/**
* Method to generate list of friends up to _maximumCircleRadius'th order (_maximumCircleRadius'th circle) for each user,
* and save it to the database
*
* @param MySQLi Database handler
*
* @return null
*/
public static function prepareFriendList($db)
{
//read list of connections from the DB
$result = $db->query("SELECT id, connect_from, connect_to FROM connections ORDER BY connect_from ASC");
while ($row = $result->fetch_object()) {
$connections[] = $row;
}
//start: prepare list of friends of the 1st order (1st circle)
$friends = array();
foreach ($connections as $c) {
$friends[1][$c->connect_from][] = $c->connect_to;
}
SixDegrees::_prepareCircles($friends);
//end: prepare list of friends of the 1st order (1st circle)
//start: for each user, convert array of friends of different orders into a list
foreach ($friends as $circle => $users) {
foreach ($users as $id_user => $f) {
$f = array_unique($f);
sort($f);
$friends[$circle][$id_user] = implode($f, ',');
}
}
//end: for each user, convert array of friends of different orders into a list
foreach ($friends[1] as $id_user => $v) {
//for each user, save their circles to the database
if (!empty($v)) {
$t = $db->prepare("INSERT INTO friends SET id_user = '******',\n\t\t\tfriends1 = '" . $friends[1][$id_user] . "', \n\t\t\tfriends2 = '" . $friends[2][$id_user] . "',\n\t\t\tfriends3 = '" . $friends[3][$id_user] . "',\n\t\t\tfriends4 = '" . $friends[4][$id_user] . "' \n\t\t\tON DUPLICATE KEY UPDATE \n\t\t\tfriends1 = '" . $friends[1][$id_user] . "', \n\t\t\tfriends2 = '" . $friends[2][$id_user] . "',\n\t\t\tfriends3 = '" . $friends[3][$id_user] . "',\n\t\t\tfriends4 = '" . $friends[4][$id_user] . "' \n\t\t\t");
$t->execute();
}
}
}
