Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace quiz_statistics;

defined('MOODLE_INTERNAL') || die();

/**

 * The statistics calculator returns an instance of this class which contains the calculated statistics.

 *

 * These quiz statistics calculations are described here :

 *

 * http://docs.moodle.org/dev/Quiz_statistics_calculations#Test_statistics

 *

 * @package    quiz_statistics

 * @copyright  2013 The Open University

 * @author     James Pratt me@jamiep.org

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class calculated {

    /**

     * @param  string $whichattempts which attempts to use, represented internally as one of the constants as used in

     *                                   $quiz->grademethod ie.

     *                                   QUIZ_GRADEAVERAGE, QUIZ_GRADEHIGHEST, QUIZ_ATTEMPTLAST or QUIZ_ATTEMPTFIRST

     *                                   we calculate stats based on which attempts would affect the grade for each student,

     *                                   the default null value is used when constructing an instance whose values will be

     *                                   populated from a db record.

     */

    public function __construct($whichattempts = null) {

        if ($whichattempts !== null) {

            $this->whichattempts = $whichattempts;

        }

    }

    /**

     * @var int which attempts we are calculating calculate stats from.

     */

    public $whichattempts;

    /* Following stats all described here : http://docs.moodle.org/dev/Quiz_statistics_calculations#Test_statistics  */

    public $firstattemptscount = 0;

    public $allattemptscount = 0;

    public $lastattemptscount = 0;

    public $highestattemptscount = 0;

    public $firstattemptsavg;

    public $allattemptsavg;

    public $lastattemptsavg;

    public $highestattemptsavg;

    public $median;

    public $standarddeviation;

    public $skewness;

    public $kurtosis;

    public $cic;

    public $errorratio;

    public $standarderror;

    /**

     * @var int time these stats where calculated and cached.

     */

    public $timemodified;

    /**

     * Count of attempts selected by $this->whichattempts

     *

     * @return int

     */

    public function s() {

        return $this->get_field('count');

    }

    /**

     * Average grade for the attempts selected by $this->whichattempts

     *

     * @return float

     */

    public function avg() {

        return $this->get_field('avg');

    }

    /**

     * Get the right field name to fetch a stat for these attempts that is calculated for more than one $whichattempts (count or

     * avg).

     *

     * @param string $field name of field

     * @return int|float

     */

    protected function get_field($field) {

        $fieldname = calculator::using_attempts_string_id($this->whichattempts).$field;

        return $this->{$fieldname};

    }

    /**

     * @param $course

     * @param $cm

     * @param $quiz

     * @return array to display in table or spreadsheet.

     */

    public function get_formatted_quiz_info_data($course, $cm, $quiz) {

        // You can edit this array to control which statistics are displayed.

        $todisplay = ['firstattemptscount' => 'number',

                           'allattemptscount' => 'number',

                           'firstattemptsavg' => 'summarks_as_percentage',

                           'allattemptsavg' => 'summarks_as_percentage',

                           'lastattemptsavg' => 'summarks_as_percentage',

                           'highestattemptsavg' => 'summarks_as_percentage',

                           'median' => 'summarks_as_percentage',

                           'standarddeviation' => 'summarks_as_percentage',

                           'skewness' => 'number_format',

                           'kurtosis' => 'number_format',

                           'cic' => 'number_format_percent',

                           'errorratio' => 'number_format_percent',

                           'standarderror' => 'summarks_as_percentage'];

        // General information about the quiz.

        $quizinfo = [];

        $quizinfo[get_string('quizname', 'quiz_statistics')] = format_string($quiz->name);

        $quizinfo[get_string('coursename', 'quiz_statistics')] = format_string($course->fullname);

        if ($cm->idnumber) {

            $quizinfo[get_string('idnumbermod')] = $cm->idnumber;

        }

        if ($quiz->timeopen) {

            $quizinfo[get_string('quizopen', 'quiz')] = userdate($quiz->timeopen);

        }

        if ($quiz->timeclose) {

            $quizinfo[get_string('quizclose', 'quiz')] = userdate($quiz->timeclose);

        }

        if ($quiz->timeopen && $quiz->timeclose) {

            $quizinfo[get_string('duration', 'quiz_statistics')] =

                format_time($quiz->timeclose - $quiz->timeopen);

        }

        // The statistics.

        foreach ($todisplay as $property => $format) {

            if (!isset($this->$property) || !$format) {

                continue;

            }

            $value = $this->$property;

            switch ($format) {

                case 'summarks_as_percentage':

                    $formattedvalue = quiz_report_scale_summarks_as_percentage($value, $quiz);

                    break;

                case 'number_format_percent':

                    $formattedvalue = quiz_format_grade($quiz, $value) . '%';

                    break;

                case 'number_format':

                    // 2 extra decimal places, since not a percentage,

                    // and we want the same number of sig figs.

                    $formattedvalue = format_float($value, $quiz->decimalpoints + 2);

                    break;

                case 'number':

                    $formattedvalue = $value + 0;

                    break;

                default:

                    $formattedvalue = $value;

            }

            $quizinfo[get_string($property, 'quiz_statistics',

                                 calculator::using_attempts_lang_string($this->whichattempts))] = $formattedvalue;

        }

        return $quizinfo;

    }

    /**

     * @var array of names of properties of this class that are cached in db record.

     */

    protected $fieldsindb = ['whichattempts', 'firstattemptscount', 'allattemptscount', 'firstattemptsavg', 'allattemptsavg',

                                    'lastattemptscount', 'highestattemptscount', 'lastattemptsavg', 'highestattemptsavg',

                                    'median', 'standarddeviation', 'skewness',

                                    'kurtosis', 'cic', 'errorratio', 'standarderror'];

    /**

     * Cache the stats contained in this class.

     *

     * @param $qubaids \qubaid_condition

     */

    public function cache($qubaids) {

        global $DB;

        $toinsert = new \stdClass();

        foreach ($this->fieldsindb as $field) {

            $toinsert->{$field} = $this->{$field};

        }

        $toinsert->hashcode = $qubaids->get_hash_code();

        $toinsert->timemodified = time();

        // Fix up some dodgy data.

        if (isset($toinsert->errorratio) && is_nan($toinsert->errorratio)) {

            $toinsert->errorratio = null;

        }

        if (isset($toinsert->standarderror) && is_nan($toinsert->standarderror)) {

            $toinsert->standarderror = null;

        }

        // Delete older statistics before we save the new ones.

        $transaction = $DB->start_delegated_transaction();

        $DB->delete_records('quiz_statistics', ['hashcode' => $qubaids->get_hash_code()]);

        // Store the data.

        $DB->insert_record('quiz_statistics', $toinsert);

        $transaction->allow_commit();

    }

    /**

     * Given a record from 'quiz_statistics' table load the data into the properties of this class.

     *

     * @param $record \stdClass from db.

     */

    public function populate_from_record($record) {

        foreach ($this->fieldsindb as $field) {

            $this->$field = $record->$field;

        }

        $this->timemodified = $record->timemodified;

    }

}