<?php  // $Id: questiontype.php,v 1.43.2.19 2009/03/16 01:53:05 tjhunt Exp $
/**
* The default questiontype class.
*
* @version $Id: questiontype.php,v 1.43.2.19 2009/03/16 01:53:05 tjhunt Exp $
* @author Martin Dougiamas and many others. This has recently been completely
*         rewritten by Alex Smith, Julian Sedding and Gustav Delius as part of
*         the Serving Mathematics project
*         {@link http://maths.york.ac.uk/serving_maths}
* @license http://www.gnu.org/copyleft/gpl.html GNU Public License
* @package question
*//** */

require_once($CFG->libdir . '/questionlib.php');

/**
 * This is the base class for Moodle question types.
 *
 * There are detailed comments on each method, explaining what the method is
 * for, and the circumstances under which you might need to override it.
 *
 * Note: the questiontype API should NOT be considered stable yet. Very few
 * question tyeps have been produced yet, so we do not yet know all the places
 * where the current API is insufficient. I would rather learn from the
 * experiences of the first few question type implementors, and improve the
 * interface to meet their needs, rather the freeze the API prematurely and
 * condem everyone to working round a clunky interface for ever afterwards.
 */
class default_questiontype {

    /**
     * Name of the question type
     *
     * The name returned should coincide with the name of the directory
     * in which this questiontype is located
     *
     * @return string the name of this question type.
     */
    function name() {
        return 'default';
    }

    /**
     * The name this question should appear as in the create new question
     * dropdown.
     *
     * @return mixed the desired string, or false to hide this question type in the menu.
     */
    function menu_name() {
        $name = $this->name();
        $menu_name = get_string($name, 'qtype_' . $name);
        if ($menu_name[0] == '[') {
            // Legacy behavior, if the string was not in the proper qtype_name
            // language file, look it up in the quiz one.
            $menu_name = get_string($name, 'quiz');
        }
        return $menu_name;
    }

    /**
     * @return boolean true if this question can only be graded manually.
     */
    function is_manual_graded() {
        return false;
    }

    /**
     * @return boolean true if this question type can be used by the random question type.
     */
    function is_usable_by_random() {
        return true;
    }

    /**
     * @return whether the question_answers.answer field needs to have 
     * restore_decode_content_links_worker called on it.
     */
    function has_html_answers() {
        return false;
    }

    /**
     * Return an instance of the question editing form definition. This looks for a
     * class called edit_{$this->name()}_question_form in the file
     * {$CFG->docroot}/question/type/{$this->name()}/edit_{$this->name()}_question_form.php
     * and if it exists returns an instance of it.
     *
     * @param string $submiturl passed on to the constructor call.
     * @return object an instance of the form definition, or null if one could not be found.
     */
    function create_editing_form($submiturl, $question) {
        global $CFG;
        require_once("{$CFG->dirroot}/question/type/edit_question_form.php");
        $definition_file = $CFG->dirroot.'/question/type/'.$this->name().'/edit_'.$this->name().'_form.php';
        if (!(is_readable($definition_file) && is_file($definition_file))) {
            return null;
        }
        require_once($definition_file);
        $classname = 'question_edit_'.$this->name().'_form';
        if (!class_exists($classname)) {
            return null;
        }
        return new $classname($submiturl, $question);
    }

    /**
     * This method should be overriden if you want to include a special heading or some other
     * html on a question editing page besides the question editing form.
     *
     * @param question_edit_form $mform a child of question_edit_form
     * @param object $question
     * @param string $wizardnow is '' for first page.
     */
    function display_question_editing_page(&$mform, $question, $wizardnow){
        list($heading, $langmodule) = $this->get_heading();
        print_heading_with_help($heading, $this->name(), $langmodule);
        $mform->display();
    }

    /**
     * Method called by display_question_editing_page and by question.php to get heading for breadcrumbs.
     *
     * @return array a string heading and the langmodule in which it was found.
     */
    function get_heading(){
        $name = $this->name();
        $langmodule = 'qtype_' . $name;
        $strtoget = 'editing' . $name;
        $strheading = get_string($strtoget, $langmodule);
        if ($strheading[0] == '[') {
            // Legacy behavior, if the string was not in the proper qtype_name
            // language file, look it up in the quiz one.
            $langmodule = 'quiz';
            $strheading = get_string($strtoget, $langmodule);
        }
        return array($strheading, $langmodule);
    }

    /**
     *
     *
     * @param $question
     */
    function set_default_options(&$question) {
    }

    /**
    * Saves or updates a question after editing by a teacher
    *
    * Given some question info and some data about the answers
    * this function parses, organises and saves the question
    * It is used by {@link question.php} when saving new data from
    * a form, and also by {@link import.php} when importing questions
    * This function in turn calls {@link save_question_options}
    * to save question-type specific options
    * @param object $question the question object which should be updated
    * @param object $form the form submitted by the teacher
    * @param object $course the course we are in
    * @return object On success, return the new question object. On failure,
    *       return an object as follows. If the error object has an errors field,
    *       display that as an error message. Otherwise, the editing form will be
    *       redisplayed with validation errors, from validation_errors field, which
    *       is itself an object, shown next to the form fields.
    */
    function save_question($question, $form, $course) {
        // This default implementation is suitable for most
        // question types.

        // First, save the basic question itself
        if (!record_exists('question_categories', 'id', $form->category)) {
            print_error('categorydoesnotexist', 'question');
        }
        $question->category           = $form->category;
        $question->name               = trim($form->name);
        $question->questiontext       = trim($form->questiontext);
        $question->questiontextformat = $form->questiontextformat;
        $question->parent             = isset($form->parent)? $form->parent : 0;
        $question->length = $this->actual_number_of_questions($question);
        $question->penalty = isset($form->penalty) ? $form->penalty : 0;

        if (empty($form->image)) {
            $question->image = "";
        } else {
            $question->image = $form->image;
        }

        if (empty($form->generalfeedback)) {
            $question->generalfeedback = '';
        } else {
            $question->generalfeedback = trim($form->generalfeedback);
        }

        if (empty($question->name)) {
            $question->name = shorten_text(strip_tags($question->questiontext), 15);
            if (empty($question->name)) {
                $question->name = '-';
            }
        }

        if ($question->penalty > 1 or $question->penalty < 0) {
            $question->errors['penalty'] = get_string('invalidpenalty', 'quiz');
        }

        if (isset($form->defaultgrade)) {
            $question->defaultgrade = $form->defaultgrade;
        }

        if (!empty($question->id)) { // Question already exists
            // keep existing unique stamp code
            $question->stamp = get_field('question', 'stamp', 'id', $question->id);
            if (!update_record("question", $question)) {
                error("Could not update question!");
            }
        } else {         // Question is a new one
            // Set the unique code
            $question->stamp = make_unique_id_code();
            if (!$question->id = insert_record("question", $question)) {
                error("Could not insert new question!");
            }
        }

        // Now to save all the answers and type-specific options

        $form->id = $question->id;
        $form->qtype = $question->qtype;
        $form->category = $question->category;
        $form->questiontext = $question->questiontext;

        $result = $this->save_question_options($form);

        if (!empty($result->error)) {
            error($result->error);
        }

        if (!empty($result->notice)) {
            notice($result->notice, "question.php?id=$question->id");
        }

        if (!empty($result->noticeyesno)) {
            notice_yesno($result->noticeyesno, "question.php?id=$question->id&amp;courseid={$course->id}",
                "edit.php?courseid={$course->id}");
            print_footer($course);
            exit;
        }

        // Give the question a unique version stamp determined by question_hash()
        if (!set_field('question', 'version', question_hash($question), 'id', $question->id)) {
            error('Could not update question version field');
        }

        return $question;
    }

    /**
    * Saves question-type specific options
    *
    * This is called by {@link save_question()} to save the question-type specific data
    * @return object $result->error or $result->noticeyesno or $result->notice
    * @param object $question  This holds the information from the editing form,
    *                          it is not a standard question object.
    */
    function save_question_options($question) {
        return null;
    }

    /**
    * Changes all states for the given attempts over to a new question
    *
    * This is used by the versioning code if the teacher requests that a question
    * gets replaced by the new version. In order for the attempts to be regraded
    * properly all data in the states referring to the old question need to be
    * changed to refer to the new version instead. In particular for question types
    * that use the answers table the answers belonging to the old question have to
    * be changed to those belonging to the new version.
    *
    * @param integer $oldquestionid  The id of the old question
    * @param object $newquestion    The new question
    * @param array  $attempts       An array of all attempt objects in whose states
    *                               replacement should take place
    */
    function replace_question_in_attempts($oldquestionid, $newquestion, $attemtps) {
        echo 'Not yet implemented';
        return;
    }

    /**
    * Loads the question type specific options for the question.
    *
    * This function loads any question type specific options for the
    * question from the database into the question object. This information
    * is placed in the $question->options field. A question type is
    * free, however, to decide on a internal structure of the options field.
    * @return bool            Indicates success or failure.
    * @param object $question The question object for the question. This object
    *                         should be updated to include the question type
    *                         specific information (it is passed by reference).
    */
    function get_question_options(&$question) {
        if (!isset($question->options)) {
            $question->options = new object;
        }
        // The default implementation attaches all answers for this question
        $question->options->answers = get_records('question_answers', 'question', $question->id, 'id ASC');
        return true;
    }

    /**
    * Deletes states from the question-type specific tables
    *
    * @param string $stateslist  Comma separated list of state ids to be deleted
    */
    function delete_states($stateslist) {
        /// The default question type does not have any tables of its own
        // therefore there is nothing to delete

        return true;
    }

    /**
    * Deletes a question from the question-type specific tables
    *
    * @return boolean Success/Failure
    * @param object $question  The question being deleted
    */
    function delete_question($questionid) {
        /// The default question type does not have any tables of its own
        // therefore there is nothing to delete

        return true;
    }

    /**
    * Returns the number of question numbers which are used by the question
    *
    * This function returns the number of question numbers to be assigned
    * to the question. Most question types will have length one; they will be
    * assigned one number. The 'description' type, however does not use up a
    * number and so has a length of zero. Other question types may wish to
    * handle a bundle of questions and hence return a number greater than one.
    * @return integer         The number of question numbers which should be
    *                         assigned to the question.
    * @param object $question The question whose length is to be determined.
    *                         Question type specific information is included.
    */
    function actual_number_of_questions($question) {
        // By default, each question is given one number
        return 1;
    }

    /**
    * Creates empty session and response information for the question
    *
    * This function is called to start a question session. Empty question type
    * specific session data (if any) and empty response data will be added to the
    * state object. Session data is any data which must persist throughout the
    * attempt possibly with updates as the user interacts with the
    * question. This function does NOT create new entries in the database for
    * the session; a call to the {@link save_session_and_responses} member will
    * occur to do this.
    * @return bool            Indicates success or failure.
    * @param object $question The question for which the session is to be
    *                         created. Question type specific information is
    *                         included.
    * @param object $state    The state to create the session for. Note that
    *                         this will not have been saved in the database so
    *                         there will be no id. This object will be updated
    *                         to include the question type specific information
    *                         (it is passed by reference). In particular, empty
    *                         responses will be created in the ->responses
    *                         field.
    * @param object $cmoptions
    * @param object $attempt  The attempt for which the session is to be
    *                         started. Questions may wish to initialize the
    *                         session in different ways depending on the user id
    *                         or time available for the attempt.
    */
    function create_session_and_responses(&$question, &$state, $cmoptions, $attempt) {
        // The default implementation should work for the legacy question types.
        // Most question types with only a single form field for the student's response
        // will use the empty string '' as the index for that one response. This will
        // automatically be stored in and restored from the answer field in the
        // question_states table.
        $state->responses = array(
                '' => '',
        );
        return true;
    }

    /**
    * Restores the session data and most recent responses for the given state
    *
    * This function loads any session data associated with the question
    * session in the given state from the database into the state object.
    * In particular it loads the responses that have been saved for the given
    * state into the ->responses member of the state object.
    *
    * Question types with only a single form field for the student's response
    * will not need not restore the responses; the value of the answer
    * field in the question_states table is restored to ->responses['']
    * before this function is called. Question types with more response fields
    * should override this method and set the ->responses field to an
    * associative array of responses.
    * @return bool            Indicates success or failure.
    * @param object $question The question object for the question including any
    *                         question type specific information.
    * @param object $state    The saved state to load the session for. This
    *                         object should be updated to include the question
    *                         type specific session information and responses
    *                         (it is passed by reference).
    */
    function restore_session_and_responses(&$question, &$state) {
        // The default implementation does nothing (successfully)
        return true;
    }

    /**
    * Saves the session data and responses for the given question and state
    *
    * This function saves the question type specific session data from the
    * state object to the database. In particular for most question types it saves the
    * responses from the ->responses member of the state object. The question type
    * non-specific data for the state has already been saved in the question_states
    * table and the state object contains the corresponding id and
    * sequence number which may be used to index a question type specific table.
    *
    * Question types with only a single form field for the student's response
    * which is contained in ->responses[''] will not have to save this response,
    * it will already have been saved to the answer field of the question_states table.
    * Question types with more response fields should override this method to convert
    * the data the ->responses array into a single string field, and save it in the 
    * database. The implementation in the multichoice question type is a good model to follow.
    * http://cvs.moodle.org/contrib/plugins/question/type/opaque/questiontype.php?view=markup
    * has a solution that is probably quite generally applicable.
    * @return bool            Indicates success or failure.
    * @param object $question The question object for the question including
    *                         the question type specific information.
    * @param object $state    The state for which the question type specific
    *                         data and responses should be saved.
    */
    function save_session_and_responses(&$question, &$state) {
        // The default implementation does nothing (successfully)
        return true;
    }

    /**
    * Returns an array of values which will give full marks if graded as
    * the $state->responses field
    *
    * The correct answer to the question in the given state, or an example of
    * a correct answer if there are many, is returned. This is used by some question
    * types in the {@link grade_responses()} function but it is also used by the
    * question preview screen to fill in correct responses.
    * @return mixed           A response array giving the responses corresponding
    *                         to the (or a) correct answer to the question. If there is
    *                         no correct answer that scores 100% then null is returned.
    * @param object $question The question for which the correct answer is to
    *                         be retrieved. Question type specific information is
    *                         available.
    * @param object $state    The state of the question, for which a correct answer is
    *                         needed. Question type specific information is included.
    */
    function get_correct_responses(&$question, &$state) {
        /* The default implementation returns the response for the first answer
        that gives full marks. */
        if ($question->options->answers) {
            foreach ($question->options->answers as $answer) {
                if (((int) $answer->fraction) === 1) {
                    return array('' => addslashes($answer->answer));
                }
            }
        }
        return null;
    }

    /**
    * Return an array of values with the texts for all possible responses stored
    * for the question
    *
    * All answers are found and their text values isolated
    * @return object          A mixed object
    *             ->id        question id. Needed to manage random questions:
    *                         it's the id of the actual question presented to user in a given attempt
    *             ->responses An array of values giving the responses corresponding
    *                         to all answers to the question. Answer ids are used as keys.
    *                         The text and partial credit are the object components
    * @param object $question The question for which the answers are to
    *                         be retrieved. Question type specific information is
    *                         available.
    */
    // ULPGC ecastro
    function get_all_responses(&$question, &$state) {
        if (isset($question->options->answers) && is_array($question->options->answers)) {
            $answers = array();
            foreach ($question->options->answers as $aid=>$answer) {
                $r = new stdClass;
                $r->answer = $answer->answer;
                $r->credit = $answer->fraction;
                $answers[$aid] = $r;
            }
            $result = new stdClass;
            $result->id = $question->id;
            $result->responses = $answers;
            return $result;
        } else {
            return null;
        }
    }

    /**
    * Return the actual response to the question in a given state
    * for the question.
    *
    * @return mixed           An array containing the response or reponses (multiple answer, match)
    *                         given by the user in a particular attempt.
    * @param object $question The question for which the correct answer is to
    *                         be retrieved. Question type specific information is
    *                         available.
    * @param object $state    The state object that corresponds to the question,
    *                         for which a correct answer is needed. Question
    *                         type specific information is included.
    */
    // ULPGC ecastro
    function get_actual_response($question, $state) {
       // change length to truncate responses here if you want
       $lmax = 40;
       if (!empty($state->responses)) {
           $responses[] = shorten_text(stripslashes($state->responses['']), 45);
       } else {
           $responses[] = '';
       }
       return $responses;
    }

    // ULPGC ecastro
    function get_fractional_grade(&$question, &$state) {
        $maxgrade = $question->maxgrade;
        $grade = $state->grade;
        if ($maxgrade) {
            return (float)($grade/$maxgrade);
        } else {
            return (float)$grade;
        }
    }


    /**
    * Checks if the response given is correct and returns the id
    *
    * @return int             The ide number for the stored answer that matches the response
    *                         given by the user in a particular attempt.
    * @param object $question The question for which the correct answer is to
    *                         be retrieved. Question type specific information is
    *                         available.
    * @param object $state    The state object that corresponds to the question,
    *                         for which a correct answer is needed. Question
    *                         type specific information is included.
    */
    // ULPGC ecastro
    function check_response(&$question, &$state){
        return false;
    }

    /**
    * Prints the question including the number, grading details, content,
    * feedback and interactions
    *
    * This function prints the question including the question number,
    * grading details, content for the question, any feedback for the previously
    * submitted responses and the interactions. The default implementation calls
    * various other methods to print each of these parts and most question types
    * will just override those methods.
    * @param object $question The question to be rendered. Question type
    *                         specific information is included. The
    *                         maximum possible grade is in ->maxgrade. The name
    *                         prefix for any named elements is in ->name_prefix.
    * @param object $state    The state to render the question in. The grading
    *                         information is in ->grade, ->raw_grade and
    *                         ->penalty. The current responses are in
    *                         ->responses. This is an associative array (or the
    *                         empty string or null in the case of no responses
    *                         submitted). The last graded state is in
    *                         ->last_graded (hence the most recently graded
    *                         responses are in ->last_graded->responses). The
    *                         question type specific information is also
    *                         included.
    * @param integer $number  The number for this question.
    * @param object $cmoptions
    * @param object $options  An object describing the rendering options.
    */
    function print_question(&$question, &$state, $number, $cmoptions, $options) {
        /* The default implementation should work for most question types
        provided the member functions it calls are overridden where required.
        The layout is determined by the template question.html */

        global $CFG;
        $isgraded = question_state_is_graded($state->last_graded);

        // If this question is being shown in the context of a quiz
        // get the context so we can determine whether some extra links
        // should be shown. (Don't show these links during question preview.)
        $cm = get_coursemodule_from_instance('quiz', $cmoptions->id);
        if (!empty($cm->id)) {
            $context = get_context_instance(CONTEXT_MODULE, $cm->id);
        } else if (!empty($cm->course)) {
            $context = get_context_instance(CONTEXT_COURSE, $cm->course);
        } else {
            $context = get_context_instance(CONTEXT_SYSTEM, SITEID);
        }

        // For editing teachers print a link to an editing popup window
        $editlink = '';
        if ($context && has_capability('moodle/question:manage', $context)) {
            $stredit = get_string('edit');
            $linktext = '<img src="'.$CFG->pixpath.'/t/edit.gif" alt="'.$stredit.'" />';
            $editlink = link_to_popup_window('/question/question.php?inpopup=1&amp;id=' .
                    $question->id, 'editquestion', $linktext, false, false, $stredit, '', true);
        }

        $generalfeedback = '';
        if ($options->generalfeedback) {
            $generalfeedback = $this->format_text($question->generalfeedback,
                    $question->questiontextformat, $cmoptions);
        }

        $grade = '';
        if ($question->maxgrade and $options->scores) {
            if ($cmoptions->optionflags & QUESTION_ADAPTIVE) {
                $grade = !$isgraded ? '--/' : round($state->last_graded->grade, $cmoptions->decimalpoints).'/';
            }
            $grade .= $question->maxgrade;
        }

        $comment = stripslashes($state->manualcomment);
        $commentlink = '';

        if (isset($options->questioncommentlink) && $context && has_capability('mod/quiz:grade', $context)) {
            $strcomment = get_string('commentorgrade', 'quiz');
            $question_to_comment = isset($question->randomquestionid) ? $question->randomquestionid : $question->id;
            $commentlink = '<div class="commentlink">'.link_to_popup_window ($options->questioncommentlink.'?attempt='.$state->attempt.'&amp;question='.$question_to_comment,
                             'commentquestion', $strcomment, 450, 650, $strcomment, 'none', true).'</div>';
        }

        $history = $this->history($question, $state, $number, $cmoptions, $options);

        include "$CFG->dirroot/question/type/question.html";
    }

    /*
     * Print history of responses
     *
     * Used by print_question()
     */
    function history($question, $state, $number, $cmoptions, $options) {
        $history = '';
        if(isset($options->history) and $options->history) {
            if ($options->history == 'all') {
                // show all states
                $states = get_records_select('question_states', "attempt = '$state->attempt' AND question = '$question->id' AND event > '0'", 'seq_number ASC');
            } else {
                // show only graded states
                $states = get_records_select('question_states', "attempt = '$state->attempt' AND question = '$question->id' AND event IN (".QUESTION_EVENTGRADE.','.QUESTION_EVENTCLOSEANDGRADE.")", 'seq_number ASC');
            }
            if (count($states) > 1) {
                $strreviewquestion = get_string('reviewresponse', 'quiz');
                $table = new stdClass;
                $table->width = '100%';
                if ($options->scores) {
                    $table->head  = array (
                                           get_string('numberabbr', 'quiz'),
                                           get_string('action', 'quiz'),
                                           get_string('response', 'quiz'),
                                           get_string('time'),
                                           get_string('score', 'quiz'),
                                           //get_string('penalty', 'quiz'),
                                           get_string('grade', 'quiz'),
                                           );
                } else {
                    $table->head  = array (
                                           get_string('numberabbr', 'quiz'),
                                           get_string('action', 'quiz'),
                                           get_string('response', 'quiz'),
                                           get_string('time'),
                                           );
                }

                foreach ($states as $st) {
                    $st->responses[''] = $st->answer;
                    $this->restore_session_and_responses($question, $st);
                    $b = ($state->id == $st->id) ? '<b>' : '';
                    $be = ($state->id == $st->id) ? '</b>' : '';
                    if ($state->id == $st->id) {
                        $link = '<b>'.$st->seq_number.'</b>';
                    } else {
                        if(isset($options->questionreviewlink)) {
                            $link = link_to_popup_window ($options->questionreviewlink.'?state='.$st->id.'&amp;number='.$number,
                             'reviewquestion', $st->seq_number, 450, 650, $strreviewquestion, 'none', true);
                        } else {
                            $link = $st->seq_number;
                        }
                    }
                    if ($options->scores) {
                        $table->data[] = array (
                                                $link,
                                                $b.get_string('event'.$st->event, 'quiz').$be,
                                                $b.$this->response_summary($question, $st).$be,
                                                $b.userdate($st->timestamp, get_string('timestr', 'quiz')).$be,
                                                $b.round($st->raw_grade, $cmoptions->decimalpoints).$be,
                                                //$b.round($st->penalty, $cmoptions->decimalpoints).$be,
                                                $b.round($st->grade, $cmoptions->decimalpoints).$be
                                                );
                    } else {
                        $table->data[] = array (
                                                $link,
                                                $b.get_string('event'.$st->event, 'quiz').$be,
                                                $b.$this->response_summary($question, $st).$be,
                                                $b.userdate($st->timestamp, get_string('timestr', 'quiz')).$be,
                                                );
                    }
                }
                $history = make_table($table);
            }
        }
        return $history;
    }


    /**
    * Prints the score obtained and maximum score available plus any penalty
    * information
    *
    * This function prints a summary of the scoring in the most recently
    * graded state (the question may not have been submitted for marking at
    * the current state). The default implementation should be suitable for most
    * question types.
    * @param object $question The question for which the grading details are
    *                         to be rendered. Question type specific information
    *                         is included. The maximum possible grade is in
    *                         ->maxgrade.
    * @param object $state    The state. In particular the grading information
    *                          is in ->grade, ->raw_grade and ->penalty.
    * @param object $cmoptions
    * @param object $options  An object describing the rendering options.
    */
    function print_question_grading_details(&$question, &$state, $cmoptions, $options) {
        /* The default implementation prints the number of marks if no attempt
        has been made. Otherwise it displays the grade obtained out of the
        maximum grade available and a warning if a penalty was applied for the
        attempt and displays the overall grade obtained counting all previous
        responses (and penalties) */

        if (QUESTION_EVENTDUPLICATE == $state->event) {
            echo ' ';
            print_string('duplicateresponse', 'quiz');
        }
        if (!empty($question->maxgrade) && $options->scores) {
            if (question_state_is_graded($state->last_graded)) {
                // Display the grading details from the last graded state
                $grade = new stdClass;
                $grade->cur = round($state->last_graded->grade, $cmoptions->decimalpoints);
                $grade->max = $question->maxgrade;
                $grade->raw = round($state->last_graded->raw_grade, $cmoptions->decimalpoints);

                // let student know wether the answer was correct
                echo '<div class="correctness ';
                if ($state->last_graded->raw_grade >= $question->maxgrade/1.01) { // We divide by 1.01 so that rounding errors dont matter.
                    echo ' correct">';
                    print_string('correct', 'quiz');
                } else if ($state->last_graded->raw_grade > 0) {
                    echo ' partiallycorrect">';
                    print_string('partiallycorrect', 'quiz');
                } else {
                    echo ' incorrect">';
                    print_string('incorrect', 'quiz');
                }
                echo '</div>';

                echo '<div class="gradingdetails">';
                // print grade for this submission
                print_string('gradingdetails', 'quiz', $grade);
                if ($cmoptions->penaltyscheme) {
                    // print details of grade adjustment due to penalties
                    if ($state->last_graded->raw_grade > $state->last_graded->grade){
                        echo ' ';
                        print_string('gradingdetailsadjustment', 'quiz', $grade);
                    }
                    // print info about new penalty
                    // penalty is relevant only if the answer is not correct and further attempts are possible
                    if (($state->last_graded->raw_grade < $question->maxgrade / 1.01)
                                and (QUESTION_EVENTCLOSEANDGRADE != $state->event)) {

                        if ('' !== $state->last_graded->penalty && ((float)$state->last_graded->penalty) > 0.0) {
                            // A penalty was applied so display it
                            echo ' ';
                            print_string('gradingdetailspenalty', 'quiz', $state->last_graded->penalty);
                        } else {
                            /* No penalty was applied even though the answer was
                            not correct (eg. a syntax error) so tell the student
                            that they were not penalised for the attempt */
                            echo ' ';
                            print_string('gradingdetailszeropenalty', 'quiz');
                        }
                    }
                }
                echo '</div>';
            }
        }
    }

    /**
    * Prints the main content of the question including any interactions
    *
    * This function prints the main content of the question including the
    * interactions for the question in the state given. The last graded responses
    * are printed or indicated and the current responses are selected or filled in.
    * Any names (eg. for any form elements) are prefixed with $question->name_prefix.
    * This method is called from the print_question method.
    * @param object $question The question to be rendered. Question type
    *                         specific information is included. The name
    *                         prefix for any named elements is in ->name_prefix.
    * @param object $state    The state to render the question in. The grading
    *                         information is in ->grade, ->raw_grade and
    *                         ->penalty. The current responses are in
    *                         ->responses. This is an associative array (or the
    *                         empty string or null in the case of no responses
    *                         submitted). The last graded state is in
    *                         ->last_graded (hence the most recently graded
    *                         responses are in ->last_graded->responses). The
    *                         question type specific information is also
    *                         included.
    *                         The state is passed by reference because some adaptive
    *                         questions may want to update it during rendering
    * @param object $cmoptions
    * @param object $options  An object describing the rendering options.
    */
    function print_question_formulation_and_controls(&$question, &$state, $cmoptions, $options) {
        /* This default implementation prints an error and must be overridden
        by all question type implementations, unless the default implementation
        of print_question has been overridden. */

        notify('Error: Question formulation and input controls has not'
               .'  been implemented for question type '.$this->name());
    }

    /**
    * Prints the submit button(s) for the question in the given state
    *
    * This function prints the submit button(s) for the question in the
    * given state. The name of any button created will be prefixed with the
    * unique prefix for the question in $question->name_prefix. The suffix
    * 'submit' is reserved for the single question submit button and the suffix
    * 'validate' is reserved for the single question validate button (for
    * question types which support it). Other suffixes will result in a response
    * of that name in $state->responses which the printing and grading methods
    * can then use.
    * @param object $question The question for which the submit button(s) are to
    *                         be rendered. Question type specific information is
    *                         included. The name prefix for any
    *                         named elements is in ->name_prefix.
    * @param object $state    The state to render the buttons for. The
    *                         question type specific information is also
    *                         included.
    * @param object $cmoptions
    * @param object $options  An object describing the rendering options.
    */
    function print_question_submit_buttons(&$question, &$state, $cmoptions, $options) {
        /* The default implementation should be suitable for most question
        types. It prints a mark button in the case where individual marking is
        allowed. */

        if (($cmoptions->optionflags & QUESTION_ADAPTIVE) and !$options->readonly) {
            echo '<input type="submit" name="';
            echo $question->name_prefix;
            echo 'submit" value="';
            print_string('mark', 'quiz');
            echo '" class="submit btn"';
            echo ' />';
        }
    }


    /**
    * Return a summary of the student response
    *
    * This function returns a short string of no more than a given length that
    * summarizes the student's response in the given $state. This is used for
    * example in the response history table. This string should already be,
    * for output.
    * @return string         The summary of the student response
    * @param object $question
    * @param object $state   The state whose responses are to be summarized
    * @param int $length     The maximum length of the returned string
    */
    function response_summary($question, $state, $length=80) {
        // This should almost certainly be overridden
        $responses = $this->get_actual_response($question, $state);
        if (empty($responses) || !is_array($responses)) {
            $responses = array();
        }
        if (is_array($responses)) {
            $responses = implode(',', array_map('s', $responses));
        }
        return shorten_text($responses, $length);
    }

    /**
    * Renders the question for printing and returns the LaTeX source produced
    *
    * This function should render the question suitable for a printed problem
    * or solution sheet in LaTeX and return the rendered output.
    * @return string          The LaTeX output.
    * @param object $question The question to be rendered. Question type
    *                         specific information is included.
    * @param object $state    The state to render the question in. The
    *                         question type specific information is also
    *                         included.
    * @param object $cmoptions
    * @param string $type     Indicates if the question or the solution is to be
    *                         rendered with the values 'question' and
    *                         'solution'.
    */
    function get_texsource(&$question, &$state, $cmoptions, $type) {
        // The default implementation simply returns a string stating that
        // the question is only available online.

        return get_string('onlineonly', 'texsheet');
    }

    /**
    * Compares two question states for equivalence of the student's responses
    *
    * The responses for the two states must be examined to see if they represent
    * equivalent answers to the question by the student. This method will be
    * invoked for each of the previous states of the question before grading
    * occurs. If the student is found to have already attempted the question
    * with equivalent responses then the attempt at the question is ignored;
    * grading does not occur and the state does not change. Thus they are not
    * penalized for this case.
    * @return boolean
    * @param object $question  The question for which the states are to be
    *                          compared. Question type specific information is
    *                          included.
    * @param object $state     The state of the question. The responses are in
    *                          ->responses. This is the only field of $state
    *                          that it is safe to use.
    * @param object $teststate The state whose responses are to be
    *                          compared. The state will be of the same age or
    *                          older than $state. If possible, the method should
    *                          only use the field $teststate->responses, however
    *                          any field that is set up by restore_session_and_responses
    *                          can be used.
    */
    function compare_responses(&$question, $state, $teststate) {
        // The default implementation performs a comparison of the response
        // arrays. The ordering of the arrays does not matter.
        // Question types may wish to override this (eg. to ignore trailing
        // white space or to make "7.0" and "7" compare equal).

        // In php neither == nor === compare arrays the way you want. The following 
        // ensures that the arrays have the same keys, with the same values.
        $result = false;
        $diff1 = array_diff_assoc($state->responses, $teststate->responses);
        if (empty($diff1)) {
            $diff2 = array_diff_assoc($teststate->responses, $state->responses);
            $result =  empty($diff2);
        }

        return $result;
    }

    /**
    * Checks whether a response matches a given answer
    *
    * This method only applies to questions that use teacher-defined answers
    *
    * @return boolean
    */
    function test_response(&$question, &$state, $answer) {
        $response = isset($state->responses['']) ? $state->responses[''] : '';
        return ($response == $answer->answer);
    }

    /**
    * Performs response processing and grading
    *
    * This function performs response processing and grading and updates
    * the state accordingly.
    * @return boolean         Indicates success or failure.
    * @param object $question The question to be graded. Question type
    *                         specific information is included.
    * @param object $state    The state of the question to grade. The current
    *                         responses are in ->responses. The last graded state
    *                         is in ->last_graded (hence the most recently graded
    *                         responses are in ->last_graded->responses). The
    *                         question type specific information is also
    *                         included. The ->raw_grade and ->penalty fields
    *                         must be updated. The method is able to
    *                         close the question session (preventing any further
    *                         attempts at this question) by setting
    *                         $state->event to QUESTION_EVENTCLOSEANDGRADE
    * @param object $cmoptions
    */
    function grade_responses(&$question, &$state, $cmoptions) {
        // The default implementation uses the test_response method to
        // compare what the student entered against each of the possible
        // answers stored in the question, and uses the grade from the
        // first one that matches. It also sets the marks and penalty.
        // This should be good enought for most simple question types.

        $state->raw_grade = 0;
        foreach($question->options->answers as $answer) {
            if($this->test_response($question, $state, $answer)) {
                $state->raw_grade = $answer->fraction;
                break;
            }
        }

        // Make sure we don't assign negative or too high marks.
        $state->raw_grade = min(max((float) $state->raw_grade,
                            0.0), 1.0) * $question->maxgrade;

        // Update the penalty.
        $state->penalty = $question->penalty * $question->maxgrade;

        // mark the state as graded
        $state->event = ($state->event ==  QUESTION_EVENTCLOSE) ? QUESTION_EVENTCLOSEANDGRADE : QUESTION_EVENTGRADE;

        return true;
    }


    /**
    * Includes configuration settings for the question type on the quiz admin
    * page
    *
    * TODO: It makes no sense any longer to do the admin for question types
    * from the quiz admin page. This should be changed.
    * Returns an array of objects describing the options for the question type
    * to be included on the quiz module admin page.
    * Configuration options can be included by setting the following fields in
    * the object:
    * ->name           The name of the option within this question type.
    *                  The full option name will be constructed as
    *                  "quiz_{$this->name()}_$name", the human readable name
    *                  will be displayed with get_string($name, 'quiz').
    * ->code           The code to display the form element, help button, etc.
    *                  i.e. the content for the central table cell. Be sure
    *                  to name the element "quiz_{$this->name()}_$name" and
    *                  set the value to $CFG->{"quiz_{$this->name()}_$name"}.
    * ->help           Name of the string from the quiz module language file
    *                  to be used for the help message in the third column of
    *                  the table. An empty string (or the field not set)
    *                  means to leave the box empty.
    * Links to custom settings pages can be included by setting the following
    * fields in the object:
    * ->name           The name of the link text string.
    *                  get_string($name, 'quiz') will be called.
    * ->link           The filename part of the URL for the link. The full URL
    *                  is contructed as
    *                  "$CFG->wwwroot/question/type/{$this->name()}/$link?sesskey=$sesskey"
    *                  [but with the relavant calls to the s and rawurlencode
    *                  functions] where $sesskey is the sesskey for the user.
    * @return array    Array of objects describing the configuration options to
    *                  be included on the quiz module admin page.
    */
    function get_config_options() {
        // No options by default

        return false;
    }

    /**
    * Returns true if the editing wizard is finished, false otherwise.
    *
    * The default implementation returns true, which is suitable for all question-
    * types that only use one editing form. This function is used in
    * question.php to decide whether we can regrade any states of the edited
    * question and redirect to edit.php.
    *
    * The dataset dependent question-type, which is extended by the calculated
    * question-type, overwrites this method because it uses multiple pages (i.e.
    * a wizard) to set up the question and associated datasets.
    *
    * @param object $form  The data submitted by the previous page.
    *
    * @return boolean      Whether the wizard's last page was submitted or not.
    */
    function finished_edit_wizard(&$form) {
        //In the default case there is only one edit page.
        return true;
    }

    /**
    * Prints a table of course modules in which the question is used
    *
    * TODO: This should be made quiz-independent
    *
    * This function is used near the end of the question edit forms in all question types
    * It prints the table of quizzes in which the question is used
    * containing checkboxes to allow the teacher to replace the old question version
    *
    * @param object $question
    * @param object $course
    * @param integer $cmid optional The id of the course module currently being edited
    */
    function print_replacement_options($question, $course, $cmid='0') {

        // Disable until the versioning code has been fixed
        if (true) {
            return;
        }

        // no need to display replacement options if the question is new
        if(empty($question->id)) {
            return true;
        }

        // get quizzes using the question (using the question_instances table)
        $quizlist = array();
        if(!$instances = get_records('quiz_question_instances', 'question', $question->id)) {
            $instances = array();
        }
        foreach($instances as $instance) {
            $quizlist[$instance->quiz] = $instance->quiz;
        }
        $quizlist = implode(',', $quizlist);
        if(empty($quizlist) or !$quizzes = get_records_list('quiz', 'id', $quizlist)) {
            $quizzes = array();
        }

        // do the printing
        if(count($quizzes) > 0) {
            // print the table
            $strquizname  = get_string('modulename', 'quiz');
            $strdoreplace = get_string('replace', 'quiz');
            $straffectedstudents = get_string('affectedstudents', 'quiz', $course->students);
            echo "<tr valign=\"top\">\n";
            echo "<td align=\"right\"><b>".get_string("replacementoptions", "quiz").":</b></td>\n";
            echo "<td align=\"left\">\n";
            echo "<table cellpadding=\"5\" align=\"left\" class=\"generalbox\" width=\"100%\">\n";
            echo "<tr>\n";
            echo "<th align=\"left\" valign=\"top\" nowrap=\"nowrap\" class=\"generaltableheader c0\" scope=\"col\">$strquizname</th>\n";
            echo "<th align=\"center\" valign=\"top\" nowrap=\"nowrap\" class=\"generaltableheader c0\" scope=\"col\">$strdoreplace</th>\n";
            echo "<th align=\"left\" valign=\"top\" nowrap=\"nowrap\" class=\"generaltableheader c0\" scope=\"col\">$straffectedstudents</th>\n";
            echo "</tr>\n";
            foreach($quizzes as $quiz) {
                // work out whethere it should be checked by default
                $checked = '';
                if((int)$cmid === (int)$quiz->id
                    or empty($quiz->usercount)) {
                    $checked = "checked=\"checked\"";
                }

                // find how many different students have already attempted this quiz
                $students = array();
                if($attempts = get_records_select('quiz_attempts', "quiz = '$quiz->id' AND preview = '0'")) {
                    foreach($attempts as $attempt) {
                        if (record_exists('question_states', 'attempt', $attempt->uniqueid, 'question', $question->id, 'originalquestion', 0)) {
                            $students[$attempt->userid] = 1;
                        }
                    }
                }
                $studentcount = count($students);

                $strstudents = $studentcount === 1 ? $course->student : $course->students;
                echo "<tr>\n";
                echo "<td align=\"left\" class=\"generaltablecell c0\">".format_string($quiz->name)."</td>\n";
                echo "<td align=\"center\" class=\"generaltablecell c0\"><input name=\"q{$quiz->id}replace\" type=\"checkbox\" ".$checked." /></td>\n";
                echo "<td align=\"left\" class=\"generaltablecell c0\">".(($studentcount) ? $studentcount.' '.$strstudents : '-')."</td>\n";
                echo "</tr>\n";
            }
            echo "</table>\n";
        }
        echo "</td></tr>\n";
    }

    /**
     * Print the start of the question editing form, including the question category,
     * questionname, questiontext, image, defaultgrade, penalty and generalfeedback fields.
     *
     * Three of the fields, image, defaultgrade, penalty, are optional, and
     * can be removed from the from using the $hidefields argument.
     *
     * @param object $question The question object that the form we are printing is for.
     * @param array $err Array of optional error messages to display by each field.
     *          Used when the form is being redisplayed after validation failed.
     * @param object $course The course object for the course this question belongs to.
     * @param boolean $usehtmleditor Whether the html editor should be used.
     * @param array $hidefields An array which may contain the strings,
     *          'image', 'defaultgrade' or 'penalty' to remove the corresponding field.
     */
    function print_question_form_start($question, $err, $course, $usehtmleditor, $hidefields = array()) {
        global $CFG;

        // If you edit this function, you also need to edit random/editquestion.html.

        if (!in_array('image', $hidefields)) {
            make_upload_directory("$course->id");    // Just in case
            $coursefiles = get_directory_list("$CFG->dataroot/$course->id", $CFG->moddata);
            foreach ($coursefiles as $filename) {
                if (mimeinfo("icon", $filename) == "image.gif") {
                    $images["$filename"] = $filename;
                }
            }
        }

        include('editquestionstart.html');
    }

    /**
     * Print the end of the question editing form, including the submit, copy,
     * and cancel button, and the standard hidden fields like the sesskey and
     * the question type.
     *
     * @param object $question The question object that the form we are printing is for.
     * @param string $submitscript Extra attributes, for example 'onsubmit="myfunction"',
     *          that is added to the HTML of the submit button.
     * @param string $hiddenfields Extra hidden fields (actually any HTML)
     *          to be added at the end of the form.
     */
    function print_question_form_end($question, $submitscript = '', $hiddenfields = '') {
        global $USER;

        // If you edit this function, you also need to edit random/editquestion.html.

        include('editquestionend.html');
    }

    /**
     * Call format_text from weblib.php with the options appropriate to question types.
     *
     * @param string $text the text to format.
     * @param integer $text the type of text. Normally $question->questiontextformat.
     * @param object $cmoptions the context the string is being displayed in. Only $cmoptions->course is used.
     * @return string the formatted text.
     */
    function format_text($text, $textformat, $cmoptions = NULL) {
        $formatoptions = new stdClass;
        $formatoptions->noclean = true;
        $formatoptions->para = false;
        return format_text($text, $textformat, $formatoptions, $cmoptions === NULL ? NULL : $cmoptions->course);
    }

/// BACKUP FUNCTIONS ////////////////////////////

    /*
     * Backup the data in the question
     *
     * This is used in question/backuplib.php
     */
    function backup($bf,$preferences,$question,$level=6) {
        // The default type has nothing to back up
        return true;
    }

/// RESTORE FUNCTIONS /////////////////

    /*
     * Restores the data in the question
     *
     * This is used in question/restorelib.php
     */
    function restore($old_question_id,$new_question_id,$info,$restore) {
        // The default question type has nothing to restore
        return true;
    }

    function restore_map($old_question_id,$new_question_id,$info,$restore) {
        // There is nothing to decode
        return true;
    }

    function restore_recode_answer($state, $restore) {
        // There is nothing to decode
        return $state->answer;
    }

    //This function restores the question_rqp_states
    function restore_state($state_id,$info,$restore) {
        // The default question type does not keep its own state information
        return true;
    }

}

?>
