1535              return $baseurl . 'cmid=' . $context->instanceid;
1536      }
1537  
1538  }
1539  
1540  /**
1541   * Adds question bank setting links to the given navigation node if caps are met
1542   * and loads the navigation from the plugins.
1543   * Qbank plugins can extend the navigation_plugin_base and add their own navigation node,
1544   * this method will help to autoload those nodes in the question bank navigation.
1545   *
1546   * @param navigation_node $navigationnode The navigation node to add the question branch to
1547   * @param object $context
1548   * @param string $baseurl the url of the base where the api is implemented from
1549   * @return navigation_node Returns the question branch that was added
1550   */
1551  function question_extend_settings_navigation(navigation_node $navigationnode, $context, $baseurl = '/question/edit.php') {
1552      global $PAGE;
1553  
1554      if ($context->contextlevel == CONTEXT_COURSE) {
1555          $params = ['courseid' => $context->instanceid];
1556      } else if ($context->contextlevel == CONTEXT_MODULE) {
1557          $params = ['cmid' => $context->instanceid];
1558      } else {
1559          return;
1560      }
1561  
1562      if (($cat = $PAGE->url->param('cat')) && preg_match('~\d+,\d+~', $cat)) {
1563          $params['cat'] = $cat;
1564      }
1565  
1566      $questionnode = $navigationnode->add(get_string('questionbank', 'question'),
1567              new moodle_url($baseurl, $params), navigation_node::TYPE_CONTAINER, null, 'questionbank');
1568  
1569      $corenavigations = [
1570              'questions' => [
1571                      'title' => get_string('questions', 'question'),
1572                      'url' => new moodle_url($baseurl)
1573              ],
1574              'categories' => [],
1575              'import' => [],
1576              'export' => []
1577      ];
1578  
1579      $plugins = \core_component::get_plugin_list_with_class('qbank', 'plugin_feature', 'plugin_feature.php');
1580      foreach ($plugins as $componentname => $plugin) {
1581          $pluginentrypoint = new $plugin();
1582          $pluginentrypointobject = $pluginentrypoint->get_navigation_node();
1583          // Don't need the plugins without navigation node.
1584          if ($pluginentrypointobject === null) {
1585              unset($plugins[$componentname]);
1586              continue;
1587          }
1588          foreach ($corenavigations as $key => $corenavigation) {
1589              if ($pluginentrypointobject->get_navigation_key() === $key) {
1590                  unset($plugins[$componentname]);
1591                  if (!\core\plugininfo\qbank::is_plugin_enabled($componentname)) {
1592                      unset($corenavigations[$key]);
1593                      break;
1594                  }
1595                  $corenavigations[$key] = [
1596                      'title' => $pluginentrypointobject->get_navigation_title(),
1597                      'url'   => $pluginentrypointobject->get_navigation_url()
1598                  ];
1599              }
1600          }
1601      }
1602  
1603      // Mitigate the risk of regression.
1604      foreach ($corenavigations as $node => $corenavigation) {
1605          if (empty($corenavigation)) {
1606              unset($corenavigations[$node]);
1607          }
1608      }
1609  
1610      // Community/additional plugins have navigation node.
1611      $pluginnavigations = [];
1612      foreach ($plugins as $componentname => $plugin) {
1613          $pluginentrypoint = new $plugin();
1614          $pluginentrypointobject = $pluginentrypoint->get_navigation_node();
1615          // Don't need the plugins without navigation node.
1616          if ($pluginentrypointobject === null || !\core\plugininfo\qbank::is_plugin_enabled($componentname)) {
1617              unset($plugins[$componentname]);
1618              continue;
1619          }
1620          $pluginnavigations[$pluginentrypointobject->get_navigation_key()] = [
1621              'title' => $pluginentrypointobject->get_navigation_title(),
1622              'url'   => $pluginentrypointobject->get_navigation_url(),
1623              'capabilities' => $pluginentrypointobject->get_navigation_capabilities()
1624          ];
1625      }
1626  
1627      $contexts = new core_question\local\bank\question_edit_contexts($context);
1628      foreach ($corenavigations as $key => $corenavigation) {
1629          if ($contexts->have_one_edit_tab_cap($key)) {
1630              $questionnode->add($corenavigation['title'], new moodle_url(
1631                      $corenavigation['url'], $params), navigation_node::TYPE_SETTING, null, $key);
1632          }
1633      }
1634  
1635      foreach ($pluginnavigations as $key => $pluginnavigation) {
1636          if (is_array($pluginnavigation['capabilities'])) {
1637              if (!$contexts->have_one_cap($pluginnavigation['capabilities'])) {
1638                  continue;
1639              }
1640          }
1641          $questionnode->add($pluginnavigation['title'], new moodle_url(
1642                  $pluginnavigation['url'], $params), navigation_node::TYPE_SETTING, null, $key);
1643      }
1644  
1645      return $questionnode;
1646  }
1647  
1648  /**
1649   * Get the array of capabilities for question.
1650   *
1651   * @return array all the capabilities that relate to accessing particular questions.
1652   */
1653  function question_get_question_capabilities(): array {
1654      return [
1655          'moodle/question:add',
1656          'moodle/question:editmine',
1657          'moodle/question:editall',
1658          'moodle/question:viewmine',
1659          'moodle/question:viewall',
1660          'moodle/question:usemine',
1661          'moodle/question:useall',
1662          'moodle/question:movemine',
1663          'moodle/question:moveall',
1664          'moodle/question:tagmine',
1665          'moodle/question:tagall',
1666          'moodle/question:commentmine',
1667          'moodle/question:commentall',
1668      ];
1669  }
1670  
1671  /**
1672   * Get the question bank caps.
1673   *
1674   * @return array all the question bank capabilities.
1675   */
1676  function question_get_all_capabilities(): array {
1677      $caps = question_get_question_capabilities();
1678      $caps[] = 'moodle/question:managecategory';
1679      $caps[] = 'moodle/question:flag';
1680      return $caps;
1681  }
1682  
1683  /**
1684   * Helps call file_rewrite_pluginfile_urls with the right parameters.
1685   *
1686   * @package  core_question
1687   * @category files
1688   * @param string $text text being processed
1689   * @param string $file the php script used to serve files
1690   * @param int $contextid context ID
1691   * @param string $component component
1692   * @param string $filearea filearea
1693   * @param array $ids other IDs will be used to check file permission
1694   * @param int $itemid item ID
1695   * @param array $options options
1696   * @return string
1697   */
1698  function question_rewrite_question_urls($text, $file, $contextid, $component, $filearea,
1699                                          array $ids, $itemid, array $options=null): string {
1700  
1701      $idsstr = '';
1702      if (!empty($ids)) {
1703          $idsstr .= implode('/', $ids);
1704      }
1705      if ($itemid !== null) {
1706          $idsstr .= '/' . $itemid;
1707      }
1708      return file_rewrite_pluginfile_urls($text, $file, $contextid, $component,
1709              $filearea, $idsstr, $options);
1710  }
1711  
1712  /**
1713   * Rewrite the PLUGINFILE urls in part of the content of a question, for use when
1714   * viewing the question outside an attempt (for example, in the question bank
1715   * listing or in the quiz statistics report).
1716   *
1717   * @param string $text the question text.
1718   * @param int $questionid the question id.
1719   * @param int $filecontextid the context id of the question being displayed.
1720   * @param string $filecomponent the component that owns the file area.
1721   * @param string $filearea the file area name.
1722   * @param int|null $itemid the file's itemid
1723   * @param int $previewcontextid the context id where the preview is being displayed.
1724   * @param string $previewcomponent component responsible for displaying the preview.
1725   * @param array $options text and file options ('forcehttps'=>false)
1726   * @return string $questiontext with URLs rewritten.
1727   */
1728  function question_rewrite_question_preview_urls($text, $questionid, $filecontextid, $filecomponent, $filearea, $itemid,
1729                                                  $previewcontextid, $previewcomponent, $options = null): string {
1730  
1731      $path = "preview/$previewcontextid/$previewcomponent/$questionid";
1732      if ($itemid) {
1733          $path .= '/' . $itemid;
1734      }
1735  
1736      return file_rewrite_pluginfile_urls($text, 'pluginfile.php', $filecontextid,
1737              $filecomponent, $filearea, $path, $options);
1738  }
1739  
1740  /**
1741   * Called by pluginfile.php to serve files related to the 'question' core
1742   * component and for files belonging to qtypes.
1743   *
1744   * For files that relate to questions in a question_attempt, then we delegate to
1745   * a function in the component that owns the attempt (for example in the quiz,
1746   * or in core question preview) to get necessary inforation.
1747   *
1748   * (Note that, at the moment, all question file areas relate to questions in
1749   * attempts, so the If at the start of the last paragraph is always true.)
1750   *
1751   * Does not return, either calls send_file_not_found(); or serves the file.
1752   *
1753   * @category files
1754   * @param stdClass $course course settings object
1755   * @param stdClass $context context object
1756   * @param string $component the name of the component we are serving files for.
1757   * @param string $filearea the name of the file area.
1758   * @param array $args the remaining bits of the file path.
1759   * @param bool $forcedownload whether the user must be forced to download the file.
1760   * @param array $options additional options affecting the file serving
1761   * @return array|bool
1762   */
1763  function question_pluginfile($course, $context, $component, $filearea, $args, $forcedownload, $options = []) {
1764      global $DB, $CFG;
1765  
1766      // Special case, sending a question bank export.
1767      if ($filearea === 'export') {
1768          list($context, $course, $cm) = get_context_info_array($context->id);
1769          require_login($course, false, $cm);
1770  
1771          require_once($CFG->dirroot . '/question/editlib.php');
1772          $contexts = new core_question\local\bank\question_edit_contexts($context);
1773          // Check export capability.
1774          $contexts->require_one_edit_tab_cap('export');
1775          $categoryid = (int)array_shift($args);
1776          $format      = array_shift($args);
1777          $cattofile   = array_shift($args);
1778          $contexttofile = array_shift($args);
1779          $filename    = array_shift($args);
1780  
1781          // Load parent class for import/export.
1782          require_once($CFG->dirroot . '/question/format.php');
1783          require_once($CFG->dirroot . '/question/editlib.php');
1784          require_once($CFG->dirroot . '/question/format/' . $format . '/format.php');
1785  
1786          $classname = 'qformat_' . $format;
1787          if (!class_exists($classname)) {
1788              send_file_not_found();
1789          }
1790  
1791          $qformat = new $classname();
1792  
1793          if (!$category = $DB->get_record('question_categories', array('id' => $categoryid))) {
1794              send_file_not_found();
1795          }
1796  
1797          $qformat->setCategory($category);
1798          $qformat->setContexts($contexts->having_one_edit_tab_cap('export'));
1799          $qformat->setCourse($course);
1800  
1801          if ($cattofile == 'withcategories') {
1802              $qformat->setCattofile(true);
1803          } else {
1804              $qformat->setCattofile(false);
1805          }
1806  
1807          if ($contexttofile == 'withcontexts') {
1808              $qformat->setContexttofile(true);
1809          } else {
1810              $qformat->setContexttofile(false);
1811          }
1812  
1813          if (!$qformat->exportpreprocess()) {
1814              send_file_not_found();
1815              throw new moodle_exception('exporterror', 'question', $thispageurl->out());
1816          }
1817  
1818          // Export data to moodle file pool.
1819          if (!$content = $qformat->exportprocess()) {
1820              send_file_not_found();
1821          }
1822  
1823          send_file($content, $filename, 0, 0, true, true, $qformat->mime_type());
1824      }
1825  
1826      // Normal case, a file belonging to a question.
1827      $qubaidorpreview = array_shift($args);
1828  
1829      // Two sub-cases: 1. A question being previewed outside an attempt/usage.
1830      if ($qubaidorpreview === 'preview') {
1831          $previewcontextid = (int)array_shift($args);
1832          $previewcomponent = array_shift($args);
1833          $questionid = (int) array_shift($args);
1834          $previewcontext = context_helper::instance_by_id($previewcontextid);
1835  
1836          $result = component_callback($previewcomponent, 'question_preview_pluginfile', array(
1837                  $previewcontext, $questionid,
1838                  $context, $component, $filearea, $args,
1839                  $forcedownload, $options), 'callbackmissing');
1840  
1841          if ($result === 'callbackmissing') {
1842              throw new coding_exception("Component {$previewcomponent} does not define the callback " .
1843                      "{$previewcomponent}_question_preview_pluginfile callback. " .
1844                      "Which is required if you are using question_rewrite_question_preview_urls.", DEBUG_DEVELOPER);
1845          }
1846  
1847          send_file_not_found();
1848      }
1849  
1850      // 2. A question being attempted in the normal way.
1851      $qubaid = (int)$qubaidorpreview;
1852      $slot = (int)array_shift($args);
1853  
1854      $module = $DB->get_field('question_usages', 'component',
1855              array('id' => $qubaid));
1856      if (!$module) {
1857          send_file_not_found();
1858      }
1859  
1860      if ($module === 'core_question_preview') {
1861          return qbank_previewquestion\helper::question_preview_question_pluginfile($course, $context,
1862                  $component, $filearea, $qubaid, $slot, $args, $forcedownload, $options);
1863  
1864      } else {
1865          $dir = core_component::get_component_directory($module);
1866          if (!file_exists("$dir/lib.php")) {
1867              send_file_not_found();
1868          }
1869          include_once("$dir/lib.php");
1870  
1871          $filefunction = $module . '_question_pluginfile';
1872          if (function_exists($filefunction)) {
1873              $filefunction($course, $context, $component, $filearea, $qubaid, $slot,
1874                  $args, $forcedownload, $options);
1875          }
1876  
1877          // Okay, we're here so lets check for function without 'mod_'.
1878          if (strpos($module, 'mod_') === 0) {
1879              $filefunctionold  = substr($module, 4) . '_question_pluginfile';
1880              if (function_exists($filefunctionold)) {
1881                  $filefunctionold($course, $context, $component, $filearea, $qubaid, $slot,
1882                      $args, $forcedownload, $options);
1883              }
1884          }
1885  
1886          send_file_not_found();
1887      }
1888  }
1889  
1890  /**
1891   * Serve questiontext files in the question text when they are displayed in this report.
1892   *
1893   * @param context $previewcontext the context in which the preview is happening.
1894   * @param int $questionid the question id.
1895   * @param context $filecontext the file (question) context.
1896   * @param string $filecomponent the component the file belongs to.
1897   * @param string $filearea the file area.
1898   * @param array $args remaining file args.
1899   * @param bool $forcedownload
1900   * @param array $options additional options affecting the file serving.
1901   */
1902  function core_question_question_preview_pluginfile($previewcontext, $questionid, $filecontext, $filecomponent,
1903                                                      $filearea, $args, $forcedownload, $options = []): void {
1904      global $DB;
1905      $sql = 'SELECT q.*,
1906                     qc.contextid
1907                FROM {question} q
1908                JOIN {question_versions} qv
1909                  ON qv.questionid = q.id
1910                JOIN {question_bank_entries} qbe
1911                  ON qbe.id = qv.questionbankentryid
1912                JOIN {question_categories} qc
1913                  ON qc.id = qbe.questioncategoryid
1914               WHERE q.id = :id
1915                 AND qc.contextid = :contextid';
1916  
1917      // Verify that contextid matches the question.
1918      $question = $DB->get_record_sql($sql, ['id' => $questionid, 'contextid' => $filecontext->id], MUST_EXIST);
1919  
1920      // Check the capability.
1921      list($context, $course, $cm) = get_context_info_array($previewcontext->id);
1922      require_login($course, false, $cm);
1923  
1924      question_require_capability_on($question, 'use');
1925  
1926      $fs = get_file_storage();
1927      $relativepath = implode('/', $args);
1928      $fullpath = "/{$filecontext->id}/{$filecomponent}/{$filearea}/{$relativepath}";
1929      if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
1930          send_file_not_found();
1931      }
1932  
1933      send_stored_file($file, 0, 0, $forcedownload, $options);
1934  }
1935  
1936  /**
1937   * Return a list of page types
1938   * @param string $pagetype current page type
1939   * @param stdClass $parentcontext Block's parent context
1940   * @param stdClass $currentcontext Current context of block
1941   * @return array
1942   */
1943  function question_page_type_list($pagetype, $parentcontext, $currentcontext): array {
1944      global $CFG;
1945      $types = [
1946          'question-*' => get_string('page-question-x', 'question'),
1947          'question-edit' => get_string('page-question-edit', 'question'),
1948          'question-category' => get_string('page-question-category', 'question'),
1949          'question-export' => get_string('page-question-export', 'question'),
1950          'question-import' => get_string('page-question-import', 'question')
1951      ];
1952      if ($currentcontext->contextlevel == CONTEXT_COURSE) {
1953          require_once($CFG->dirroot . '/course/lib.php');
1954          return array_merge(course_page_type_list($pagetype, $parentcontext, $currentcontext), $types);
1955      } else {
1956          return $types;
1957      }
1958  }
1959  
1960  /**
1961   * Does an activity module use the question bank?
1962   *
1963   * @param string $modname The name of the module (without mod_ prefix).
1964   * @return bool true if the module uses questions.
1965   */
1966  function question_module_uses_questions($modname): bool {
1967      if (plugin_supports('mod', $modname, FEATURE_USES_QUESTIONS)) {
1968          return true;
1969      }
1970  
1971      $component = 'mod_'.$modname;
1972      if (component_callback_exists($component, 'question_pluginfile')) {
1973          debugging("{$component} uses questions but doesn't declare FEATURE_USES_QUESTIONS", DEBUG_DEVELOPER);
1974          return true;
1975      }
1976  
1977      return false;
1978  }
1979  
1980  /**
1981   * If $oldidnumber ends in some digits then return the next available idnumber of the same form.
1982   *
1983   * So idnum -> null (no digits at the end) idnum0099 -> idnum0100 (if that is unused,
1984   * else whichever of idnum0101, idnume0102, ... is unused. idnum9 -> idnum10.
1985   *
1986   * @param string|null $oldidnumber a question idnumber, or can be null.
1987   * @param int $categoryid a question category id.
1988   * @return string|null suggested new idnumber for a question in that category, or null if one cannot be found.
1989   */
1990  function core_question_find_next_unused_idnumber(?string $oldidnumber, int $categoryid): ?string {
1991      global $DB;
1992  
1993      // The the old idnumber is not of the right form, bail now.
1994      if (!preg_match('~\d+$~', $oldidnumber, $matches)) {
1995          return null;
1996      }
1997  
1998      // Find all used idnumbers in one DB query.
1999      $usedidnumbers = $DB->get_records_select_menu('question_bank_entries', 'questioncategoryid = ? AND idnumber IS NOT NULL',
2000              [$categoryid], '', 'idnumber, 1');
2001  
2002      // Find the next unused idnumber.
2003      $numberbit = 'X' . $matches[0]; // Need a string here so PHP does not do '0001' + 1 = 2.
2004      $stem = substr($oldidnumber, 0, -strlen($matches[0]));
2005      do {
2006  
2007          // If we have got to something9999, insert an extra digit before incrementing.
2008          if (preg_match('~^(.*[^0-9])(9+)$~', $numberbit, $matches)) {
2009              $numberbit = $matches[1] . '0' . $matches[2];
2010          }
2011          $numberbit++;
2012          $newidnumber = $stem . substr($numberbit, 1);
2013      } while (isset($usedidnumbers[$newidnumber]));
2014  
2015      return (string) $newidnumber;
2016  }
2017  
2018  /**
2019   * Get the question_bank_entry object given a question id.
2020   *
2021   * @param int $questionid Question id.
2022   * @return false|mixed
2023   * @throws dml_exception
2024   */
2025  function get_question_bank_entry(int $questionid): object {
2026      global $DB;
2027  
2028      $sql = "SELECT qbe.*
2029                FROM {question} q
2030                JOIN {question_versions} qv ON qv.questionid = q.id
2031                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
2032               WHERE q.id = :id";
2033  
2034      $qbankentry = $DB->get_record_sql($sql, ['id' => $questionid]);
2035  
2036      return $qbankentry;
2037  }
2038  
2039  /**
2040   * Get the question versions given a question id in a descending sort .
2041   *
2042   * @param int $questionid Question id.
2043   * @return array
2044   * @throws dml_exception
2045   */
2046  function get_question_version($questionid): array {
2047      global $DB;
2048  
2049      $version = $DB->get_records('question_versions', ['questionid' => $questionid]);
2050      krsort($version);
2051  
2052      return $version;
2053  }
2054  
2055  /**
2056   * Get the next version number to create base on a Question bank entry id.
2057   *
2058   * @param int $questionbankentryid Question bank entry id.
2059   * @return int next version number.
2060   * @throws dml_exception
2061   */
2062  function get_next_version(int $questionbankentryid): int {
2063      global $DB;
2064  
2065      $sql = "SELECT MAX(qv.version)
2066                FROM {question_versions} qv
2067                JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid
2068               WHERE qbe.id = :id";
2069  
2070      $nextversion = $DB->get_field_sql($sql, ['id' => $questionbankentryid]);
2071  
2072      if ($nextversion) {
2073          return (int)$nextversion + 1;
2074      }
2075  
2076      return 1;
2077  }
2078  
2079  /**
2080   * Checks if question is the latest version.
2081   *
2082   * @param string $version Question version to check.
2083   * @param string $questionbankentryid Entry to check against.
2084   * @return bool
2085   */
2086  function is_latest(string $version, string $questionbankentryid) : bool {
2087      global $DB;
2088  
2089      $sql = 'SELECT MAX(version) AS max
2090                    FROM {question_versions}
2091                   WHERE questionbankentryid = ?';
2092      $latestversion = $DB->get_record_sql($sql, [$questionbankentryid]);
2093  
2094      if (isset($latestversion->max)) {
2095          return ($version === $latestversion->max) ? true : false;
2096      }
2097      return false;
2098  }
2099  
2100  // Deprecated functions from Moodle 4.0.
2101  
2102  /**
2103   * Generate the URL for starting a new preview of a given question with the given options.
2104   * @param integer $questionid the question to preview.
2105   * @param string $preferredbehaviour the behaviour to use for the preview.
2106   * @param float $maxmark the maximum to mark the question out of.
2107   * @param question_display_options $displayoptions the display options to use.
2108   * @param int $variant the variant of the question to preview. If null, one will
2109   *      be picked randomly.
2110   * @param object $context context to run the preview in (affects things like
2111   *      filter settings, theme, lang, etc.) Defaults to $PAGE->context.
2112   * @return moodle_url the URL.
2113   * @deprecated since Moodle 4.0
2114   * @see qbank_previewquestion\helper::question_preview_url()
2115   * @todo Final deprecation on Moodle 4.4 MDL-72438
2116   */
2117  function question_preview_url($questionid, $preferredbehaviour = null,
2118                                $maxmark = null, $displayoptions = null, $variant = null, $context = null) {
2119      debugging('Function question_preview_url() has been deprecated and moved to qbank_previewquestion plugin,
2120      Please use qbank_previewquestion\previewquestion_helper::question_preview_url() instead.', DEBUG_DEVELOPER);
2121  
2122      return \qbank_previewquestion\helper::question_preview_url($questionid, $preferredbehaviour,
2123          $maxmark, $displayoptions, $variant, $context);
2124  }
2125  
2126  /**
2127   * Popup params for the question preview.
2128   *
2129   * @return array that can be passed as $params to the {@see popup_action()} constructor.
2130   * @deprecated since Moodle 4.0
2131   * @see qbank_previewquestion\previewquestion_helper::question_preview_popup_params()
2132   * @todo Final deprecation on Moodle 4.4 MDL-72438
2133   */
2134  function question_preview_popup_params() {
2135      debugging('Function question_preview_popup_params() has been deprecated and moved to qbank_previewquestion plugin,
2136      Please use qbank_previewquestion\previewquestion_helper::question_preview_popup_params() instead.', DEBUG_DEVELOPER);
2137  
2138      return \qbank_previewquestion\helper::question_preview_popup_params();
2139  }
2140  
2141  /**
2142   * Creates a stamp that uniquely identifies this version of the question
2143   *
2144   * In future we want this to use a hash of the question data to guarantee that
2145   * identical versions have the same version stamp.
2146   *
2147   * @param object $question
2148   * @return string A unique version stamp
2149   * @deprecated since Moodle 4.0
2150   * @todo Final deprecation on Moodle 4.4 MDL-72438
2151   */
2152  function question_hash($question) {
2153      debugging('Function question_hash() has been deprecated without replacement.', DEBUG_DEVELOPER);
2154      return make_unique_id_code();
2155  }
2156  
2157  /**
2158   * Create url for question export.
2159   *
2160   * @param int $contextid
2161   * @param int $categoryid
2162   * @param string $format
2163   * @param string $withcategories
2164   * @param string $withcontexts
2165   * @param string $filename
2166   * @return moodle_url export file url
2167   * @deprecated since Moodle 4.0 MDL-71573
2168   * @see qbank_exportquestions\exportquestions_helper
2169   * @todo Final deprecation on Moodle 4.4 MDL-72438
2170   */
2171  function question_make_export_url($contextid, $categoryid, $format, $withcategories,
2172                                    $withcontexts, $filename) {
2173      debugging('Function question_make_export_url() has been deprecated and moved to qbank_exportquestions plugin,
2174      Please use qbank_exportquestions\exportquestions_helper::question_make_export_url() instead.', DEBUG_DEVELOPER);
2175  
2176      return \qbank_exportquestions\exportquestions_helper::question_make_export_url($contextid, $categoryid, $format,
2177          $withcategories, $withcontexts, $filename);
2178  }
2179  
2180  /**
2181   * Get the URL to export a single question (exportone.php).
2182   *
2183   * @param stdClass|question_definition $question the question definition as obtained from
2184   *      question_bank::load_question_data() or question_bank::make_question().
2185   *      (Only ->id and ->contextid are used.)
2186   * @return moodle_url the requested URL.
2187   * @deprecated since Moodle 4.0
2188   * @see \qbank_exporttoxml\helper::question_get_export_single_question_url()
2189   * @todo Final deprecation on Moodle 4.4 MDL-72438
2190   */
2191  function question_get_export_single_question_url($question) {
2192      debugging('Function question_get_export_single_question_url() has been deprecated and moved to qbank_exporttoxml plugin,
2193       please use qbank_exporttoxml\helper::question_get_export_single_question_url() instead.', DEBUG_DEVELOPER);
2194      qbank_exporttoxml\helper::question_get_export_single_question_url($question);
2195  }
2196  
2197  /**
2198   * Remove stale questions from a category.
2199   *
2200   * While questions should not be left behind when they are not used any more,
2201   * it does happen, maybe via restore, or old logic, or uncovered scenarios. When
2202   * this happens, the users are unable to delete the question category unless
2203   * they move those stale questions to another one category, but to them the
2204   * category is empty as it does not contain anything. The purpose of this function
2205   * is to detect the questions that may have gone stale and remove them.
2206   *
2207   * You will typically use this prior to checking if the category contains questions.
2208   *
2209   * The stale questions (unused and hidden to the user) handled are:
2210   * - hidden questions
2211   * - random questions
2212   *
2213   * @param int $categoryid The category ID.
2214   * @deprecated since Moodle 4.0 MDL-71585
2215   * @see qbank_managecategories\helper
2216   * @todo Final deprecation on Moodle 4.4 MDL-72438
2217   */
2218  function question_remove_stale_questions_from_category($categoryid) {
2219      debugging('Function question_remove_stale_questions_from_category()
2220      has been deprecated and moved to qbank_managecategories plugin,
2221      Please use qbank_managecategories\helper::question_remove_stale_questions_from_category() instead.',
2222          DEBUG_DEVELOPER);
2223      \qbank_managecategories\helper::question_remove_stale_questions_from_category($categoryid);
2224  }
2225  
2226  /**
2227   * Private method, only for the use of add_indented_names().
2228   *
2229   * Recursively adds an indentedname field to each category, starting with the category
2230   * with id $id, and dealing with that category and all its children, and
2231   * return a new array, with those categories in the right order.
2232   *
2233   * @param array $categories an array of categories which has had childids
2234   *          fields added by flatten_category_tree(). Passed by reference for
2235   *          performance only. It is not modfied.
2236   * @param int $id the category to start the indenting process from.
2237   * @param int $depth the indent depth. Used in recursive calls.
2238   * @param int $nochildrenof
2239   * @return array a new array of categories, in the right order for the tree.
2240   * @deprecated since Moodle 4.0 MDL-71585
2241   * @see qbank_managecategories\helper
2242   * @todo Final deprecation on Moodle 4.4 MDL-72438
2243   */
2244  function flatten_category_tree(&$categories, $id, $depth = 0, $nochildrenof = -1) {
2245      debugging('Function flatten_category_tree() has been deprecated and moved to qbank_managecategories plugin,
2246      Please use qbank_managecategories\helper::flatten_category_tree() instead.', DEBUG_DEVELOPER);
2247      return \qbank_managecategories\helper::flatten_category_tree($categories, $id, $depth, $nochildrenof);
2248  }
2249  
2250  /**
2251   * Format categories into an indented list reflecting the tree structure.
2252   *
2253   * @param array $categories An array of category objects, for example from the.
2254   * @param int $nochildrenof
2255   * @return array The formatted list of categories.
2256   * @deprecated since Moodle 4.0 MDL-71585
2257   * @see qbank_managecategories\helper
2258   * @todo Final deprecation on Moodle 4.4 MDL-72438
2259   */
2260  function add_indented_names($categories, $nochildrenof = -1) {
2261      debugging('Function add_indented_names() has been deprecated and moved to qbank_managecategories plugin,
2262      Please use qbank_managecategories\helper::add_indented_names() instead.', DEBUG_DEVELOPER);
2263      return \qbank_managecategories\helper::add_indented_names($categories, $nochildrenof);
2264  }
2265  
2266  /**
2267   * Output a select menu of question categories.
2268   * Categories from this course and (optionally) published categories from other courses
2269   * are included. Optionally, only categories the current user may edit can be included.
2270   *
2271   * @param array $contexts
2272   * @param bool $top
2273   * @param int $currentcat
2274   * @param integer $selected optionally, the id of a category to be selected by
2275   *      default in the dropdown.
2276   * @param int $nochildrenof
2277   * @deprecated since Moodle 4.0 MDL-71585
2278   * @see qbank_managecategories\helper
2279   * @todo Final deprecation on Moodle 4.4 MDL-72438
2280   */
2281  function question_category_select_menu($contexts, $top = false, $currentcat = 0,
2282                                         $selected = "", $nochildrenof = -1) {
2283      debugging('Function question_category_select_menu() has been deprecated and moved to qbank_managecategories plugin,
2284      Please use qbank_managecategories\helper::question_category_select_menu() instead.', DEBUG_DEVELOPER);
2285      \qbank_managecategories\helper::question_category_select_menu($contexts, $top, $currentcat, $selected, $nochildrenof);
2286  }
2287  
2288  /**
2289   * Get all the category objects, including a count of the number of questions in that category,
2290   * for all the categories in the lists $contexts.
2291   *
2292   * @param mixed $contexts either a single contextid, or a comma-separated list of context ids.
2293   * @param string $sortorder used as the ORDER BY clause in the select statement.
2294   * @param bool $top Whether to return the top categories or not.
2295   * @return array of category objects.
2296   * @deprecated since Moodle 4.0 MDL-71585
2297   * @see qbank_managecategories\helper
2298   * @todo Final deprecation on Moodle 4.4 MDL-72438
2299   */
2300  function get_categories_for_contexts($contexts, $sortorder = 'parent, sortorder, name ASC', $top = false) {
2301      debugging('Function get_categories_for_contexts() has been deprecated and moved to qbank_managecategories plugin,
2302      Please use qbank_managecategories\helper::get_categories_for_contexts() instead.', DEBUG_DEVELOPER);
2303      return \qbank_managecategories\helper::get_categories_for_contexts($contexts, $sortorder, $top);
2304  }
2305  
2306  /**
2307   * Output an array of question categories.
2308   *
2309   * @param array $contexts The list of contexts.
2310   * @param bool $top Whether to return the top categories or not.
2311   * @param int $currentcat
2312   * @param bool $popupform
2313   * @param int $nochildrenof
2314   * @param boolean $escapecontextnames Whether the returned name of the thing is to be HTML escaped or not.
2315   * @return array
2316   * @deprecated since Moodle 4.0 MDL-71585
2317   * @see qbank_managecategories\helper
2318   * @todo Final deprecation on Moodle 4.4 MDL-72438
2319   */
2320  function question_category_options($contexts, $top = false, $currentcat = 0,
2321                                     $popupform = false, $nochildrenof = -1, $escapecontextnames = true) {
2322      debugging('Function question_category_options() has been deprecated and moved to qbank_managecategories plugin,
2323      Please use qbank_managecategories\helper::question_category_options() instead.', DEBUG_DEVELOPER);
2324      return \qbank_managecategories\helper::question_category_options($contexts, $top, $currentcat,
2325          $popupform, $nochildrenof, $escapecontextnames);
2326  }
2327  
2328  /**
2329   * Add context in categories key.
2330   *
2331   * @param array $categories The list of categories.
2332   * @return array
2333   * @deprecated since Moodle 4.0 MDL-71585
2334   * @see qbank_managecategories\helper
2335   * @todo Final deprecation on Moodle 4.4 MDL-72438
2336   */
2337  function question_add_context_in_key($categories) {
2338      debugging('Function question_add_context_in_key() has been deprecated and moved to qbank_managecategories plugin,
2339      Please use qbank_managecategories\helper::question_add_context_in_key() instead.', DEBUG_DEVELOPER);
2340      return \qbank_managecategories\helper::question_add_context_in_key($categories);
2341  }
2342  
2343  /**
2344   * Finds top categories in the given categories hierarchy and replace their name with a proper localised string.
2345   *
2346   * @param array $categories An array of question categories.
2347   * @param boolean $escape Whether the returned name of the thing is to be HTML escaped or not.
2348   * @return array The same question category list given to the function, with the top category names being translated.
2349   * @deprecated since Moodle 4.0 MDL-71585
2350   * @see qbank_managecategories\helper
2351   * @todo Final deprecation on Moodle 4.4 MDL-72438
2352   */
2353  function question_fix_top_names($categories, $escape = true) {
2354      debugging('Function question_fix_top_names() has been deprecated and moved to qbank_managecategories plugin,
2355      Please use qbank_managecategories\helper::question_fix_top_names() instead.', DEBUG_DEVELOPER);
2356      return \qbank_managecategories\helper::question_fix_top_names($categories, $escape);
2357  }