$promotion = new Promotion();
$id = intval($_GET['id']);
if (isset($_POST['form_sent']) && $_POST['form_sent']) {
    $form_sent = $_POST['form_sent'];
    $session_in_promotion_posted = $_POST['session_in_promotion_name'];
    if (!is_array($session_in_promotion_posted)) {
        $session_in_promotion_posted = array();
    }
    if ($form_sent == 1) {
        // Added a parameter to send emails when registering a user
        SessionManager::suscribe_sessions_to_promotion($id, $session_in_promotion_posted);
        header('Location: promotions.php');
        exit;
    }
}
$promotion_data = $promotion->get($id);
$session_list = SessionManager::get_sessions_list(array(), array('name'));
$session_not_in_promotion = $session_in_promotion = array();
if (!empty($session_list)) {
    foreach ($session_list as $session) {
        $promotion_id = $session['promotion_id'];
        if (isset($promotion_id) && !empty($promotion_id)) {
            if ($promotion_id == $id) {
                $session_in_promotion[$session['id']] = $session['name'];
            } else {
                $session_not_in_promotion[$session['id']] = $session['name'];
            }
        } else {
            $session_not_in_promotion[$session['id']] = $session['name'];
        }
    }