/**
* Finds the module id from a resource instance, which is needed for the "get_cm($moduleid)" function, to get module's name.
* For that, uses the courses instances information, retrieved using "get_fast_modinfo($courseid)" function.
*
* @param array $instances Key is resource type name, and value is an array of each instance of the course of that type.
* @param int $resourceid The resource we are finding the moduleid of.
* @param int $courseid The course the module belongs to.
* @return int Module id.
*/
public static function get_resource_moduleid($instances, $resourceid, $courseid)
{
$db = new database_helper();
foreach ($instances as $instancetype => $typeinstances) {
$typeinstancesids = array_keys($typeinstances);
if (in_array($resourceid, $typeinstancesids)) {
$typeid = $db->get_module_type_id_by_name($instancetype);
$moduleid = $db->get_module_id($courseid, $resourceid, $typeid);
break;
}
}
return $moduleid;
}
/**
* Given the data of the historic users and the current ones, creates a matrix of association coefficients, with the
* current users as rows, and the historic user as columns.
*
* @see cosine_similarity($vector1, $vector2).
* @param array $currentdata A 2D array.
* @param array $historicdata A 2D array.
* @param \text_progress_trace $trace Text output trace.
* @return array The association matrix; empty if no association could be made.
*/
public function create_associations_matrix($currentdata, $historicdata, $trace)
{
$db = new database_helper();
$trace->output("[mycourse " . date('d/m/Y H:i:s') . "]: Starting creation of associations matrix.");
$trace->output("[mycourse " . date('d/m/Y H:i:s') . "]: Transforming receiving data to get a matrix of users x resources. " . " with the views as values.");
$currenttransformeddata = $this->matrix->transform_queried_data($currentdata);
$historictransformeddata = $this->matrix->transform_queried_data($historicdata);
$trace->output('[mycourse ' . date('d/m/Y H:i:s') . ']: Both historic and current data have been transformed.');
$currentusers = array_keys($currenttransformeddata);
$historicusers = array_keys($historictransformeddata);
$matrix = array();
foreach ($currentusers as $currentuser) {
$trace->output('[mycourse ' . date('d/m/Y H:i:s') . "]: Starting calculating associations for current user " . "{$currentuser}.");
$currentviewsvector = $currenttransformeddata[$currentuser];
$similarities = null;
foreach ($historicusers as $historicuser) {
$historicviewsvector = $historictransformeddata[$historicuser];
$trace->output('[mycourse ' . date('d/m/Y H:i:s') . "]: Starting calculating cosine similarity between a vector " . "of " . count($currentviewsvector) . " elements with a vector of " . count($historicviewsvector) . " elements.");
$similarity = $this->cosine_similarity($currentviewsvector, $historicviewsvector);
$trace->output('[mycourse ' . date('d/m/Y H:i:s') . ']: Cosine similarity between those vectors has been ' . 'calculated.');
$similarity = round($similarity, 4);
$similarities[$historicuser] = $similarity;
$db->insert_similarity($currentuser, $historicuser, $similarity, $this->currentweek);
}
$matrix[$currentuser] = $similarities;
$trace->output('[mycourse ' . date('d/m/Y H:i:s') . "]: Similarities for current user {$currentuser} have been " . "calculated.");
}
return $matrix;
}
/**
* Performs the data importation from Moodle core tables (courses, enrolled users, logs). This importation is done only if
* database_helper->has_data_to_be_imported() returns true.
*
* @param int $courseid The current course id for which the data has to be imported.
*/
protected function import_data($courseid)
{
$courseyear = $this->db->get_course_start_week_and_year($courseid)['year'];
$previouscourses = $this->db->find_course_previous_teaching_ids_core_tables($courseid, $courseyear);
foreach ($previouscourses as $previouscourse) {
$this->db->dump_previous_core_info_to_historic_tables($previouscourse);
}
$previouscourses = $this->db->find_course_previous_teachings_ids_historic_tables($courseid, $courseyear);
$this->db->insert_courses_associations($courseid, $previouscourses);
}
/**
* Initializes the course, when is the first instance of the block, looking if it is personalizable or not, and
* saving this in database.
*
* Currently, the students are being selected independently the course is personalizable or not, because maybe later
* a csv importation is made, and like this there's no need to select students later.
*
* @param int $courseid The course where the first instance of this block has been loaded in.
* @param int $courseyear The start year of the course.
*/
private function initialize_course($courseid, $courseyear)
{
$this->recommendator->select_students($courseid, $courseyear);
$personalizable = course_filter::is_course_personalizable($courseid, $courseyear);
if ($personalizable) {
$this->db->insert_course_selection($courseid, $courseyear, 1);
} else {
$this->db->insert_course_selection($courseid, $courseyear, 0);
}
}
/**
* Given the course identificator, selects, randomly, 50% of the students enrolled in the course,
* who will be the ones receiving the personalized recommendations.
* "array_rand" function returns the randomly selected keys, not values, so, we have to construct
* manually the array with random users.
*
* @param int $courseid The course to select students from.
* @param int $year The year the given course belongs to.
*/
public function select_students($courseid, $year)
{
$coursestudents = $this->db->get_students_from_course($courseid);
$count = count($coursestudents);
$selectedstudentsindexes = array_rand($coursestudents, $count / 2);
$selectedstudents = array();
foreach ($selectedstudentsindexes as $selectedindex) {
$selectedstudent = $coursestudents[$selectedindex];
array_push($selectedstudents, $selectedstudent);
}
$this->db->insert_selections($selectedstudents, $courseid, $year);
}
/**
* Imports the log views defined in the csv file, iterating each row. This is made under the transaction initiated in
* import_data function.
*
* @param object $logsfile Course csv file.
* @param object $formdata Submitted form data, needed to load the csv.
* @param int $courseid Generated course id in this transaction.
* @param \block_mycourse_recommendations\database_helper $db Database handler object, passed as argument to instance it
* again.
*/
public static function import_logs($logsfile, $formdata, $courseid, $db)
{
$iid = \csv_import_reader::get_new_iid('logsfile');
$csvreader = new \csv_import_reader($iid, 'logsfile');
$csvreader->load_csv_content($logsfile, $formdata->encoding, $formdata->delimiter_name);
$csvreader->init();
$fields = $csvreader->get_columns();
while ($fields) {
$userid = $fields[0];
$resourcename = $fields[1];
$resourcetype = $fields[2];
$resourceid = $fields[3];
$views = $fields[4];
$timecreated = $fields[5];
$db->insert_historic_logs($userid, $courseid, $resourcename, $resourcetype, $resourceid, $views, $timecreated);
self::$lastinsertedlogs++;
$fields = $csvreader->next();
}
$csvreader->close();
}
/**
* Determines if the course has had the minimum number of students in previous teachings.
* First, looks into Moodle core tables for existing previous students. If it doesn't find any, it tries luck in
* plugin's historic table. If it doesn't found neither here, means that the course has not previous students.
*
* @param int $courseid The course to determine if meets the minimum students.
* @param int $currentyear The year of the given current course.
* @param \block_mycourse_recommendations\database_helper $db The object with deals with database.
* @return boolean If the given course has the minimum students or not.
*/
public static function meets_minimum_previous_students($courseid, $currentyear, $db)
{
$previousstudents = $db->get_previous_courses_students_number_core_tables($courseid, $currentyear);
$minimum = false;
if ($previousstudents >= self::MINIMUM_PREVIOUS_STUDENTS) {
$minimum = true;
}
if (!$minimum) {
$previousstudents = $db->get_previous_courses_resources_number_historic_tables($courseid, $currentyear);
if ($previousstudents >= self::MINIMUM_PREVIOUS_STUDENTS) {
$minimum = true;
}
}
return $minimum;
}