lib/classes/analytics/target/course_gradetopass.php

   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  * Getting the minimum grade to pass target.
  19  *
  20  * @package   core
  21  * @copyright 2019 Victor Deniz <victor@moodle.com>
  22  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 namespace core\analytics\target;
  26
  27 defined('MOODLE_INTERNAL') || die();
  28
  29
  30 /**
  31  * Getting the minimum grade to pass target.
  32  *
  33  * @package   core
  34  * @copyright 2019 Victor Deniz <victor@moodle.com>
  35  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  36  */
  37 class course_gradetopass extends \core\analytics\target\course_enrolments {
  38
  39     /**
  40      * Courses grades to pass.
  41      * @var mixed[]
  42      */
  43     protected $coursesgradetopass = array();
  44
  45     /**
  46      * Courses grades.
  47      * @var mixed[]
  48      */
  49     protected $coursesgrades = array();
  50
  51     /**
  52      * Returns the grade to pass a course.
  53      *
  54      * Save the value in $coursesgradetopass array to prevent new accesses to the database.
  55      *
  56      * @param int $courseid The course id.
  57      * @return array The courseitem id and the required grade to pass the course.
  58      */
  59     protected function get_course_gradetopass($courseid) {
  60         if (!isset($this->coursesgradetopass[$courseid])) {
  61             // Get course grade_item.
  62             $courseitem = \grade_item::fetch_course_item($courseid);
  63
  64             $ci = array();
  65             $ci['courseitemid'] = $courseitem->id;
  66
  67             if ($courseitem->gradetype == GRADE_TYPE_VALUE && grade_floats_different($courseitem->gradepass, 0.0)) {
  68                 $ci['gradetopass'] = $courseitem->gradepass;
  69             } else {
  70                 $ci['gradetopass'] = null;
  71             }
  72             $this->coursesgradetopass[$courseid] = $ci;
  73         }
  74
  75         return $this->coursesgradetopass[$courseid];
  76     }
  77
  78     /**
  79      * Returns the grade of a user in a course.
  80      *
  81      * Saves the grades of all course users in $coursesgrades array to prevent new accesses to the database.
  82      *
  83      * @param  int $courseitemid The course item id.
  84      * @param  int $userid the user whose grade is requested.
  85      * @return array The courseitem id and the required grade to pass the course.
  86      */
  87     protected function get_user_grade($courseitemid, $userid) {
  88         // If the user grade for this course is not available, get all the grades for the course.
  89         if (!isset($this->coursesgrades[$courseitemid])) {
  90             // Ony a course is cached to avoid high memory usage.
  91             unset($this->coursesgrades);
  92             $gg = new \grade_grade(null, false);
  93             $usersgrades = $gg->fetch_all(array('itemid' => $courseitemid));
  94
  95             if ($usersgrades) {
  96                 foreach ($usersgrades as $ug) {
  97                     $this->coursesgrades[$courseitemid][$ug->userid] = $ug->finalgrade;
  98                 }
  99             }
 100         }
 101
 102         if (!isset($this->coursesgrades[$courseitemid][$userid])) {
 103             $this->coursesgrades[$courseitemid][$userid] = null;
 104         }
 105
 106         return $this->coursesgrades[$courseitemid][$userid];
 107     }
 108
 109     /**
 110      * Returns the name.
 111      *
 112      * If there is a corresponding '_help' string this will be shown as well.
 113      *
 114      * @return \lang_string
 115      */
 116     public static function get_name() : \lang_string {
 117         return new \lang_string('target:coursegradetopass');
 118     }
 119
 120     /**
 121      * Returns descriptions for each of the values the target calculation can return.
 122      *
 123      * @return string[]
 124      */
 125     protected static function classes_description() {
 126         return array(
 127             get_string('targetlabelstudentgradetopassno'),
 128             get_string('targetlabelstudentgradetopassyes')
 129         );
 130     }
 131
 132     /**
 133      * Discards courses that are not yet ready to be used for training or prediction.
 134      *
 135      * Only courses with "value" grade type and grade to pass set are valid.
 136      *
 137      * @param \core_analytics\analysable $course
 138      * @param bool $fortraining
 139      * @return true|string
 140      */
 141     public function is_valid_analysable(\core_analytics\analysable $course, $fortraining = true) {
 142         $isvalid = parent::is_valid_analysable($course, $fortraining);
 143
 144         if (is_string($isvalid)) {
 145             return $isvalid;
 146         }
 147
 148         $courseitem = $this->get_course_gradetopass ($course->get_id());
 149         if (is_null($courseitem['gradetopass'])) {
 150             return get_string('gradetopassnotset', 'course');
 151         }
 152
 153         return true;
 154     }
 155
 156     /**
 157      * The user's grade in the course sets the target value.
 158      *
 159      * @param int $sampleid
 160      * @param \core_analytics\analysable $course
 161      * @param int $starttime
 162      * @param int $endtime
 163      * @return float 0 -> course grade to pass achieved, 1 -> course grade to pass not achieved
 164      */
 165     protected function calculate_sample($sampleid, \core_analytics\analysable $course, $starttime = false, $endtime = false) {
 166
 167         $userenrol = $this->retrieve('user_enrolments', $sampleid);
 168
 169         // Get course grade to pass.
 170         $courseitem = $this->get_course_gradetopass($course->get_id());
 171
 172         // Get the user grade.
 173         $usergrade = $this->get_user_grade($courseitem['courseitemid'], $userenrol->userid);
 174
 175         if ($usergrade >= $courseitem['gradetopass']) {
 176             return 0;
 177         }
 178
 179         return 1;
 180     }
 181 }