MDL-64636 analytics: new course_completion target

Added new target to predict which students are at risk of not meeting
the course completion criteria.

lib/classes/analytics/target/course_completion.php

@@ -0,0 +1,109 @@
+<?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/>.
+
+/**
+ * Course completion target.
+ *
+ * @package   core
+ * @copyright 2019 Victor Deniz <victor@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core\analytics\target;
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->dirroot . '/course/lib.php');
+require_once($CFG->dirroot . '/lib/completionlib.php');
+require_once($CFG->dirroot . '/completion/completion_completion.php');
+
+/**
+ * Course completion target.
+ *
+ * @package   core
+ * @copyright 2019 Victor Deniz <victor@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class course_completion extends \core\analytics\target\course_enrolments {
+
+    /**
+     * Returns the name.
+     *
+     * If there is a corresponding '_help' string this will be shown as well.
+     *
+     * @return \lang_string
+     */
+    public static function get_name() : \lang_string {
+        return new \lang_string('target:coursecompletion');
+    }
+
+    /**
+     * Returns descriptions for each of the values the target calculation can return.
+     *
+     * @return string[]
+     */
+    protected static function classes_description() {
+        return array(
+            get_string('targetlabelstudentcompletionno'),
+            get_string('targetlabelstudentcompletionyes')
+        );
+    }
+
+    /**
+     * Discards courses that are not yet ready to be used for training or prediction.
+     *
+     * @param \core_analytics\analysable $course
+     * @param bool $fortraining
+     * @return true|string
+     */
+    public function is_valid_analysable(\core_analytics\analysable $course, $fortraining = true) {
+        $isvalid = parent::is_valid_analysable($course, $fortraining);
+
+        if (is_string($isvalid)) {
+            return $isvalid;
+        }
+
+        // Not a valid target if completion is not enabled or there are not completion criteria defined.
+        $completion = new \completion_info($course->get_course_data());
+        if (!$completion->is_enabled() || !$completion->has_criteria()) {
+            return get_string('completionnotenabledforcourse', 'completion');
+        }
+
+        return true;
+    }
+
+    /**
+     * Course completion sets the target value.
+     *
+     * @param int $sampleid
+     * @param \core_analytics\analysable $course
+     * @param int $starttime
+     * @param int $endtime
+     * @return float 0 -> course not completed, 1 -> course completed
+     */
+    protected function calculate_sample($sampleid, \core_analytics\analysable $course, $starttime = false, $endtime = false) {
+
+        $userenrol = $this->retrieve('user_enrolments', $sampleid);
+
+        // We use completion as a success metric.
+        $ccompletion = new \completion_completion(array('userid' => $userenrol->userid, 'course' => $course->get_id()));
+        if ($ccompletion->is_complete()) {
+            return 0;
+        } else {
+            return 1;
+        }
+    }
+}