Jyxo\Mail\Parser::getHeaders PHP Method

    public function getHeaders(string $pid = null) : array
    {
        // Parses headers
        $rawHeaders = $this->getRawHeaders($pid);
        if (null === $pid) {
            $msgno = imap_msgno($this->connection, $this->uid);
            if (0 === $msgno) {
                throw new Parser\EmailNotExistException('Email does not exist');
            }
            $headerInfo = imap_headerinfo($this->connection, $msgno);
        } else {
            $headerInfo = imap_rfc822_parse_headers($rawHeaders);
        }
        // Adds a header that the IMAP extension does not support
        if (preg_match("~Disposition-Notification-To:(.+?)(?=\r?\n(?:\\S|\r?\n))~is", $rawHeaders, $matches)) {
            $addressList = imap_rfc822_parse_adrlist($matches[1], '');
            // {''} is used because of CS rules
            $headerInfo->{'disposition_notification_toaddress'} = substr(trim($matches[1]), 0, 1024);
            $headerInfo->{'disposition_notification_to'} = [$addressList[0]];
        }
        $headers = [];
        static $mimeHeaders = ['toaddress', 'ccaddress', 'bccaddress', 'fromaddress', 'reply_toaddress', 'senderaddress', 'return_pathaddress', 'subject', 'fetchfrom', 'fetchsubject', 'disposition_notification_toaddress'];
        foreach ($headerInfo as $key => $value) {
            if (!is_object($value) && !is_array($value)) {
                if (in_array($key, $mimeHeaders)) {
                    $headers[$key] = $this->decodeMimeHeader($value);
                } else {
                    $headers[$key] = $this->convertToUtf8((string) $value);
                }
            }
        }
        // Adds "udate" if missing
        if (!empty($headerInfo->udate)) {
            $headers['udate'] = $headerInfo->udate;
        } elseif (!empty($headerInfo->date)) {
            $headers['udate'] = strtotime($headerInfo->date);
        } else {
            $headers['udate'] = time();
        }
        // Parses references
        $headers['references'] = isset($headers['references']) ? explode('> <', trim($headers['references'], '<>')) : [];
        static $types = ['to', 'cc', 'bcc', 'from', 'reply_to', 'sender', 'return_path', 'disposition_notification_to'];
        for ($i = 0; $i < count($types); $i++) {
            $type = $types[$i];
            $headers[$type] = [];
            if (isset($headerInfo->{$type})) {
                foreach ($headerInfo->{$type} as $object) {
                    $newHeader = [];
                    foreach ($object as $attributeName => $attributeValue) {
                        if (!empty($attributeValue)) {
                            $newHeader[$attributeName] = 'personal' === $attributeName ? $this->decodeMimeHeader($attributeValue) : $this->convertToUtf8($attributeValue);
                        }
                    }
                    if (!empty($newHeader)) {
                        if (isset($newHeader['mailbox'], $newHeader['host'])) {
                            $newHeader['email'] = $newHeader['mailbox'] . '@' . $newHeader['host'];
                        } elseif (isset($newHeader['mailbox'])) {
                            $newHeader['email'] = $newHeader['mailbox'];
                        } else {
                            $newHeader['email'] = 'undisclosed-recipients';
                        }
                        $headers[$type][] = $newHeader;
                    }
                }
            }
        }
        // Adds X-headers
        if (preg_match_all("~(X(?:[\\-]\\w+)+):(.+?)(?=\r?\n(?:\\S|\r?\n))~is", $rawHeaders, $matches) > 0) {
            for ($i = 0; $i < count($matches[0]); $i++) {
                // Converts to the format used by imap_headerinfo()
                $key = str_replace('-', '_', strtolower($matches[1][$i]));
                // Removes line endings
                $value = strtr(trim($matches[2][$i]), ["\r" => '', "\n" => '', "\t" => ' ']);
                $headers[$key] = $value;
            }
        }
        return $headers;
    }