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/>.

/**

 * Drop out course target.

 *

 * @package   core_course

 * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}

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

 */

namespace core_course\analytics\target;

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

require_once($CFG->dirroot . '/course/lib.php');

require_once($CFG->dirroot . '/lib/gradelib.php');

require_once($CFG->dirroot . '/lib/completionlib.php');

require_once($CFG->dirroot . '/completion/completion_completion.php');

/**

 * Drop out course target.

 *

 * @package   core_course

 * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}

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

 */

class course_dropout extends 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:coursedropout', 'course');

    }

    /**

     * classes_description

     *

     * @return string[]

     */

    protected static function classes_description() {

        return array(

            get_string('targetlabelstudentdropoutno', 'course'),

            get_string('targetlabelstudentdropoutyes', 'course')

        );

    }

    /**

     * 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) {

        global $DB;

        $isvalid = parent::is_valid_analysable($course, $fortraining);

        if (is_string($isvalid)) {

            return $isvalid;

        }

        if ($fortraining) {

            // Not a valid target for training if there are not enough course accesses between the course start and end dates.

            $params = array('courseid' => $course->get_id(), 'anonymous' => 0, 'start' => $course->get_start(),

                'end' => $course->get_end());

            list($studentssql, $studentparams) = $DB->get_in_or_equal($this->students, SQL_PARAMS_NAMED);

            // Using anonymous to use the db index, not filtering by timecreated to speed it up.

            $select = 'courseid = :courseid AND anonymous = :anonymous AND timecreated > :start AND timecreated < :end ' .

                'AND userid ' . $studentssql;

            if (!$logstore = \core_analytics\manager::get_analytics_logstore()) {

                throw new \coding_exception('No available log stores');

            }

            $nlogs = $logstore->get_events_select_count($select, array_merge($params, $studentparams));

            // At least a minimum of students activity.

            $nstudents = count($this->students);

            if ($nlogs / $nstudents < 10) {

                return get_string('nocourseactivity', 'course');

            }

        }

        return true;

    }

    /**

     * calculate_sample

     *

     * The meaning of a drop out changes depending on the settings enabled in the course. Following these priorities order:

     * 1.- Course completion

     * 2.- No logs during the last quarter of the course

     *

     * @param int $sampleid

     * @param \core_analytics\analysable $course

     * @param int $starttime

     * @param int $endtime

     * @return float|null 0 -> not at risk, 1 -> at risk

     */

    protected function calculate_sample($sampleid, \core_analytics\analysable $course, $starttime = false, $endtime = false) {

        if (!$this->enrolment_active_during_analysis_time($sampleid, $starttime, $endtime)) {

            // We should not use this sample as the analysis results could be misleading.

            return null;

        }

        $userenrol = $this->retrieve('user_enrolments', $sampleid);

        // We use completion as a success metric only when it is enabled.

        $completion = new \completion_info($course->get_course_data());

        if ($completion->is_enabled() && $completion->has_criteria()) {

            $ccompletion = new \completion_completion(array('userid' => $userenrol->userid, 'course' => $course->get_id()));

            if ($ccompletion->is_complete()) {

                return 0;

            } else {

                return 1;

            }

        }

        if (!$logstore = \core_analytics\manager::get_analytics_logstore()) {

            throw new \coding_exception('No available log stores');

        }

        // No logs during the last quarter of the course.

        $courseduration = $course->get_end() - $course->get_start();

        $limit = intval($course->get_end() - ($courseduration / 4));

        $select = "courseid = :courseid AND userid = :userid AND timecreated > :limit";

        $params = array('userid' => $userenrol->userid, 'courseid' => $course->get_id(), 'limit' => $limit);

        $nlogs = $logstore->get_events_select_count($select, $params);

        if ($nlogs == 0) {

            return 1;

        }

        return 0;

    }

}