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Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.

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

   1  <?php
   2  
   3  // This file is part of Moodle - http://moodle.org/
   4  //
   5  // Moodle is free software: you can redistribute it and/or modify
   6  // it under the terms of the GNU General Public License as published by
   7  // the Free Software Foundation, either version 3 of the License, or
   8  // (at your option) any later version.
   9  //
  10  // Moodle is distributed in the hope that it will be useful,
  11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  // GNU General Public License for more details.
  14  //
  15  // You should have received a copy of the GNU General Public License
  16  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17  
  18  /**
  19   * Local library file for Lesson.  These are non-standard functions that are used
  20   * only by Lesson.
  21   *
  22   * @package mod_lesson
  23   * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
  24   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or late
  25   **/
  26  
  27  /** Make sure this isn't being directly accessed */
  28  defined('MOODLE_INTERNAL') || die();
  29  
  30  /** Include the files that are required by this module */
  31  require_once($CFG->dirroot.'/course/moodleform_mod.php');
  32  require_once($CFG->dirroot . '/mod/lesson/lib.php');
  33  require_once($CFG->libdir . '/filelib.php');
  34  
  35  /** This page */
  36  define('LESSON_THISPAGE', 0);
  37  /** Next page -> any page not seen before */
  38  define("LESSON_UNSEENPAGE", 1);
  39  /** Next page -> any page not answered correctly */
  40  define("LESSON_UNANSWEREDPAGE", 2);
  41  /** Jump to Next Page */
  42  define("LESSON_NEXTPAGE", -1);
  43  /** End of Lesson */
  44  define("LESSON_EOL", -9);
  45  /** Jump to an unseen page within a branch and end of branch or end of lesson */
  46  define("LESSON_UNSEENBRANCHPAGE", -50);
  47  /** Jump to Previous Page */
  48  define("LESSON_PREVIOUSPAGE", -40);
  49  /** Jump to a random page within a branch and end of branch or end of lesson */
  50  define("LESSON_RANDOMPAGE", -60);
  51  /** Jump to a random Branch */
  52  define("LESSON_RANDOMBRANCH", -70);
  53  /** Cluster Jump */
  54  define("LESSON_CLUSTERJUMP", -80);
  55  /** Undefined */
  56  define("LESSON_UNDEFINED", -99);
  57  
  58  /** LESSON_MAX_EVENT_LENGTH = 432000 ; 5 days maximum */
  59  define("LESSON_MAX_EVENT_LENGTH", "432000");
  60  
  61  /** Answer format is HTML */
  62  define("LESSON_ANSWER_HTML", "HTML");
  63  
  64  /** Placeholder answer for all other answers. */
  65  define("LESSON_OTHER_ANSWERS", "@#wronganswer#@");
  66  
  67  //////////////////////////////////////////////////////////////////////////////////////
  68  /// Any other lesson functions go here.  Each of them must have a name that
  69  /// starts with lesson_
  70  
  71  /**
  72   * Checks to see if a LESSON_CLUSTERJUMP or
  73   * a LESSON_UNSEENBRANCHPAGE is used in a lesson.
  74   *
  75   * This function is only executed when a teacher is
  76   * checking the navigation for a lesson.
  77   *
  78   * @param stdClass $lesson Id of the lesson that is to be checked.
  79   * @return boolean True or false.
  80   **/
  81  function lesson_display_teacher_warning($lesson) {
  82      global $DB;
  83  
  84      // get all of the lesson answers
  85      $params = array ("lessonid" => $lesson->id);
  86      if (!$lessonanswers = $DB->get_records_select("lesson_answers", "lessonid = :lessonid", $params)) {
  87          // no answers, then not using cluster or unseen
  88          return false;
  89      }
  90      // just check for the first one that fulfills the requirements
  91      foreach ($lessonanswers as $lessonanswer) {
  92          if ($lessonanswer->jumpto == LESSON_CLUSTERJUMP || $lessonanswer->jumpto == LESSON_UNSEENBRANCHPAGE) {
  93              return true;
  94          }
  95      }
  96  
  97      // if no answers use either of the two jumps
  98      return false;
  99  }
 100  
 101  /**
 102   * Interprets the LESSON_UNSEENBRANCHPAGE jump.
 103   *
 104   * will return the pageid of a random unseen page that is within a branch
 105   *
 106   * @param lesson $lesson
 107   * @param int $userid Id of the user.
 108   * @param int $pageid Id of the page from which we are jumping.
 109   * @return int Id of the next page.
 110   **/
 111  function lesson_unseen_question_jump($lesson, $user, $pageid) {
 112      global $DB;
 113  
 114      // get the number of retakes
 115      if (!$retakes = $DB->count_records("lesson_grades", array("lessonid"=>$lesson->id, "userid"=>$user))) {
 116          $retakes = 0;
 117      }
 118  
 119      // get all the lesson_attempts aka what the user has seen
 120      if ($viewedpages = $DB->get_records("lesson_attempts", array("lessonid"=>$lesson->id, "userid"=>$user, "retry"=>$retakes), "timeseen DESC")) {
 121          foreach($viewedpages as $viewed) {
 122              $seenpages[] = $viewed->pageid;
 123          }
 124      } else {
 125          $seenpages = array();
 126      }
 127  
 128      // get the lesson pages
 129      $lessonpages = $lesson->load_all_pages();
 130  
 131      if ($pageid == LESSON_UNSEENBRANCHPAGE) {  // this only happens when a student leaves in the middle of an unseen question within a branch series
 132          $pageid = $seenpages[0];  // just change the pageid to the last page viewed inside the branch table
 133      }
 134  
 135      // go up the pages till branch table
 136      while ($pageid != 0) { // this condition should never be satisfied... only happens if there are no branch tables above this page
 137          if ($lessonpages[$pageid]->qtype == LESSON_PAGE_BRANCHTABLE) {
 138              break;
 139          }
 140          $pageid = $lessonpages[$pageid]->prevpageid;
 141      }
 142  
 143      $pagesinbranch = $lesson->get_sub_pages_of($pageid, array(LESSON_PAGE_BRANCHTABLE, LESSON_PAGE_ENDOFBRANCH));
 144  
 145      // this foreach loop stores all the pages that are within the branch table but are not in the $seenpages array
 146      $unseen = array();
 147      foreach($pagesinbranch as $page) {
 148          if (!in_array($page->id, $seenpages)) {
 149              $unseen[] = $page->id;
 150          }
 151      }
 152  
 153      if(count($unseen) == 0) {
 154          if(isset($pagesinbranch)) {
 155              $temp = end($pagesinbranch);
 156              $nextpage = $temp->nextpageid; // they have seen all the pages in the branch, so go to EOB/next branch table/EOL
 157          } else {
 158              // there are no pages inside the branch, so return the next page
 159              $nextpage = $lessonpages[$pageid]->nextpageid;
 160          }
 161          if ($nextpage == 0) {
 162              return LESSON_EOL;
 163          } else {
 164              return $nextpage;
 165          }
 166      } else {
 167          return $unseen[rand(0, count($unseen)-1)];  // returns a random page id for the next page
 168      }
 169  }
 170  
 171  /**
 172   * Handles the unseen branch table jump.
 173   *
 174   * @param lesson $lesson
 175   * @param int $userid User id.
 176   * @return int Will return the page id of a branch table or end of lesson
 177   **/
 178  function lesson_unseen_branch_jump($lesson, $userid) {
 179      global $DB;
 180  
 181      if (!$retakes = $DB->count_records("lesson_grades", array("lessonid"=>$lesson->id, "userid"=>$userid))) {
 182          $retakes = 0;
 183      }
 184  
 185      if (!$seenbranches = $lesson->get_content_pages_viewed($retakes, $userid, 'timeseen DESC')) {
 186          throw new \moodle_exception('cannotfindrecords', 'lesson');
 187      }
 188  
 189      // get the lesson pages
 190      $lessonpages = $lesson->load_all_pages();
 191  
 192      // this loads all the viewed branch tables into $seen until it finds the branch table with the flag
 193      // which is the branch table that starts the unseenbranch function
 194      $seen = array();
 195      foreach ($seenbranches as $seenbranch) {
 196          if (!$seenbranch->flag) {
 197              $seen[$seenbranch->pageid] = $seenbranch->pageid;
 198          } else {
 199              $start = $seenbranch->pageid;
 200              break;
 201          }
 202      }
 203      // this function searches through the lesson pages to find all the branch tables
 204      // that follow the flagged branch table
 205      $pageid = $lessonpages[$start]->nextpageid; // move down from the flagged branch table
 206      $branchtables = array();
 207      while ($pageid != 0) {  // grab all of the branch table till eol
 208          if ($lessonpages[$pageid]->qtype == LESSON_PAGE_BRANCHTABLE) {
 209              $branchtables[] = $lessonpages[$pageid]->id;
 210          }
 211          $pageid = $lessonpages[$pageid]->nextpageid;
 212      }
 213      $unseen = array();
 214      foreach ($branchtables as $branchtable) {
 215          // load all of the unseen branch tables into unseen
 216          if (!array_key_exists($branchtable, $seen)) {
 217              $unseen[] = $branchtable;
 218          }
 219      }
 220      if (count($unseen) > 0) {
 221          return $unseen[rand(0, count($unseen)-1)];  // returns a random page id for the next page
 222      } else {
 223          return LESSON_EOL;  // has viewed all of the branch tables
 224      }
 225  }
 226  
 227  /**
 228   * Handles the random jump between a branch table and end of branch or end of lesson (LESSON_RANDOMPAGE).
 229   *
 230   * @param lesson $lesson
 231   * @param int $pageid The id of the page that we are jumping from (?)
 232   * @return int The pageid of a random page that is within a branch table
 233   **/
 234  function lesson_random_question_jump($lesson, $pageid) {
 235      global $DB;
 236  
 237      // get the lesson pages
 238      $params = array ("lessonid" => $lesson->id);
 239      if (!$lessonpages = $DB->get_records_select("lesson_pages", "lessonid = :lessonid", $params)) {
 240          throw new \moodle_exception('cannotfindpages', 'lesson');
 241      }
 242  
 243      // go up the pages till branch table
 244      while ($pageid != 0) { // this condition should never be satisfied... only happens if there are no branch tables above this page
 245  
 246          if ($lessonpages[$pageid]->qtype == LESSON_PAGE_BRANCHTABLE) {
 247              break;
 248          }
 249          $pageid = $lessonpages[$pageid]->prevpageid;
 250      }
 251  
 252      // get the pages within the branch
 253      $pagesinbranch = $lesson->get_sub_pages_of($pageid, array(LESSON_PAGE_BRANCHTABLE, LESSON_PAGE_ENDOFBRANCH));
 254  
 255      if(count($pagesinbranch) == 0) {
 256          // there are no pages inside the branch, so return the next page
 257          return $lessonpages[$pageid]->nextpageid;
 258      } else {
 259          return $pagesinbranch[rand(0, count($pagesinbranch)-1)]->id;  // returns a random page id for the next page
 260      }
 261  }
 262  
 263  /**
 264   * Calculates a user's grade for a lesson.
 265   *
 266   * @param object $lesson The lesson that the user is taking.
 267   * @param int $retries The attempt number.
 268   * @param int $userid Id of the user (optional, default current user).
 269   * @return object { nquestions => number of questions answered
 270                      attempts => number of question attempts
 271                      total => max points possible
 272                      earned => points earned by student
 273                      grade => calculated percentage grade
 274                      nmanual => number of manually graded questions
 275                      manualpoints => point value for manually graded questions }
 276   */
 277  function lesson_grade($lesson, $ntries, $userid = 0) {
 278      global $USER, $DB;
 279  
 280      if (empty($userid)) {
 281          $userid = $USER->id;
 282      }
 283  
 284      // Zero out everything
 285      $ncorrect     = 0;
 286      $nviewed      = 0;
 287      $score        = 0;
 288      $nmanual      = 0;
 289      $manualpoints = 0;
 290      $thegrade     = 0;
 291      $nquestions   = 0;
 292      $total        = 0;
 293      $earned       = 0;
 294  
 295      $params = array ("lessonid" => $lesson->id, "userid" => $userid, "retry" => $ntries);
 296      if ($useranswers = $DB->get_records_select("lesson_attempts",  "lessonid = :lessonid AND
 297              userid = :userid AND retry = :retry", $params, "timeseen")) {
 298          // group each try with its page
 299          $attemptset = array();
 300          foreach ($useranswers as $useranswer) {
 301              $attemptset[$useranswer->pageid][] = $useranswer;
 302          }
 303  
 304          if (!empty($lesson->maxattempts)) {
 305              // Drop all attempts that go beyond max attempts for the lesson.
 306              foreach ($attemptset as $key => $set) {
 307                  $attemptset[$key] = array_slice($set, 0, $lesson->maxattempts);
 308              }
 309          }
 310  
 311          // get only the pages and their answers that the user answered
 312          list($usql, $parameters) = $DB->get_in_or_equal(array_keys($attemptset));
 313          array_unshift($parameters, $lesson->id);
 314          $pages = $DB->get_records_select("lesson_pages", "lessonid = ? AND id $usql", $parameters);
 315          $answers = $DB->get_records_select("lesson_answers", "lessonid = ? AND pageid $usql", $parameters);
 316  
 317          // Number of pages answered
 318          $nquestions = count($pages);
 319  
 320          foreach ($attemptset as $attempts) {
 321              $page = lesson_page::load($pages[end($attempts)->pageid], $lesson);
 322              if ($lesson->custom) {
 323                  $attempt = end($attempts);
 324                  // If essay question, handle it, otherwise add to score
 325                  if ($page->requires_manual_grading()) {
 326                      $useranswerobj = unserialize_object($attempt->useranswer);
 327                      if (isset($useranswerobj->score)) {
 328                          $earned += $useranswerobj->score;
 329                      }
 330                      $nmanual++;
 331                      $manualpoints += $answers[$attempt->answerid]->score;
 332                  } else if (!empty($attempt->answerid)) {
 333                      $earned += $page->earned_score($answers, $attempt);
 334                  }
 335              } else {
 336                  foreach ($attempts as $attempt) {
 337                      $earned += $attempt->correct;
 338                  }
 339                  $attempt = end($attempts); // doesn't matter which one
 340                  // If essay question, increase numbers
 341                  if ($page->requires_manual_grading()) {
 342                      $nmanual++;
 343                      $manualpoints++;
 344                  }
 345              }
 346              // Number of times answered
 347              $nviewed += count($attempts);
 348          }
 349  
 350          if ($lesson->custom) {
 351              $bestscores = array();
 352              // Find the highest possible score per page to get our total
 353              foreach ($answers as $answer) {
 354                  if(!isset($bestscores[$answer->pageid])) {
 355                      $bestscores[$answer->pageid] = $answer->score;
 356                  } else if ($bestscores[$answer->pageid] < $answer->score) {
 357                      $bestscores[$answer->pageid] = $answer->score;
 358                  }
 359              }
 360              $total = array_sum($bestscores);
 361          } else {
 362              // Check to make sure the student has answered the minimum questions
 363              if ($lesson->minquestions and $nquestions < $lesson->minquestions) {
 364                  // Nope, increase number viewed by the amount of unanswered questions
 365                  $total =  $nviewed + ($lesson->minquestions - $nquestions);
 366              } else {
 367                  $total = $nviewed;
 368              }
 369          }
 370      }
 371  
 372      if ($total) { // not zero
 373          $thegrade = round(100 * $earned / $total, 5);
 374      }
 375  
 376      // Build the grade information object
 377      $gradeinfo               = new stdClass;
 378      $gradeinfo->nquestions   = $nquestions;
 379      $gradeinfo->attempts     = $nviewed;
 380      $gradeinfo->total        = $total;
 381      $gradeinfo->earned       = $earned;
 382      $gradeinfo->grade        = $thegrade;
 383      $gradeinfo->nmanual      = $nmanual;
 384      $gradeinfo->manualpoints = $manualpoints;
 385  
 386      return $gradeinfo;
 387  }
 388  
 389  /**
 390   * Determines if a user can view the left menu.  The determining factor
 391   * is whether a user has a grade greater than or equal to the lesson setting
 392   * of displayleftif
 393   *
 394   * @param object $lesson Lesson object of the current lesson
 395   * @return boolean 0 if the user cannot see, or $lesson->displayleft to keep displayleft unchanged
 396   **/
 397  function lesson_displayleftif($lesson) {
 398      global $CFG, $USER, $DB;
 399  
 400      if (!empty($lesson->displayleftif)) {
 401          // get the current user's max grade for this lesson
 402          $params = array ("userid" => $USER->id, "lessonid" => $lesson->id);
 403          if ($maxgrade = $DB->get_record_sql('SELECT userid, MAX(grade) AS maxgrade FROM {lesson_grades} WHERE userid = :userid AND lessonid = :lessonid GROUP BY userid', $params)) {
 404              if ($maxgrade->maxgrade < $lesson->displayleftif) {
 405                  return 0;  // turn off the displayleft
 406              }
 407          } else {
 408              return 0; // no grades
 409          }
 410      }
 411  
 412      // if we get to here, keep the original state of displayleft lesson setting
 413      return $lesson->displayleft;
 414  }
 415  
 416  /**
 417   *
 418   * @param $cm
 419   * @param $lesson
 420   * @param $page
 421   * @return unknown_type
 422   */
 423  function lesson_add_fake_blocks($page, $cm, $lesson, $timer = null) {
 424      $bc = lesson_menu_block_contents($cm->id, $lesson);
 425      if (!empty($bc)) {
 426          $regions = $page->blocks->get_regions();
 427          $firstregion = reset($regions);
 428          $page->blocks->add_fake_block($bc, $firstregion);
 429      }
 430  
 431      $bc = lesson_mediafile_block_contents($cm->id, $lesson);
 432      if (!empty($bc)) {
 433          $page->blocks->add_fake_block($bc, $page->blocks->get_default_region());
 434      }
 435  
 436      if (!empty($timer)) {
 437          $bc = lesson_clock_block_contents($cm->id, $lesson, $timer, $page);
 438          if (!empty($bc)) {
 439              $page->blocks->add_fake_block($bc, $page->blocks->get_default_region());
 440          }
 441      }
 442  }
 443  
 444  /**
 445   * If there is a media file associated with this
 446   * lesson, return a block_contents that displays it.
 447   *
 448   * @param int $cmid Course Module ID for this lesson
 449   * @param object $lesson Full lesson record object
 450   * @return block_contents
 451   **/
 452  function lesson_mediafile_block_contents($cmid, $lesson) {
 453      global $OUTPUT;
 454      if (empty($lesson->mediafile)) {
 455          return null;
 456      }
 457  
 458      $options = array();
 459      $options['menubar'] = 0;
 460      $options['location'] = 0;
 461      $options['left'] = 5;
 462      $options['top'] = 5;
 463      $options['scrollbars'] = 1;
 464      $options['resizable'] = 1;
 465      $options['width'] = $lesson->mediawidth;
 466      $options['height'] = $lesson->mediaheight;
 467  
 468      $link = new moodle_url('/mod/lesson/mediafile.php?id='.$cmid);
 469      $action = new popup_action('click', $link, 'lessonmediafile', $options);
 470      $content = $OUTPUT->action_link($link, get_string('mediafilepopup', 'lesson'), $action, array('title'=>get_string('mediafilepopup', 'lesson')));
 471  
 472      $bc = new block_contents();
 473      $bc->title = get_string('linkedmedia', 'lesson');
 474      $bc->attributes['class'] = 'mediafile block';
 475      $bc->content = $content;
 476  
 477      return $bc;
 478  }
 479  
 480  /**
 481   * If a timed lesson and not a teacher, then
 482   * return a block_contents containing the clock.
 483   *
 484   * @param int $cmid Course Module ID for this lesson
 485   * @param object $lesson Full lesson record object
 486   * @param object $timer Full timer record object
 487   * @return block_contents
 488   **/
 489  function lesson_clock_block_contents($cmid, $lesson, $timer, $page) {
 490      // Display for timed lessons and for students only
 491      $context = context_module::instance($cmid);
 492      if ($lesson->timelimit == 0 || has_capability('mod/lesson:manage', $context)) {
 493          return null;
 494      }
 495  
 496      $content = '<div id="lesson-timer">';
 497      $content .=  $lesson->time_remaining($timer->starttime);
 498      $content .= '</div>';
 499  
 500      $clocksettings = array('starttime' => $timer->starttime, 'servertime' => time(), 'testlength' => $lesson->timelimit);
 501      $page->requires->data_for_js('clocksettings', $clocksettings, true);
 502      $page->requires->strings_for_js(array('timeisup'), 'lesson');
 503      $page->requires->js('/mod/lesson/timer.js');
 504      $page->requires->js_init_call('show_clock');
 505  
 506      $bc = new block_contents();
 507      $bc->title = get_string('timeremaining', 'lesson');
 508      $bc->attributes['class'] = 'clock block';
 509      $bc->content = $content;
 510  
 511      return $bc;
 512  }
 513  
 514  /**
 515   * If left menu is turned on, then this will
 516   * print the menu in a block
 517   *
 518   * @param int $cmid Course Module ID for this lesson
 519   * @param lesson $lesson Full lesson record object
 520   * @return void
 521   **/
 522  function lesson_menu_block_contents($cmid, $lesson) {
 523      global $CFG, $DB;
 524  
 525      if (!$lesson->displayleft) {
 526          return null;
 527      }
 528  
 529      $pages = $lesson->load_all_pages();
 530      foreach ($pages as $page) {
 531          if ((int)$page->prevpageid === 0) {
 532              $pageid = $page->id;
 533              break;
 534          }
 535      }
 536      $currentpageid = optional_param('pageid', $pageid, PARAM_INT);
 537  
 538      if (!$pageid || !$pages) {
 539          return null;
 540      }
 541  
 542      $content = '<a href="#maincontent" class="accesshide">' .
 543          get_string('skip', 'lesson') .
 544          "</a>\n<div class=\"menuwrapper\">\n<ul>\n";
 545  
 546      while ($pageid != 0) {
 547          $page = $pages[$pageid];
 548  
 549          // Only process branch tables with display turned on
 550          if ($page->displayinmenublock && $page->display) {
 551              if ($page->id == $currentpageid) {
 552                  $content .= '<li class="selected">'.format_string($page->title,true)."</li>\n";
 553              } else {
 554                  $content .= "<li class=\"notselected\"><a href=\"$CFG->wwwroot/mod/lesson/view.php?id=$cmid&amp;pageid=$page->id\">".format_string($page->title,true)."</a></li>\n";
 555              }
 556  
 557          }
 558          $pageid = $page->nextpageid;
 559      }
 560      $content .= "</ul>\n</div>\n";
 561  
 562      $bc = new block_contents();
 563      $bc->title = get_string('lessonmenu', 'lesson');
 564      $bc->attributes['class'] = 'menu block';
 565      $bc->content = $content;
 566  
 567      return $bc;
 568  }
 569  
 570  /**
 571   * Adds header buttons to the page for the lesson
 572   *
 573   * @deprecated since Moodle 4.0 in favour of tertiary navigation.
 574   * @todo MDL-73545 This will be deleted in Moodle 4.4
 575   * @param object $cm
 576   * @param object $context
 577   * @param bool $extraeditbuttons
 578   * @param int $lessonpageid
 579   */
 580  function lesson_add_header_buttons($cm, $context, $extraeditbuttons=false, $lessonpageid=null) {
 581      global $CFG, $PAGE, $OUTPUT;
 582  
 583      debugging('lesson_add_header_buttons() is deprecated in favour of tertiary navigation.', DEBUG_DEVELOPER);
 584  
 585      if (has_capability('mod/lesson:edit', $context) && $extraeditbuttons) {
 586          if ($lessonpageid === null) {
 587              throw new \moodle_exception('invalidpageid', 'lesson');
 588          }
 589          if (!empty($lessonpageid) && $lessonpageid != LESSON_EOL) {
 590              $url = new moodle_url('/mod/lesson/editpage.php', array(
 591                  'id'       => $cm->id,
 592                  'pageid'   => $lessonpageid,
 593                  'edit'     => 1,
 594                  'returnto' => $PAGE->url->out_as_local_url(false)
 595              ));
 596              $PAGE->set_button($OUTPUT->single_button($url, get_string('editpagecontent', 'lesson')));
 597          }
 598      }
 599  }
 600  
 601  /**
 602   * This is a function used to detect media types and generate html code.
 603   *
 604   * @global object $CFG
 605   * @global object $PAGE
 606   * @param object $lesson
 607   * @param object $context
 608   * @return string $code the html code of media
 609   */
 610  function lesson_get_media_html($lesson, $context) {
 611      global $CFG, $PAGE, $OUTPUT;
 612      require_once("$CFG->libdir/resourcelib.php");
 613  
 614      // get the media file link
 615      if (strpos($lesson->mediafile, '://') !== false) {
 616          $url = new moodle_url($lesson->mediafile);
 617      } else {
 618          // the timemodified is used to prevent caching problems, instead of '/' we should better read from files table and use sortorder
 619          $url = moodle_url::make_pluginfile_url($context->id, 'mod_lesson', 'mediafile', $lesson->timemodified, '/', ltrim($lesson->mediafile, '/'));
 620      }
 621      $title = $lesson->mediafile;
 622  
 623      $clicktoopen = html_writer::link($url, get_string('download'));
 624  
 625      $mimetype = resourcelib_guess_url_mimetype($url);
 626  
 627      $extension = resourcelib_get_extension($url->out(false));
 628  
 629      $mediamanager = core_media_manager::instance($PAGE);
 630      $embedoptions = array(
 631          core_media_manager::OPTION_TRUSTED => true,
 632          core_media_manager::OPTION_BLOCK => true
 633      );
 634  
 635      // find the correct type and print it out
 636      if (in_array($mimetype, array('image/gif','image/jpeg','image/png'))) {  // It's an image
 637          $code = resourcelib_embed_image($url, $title);
 638  
 639      } else if ($mediamanager->can_embed_url($url, $embedoptions)) {
 640          // Media (audio/video) file.
 641          $code = $mediamanager->embed_url($url, $title, 0, 0, $embedoptions);
 642  
 643      } else {
 644          // anything else - just try object tag enlarged as much as possible
 645          $code = resourcelib_embed_general($url, $title, $clicktoopen, $mimetype);
 646      }
 647  
 648      return $code;
 649  }
 650  
 651  /**
 652   * Logic to happen when a/some group(s) has/have been deleted in a course.
 653   *
 654   * @param int $courseid The course ID.
 655   * @param int $groupid The group id if it is known
 656   * @return void
 657   */
 658  function lesson_process_group_deleted_in_course($courseid, $groupid = null) {
 659      global $DB;
 660  
 661      $params = array('courseid' => $courseid);
 662      if ($groupid) {
 663          $params['groupid'] = $groupid;
 664          // We just update the group that was deleted.
 665          $sql = "SELECT o.id, o.lessonid, o.groupid
 666                    FROM {lesson_overrides} o
 667                    JOIN {lesson} lesson ON lesson.id = o.lessonid
 668                   WHERE lesson.course = :courseid
 669                     AND o.groupid = :groupid";
 670      } else {
 671          // No groupid, we update all orphaned group overrides for all lessons in course.
 672          $sql = "SELECT o.id, o.lessonid, o.groupid
 673                    FROM {lesson_overrides} o
 674                    JOIN {lesson} lesson ON lesson.id = o.lessonid
 675               LEFT JOIN {groups} grp ON grp.id = o.groupid
 676                   WHERE lesson.course = :courseid
 677                     AND o.groupid IS NOT NULL
 678                     AND grp.id IS NULL";
 679      }
 680      $records = $DB->get_records_sql($sql, $params);
 681      if (!$records) {
 682          return; // Nothing to do.
 683      }
 684      $DB->delete_records_list('lesson_overrides', 'id', array_keys($records));
 685      $cache = cache::make('mod_lesson', 'overrides');
 686      foreach ($records as $record) {
 687          $cache->delete("{$record->lessonid}_g_{$record->groupid}");
 688      }
 689  }
 690  
 691  /**
 692   * Return the overview report table and data.
 693   *
 694   * @param  lesson $lesson       lesson instance
 695   * @param  mixed $currentgroup  false if not group used, 0 for all groups, group id (int) to filter by that groups
 696   * @return mixed false if there is no information otherwise html_table and stdClass with the table and data
 697   * @since  Moodle 3.3
 698   */
 699  function lesson_get_overview_report_table_and_data(lesson $lesson, $currentgroup) {
 700      global $DB, $CFG, $OUTPUT;
 701      require_once($CFG->dirroot . '/mod/lesson/pagetypes/branchtable.php');
 702  
 703      $context = $lesson->context;
 704      $cm = $lesson->cm;
 705      // Count the number of branch and question pages in this lesson.
 706      $branchcount = $DB->count_records('lesson_pages', array('lessonid' => $lesson->id, 'qtype' => LESSON_PAGE_BRANCHTABLE));
 707      $questioncount = ($DB->count_records('lesson_pages', array('lessonid' => $lesson->id)) - $branchcount);
 708  
 709      // Only load students if there attempts for this lesson.
 710      $attempts = $DB->record_exists('lesson_attempts', array('lessonid' => $lesson->id));
 711      $branches = $DB->record_exists('lesson_branch', array('lessonid' => $lesson->id));
 712      $timer = $DB->record_exists('lesson_timer', array('lessonid' => $lesson->id));
 713      if ($attempts or $branches or $timer) {
 714          list($esql, $params) = get_enrolled_sql($context, '', $currentgroup, true);
 715          list($sort, $sortparams) = users_order_by_sql('u');
 716  
 717          // TODO Does not support custom user profile fields (MDL-70456).
 718          $userfieldsapi = \core_user\fields::for_identity($context, false)->with_userpic();
 719          $ufields = $userfieldsapi->get_sql('u', false, '', '', false)->selects;
 720          $extrafields = $userfieldsapi->get_required_fields([\core_user\fields::PURPOSE_IDENTITY]);
 721  
 722          $params['a1lessonid'] = $lesson->id;
 723          $params['b1lessonid'] = $lesson->id;
 724          $params['c1lessonid'] = $lesson->id;
 725          $sql = "SELECT DISTINCT $ufields
 726                  FROM {user} u
 727                  JOIN (
 728                      SELECT userid, lessonid FROM {lesson_attempts} a1
 729                      WHERE a1.lessonid = :a1lessonid
 730                          UNION
 731                      SELECT userid, lessonid FROM {lesson_branch} b1
 732                      WHERE b1.lessonid = :b1lessonid
 733                          UNION
 734                      SELECT userid, lessonid FROM {lesson_timer} c1
 735                      WHERE c1.lessonid = :c1lessonid
 736                      ) a ON u.id = a.userid
 737                  JOIN ($esql) ue ON ue.id = a.userid
 738                  ORDER BY $sort";
 739  
 740          $students = $DB->get_recordset_sql($sql, $params);
 741          if (!$students->valid()) {
 742              $students->close();
 743              return array(false, false);
 744          }
 745      } else {
 746          return array(false, false);
 747      }
 748  
 749      if (! $grades = $DB->get_records('lesson_grades', array('lessonid' => $lesson->id), 'completed')) {
 750          $grades = array();
 751      }
 752  
 753      if (! $times = $DB->get_records('lesson_timer', array('lessonid' => $lesson->id), 'starttime')) {
 754          $times = array();
 755      }
 756  
 757      // Build an array for output.
 758      $studentdata = array();
 759  
 760      $attempts = $DB->get_recordset('lesson_attempts', array('lessonid' => $lesson->id), 'timeseen');
 761      foreach ($attempts as $attempt) {
 762          // if the user is not in the array or if the retry number is not in the sub array, add the data for that try.
 763          if (empty($studentdata[$attempt->userid]) || empty($studentdata[$attempt->userid][$attempt->retry])) {
 764              // restore/setup defaults
 765              $n = 0;
 766              $timestart = 0;
 767              $timeend = 0;
 768              $usergrade = null;
 769              $eol = 0;
 770  
 771              // search for the grade record for this try. if not there, the nulls defined above will be used.
 772              foreach($grades as $grade) {
 773                  // check to see if the grade matches the correct user
 774                  if ($grade->userid == $attempt->userid) {
 775                      // see if n is = to the retry
 776                      if ($n == $attempt->retry) {
 777                          // get grade info
 778                          $usergrade = round($grade->grade, 2); // round it here so we only have to do it once
 779                          break;
 780                      }
 781                      $n++; // if not equal, then increment n
 782                  }
 783              }
 784              $n = 0;
 785              // search for the time record for this try. if not there, the nulls defined above will be used.
 786              foreach($times as $time) {
 787                  // check to see if the grade matches the correct user
 788                  if ($time->userid == $attempt->userid) {
 789                      // see if n is = to the retry
 790                      if ($n == $attempt->retry) {
 791                          // get grade info
 792                          $timeend = $time->lessontime;
 793                          $timestart = $time->starttime;
 794                          $eol = $time->completed;
 795                          break;
 796                      }
 797                      $n++; // if not equal, then increment n
 798                  }
 799              }
 800  
 801              // build up the array.
 802              // this array represents each student and all of their tries at the lesson
 803              $studentdata[$attempt->userid][$attempt->retry] = array( "timestart" => $timestart,
 804                                                                      "timeend" => $timeend,
 805                                                                      "grade" => $usergrade,
 806                                                                      "end" => $eol,
 807                                                                      "try" => $attempt->retry,
 808                                                                      "userid" => $attempt->userid);
 809          }
 810      }
 811      $attempts->close();
 812  
 813      $branches = $DB->get_recordset('lesson_branch', array('lessonid' => $lesson->id), 'timeseen');
 814      foreach ($branches as $branch) {
 815          // If the user is not in the array or if the retry number is not in the sub array, add the data for that try.
 816          if (empty($studentdata[$branch->userid]) || empty($studentdata[$branch->userid][$branch->retry])) {
 817              // Restore/setup defaults.
 818              $n = 0;
 819              $timestart = 0;
 820              $timeend = 0;
 821              $usergrade = null;
 822              $eol = 0;
 823              // Search for the time record for this try. if not there, the nulls defined above will be used.
 824              foreach ($times as $time) {
 825                  // Check to see if the grade matches the correct user.
 826                  if ($time->userid == $branch->userid) {
 827                      // See if n is = to the retry.
 828                      if ($n == $branch->retry) {
 829                          // Get grade info.
 830                          $timeend = $time->lessontime;
 831                          $timestart = $time->starttime;
 832                          $eol = $time->completed;
 833                          break;
 834                      }
 835                      $n++; // If not equal, then increment n.
 836                  }
 837              }
 838  
 839              // Build up the array.
 840              // This array represents each student and all of their tries at the lesson.
 841              $studentdata[$branch->userid][$branch->retry] = array( "timestart" => $timestart,
 842                                                                      "timeend" => $timeend,
 843                                                                      "grade" => $usergrade,
 844                                                                      "end" => $eol,
 845                                                                      "try" => $branch->retry,
 846                                                                      "userid" => $branch->userid);
 847          }
 848      }
 849      $branches->close();
 850  
 851      // Need the same thing for timed entries that were not completed.
 852      foreach ($times as $time) {
 853          $endoflesson = $time->completed;
 854          // If the time start is the same with another record then we shouldn't be adding another item to this array.
 855          if (isset($studentdata[$time->userid])) {
 856              $foundmatch = false;
 857              $n = 0;
 858              foreach ($studentdata[$time->userid] as $key => $value) {
 859                  if ($value['timestart'] == $time->starttime) {
 860                      // Don't add this to the array.
 861                      $foundmatch = true;
 862                      break;
 863                  }
 864              }
 865              $n = count($studentdata[$time->userid]) + 1;
 866              if (!$foundmatch) {
 867                  // Add a record.
 868                  $studentdata[$time->userid][] = array(
 869                                  "timestart" => $time->starttime,
 870                                  "timeend" => $time->lessontime,
 871                                  "grade" => null,
 872                                  "end" => $endoflesson,
 873                                  "try" => $n,
 874                                  "userid" => $time->userid
 875                              );
 876              }
 877          } else {
 878              $studentdata[$time->userid][] = array(
 879                                  "timestart" => $time->starttime,
 880                                  "timeend" => $time->lessontime,
 881                                  "grade" => null,
 882                                  "end" => $endoflesson,
 883                                  "try" => 0,
 884                                  "userid" => $time->userid
 885                              );
 886          }
 887      }
 888  
 889      // To store all the data to be returned by the function.
 890      $data = new stdClass();
 891  
 892      // Determine if lesson should have a score.
 893      if ($branchcount > 0 AND $questioncount == 0) {
 894          // This lesson only contains content pages and is not graded.
 895          $data->lessonscored = false;
 896      } else {
 897          // This lesson is graded.
 898          $data->lessonscored = true;
 899      }
 900      // set all the stats variables
 901      $data->numofattempts = 0;
 902      $data->avescore      = 0;
 903      $data->avetime       = 0;
 904      $data->highscore     = null;
 905      $data->lowscore      = null;
 906      $data->hightime      = null;
 907      $data->lowtime       = null;
 908      $data->students      = array();
 909  
 910      $table = new html_table();
 911  
 912      $headers = [get_string('name')];
 913  
 914      foreach ($extrafields as $field) {
 915          $headers[] = \core_user\fields::get_display_name($field);
 916      }
 917  
 918      $caneditlesson = has_capability('mod/lesson:edit', $context);
 919      $attemptsheader = get_string('attempts', 'lesson');
 920      if ($caneditlesson) {
 921          $selectall = get_string('selectallattempts', 'lesson');
 922          $deselectall = get_string('deselectallattempts', 'lesson');
 923          // Build the select/deselect all control.
 924          $selectallid = 'selectall-attempts';
 925          $mastercheckbox = new \core\output\checkbox_toggleall('lesson-attempts', true, [
 926              'id' => $selectallid,
 927              'name' => $selectallid,
 928              'value' => 1,
 929              'label' => $selectall,
 930              'selectall' => $selectall,
 931              'deselectall' => $deselectall,
 932              'labelclasses' => 'form-check-label'
 933          ]);
 934          $attemptsheader = $OUTPUT->render($mastercheckbox);
 935      }
 936      $headers [] = $attemptsheader;
 937  
 938      // Set up the table object.
 939      if ($data->lessonscored) {
 940          $headers [] = get_string('highscore', 'lesson');
 941      }
 942  
 943      $colcount = count($headers);
 944  
 945      $table->head = $headers;
 946  
 947      $table->align = [];
 948      $table->align = array_pad($table->align, $colcount, 'center');
 949      $table->align[$colcount - 1] = 'left';
 950  
 951      if ($data->lessonscored) {
 952          $table->align[$colcount - 2] = 'left';
 953      }
 954  
 955      $table->attributes['class'] = 'table table-striped';
 956  
 957      // print out the $studentdata array
 958      // going through each student that has attempted the lesson, so, each student should have something to be displayed
 959      foreach ($students as $student) {
 960          // check to see if the student has attempts to print out
 961          if (array_key_exists($student->id, $studentdata)) {
 962              // set/reset some variables
 963              $attempts = array();
 964              $dataforstudent = new stdClass;
 965              $dataforstudent->attempts = array();
 966              // gather the data for each user attempt
 967              $bestgrade = 0;
 968  
 969              // $tries holds all the tries/retries a student has done
 970              $tries = $studentdata[$student->id];
 971              $studentname = fullname($student, true);
 972  
 973              foreach ($tries as $try) {
 974                  $dataforstudent->attempts[] = $try;
 975  
 976                  // Start to build up the checkbox and link.
 977                  $attempturlparams = [
 978                      'id' => $cm->id,
 979                      'action' => 'reportdetail',
 980                      'userid' => $try['userid'],
 981                      'try' => $try['try'],
 982                  ];
 983  
 984                  if ($try["grade"] !== null) { // if null then not done yet
 985                      // this is what the link does when the user has completed the try
 986                      $timetotake = $try["timeend"] - $try["timestart"];
 987  
 988                      if ($try["grade"] > $bestgrade) {
 989                          $bestgrade = $try["grade"];
 990                      }
 991  
 992                      $attemptdata = (object)[
 993                          'grade' => $try["grade"],
 994                          'timestart' => userdate($try["timestart"]),
 995                          'duration' => format_time($timetotake),
 996                      ];
 997                      $attemptlinkcontents = get_string('attemptinfowithgrade', 'lesson', $attemptdata);
 998  
 999                  } else {
1000                      if ($try["end"]) {
1001                          // User finished the lesson but has no grade. (Happens when there are only content pages).
1002                          $timetotake = $try["timeend"] - $try["timestart"];
1003                          $attemptdata = (object)[
1004                              'timestart' => userdate($try["timestart"]),
1005                              'duration' => format_time($timetotake),
1006                          ];
1007                          $attemptlinkcontents = get_string('attemptinfonograde', 'lesson', $attemptdata);
1008                      } else {
1009                          // This is what the link does/looks like when the user has not completed the attempt.
1010                          if ($try['timestart'] !== 0) {
1011                              // Teacher previews do not track time spent.
1012                              $attemptlinkcontents = get_string("notcompletedwithdate", "lesson", userdate($try["timestart"]));
1013                          } else {
1014                              $attemptlinkcontents = get_string("notcompleted", "lesson");
1015                          }
1016                          $timetotake = null;
1017                      }
1018                  }
1019                  $attempturl = new moodle_url('/mod/lesson/report.php', $attempturlparams);
1020                  $attemptlink = html_writer::link($attempturl, $attemptlinkcontents, ['class' => 'lesson-attempt-link']);
1021  
1022                  if ($caneditlesson) {
1023                      $attemptid = 'attempt-' . $try['userid'] . '-' . $try['try'];
1024                      $attemptname = 'attempts[' . $try['userid'] . '][' . $try['try'] . ']';
1025  
1026                      $checkbox = new \core\output\checkbox_toggleall('lesson-attempts', false, [
1027                          'id' => $attemptid,
1028                          'name' => $attemptname,
1029                          'label' => $attemptlink
1030                      ]);
1031                      $attemptlink = $OUTPUT->render($checkbox);
1032                  }
1033  
1034                  // build up the attempts array
1035                  $attempts[] = $attemptlink;
1036  
1037                  // Run these lines for the stats only if the user finnished the lesson.
1038                  if ($try["end"]) {
1039                      // User has completed the lesson.
1040                      $data->numofattempts++;
1041                      $data->avetime += $timetotake;
1042                      if ($timetotake > $data->hightime || $data->hightime == null) {
1043                          $data->hightime = $timetotake;
1044                      }
1045                      if ($timetotake < $data->lowtime || $data->lowtime == null) {
1046                          $data->lowtime = $timetotake;
1047                      }
1048                      if ($try["grade"] !== null) {
1049                          // The lesson was scored.
1050                          $data->avescore += $try["grade"];
1051                          if ($try["grade"] > $data->highscore || $data->highscore === null) {
1052                              $data->highscore = $try["grade"];
1053                          }
1054                          if ($try["grade"] < $data->lowscore || $data->lowscore === null) {
1055                              $data->lowscore = $try["grade"];
1056                          }
1057  
1058                      }
1059                  }
1060              }
1061              // get line breaks in after each attempt
1062              $attempts = implode("<br />\n", $attempts);
1063              $row = [$studentname];
1064  
1065              foreach ($extrafields as $field) {
1066                  $row[] = $student->$field;
1067              }
1068  
1069              $row[] = $attempts;
1070  
1071              if ($data->lessonscored) {
1072                  // Add the grade if the lesson is graded.
1073                  $row[] = $bestgrade."%";
1074              }
1075  
1076              $table->data[] = $row;
1077  
1078              // Add the student data.
1079              $dataforstudent->id = $student->id;
1080              $dataforstudent->fullname = $studentname;
1081              $dataforstudent->bestgrade = $bestgrade;
1082              $data->students[] = $dataforstudent;
1083          }
1084      }
1085      $students->close();
1086      if ($data->numofattempts > 0) {
1087          $data->avescore = $data->avescore / $data->numofattempts;
1088      }
1089  
1090      return array($table, $data);
1091  }
1092  
1093  /**
1094   * Return information about one user attempt (including answers)
1095   * @param  lesson $lesson  lesson instance
1096   * @param  int $userid     the user id
1097   * @param  int $attempt    the attempt number
1098   * @return array the user answers (array) and user data stats (object)
1099   * @since  Moodle 3.3
1100   */
1101  function lesson_get_user_detailed_report_data(lesson $lesson, $userid, $attempt) {
1102      global $DB;
1103  
1104      $context = $lesson->context;
1105      if (!empty($userid)) {
1106          // Apply overrides.
1107          $lesson->update_effective_access($userid);
1108      }
1109  
1110      $pageid = 0;
1111      $lessonpages = $lesson->load_all_pages();
1112      foreach ($lessonpages as $lessonpage) {
1113          if ($lessonpage->prevpageid == 0) {
1114              $pageid = $lessonpage->id;
1115          }
1116      }
1117  
1118      // now gather the stats into an object
1119      $firstpageid = $pageid;
1120      $pagestats = array();
1121      while ($pageid != 0) { // EOL
1122          $page = $lessonpages[$pageid];
1123          $params = array ("lessonid" => $lesson->id, "pageid" => $page->id);
1124          if ($allanswers = $DB->get_records_select("lesson_attempts", "lessonid = :lessonid AND pageid = :pageid", $params, "timeseen")) {
1125              // get them ready for processing
1126              $orderedanswers = array();
1127              foreach ($allanswers as $singleanswer) {
1128                  // ordering them like this, will help to find the single attempt record that we want to keep.
1129                  $orderedanswers[$singleanswer->userid][$singleanswer->retry][] = $singleanswer;
1130              }
1131              // this is foreach user and for each try for that user, keep one attempt record
1132              foreach ($orderedanswers as $orderedanswer) {
1133                  foreach($orderedanswer as $tries) {
1134                      $page->stats($pagestats, $tries);
1135                  }
1136              }
1137          } else {
1138              // no one answered yet...
1139          }
1140          //unset($orderedanswers);  initialized above now
1141          $pageid = $page->nextpageid;
1142      }
1143  
1144      $manager = lesson_page_type_manager::get($lesson);
1145      $qtypes = $manager->get_page_type_strings();
1146  
1147      $answerpages = array();
1148      $answerpage = "";
1149      $pageid = $firstpageid;
1150      // cycle through all the pages
1151      //  foreach page, add to the $answerpages[] array all the data that is needed
1152      //  from the question, the users attempt, and the statistics
1153      // grayout pages that the user did not answer and Branch, end of branch, cluster
1154      // and end of cluster pages
1155      while ($pageid != 0) { // EOL
1156          $page = $lessonpages[$pageid];
1157          $answerpage = new stdClass;
1158          // Keep the original page object.
1159          $answerpage->page = $page;
1160          $data ='';
1161  
1162          $answerdata = new stdClass;
1163          // Set some defaults for the answer data.
1164          $answerdata->score = null;
1165          $answerdata->response = null;
1166          $answerdata->responseformat = FORMAT_PLAIN;
1167  
1168          $answerpage->title = format_string($page->title);
1169  
1170          $options = new stdClass;
1171          $options->noclean = true;
1172          $options->overflowdiv = true;
1173          $options->context = $context;
1174          $answerpage->contents = format_text($page->contents, $page->contentsformat, $options);
1175  
1176          $answerpage->qtype = $qtypes[$page->qtype].$page->option_description_string();
1177          $answerpage->grayout = $page->grayout;
1178          $answerpage->context = $context;
1179  
1180          if (empty($userid)) {
1181              // there is no userid, so set these vars and display stats.
1182              $answerpage->grayout = 0;
1183              $useranswer = null;
1184          } elseif ($useranswers = $DB->get_records("lesson_attempts",array("lessonid"=>$lesson->id, "userid"=>$userid, "retry"=>$attempt,"pageid"=>$page->id), "timeseen")) {
1185              // get the user's answer for this page
1186              // need to find the right one
1187              $i = 0;
1188              foreach ($useranswers as $userattempt) {
1189                  $useranswer = $userattempt;
1190                  $i++;
1191                  if ($lesson->maxattempts == $i) {
1192                      break; // reached maxattempts, break out
1193                  }
1194              }
1195          } else {
1196              // user did not answer this page, gray it out and set some nulls
1197              $answerpage->grayout = 1;
1198              $useranswer = null;
1199          }
1200          $i = 0;
1201          $n = 0;
1202          $answerpages[] = $page->report_answers(clone($answerpage), clone($answerdata), $useranswer, $pagestats, $i, $n);
1203          $pageid = $page->nextpageid;
1204      }
1205  
1206      $userstats = new stdClass;
1207      if (!empty($userid)) {
1208          $params = array("lessonid"=>$lesson->id, "userid"=>$userid);
1209  
1210          $alreadycompleted = true;
1211  
1212          if (!$grades = $DB->get_records_select("lesson_grades", "lessonid = :lessonid and userid = :userid", $params, "completed", "*", $attempt, 1)) {
1213              $userstats->grade = -1;
1214              $userstats->completed = -1;
1215              $alreadycompleted = false;
1216          } else {
1217              $userstats->grade = current($grades);
1218              $userstats->completed = $userstats->grade->completed;
1219              $userstats->grade = round($userstats->grade->grade, 2);
1220          }
1221  
1222          if (!$times = $lesson->get_user_timers($userid, 'starttime', '*', $attempt, 1)) {
1223              $userstats->timetotake = -1;
1224              $alreadycompleted = false;
1225          } else {
1226              $userstats->timetotake = current($times);
1227              $userstats->timetotake = $userstats->timetotake->lessontime - $userstats->timetotake->starttime;
1228          }
1229  
1230          if ($alreadycompleted) {
1231              $userstats->gradeinfo = lesson_grade($lesson, $attempt, $userid);
1232          }
1233      }
1234  
1235      return array($answerpages, $userstats);
1236  }
1237  
1238  /**
1239   * Return user's deadline for all lessons in a course, hereby taking into account group and user overrides.
1240   *
1241   * @param int $courseid the course id.
1242   * @return object An object with of all lessonsids and close unixdates in this course,
1243   * taking into account the most lenient overrides, if existing and 0 if no close date is set.
1244   */
1245  function lesson_get_user_deadline($courseid) {
1246      global $DB, $USER;
1247  
1248      // For teacher and manager/admins return lesson's deadline.
1249      if (has_capability('moodle/course:update', context_course::instance($courseid))) {
1250          $sql = "SELECT lesson.id, lesson.deadline AS userdeadline
1251                    FROM {lesson} lesson
1252                   WHERE lesson.course = :courseid";
1253  
1254          $results = $DB->get_records_sql($sql, array('courseid' => $courseid));
1255          return $results;
1256      }
1257  
1258      $sql = "SELECT a.id,
1259                     COALESCE(v.userclose, v.groupclose, a.deadline, 0) AS userdeadline
1260                FROM (
1261                        SELECT lesson.id as lessonid,
1262                               MAX(leo.deadline) AS userclose, MAX(qgo.deadline) AS groupclose
1263                          FROM {lesson} lesson
1264                     LEFT JOIN {lesson_overrides} leo on lesson.id = leo.lessonid AND leo.userid = :userid
1265                     LEFT JOIN {groups_members} gm ON gm.userid = :useringroupid
1266                     LEFT JOIN {lesson_overrides} qgo on lesson.id = qgo.lessonid AND qgo.groupid = gm.groupid
1267                         WHERE lesson.course = :courseid
1268                      GROUP BY lesson.id
1269                     ) v
1270                JOIN {lesson} a ON a.id = v.lessonid";
1271  
1272      $results = $DB->get_records_sql($sql, array('userid' => $USER->id, 'useringroupid' => $USER->id, 'courseid' => $courseid));
1273      return $results;
1274  
1275  }
1276  
1277  /**
1278   * Abstract class that page type's MUST inherit from.
1279   *
1280   * This is the abstract class that ALL add page type forms must extend.
1281   * You will notice that all but two of the methods this class contains are final.
1282   * Essentially the only thing that extending classes can do is extend custom_definition.
1283   * OR if it has a special requirement on creation it can extend construction_override
1284   *
1285   * @abstract
1286   * @copyright  2009 Sam Hemelryk
1287   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1288   */
1289  abstract class lesson_add_page_form_base extends moodleform {
1290  
1291      /**
1292       * This is the classic define that is used to identify this pagetype.
1293       * Will be one of LESSON_*
1294       * @var int
1295       */
1296      public $qtype;
1297  
1298      /**
1299       * The simple string that describes the page type e.g. truefalse, multichoice
1300       * @var string
1301       */
1302      public $qtypestring;
1303  
1304      /**
1305       * An array of options used in the htmleditor
1306       * @var array
1307       */
1308      protected $editoroptions = array();
1309  
1310      /**
1311       * True if this is a standard page of false if it does something special.
1312       * Questions are standard pages, branch tables are not
1313       * @var bool
1314       */
1315      protected $standard = true;
1316  
1317      /**
1318       * Answer format supported by question type.
1319       */
1320      protected $answerformat = '';
1321  
1322      /**
1323       * Response format supported by question type.
1324       */
1325      protected $responseformat = '';
1326  
1327      /**
1328       * Each page type can and should override this to add any custom elements to
1329       * the basic form that they want
1330       */
1331      public function custom_definition() {}
1332  
1333      /**
1334       * Returns answer format used by question type.
1335       */
1336      public function get_answer_format() {
1337          return $this->answerformat;
1338      }
1339  
1340      /**
1341       * Returns response format used by question type.
1342       */
1343      public function get_response_format() {
1344          return $this->responseformat;
1345      }
1346  
1347      /**
1348       * Used to determine if this is a standard page or a special page
1349       * @return bool
1350       */
1351      public final function is_standard() {
1352          return (bool)$this->standard;
1353      }
1354  
1355      /**
1356       * Add the required basic elements to the form.
1357       *
1358       * This method adds the basic elements to the form including title and contents
1359       * and then calls custom_definition();
1360       */
1361      public final function definition() {
1362          global $CFG;
1363          $mform = $this->_form;
1364          $editoroptions = $this->_customdata['editoroptions'];
1365  
1366          if ($this->qtypestring != 'selectaqtype') {
1367              if ($this->_customdata['edit']) {
1368                  $mform->addElement('header', 'qtypeheading', get_string('edit'. $this->qtypestring, 'lesson'));
1369              } else {
1370                  $mform->addElement('header', 'qtypeheading', get_string('add'. $this->qtypestring, 'lesson'));
1371              }
1372          }
1373  
1374          if (!empty($this->_customdata['returnto'])) {
1375              $mform->addElement('hidden', 'returnto', $this->_customdata['returnto']);
1376              $mform->setType('returnto', PARAM_LOCALURL);
1377          }
1378  
1379          $mform->addElement('hidden', 'id');
1380          $mform->setType('id', PARAM_INT);
1381  
1382          $mform->addElement('hidden', 'pageid');
1383          $mform->setType('pageid', PARAM_INT);
1384  
1385          if ($this->standard === true) {
1386              $mform->addElement('hidden', 'qtype');
1387              $mform->setType('qtype', PARAM_INT);
1388  
1389              $mform->addElement('text', 'title', get_string('pagetitle', 'lesson'), array('size'=>70));
1390              $mform->addRule('title', get_string('required'), 'required', null, 'client');
1391              if (!empty($CFG->formatstringstriptags)) {
1392                  $mform->setType('title', PARAM_TEXT);
1393              } else {
1394                  $mform->setType('title', PARAM_CLEANHTML);
1395              }
1396  
1397              $this->editoroptions = array('noclean'=>true, 'maxfiles'=>EDITOR_UNLIMITED_FILES, 'maxbytes'=>$this->_customdata['maxbytes']);
1398              $mform->addElement('editor', 'contents_editor', get_string('pagecontents', 'lesson'), null, $this->editoroptions);
1399              $mform->setType('contents_editor', PARAM_RAW);
1400              $mform->addRule('contents_editor', get_string('required'), 'required', null, 'client');
1401          }
1402  
1403          $this->custom_definition();
1404  
1405          if ($this->_customdata['edit'] === true) {
1406              $mform->addElement('hidden', 'edit', 1);
1407              $mform->setType('edit', PARAM_BOOL);
1408              $this->add_action_buttons(get_string('cancel'), get_string('savepage', 'lesson'));
1409          } else if ($this->qtype === 'questiontype') {
1410              $this->add_action_buttons(get_string('cancel'), get_string('addaquestionpage', 'lesson'));
1411          } else {
1412              $this->add_action_buttons(get_string('cancel'), get_string('savepage', 'lesson'));
1413          }
1414      }
1415  
1416      /**
1417       * Convenience function: Adds a jumpto select element
1418       *
1419       * @param string $name
1420       * @param string|null $label
1421       * @param int $selected The page to select by default
1422       */
1423      protected final function add_jumpto($name, $label=null, $selected=LESSON_NEXTPAGE) {
1424          $title = get_string("jump", "lesson");
1425          if ($label === null) {
1426              $label = $title;
1427          }
1428          if (is_int($name)) {
1429              $name = "jumpto[$name]";
1430          }
1431          $this->_form->addElement('select', $name, $label, $this->_customdata['jumpto']);
1432          $this->_form->setDefault($name, $selected);
1433          $this->_form->addHelpButton($name, 'jumps', 'lesson');
1434      }
1435  
1436      /**
1437       * Convenience function: Adds a score input element
1438       *
1439       * @param string $name
1440       * @param string|null $label
1441       * @param mixed $value The default value
1442       */
1443      protected final function add_score($name, $label=null, $value=null) {
1444          if ($label === null) {
1445              $label = get_string("score", "lesson");
1446          }
1447  
1448          if (is_int($name)) {
1449              $name = "score[$name]";
1450          }
1451          $this->_form->addElement('text', $name, $label, array('size'=>5));
1452          $this->_form->setType($name, PARAM_INT);
1453          if ($value !== null) {
1454              $this->_form->setDefault($name, $value);
1455          }
1456          $this->_form->addHelpButton($name, 'score', 'lesson');
1457  
1458          // Score is only used for custom scoring. Disable the element when not in use to stop some confusion.
1459          if (!$this->_customdata['lesson']->custom) {
1460              $this->_form->freeze($name);
1461          }
1462      }
1463  
1464      /**
1465       * Convenience function: Adds an answer editor
1466       *
1467       * @param int $count The count of the element to add
1468       * @param string $label, null means default
1469       * @param bool $required
1470       * @param string $format
1471       * @param array $help Add help text via the addHelpButton. Must be an array which contains the string identifier and
1472       *                      component as it's elements
1473       * @return void
1474       */
1475      protected final function add_answer($count, $label = null, $required = false, $format= '', array $help = []) {
1476          if ($label === null) {
1477              $label = get_string('answer', 'lesson');
1478          }
1479  
1480          if ($format == LESSON_ANSWER_HTML) {
1481              $this->_form->addElement('editor', 'answer_editor['.$count.']', $label,
1482                      array('rows' => '4', 'columns' => '80'),
1483                      array('noclean' => true, 'maxfiles' => EDITOR_UNLIMITED_FILES, 'maxbytes' => $this->_customdata['maxbytes']));
1484              $this->_form->setType('answer_editor['.$count.']', PARAM_RAW);
1485              $this->_form->setDefault('answer_editor['.$count.']', array('text' => '', 'format' => FORMAT_HTML));
1486          } else {
1487              $this->_form->addElement('text', 'answer_editor['.$count.']', $label,
1488                  array('size' => '50', 'maxlength' => '200'));
1489              $this->_form->setType('answer_editor['.$count.']', PARAM_TEXT);
1490          }
1491  
1492          if ($required) {
1493              $this->_form->addRule('answer_editor['.$count.']', get_string('required'), 'required', null, 'client');
1494          }
1495  
1496          if ($help) {
1497              $this->_form->addHelpButton("answer_editor[$count]", $help['identifier'], $help['component']);
1498          }
1499      }
1500      /**
1501       * Convenience function: Adds an response editor
1502       *
1503       * @param int $count The count of the element to add
1504       * @param string $label, null means default
1505       * @param bool $required
1506       * @return void
1507       */
1508      protected final function add_response($count, $label = null, $required = false) {
1509          if ($label === null) {
1510              $label = get_string('response', 'lesson');
1511          }
1512          $this->_form->addElement('editor', 'response_editor['.$count.']', $label,
1513                   array('rows' => '4', 'columns' => '80'),
1514                   array('noclean' => true, 'maxfiles' => EDITOR_UNLIMITED_FILES, 'maxbytes' => $this->_customdata['maxbytes']));
1515          $this->_form->setType('response_editor['.$count.']', PARAM_RAW);
1516          $this->_form->setDefault('response_editor['.$count.']', array('text' => '', 'format' => FORMAT_HTML));
1517  
1518          if ($required) {
1519              $this->_form->addRule('response_editor['.$count.']', get_string('required'), 'required', null, 'client');
1520          }
1521      }
1522  
1523      /**
1524       * A function that gets called upon init of this object by the calling script.
1525       *
1526       * This can be used to process an immediate action if required. Currently it
1527       * is only used in special cases by non-standard page types.
1528       *
1529       * @return bool
1530       */
1531      public function construction_override($pageid, lesson $lesson) {
1532          return true;
1533      }
1534  }
1535  
1536  
1537  
1538  /**
1539   * Class representation of a lesson
1540   *
1541   * This class is used the interact with, and manage a lesson once instantiated.
1542   * If you need to fetch a lesson object you can do so by calling
1543   *
1544   * <code>
1545   * lesson::load($lessonid);
1546   * // or
1547   * $lessonrecord = $DB->get_record('lesson', $lessonid);
1548   * $lesson = new lesson($lessonrecord);
1549   * </code>
1550   *
1551   * The class itself extends lesson_base as all classes within the lesson module should
1552   *
1553   * These properties are from the database
1554   * @property int $id The id of this lesson
1555   * @property int $course The ID of the course this lesson belongs to
1556   * @property string $name The name of this lesson
1557   * @property int $practice Flag to toggle this as a practice lesson
1558   * @property int $modattempts Toggle to allow the user to go back and review answers
1559   * @property int $usepassword Toggle the use of a password for entry
1560   * @property string $password The password to require users to enter
1561   * @property int $dependency ID of another lesson this lesson is dependent on
1562   * @property string $conditions Conditions of the lesson dependency
1563   * @property int $grade The maximum grade a user can achieve (%)
1564   * @property int $custom Toggle custom scoring on or off
1565   * @property int $ongoing Toggle display of an ongoing score
1566   * @property int $usemaxgrade How retakes are handled (max=1, mean=0)
1567   * @property int $maxanswers The max number of answers or branches
1568   * @property int $maxattempts The maximum number of attempts a user can record
1569   * @property int $review Toggle use or wrong answer review button
1570   * @property int $nextpagedefault Override the default next page
1571   * @property int $feedback Toggles display of default feedback
1572   * @property int $minquestions Sets a minimum value of pages seen when calculating grades
1573   * @property int $maxpages Maximum number of pages this lesson can contain
1574   * @property int $retake Flag to allow users to retake a lesson
1575   * @property int $activitylink Relate this lesson to another lesson
1576   * @property string $mediafile File to pop up to or webpage to display
1577   * @property int $mediaheight Sets the height of the media file popup
1578   * @property int $mediawidth Sets the width of the media file popup
1579   * @property int $mediaclose Toggle display of a media close button
1580   * @property int $slideshow Flag for whether branch pages should be shown as slideshows
1581   * @property int $width Width of slideshow
1582   * @property int $height Height of slideshow
1583   * @property string $bgcolor Background colour of slideshow
1584   * @property int $displayleft Display a left menu
1585   * @property int $displayleftif Sets the condition on which the left menu is displayed
1586   * @property int $progressbar Flag to toggle display of a lesson progress bar
1587   * @property int $available Timestamp of when this lesson becomes available
1588   * @property int $deadline Timestamp of when this lesson is no longer available
1589   * @property int $timemodified Timestamp when lesson was last modified
1590   * @property int $allowofflineattempts Whether to allow the lesson to be attempted offline in the mobile app
1591   *
1592   * These properties are calculated
1593   * @property int $firstpageid Id of the first page of this lesson (prevpageid=0)
1594   * @property int $lastpageid Id of the last page of this lesson (nextpageid=0)
1595   *
1596   * @copyright  2009 Sam Hemelryk
1597   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1598   */
1599  class lesson extends lesson_base {
1600  
1601      /**
1602       * The id of the first page (where prevpageid = 0) gets set and retrieved by
1603       * {@see get_firstpageid()} by directly calling <code>$lesson->firstpageid;</code>
1604       * @var int
1605       */
1606      protected $firstpageid = null;
1607      /**
1608       * The id of the last page (where nextpageid = 0) gets set and retrieved by
1609       * {@see get_lastpageid()} by directly calling <code>$lesson->lastpageid;</code>
1610       * @var int
1611       */
1612      protected $lastpageid = null;
1613      /**
1614       * An array used to cache the pages associated with this lesson after the first
1615       * time they have been loaded.
1616       * A note to developers: If you are going to be working with MORE than one or
1617       * two pages from a lesson you should probably call {@see $lesson->load_all_pages()}
1618       * in order to save excess database queries.
1619       * @var array An array of lesson_page objects
1620       */
1621      protected $pages = array();
1622      /**
1623       * Flag that gets set to true once all of the pages associated with the lesson
1624       * have been loaded.
1625       * @var bool
1626       */
1627      protected $loadedallpages = false;
1628  
1629      /**
1630       * Course module object gets set and retrieved by directly calling <code>$lesson->cm;</code>
1631       * @see get_cm()
1632       * @var stdClass
1633       */
1634      protected $cm = null;
1635  
1636      /**
1637       * Course object gets set and retrieved by directly calling <code>$lesson->courserecord;</code>
1638       * @see get_courserecord()
1639       * @var stdClass
1640       */
1641      protected $courserecord = null;
1642  
1643      /**
1644       * Context object gets set and retrieved by directly calling <code>$lesson->context;</code>
1645       * @see get_context()
1646       * @var stdClass
1647       */
1648      protected $context = null;
1649  
1650      /**
1651       * Constructor method
1652       *
1653       * @param object $properties
1654       * @param stdClass $cm course module object
1655       * @param stdClass $course course object
1656       * @since Moodle 3.3
1657       */
1658      public function __construct($properties, $cm = null, $course = null) {
1659          parent::__construct($properties);
1660          $this->cm = $cm;
1661          $this->courserecord = $course;
1662      }
1663  
1664      /**
1665       * Simply generates a lesson object given an array/object of properties
1666       * Overrides {@see lesson_base->create()}
1667       * @static
1668       * @param object|array $properties
1669       * @return lesson
1670       */
1671      public static function create($properties) {
1672          return new lesson($properties);
1673      }
1674  
1675      /**
1676       * Generates a lesson object from the database given its id
1677       * @static
1678       * @param int $lessonid
1679       * @return lesson
1680       */
1681      public static function load($lessonid) {
1682          global $DB;
1683  
1684          if (!$lesson = $DB->get_record('lesson', array('id' => $lessonid))) {
1685              throw new \moodle_exception('invalidcoursemodule');
1686          }
1687          return new lesson($lesson);
1688      }
1689  
1690      /**
1691       * Deletes this lesson from the database
1692       */
1693      public function delete() {
1694          global $CFG, $DB;
1695          require_once($CFG->libdir.'/gradelib.php');
1696          require_once($CFG->dirroot.'/calendar/lib.php');
1697  
1698          $cm = get_coursemodule_from_instance('lesson', $this->properties->id, $this->properties->course);
1699          $context = context_module::instance($cm->id);
1700  
1701          $this->delete_all_overrides();
1702  
1703          grade_update('mod/lesson', $this->properties->course, 'mod', 'lesson', $this->properties->id, 0, null, array('deleted'=>1));
1704  
1705          // We must delete the module record after we delete the grade item.
1706          $DB->delete_records("lesson", array("id"=>$this->properties->id));
1707          $DB->delete_records("lesson_pages", array("lessonid"=>$this->properties->id));
1708          $DB->delete_records("lesson_answers", array("lessonid"=>$this->properties->id));
1709          $DB->delete_records("lesson_attempts", array("lessonid"=>$this->properties->id));
1710          $DB->delete_records("lesson_grades", array("lessonid"=>$this->properties->id));
1711          $DB->delete_records("lesson_timer", array("lessonid"=>$this->properties->id));
1712          $DB->delete_records("lesson_branch", array("lessonid"=>$this->properties->id));
1713          if ($events = $DB->get_records('event', array("modulename"=>'lesson', "instance"=>$this->properties->id))) {
1714              $coursecontext = context_course::instance($cm->course);
1715              foreach($events as $event) {
1716                  $event->context = $coursecontext;
1717                  $event = calendar_event::load($event);
1718                  $event->delete();
1719              }
1720          }
1721  
1722          // Delete files associated with this module.
1723          $fs = get_file_storage();
1724          $fs->delete_area_files($context->id);
1725  
1726          return true;
1727      }
1728  
1729      /**
1730       * Deletes a lesson override from the database and clears any corresponding calendar events
1731       *
1732       * @param int $overrideid The id of the override being deleted
1733       * @return bool true on success
1734       */
1735      public function delete_override($overrideid) {
1736          global $CFG, $DB;
1737  
1738          require_once($CFG->dirroot . '/calendar/lib.php');
1739  
1740          $cm = get_coursemodule_from_instance('lesson', $this->properties->id, $this->properties->course);
1741  
1742          $override = $DB->get_record('lesson_overrides', array('id' => $overrideid), '*', MUST_EXIST);
1743  
1744          // Delete the events.
1745          $conds = array('modulename' => 'lesson',
1746                  'instance' => $this->properties->id);
1747          if (isset($override->userid)) {
1748              $conds['userid'] = $override->userid;
1749              $cachekey = "{$cm->instance}_u_{$override->userid}";
1750          } else {
1751              $conds['groupid'] = $override->groupid;
1752              $cachekey = "{$cm->instance}_g_{$override->groupid}";
1753          }
1754          $events = $DB->get_records('event', $conds);
1755          foreach ($events as $event) {
1756              $eventold = calendar_event::load($event);
1757              $eventold->delete();
1758          }
1759  
1760          $DB->delete_records('lesson_overrides', array('id' => $overrideid));
1761          cache::make('mod_lesson', 'overrides')->delete($cachekey);
1762  
1763          // Set the common parameters for one of the events we will be triggering.
1764          $params = array(
1765              'objectid' => $override->id,
1766              'context' => context_module::instance($cm->id),
1767              'other' => array(
1768                  'lessonid' => $override->lessonid
1769              )
1770          );
1771          // Determine which override deleted event to fire.
1772          if (!empty($override->userid)) {
1773              $params['relateduserid'] = $override->userid;
1774              $event = \mod_lesson\event\user_override_deleted::create($params);
1775          } else {
1776              $params['other']['groupid'] = $override->groupid;
1777              $event = \mod_lesson\event\group_override_deleted::create($params);
1778          }
1779  
1780          // Trigger the override deleted event.
1781          $event->add_record_snapshot('lesson_overrides', $override);
1782          $event->trigger();
1783  
1784          return true;
1785      }
1786  
1787      /**
1788       * Deletes all lesson overrides from the database and clears any corresponding calendar events
1789       */
1790      public function delete_all_overrides() {
1791          global $DB;
1792  
1793          $overrides = $DB->get_records('lesson_overrides', array('lessonid' => $this->properties->id), 'id');
1794          foreach ($overrides as $override) {
1795              $this->delete_override($override->id);
1796          }
1797      }
1798  
1799      /**
1800       * Checks user enrollment in the current course.
1801       *
1802       * @param int $userid
1803       * @return null|stdClass user record
1804       */
1805      public function is_participant($userid) {
1806          return is_enrolled($this->get_context(), $userid, 'mod/lesson:view', $this->show_only_active_users());
1807      }
1808  
1809      /**
1810       * Check is only active users in course should be shown.
1811       *
1812       * @return bool true if only active users should be shown.
1813       */
1814      public function show_only_active_users() {
1815          return !has_capability('moodle/course:viewsuspendedusers', $this->get_context());
1816      }
1817  
1818      /**
1819       * Updates the lesson properties with override information for a user.
1820       *
1821       * Algorithm:  For each lesson setting, if there is a matching user-specific override,
1822       *   then use that otherwise, if there are group-specific overrides, return the most
1823       *   lenient combination of them.  If neither applies, leave the quiz setting unchanged.
1824       *
1825       *   Special case: if there is more than one password that applies to the user, then
1826       *   lesson->extrapasswords will contain an array of strings giving the remaining
1827       *   passwords.
1828       *
1829       * @param int $userid The userid.
1830       */
1831      public function update_effective_access($userid) {
1832          global $DB;
1833  
1834          // Check for user override.
1835          $override = $DB->get_record('lesson_overrides', array('lessonid' => $this->properties->id, 'userid' => $userid));
1836  
1837          if (!$override) {
1838              $override = new stdClass();
1839              $override->available = null;
1840              $override->deadline = null;
1841              $override->timelimit = null;
1842              $override->review = null;
1843              $override->maxattempts = null;
1844              $override->retake = null;
1845              $override->password = null;
1846          }
1847  
1848          // Check for group overrides.
1849          $groupings = groups_get_user_groups($this->properties->course, $userid);
1850  
1851          if (!empty($groupings[0])) {
1852              // Select all overrides that apply to the User's groups.
1853              list($extra, $params) = $DB->get_in_or_equal(array_values($groupings[0]));
1854              $sql = "SELECT * FROM {lesson_overrides}
1855                      WHERE groupid $extra AND lessonid = ?";
1856              $params[] = $this->properties->id;
1857              $records = $DB->get_records_sql($sql, $params);
1858  
1859              // Combine the overrides.
1860              $availables = array();
1861              $deadlines = array();
1862              $timelimits = array();
1863              $reviews = array();
1864              $attempts = array();
1865              $retakes = array();
1866              $passwords = array();
1867  
1868              foreach ($records as $gpoverride) {
1869                  if (isset($gpoverride->available)) {
1870                      $availables[] = $gpoverride->available;
1871                  }
1872                  if (isset($gpoverride->deadline)) {
1873                      $deadlines[] = $gpoverride->deadline;
1874                  }
1875                  if (isset($gpoverride->timelimit)) {
1876                      $timelimits[] = $gpoverride->timelimit;
1877                  }
1878                  if (isset($gpoverride->review)) {
1879                      $reviews[] = $gpoverride->review;
1880                  }
1881                  if (isset($gpoverride->maxattempts)) {
1882                      $attempts[] = $gpoverride->maxattempts;
1883                  }
1884                  if (isset($gpoverride->retake)) {
1885                      $retakes[] = $gpoverride->retake;
1886                  }
1887                  if (isset($gpoverride->password)) {
1888                      $passwords[] = $gpoverride->password;
1889                  }
1890              }
1891              // If there is a user override for a setting, ignore the group override.
1892              if (is_null($override->available) && count($availables)) {
1893                  $override->available = min($availables);
1894              }
1895              if (is_null($override->deadline) && count($deadlines)) {
1896                  if (in_array(0, $deadlines)) {
1897                      $override->deadline = 0;
1898                  } else {
1899                      $override->deadline = max($deadlines);
1900                  }
1901              }
1902              if (is_null($override->timelimit) && count($timelimits)) {
1903                  if (in_array(0, $timelimits)) {
1904                      $override->timelimit = 0;
1905                  } else {
1906                      $override->timelimit = max($timelimits);
1907                  }
1908              }
1909              if (is_null($override->review) && count($reviews)) {
1910                  $override->review = max($reviews);
1911              }
1912              if (is_null($override->maxattempts) && count($attempts)) {
1913                  $override->maxattempts = max($attempts);
1914              }
1915              if (is_null($override->retake) && count($retakes)) {
1916                  $override->retake = max($retakes);
1917              }
1918              if (is_null($override->password) && count($passwords)) {
1919                  $override->password = array_shift($passwords);
1920                  if (count($passwords)) {
1921                      $override->extrapasswords = $passwords;
1922                  }
1923              }
1924  
1925          }
1926  
1927          // Merge with lesson defaults.
1928          $keys = array('available', 'deadline', 'timelimit', 'maxattempts', 'review', 'retake');
1929          foreach ($keys as $key) {
1930              if (isset($override->{$key})) {
1931                  $this->properties->{$key} = $override->{$key};
1932              }
1933          }
1934  
1935          // Special handling of lesson usepassword and password.
1936          if (isset($override->password)) {
1937              if ($override->password == '') {
1938                  $this->properties->usepassword = 0;
1939              } else {
1940                  $this->properties->usepassword = 1;
1941                  $this->properties->password = $override->password;
1942                  if (isset($override->extrapasswords)) {
1943                      $this->properties->extrapasswords = $override->extrapasswords;
1944                  }
1945              }
1946          }
1947      }
1948  
1949      /**
1950       * Fetches messages from the session that may have been set in previous page
1951       * actions.
1952       *
1953       * <code>
1954       * // Do not call this method directly instead use
1955       * $lesson->messages;
1956       * </code>
1957       *
1958       * @return array
1959       */
1960      protected function get_messages() {
1961          global $SESSION;
1962  
1963          $messages = array();
1964          if (!empty($SESSION->lesson_messages) && is_array($SESSION->lesson_messages) && array_key_exists($this->properties->id, $SESSION->lesson_messages)) {
1965              $messages = $SESSION->lesson_messages[$this->properties->id];
1966              unset($SESSION->lesson_messages[$this->properties->id]);
1967          }
1968  
1969          return $messages;
1970      }
1971  
1972      /**
1973       * Get all of the attempts for the current user.
1974       *
1975       * @param int $retries
1976       * @param bool $correct Optional: only fetch correct attempts
1977       * @param int $pageid Optional: only fetch attempts at the given page
1978       * @param int $userid Optional: defaults to the current user if not set
1979       * @return array|false
1980       */
1981      public function get_attempts($retries, $correct=false, $pageid=null, $userid=null) {
1982          global $USER, $DB;
1983          $params = array("lessonid"=>$this->properties->id, "userid"=>$userid, "retry"=>$retries);
1984          if ($correct) {
1985              $params['correct'] = 1;
1986          }
1987          if ($pageid !== null) {
1988              $params['pageid'] = $pageid;
1989          }
1990          if ($userid === null) {
1991              $params['userid'] = $USER->id;
1992          }
1993          return $DB->get_records('lesson_attempts', $params, 'timeseen ASC');
1994      }
1995  
1996  
1997      /**
1998       * Get a list of content pages (formerly known as branch tables) viewed in the lesson for the given user during an attempt.
1999       *
2000       * @param  int $lessonattempt the lesson attempt number (also known as retries)
2001       * @param  int $userid        the user id to retrieve the data from
2002       * @param  string $sort          an order to sort the results in (a valid SQL ORDER BY parameter)
2003       * @param  string $fields        a comma separated list of fields to return
2004       * @return array of pages
2005       * @since  Moodle 3.3
2006       */
2007      public function get_content_pages_viewed($lessonattempt, $userid = null, $sort = '', $fields = '*') {
2008          global $USER, $DB;
2009  
2010          if ($userid === null) {
2011              $userid = $USER->id;
2012          }
2013          $conditions = array("lessonid" => $this->properties->id, "userid" => $userid, "retry" => $lessonattempt);
2014          return $DB->get_records('lesson_branch', $conditions, $sort, $fields);
2015      }
2016  
2017      /**
2018       * Returns the first page for the lesson or false if there isn't one.
2019       *
2020       * This method should be called via the magic method __get();
2021       * <code>
2022       * $firstpage = $lesson->firstpage;
2023       * </code>
2024       *
2025       * @return lesson_page|bool Returns the lesson_page specialised object or false
2026       */
2027      protected function get_firstpage() {
2028          $pages = $this->load_all_pages();
2029          if (count($pages) > 0) {
2030              foreach ($pages as $page) {
2031                  if ((int)$page->prevpageid === 0) {
2032                      return $page;
2033                  }
2034              }
2035          }
2036          return false;
2037      }
2038  
2039      /**
2040       * Returns the last page for the lesson or false if there isn't one.
2041       *
2042       * This method should be called via the magic method __get();
2043       * <code>
2044       * $lastpage = $lesson->lastpage;
2045       * </code>
2046       *
2047       * @return lesson_page|bool Returns the lesson_page specialised object or false
2048       */
2049      protected function get_lastpage() {
2050          $pages = $this->load_all_pages();
2051          if (count($pages) > 0) {
2052              foreach ($pages as $page) {
2053                  if ((int)$page->nextpageid === 0) {
2054                      return $page;
2055                  }
2056              }
2057          }
2058          return false;
2059      }
2060  
2061      /**
2062       * Returns the id of the first page of this lesson. (prevpageid = 0)
2063       * @return int
2064       */
2065      protected function get_firstpageid() {
2066          global $DB;
2067          if ($this->firstpageid == null) {
2068              if (!$this->loadedallpages) {
2069                  $firstpageid = $DB->get_field('lesson_pages', 'id', array('lessonid'=>$this->properties->id, 'prevpageid'=>0));
2070                  if (!$firstpageid) {
2071                      throw new \moodle_exception('cannotfindfirstpage', 'lesson');
2072                  }
2073                  $this->firstpageid = $firstpageid;
2074              } else {
2075                  $firstpage = $this->get_firstpage();
2076                  $this->firstpageid = $firstpage->id;
2077              }
2078          }
2079          return $this->firstpageid;
2080      }
2081  
2082      /**
2083       * Returns the id of the last page of this lesson. (nextpageid = 0)
2084       * @return int
2085       */
2086      public function get_lastpageid() {
2087          global $DB;
2088          if ($this->lastpageid == null) {
2089              if (!$this->loadedallpages) {
2090                  $lastpageid = $DB->get_field('lesson_pages', 'id', array('lessonid'=>$this->properties->id, 'nextpageid'=>0));
2091                  if (!$lastpageid) {
2092                      throw new \moodle_exception('cannotfindlastpage', 'lesson');
2093                  }
2094                  $this->lastpageid = $lastpageid;
2095              } else {
2096                  $lastpageid = $this->get_lastpage();
2097                  $this->lastpageid = $lastpageid->id;
2098              }
2099          }
2100  
2101          return $this->lastpageid;
2102      }
2103  
2104       /**
2105       * Gets the next page id to display after the one that is provided.
2106       * @param int $nextpageid
2107       * @return bool
2108       */
2109      public function get_next_page($nextpageid) {
2110          global $USER, $DB;
2111          $allpages = $this->load_all_pages();
2112          if ($this->properties->nextpagedefault) {
2113              // in Flash Card mode...first get number of retakes
2114              $nretakes = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id));
2115              shuffle($allpages);
2116              $found = false;
2117              if ($this->properties->nextpagedefault == LESSON_UNSEENPAGE) {
2118                  foreach ($allpages as $nextpage) {
2119                      if (!$DB->count_records("lesson_attempts", array("pageid" => $nextpage->id, "userid" => $USER->id, "retry" => $nretakes))) {
2120                          $found = true;
2121                          break;
2122                      }
2123                  }
2124              } elseif ($this->properties->nextpagedefault == LESSON_UNANSWEREDPAGE) {
2125                  foreach ($allpages as $nextpage) {
2126                      if (!$DB->count_records("lesson_attempts", array('pageid' => $nextpage->id, 'userid' => $USER->id, 'correct' => 1, 'retry' => $nretakes))) {
2127                          $found = true;
2128                          break;
2129                      }
2130                  }
2131              }
2132              if ($found) {
2133                  if ($this->properties->maxpages) {
2134                      // check number of pages viewed (in the lesson)
2135                      if ($DB->count_records("lesson_attempts", array("lessonid" => $this->properties->id, "userid" => $USER->id, "retry" => $nretakes)) >= $this->properties->maxpages) {
2136                          return LESSON_EOL;
2137                      }
2138                  }
2139                  return $nextpage->id;
2140              }
2141          }
2142          // In a normal lesson mode
2143          foreach ($allpages as $nextpage) {
2144              if ((int)$nextpage->id === (int)$nextpageid) {
2145                  return $nextpage->id;
2146              }
2147          }
2148          return LESSON_EOL;
2149      }
2150  
2151      /**
2152       * Sets a message against the session for this lesson that will displayed next
2153       * time the lesson processes messages
2154       *
2155       * @param string $message
2156       * @param string $class
2157       * @param string $align
2158       * @return bool
2159       */
2160      public function add_message($message, $class="notifyproblem", $align='center') {
2161          global $SESSION;
2162  
2163          if (empty($SESSION->lesson_messages) || !is_array($SESSION->lesson_messages)) {
2164              $SESSION->lesson_messages = array();
2165              $SESSION->lesson_messages[$this->properties->id] = array();
2166          } else if (!array_key_exists($this->properties->id, $SESSION->lesson_messages)) {
2167              $SESSION->lesson_messages[$this->properties->id] = array();
2168          }
2169  
2170          $SESSION->lesson_messages[$this->properties->id][] = array($message, $class, $align);
2171  
2172          return true;
2173      }
2174  
2175      /**
2176       * Check if the lesson is accessible at the present time
2177       * @return bool True if the lesson is accessible, false otherwise
2178       */
2179      public function is_accessible() {
2180          $available = $this->properties->available;
2181          $deadline = $this->properties->deadline;
2182          return (($available == 0 || time() >= $available) && ($deadline == 0 || time() < $deadline));
2183      }
2184  
2185      /**
2186       * Starts the lesson time for the current user
2187       * @return bool Returns true
2188       */
2189      public function start_timer() {
2190          global $USER, $DB;
2191  
2192          $cm = get_coursemodule_from_instance('lesson', $this->properties()->id, $this->properties()->course,
2193              false, MUST_EXIST);
2194  
2195          // Trigger lesson started event.
2196          $event = \mod_lesson\event\lesson_started::create(array(
2197              'objectid' => $this->properties()->id,
2198              'context' => context_module::instance($cm->id),
2199              'courseid' => $this->properties()->course
2200          ));
2201          $event->trigger();
2202  
2203          $USER->startlesson[$this->properties->id] = true;
2204  
2205          $timenow = time();
2206          $startlesson = new stdClass;
2207          $startlesson->lessonid = $this->properties->id;
2208          $startlesson->userid = $USER->id;
2209          $startlesson->starttime = $timenow;
2210          $startlesson->lessontime = $timenow;
2211          if (WS_SERVER) {
2212              $startlesson->timemodifiedoffline = $timenow;
2213          }
2214          $DB->insert_record('lesson_timer', $startlesson);
2215          if ($this->properties->timelimit) {
2216              $this->add_message(get_string('timelimitwarning', 'lesson', format_time($this->properties->timelimit)), 'center');
2217          }
2218          return true;
2219      }
2220  
2221      /**
2222       * Updates the timer to the current time and returns the new timer object
2223       * @param bool $restart If set to true the timer is restarted
2224       * @param bool $continue If set to true AND $restart=true then the timer
2225       *                        will continue from a previous attempt
2226       * @return stdClass The new timer
2227       */
2228      public function update_timer($restart=false, $continue=false, $endreached =false) {
2229          global $USER, $DB;
2230  
2231          $cm = get_coursemodule_from_instance('lesson', $this->properties->id, $this->properties->course);
2232  
2233          // clock code
2234          // get time information for this user
2235          if (!$timer = $this->get_user_timers($USER->id, 'starttime DESC', '*', 0, 1)) {
2236              $this->start_timer();
2237              $timer = $this->get_user_timers($USER->id, 'starttime DESC', '*', 0, 1);
2238          }
2239          $timer = current($timer); // This will get the latest start time record.
2240  
2241          if ($restart) {
2242              if ($continue) {
2243                  // continue a previous test, need to update the clock  (think this option is disabled atm)
2244                  $timer->starttime = time() - ($timer->lessontime - $timer->starttime);
2245  
2246                  // Trigger lesson resumed event.
2247                  $event = \mod_lesson\event\lesson_resumed::create(array(
2248                      'objectid' => $this->properties->id,
2249                      'context' => context_module::instance($cm->id),
2250                      'courseid' => $this->properties->course
2251                  ));
2252                  $event->trigger();
2253  
2254              } else {
2255                  // starting over, so reset the clock
2256                  $timer->starttime = time();
2257  
2258                  // Trigger lesson restarted event.
2259                  $event = \mod_lesson\event\lesson_restarted::create(array(
2260                      'objectid' => $this->properties->id,
2261                      'context' => context_module::instance($cm->id),
2262                      'courseid' => $this->properties->course
2263                  ));
2264                  $event->trigger();
2265  
2266              }
2267          }
2268  
2269          $timenow = time();
2270          $timer->lessontime = $timenow;
2271          if (WS_SERVER) {
2272              $timer->timemodifiedoffline = $timenow;
2273          }
2274          $timer->completed = $endreached;
2275          $DB->update_record('lesson_timer', $timer);
2276  
2277          // Update completion state.
2278          $cm = get_coursemodule_from_instance('lesson', $this->properties()->id, $this->properties()->course,
2279              false, MUST_EXIST);
2280          $course = get_course($cm->course);
2281          $completion = new completion_info($course);
2282          if ($completion->is_enabled($cm) && $this->properties()->completiontimespent > 0) {
2283              $completion->update_state($cm, COMPLETION_COMPLETE);
2284          }
2285          return $timer;
2286      }
2287  
2288      /**
2289       * Updates the timer to the current time then stops it by unsetting the user var
2290       * @return bool Returns true
2291       */
2292      public function stop_timer() {
2293          global $USER, $DB;
2294          unset($USER->startlesson[$this->properties->id]);
2295  
2296          $cm = get_coursemodule_from_instance('lesson', $this->properties()->id, $this->properties()->course,
2297              false, MUST_EXIST);
2298  
2299          // Trigger lesson ended event.
2300          $event = \mod_lesson\event\lesson_ended::create(array(
2301              'objectid' => $this->properties()->id,
2302              'context' => context_module::instance($cm->id),
2303              'courseid' => $this->properties()->course
2304          ));
2305          $event->trigger();
2306  
2307          return $this->update_timer(false, false, true);
2308      }
2309  
2310      /**
2311       * Checks to see if the lesson has pages
2312       */
2313      public function has_pages() {
2314          global $DB;
2315          $pagecount = $DB->count_records('lesson_pages', array('lessonid'=>$this->properties->id));
2316          return ($pagecount>0);
2317      }
2318  
2319      /**
2320       * Returns the link for the related activity
2321       * @return string
2322       */
2323      public function link_for_activitylink() {
2324          global $DB;
2325          $module = $DB->get_record('course_modules', array('id' => $this->properties->activitylink));
2326          if ($module) {
2327              $modname = $DB->get_field('modules', 'name', array('id' => $module->module));
2328              if ($modname) {
2329                  $instancename = $DB->get_field($modname, 'name', array('id' => $module->instance));
2330                  if ($instancename) {
2331                      return html_writer::link(new moodle_url('/mod/'.$modname.'/view.php',
2332                          array('id' => $this->properties->activitylink)), get_string('activitylinkname',
2333                          'lesson', $instancename), array('class' => 'centerpadded lessonbutton standardbutton pr-3'));
2334                  }
2335              }
2336          }
2337          return '';
2338      }
2339  
2340      /**
2341       * Loads the requested page.
2342       *
2343       * This function will return the requested page id as either a specialised
2344       * lesson_page object OR as a generic lesson_page.
2345       * If the page has been loaded previously it will be returned from the pages
2346       * array, otherwise it will be loaded from the database first
2347       *
2348       * @param int $pageid
2349       * @return lesson_page A lesson_page object or an object that extends it
2350       */
2351      public function load_page($pageid) {
2352          if (!array_key_exists($pageid, $this->pages)) {
2353              $manager = lesson_page_type_manager::get($this);
2354              $this->pages[$pageid] = $manager->load_page($pageid, $this);
2355          }
2356          return $this->pages[$pageid];
2357      }
2358  
2359      /**
2360       * Loads ALL of the pages for this lesson
2361       *
2362       * @return array An array containing all pages from this lesson
2363       */
2364      public function load_all_pages() {
2365          if (!$this->loadedallpages) {
2366              $manager = lesson_page_type_manager::get($this);
2367              $this->pages = $manager->load_all_pages($this);
2368              $this->loadedallpages = true;
2369          }
2370          return $this->pages;
2371      }
2372  
2373      /**
2374       * Duplicate the lesson page.
2375       *
2376       * @param  int $pageid Page ID of the page to duplicate.
2377       * @return void.
2378       */
2379      public function duplicate_page($pageid) {
2380          global $PAGE;
2381          $cm = get_coursemodule_from_instance('lesson', $this->properties->id, $this->properties->course);
2382          $context = context_module::instance($cm->id);
2383          // Load the page.
2384          $page = $this->load_page($pageid);
2385          $properties = $page->properties();
2386          // The create method checks to see if these properties are set and if not sets them to zero, hence the unsetting here.
2387          if (!$properties->qoption) {
2388              unset($properties->qoption);
2389          }
2390          if (!$properties->layout) {
2391              unset($properties->layout);
2392          }
2393          if (!$properties->display) {
2394              unset($properties->display);
2395          }
2396  
2397          $properties->pageid = $pageid;
2398          // Add text and format into the format required to create a new page.
2399          $properties->contents_editor = array(
2400              'text' => $properties->contents,
2401              'format' => $properties->contentsformat
2402          );
2403          $answers = $page->get_answers();
2404          // Answers need to be added to $properties.
2405          $i = 0;
2406          $answerids = array();
2407          foreach ($answers as $answer) {
2408              // Needs to be rearranged to work with the create function.
2409              $properties->answer_editor[$i] = array(
2410                  'text' => $answer->answer,
2411                  'format' => $answer->answerformat
2412              );
2413  
2414              $properties->response_editor[$i] = array(
2415                'text' => $answer->response,
2416                'format' => $answer->responseformat
2417              );
2418              $answerids[] = $answer->id;
2419  
2420              $properties->jumpto[$i] = $answer->jumpto;
2421              $properties->score[$i] = $answer->score;
2422  
2423              $i++;
2424          }
2425          // Create the duplicate page.
2426          $newlessonpage = lesson_page::create($properties, $this, $context, $PAGE->course->maxbytes);
2427          $newanswers = $newlessonpage->get_answers();
2428          // Copy over the file areas as well.
2429          $this->copy_page_files('page_contents', $pageid, $newlessonpage->id, $context->id);
2430          $j = 0;
2431          foreach ($newanswers as $answer) {
2432              if (isset($answer->answer) && strpos($answer->answer, '@@PLUGINFILE@@') !== false) {
2433                  $this->copy_page_files('page_answers', $answerids[$j], $answer->id, $context->id);
2434              }
2435              if (isset($answer->response) && !is_array($answer->response) && strpos($answer->response, '@@PLUGINFILE@@') !== false) {
2436                  $this->copy_page_files('page_responses', $answerids[$j], $answer->id, $context->id);
2437              }
2438              $j++;
2439          }
2440      }
2441  
2442      /**
2443       * Copy the files from one page to another.
2444       *
2445       * @param  string $filearea Area that the files are stored.
2446       * @param  int $itemid Item ID.
2447       * @param  int $newitemid The item ID for the new page.
2448       * @param  int $contextid Context ID for this page.
2449       * @return void.
2450       */
2451      protected function copy_page_files($filearea, $itemid, $newitemid, $contextid) {
2452          $fs = get_file_storage();
2453          $files = $fs->get_area_files($contextid, 'mod_lesson', $filearea, $itemid);
2454          foreach ($files as $file) {
2455              $fieldupdates = array('itemid' => $newitemid);
2456              $fs->create_file_from_storedfile($fieldupdates, $file);
2457          }
2458      }
2459  
2460      /**
2461       * Determines if a jumpto value is correct or not.
2462       *
2463       * returns true if jumpto page is (logically) after the pageid page or
2464       * if the jumpto value is a special value.  Returns false in all other cases.
2465       *
2466       * @param int $pageid Id of the page from which you are jumping from.
2467       * @param int $jumpto The jumpto number.
2468       * @return boolean True or false after a series of tests.
2469       **/
2470      public function jumpto_is_correct($pageid, $jumpto) {
2471          global $DB;
2472  
2473          // first test the special values
2474          if (!$jumpto) {
2475              // same page
2476              return false;
2477          } elseif ($jumpto == LESSON_NEXTPAGE) {
2478              return true;
2479          } elseif ($jumpto == LESSON_UNSEENBRANCHPAGE) {
2480              return true;
2481          } elseif ($jumpto == LESSON_RANDOMPAGE) {
2482              return true;
2483          } elseif ($jumpto == LESSON_CLUSTERJUMP) {
2484              return true;
2485          } elseif ($jumpto == LESSON_EOL) {
2486              return true;
2487          }
2488  
2489          $pages = $this->load_all_pages();
2490          $apageid = $pages[$pageid]->nextpageid;
2491          while ($apageid != 0) {
2492              if ($jumpto == $apageid) {
2493                  return true;
2494              }
2495              $apageid = $pages[$apageid]->nextpageid;
2496          }
2497          return false;
2498      }
2499  
2500      /**
2501       * Returns the time a user has remaining on this lesson
2502       * @param int $starttime Starttime timestamp
2503       * @return string
2504       */
2505      public function time_remaining($starttime) {
2506          $timeleft = $starttime + $this->properties->timelimit - time();
2507          $hours = floor($timeleft/3600);
2508          $timeleft = $timeleft - ($hours * 3600);
2509          $minutes = floor($timeleft/60);
2510          $secs = $timeleft - ($minutes * 60);
2511  
2512          if ($minutes < 10) {
2513              $minutes = "0$minutes";
2514          }
2515          if ($secs < 10) {
2516              $secs = "0$secs";
2517          }
2518          $output   = array();
2519          $output[] = $hours;
2520          $output[] = $minutes;
2521          $output[] = $secs;
2522          $output = implode(':', $output);
2523          return $output;
2524      }
2525  
2526      /**
2527       * Interprets LESSON_CLUSTERJUMP jumpto value.
2528       *
2529       * This will select a page randomly
2530       * and the page selected will be inbetween a cluster page and end of clutter or end of lesson
2531       * and the page selected will be a page that has not been viewed already
2532       * and if any pages are within a branch table or end of branch then only 1 page within
2533       * the branch table or end of branch will be randomly selected (sub clustering).
2534       *
2535       * @param int $pageid Id of the current page from which we are jumping from.
2536       * @param int $userid Id of the user.
2537       * @return int The id of the next page.
2538       **/
2539      public function cluster_jump($pageid, $userid=null) {
2540          global $DB, $USER;
2541  
2542          if ($userid===null) {
2543              $userid = $USER->id;
2544          }
2545          // get the number of retakes
2546          if (!$retakes = $DB->count_records("lesson_grades", array("lessonid"=>$this->properties->id, "userid"=>$userid))) {
2547              $retakes = 0;
2548          }
2549          // get all the lesson_attempts aka what the user has seen
2550          $seenpages = array();
2551          if ($attempts = $this->get_attempts($retakes)) {
2552              foreach ($attempts as $attempt) {
2553                  $seenpages[$attempt->pageid] = $attempt->pageid;
2554              }
2555  
2556          }
2557  
2558          // get the lesson pages
2559          $lessonpages = $this->load_all_pages();
2560          // find the start of the cluster
2561          while ($pageid != 0) { // this condition should not be satisfied... should be a cluster page
2562              if ($lessonpages[$pageid]->qtype == LESSON_PAGE_CLUSTER) {
2563                  break;
2564              }
2565              $pageid = $lessonpages[$pageid]->prevpageid;
2566          }
2567  
2568          $clusterpages = array();
2569          $clusterpages = $this->get_sub_pages_of($pageid, array(LESSON_PAGE_ENDOFCLUSTER));
2570          $unseen = array();
2571          foreach ($clusterpages as $key=>$cluster) {
2572              // Remove the page if  it is in a branch table or is an endofbranch.
2573              if ($this->is_sub_page_of_type($cluster->id,
2574                      array(LESSON_PAGE_BRANCHTABLE), array(LESSON_PAGE_ENDOFBRANCH, LESSON_PAGE_CLUSTER))
2575                      || $cluster->qtype == LESSON_PAGE_ENDOFBRANCH) {
2576                  unset($clusterpages[$key]);
2577              } else if ($cluster->qtype == LESSON_PAGE_BRANCHTABLE) {
2578                  // If branchtable, check to see if any pages inside have been viewed.
2579                  $branchpages = $this->get_sub_pages_of($cluster->id, array(LESSON_PAGE_BRANCHTABLE, LESSON_PAGE_ENDOFBRANCH));
2580                  $flag = true;
2581                  foreach ($branchpages as $branchpage) {
2582                      if (array_key_exists($branchpage->id, $seenpages)) {  // Check if any of the pages have been viewed.
2583                          $flag = false;
2584                      }
2585                  }
2586                  if ($flag && count($branchpages) > 0) {
2587                      // Add branch table.
2588                      $unseen[] = $cluster;
2589                  }
2590              } elseif ($cluster->is_unseen($seenpages)) {
2591                  $unseen[] = $cluster;
2592              }
2593          }
2594  
2595          if (count($unseen) > 0) {
2596              // it does not contain elements, then use exitjump, otherwise find out next page/branch
2597              $nextpage = $unseen[rand(0, count($unseen)-1)];
2598              if ($nextpage->qtype == LESSON_PAGE_BRANCHTABLE) {
2599                  // if branch table, then pick a random page inside of it
2600                  $branchpages = $this->get_sub_pages_of($nextpage->id, array(LESSON_PAGE_BRANCHTABLE, LESSON_PAGE_ENDOFBRANCH));
2601                  return $branchpages[rand(0, count($branchpages)-1)]->id;
2602              } else { // otherwise, return the page's id
2603                  return $nextpage->id;
2604              }
2605          } else {
2606              // seen all there is to see, leave the cluster
2607              if (end($clusterpages)->nextpageid == 0) {
2608                  return LESSON_EOL;
2609              } else {
2610                  $clusterendid = $pageid;
2611                  while ($clusterendid != 0) { // This condition should not be satisfied... should be an end of cluster page.
2612                      if ($lessonpages[$clusterendid]->qtype == LESSON_PAGE_ENDOFCLUSTER) {
2613                          break;
2614                      }
2615                      $clusterendid = $lessonpages[$clusterendid]->nextpageid;
2616                  }
2617                  $exitjump = $DB->get_field("lesson_answers", "jumpto", array("pageid" => $clusterendid, "lessonid" => $this->properties->id));
2618                  if ($exitjump == LESSON_NEXTPAGE) {
2619                      $exitjump = $lessonpages[$clusterendid]->nextpageid;
2620                  }
2621                  if ($exitjump == 0) {
2622                      return LESSON_EOL;
2623                  } else if (in_array($exitjump, array(LESSON_EOL, LESSON_PREVIOUSPAGE))) {
2624                      return $exitjump;
2625                  } else {
2626                      if (!array_key_exists($exitjump, $lessonpages)) {
2627                          $found = false;
2628                          foreach ($lessonpages as $page) {
2629                              if ($page->id === $clusterendid) {
2630                                  $found = true;
2631                              } else if ($page->qtype == LESSON_PAGE_ENDOFCLUSTER) {
2632                                  $exitjump = $DB->get_field("lesson_answers", "jumpto", array("pageid" => $page->id, "lessonid" => $this->properties->id));
2633                                  if ($exitjump == LESSON_NEXTPAGE) {
2634                                      $exitjump = $lessonpages[$page->id]->nextpageid;
2635                                  }
2636                                  break;
2637                              }
2638                          }
2639                      }
2640                      if (!array_key_exists($exitjump, $lessonpages)) {
2641                          return LESSON_EOL;
2642                      }
2643                      // Check to see that the return type is not a cluster.
2644                      if ($lessonpages[$exitjump]->qtype == LESSON_PAGE_CLUSTER) {
2645                          // If the exitjump is a cluster then go through this function again and try to find an unseen question.
2646                          $exitjump = $this->cluster_jump($exitjump, $userid);
2647                      }
2648                      return $exitjump;
2649                  }
2650              }
2651          }
2652      }
2653  
2654      /**
2655       * Finds all pages that appear to be a subtype of the provided pageid until
2656       * an end point specified within $ends is encountered or no more pages exist
2657       *
2658       * @param int $pageid
2659       * @param array $ends An array of LESSON_PAGE_* types that signify an end of
2660       *               the subtype
2661       * @return array An array of specialised lesson_page objects
2662       */
2663      public function get_sub_pages_of($pageid, array $ends) {
2664          $lessonpages = $this->load_all_pages();
2665          $pageid = $lessonpages[$pageid]->nextpageid;  // move to the first page after the branch table
2666          $pages = array();
2667  
2668          while (true) {
2669              if ($pageid == 0 || in_array($lessonpages[$pageid]->qtype, $ends)) {
2670                  break;
2671              }
2672              $pages[] = $lessonpages[$pageid];
2673              $pageid = $lessonpages[$pageid]->nextpageid;
2674          }
2675  
2676          return $pages;
2677      }
2678  
2679      /**
2680       * Checks to see if the specified page[id] is a subpage of a type specified in
2681       * the $types array, until either there are no more pages of we find a type
2682       * corresponding to that of a type specified in $ends
2683       *
2684       * @param int $pageid The id of the page to check
2685       * @param array $types An array of types that would signify this page was a subpage
2686       * @param array $ends An array of types that mean this is not a subpage
2687       * @return bool
2688       */
2689      public function is_sub_page_of_type($pageid, array $types, array $ends) {
2690          $pages = $this->load_all_pages();
2691          $pageid = $pages[$pageid]->prevpageid; // move up one
2692  
2693          array_unshift($ends, 0);
2694          // go up the pages till branch table
2695          while (true) {
2696              if ($pageid==0 || in_array($pages[$pageid]->qtype, $ends)) {
2697                  return false;
2698              } else if (in_array($pages[$pageid]->qtype, $types)) {
2699                  return true;
2700              }
2701              $pageid = $pages[$pageid]->prevpageid;
2702          }
2703      }
2704  
2705      /**
2706       * Move a page resorting all other pages.
2707       *
2708       * @param int $pageid
2709       * @param int $after
2710       * @return void
2711       */
2712      public function resort_pages($pageid, $after) {
2713          global $CFG;
2714  
2715          $cm = get_coursemodule_from_instance('lesson', $this->properties->id, $this->properties->course);
2716          $context = context_module::instance($cm->id);
2717  
2718          $pages = $this->load_all_pages();
2719  
2720          if (!array_key_exists($pageid, $pages) || ($after!=0 && !array_key_exists($after, $pages))) {
2721              throw new \moodle_exception('cannotfindpages', 'lesson', "$CFG->wwwroot/mod/lesson/edit.php?id=$cm->id");
2722          }
2723  
2724          $pagetomove = clone($pages[$pageid]);
2725          unset($pages[$pageid]);
2726  
2727          $pageids = array();
2728          if ($after === 0) {
2729              $pageids['p0'] = $pageid;
2730          }
2731          foreach ($pages as $page) {
2732              $pageids[] = $page->id;
2733              if ($page->id == $after) {
2734                  $pageids[] = $pageid;
2735              }
2736          }
2737  
2738          $pageidsref = $pageids;
2739          reset($pageidsref);
2740          $prev = 0;
2741          $next = next($pageidsref);
2742          foreach ($pageids as $pid) {
2743              if ($pid === $pageid) {
2744                  $page = $pagetomove;
2745              } else {
2746                  $page = $pages[$pid];
2747              }
2748              if ($page->prevpageid != $prev || $page->nextpageid != $next) {
2749                  $page->move($next, $prev);
2750  
2751                  if ($pid === $pageid) {
2752                      // We will trigger an event.
2753                      $pageupdated = array('next' => $next, 'prev' => $prev);
2754                  }
2755              }
2756  
2757              $prev = $page->id;
2758              $next = next($pageidsref);
2759              if (!$next) {
2760                  $next = 0;
2761              }
2762          }
2763  
2764          // Trigger an event: page moved.
2765          if (!empty($pageupdated)) {
2766              $eventparams = array(
2767                  'context' => $context,
2768                  'objectid' => $pageid,
2769                  'other' => array(
2770                      'pagetype' => $page->get_typestring(),
2771                      'prevpageid' => $pageupdated['prev'],
2772                      'nextpageid' => $pageupdated['next']
2773                  )
2774              );
2775              $event = \mod_lesson\event\page_moved::create($eventparams);
2776              $event->trigger();
2777          }
2778  
2779      }
2780  
2781      /**
2782       * Return the lesson context object.
2783       *
2784       * @return stdClass context
2785       * @since  Moodle 3.3
2786       */
2787      public function get_context() {
2788          if ($this->context == null) {
2789              $this->context = context_module::instance($this->get_cm()->id);
2790          }
2791          return $this->context;
2792      }
2793  
2794      /**
2795       * Set the lesson course module object.
2796       *
2797       * @param stdClass $cm course module objct
2798       * @since  Moodle 3.3
2799       */
2800      private function set_cm($cm) {
2801          $this->cm = $cm;
2802      }
2803  
2804      /**
2805       * Return the lesson course module object.
2806       *
2807       * @return stdClass course module
2808       * @since  Moodle 3.3
2809       */
2810      public function get_cm() {
2811          if ($this->cm == null) {
2812              $this->cm = get_coursemodule_from_instance('lesson', $this->properties->id);
2813          }
2814          return $this->cm;
2815      }
2816  
2817      /**
2818       * Set the lesson course object.
2819       *
2820       * @param stdClass $course course objct
2821       * @since  Moodle 3.3
2822       */
2823      private function set_courserecord($course) {
2824          $this->courserecord = $course;
2825      }
2826  
2827      /**
2828       * Return the lesson course object.
2829       *
2830       * @return stdClass course
2831       * @since  Moodle 3.3
2832       */
2833      public function get_courserecord() {
2834          global $DB;
2835  
2836          if ($this->courserecord == null) {
2837              $this->courserecord = $DB->get_record('course', array('id' => $this->properties->course));
2838          }
2839          return $this->courserecord;
2840      }
2841  
2842      /**
2843       * Check if the user can manage the lesson activity.
2844       *
2845       * @return bool true if the user can manage the lesson
2846       * @since  Moodle 3.3
2847       */
2848      public function can_manage() {
2849          return has_capability('mod/lesson:manage', $this->get_context());
2850      }
2851  
2852      /**
2853       * Check if time restriction is applied.
2854       *
2855       * @return mixed false if  there aren't restrictions or an object with the restriction information
2856       * @since  Moodle 3.3
2857       */
2858      public function get_time_restriction_status() {
2859          if ($this->can_manage()) {
2860              return false;
2861          }
2862  
2863          if (!$this->is_accessible()) {
2864              if ($this->properties->deadline != 0 && time() > $this->properties->deadline) {
2865                  $status = ['reason' => 'lessonclosed', 'time' => $this->properties->deadline];
2866              } else {
2867                  $status = ['reason' => 'lessonopen', 'time' => $this->properties->available];
2868              }
2869              return (object) $status;
2870          }
2871          return false;
2872      }
2873  
2874      /**
2875       * Check if password restriction is applied.
2876       *
2877       * @param string $userpassword the user password to check (if the restriction is set)
2878       * @return mixed false if there aren't restrictions or an object with the restriction information
2879       * @since  Moodle 3.3
2880       */
2881      public function get_password_restriction_status($userpassword) {
2882          global $USER;
2883          if ($this->can_manage()) {
2884              return false;
2885          }
2886  
2887          if ($this->properties->usepassword && empty($USER->lessonloggedin[$this->id])) {
2888              $correctpass = false;
2889              if (!empty($userpassword) &&
2890                      (($this->properties->password == md5(trim($userpassword))) || ($this->properties->password == trim($userpassword)))) {
2891                  // With or without md5 for backward compatibility (MDL-11090).
2892                  $correctpass = true;
2893                  $USER->lessonloggedin[$this->id] = true;
2894              } else if (isset($this->properties->extrapasswords)) {
2895                  // Group overrides may have additional passwords.
2896                  foreach ($this->properties->extrapasswords as $password) {
2897                      if (strcmp($password, md5(trim($userpassword))) === 0 || strcmp($password, trim($userpassword)) === 0) {
2898                          $correctpass = true;
2899                          $USER->lessonloggedin[$this->id] = true;
2900                      }
2901                  }
2902              }
2903              return !$correctpass;
2904          }
2905          return false;
2906      }
2907  
2908      /**
2909       * Check if dependencies restrictions are applied.
2910       *
2911       * @return mixed false if there aren't restrictions or an object with the restriction information
2912       * @since  Moodle 3.3
2913       */
2914      public function get_dependencies_restriction_status() {
2915          global $DB, $USER;
2916          if ($this->can_manage()) {
2917              return false;
2918          }
2919  
2920          if ($dependentlesson = $DB->get_record('lesson', array('id' => $this->properties->dependency))) {
2921              // Lesson exists, so we can proceed.
2922              $conditions = unserialize_object($this->properties->conditions);
2923              // Assume false for all.
2924              $errors = array();
2925              // Check for the timespent condition.
2926              if (!empty($conditions->timespent)) {
2927                  $timespent = false;
2928                  if ($attempttimes = $DB->get_records('lesson_timer', array("userid" => $USER->id, "lessonid" => $dependentlesson->id))) {
2929                      // Go through all the times and test to see if any of them satisfy the condition.
2930                      foreach ($attempttimes as $attempttime) {
2931                          $duration = $attempttime->lessontime - $attempttime->starttime;
2932                          if ($conditions->timespent < $duration / 60) {
2933                              $timespent = true;
2934                          }
2935                      }
2936                  }
2937                  if (!$timespent) {
2938                      $errors[] = get_string('timespenterror', 'lesson', $conditions->timespent);
2939                  }
2940              }
2941              // Check for the gradebetterthan condition.
2942              if (!empty($conditions->gradebetterthan)) {
2943                  $gradebetterthan = false;
2944                  if ($studentgrades = $DB->get_records('lesson_grades', array("userid" => $USER->id, "lessonid" => $dependentlesson->id))) {
2945                      // Go through all the grades and test to see if any of them satisfy the condition.
2946                      foreach ($studentgrades as $studentgrade) {
2947                          if ($studentgrade->grade >= $conditions->gradebetterthan) {
2948                              $gradebetterthan = true;
2949                          }
2950                      }
2951                  }
2952                  if (!$gradebetterthan) {
2953                      $errors[] = get_string('gradebetterthanerror', 'lesson', $conditions->gradebetterthan);
2954                  }
2955              }
2956              // Check for the completed condition.
2957              if (!empty($conditions->completed)) {
2958                  if (!$DB->count_records('lesson_grades', array('userid' => $USER->id, 'lessonid' => $dependentlesson->id))) {
2959                      $errors[] = get_string('completederror', 'lesson');
2960                  }
2961              }
2962              if (!empty($errors)) {
2963                  return (object) ['errors' => $errors, 'dependentlesson' => $dependentlesson];
2964              }
2965          }
2966          return false;
2967      }
2968  
2969      /**
2970       * Check if the lesson is in review mode. (The user already finished it and retakes are not allowed).
2971       *
2972       * @return bool true if is in review mode
2973       * @since  Moodle 3.3
2974       */
2975      public function is_in_review_mode() {
2976          global $DB, $USER;
2977  
2978          $userhasgrade = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id));
2979          if ($userhasgrade && !$this->properties->retake) {
2980              return true;
2981          }
2982          return false;
2983      }
2984  
2985      /**
2986       * Return the last page the current user saw.
2987       *
2988       * @param int $retriescount the number of retries for the lesson (the last retry number).
2989       * @return mixed false if the user didn't see the lesson or the last page id
2990       */
2991      public function get_last_page_seen($retriescount) {
2992          global $DB, $USER;
2993  
2994          $lastpageseen = false;
2995          $allattempts = $this->get_attempts($retriescount);
2996          if (!empty($allattempts)) {
2997              $attempt = end($allattempts);
2998              $attemptpage = $this->load_page($attempt->pageid);
2999              $jumpto = $DB->get_field('lesson_answers', 'jumpto', array('id' => $attempt->answerid));
3000              // Convert the jumpto to a proper page id.
3001              if ($jumpto == 0) {
3002                  // Check if a question has been incorrectly answered AND no more attempts at it are left.
3003                  $nattempts = $this->get_attempts($attempt->retry, false, $attempt->pageid, $USER->id);
3004                  if (count($nattempts) >= $this->properties->maxattempts) {
3005                      $lastpageseen = $this->get_next_page($attemptpage->nextpageid);
3006                  } else {
3007                      $lastpageseen = $attempt->pageid;
3008                  }
3009              } else if ($jumpto == LESSON_NEXTPAGE) {
3010                  $lastpageseen = $this->get_next_page($attemptpage->nextpageid);
3011              } else if ($jumpto == LESSON_CLUSTERJUMP) {
3012                  $lastpageseen = $this->cluster_jump($attempt->pageid);
3013              } else {
3014                  $lastpageseen = $jumpto;
3015              }
3016          }
3017  
3018          if ($branchtables = $this->get_content_pages_viewed($retriescount, $USER->id, 'timeseen DESC')) {
3019              // In here, user has viewed a branch table.
3020              $lastbranchtable = current($branchtables);
3021              if (count($allattempts) > 0) {
3022                  if ($lastbranchtable->timeseen > $attempt->timeseen) {
3023                      // This branch table was viewed more recently than the question page.
3024                      if (!empty($lastbranchtable->nextpageid)) {
3025                          $lastpageseen = $lastbranchtable->nextpageid;
3026                      } else {
3027                          // Next page ID did not exist prior to MDL-34006.
3028                          $lastpageseen = $lastbranchtable->pageid;
3029                      }
3030                  }
3031              } else {
3032                  // Has not answered any questions but has viewed a branch table.
3033                  if (!empty($lastbranchtable->nextpageid)) {
3034                      $lastpageseen = $lastbranchtable->nextpageid;
3035                  } else {
3036                      // Next page ID did not exist prior to MDL-34006.
3037                      $lastpageseen = $lastbranchtable->pageid;
3038                  }
3039              }
3040          }
3041          return $lastpageseen;
3042      }
3043  
3044      /**
3045       * Return the number of retries in a lesson for a given user.
3046       *
3047       * @param  int $userid the user id
3048       * @return int the retries count
3049       * @since  Moodle 3.3
3050       */
3051      public function count_user_retries($userid) {
3052          global $DB;
3053  
3054          return $DB->count_records('lesson_grades', array("lessonid" => $this->properties->id, "userid" => $userid));
3055      }
3056  
3057      /**
3058       * Check if a user left a timed session.
3059       *
3060       * @param int $retriescount the number of retries for the lesson (the last retry number).
3061       * @return true if the user left the timed session
3062       * @since  Moodle 3.3
3063       */
3064      public function left_during_timed_session($retriescount) {
3065          global $DB, $USER;
3066  
3067          $conditions = array('lessonid' => $this->properties->id, 'userid' => $USER->id, 'retry' => $retriescount);
3068          return $DB->count_records('lesson_attempts', $conditions) > 0 || $DB->count_records('lesson_branch', $conditions) > 0;
3069      }
3070  
3071      /**
3072       * Trigger module viewed event and set the module viewed for completion.
3073       *
3074       * @since  Moodle 3.3
3075       */
3076      public function set_module_viewed() {
3077          global $CFG;
3078          require_once($CFG->libdir . '/completionlib.php');
3079  
3080          // Trigger module viewed event.
3081          $event = \mod_lesson\event\course_module_viewed::create(array(
3082              'objectid' => $this->properties->id,
3083              'context' => $this->get_context()
3084          ));
3085          $event->add_record_snapshot('course_modules', $this->get_cm());
3086          $event->add_record_snapshot('course', $this->get_courserecord());
3087          $event->trigger();
3088  
3089          // Mark as viewed.
3090          $completion = new completion_info($this->get_courserecord());
3091          $completion->set_module_viewed($this->get_cm());
3092      }
3093  
3094      /**
3095       * Return the timers in the current lesson for the given user.
3096       *
3097       * @param  int      $userid    the user id
3098       * @param  string   $sort      an order to sort the results in (optional, a valid SQL ORDER BY parameter).
3099       * @param  string   $fields    a comma separated list of fields to return
3100       * @param  int      $limitfrom return a subset of records, starting at this point (optional).
3101       * @param  int      $limitnum  return a subset comprising this many records in total (optional, required if $limitfrom is set).
3102       * @return array    list of timers for the given user in the lesson
3103       * @since  Moodle 3.3
3104       */
3105      public function get_user_timers($userid = null, $sort = '', $fields = '*', $limitfrom = 0, $limitnum = 0) {
3106          global $DB, $USER;
3107  
3108          if ($userid === null) {
3109              $userid = $USER->id;
3110          }
3111  
3112          $params = array('lessonid' => $this->properties->id, 'userid' => $userid);
3113          return $DB->get_records('lesson_timer', $params, $sort, $fields, $limitfrom, $limitnum);
3114      }
3115  
3116      /**
3117       * Check if the user is out of time in a timed lesson.
3118       *
3119       * @param  stdClass $timer timer object
3120       * @return bool True if the user is on time, false is the user ran out of time
3121       * @since  Moodle 3.3
3122       */
3123      public function check_time($timer) {
3124          if ($this->properties->timelimit) {
3125              $timeleft = $timer->starttime + $this->properties->timelimit - time();
3126              if ($timeleft <= 0) {
3127                  // Out of time.
3128                  $this->add_message(get_string('eolstudentoutoftime', 'lesson'));
3129                  return false;
3130              } else if ($timeleft < 60) {
3131                  // One minute warning.
3132                  $this->add_message(get_string('studentoneminwarning', 'lesson'));
3133              }
3134          }
3135          return true;
3136      }
3137  
3138      /**
3139       * Add different informative messages to the given page.
3140       *
3141       * @param lesson_page $page page object
3142       * @param reviewmode $bool whether we are in review mode or not
3143       * @since  Moodle 3.3
3144       */
3145      public function add_messages_on_page_view(lesson_page $page, $reviewmode) {
3146          global $DB, $USER;
3147  
3148          if (!$this->can_manage()) {
3149              if ($page->qtype == LESSON_PAGE_BRANCHTABLE && $this->properties->minquestions) {
3150                  // Tell student how many questions they have seen, how many are required and their grade.
3151                  $ntries = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id));
3152                  $gradeinfo = lesson_grade($this, $ntries);
3153                  if ($gradeinfo->attempts) {
3154                      if ($gradeinfo->nquestions < $this->properties->minquestions) {
3155                          $a = new stdClass;
3156                          $a->nquestions   = $gradeinfo->nquestions;
3157                          $a->minquestions = $this->properties->minquestions;
3158                          $this->add_message(get_string('numberofpagesviewednotice', 'lesson', $a));
3159                      }
3160  
3161                      if (!$reviewmode && $this->properties->ongoing) {
3162                          $this->add_message(get_string("numberofcorrectanswers", "lesson", $gradeinfo->earned), 'notify');
3163                          if ($this->properties->grade != GRADE_TYPE_NONE) {
3164                              $a = new stdClass;
3165                              $a->grade = format_float($gradeinfo->grade * $this->properties->grade / 100, 1);
3166                              $a->total = $this->properties->grade;
3167                              $this->add_message(get_string('yourcurrentgradeisoutof', 'lesson', $a), 'notify');
3168                          }
3169                      }
3170                  }
3171              }
3172          } else {
3173              if ($this->properties->timelimit) {
3174                  $this->add_message(get_string('teachertimerwarning', 'lesson'));
3175              }
3176              if (lesson_display_teacher_warning($this)) {
3177                  // This is the warning msg for teachers to inform them that cluster
3178                  // and unseen does not work while logged in as a teacher.
3179                  $warningvars = new stdClass();
3180                  $warningvars->cluster = get_string('clusterjump', 'lesson');
3181                  $warningvars->unseen = get_string('unseenpageinbranch', 'lesson');
3182                  $this->add_message(get_string('teacherjumpwarning', 'lesson', $warningvars));
3183              }
3184          }
3185      }
3186  
3187      /**
3188       * Get the ongoing score message for the user (depending on the user permission and lesson settings).
3189       *
3190       * @return str the ongoing score message
3191       * @since  Moodle 3.3
3192       */
3193      public function get_ongoing_score_message() {
3194          global $USER, $DB;
3195  
3196          $context = $this->get_context();
3197  
3198          if (has_capability('mod/lesson:manage', $context)) {
3199              return get_string('teacherongoingwarning', 'lesson');
3200          } else {
3201              $ntries = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id));
3202              if (isset($USER->modattempts[$this->properties->id])) {
3203                  $ntries--;
3204              }
3205              $gradeinfo = lesson_grade($this, $ntries);
3206              $a = new stdClass;
3207              if ($this->properties->custom) {
3208                  $a->score = $gradeinfo->earned;
3209                  $a->currenthigh = $gradeinfo->total;
3210                  return get_string("ongoingcustom", "lesson", $a);
3211              } else {
3212                  $a->correct = $gradeinfo->earned;
3213                  $a->viewed = $gradeinfo->attempts;
3214                  return get_string("ongoingnormal", "lesson", $a);
3215              }
3216          }
3217      }
3218  
3219      /**
3220       * Calculate the progress of the current user in the lesson.
3221       *
3222       * @return int the progress (scale 0-100)
3223       * @since  Moodle 3.3
3224       */
3225      public function calculate_progress() {
3226          global $USER, $DB;
3227  
3228          // Check if the user is reviewing the attempt.
3229          if (isset($USER->modattempts[$this->properties->id])) {
3230              return 100;
3231          }
3232  
3233          // All of the lesson pages.
3234          $pages = $this->load_all_pages();
3235          foreach ($pages as $page) {
3236              if ($page->prevpageid == 0) {
3237                  $pageid = $page->id;  // Find the first page id.
3238                  break;
3239              }
3240          }
3241  
3242          // Current attempt number.
3243          if (!$ntries = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id))) {
3244              $ntries = 0;  // May not be necessary.
3245          }
3246  
3247          $viewedpageids = array();
3248          if ($attempts = $this->get_attempts($ntries, false)) {
3249              foreach ($attempts as $attempt) {
3250                  $viewedpageids[$attempt->pageid] = $attempt;
3251              }
3252          }
3253  
3254          $viewedbranches = array();
3255          // Collect all of the branch tables viewed.
3256          if ($branches = $this->get_content_pages_viewed($ntries, $USER->id, 'timeseen ASC', 'id, pageid')) {
3257              foreach ($branches as $branch) {
3258                  $viewedbranches[$branch->pageid] = $branch;
3259              }
3260              $viewedpageids = array_merge($viewedpageids, $viewedbranches);
3261          }
3262  
3263          // Filter out the following pages:
3264          // - End of Cluster
3265          // - End of Branch
3266          // - Pages found inside of Clusters
3267          // Do not filter out Cluster Page(s) because we count a cluster as one.
3268          // By keeping the cluster page, we get our 1.
3269          $validpages = array();
3270          while ($pageid != 0) {
3271              $pageid = $pages[$pageid]->valid_page_and_view($validpages, $viewedpageids);
3272          }
3273  
3274          // Progress calculation as a percent.
3275          $progress = round(count($viewedpageids) / count($validpages), 2) * 100;
3276          return (int) $progress;
3277      }
3278  
3279      /**
3280       * Calculate the correct page and prepare contents for a given page id (could be a page jump id).
3281       *
3282       * @param  int $pageid the given page id
3283       * @param  mod_lesson_renderer $lessonoutput the lesson output rendered
3284       * @param  bool $reviewmode whether we are in review mode or not
3285       * @param  bool $redirect  Optional, default to true. Set to false to avoid redirection and return the page to redirect.
3286       * @return array the page object and contents
3287       * @throws moodle_exception
3288       * @since  Moodle 3.3
3289       */
3290      public function prepare_page_and_contents($pageid, $lessonoutput, $reviewmode, $redirect = true) {
3291          global $USER, $CFG;
3292  
3293          $page = $this->load_page($pageid);
3294          // Check if the page is of a special type and if so take any nessecary action.
3295          $newpageid = $page->callback_on_view($this->can_manage(), $redirect);
3296  
3297          // Avoid redirections returning the jump to special page id.
3298          if (!$redirect && is_numeric($newpageid) && $newpageid < 0) {
3299              return array($newpageid, null, null);
3300          }
3301  
3302          if (is_numeric($newpageid)) {
3303              $page = $this->load_page($newpageid);
3304          }
3305  
3306          // Add different informative messages to the given page.
3307          $this->add_messages_on_page_view($page, $reviewmode);
3308  
3309          if (is_array($page->answers) && count($page->answers) > 0) {
3310              // This is for modattempts option.  Find the users previous answer to this page,
3311              // and then display it below in answer processing.
3312              if (isset($USER->modattempts[$this->properties->id])) {
3313                  $retries = $this->count_user_retries($USER->id);
3314                  if (!$attempts = $this->get_attempts($retries - 1, false, $page->id)) {
3315                      throw new moodle_exception('cannotfindpreattempt', 'lesson');
3316                  }
3317                  $attempt = end($attempts);
3318                  $USER->modattempts[$this->properties->id] = $attempt;
3319              } else {
3320                  $attempt = false;
3321              }
3322              $lessoncontent = $lessonoutput->display_page($this, $page, $attempt);
3323          } else {
3324              require_once($CFG->dirroot . '/mod/lesson/view_form.php');
3325              $data = new stdClass;
3326              $data->id = $this->get_cm()->id;
3327              $data->pageid = $page->id;
3328              $data->newpageid = $this->get_next_page($page->nextpageid);
3329  
3330              $customdata = array(
3331                  'title'     => $page->title,
3332                  'contents'  => $page->get_contents()
3333              );
3334              $mform = new lesson_page_without_answers($CFG->wwwroot.'/mod/lesson/continue.php', $customdata);
3335              $mform->set_data($data);
3336              ob_start();
3337              $mform->display();
3338              $lessoncontent = ob_get_contents();
3339              ob_end_clean();
3340          }
3341  
3342          return array($page->id, $page, $lessoncontent);
3343      }
3344  
3345      /**
3346       * This returns a real page id to jump to (or LESSON_EOL) after processing page responses.
3347       *
3348       * @param  lesson_page $page      lesson page
3349       * @param  int         $newpageid the new page id
3350       * @return int the real page to jump to (or end of lesson)
3351       * @since  Moodle 3.3
3352       */
3353      public function calculate_new_page_on_jump(lesson_page $page, $newpageid) {
3354          global $USER, $DB;
3355  
3356          $canmanage = $this->can_manage();
3357  
3358          if (isset($USER->modattempts[$this->properties->id])) {
3359              // Make sure if the student is reviewing, that he/she sees the same pages/page path that he/she saw the first time.
3360              if ($USER->modattempts[$this->properties->id]->pageid == $page->id && $page->nextpageid == 0) {
3361                  // Remember, this session variable holds the pageid of the last page that the user saw.
3362                  $newpageid = LESSON_EOL;
3363              } else {
3364                  $nretakes = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id));
3365                  $nretakes--; // Make sure we are looking at the right try.
3366                  $attempts = $DB->get_records("lesson_attempts", array("lessonid" => $this->properties->id, "userid" => $USER->id, "retry" => $nretakes), "timeseen", "id, pageid");
3367                  $found = false;
3368                  $temppageid = 0;
3369                  // Make sure that the newpageid always defaults to something valid.
3370                  $newpageid = LESSON_EOL;
3371                  foreach ($attempts as $attempt) {
3372                      if ($found && $temppageid != $attempt->pageid) {
3373                          // Now try to find the next page, make sure next few attempts do no belong to current page.
3374                          $newpageid = $attempt->pageid;
3375                          break;
3376                      }
3377                      if ($attempt->pageid == $page->id) {
3378                          $found = true; // If found current page.
3379                          $temppageid = $attempt->pageid;
3380                      }
3381                  }
3382              }
3383          } else if ($newpageid != LESSON_CLUSTERJUMP && $page->id != 0 && $newpageid > 0) {
3384              // Going to check to see if the page that the user is going to view next, is a cluster page.
3385              // If so, dont display, go into the cluster.
3386              // The $newpageid > 0 is used to filter out all of the negative code jumps.
3387              $newpage = $this->load_page($newpageid);
3388              if ($overridenewpageid = $newpage->override_next_page($newpageid)) {
3389                  $newpageid = $overridenewpageid;
3390              }
3391          } else if ($newpageid == LESSON_UNSEENBRANCHPAGE) {
3392              if ($canmanage) {
3393                  if ($page->nextpageid == 0) {
3394                      $newpageid = LESSON_EOL;
3395                  } else {
3396                      $newpageid = $page->nextpageid;
3397                  }
3398              } else {
3399                  $newpageid = lesson_unseen_question_jump($this, $USER->id, $page->id);
3400              }
3401          } else if ($newpageid == LESSON_PREVIOUSPAGE) {
3402              $newpageid = $page->prevpageid;
3403          } else if ($newpageid == LESSON_RANDOMPAGE) {
3404              $newpageid = lesson_random_question_jump($this, $page->id);
3405          } else if ($newpageid == LESSON_CLUSTERJUMP) {
3406              if ($canmanage) {
3407                  if ($page->nextpageid == 0) {  // If teacher, go to next page.
3408                      $newpageid = LESSON_EOL;
3409                  } else {
3410                      $newpageid = $page->nextpageid;
3411                  }
3412              } else {
3413                  $newpageid = $this->cluster_jump($page->id);
3414              }
3415          } else if ($newpageid == 0) {
3416              $newpageid = $page->id;
3417          } else if ($newpageid == LESSON_NEXTPAGE) {
3418              $newpageid = $this->get_next_page($page->nextpageid);
3419          }
3420  
3421          return $newpageid;
3422      }
3423  
3424      /**
3425       * Process page responses.
3426       *
3427       * @param lesson_page $page page object
3428       * @since  Moodle 3.3
3429       */
3430      public function process_page_responses(lesson_page $page) {
3431          $context = $this->get_context();
3432  
3433          // Check the page has answers [MDL-25632].
3434          if (count($page->answers) > 0) {
3435              $result = $page->record_attempt($context);
3436          } else {
3437              // The page has no answers so we will just progress to the next page in the
3438              // sequence (as set by newpageid).
3439              $result = new stdClass;
3440              $result->newpageid       = optional_param('newpageid', $page->nextpageid, PARAM_INT);
3441              $result->nodefaultresponse  = true;
3442              $result->inmediatejump = false;
3443          }
3444  
3445          if ($result->inmediatejump) {
3446              return $result;
3447          }
3448  
3449          $result->newpageid = $this->calculate_new_page_on_jump($page, $result->newpageid);
3450  
3451          return $result;
3452      }
3453  
3454      /**
3455       * Add different informative messages to the given page.
3456       *
3457       * @param lesson_page $page page object
3458       * @param stdClass $result the page processing result object
3459       * @param bool $reviewmode whether we are in review mode or not
3460       * @since  Moodle 3.3
3461       */
3462      public function add_messages_on_page_process(lesson_page $page, $result, $reviewmode) {
3463  
3464          if ($this->can_manage()) {
3465              // This is the warning msg for teachers to inform them that cluster and unseen does not work while logged in as a teacher.
3466              if (lesson_display_teacher_warning($this)) {
3467                  $warningvars = new stdClass();
3468                  $warningvars->cluster = get_string("clusterjump", "lesson");
3469                  $warningvars->unseen = get_string("unseenpageinbranch", "lesson");
3470                  $this->add_message(get_string("teacherjumpwarning", "lesson", $warningvars));
3471              }
3472              // Inform teacher that s/he will not see the timer.
3473              if ($this->properties->timelimit) {
3474                  $this->add_message(get_string("teachertimerwarning", "lesson"));
3475              }
3476          }
3477          // Report attempts remaining.
3478          if ($result->attemptsremaining != 0 && $this->properties->review && !$reviewmode) {
3479              $this->add_message(get_string('attemptsremaining', 'lesson', $result->attemptsremaining));
3480          }
3481      }
3482  
3483      /**
3484       * Process and return all the information for the end of lesson page.
3485       *
3486       * @param string $outoftime used to check to see if the student ran out of time
3487       * @return stdclass an object with all the page data ready for rendering
3488       * @since  Moodle 3.3
3489       */
3490      public function process_eol_page($outoftime) {
3491          global $DB, $USER;
3492  
3493          $course = $this->get_courserecord();
3494          $cm = $this->get_cm();
3495          $canmanage = $this->can_manage();
3496  
3497          // Init all the possible fields and values.
3498          $data = (object) array(
3499              'gradelesson' => true,
3500              'notenoughtimespent' => false,
3501              'numberofpagesviewed' => false,
3502              'youshouldview' => false,
3503              'numberofcorrectanswers' => false,
3504              'displayscorewithessays' => false,
3505              'displayscorewithoutessays' => false,
3506              'yourcurrentgradeisoutof' => false,
3507              'yourcurrentgradeis' => false,
3508              'eolstudentoutoftimenoanswers' => false,
3509              'welldone' => false,
3510              'progressbar' => false,
3511              'displayofgrade' => false,
3512              'reviewlesson' => false,
3513              'modattemptsnoteacher' => false,
3514              'activitylink' => false,
3515              'progresscompleted' => false,
3516          );
3517  
3518          $ntries = $DB->count_records("lesson_grades", array("lessonid" => $this->properties->id, "userid" => $USER->id));
3519          if (isset($USER->modattempts[$this->properties->id])) {
3520              $ntries--;  // Need to look at the old attempts :).
3521          }
3522  
3523          $gradeinfo = lesson_grade($this, $ntries);
3524          $data->gradeinfo = $gradeinfo;
3525          if ($this->properties->custom && !$canmanage) {
3526              // Before we calculate the custom score make sure they answered the minimum
3527              // number of questions. We only need to do this for custom scoring as we can
3528              // not get the miniumum score the user should achieve. If we are not using
3529              // custom scoring (so all questions are valued as 1) then we simply check if
3530              // they answered more than the minimum questions, if not, we mark it out of the
3531              // number specified in the minimum questions setting - which is done in lesson_grade().
3532              // Get the number of answers given.
3533              if ($gradeinfo->nquestions < $this->properties->minquestions) {
3534                  $data->gradelesson = false;
3535                  $a = new stdClass;
3536                  $a->nquestions = $gradeinfo->nquestions;
3537                  $a->minquestions = $this->properties->minquestions;
3538                  $this->add_message(get_string('numberofpagesviewednotice', 'lesson', $a));
3539              }
3540          }
3541  
3542          if (!$canmanage) {
3543              if ($data->gradelesson) {
3544                  // Store this now before any modifications to pages viewed.
3545                  $progresscompleted = $this->calculate_progress();
3546  
3547                  // Update the clock / get time information for this user.
3548                  $this->stop_timer();
3549  
3550                  // Update completion state.
3551                  $completion = new completion_info($course);
3552                  if ($completion->is_enabled($cm) && $this->properties->completionendreached) {
3553                      $completion->update_state($cm, COMPLETION_COMPLETE);
3554                  }
3555  
3556                  if ($this->properties->completiontimespent > 0) {
3557                      $duration = $DB->get_field_sql(
3558                          "SELECT SUM(lessontime - starttime)
3559                                         FROM {lesson_timer}
3560                                        WHERE lessonid = :lessonid
3561                                          AND userid = :userid",
3562                          array('userid' => $USER->id, 'lessonid' => $this->properties->id));
3563                      if (!$duration) {
3564                          $duration = 0;
3565                      }
3566  
3567                      // If student has not spend enough time in the lesson, display a message.
3568                      if ($duration < $this->properties->completiontimespent) {
3569                          $a = new stdClass;
3570                          $a->timespentraw = $duration;
3571                          $a->timespent = format_time($duration);
3572                          $a->timerequiredraw = $this->properties->completiontimespent;
3573                          $a->timerequired = format_time($this->properties->completiontimespent);
3574                          $data->notenoughtimespent = $a;
3575                      }
3576                  }
3577  
3578                  if ($gradeinfo->attempts) {
3579                      if (!$this->properties->custom) {
3580                          $data->numberofpagesviewed = $gradeinfo->nquestions;
3581                          if ($this->properties->minquestions) {
3582                              if ($gradeinfo->nquestions < $this->properties->minquestions) {
3583                                  $data->youshouldview = $this->properties->minquestions;
3584                              }
3585                          }
3586                          $data->numberofcorrectanswers = $gradeinfo->earned;
3587                      }
3588                      $a = new stdClass;
3589                      $a->score = $gradeinfo->earned;
3590                      $a->grade = $gradeinfo->total;
3591                      if ($gradeinfo->nmanual) {
3592                          $a->tempmaxgrade = $gradeinfo->total - $gradeinfo->manualpoints;
3593                          $a->essayquestions = $gradeinfo->nmanual;
3594                          $data->displayscorewithessays = $a;
3595                      } else {
3596                          $data->displayscorewithoutessays = $a;
3597                      }
3598  
3599                      $grade = new stdClass();
3600                      $grade->lessonid = $this->properties->id;
3601                      $grade->userid = $USER->id;
3602                      $grade->grade = $gradeinfo->grade;
3603                      $grade->completed = time();
3604                      if (isset($USER->modattempts[$this->properties->id])) { // If reviewing, make sure update old grade record.
3605                          if (!$grades = $DB->get_records("lesson_grades",
3606                              array("lessonid" => $this->properties->id, "userid" => $USER->id), "completed DESC", '*', 0, 1)) {
3607                              throw new moodle_exception('cannotfindgrade', 'lesson');
3608                          }
3609                          $oldgrade = array_shift($grades);
3610                          $grade->id = $oldgrade->id;
3611                          $DB->update_record("lesson_grades", $grade);
3612                      } else {
3613                          $newgradeid = $DB->insert_record("lesson_grades", $grade);
3614                      }
3615  
3616                      // Update central gradebook.
3617                      lesson_update_grades($this, $USER->id);
3618  
3619                      // Print grade (grade type Point).
3620                      if ($this->properties->grade > 0) {
3621                          $a = new stdClass;
3622                          $a->grade = format_float($gradeinfo->grade * $this->properties->grade / 100, 1);
3623                          $a->total = $this->properties->grade;
3624                          $data->yourcurrentgradeisoutof = $a;
3625                      }
3626  
3627                      // Print grade (grade type Scale).
3628                      if ($this->properties->grade < 0) {
3629                          // Grade type is Scale.
3630                          $grades = grade_get_grades($course->id, 'mod', 'lesson', $cm->instance, $USER->id);
3631                          $grade = reset($grades->items[0]->grades);
3632                          $data->yourcurrentgradeis = $grade->str_grade;
3633                      }
3634                  } else {
3635                      if ($this->properties->timelimit) {
3636                          if ($outoftime == 'normal') {
3637                              $grade = new stdClass();
3638                              $grade->lessonid = $this->properties->id;
3639                              $grade->userid = $USER->id;
3640                              $grade->grade = 0;
3641                              $grade->completed = time();
3642                              $newgradeid = $DB->insert_record("lesson_grades", $grade);
3643                              $data->eolstudentoutoftimenoanswers = true;
3644  
3645                              // Update central gradebook.
3646                              lesson_update_grades($this, $USER->id);
3647                          }
3648                      } else {
3649                          $data->welldone = true;
3650                      }
3651                  }
3652  
3653                  $data->progresscompleted = $progresscompleted;
3654              }
3655          } else {
3656              // Display for teacher.
3657              if ($this->properties->grade != GRADE_TYPE_NONE) {
3658                  $data->displayofgrade = true;
3659              }
3660          }
3661  
3662          if ($this->properties->modattempts && !$canmanage) {
3663              // Make sure if the student is reviewing, that he/she sees the same pages/page path that he/she saw the first time
3664              // look at the attempt records to find the first QUESTION page that the user answered, then use that page id
3665              // to pass to view again.  This is slick cause it wont call the empty($pageid) code
3666              // $ntries is decremented above.
3667              if (!$attempts = $this->get_attempts($ntries)) {
3668                  $attempts = array();
3669                  $url = new moodle_url('/mod/lesson/view.php', array('id' => $cm->id));
3670              } else {
3671                  $firstattempt = current($attempts);
3672                  $pageid = $firstattempt->pageid;
3673                  // If the student wishes to review, need to know the last question page that the student answered.
3674                  // This will help to make sure that the student can leave the lesson via pushing the continue button.
3675                  $lastattempt = end($attempts);
3676                  $USER->modattempts[$this->properties->id] = $lastattempt->pageid;
3677  
3678                  $url = new moodle_url('/mod/lesson/view.php', array('id' => $cm->id, 'pageid' => $pageid));
3679              }
3680              $data->reviewlesson = $url->out(false);
3681          } else if ($this->properties->modattempts && $canmanage) {
3682              $data->modattemptsnoteacher = true;
3683          }
3684  
3685          if ($this->properties->activitylink) {
3686              $data->activitylink = $this->link_for_activitylink();
3687          }
3688          return $data;
3689      }
3690  
3691      /**
3692       * Returns the last "legal" attempt from the list of student attempts.
3693       *
3694       * @param array $attempts The list of student attempts.
3695       * @return stdClass The updated fom data.
3696       */
3697      public function get_last_attempt(array $attempts): stdClass {
3698          // If there are more tries than the max that is allowed, grab the last "legal" attempt.
3699          if (!empty($this->maxattempts) && (count($attempts) > $this->maxattempts)) {
3700              $lastattempt = $attempts[$this->maxattempts - 1];
3701          } else {
3702              // Grab the last attempt since there's no limit to the max attempts or the user has made fewer attempts than the max.
3703              $lastattempt = end($attempts);
3704          }
3705          return $lastattempt;
3706      }
3707  }
3708  
3709  
3710  /**
3711   * Abstract class to provide a core functions to the all lesson classes
3712   *
3713   * This class should be abstracted by ALL classes with the lesson module to ensure
3714   * that all classes within this module can be interacted with in the same way.
3715   *
3716   * This class provides the user with a basic properties array that can be fetched
3717   * or set via magic methods, or alternatively by defining methods get_blah() or
3718   * set_blah() within the extending object.
3719   *
3720   * @copyright  2009 Sam Hemelryk
3721   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3722   */
3723  abstract class lesson_base {
3724  
3725      /**
3726       * An object containing properties
3727       * @var stdClass
3728       */
3729      protected $properties;
3730  
3731      /**
3732       * The constructor
3733       * @param stdClass $properties
3734       */
3735      public function __construct($properties) {
3736          $this->properties = (object)$properties;
3737      }
3738  
3739      /**
3740       * Magic property method
3741       *
3742       * Attempts to call a set_$key method if one exists otherwise falls back
3743       * to simply set the property
3744       *
3745       * @param string $key
3746       * @param mixed $value
3747       */
3748      public function __set($key, $value) {
3749          if (method_exists($this, 'set_'.$key)) {
3750              $this->{'set_'.$key}($value);
3751          }
3752          $this->properties->{$key} = $value;
3753      }
3754  
3755      /**
3756       * Magic get method
3757       *
3758       * Attempts to call a get_$key method to return the property and ralls over
3759       * to return the raw property
3760       *
3761       * @param str $key
3762       * @return mixed
3763       */
3764      public function __get($key) {
3765          if (method_exists($this, 'get_'.$key)) {
3766              return $this->{'get_'.$key}();
3767          }
3768          return $this->properties->{$key};
3769      }
3770  
3771      /**
3772       * Stupid PHP needs an isset magic method if you use the get magic method and
3773       * still want empty calls to work.... blah ~!
3774       *
3775       * @param string $key
3776       * @return bool
3777       */
3778      public function __isset($key) {
3779          if (method_exists($this, 'get_'.$key)) {
3780              $val = $this->{'get_'.$key}();
3781              return !empty($val);
3782          }
3783          return !empty($this->properties->{$key});
3784      }
3785  
3786      //NOTE: E_STRICT does not allow to change function signature!
3787  
3788      /**
3789       * If implemented should create a new instance, save it in the DB and return it
3790       */
3791      //public static function create() {}
3792      /**
3793       * If implemented should load an instance from the DB and return it
3794       */
3795      //public static function load() {}
3796      /**
3797       * Fetches all of the properties of the object
3798       * @return stdClass
3799       */
3800      public function properties() {
3801          return $this->properties;
3802      }
3803  }
3804  
3805  
3806  /**
3807   * Abstract class representation of a page associated with a lesson.
3808   *
3809   * This class should MUST be extended by all specialised page types defined in
3810   * mod/lesson/pagetypes/.
3811   * There are a handful of abstract methods that need to be defined as well as
3812   * severl methods that can optionally be defined in order to make the page type
3813   * operate in the desired way
3814   *
3815   * Database properties
3816   * @property int $id The id of this lesson page
3817   * @property int $lessonid The id of the lesson this page belongs to
3818   * @property int $prevpageid The id of the page before this one
3819   * @property int $nextpageid The id of the next page in the page sequence
3820   * @property int $qtype Identifies the page type of this page
3821   * @property int $qoption Used to record page type specific options
3822   * @property int $layout Used to record page specific layout selections
3823   * @property int $display Used to record page specific display selections
3824   * @property int $timecreated Timestamp for when the page was created
3825   * @property int $timemodified Timestamp for when the page was last modified
3826   * @property string $title The title of this page
3827   * @property string $contents The rich content shown to describe the page
3828   * @property int $contentsformat The format of the contents field
3829   *
3830   * Calculated properties
3831   * @property-read array $answers An array of answers for this page
3832   * @property-read bool $displayinmenublock Toggles display in the left menu block
3833   * @property-read array $jumps An array containing all the jumps this page uses
3834   * @property-read lesson $lesson The lesson this page belongs to
3835   * @property-read int $type The type of the page [question | structure]
3836   * @property-read typeid The unique identifier for the page type
3837   * @property-read typestring The string that describes this page type
3838   *
3839   * @abstract
3840   * @copyright  2009 Sam Hemelryk
3841   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
3842   */
3843  abstract class lesson_page extends lesson_base {
3844  
3845      /**
3846       * A reference to the lesson this page belongs to
3847       * @var lesson
3848       */
3849      protected $lesson = null;
3850      /**
3851       * Contains the answers to this lesson_page once loaded
3852       * @var null|array
3853       */
3854      protected $answers = null;
3855      /**
3856       * This sets the type of the page, can be one of the constants defined below
3857       * @var int
3858       */
3859      protected $type = 0;
3860  
3861      /**
3862       * Constants used to identify the type of the page
3863       */
3864      const TYPE_QUESTION = 0;
3865      const TYPE_STRUCTURE = 1;
3866  
3867      /**
3868       * Constant used as a delimiter when parsing multianswer questions
3869       */
3870      const MULTIANSWER_DELIMITER = '@^#|';
3871  
3872      /**
3873       * This method should return the integer used to identify the page type within
3874       * the database and throughout code. This maps back to the defines used in 1.x
3875       * @abstract
3876       * @return int
3877       */
3878      abstract protected function get_typeid();
3879      /**
3880       * This method should return the string that describes the pagetype
3881       * @abstract
3882       * @return string
3883       */
3884      abstract protected function get_typestring();
3885  
3886      /**
3887       * This method gets called to display the page to the user taking the lesson
3888       * @abstract
3889       * @param object $renderer
3890       * @param object $attempt
3891       * @return string
3892       */
3893      abstract public function display($renderer, $attempt);
3894  
3895      /**
3896       * Creates a new lesson_page within the database and returns the correct pagetype
3897       * object to use to interact with the new lesson
3898       *
3899       * @final
3900       * @static
3901       * @param object $properties
3902       * @param lesson $lesson
3903       * @return lesson_page Specialised object that extends lesson_page
3904       */
3905      final public static function create($properties, lesson $lesson, $context, $maxbytes) {
3906          global $DB;
3907          $newpage = new stdClass;
3908          $newpage->title = $properties->title;
3909          $newpage->contents = $properties->contents_editor['text'];
3910          $newpage->contentsformat = $properties->contents_editor['format'];
3911          $newpage->lessonid = $lesson->id;
3912          $newpage->timecreated = time();
3913          $newpage->qtype = $properties->qtype;
3914          $newpage->qoption = (isset($properties->qoption))?1:0;
3915          $newpage->layout = (isset($properties->layout))?1:0;
3916          $newpage->display = (isset($properties->display))?1:0;
3917          $newpage->prevpageid = 0; // this is a first page
3918          $newpage->nextpageid = 0; // this is the only page
3919  
3920          if ($properties->pageid) {
3921              $prevpage = $DB->get_record("lesson_pages", array("id" => $properties->pageid), 'id, nextpageid');
3922              if (!$prevpage) {
3923                  throw new \moodle_exception('cannotfindpages', 'lesson');
3924              }
3925              $newpage->prevpageid = $prevpage->id;
3926              $newpage->nextpageid = $prevpage->nextpageid;
3927          } else {
3928              $nextpage = $DB->get_record('lesson_pages', array('lessonid'=>$lesson->id, 'prevpageid'=>0), 'id');
3929              if ($nextpage) {
3930                  // This is the first page, there are existing pages put this at the start
3931                  $newpage->nextpageid = $nextpage->id;
3932              }
3933          }
3934  
3935          $newpage->id = $DB->insert_record("lesson_pages", $newpage);
3936  
3937          $editor = new stdClass;
3938          $editor->id = $newpage->id;
3939          $editor->contents_editor = $properties->contents_editor;
3940          $editor = file_postupdate_standard_editor($editor, 'contents', array('noclean'=>true, 'maxfiles'=>EDITOR_UNLIMITED_FILES, 'maxbytes'=>$maxbytes), $context, 'mod_lesson', 'page_contents', $editor->id);
3941          $DB->update_record("lesson_pages", $editor);
3942  
3943          if ($newpage->prevpageid > 0) {
3944              $DB->set_field("lesson_pages", "nextpageid", $newpage->id, array("id" => $newpage->prevpageid));
3945          }
3946          if ($newpage->nextpageid > 0) {
3947              $DB->set_field("lesson_pages", "prevpageid", $newpage->id, array("id" => $newpage->nextpageid));
3948          }
3949  
3950          $page = lesson_page::load($newpage, $lesson);
3951          $page->create_answers($properties);
3952  
3953          // Trigger an event: page created.
3954          $eventparams = array(
3955              'context' => $context,
3956              'objectid' => $newpage->id,
3957              'other' => array(
3958                  'pagetype' => $page->get_typestring()
3959                  )
3960              );
3961          $event = \mod_lesson\event\page_created::create($eventparams);
3962          $snapshot = clone($newpage);
3963          $snapshot->timemodified = 0;
3964          $event->add_record_snapshot('lesson_pages', $snapshot);
3965          $event->trigger();
3966  
3967          $lesson->add_message(get_string('insertedpage', 'lesson').': '.format_string($newpage->title, true), 'notifysuccess');
3968  
3969          return $page;
3970      }
3971  
3972      /**
3973       * This method loads a page object from the database and returns it as a
3974       * specialised object that extends lesson_page
3975       *
3976       * @final
3977       * @static
3978       * @param int $id
3979       * @param lesson $lesson
3980       * @return lesson_page Specialised lesson_page object
3981       */
3982      final public static function load($id, lesson $lesson) {
3983          global $DB;
3984  
3985          if (is_object($id) && !empty($id->qtype)) {
3986              $page = $id;
3987          } else {
3988              $page = $DB->get_record("lesson_pages", array("id" => $id));
3989              if (!$page) {
3990                  throw new \moodle_exception('cannotfindpages', 'lesson');
3991              }
3992          }
3993          $manager = lesson_page_type_manager::get($lesson);
3994  
3995          $class = 'lesson_page_type_'.$manager->get_page_type_idstring($page->qtype);
3996          if (!class_exists($class)) {
3997              $class = 'lesson_page';
3998          }
3999  
4000          return new $class($page, $lesson);
4001      }
4002  
4003      /**
4004       * Deletes a lesson_page from the database as well as any associated records.
4005       * @final
4006       * @return bool
4007       */
4008      final public function delete() {
4009          global $DB;
4010  
4011          $cm = get_coursemodule_from_instance('lesson', $this->lesson->id, $this->lesson->course);
4012          $context = context_module::instance($cm->id);
4013  
4014          // Delete files associated with attempts.
4015          $fs = get_file_storage();
4016          if ($attempts = $DB->get_records('lesson_attempts', array("pageid" => $this->properties->id))) {
4017              foreach ($attempts as $attempt) {
4018                  $fs->delete_area_files($context->id, 'mod_lesson', 'essay_responses', $attempt->id);
4019                  $fs->delete_area_files($context->id, 'mod_lesson', 'essay_answers', $attempt->id);
4020              }
4021          }
4022  
4023          // Then delete all the associated records...
4024          $DB->delete_records("lesson_attempts", array("pageid" => $this->properties->id));
4025  
4026          $DB->delete_records("lesson_branch", array("pageid" => $this->properties->id));
4027  
4028          // Delete files related to answers and responses.
4029          if ($answers = $DB->get_records("lesson_answers", array("pageid" => $this->properties->id))) {
4030              foreach ($answers as $answer) {
4031                  $fs->delete_area_files($context->id, 'mod_lesson', 'page_answers', $answer->id);
4032                  $fs->delete_area_files($context->id, 'mod_lesson', 'page_responses', $answer->id);
4033              }
4034          }
4035  
4036          // ...now delete the answers...
4037          $DB->delete_records("lesson_answers", array("pageid" => $this->properties->id));
4038          // ..and the page itself
4039          $DB->delete_records("lesson_pages", array("id" => $this->properties->id));
4040  
4041          // Trigger an event: page deleted.
4042          $eventparams = array(
4043              'context' => $context,
4044              'objectid' => $this->properties->id,
4045              'other' => array(
4046                  'pagetype' => $this->get_typestring()
4047                  )
4048              );
4049          $event = \mod_lesson\event\page_deleted::create($eventparams);
4050          $event->add_record_snapshot('lesson_pages', $this->properties);
4051          $event->trigger();
4052  
4053          // Delete files associated with this page.
4054          $fs->delete_area_files($context->id, 'mod_lesson', 'page_contents', $this->properties->id);
4055  
4056          // repair the hole in the linkage
4057          if (!$this->properties->prevpageid && !$this->properties->nextpageid) {
4058              //This is the only page, no repair needed
4059          } elseif (!$this->properties->prevpageid) {
4060              // this is the first page...
4061              $page = $this->lesson->load_page($this->properties->nextpageid);
4062              $page->move(null, 0);
4063          } elseif (!$this->properties->nextpageid) {
4064              // this is the last page...
4065              $page = $this->lesson->load_page($this->properties->prevpageid);
4066              $page->move(0);
4067          } else {
4068              // page is in the middle...
4069              $prevpage = $this->lesson->load_page($this->properties->prevpageid);
4070              $nextpage = $this->lesson->load_page($this->properties->nextpageid);
4071  
4072              $prevpage->move($nextpage->id);
4073              $nextpage->move(null, $prevpage->id);
4074          }
4075          return true;
4076      }
4077  
4078      /**
4079       * Moves a page by updating its nextpageid and prevpageid values within
4080       * the database
4081       *
4082       * @final
4083       * @param int $nextpageid
4084       * @param int $prevpageid
4085       */
4086      final public function move($nextpageid=null, $prevpageid=null) {
4087          global $DB;
4088          if ($nextpageid === null) {
4089              $nextpageid = $this->properties->nextpageid;
4090          }
4091          if ($prevpageid === null) {
4092              $prevpageid = $this->properties->prevpageid;
4093          }
4094          $obj = new stdClass;
4095          $obj->id = $this->properties->id;
4096          $obj->prevpageid = $prevpageid;
4097          $obj->nextpageid = $nextpageid;
4098          $DB->update_record('lesson_pages', $obj);
4099      }
4100  
4101      /**
4102       * Returns the answers that are associated with this page in the database
4103       *
4104       * @final
4105       * @return array
4106       */
4107      final public function get_answers() {
4108          global $DB;
4109          if ($this->answers === null) {
4110              $this->answers = array();
4111              $answers = $DB->get_records('lesson_answers', array('pageid'=>$this->properties->id, 'lessonid'=>$this->lesson->id), 'id');
4112              if (!$answers) {
4113                  // It is possible that a lesson upgraded from Moodle 1.9 still
4114                  // contains questions without any answers [MDL-25632].
4115                  // debugging(get_string('cannotfindanswer', 'lesson'));
4116                  return array();
4117              }
4118              foreach ($answers as $answer) {
4119                  $this->answers[count($this->answers)] = new lesson_page_answer($answer);
4120              }
4121          }
4122          return $this->answers;
4123      }
4124  
4125      /**
4126       * Returns the lesson this page is associated with
4127       * @final
4128       * @return lesson
4129       */
4130      final protected function get_lesson() {
4131          return $this->lesson;
4132      }
4133  
4134      /**
4135       * Returns the type of page this is. Not to be confused with page type
4136       * @final
4137       * @return int
4138       */
4139      final protected function get_type() {
4140          return $this->type;
4141      }
4142  
4143      /**
4144       * Records an attempt at this page
4145       *
4146       * @final
4147       * @global moodle_database $DB
4148       * @param stdClass $context
4149       * @return stdClass Returns the result of the attempt
4150       */
4151      final public function record_attempt($context) {
4152          global $DB, $USER, $OUTPUT, $PAGE;
4153  
4154          /**
4155           * This should be overridden by each page type to actually check the response
4156           * against what ever custom criteria they have defined
4157           */
4158          $result = $this->check_answer();
4159  
4160          // Processes inmediate jumps.
4161          if ($result->inmediatejump) {
4162              return $result;
4163          }
4164  
4165          $result->attemptsremaining  = 0;
4166          $result->maxattemptsreached = false;
4167  
4168          if ($result->noanswer) {
4169              $result->newpageid = $this->properties->id; // display same page again
4170              $result->feedback  = get_string('noanswer', 'lesson');
4171          } else {
4172              if (!has_capability('mod/lesson:manage', $context)) {
4173                  $nretakes = $DB->count_records("lesson_grades", array("lessonid"=>$this->lesson->id, "userid"=>$USER->id));
4174  
4175                  // Get the number of attempts that have been made on this question for this student and retake,
4176                  $nattempts = $DB->count_records('lesson_attempts', array('lessonid' => $this->lesson->id,
4177                      'userid' => $USER->id, 'pageid' => $this->properties->id, 'retry' => $nretakes));
4178  
4179                  // Check if they have reached (or exceeded) the maximum number of attempts allowed.
4180                  if (!empty($this->lesson->maxattempts) && $nattempts >= $this->lesson->maxattempts) {
4181                      $result->maxattemptsreached = true;
4182                      $result->feedback = get_string('maximumnumberofattemptsreached', 'lesson');
4183                      $result->newpageid = $this->lesson->get_next_page($this->properties->nextpageid);
4184                      return $result;
4185                  }
4186  
4187                  // record student's attempt
4188                  $attempt = new stdClass;
4189                  $attempt->lessonid = $this->lesson->id;
4190                  $attempt->pageid = $this->properties->id;
4191                  $attempt->userid = $USER->id;
4192                  $attempt->answerid = $result->answerid;
4193                  $attempt->retry = $nretakes;
4194                  $attempt->correct = $result->correctanswer;
4195                  if($result->userresponse !== null) {
4196                      $attempt->useranswer = $result->userresponse;
4197                  }
4198  
4199                  $attempt->timeseen = time();
4200                  // if allow modattempts, then update the old attempt record, otherwise, insert new answer record
4201                  $userisreviewing = false;
4202                  if (isset($USER->modattempts[$this->lesson->id])) {
4203                      $attempt->retry = $nretakes - 1; // they are going through on review, $nretakes will be too high
4204                      $userisreviewing = true;
4205                  }
4206  
4207                  // Only insert a record if we are not reviewing the lesson.
4208                  if (!$userisreviewing) {
4209                      if ($this->lesson->retake || (!$this->lesson->retake && $nretakes == 0)) {
4210                          $attempt->id = $DB->insert_record("lesson_attempts", $attempt);
4211  
4212                          list($updatedattempt, $updatedresult) = $this->on_after_write_attempt($attempt, $result);
4213                          if ($updatedattempt) {
4214                              $attempt = $updatedattempt;
4215                              $result = $updatedresult;
4216                              $DB->update_record("lesson_attempts", $attempt);
4217                          }
4218  
4219                          // Trigger an event: question answered.
4220                          $eventparams = array(
4221                              'context' => context_module::instance($PAGE->cm->id),
4222                              'objectid' => $this->properties->id,
4223                              'other' => array(
4224                                  'pagetype' => $this->get_typestring()
4225                                  )
4226                              );
4227                          $event = \mod_lesson\event\question_answered::create($eventparams);
4228                          $event->add_record_snapshot('lesson_attempts', $attempt);
4229                          $event->trigger();
4230  
4231                          // Increase the number of attempts made.
4232                          $nattempts++;
4233                      }
4234                  } else {
4235                      // When reviewing the lesson, the existing attemptid is also needed for the filearea options.
4236                      $params = [
4237                          'lessonid' => $attempt->lessonid,
4238                          'pageid' => $attempt->pageid,
4239                          'userid' => $attempt->userid,
4240                          'answerid' => $attempt->answerid,
4241                          'retry' => $attempt->retry
4242                      ];
4243                      $attempt->id = $DB->get_field('lesson_attempts', 'id', $params);
4244                  }
4245                  // "number of attempts remaining" message if $this->lesson->maxattempts > 1
4246                  // displaying of message(s) is at the end of page for more ergonomic display
4247                  // If we are showing the number of remaining attempts, we need to show it regardless of what the next
4248                  // jump to page is.
4249                  if (!$result->correctanswer) {
4250                      // Retrieve the number of attempts left counter for displaying at bottom of feedback page.
4251                      if ($result->newpageid == 0 && !empty($this->lesson->maxattempts) && $nattempts >= $this->lesson->maxattempts) {
4252                          if ($this->lesson->maxattempts > 1) { // don't bother with message if only one attempt
4253                              $result->maxattemptsreached = true;
4254                          }
4255                          $result->newpageid = LESSON_NEXTPAGE;
4256                      } else if ($this->lesson->maxattempts > 1) { // don't bother with message if only one attempt
4257                          $result->attemptsremaining = $this->lesson->maxattempts - $nattempts;
4258                          if ($result->attemptsremaining == 0) {
4259                              $result->maxattemptsreached = true;
4260                          }
4261                      }
4262                  }
4263              }
4264  
4265              // Determine default feedback if necessary
4266              if (empty($result->response)) {
4267                  if (!$this->lesson->feedback && !$result->noanswer && !($this->lesson->review & !$result->correctanswer && !$result->isessayquestion)) {
4268                      // These conditions have been met:
4269                      //  1. The lesson manager has not supplied feedback to the student
4270                      //  2. Not displaying default feedback
4271                      //  3. The user did provide an answer
4272                      //  4. We are not reviewing with an incorrect answer (and not reviewing an essay question)
4273  
4274                      $result->nodefaultresponse = true;  // This will cause a redirect below
4275                  } else if ($result->isessayquestion) {
4276                      $result->response = get_string('defaultessayresponse', 'lesson');
4277                  } else if ($result->correctanswer) {
4278                      $result->response = get_string('thatsthecorrectanswer', 'lesson');
4279                  } else {
4280                      $result->response = get_string('thatsthewronganswer', 'lesson');
4281                  }
4282              }
4283  
4284              if ($result->response) {
4285                  if ($this->lesson->review && !$result->correctanswer && !$result->isessayquestion) {
4286                      $nretakes = $DB->count_records("lesson_grades", array("lessonid"=>$this->lesson->id, "userid"=>$USER->id));
4287                      $qattempts = $DB->count_records("lesson_attempts", array("userid"=>$USER->id, "retry"=>$nretakes, "pageid"=>$this->properties->id));
4288                      if ($qattempts == 1) {
4289                          $result->feedback = $OUTPUT->box(get_string("firstwrong", "lesson"), 'feedback');
4290                      } else {
4291                          if (!$result->maxattemptsreached) {
4292                              $result->feedback = $OUTPUT->box(get_string("secondpluswrong", "lesson"), 'feedback');
4293                          } else {
4294                              $result->feedback = $OUTPUT->box(get_string("finalwrong", "lesson"), 'feedback');
4295                          }
4296                      }
4297                  } else {
4298                      $result->feedback = '';
4299                  }
4300                  $class = 'response';
4301                  if ($result->correctanswer) {
4302                      $class .= ' correct'; // CSS over-ride this if they exist (!important).
4303                  } else if (!$result->isessayquestion) {
4304                      $class .= ' incorrect'; // CSS over-ride this if they exist (!important).
4305                  }
4306                  $options = new stdClass;
4307                  $options->noclean = true;
4308                  $options->para = true;
4309                  $options->overflowdiv = true;
4310                  $options->context = $context;
4311                  $options->attemptid = isset($attempt) ? $attempt->id : null;
4312  
4313                  $result->feedback .= $OUTPUT->box(format_text($this->get_contents(), $this->properties->contentsformat, $options),
4314                          'generalbox boxaligncenter py-3');
4315                  $result->feedback .= '<div class="correctanswer generalbox"><em>'
4316                          . get_string("youranswer", "lesson").'</em> : <div class="studentanswer mt-2 mb-2">';
4317  
4318                  // Create a table containing the answers and responses.
4319                  $table = new html_table();
4320                  // Multianswer allowed.
4321                  if ($this->properties->qoption) {
4322                      $studentanswerarray = explode(self::MULTIANSWER_DELIMITER, $result->studentanswer);
4323                      $responsearr = explode(self::MULTIANSWER_DELIMITER, $result->response);
4324                      $studentanswerresponse = array_combine($studentanswerarray, $responsearr);
4325  
4326                      foreach ($studentanswerresponse as $answer => $response) {
4327                          // Add a table row containing the answer.
4328                          $studentanswer = $this->format_answer($answer, $context, $result->studentanswerformat, $options);
4329                          $table->data[] = array($studentanswer);
4330                          // If the response exists, add a table row containing the response. If not, add en empty row.
4331                          if (!empty(trim($response))) {
4332                              $studentresponse = isset($result->responseformat) ?
4333                                  $this->format_response($response, $context, $result->responseformat, $options) : $response;
4334                              $studentresponsecontent = html_writer::div('<em>' . get_string("response", "lesson") .
4335                                  '</em>: <br/>' . $studentresponse, $class);
4336                              $table->data[] = array($studentresponsecontent);
4337                          } else {
4338                              $table->data[] = array('');
4339                          }
4340                      }
4341                  } else {
4342                      // Add a table row containing the answer.
4343                      $studentanswer = $this->format_answer($result->studentanswer, $context, $result->studentanswerformat, $options);
4344                      $table->data[] = array($studentanswer);
4345                      // If the response exists, add a table row containing the response. If not, add en empty row.
4346                      if (!empty(trim($result->response))) {
4347                          $studentresponse = isset($result->responseformat) ?
4348                              $this->format_response($result->response, $context, $result->responseformat,
4349                                  $result->answerid, $options) : $result->response;
4350                          $studentresponsecontent = html_writer::div('<em>' . get_string("response", "lesson") .
4351                              '</em>: <br/>' . $studentresponse, $class);
4352                          $table->data[] = array($studentresponsecontent);
4353                      } else {
4354                          $table->data[] = array('');
4355                      }
4356                  }
4357  
4358                  $result->feedback .= html_writer::table($table).'</div></div>';
4359              }
4360          }
4361          return $result;
4362      }
4363  
4364      /**
4365       * Formats the answer. Override for custom formatting.
4366       *
4367       * @param string $answer
4368       * @param context $context
4369       * @param int $answerformat
4370       * @return string Returns formatted string
4371       */
4372      public function format_answer($answer, $context, $answerformat, $options = []) {
4373  
4374          if (is_object($options)) {
4375              $options = (array) $options;
4376          }
4377  
4378          if (empty($options['context'])) {
4379              $options['context'] = $context;
4380          }
4381  
4382          if (empty($options['para'])) {
4383              $options['para'] = true;
4384          }
4385  
4386          return format_text($answer, $answerformat, $options);
4387      }
4388  
4389      /**
4390       * Formats the response
4391       *
4392       * @param string $response
4393       * @param context $context
4394       * @param int $responseformat
4395       * @param int $answerid
4396       * @param stdClass $options
4397       * @return string Returns formatted string
4398       */
4399      private function format_response($response, $context, $responseformat, $answerid, $options) {
4400  
4401          $convertstudentresponse = file_rewrite_pluginfile_urls($response, 'pluginfile.php',
4402              $context->id, 'mod_lesson', 'page_responses', $answerid);
4403  
4404          return format_text($convertstudentresponse, $responseformat, $options);
4405      }
4406  
4407      /**
4408       * Returns the string for a jump name
4409       *
4410       * @final
4411       * @param int $jumpto Jump code or page ID
4412       * @return string
4413       **/
4414      final protected function get_jump_name($jumpto) {
4415          global $DB;
4416          static $jumpnames = array();
4417  
4418          if (!array_key_exists($jumpto, $jumpnames)) {
4419              if ($jumpto == LESSON_THISPAGE) {
4420                  $jumptitle = get_string('thispage', 'lesson');
4421              } elseif ($jumpto == LESSON_NEXTPAGE) {
4422                  $jumptitle = get_string('nextpage', 'lesson');
4423              } elseif ($jumpto == LESSON_EOL) {
4424                  $jumptitle = get_string('endoflesson', 'lesson');
4425              } elseif ($jumpto == LESSON_UNSEENBRANCHPAGE) {
4426                  $jumptitle = get_string('unseenpageinbranch', 'lesson');
4427              } elseif ($jumpto == LESSON_PREVIOUSPAGE) {
4428                  $jumptitle = get_string('previouspage', 'lesson');
4429              } elseif ($jumpto == LESSON_RANDOMPAGE) {
4430                  $jumptitle = get_string('randompageinbranch', 'lesson');
4431              } elseif ($jumpto == LESSON_RANDOMBRANCH) {
4432                  $jumptitle = get_string('randombranch', 'lesson');
4433              } elseif ($jumpto == LESSON_CLUSTERJUMP) {
4434                  $jumptitle = get_string('clusterjump', 'lesson');
4435              } else {
4436                  if (!$jumptitle = $DB->get_field('lesson_pages', 'title', array('id' => $jumpto))) {
4437                      $jumptitle = '<strong>'.get_string('notdefined', 'lesson').'</strong>';
4438                  }
4439              }
4440              $jumpnames[$jumpto] = format_string($jumptitle,true);
4441          }
4442  
4443          return $jumpnames[$jumpto];
4444      }
4445  
4446      /**
4447       * Constructor method
4448       * @param object $properties
4449       * @param lesson $lesson
4450       */
4451      public function __construct($properties, lesson $lesson) {
4452          parent::__construct($properties);
4453          $this->lesson = $lesson;
4454      }
4455  
4456      /**
4457       * Returns the score for the attempt
4458       * This may be overridden by page types that require manual grading
4459       * @param array $answers
4460       * @param object $attempt
4461       * @return int
4462       */
4463      public function earned_score($answers, $attempt) {
4464          return $answers[$attempt->answerid]->score;
4465      }
4466  
4467      /**
4468       * This is a callback method that can be override and gets called when ever a page
4469       * is viewed
4470       *
4471       * @param bool $canmanage True if the user has the manage cap
4472       * @param bool $redirect  Optional, default to true. Set to false to avoid redirection and return the page to redirect.
4473       * @return mixed
4474       */
4475      public function callback_on_view($canmanage, $redirect = true) {
4476          return true;
4477      }
4478  
4479      /**
4480       * save editor answers files and update answer record
4481       *
4482       * @param object $context
4483       * @param int $maxbytes
4484       * @param object $answer
4485       * @param object $answereditor
4486       * @param object $responseeditor
4487       */
4488      public function save_answers_files($context, $maxbytes, &$answer, $answereditor = '', $responseeditor = '') {
4489          global $DB;
4490          if (isset($answereditor['itemid'])) {
4491              $answer->answer = file_save_draft_area_files($answereditor['itemid'],
4492                      $context->id, 'mod_lesson', 'page_answers', $answer->id,
4493                      array('noclean' => true, 'maxfiles' => EDITOR_UNLIMITED_FILES, 'maxbytes' => $maxbytes),
4494                      $answer->answer, null);
4495              $DB->set_field('lesson_answers', 'answer', $answer->answer, array('id' => $answer->id));
4496          }
4497          if (isset($responseeditor['itemid'])) {
4498              $answer->response = file_save_draft_area_files($responseeditor['itemid'],
4499                      $context->id, 'mod_lesson', 'page_responses', $answer->id,
4500                      array('noclean' => true, 'maxfiles' => EDITOR_UNLIMITED_FILES, 'maxbytes' => $maxbytes),
4501                      $answer->response, null);
4502              $DB->set_field('lesson_answers', 'response', $answer->response, array('id' => $answer->id));
4503          }
4504      }
4505  
4506      /**
4507       * Rewrite urls in response and optionality answer of a question answer
4508       *
4509       * @param object $answer
4510       * @param bool $rewriteanswer must rewrite answer
4511       * @return object answer with rewritten urls
4512       */
4513      public static function rewrite_answers_urls($answer, $rewriteanswer = true) {
4514          global $PAGE;
4515  
4516          $context = context_module::instance($PAGE->cm->id);
4517          if ($rewriteanswer) {
4518              $answer->answer = file_rewrite_pluginfile_urls($answer->answer, 'pluginfile.php', $context->id,
4519                      'mod_lesson', 'page_answers', $answer->id);
4520          }
4521          $answer->response = file_rewrite_pluginfile_urls($answer->response, 'pluginfile.php', $context->id,
4522                  'mod_lesson', 'page_responses', $answer->id);
4523  
4524          return $answer;
4525      }
4526  
4527      /**
4528       * Updates a lesson page and its answers within the database
4529       *
4530       * @param object $properties
4531       * @return bool
4532       */
4533      public function update($properties, $context = null, $maxbytes = null) {
4534          global $DB, $PAGE;
4535          $answers  = $this->get_answers();
4536          $properties->id = $this->properties->id;
4537          $properties->lessonid = $this->lesson->id;
4538          if (empty($properties->qoption)) {
4539              $properties->qoption = '0';
4540          }
4541          if (empty($context)) {
4542              $context = $PAGE->context;
4543          }
4544          if ($maxbytes === null) {
4545              $maxbytes = get_user_max_upload_file_size($context);
4546          }
4547          $properties->timemodified = time();
4548          $properties = file_postupdate_standard_editor($properties, 'contents', array('noclean'=>true, 'maxfiles'=>EDITOR_UNLIMITED_FILES, 'maxbytes'=>$maxbytes), $context, 'mod_lesson', 'page_contents', $properties->id);
4549          $DB->update_record("lesson_pages", $properties);
4550  
4551          // Trigger an event: page updated.
4552          \mod_lesson\event\page_updated::create_from_lesson_page($this, $context)->trigger();
4553  
4554          if ($this->type == self::TYPE_STRUCTURE && $this->get_typeid() != LESSON_PAGE_BRANCHTABLE) {
4555              // These page types have only one answer to save the jump and score.
4556              if (count($answers) > 1) {
4557                  $answer = array_shift($answers);
4558                  foreach ($answers as $a) {
4559                      $DB->delete_records('lesson_answers', array('id' => $a->id));
4560                  }
4561              } else if (count($answers) == 1) {
4562                  $answer = array_shift($answers);
4563              } else {
4564                  $answer = new stdClass;
4565                  $answer->lessonid = $properties->lessonid;
4566                  $answer->pageid = $properties->id;
4567                  $answer->timecreated = time();
4568              }
4569  
4570              $answer->timemodified = time();
4571              if (isset($properties->jumpto[0])) {
4572                  $answer->jumpto = $properties->jumpto[0];
4573              }
4574              if (isset($properties->score[0])) {
4575                  $answer->score = $properties->score[0];
4576              }
4577              if (!empty($answer->id)) {
4578                  $DB->update_record("lesson_answers", $answer->properties());
4579              } else {
4580                  $DB->insert_record("lesson_answers", $answer);
4581              }
4582          } else {
4583              for ($i = 0; $i < count($properties->answer_editor); $i++) {
4584                  if (!array_key_exists($i, $this->answers)) {
4585                      $this->answers[$i] = new stdClass;
4586                      $this->answers[$i]->lessonid = $this->lesson->id;
4587                      $this->answers[$i]->pageid = $this->id;
4588                      $this->answers[$i]->timecreated = $this->timecreated;
4589                      $this->answers[$i]->answer = null;
4590                  }
4591  
4592                  if (isset($properties->answer_editor[$i])) {
4593                      if (is_array($properties->answer_editor[$i])) {
4594                          // Multichoice and true/false pages have an HTML editor.
4595                          $this->answers[$i]->answer = $properties->answer_editor[$i]['text'];
4596                          $this->answers[$i]->answerformat = $properties->answer_editor[$i]['format'];
4597                      } else {
4598                          // Branch tables, shortanswer and mumerical pages have only a text field.
4599                          $this->answers[$i]->answer = $properties->answer_editor[$i];
4600                          $this->answers[$i]->answerformat = FORMAT_MOODLE;
4601                      }
4602                  } else {
4603                      // If there is no data posted which means we want to reset the stored values.
4604                      $this->answers[$i]->answer = null;
4605                  }
4606  
4607                  if (!empty($properties->response_editor[$i]) && is_array($properties->response_editor[$i])) {
4608                      $this->answers[$i]->response = $properties->response_editor[$i]['text'];
4609                      $this->answers[$i]->responseformat = $properties->response_editor[$i]['format'];
4610                  }
4611  
4612                  if ($this->answers[$i]->answer !== null && $this->answers[$i]->answer !== '') {
4613                      if (isset($properties->jumpto[$i])) {
4614                          $this->answers[$i]->jumpto = $properties->jumpto[$i];
4615                      }
4616                      if ($this->lesson->custom && isset($properties->score[$i])) {
4617                          $this->answers[$i]->score = $properties->score[$i];
4618                      }
4619                      if (!isset($this->answers[$i]->id)) {
4620                          $this->answers[$i]->id = $DB->insert_record("lesson_answers", $this->answers[$i]);
4621                      } else {
4622                          $DB->update_record("lesson_answers", $this->answers[$i]->properties());
4623                      }
4624  
4625                      // Save files in answers and responses.
4626                      if (isset($properties->response_editor[$i])) {
4627                          $this->save_answers_files($context, $maxbytes, $this->answers[$i],
4628                                  $properties->answer_editor[$i], $properties->response_editor[$i]);
4629                      } else {
4630                          $this->save_answers_files($context, $maxbytes, $this->answers[$i],
4631                                  $properties->answer_editor[$i]);
4632                      }
4633  
4634                  } else if (isset($this->answers[$i]->id)) {
4635                      $DB->delete_records('lesson_answers', array('id' => $this->answers[$i]->id));
4636                      unset($this->answers[$i]);
4637                  }
4638              }
4639          }
4640          return true;
4641      }
4642  
4643      /**
4644       * Can be set to true if the page requires a static link to create a new instance
4645       * instead of simply being included in the dropdown
4646       * @param int $previd
4647       * @return bool
4648       */
4649      public function add_page_link($previd) {
4650          return false;
4651      }
4652  
4653      /**
4654       * Returns true if a page has been viewed before
4655       *
4656       * @param array|int $param Either an array of pages that have been seen or the
4657       *                   number of retakes a user has had
4658       * @return bool
4659       */
4660      public function is_unseen($param) {
4661          global $USER, $DB;
4662          if (is_array($param)) {
4663              $seenpages = $param;
4664              return (!array_key_exists($this->properties->id, $seenpages));
4665          } else {
4666              $nretakes = $param;
4667              if (!$DB->count_records("lesson_attempts", array("pageid"=>$this->properties->id, "userid"=>$USER->id, "retry"=>$nretakes))) {
4668                  return true;
4669              }
4670          }
4671          return false;
4672      }
4673  
4674      /**
4675       * Checks to see if a page has been answered previously
4676       * @param int $nretakes
4677       * @return bool
4678       */
4679      public function is_unanswered($nretakes) {
4680          global $DB, $USER;
4681          if (!$DB->count_records("lesson_attempts", array('pageid'=>$this->properties->id, 'userid'=>$USER->id, 'correct'=>1, 'retry'=>$nretakes))) {
4682              return true;
4683          }
4684          return false;
4685      }
4686  
4687      /**
4688       * Creates answers within the database for this lesson_page. Usually only ever
4689       * called when creating a new page instance
4690       * @param object $properties
4691       * @return array
4692       */
4693      public function create_answers($properties) {
4694          global $DB, $PAGE;
4695          // now add the answers
4696          $newanswer = new stdClass;
4697          $newanswer->lessonid = $this->lesson->id;
4698          $newanswer->pageid = $this->properties->id;
4699          $newanswer->timecreated = $this->properties->timecreated;
4700  
4701          $cm = get_coursemodule_from_instance('lesson', $this->lesson->id, $this->lesson->course);
4702          $context = context_module::instance($cm->id);
4703  
4704          $answers = array();
4705  
4706          for ($i = 0; $i < ($this->lesson->maxanswers + 1); $i++) {
4707              $answer = clone($newanswer);
4708  
4709              if (isset($properties->answer_editor[$i])) {
4710                  if (is_array($properties->answer_editor[$i])) {
4711                      // Multichoice and true/false pages have an HTML editor.
4712                      $answer->answer = $properties->answer_editor[$i]['text'];
4713                      $answer->answerformat = $properties->answer_editor[$i]['format'];
4714                  } else {
4715                      // Branch tables, shortanswer and mumerical pages have only a text field.
4716                      $answer->answer = $properties->answer_editor[$i];
4717                      $answer->answerformat = FORMAT_MOODLE;
4718                  }
4719              }
4720              if (!empty($properties->response_editor[$i]) && is_array($properties->response_editor[$i])) {
4721                  $answer->response = $properties->response_editor[$i]['text'];
4722                  $answer->responseformat = $properties->response_editor[$i]['format'];
4723              }
4724  
4725              if (isset($answer->answer) && $answer->answer != '') {
4726                  if (isset($properties->jumpto[$i])) {
4727                      $answer->jumpto = $properties->jumpto[$i];
4728                  }
4729                  if ($this->lesson->custom && isset($properties->score[$i])) {
4730                      $answer->score = $properties->score[$i];
4731                  }
4732                  $answer->id = $DB->insert_record("lesson_answers", $answer);
4733                  if (isset($properties->response_editor[$i])) {
4734                      $this->save_answers_files($context, $PAGE->course->maxbytes, $answer,
4735                              $properties->answer_editor[$i], $properties->response_editor[$i]);
4736                  } else {
4737                      $this->save_answers_files($context, $PAGE->course->maxbytes, $answer,
4738                              $properties->answer_editor[$i]);
4739                  }
4740                  $answers[$answer->id] = new lesson_page_answer($answer);
4741              }
4742          }
4743  
4744          $this->answers = $answers;
4745          return $answers;
4746      }
4747  
4748      /**
4749       * This method MUST be overridden by all question page types, or page types that
4750       * wish to score a page.
4751       *
4752       * The structure of result should always be the same so it is a good idea when
4753       * overriding this method on a page type to call
4754       * <code>
4755       * $result = parent::check_answer();
4756       * </code>
4757       * before modifying it as required.
4758       *
4759       * @return stdClass
4760       */
4761      public function check_answer() {
4762          $result = new stdClass;
4763          $result->answerid        = 0;
4764          $result->noanswer        = false;
4765          $result->correctanswer   = false;
4766          $result->isessayquestion = false;   // use this to turn off review button on essay questions
4767          $result->response        = '';
4768          $result->newpageid       = 0;       // stay on the page
4769          $result->studentanswer   = '';      // use this to store student's answer(s) in order to display it on feedback page
4770          $result->studentanswerformat = FORMAT_MOODLE;
4771          $result->userresponse    = null;
4772          $result->feedback        = '';
4773          // Store data that was POSTd by a form. This is currently used to perform any logic after the 1st write to the db
4774          // of the attempt.
4775          $result->postdata        = false;
4776          $result->nodefaultresponse  = false; // Flag for redirecting when default feedback is turned off
4777          $result->inmediatejump = false; // Flag to detect when we should do a jump from the page without further processing.
4778          return $result;
4779      }
4780  
4781      /**
4782       * Do any post persistence processing logic of an attempt. E.g. in cases where we need update file urls in an editor
4783       * and we need to have the id of the stored attempt. Should be overridden in each individual child
4784       * pagetype on a as required basis
4785       *
4786       * @param object $attempt The attempt corresponding to the db record
4787       * @param object $result The result from the 'check_answer' method
4788       * @return array False if nothing to be modified, updated $attempt and $result if update required.
4789       */
4790      public function on_after_write_attempt($attempt, $result) {
4791          return [false, false];
4792      }
4793  
4794      /**
4795       * True if the page uses a custom option
4796       *
4797       * Should be override and set to true if the page uses a custom option.
4798       *
4799       * @return bool
4800       */
4801      public function has_option() {
4802          return false;
4803      }
4804  
4805      /**
4806       * Returns the maximum number of answers for this page given the maximum number
4807       * of answers permitted by the lesson.
4808       *
4809       * @param int $default
4810       * @return int
4811       */
4812      public function max_answers($default) {
4813          return $default;
4814      }
4815  
4816      /**
4817       * Returns the properties of this lesson page as an object
4818       * @return stdClass;
4819       */
4820      public function properties() {
4821          $properties = clone($this->properties);
4822          if ($this->answers === null) {
4823              $this->get_answers();
4824          }
4825          if (count($this->answers)>0) {
4826              $count = 0;
4827              $qtype = $properties->qtype;
4828              foreach ($this->answers as $answer) {
4829                  $properties->{'answer_editor['.$count.']'} = array('text' => $answer->answer, 'format' => $answer->answerformat);
4830                  if ($qtype != LESSON_PAGE_MATCHING) {
4831                      $properties->{'response_editor['.$count.']'} = array('text' => $answer->response, 'format' => $answer->responseformat);
4832                  } else {
4833                      $properties->{'response_editor['.$count.']'} = $answer->response;
4834                  }
4835                  $properties->{'jumpto['.$count.']'} = $answer->jumpto;
4836                  $properties->{'score['.$count.']'} = $answer->score;
4837                  $count++;
4838              }
4839          }
4840          return $properties;
4841      }
4842  
4843      /**
4844       * Returns an array of options to display when choosing the jumpto for a page/answer
4845       * @static
4846       * @param int $pageid
4847       * @param lesson $lesson
4848       * @return array
4849       */
4850      public static function get_jumptooptions($pageid, lesson $lesson) {
4851          global $DB;
4852          $jump = array();
4853          $jump[0] = get_string("thispage", "lesson");
4854          $jump[LESSON_NEXTPAGE] = get_string("nextpage", "lesson");
4855          $jump[LESSON_PREVIOUSPAGE] = get_string("previouspage", "lesson");
4856          $jump[LESSON_EOL] = get_string("endoflesson", "lesson");
4857  
4858          if ($pageid == 0) {
4859              return $jump;
4860          }
4861  
4862          $pages = $lesson->load_all_pages();
4863          if ($pages[$pageid]->qtype == LESSON_PAGE_BRANCHTABLE || $lesson->is_sub_page_of_type($pageid, array(LESSON_PAGE_BRANCHTABLE), array(LESSON_PAGE_ENDOFBRANCH, LESSON_PAGE_CLUSTER))) {
4864              $jump[LESSON_UNSEENBRANCHPAGE] = get_string("unseenpageinbranch", "lesson");
4865              $jump[LESSON_RANDOMPAGE] = get_string("randompageinbranch", "lesson");
4866          }
4867          if($pages[$pageid]->qtype == LESSON_PAGE_CLUSTER || $lesson->is_sub_page_of_type($pageid, array(LESSON_PAGE_CLUSTER), array(LESSON_PAGE_ENDOFCLUSTER))) {
4868              $jump[LESSON_CLUSTERJUMP] = get_string("clusterjump", "lesson");
4869          }
4870          if (!optional_param('firstpage', 0, PARAM_INT)) {
4871              $apageid = $DB->get_field("lesson_pages", "id", array("lessonid" => $lesson->id, "prevpageid" => 0));
4872              while (true) {
4873                  if ($apageid) {
4874                      $title = $DB->get_field("lesson_pages", "title", array("id" => $apageid));
4875                      $jump[$apageid] = strip_tags(format_string($title,true));
4876                      $apageid = $DB->get_field("lesson_pages", "nextpageid", array("id" => $apageid));
4877                  } else {
4878                      // last page reached
4879                      break;
4880                  }
4881              }
4882          }
4883          return $jump;
4884      }
4885      /**
4886       * Returns the contents field for the page properly formatted and with plugin
4887       * file url's converted
4888       * @return string
4889       */
4890      public function get_contents() {
4891          global $PAGE;
4892          if (!empty($this->properties->contents)) {
4893              if (!isset($this->properties->contentsformat)) {
4894                  $this->properties->contentsformat = FORMAT_HTML;
4895              }
4896              $context = context_module::instance($PAGE->cm->id);
4897              $contents = file_rewrite_pluginfile_urls($this->properties->contents, 'pluginfile.php', $context->id, 'mod_lesson',
4898                                                       'page_contents', $this->properties->id);  // Must do this BEFORE format_text()!
4899              return format_text($contents, $this->properties->contentsformat,
4900                                 array('context' => $context, 'noclean' => true,
4901                                       'overflowdiv' => true));  // Page edit is marked with XSS, we want all content here.
4902          } else {
4903              return '';
4904          }
4905      }
4906  
4907      /**
4908       * Set to true if this page should display in the menu block
4909       * @return bool
4910       */
4911      protected function get_displayinmenublock() {
4912          return false;
4913      }
4914  
4915      /**
4916       * Get the string that describes the options of this page type
4917       * @return string
4918       */
4919      public function option_description_string() {
4920          return '';
4921      }
4922  
4923      /**
4924       * Updates a table with the answers for this page
4925       * @param html_table $table
4926       * @return html_table
4927       */
4928      public function display_answers(html_table $table) {
4929          $answers = $this->get_answers();
4930          $i = 1;
4931          foreach ($answers as $answer) {
4932              $cells = array();
4933              $cells[] = '<label>' . get_string('jump', 'lesson') . ' ' . $i . '</label>:';
4934              $cells[] = $this->get_jump_name($answer->jumpto);
4935              $table->data[] = new html_table_row($cells);
4936              if ($i === 1){
4937                  $table->data[count($table->data)-1]->cells[0]->style = 'width:20%;';
4938              }
4939              $i++;
4940          }
4941          return $table;
4942      }
4943  
4944      /**
4945       * Determines if this page should be grayed out on the management/report screens
4946       * @return int 0 or 1
4947       */
4948      protected function get_grayout() {
4949          return 0;
4950      }
4951  
4952      /**
4953       * Adds stats for this page to the &pagestats object. This should be defined
4954       * for all page types that grade
4955       * @param array $pagestats
4956       * @param int $tries
4957       * @return bool
4958       */
4959      public function stats(array &$pagestats, $tries) {
4960          return true;
4961      }
4962  
4963      /**
4964       * Formats the answers of this page for a report
4965       *
4966       * @param object $answerpage
4967       * @param object $answerdata
4968       * @param object $useranswer
4969       * @param array $pagestats
4970       * @param int $i Count of first level answers
4971       * @param int $n Count of second level answers
4972       * @return object The answer page for this
4973       */
4974      public function report_answers($answerpage, $answerdata, $useranswer, $pagestats, &$i, &$n) {
4975          $answers = $this->get_answers();
4976          $formattextdefoptions = new stdClass;
4977          $formattextdefoptions->para = false;  //I'll use it widely in this page
4978          foreach ($answers as $answer) {
4979              $data = get_string('jumpsto', 'lesson', $this->get_jump_name($answer->jumpto));
4980              $answerdata->answers[] = array($data, "");
4981              $answerpage->answerdata = $answerdata;
4982          }
4983          return $answerpage;
4984      }
4985  
4986      /**
4987       * Gets an array of the jumps used by the answers of this page
4988       *
4989       * @return array
4990       */
4991      public function get_jumps() {
4992          global $DB;
4993          $jumps = array();
4994          $params = array ("lessonid" => $this->lesson->id, "pageid" => $this->properties->id);
4995          if ($answers = $this->get_answers()) {
4996              foreach ($answers as $answer) {
4997                  $jumps[] = $this->get_jump_name($answer->jumpto);
4998              }
4999          } else {
5000              $jumps[] = $this->get_jump_name($this->properties->nextpageid);
5001          }
5002          return $jumps;
5003      }
5004      /**
5005       * Informs whether this page type require manual grading or not
5006       * @return bool
5007       */
5008      public function requires_manual_grading() {
5009          return false;
5010      }
5011  
5012      /**
5013       * A callback method that allows a page to override the next page a user will
5014       * see during when this page is being completed.
5015       * @return false|int
5016       */
5017      public function override_next_page() {
5018          return false;
5019      }
5020  
5021      /**
5022       * This method is used to determine if this page is a valid page
5023       *
5024       * @param array $validpages
5025       * @param array $pageviews
5026       * @return int The next page id to check
5027       */
5028      public function valid_page_and_view(&$validpages, &$pageviews) {
5029          $validpages[$this->properties->id] = 1;
5030          return $this->properties->nextpageid;
5031      }
5032  
5033      /**
5034       * Get files from the page area file.
5035       *
5036       * @param bool $includedirs whether or not include directories
5037       * @param int $updatedsince return files updated since this time
5038       * @return array list of stored_file objects
5039       * @since  Moodle 3.2
5040       */
5041      public function get_files($includedirs = true, $updatedsince = 0) {
5042          $fs = get_file_storage();
5043          return $fs->get_area_files($this->lesson->context->id, 'mod_lesson', 'page_contents', $this->properties->id,
5044                                      'itemid, filepath, filename', $includedirs, $updatedsince);
5045      }
5046  
5047      /**
5048       * Make updates to the form data if required.
5049       *
5050       * @since Moodle 3.7
5051       * @param stdClass $data The form data to update.
5052       * @return stdClass The updated fom data.
5053       */
5054      public function update_form_data(stdClass $data) : stdClass {
5055          return $data;
5056      }
5057  }
5058  
5059  
5060  
5061  /**
5062   * Class used to represent an answer to a page
5063   *
5064   * @property int $id The ID of this answer in the database
5065   * @property int $lessonid The ID of the lesson this answer belongs to
5066   * @property int $pageid The ID of the page this answer belongs to
5067   * @property int $jumpto Identifies where the user goes upon completing a page with this answer
5068   * @property int $grade The grade this answer is worth
5069   * @property int $score The score this answer will give
5070   * @property int $flags Used to store options for the answer
5071   * @property int $timecreated A timestamp of when the answer was created
5072   * @property int $timemodified A timestamp of when the answer was modified
5073   * @property string $answer The answer itself
5074   * @property string $response The response the user sees if selecting this answer
5075   *
5076   * @copyright  2009 Sam Hemelryk
5077   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
5078   */
5079  class lesson_page_answer extends lesson_base {
5080  
5081      /**
5082       * Loads an page answer from the DB
5083       *
5084       * @param int $id
5085       * @return lesson_page_answer
5086       */
5087      public static function load($id) {
5088          global $DB;
5089          $answer = $DB->get_record("lesson_answers", array("id" => $id));
5090          return new lesson_page_answer($answer);
5091      }
5092  
5093      /**
5094       * Given an object of properties and a page created answer(s) and saves them
5095       * in the database.
5096       *
5097       * @param stdClass $properties
5098       * @param lesson_page $page
5099       * @return array
5100       */
5101      public static function create($properties, lesson_page $page) {
5102          return $page->create_answers($properties);
5103      }
5104  
5105      /**
5106       * Get files from the answer area file.
5107       *
5108       * @param bool $includedirs whether or not include directories
5109       * @param int $updatedsince return files updated since this time
5110       * @return array list of stored_file objects
5111       * @since  Moodle 3.2
5112       */
5113      public function get_files($includedirs = true, $updatedsince = 0) {
5114  
5115          $lesson = lesson::load($this->properties->lessonid);
5116          $fs = get_file_storage();
5117          $answerfiles = $fs->get_area_files($lesson->context->id, 'mod_lesson', 'page_answers', $this->properties->id,
5118                                              'itemid, filepath, filename', $includedirs, $updatedsince);
5119          $responsefiles = $fs->get_area_files($lesson->context->id, 'mod_lesson', 'page_responses', $this->properties->id,
5120                                              'itemid, filepath, filename', $includedirs, $updatedsince);
5121          return array_merge($answerfiles, $responsefiles);
5122      }
5123  
5124  }
5125  
5126  /**
5127   * A management class for page types
5128   *
5129   * This class is responsible for managing the different pages. A manager object can
5130   * be retrieved by calling the following line of code:
5131   * <code>
5132   * $manager  = lesson_page_type_manager::get($lesson);
5133   * </code>
5134   * The first time the page type manager is retrieved the it includes all of the
5135   * different page types located in mod/lesson/pagetypes.
5136   *
5137   * @copyright  2009 Sam Hemelryk
5138   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
5139   */
5140  class lesson_page_type_manager {
5141  
5142      /**
5143       * An array of different page type classes
5144       * @var array
5145       */
5146      protected $types = array();
5147  
5148      /**
5149       * Retrieves the lesson page type manager object
5150       *
5151       * If the object hasn't yet been created it is created here.
5152       *
5153       * @staticvar lesson_page_type_manager $pagetypemanager
5154       * @param lesson $lesson
5155       * @return lesson_page_type_manager
5156       */
5157      public static function get(lesson $lesson) {
5158          static $pagetypemanager;
5159          if (!($pagetypemanager instanceof lesson_page_type_manager)) {
5160              $pagetypemanager = new lesson_page_type_manager();
5161              $pagetypemanager->load_lesson_types($lesson);
5162          }
5163          return $pagetypemanager;
5164      }
5165  
5166      /**
5167       * Finds and loads all lesson page types in mod/lesson/pagetypes
5168       *
5169       * @param lesson $lesson
5170       */
5171      public function load_lesson_types(lesson $lesson) {
5172          global $CFG;
5173          $basedir = $CFG->dirroot.'/mod/lesson/pagetypes/';
5174          $dir = dir($basedir);
5175          while (false !== ($entry = $dir->read())) {
5176              if (strpos($entry, '.')===0 || !preg_match('#^[a-zA-Z]+\.php#i', $entry)) {
5177                  continue;
5178              }
5179              require_once($basedir.$entry);
5180              $class = 'lesson_page_type_'.strtok($entry,'.');
5181              if (class_exists($class)) {
5182                  $pagetype = new $class(new stdClass, $lesson);
5183                  $this->types[$pagetype->typeid] = $pagetype;
5184              }
5185          }
5186  
5187      }
5188  
5189      /**
5190       * Returns an array of strings to describe the loaded page types
5191       *
5192       * @param int $type Can be used to return JUST the string for the requested type
5193       * @return array
5194       */
5195      public function get_page_type_strings($type=null, $special=true) {
5196          $types = array();
5197          foreach ($this->types as $pagetype) {
5198              if (($type===null || $pagetype->type===$type) && ($special===true || $pagetype->is_standard())) {
5199                  $types[$pagetype->typeid] = $pagetype->typestring;
5200              }
5201          }
5202          return $types;
5203      }
5204  
5205      /**
5206       * Returns the basic string used to identify a page type provided with an id
5207       *
5208       * This string can be used to instantiate or identify the page type class.
5209       * If the page type id is unknown then 'unknown' is returned
5210       *
5211       * @param int $id
5212       * @return string
5213       */
5214      public function get_page_type_idstring($id) {
5215          foreach ($this->types as $pagetype) {
5216              if ((int)$pagetype->typeid === (int)$id) {
5217                  return $pagetype->idstring;
5218              }
5219          }
5220          return 'unknown';
5221      }
5222  
5223      /**
5224       * Loads a page for the provided lesson given it's id
5225       *
5226       * This function loads a page from the lesson when given both the lesson it belongs
5227       * to as well as the page's id.
5228       * If the page doesn't exist an error is thrown
5229       *
5230       * @param int $pageid The id of the page to load
5231       * @param lesson $lesson The lesson the page belongs to
5232       * @return lesson_page A class that extends lesson_page
5233       */
5234      public function load_page($pageid, lesson $lesson) {
5235          global $DB;
5236          if (!($page =$DB->get_record('lesson_pages', array('id'=>$pageid, 'lessonid'=>$lesson->id)))) {
5237              throw new \moodle_exception('cannotfindpages', 'lesson');
5238          }
5239          $pagetype = get_class($this->types[$page->qtype]);
5240          $page = new $pagetype($page, $lesson);
5241          return $page;
5242      }
5243  
5244      /**
5245       * This function detects errors in the ordering between 2 pages and updates the page records.
5246       *
5247       * @param stdClass $page1 Either the first of 2 pages or null if the $page2 param is the first in the list.
5248       * @param stdClass $page1 Either the second of 2 pages or null if the $page1 param is the last in the list.
5249       */
5250      protected function check_page_order($page1, $page2) {
5251          global $DB;
5252          if (empty($page1)) {
5253              if ($page2->prevpageid != 0) {
5254                  debugging("***prevpageid of page " . $page2->id . " set to 0***");
5255                  $page2->prevpageid = 0;
5256                  $DB->set_field("lesson_pages", "prevpageid", 0, array("id" => $page2->id));
5257              }
5258          } else if (empty($page2)) {
5259              if ($page1->nextpageid != 0) {
5260                  debugging("***nextpageid of page " . $page1->id . " set to 0***");
5261                  $page1->nextpageid = 0;
5262                  $DB->set_field("lesson_pages", "nextpageid", 0, array("id" => $page1->id));
5263              }
5264          } else {
5265              if ($page1->nextpageid != $page2->id) {
5266                  debugging("***nextpageid of page " . $page1->id . " set to " . $page2->id . "***");
5267                  $page1->nextpageid = $page2->id;
5268                  $DB->set_field("lesson_pages", "nextpageid", $page2->id, array("id" => $page1->id));
5269              }
5270              if ($page2->prevpageid != $page1->id) {
5271                  debugging("***prevpageid of page " . $page2->id . " set to " . $page1->id . "***");
5272                  $page2->prevpageid = $page1->id;
5273                  $DB->set_field("lesson_pages", "prevpageid", $page1->id, array("id" => $page2->id));
5274              }
5275          }
5276      }
5277  
5278      /**
5279       * This function loads ALL pages that belong to the lesson.
5280       *
5281       * @param lesson $lesson
5282       * @return array An array of lesson_page_type_*
5283       */
5284      public function load_all_pages(lesson $lesson) {
5285          global $DB;
5286          if (!($pages =$DB->get_records('lesson_pages', array('lessonid'=>$lesson->id)))) {
5287              return array(); // Records returned empty.
5288          }
5289          foreach ($pages as $key=>$page) {
5290              $pagetype = get_class($this->types[$page->qtype]);
5291              $pages[$key] = new $pagetype($page, $lesson);
5292          }
5293  
5294          $orderedpages = array();
5295          $lastpageid = 0;
5296          $morepages = true;
5297          while ($morepages) {
5298              $morepages = false;
5299              foreach ($pages as $page) {
5300                  if ((int)$page->prevpageid === (int)$lastpageid) {
5301                      // Check for errors in page ordering and fix them on the fly.
5302                      $prevpage = null;
5303                      if ($lastpageid !== 0) {
5304                          $prevpage = $orderedpages[$lastpageid];
5305                      }
5306                      $this->check_page_order($prevpage, $page);
5307                      $morepages = true;
5308                      $orderedpages[$page->id] = $page;
5309                      unset($pages[$page->id]);
5310                      $lastpageid = $page->id;
5311                      if ((int)$page->nextpageid===0) {
5312                          break 2;
5313                      } else {
5314                          break 1;
5315                      }
5316                  }
5317              }
5318          }
5319  
5320          // Add remaining pages and fix the nextpageid links for each page.
5321          foreach ($pages as $page) {
5322              // Check for errors in page ordering and fix them on the fly.
5323              $prevpage = null;
5324              if ($lastpageid !== 0) {
5325                  $prevpage = $orderedpages[$lastpageid];
5326              }
5327              $this->check_page_order($prevpage, $page);
5328              $orderedpages[$page->id] = $page;
5329              unset($pages[$page->id]);
5330              $lastpageid = $page->id;
5331          }
5332  
5333          if ($lastpageid !== 0) {
5334              $this->check_page_order($orderedpages[$lastpageid], null);
5335          }
5336  
5337          return $orderedpages;
5338      }
5339  
5340      /**
5341       * Fetches an mform that can be used to create/edit an page
5342       *
5343       * @param int $type The id for the page type
5344       * @param array $arguments Any arguments to pass to the mform
5345       * @return lesson_add_page_form_base
5346       */
5347      public function get_page_form($type, $arguments) {
5348          $class = 'lesson_add_page_form_'.$this->get_page_type_idstring($type);
5349          if (!class_exists($class) || get_parent_class($class)!=='lesson_add_page_form_base') {
5350              debugging('Lesson page type unknown class requested '.$class, DEBUG_DEVELOPER);
5351              $class = 'lesson_add_page_form_selection';
5352          } else if ($class === 'lesson_add_page_form_unknown') {
5353              $class = 'lesson_add_page_form_selection';
5354          }
5355          return new $class(null, $arguments);
5356      }
5357  
5358      /**
5359       * Returns an array of links to use as add page links
5360       * @param int $previd The id of the previous page
5361       * @return array
5362       */
5363      public function get_add_page_type_links($previd) {
5364          global $OUTPUT;
5365  
5366          $links = array();
5367  
5368          foreach ($this->types as $key=>$type) {
5369              if ($link = $type->add_page_link($previd)) {
5370                  $links[$key] = $link;
5371              }
5372          }
5373  
5374          return $links;
5375      }
5376  }