Pop\Mail\Message::getMessageType PHP Method

    protected function getMessageType()
    {
        $type = null;
        $numAttach = count($this->mail->getAttachments());
        if ($numAttach > 0 && null === $this->html && null === $this->text) {
            $type = null;
        } else {
            if ($numAttach > 0 && null !== $this->html && null !== $this->text) {
                $type = self::TEXT_HTML_FILE;
            } else {
                if ($numAttach > 0 && null !== $this->html) {
                    $type = self::HTML_FILE;
                } else {
                    if ($numAttach > 0 && null !== $this->text) {
                        $type = self::TEXT_FILE;
                    } else {
                        if (null !== $this->html && null !== $this->text) {
                            $type = self::TEXT_HTML;
                        } else {
                            if (null !== $this->html) {
                                $type = self::HTML;
                            } else {
                                if (null !== $this->text) {
                                    $type = self::TEXT;
                                }
                            }
                        }
                    }
                }
            }
        }
        return $type;
    }