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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Question behaviour where the student can submit questions one at a
  19   * time for immediate feedback.
  20   *
  21   * @package    qbehaviour
  22   * @subpackage interactive
  23   * @copyright  2009 The Open University
  24   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25   */
  26  
  27  
  28  defined('MOODLE_INTERNAL') || die();
  29  
  30  
  31  /**
  32   * Question behaviour for the interactive model.
  33   *
  34   * Each question has a submit button next to it which the student can use to
  35   * submit it. Once the qustion is submitted, it is not possible for the
  36   * student to change their answer any more, but the student gets full feedback
  37   * straight away.
  38   *
  39   * @copyright  2009 The Open University
  40   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  41   */
  42  class qbehaviour_interactive extends question_behaviour_with_multiple_tries {
  43      /**
  44       * Special value used for {@link question_display_options::$readonly when
  45       * we are showing the try again button to the student during an attempt.
  46       * The particular number was chosen randomly. PHP will treat it the same
  47       * as true, but in the renderer we reconginse it display the try again
  48       * button enabled even though the rest of the question is disabled.
  49       * @var integer
  50       */
  51      const READONLY_EXCEPT_TRY_AGAIN = 23485299;
  52  
  53      public function is_compatible_question(question_definition $question) {
  54          return $question instanceof question_automatically_gradable;
  55      }
  56  
  57      public function can_finish_during_attempt() {
  58          return true;
  59      }
  60  
  61      public function get_right_answer_summary() {
  62          return $this->question->get_right_answer_summary();
  63      }
  64  
  65      /**
  66       * @return bool are we are currently in the try_again state.
  67       */
  68      protected function is_try_again_state() {
  69          $laststep = $this->qa->get_last_step();
  70          return $this->qa->get_state()->is_active() && $laststep->has_behaviour_var('submit') &&
  71                  $laststep->has_behaviour_var('_triesleft');
  72      }
  73  
  74      public function adjust_display_options(question_display_options $options) {
  75          // We only need different behaviour in try again states.
  76          if (!$this->is_try_again_state()) {
  77              parent::adjust_display_options($options);
  78              if ($this->qa->get_state() == question_state::$invalid &&
  79                      $options->marks == question_display_options::MARK_AND_MAX) {
  80                  $options->marks = question_display_options::MAX_ONLY;
  81              }
  82              return;
  83          }
  84  
  85          // Let the hint adjust the options.
  86          $hint = $this->get_applicable_hint();
  87          if (!is_null($hint)) {
  88              $hint->adjust_display_options($options);
  89          }
  90  
  91          // Now call the base class method, but protect some fields from being overwritten.
  92          $save = clone($options);
  93          parent::adjust_display_options($options);
  94          $options->feedback = $save->feedback;
  95          $options->numpartscorrect = $save->numpartscorrect;
  96  
  97          // In a try-again state, everything except the try again button
  98          // Should be read-only. This is a mild hack to achieve this.
  99          if (!$options->readonly) {
 100              $options->readonly = self::READONLY_EXCEPT_TRY_AGAIN;
 101          }
 102      }
 103  
 104      public function get_applicable_hint() {
 105          if (!$this->is_try_again_state()) {
 106              return null;
 107          }
 108          return $this->question->get_hint(count($this->question->hints) -
 109                  $this->qa->get_last_behaviour_var('_triesleft'), $this->qa);
 110      }
 111  
 112      public function get_expected_data() {
 113          if ($this->is_try_again_state()) {
 114              return array(
 115                  'tryagain' => PARAM_BOOL,
 116              );
 117          } else if ($this->qa->get_state()->is_active()) {
 118              return array(
 119                  'submit' => PARAM_BOOL,
 120              );
 121          }
 122          return parent::get_expected_data();
 123      }
 124  
 125      public function get_expected_qt_data() {
 126          $hint = $this->get_applicable_hint();
 127          if (!empty($hint->clearwrong)) {
 128              return $this->question->get_expected_data();
 129          }
 130          return parent::get_expected_qt_data();
 131      }
 132  
 133      public function get_state_string($showcorrectness) {
 134          $state = $this->qa->get_state();
 135          if (!$state->is_active() || $state == question_state::$invalid) {
 136              return parent::get_state_string($showcorrectness);
 137          }
 138  
 139          return get_string('triesremaining', 'qbehaviour_interactive',
 140                  $this->qa->get_last_behaviour_var('_triesleft'));
 141      }
 142  
 143      public function init_first_step(question_attempt_step $step, $variant) {
 144          parent::init_first_step($step, $variant);
 145          $step->set_behaviour_var('_triesleft', count($this->question->hints) + 1);
 146      }
 147  
 148      public function process_action(question_attempt_pending_step $pendingstep) {
 149          if ($pendingstep->has_behaviour_var('finish')) {
 150              return $this->process_finish($pendingstep);
 151          }
 152          if ($this->is_try_again_state()) {
 153              if ($pendingstep->has_behaviour_var('tryagain')) {
 154                  return $this->process_try_again($pendingstep);
 155              } else {
 156                  return question_attempt::DISCARD;
 157              }
 158          } else {
 159              if ($pendingstep->has_behaviour_var('comment')) {
 160                  return $this->process_comment($pendingstep);
 161              } else if ($pendingstep->has_behaviour_var('submit')) {
 162                  return $this->process_submit($pendingstep);
 163              } else {
 164                  return $this->process_save($pendingstep);
 165              }
 166          }
 167      }
 168  
 169      public function summarise_action(question_attempt_step $step) {
 170          if ($step->has_behaviour_var('comment')) {
 171              return $this->summarise_manual_comment($step);
 172          } else if ($step->has_behaviour_var('finish')) {
 173              return $this->summarise_finish($step);
 174          } else if ($step->has_behaviour_var('tryagain')) {
 175              return get_string('tryagain', 'qbehaviour_interactive');
 176          } else if ($step->has_behaviour_var('submit')) {
 177              return $this->summarise_submit($step);
 178          } else {
 179              return $this->summarise_save($step);
 180          }
 181      }
 182  
 183      public function process_try_again(question_attempt_pending_step $pendingstep) {
 184          $pendingstep->set_state(question_state::$todo);
 185          return question_attempt::KEEP;
 186      }
 187  
 188      public function process_submit(question_attempt_pending_step $pendingstep) {
 189          if ($this->qa->get_state()->is_finished()) {
 190              return question_attempt::DISCARD;
 191          }
 192  
 193          if (!$this->is_complete_response($pendingstep)) {
 194              $pendingstep->set_state(question_state::$invalid);
 195  
 196          } else {
 197              $triesleft = $this->qa->get_last_behaviour_var('_triesleft');
 198              $response = $pendingstep->get_qt_data();
 199              list($fraction, $state) = $this->question->grade_response($response);
 200              if ($state == question_state::$gradedright || $triesleft == 1) {
 201                  $pendingstep->set_state($state);
 202                  $pendingstep->set_fraction($this->adjust_fraction($fraction, $pendingstep));
 203  
 204              } else {
 205                  $pendingstep->set_behaviour_var('_triesleft', $triesleft - 1);
 206                  $pendingstep->set_state(question_state::$todo);
 207              }
 208              $pendingstep->set_new_response_summary($this->question->summarise_response($response));
 209          }
 210          return question_attempt::KEEP;
 211      }
 212  
 213      protected function adjust_fraction($fraction, question_attempt_pending_step $pendingstep) {
 214          $totaltries = $this->qa->get_step(0)->get_behaviour_var('_triesleft');
 215          $triesleft = $this->qa->get_last_behaviour_var('_triesleft');
 216  
 217          $fraction -= ($totaltries - $triesleft) * $this->question->penalty;
 218          $fraction = max($fraction, 0);
 219          return $fraction;
 220      }
 221  
 222      public function process_finish(question_attempt_pending_step $pendingstep) {
 223          if ($this->qa->get_state()->is_finished()) {
 224              return question_attempt::DISCARD;
 225          }
 226  
 227          $response = $this->qa->get_last_qt_data();
 228          if (!$this->question->is_gradable_response($response)) {
 229              $pendingstep->set_state(question_state::$gaveup);
 230  
 231          } else {
 232              list($fraction, $state) = $this->question->grade_response($response);
 233              $pendingstep->set_fraction($this->adjust_fraction($fraction, $pendingstep));
 234              $pendingstep->set_state($state);
 235          }
 236          $pendingstep->set_new_response_summary($this->question->summarise_response($response));
 237          return question_attempt::KEEP;
 238      }
 239  
 240      public function process_save(question_attempt_pending_step $pendingstep) {
 241          $status = parent::process_save($pendingstep);
 242          if ($status == question_attempt::KEEP &&
 243                  $pendingstep->get_state() == question_state::$complete) {
 244              $pendingstep->set_state(question_state::$todo);
 245          }
 246          return $status;
 247      }
 248  }