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<?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/>.
/**
* Moodle course analysable
*
* @package core_analytics
* @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace core_analytics;
defined('MOODLE_INTERNAL') || die();
require_once($CFG->dirroot . '/course/lib.php');
require_once($CFG->dirroot . '/lib/gradelib.php');
require_once($CFG->dirroot . '/lib/enrollib.php');
/**
* Moodle course analysable
*
* @package core_analytics
* @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class course implements \core_analytics\analysable {
/**
* @var bool Has this course data been already loaded.
*/
protected $loaded = false;
/**
* @var int $cachedid self::$cachedinstance analysable id.
*/
protected static $cachedid = 0;
/**
* @var \core_analytics\course $cachedinstance
*/
protected static $cachedinstance = null;
/**
* Course object
*
* @var \stdClass
*/
protected $course = null;
/**
* The course context.
*
* @var \context_course
*/
protected $coursecontext = null;
/**
* The course activities organized by activity type.
*
* @var array
*/
protected $courseactivities = array();
/**
* Course start time.
*
* @var int
*/
protected $starttime = null;
/**
* Has the course already started?
*
* @var bool
*/
protected $started = null;
/**
* Course end time.
*
* @var int
*/
protected $endtime = null;
/**
* Is the course finished?
*
* @var bool
*/
protected $finished = null;
/**
* Course students ids.
*
* @var int[]
*/
protected $studentids = [];
/**
* Course teachers ids
*
* @var int[]
*/
protected $teacherids = [];
/**
* Cached copy of the total number of logs in the course.
*
* @var int
*/
protected $ntotallogs = null;
/**
* Course manager constructor.
*
* Use self::instance() instead to get cached copies of the course. Instances obtained
* through this constructor will not be cached.
*
* @param int|\stdClass $course Course id or mdl_course record
* @param \context|null $context
* @return void
*/
public function __construct($course, ?\context $context = null) {
if (is_scalar($course)) {
$this->course = new \stdClass();
$this->course->id = $course;
} else {
$this->course = $course;
}
if (!is_null($context)) {
$this->coursecontext = $context;
}
}
/**
* Returns an analytics course instance.
*
* Lazy load of course data, students and teachers.
*
* @param int|\stdClass $course Course object or course id
* @param \context|null $context
* @return \core_analytics\course
*/
public static function instance($course, ?\context $context = null) {
$courseid = $course;
if (!is_scalar($courseid)) {
$courseid = $course->id;
}
if (self::$cachedid === $courseid) {
return self::$cachedinstance;
}
$cachedinstance = new \core_analytics\course($course, $context);
self::$cachedinstance = $cachedinstance;
self::$cachedid = (int)$courseid;
return self::$cachedinstance;
}
/**
* get_id
*
* @return int
*/
public function get_id() {
return $this->course->id;
}
/**
* Loads the analytics course object.
*
* @return void
*/
protected function load() {
// The instance constructor could be already loaded with the full course object. Using shortname
// because it is a required course field.
if (empty($this->course->shortname)) {
$this->course = get_course($this->course->id);
}
$this->coursecontext = $this->get_context();
$this->now = time();
// Get the course users, including users assigned to student and teacher roles at an higher context.
$cache = \cache::make_from_params(\cache_store::MODE_REQUEST, 'core_analytics', 'rolearchetypes');
// Flag the instance as loaded.
$this->loaded = true;
if (!$studentroles = $cache->get('student')) {
$studentroles = array_keys(get_archetype_roles('student'));
$cache->set('student', $studentroles);
}
$this->studentids = $this->get_user_ids($studentroles);
if (!$teacherroles = $cache->get('teacher')) {
$teacherroles = array_keys(get_archetype_roles('editingteacher') + get_archetype_roles('teacher'));
$cache->set('teacher', $teacherroles);
}
$this->teacherids = $this->get_user_ids($teacherroles);
}
/**
* The course short name
*
* @return string
*/
public function get_name() {
return format_string($this->get_course_data()->shortname, true, array('context' => $this->get_context()));
}
/**
* get_context
*
* @return \context
*/
public function get_context() {
if ($this->coursecontext === null) {
$this->coursecontext = \context_course::instance($this->course->id);
}
return $this->coursecontext;
}
/**
* Get the course start timestamp.
*
* @return int Timestamp or 0 if has not started yet.
*/
public function get_start() {
if ($this->starttime !== null) {
return $this->starttime;
}
// The field always exist but may have no valid if the course is created through a sync process.
if (!empty($this->get_course_data()->startdate)) {
$this->starttime = (int)$this->get_course_data()->startdate;
} else {
$this->starttime = 0;
}
return $this->starttime;
}
/**
* Guesses the start of the course based on students' activity and enrolment start dates.
*
* @return int
*/
public function guess_start() {
global $DB;
if (!$this->get_total_logs()) {
// Can't guess.
return 0;
}
if (!$logstore = \core_analytics\manager::get_analytics_logstore()) {
return 0;
}
// We first try to find current course student logs.
$firstlogs = array();
foreach ($this->get_students() as $studentid) {
// Grrr, we are limited by logging API, we could do this easily with a
// select min(timecreated) from xx where courseid = yy group by userid.
// Filters based on the premise that more than 90% of people will be using
// standard logstore, which contains a userid, contextlevel, contextinstanceid index.
$select = "userid = :userid AND contextlevel = :contextlevel AND contextinstanceid = :contextinstanceid";
$params = array('userid' => $studentid, 'contextlevel' => CONTEXT_COURSE, 'contextinstanceid' => $this->get_id());
$events = $logstore->get_events_select($select, $params, 'timecreated ASC', 0, 1);
if ($events) {
$event = reset($events);
$firstlogs[] = $event->timecreated;
}
}
if (empty($firstlogs)) {
// Can't guess if no student accesses.
return 0;
}
sort($firstlogs);
$firstlogsmedian = $this->median($firstlogs);
$studentenrolments = enrol_get_course_users($this->get_id(), $this->get_students());
if (empty($studentenrolments)) {
return 0;
}
$enrolstart = array();
foreach ($studentenrolments as $studentenrolment) {
$enrolstart[] = ($studentenrolment->uetimestart) ? $studentenrolment->uetimestart : $studentenrolment->uetimecreated;
}
sort($enrolstart);
$enrolstartmedian = $this->median($enrolstart);
return intval(($enrolstartmedian + $firstlogsmedian) / 2);
}
/**
* Get the course end timestamp.
*
* @return int Timestamp or 0 if time end was not set.
*/
public function get_end() {
global $DB;
if ($this->endtime !== null) {
return $this->endtime;
}
// The enddate field is only available from Moodle 3.2 (MDL-22078).
if (!empty($this->get_course_data()->enddate)) {
$this->endtime = (int)$this->get_course_data()->enddate;
return $this->endtime;
}
return 0;
}
/**
* Get the course end timestamp.
*
* @return int Timestamp, \core_analytics\analysable::MAX_TIME if we don't know but ongoing and 0 if we can not work it out.
*/
public function guess_end() {
global $DB;
if ($this->get_total_logs() === 0) {
// No way to guess if there are no logs.
$this->endtime = 0;
return $this->endtime;
}
list($filterselect, $filterparams) = $this->course_students_query_filter('ula');
// Consider the course open if there are still student accesses.
$monthsago = time() - (WEEKSECS * 4 * 2);
$select = $filterselect . ' AND timeaccess > :timeaccess';
$params = $filterparams + array('timeaccess' => $monthsago);
$sql = "SELECT DISTINCT timeaccess FROM {user_lastaccess} ula
JOIN {enrol} e ON e.courseid = ula.courseid
JOIN {user_enrolments} ue ON e.id = ue.enrolid AND ue.userid = ula.userid
WHERE $select";
if ($records = $DB->get_records_sql($sql, $params)) {
return 0;
}
$sql = "SELECT DISTINCT timeaccess FROM {user_lastaccess} ula
JOIN {enrol} e ON e.courseid = ula.courseid
JOIN {user_enrolments} ue ON e.id = ue.enrolid AND ue.userid = ula.userid
WHERE $filterselect AND ula.timeaccess != 0
ORDER BY timeaccess DESC";
$studentlastaccesses = $DB->get_fieldset_sql($sql, $filterparams);
if (empty($studentlastaccesses)) {
return 0;
}
sort($studentlastaccesses);
return $this->median($studentlastaccesses);
}
/**
* Returns a course plain object.
*
* @return \stdClass
*/
public function get_course_data() {
if (!$this->loaded) {
$this->load();
}
return $this->course;
}
/**
* Has the course started?
*
* @return bool
*/
public function was_started() {
if ($this->started === null) {
if ($this->get_start() === 0 || $this->now < $this->get_start()) {
// Not yet started.
$this->started = false;
} else {
$this->started = true;
}
}
return $this->started;
}
/**
* Has the course finished?
*
* @return bool
*/
public function is_finished() {
if ($this->finished === null) {
$endtime = $this->get_end();
if ($endtime === 0 || $this->now < $endtime) {
// It is not yet finished or no idea when it finishes.
$this->finished = false;
} else {
$this->finished = true;
}
}
return $this->finished;
}
/**
* Returns a list of user ids matching the specified roles in this course.
*
* @param array $roleids
* @return array
*/
public function get_user_ids($roleids) {
// We need to index by ra.id as a user may have more than 1 $roles role.
$records = get_role_users($roleids, $this->get_context(), true, 'ra.id, u.id AS userid, r.id AS roleid', 'ra.id ASC');
// If a user have more than 1 $roles role array_combine will discard the duplicate.
$callable = array($this, 'filter_user_id');
$userids = array_values(array_map($callable, $records));
return array_combine($userids, $userids);
}
/**
* Returns the course students.
*
* @return int[]
*/
public function get_students() {
if (!$this->loaded) {
$this->load();
}
return $this->studentids;
}
/**
* Returns the total number of student logs in the course
*
* @return int
*/
public function get_total_logs() {
global $DB;
// No logs if no students.
if (empty($this->get_students())) {
return 0;
}
if ($this->ntotallogs === null) {
list($filterselect, $filterparams) = $this->course_students_query_filter();
if (!$logstore = \core_analytics\manager::get_analytics_logstore()) {
$this->ntotallogs = 0;
} else {
$this->ntotallogs = $logstore->get_events_select_count($filterselect, $filterparams);
}
}
return $this->ntotallogs;
}
/**
* Returns all the activities of the provided type the course has.
*
* @param string $activitytype
* @return array
*/
public function get_all_activities($activitytype) {
// Using is set because we set it to false if there are no activities.
if (!isset($this->courseactivities[$activitytype])) {
$modinfo = get_fast_modinfo($this->get_course_data(), -1);
$instances = $modinfo->get_instances_of($activitytype);
if ($instances) {
$this->courseactivities[$activitytype] = array();
foreach ($instances as $instance) {
// By context.
$this->courseactivities[$activitytype][$instance->context->id] = $instance;
}
} else {
$this->courseactivities[$activitytype] = false;
}
}
return $this->courseactivities[$activitytype];
}
/**
* Returns the course students grades.
*
* @param array $courseactivities
* @return array
*/
public function get_student_grades($courseactivities) {
if (empty($courseactivities)) {
return array();
}
$grades = array();
foreach ($courseactivities as $contextid => $instance) {
$gradesinfo = grade_get_grades($this->course->id, 'mod', $instance->modname, $instance->instance, $this->studentids);
// Sort them by activity context and user.
if ($gradesinfo && $gradesinfo->items) {
foreach ($gradesinfo->items as $gradeitem) {
foreach ($gradeitem->grades as $userid => $grade) {
if (empty($grades[$contextid][$userid])) {
// Initialise it as array because a single activity can have multiple grade items (e.g. workshop).
$grades[$contextid][$userid] = array();
}
$grades[$contextid][$userid][$gradeitem->id] = $grade;
}
}
}
}
return $grades;
}
/**
* Used by get_user_ids to extract the user id.
*
* @param \stdClass $record
* @return int The user id.
*/
protected function filter_user_id($record) {
return $record->userid;
}
/**
* Returns the average time between 2 timestamps.
*
* @param int $start
* @param int $end
* @return array [starttime, averagetime, endtime]
*/
protected function update_loop_times($start, $end) {
$avg = intval(($start + $end) / 2);
return array($start, $avg, $end);
}
/**
* Returns the query and params used to filter the logstore by this course students.
*
* @param string $prefix
* @return array
*/
protected function course_students_query_filter($prefix = false) {
global $DB;
if ($prefix) {
$prefix = $prefix . '.';
}
// Check the amount of student logs in the 4 previous weeks.
list($studentssql, $studentsparams) = $DB->get_in_or_equal($this->get_students(), SQL_PARAMS_NAMED);
$filterselect = $prefix . 'courseid = :courseid AND ' . $prefix . 'userid ' . $studentssql;
$filterparams = array('courseid' => $this->course->id) + $studentsparams;
return array($filterselect, $filterparams);
}
/**
* Calculate median
*
* Keys are ignored.
*
* @param int[]|float[] $values Sorted array of values
* @return int
*/
protected function median($values) {
$count = count($values);
if ($count === 1) {
return reset($values);
}
$middlevalue = (int)floor(($count - 1) / 2);
if ($count % 2) {
// Odd number, middle is the median.
$median = $values[$middlevalue];
} else {
// Even number, calculate avg of 2 medians.
$low = $values[$middlevalue];
$high = $values[$middlevalue + 1];
$median = (($low + $high) / 2);
}
return intval($median);
}
}