RegistrationModel::sendVerificationEmail PHP Method

    public static function sendVerificationEmail($user_id, $user_email, $user_activation_hash)
    {
        $body = Config::get('EMAIL_VERIFICATION_CONTENT') . Config::get('URL') . Config::get('EMAIL_VERIFICATION_URL') . '/' . urlencode($user_id) . '/' . urlencode($user_activation_hash);
        $mail = new Mail();
        $mail_sent = $mail->sendMail($user_email, Config::get('EMAIL_VERIFICATION_FROM_EMAIL'), Config::get('EMAIL_VERIFICATION_FROM_NAME'), Config::get('EMAIL_VERIFICATION_SUBJECT'), $body);
        if ($mail_sent) {
            Session::add('feedback_positive', Text::get('FEEDBACK_VERIFICATION_MAIL_SENDING_SUCCESSFUL'));
            return true;
        } else {
            Session::add('feedback_negative', Text::get('FEEDBACK_VERIFICATION_MAIL_SENDING_ERROR') . $mail->getError());
            return false;
        }
    }

 /**
  * Handles the entire registration process for DEFAULT users (not for people who register with
  * 3rd party services, like facebook) and creates a new user in the database if everything is fine
  *
  * @return boolean Gives back the success status of the registration
  */
 public static function registerNewUser()
 {
     // TODO this could be written simpler and cleaner
     // clean the input
     $user_name = strip_tags(Request::post('user_name'));
     $user_email = strip_tags(Request::post('user_email'));
     $user_password_new = Request::post('user_password_new');
     $user_password_repeat = Request::post('user_password_repeat');
     // stop registration flow if registrationInputValidation() returns false (= anything breaks the input check rules)
     if (Config::get('RECAPTCHA_ENABLED')) {
         $validation_result = RegistrationModel::registrationInputValidation(Request::post('g-recaptcha-response'), $user_name, $user_password_new, $user_password_repeat, $user_email);
     } else {
         $validation_result = RegistrationModel::registrationInputValidation(Request::post('captcha'), $user_name, $user_password_new, $user_password_repeat, $user_email);
     }
     if (!$validation_result) {
         return false;
     }
     // crypt the password with the PHP 5.5's password_hash() function, results in a 60 character hash string.
     // @see php.net/manual/en/function.password-hash.php for more, especially for potential options
     $user_password_hash = password_hash($user_password_new, PASSWORD_DEFAULT);
     // check if username already exists
     if (UserModel::doesUsernameAlreadyExist($user_name)) {
         Session::add('feedback_negative', Text::get('FEEDBACK_USERNAME_ALREADY_TAKEN'));
         return false;
     }
     // check if email already exists
     if (UserModel::doesEmailAlreadyExist($user_email)) {
         Session::add('feedback_negative', Text::get('FEEDBACK_USER_EMAIL_ALREADY_TAKEN'));
         return false;
     }
     // generate random hash for email verification (40 char string)
     $user_activation_hash = sha1(uniqid(mt_rand(), true));
     // write user data to database
     if (!RegistrationModel::writeNewUserToDatabase($user_name, $user_password_hash, $user_email, time(), $user_activation_hash)) {
         Session::add('feedback_negative', Text::get('FEEDBACK_ACCOUNT_CREATION_FAILED'));
     }
     // get user_id of the user that has been created, to keep things clean we DON'T use lastInsertId() here
     $user_id = UserModel::getUserIdByUsername($user_name);
     if (!$user_id) {
         Session::add('feedback_negative', Text::get('FEEDBACK_UNKNOWN_ERROR'));
         return false;
     }
     // send verification email
     if (RegistrationModel::sendVerificationEmail($user_id, $user_email, $user_activation_hash)) {
         Session::add('feedback_positive', Text::get('FEEDBACK_ACCOUNT_SUCCESSFULLY_CREATED'));
         return true;
     }
     // if verification email sending failed: instantly delete the user
     RegistrationModel::rollbackRegistrationByUserId($user_id);
     Session::add('feedback_negative', Text::get('FEEDBACK_VERIFICATION_MAIL_SENDING_FAILED'));
     return false;
 }