[Summary view]

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

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Question type class for the random question type.
  19   *
  20   * @package    qtype
  21   * @subpackage random
  22   * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  require_once($CFG->dirroot . '/question/type/questiontypebase.php');
  30  
  31  
  32  /**
  33   * The random question type.
  34   *
  35   * This question type does not have a question definition class, nor any
  36   * renderers. When you load a question of this type, it actually loads a
  37   * question chosen randomly from a particular category in the question bank.
  38   *
  39   * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  40   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  41   */
  42  class qtype_random extends question_type {
  43      /** @var string comma-separated list of qytpe names not to select, can be used in SQL. */
  44      protected $excludedqtypes = null;
  45  
  46      /** @var string comma-separated list of manually graded qytpe names, can be used in SQL. */
  47      protected $manualqtypes = null;
  48  
  49      /**
  50       * Cache of availabe question ids from a particular category.
  51       * @var array two-dimensional array. The first key is a category id, the
  52       * second key is wether subcategories should be included.
  53       */
  54      private $availablequestionsbycategory = array();
  55  
  56      public function menu_name() {
  57          // Don't include this question type in the 'add new question' menu.
  58          return false;
  59      }
  60  
  61      public function is_manual_graded() {
  62          return true;
  63      }
  64  
  65      public function is_usable_by_random() {
  66          return false;
  67      }
  68  
  69      public function is_question_manual_graded($question, $otherquestionsinuse) {
  70          global $DB;
  71          // We take our best shot at working whether a particular question is manually
  72          // graded follows: We look to see if any of the questions that this random
  73          // question might select if of a manually graded type. If a category contains
  74          // a mixture of manual and non-manual questions, and if all the attempts so
  75          // far selected non-manual ones, this will give the wrong answer, but we
  76          // don't care. Even so, this is an expensive calculation!
  77          $this->init_qtype_lists();
  78          if (!$this->manualqtypes) {
  79              return false;
  80          }
  81          if ($question->questiontext) {
  82              $categorylist = question_categorylist($question->category);
  83          } else {
  84              $categorylist = array($question->category);
  85          }
  86          list($qcsql, $qcparams) = $DB->get_in_or_equal($categorylist);
  87          // TODO use in_or_equal for $otherquestionsinuse and $this->manualqtypes.
  88          return $DB->record_exists_select('question',
  89                  "category {$qcsql}
  90                       AND parent = 0
  91                       AND hidden = 0
  92                       AND id NOT IN ($otherquestionsinuse)
  93                       AND qtype IN ($this->manualqtypes)", $qcparams);
  94      }
  95  
  96      /**
  97       * This method needs to be called before the ->excludedqtypes and
  98       *      ->manualqtypes fields can be used.
  99       */
 100      protected function init_qtype_lists() {
 101          if (!is_null($this->excludedqtypes)) {
 102              return; // Already done.
 103          }
 104          $excludedqtypes = array();
 105          $manualqtypes = array();
 106          foreach (question_bank::get_all_qtypes() as $qtype) {
 107              $quotedname = "'" . $qtype->name() . "'";
 108              if (!$qtype->is_usable_by_random()) {
 109                  $excludedqtypes[] = $quotedname;
 110              } else if ($qtype->is_manual_graded()) {
 111                  $manualqtypes[] = $quotedname;
 112              }
 113          }
 114          $this->excludedqtypes = implode(',', $excludedqtypes);
 115          $this->manualqtypes = implode(',', $manualqtypes);
 116      }
 117  
 118      public function get_question_options($question) {
 119          parent::get_question_options($question);
 120          return true;
 121      }
 122  
 123      /**
 124       * Random questions always get a question name that is Random (cateogryname).
 125       * This function is a centralised place to calculate that, given the category.
 126       * @param stdClass $category the category this question picks from. (Only ->name is used.)
 127       * @param bool $includesubcategories whether this question also picks from subcategories.
 128       * @param string[] $tagnames Name of tags this question picks from.
 129       * @return string the name this question should have.
 130       */
 131      public function question_name($category, $includesubcategories, $tagnames = []) {
 132          $categoryname = '';
 133          if ($category->parent && $includesubcategories) {
 134              $stringid = 'randomqplusname';
 135              $categoryname = shorten_text($category->name, 100);
 136          } else if ($category->parent) {
 137              $stringid = 'randomqname';
 138              $categoryname = shorten_text($category->name, 100);
 139          } else if ($includesubcategories) {
 140              $context = context::instance_by_id($category->contextid);
 141  
 142              switch ($context->contextlevel) {
 143                  case CONTEXT_MODULE:
 144                      $stringid = 'randomqplusnamemodule';
 145                      break;
 146                  case CONTEXT_COURSE:
 147                      $stringid = 'randomqplusnamecourse';
 148                      break;
 149                  case CONTEXT_COURSECAT:
 150                      $stringid = 'randomqplusnamecoursecat';
 151                      $categoryname = shorten_text($context->get_context_name(false), 100);
 152                      break;
 153                  case CONTEXT_SYSTEM:
 154                      $stringid = 'randomqplusnamesystem';
 155                      break;
 156                  default: // Impossible.
 157              }
 158          } else {
 159              // No question will ever be selected. So, let's warn the teacher.
 160              $stringid = 'randomqnamefromtop';
 161          }
 162  
 163          if ($tagnames) {
 164              $stringid .= 'tags';
 165              $a = new stdClass();
 166              if ($categoryname) {
 167                  $a->category = $categoryname;
 168              }
 169              $a->tags = implode(', ', array_map(function($tagname) {
 170                  return explode(',', $tagname)[1];
 171              }, $tagnames));
 172          } else {
 173              $a = $categoryname ? : null;
 174          }
 175  
 176          $name = get_string($stringid, 'qtype_random', $a);
 177  
 178          return shorten_text($name, 255);
 179      }
 180  
 181      protected function set_selected_question_name($question, $randomname) {
 182          $a = new stdClass();
 183          $a->randomname = $randomname;
 184          $a->questionname = $question->name;
 185          $question->name = get_string('selectedby', 'qtype_random', $a);
 186      }
 187  
 188      public function save_question($question, $form) {
 189          global $DB;
 190  
 191          $form->name = '';
 192          list($category) = explode(',', $form->category);
 193  
 194          if (!$form->includesubcategories) {
 195              if ($DB->record_exists('question_categories', ['id' => $category, 'parent' => 0])) {
 196                  // The chosen category is a top category.
 197                  $form->includesubcategories = true;
 198              }
 199          }
 200  
 201          $form->tags = array();
 202  
 203          if (empty($form->fromtags)) {
 204              $form->fromtags = array();
 205          }
 206  
 207          $form->questiontext = array(
 208              'text'   => $form->includesubcategories ? '1' : '0',
 209              'format' => 0
 210          );
 211  
 212          // Name is not a required field for random questions, but
 213          // parent::save_question Assumes that it is.
 214          return parent::save_question($question, $form);
 215      }
 216  
 217      public function save_question_options($question) {
 218          global $DB;
 219  
 220          // No options, as such, but we set the parent field to the question's
 221          // own id. Setting the parent field has the effect of hiding this
 222          // question in various places.
 223          $updateobject = new stdClass();
 224          $updateobject->id = $question->id;
 225          $updateobject->parent = $question->id;
 226  
 227          // We also force the question name to be 'Random (categoryname)'.
 228          $category = $DB->get_record('question_categories',
 229                  array('id' => $question->category), '*', MUST_EXIST);
 230          $updateobject->name = $this->question_name($category, $question->includesubcategories, $question->fromtags);
 231          return $DB->update_record('question', $updateobject);
 232      }
 233  
 234      /**
 235       * During unit tests we need to be able to reset all caches so that each new test starts in a known state.
 236       * Intended for use only for testing. This is a stop gap until we start using the MUC caching api here.
 237       * You need to call this before every test that loads one or more random questions.
 238       */
 239      public function clear_caches_before_testing() {
 240          $this->availablequestionsbycategory = array();
 241      }
 242  
 243      /**
 244       * Get all the usable questions from a particular question category.
 245       *
 246       * @param int $categoryid the id of a question category.
 247       * @param bool whether to include questions from subcategories.
 248       * @param string $questionsinuse comma-separated list of question ids to
 249       *      exclude from consideration.
 250       * @return array of question records.
 251       */
 252      public function get_available_questions_from_category($categoryid, $subcategories) {
 253          if (isset($this->availablequestionsbycategory[$categoryid][$subcategories])) {
 254              return $this->availablequestionsbycategory[$categoryid][$subcategories];
 255          }
 256  
 257          $this->init_qtype_lists();
 258          if ($subcategories) {
 259              $categoryids = question_categorylist($categoryid);
 260          } else {
 261              $categoryids = array($categoryid);
 262          }
 263  
 264          $questionids = question_bank::get_finder()->get_questions_from_categories(
 265                  $categoryids, 'qtype NOT IN (' . $this->excludedqtypes . ')');
 266          $this->availablequestionsbycategory[$categoryid][$subcategories] = $questionids;
 267          return $questionids;
 268      }
 269  
 270      public function make_question($questiondata) {
 271          return $this->choose_other_question($questiondata, array());
 272      }
 273  
 274      /**
 275       * Load the definition of another question picked randomly by this question.
 276       * @param object       $questiondata the data defining a random question.
 277       * @param array        $excludedquestions of question ids. We will no pick any question whose id is in this list.
 278       * @param bool         $allowshuffle      if false, then any shuffle option on the selected quetsion is disabled.
 279       * @param null|integer $forcequestionid   if not null then force the picking of question with id $forcequestionid.
 280       * @throws coding_exception
 281       * @return question_definition|null the definition of the question that was
 282       *      selected, or null if no suitable question could be found.
 283       */
 284      public function choose_other_question($questiondata, $excludedquestions, $allowshuffle = true, $forcequestionid = null) {
 285          $available = $this->get_available_questions_from_category($questiondata->category,
 286                  !empty($questiondata->questiontext));
 287          shuffle($available);
 288  
 289          if ($forcequestionid !== null) {
 290              $forcedquestionkey = array_search($forcequestionid, $available);
 291              if ($forcedquestionkey !== false) {
 292                  unset($available[$forcedquestionkey]);
 293                  array_unshift($available, $forcequestionid);
 294              } else {
 295                  throw new coding_exception('thisquestionidisnotavailable', $forcequestionid);
 296              }
 297          }
 298  
 299          foreach ($available as $questionid) {
 300              if (in_array($questionid, $excludedquestions)) {
 301                  continue;
 302              }
 303  
 304              $question = question_bank::load_question($questionid, $allowshuffle);
 305              $this->set_selected_question_name($question, $questiondata->name);
 306              return $question;
 307          }
 308          return null;
 309      }
 310  
 311      public function get_random_guess_score($questiondata) {
 312          return null;
 313      }
 314  }