MDL-14203 "split report into two seperate reports - Quiz Statistics report and Indivi...

[moodle.git] / mod / quiz / report / statistics / report.php

<?php
/**
 * This script lists student attempts
 *
 * @version $Id$
 * @author Martin Dougiamas, Tim Hunt and others.
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 * @package quiz
 *//** */

require_once($CFG->libdir.'/tablelib.php');
require_once($CFG->dirroot.'/mod/quiz/report/statistics/statistics_form.php');
require_once($CFG->dirroot.'/mod/quiz/report/statistics/statistics_table.php');

class quiz_report extends quiz_default_report {

    /**
     * Display the report.
     */
    function display($quiz, $cm, $course) {
        global $CFG, $DB;

        $context = get_context_instance(CONTEXT_MODULE, $cm->id);

        $download = optional_param('download', '', PARAM_ALPHA);

        $pageoptions = array();
        $pageoptions['id'] = $cm->id;
        $pageoptions['q'] = $quiz->id;
        $pageoptions['mode'] = 'statistics';

        $reporturl = new moodle_url($CFG->wwwroot.'/mod/quiz/report.php', $pageoptions);

        $mform = new mod_quiz_report_statistics($reporturl);
        if ($fromform = $mform->get_data()){
            $useallattempts = $fromform->useallattempts;
            if ($fromform->useallattempts){
                set_user_preference('quiz_report_statistics_useallattempts', $fromform->useallattempts);
            } else {
                unset_user_preference('quiz_report_statistics_useallattempts');
            }
        } else {
            $useallattempts = get_user_preferences('quiz_report_statistics_useallattempts', 0);
        }

        /// find out current groups mode
        $currentgroup = groups_get_activity_group($cm, true);

        if (!empty($currentgroup)) {
            // all users who can attempt quizzes and who are in the currently selected group
            if (!$groupstudents = get_users_by_capability($context, 'mod/quiz:attempt','','','','',$currentgroup,'',false)){
                $groupstudents = array();
            }
            $groupstudentslist = join(',', array_keys($groupstudents));
            $allowedlist = $groupstudentslist;
        }

        $questions = quiz_report_load_questions($quiz);

        $table = new quiz_report_statistics_table($quiz , $questions, $reporturl);
        $table->is_downloading($download, get_string('reportstatistics','quiz_statistics'),
                    "$course->shortname ".format_string($quiz->name,true));
        if (!$table->is_downloading()) {
            // Only print headers if not asked to download data
            $this->print_header_and_tabs($cm, $course, $quiz, "statistics");
        }

        if ($groupmode = groups_get_activity_groupmode($cm)) {   // Groups are being used
            if (!$table->is_downloading()) {
                groups_print_activity_menu($cm, $reporturl->out());
            }
        }

        
        // Print information on the number of existing attempts
        if (!$table->is_downloading()) { //do not print notices when downloading
            print_heading(get_string('quizinformation', 'quiz_statistics'));
            $quizinformationtable = new object();
            $quizinformationtable->align = array('center', 'center');
            $quizinformationtable->width = '60%';
            $quizinformationtable->class = 'generaltable titlesleft';
            $quizinformationtable->data = array();
            $quizinformationtable->data[] = array(get_string('quizname', 'quiz_statistics'), $quiz->name);
            $quizinformationtable->data[] = array(get_string('coursename', 'quiz_statistics'), $course->fullname);
            if ($cm->idnumber){
                $quizinformationtable->data[] = array(get_string('coursename', 'quiz_statistics'), $cm->idnumber);
            }
            if ($quiz->timeopen){
                $quizinformationtable->data[] = array(get_string('quizopen', 'quiz'), userdate($quiz->timeopen));
            }
            if ($quiz->timeclose){
                $quizinformationtable->data[] = array(get_string('quizclose', 'quiz'), userdate($quiz->timeclose));
            }
            if ($quiz->timeopen && $quiz->timeclose){
                $quizinformationtable->data[] = array(get_string('duration'), format_time($quiz->timeclose - $quiz->timeopen));
            }
            print_table($quizinformationtable);
        }
        if (!$table->is_downloading()) {
            // Print display options
            $mform->set_data(array('useallattempts' => $useallattempts));
            $mform->display();
        }
        
        $sql = 'SELECT (attempt=1) AS isfirst, COUNT(1) AS countrecs, SUM(sumgrades) AS total ' .
                'FROM {quiz_attempts} ' .
                'WHERE quiz = :quiz AND preview=0 AND timefinish !=0 ' .
                'GROUP BY (attempt=1)';

        if (!$attempttotals = $DB->get_records_sql($sql, array('quiz' => $quiz->id))){
            print_heading(get_string('noattempts','quiz'));
            return true;
        } else {
            $firstattempt = $attempttotals[1];
            $allattempts = new object();
            $allattempts->countrecs = $firstattempt->countrecs + 
                            (isset($attempttotals[0])?$attempttotals[0]->countrecs:0);
            $allattempts->total = $firstattempt->total + 
                            (isset($attempttotals[0])?$attempttotals[0]->total:0);
        }
        
        if (!$table->is_downloading()) {
            print_heading(get_string('quizoverallstatistics', 'quiz_statistics'));
            $quizoverallstatistics = new object();
            $quizoverallstatistics->align = array('center', 'center');
            $quizoverallstatistics->width = '60%';
            $quizoverallstatistics->class = 'generaltable titlesleft';
            $quizoverallstatistics->data = array();
            $quizoverallstatistics->data[] = array(get_string('nooffirstattempts', 'quiz_statistics'), $firstattempt->countrecs);
            $quizoverallstatistics->data[] = array(get_string('noofallattempts', 'quiz_statistics'), $allattempts->countrecs);
            $quizoverallstatistics->data[] = array(get_string('firstattemptsavg', 'quiz_statistics'), quiz_report_scale_sumgrades_as_percentage($firstattempt->total / $firstattempt->countrecs, $quiz));
            $quizoverallstatistics->data[] = array(get_string('allattemptsavg', 'quiz_statistics'), quiz_report_scale_sumgrades_as_percentage($allattempts->total / $allattempts->countrecs, $quiz));
            print_table($quizoverallstatistics);
        }
        //get the median
        
        
        if (!$table->is_downloading()) {
            if ($useallattempts){
                $usingattempts = $allattempts;
                $usingattempts->heading = get_string('statsforallattempts', 'quiz_statistics');
                $usingattempts->sql = '';
            } else {
                $usingattempts = $firstattempt;
                $usingattempts->heading = get_string('statsforfirstattempts', 'quiz_statistics');
                $usingattempts->sql = 'AND attempt=1 ';
            }
            print_heading($usingattempts->heading);
            if (($usingattempts->countrecs/2)==floor($usingattempts->countrecs/2)){
                //even number of attempts
                $limitoffset = (floor($usingattempts->countrecs/2)) - 1;
                $limit = 2;
            } else {
                $limitoffset = ($usingattempts->countrecs/2) - 1;
                $limit = 1;
            }
            $sql = 'SELECT id, sumgrades ' .
                'FROM {quiz_attempts} ' .
                'WHERE quiz = :quiz AND preview=0 AND timefinish !=0 ' .
                $usingattempts->sql.
                'ORDER BY sumgrades';
            if (!$mediangrades = $DB->get_records_sql_menu($sql, array('quiz' => $quiz->id), $limitoffset, $limit)){
                print_error('errormedian', 'quiz_statistics');
            }
            if (count($mediangrades)==1){
                $median = array_shift($mediangrades);
            } else {
                $median = array_shift($mediangrades);
                $median += array_shift($mediangrades);
                $median = $median /2;
            }
            //fetch sum of squared, cubed and power 4d 
            //differences between grades and mean grade
            $mean = $usingattempts->total / $usingattempts->countrecs;
            $sql = "SELECT " .
                "SUM(POWER((sumgrades - ?),2)) AS power2, " .
                "SUM(POWER((sumgrades - ?),3)) AS power3, ".
                "SUM(POWER((sumgrades - ?),4)) AS power4 ".
                "FROM {quiz_attempts} " .
                "WHERE quiz = ? AND preview=0 AND timefinish !=0 " .
                $usingattempts->sql.
                "ORDER BY sumgrades";
            $params = array($mean, $mean, $mean, $quiz->id);
            if (!$powers = $DB->get_record_sql($sql, $params)){
                print_error('errorpowers', 'quiz_statistics');
            }
            
            $s = $usingattempts->countrecs;
            
            $sd = sqrt($powers->power2 / ($s -1));
            
            $m2= $powers->power2 / $s;
            $m3= $powers->power3 / $s;
            $m4= $powers->power4 / $s;
            
            $k2= $s*$m2/($s-1);
            $k3= $s*$s*$m3/(($s-1)*($s-2));
            $k3= $s*$s*$s*$m3/(($s-1)*($s-2)*($s-3));
            $k4= $s*$s*$s*(($s+1)*$m4-3*($s-1)*$m2*$m2)/(($s-1)*($s-2)*($s-3));
            
            $skewness = $k3 / (pow($k2, 2/3));
            $kurtosis = $k4 / ($k2*$k2);
            
            $quizattsstatistics = new object();
            $quizattsstatistics->align = array('center', 'center');
            $quizattsstatistics->width = '60%';
            $quizattsstatistics->class = 'generaltable titlesleft';
            $quizattsstatistics->data = array();
            
            $quizattsstatistics->data[] = array(get_string('median', 'quiz_statistics'), quiz_report_scale_sumgrades_as_percentage($median, $quiz));
            $quizattsstatistics->data[] = array(get_string('standarddeviation', 'quiz_statistics'), quiz_report_scale_sumgrades_as_percentage($sd, $quiz));
            $quizattsstatistics->data[] = array(get_string('skewness', 'quiz_statistics'), $skewness);
            $quizattsstatistics->data[] = array(get_string('kurtosis', 'quiz_statistics'), $kurtosis);
            print_table($quizattsstatistics);
        }

        return true;
    }

}


?>