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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 get_right_answer_summary() {
  58          return $this->question->get_right_answer_summary();
  59      }
  60  
  61      /**
  62       * @return bool are we are currently in the try_again state.
  63       */
  64      protected function is_try_again_state() {
  65          $laststep = $this->qa->get_last_step();
  66          return $this->qa->get_state()->is_active() && $laststep->has_behaviour_var('submit') &&
  67                  $laststep->has_behaviour_var('_triesleft');
  68      }
  69  
  70      public function adjust_display_options(question_display_options $options) {
  71          // We only need different behaviour in try again states.
  72          if (!$this->is_try_again_state()) {
  73              parent::adjust_display_options($options);
  74              return;
  75          }
  76  
  77          // Let the hint adjust the options.
  78          $hint = $this->get_applicable_hint();
  79          if (!is_null($hint)) {
  80              $hint->adjust_display_options($options);
  81          }
  82  
  83          // Now call the base class method, but protect some fields from being overwritten.
  84          $save = clone($options);
  85          parent::adjust_display_options($options);
  86          $options->feedback = $save->feedback;
  87          $options->numpartscorrect = $save->numpartscorrect;
  88  
  89          // In a try-again state, everything except the try again button
  90          // Should be read-only. This is a mild hack to achieve this.
  91          if (!$options->readonly) {
  92              $options->readonly = self::READONLY_EXCEPT_TRY_AGAIN;
  93          }
  94      }
  95  
  96      public function get_applicable_hint() {
  97          if (!$this->is_try_again_state()) {
  98              return null;
  99          }
 100          return $this->question->get_hint(count($this->question->hints) -
 101                  $this->qa->get_last_behaviour_var('_triesleft'), $this->qa);
 102      }
 103  
 104      public function get_expected_data() {
 105          if ($this->is_try_again_state()) {
 106              return array(
 107                  'tryagain' => PARAM_BOOL,
 108              );
 109          } else if ($this->qa->get_state()->is_active()) {
 110              return array(
 111                  'submit' => PARAM_BOOL,
 112              );
 113          }
 114          return parent::get_expected_data();
 115      }
 116  
 117      public function get_expected_qt_data() {
 118          $hint = $this->get_applicable_hint();
 119          if (!empty($hint->clearwrong)) {
 120              return $this->question->get_expected_data();
 121          }
 122          return parent::get_expected_qt_data();
 123      }
 124  
 125      public function get_state_string($showcorrectness) {
 126          $state = $this->qa->get_state();
 127          if (!$state->is_active() || $state == question_state::$invalid) {
 128              return parent::get_state_string($showcorrectness);
 129          }
 130  
 131          if ($this->is_try_again_state()) {
 132              return get_string('notcomplete', 'qbehaviour_interactive');
 133          } else {
 134              return get_string('triesremaining', 'qbehaviour_interactive',
 135                      $this->qa->get_last_behaviour_var('_triesleft'));
 136          }
 137      }
 138  
 139      public function init_first_step(question_attempt_step $step, $variant) {
 140          parent::init_first_step($step, $variant);
 141          $step->set_behaviour_var('_triesleft', count($this->question->hints) + 1);
 142      }
 143  
 144      public function process_action(question_attempt_pending_step $pendingstep) {
 145          if ($pendingstep->has_behaviour_var('finish')) {
 146              return $this->process_finish($pendingstep);
 147          }
 148          if ($this->is_try_again_state()) {
 149              if ($pendingstep->has_behaviour_var('tryagain')) {
 150                  return $this->process_try_again($pendingstep);
 151              } else {
 152                  return question_attempt::DISCARD;
 153              }
 154          } else {
 155              if ($pendingstep->has_behaviour_var('comment')) {
 156                  return $this->process_comment($pendingstep);
 157              } else if ($pendingstep->has_behaviour_var('submit')) {
 158                  return $this->process_submit($pendingstep);
 159              } else {
 160                  return $this->process_save($pendingstep);
 161              }
 162          }
 163      }
 164  
 165      public function summarise_action(question_attempt_step $step) {
 166          if ($step->has_behaviour_var('comment')) {
 167              return $this->summarise_manual_comment($step);
 168          } else if ($step->has_behaviour_var('finish')) {
 169              return $this->summarise_finish($step);
 170          } else if ($step->has_behaviour_var('tryagain')) {
 171              return get_string('tryagain', 'qbehaviour_interactive');
 172          } else if ($step->has_behaviour_var('submit')) {
 173              return $this->summarise_submit($step);
 174          } else {
 175              return $this->summarise_save($step);
 176          }
 177      }
 178  
 179      public function process_try_again(question_attempt_pending_step $pendingstep) {
 180          $pendingstep->set_state(question_state::$todo);
 181          return question_attempt::KEEP;
 182      }
 183  
 184      public function process_submit(question_attempt_pending_step $pendingstep) {
 185          if ($this->qa->get_state()->is_finished()) {
 186              return question_attempt::DISCARD;
 187          }
 188  
 189          if (!$this->is_complete_response($pendingstep)) {
 190              $pendingstep->set_state(question_state::$invalid);
 191  
 192          } else {
 193              $triesleft = $this->qa->get_last_behaviour_var('_triesleft');
 194              $response = $pendingstep->get_qt_data();
 195              list($fraction, $state) = $this->question->grade_response($response);
 196              if ($state == question_state::$gradedright || $triesleft == 1) {
 197                  $pendingstep->set_state($state);
 198                  $pendingstep->set_fraction($this->adjust_fraction($fraction, $pendingstep));
 199  
 200              } else {
 201                  $pendingstep->set_behaviour_var('_triesleft', $triesleft - 1);
 202                  $pendingstep->set_state(question_state::$todo);
 203              }
 204              $pendingstep->set_new_response_summary($this->question->summarise_response($response));
 205          }
 206          return question_attempt::KEEP;
 207      }
 208  
 209      protected function adjust_fraction($fraction, question_attempt_pending_step $pendingstep) {
 210          $totaltries = $this->qa->get_step(0)->get_behaviour_var('_triesleft');
 211          $triesleft = $this->qa->get_last_behaviour_var('_triesleft');
 212  
 213          $fraction -= ($totaltries - $triesleft) * $this->question->penalty;
 214          $fraction = max($fraction, 0);
 215          return $fraction;
 216      }
 217  
 218      public function process_finish(question_attempt_pending_step $pendingstep) {
 219          if ($this->qa->get_state()->is_finished()) {
 220              return question_attempt::DISCARD;
 221          }
 222  
 223          $response = $this->qa->get_last_qt_data();
 224          if (!$this->question->is_gradable_response($response)) {
 225              $pendingstep->set_state(question_state::$gaveup);
 226  
 227          } else {
 228              list($fraction, $state) = $this->question->grade_response($response);
 229              $pendingstep->set_fraction($this->adjust_fraction($fraction, $pendingstep));
 230              $pendingstep->set_state($state);
 231          }
 232          $pendingstep->set_new_response_summary($this->question->summarise_response($response));
 233          return question_attempt::KEEP;
 234      }
 235  
 236      public function process_save(question_attempt_pending_step $pendingstep) {
 237          $status = parent::process_save($pendingstep);
 238          if ($status == question_attempt::KEEP &&
 239                  $pendingstep->get_state() == question_state::$complete) {
 240              $pendingstep->set_state(question_state::$todo);
 241          }
 242          return $status;
 243      }
 244  }