<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Plugin to check submitted notices with Mollom
 *
 * Mollom is a bayesian spam checker, wrapped into a webservice
 * This plugin is based on the Drupal Mollom Plugin
 *
 * @category  Plugin
 * @package   GNUsocial
 * @author    Brenda Wallace <brenda@cpan.org>
 * @copyright 2010 StatusNet, Inc.
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUsocial') || die();

define('MOLLOMPLUGIN_VERSION', '0.1');
define('MOLLOM_API_VERSION', '1.0');

define('MOLLOM_ANALYSIS_UNKNOWN', 0);
define('MOLLOM_ANALYSIS_HAM', 1);
define('MOLLOM_ANALYSIS_SPAM', 2);
define('MOLLOM_ANALYSIS_UNSURE', 3);

define('MOLLOM_MODE_DISABLED', 0);
define('MOLLOM_MODE_CAPTCHA', 1);
define('MOLLOM_MODE_ANALYSIS', 2);

define('MOLLOM_FALLBACK_BLOCK', 0);
define('MOLLOM_FALLBACK_ACCEPT', 1);

define('MOLLOM_ERROR', 1000);
define('MOLLOM_REFRESH', 1100);
define('MOLLOM_REDIRECT', 1200);

/**
 * Plugin to check submitted notices with Mollom
 *
 * Mollom is a bayesian spam filter provided by webservice.
 *
 * @category  Plugin
 * @package   GNUsocial
 * @author    Brenda Wallace <shiny@cpan.org>
 * @copyright 2010 StatusNet, Inc.
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 *
 * @see      Event
 */
class MollomPlugin extends Plugin
{
    public $public_key;
    public $private_key;
    public $servers = null;

    public function onStartNoticeSave($notice)
    {
        if ($this->public_key) {
            //Check spam
            $data = [
                'post_body'   => $notice->content,
                'author_name' => $profile->nickname,
                'author_url'  => $profile->homepage,
                'author_id'   => $profile->id,
                'author_ip'   => $this->getClientIp(),
            ];
            $response = $this->mollom('mollom.checkContent', $data);
            switch ($response['spam']) {
                case MOLLOM_ANALYSIS_SPAM:
                    // TRANS: Client exception thrown when notice content triggers the spam filter.
                    throw new ClientException(_m('Spam Detected.'), 400);
                case MOLLOM_ANALYSIS_UNSURE:
                    //if unsure, let through
                    break;
                case MOLLOM_ANALYSIS_HAM:
                    // all good! :-)
                    break;
            }
        }

        return true;
    }

    public function getClientIP()
    {
        if (isset($_SERVER) && array_key_exists('REQUEST_METHOD', $_SERVER)) {
            // Note: order matters here; use proxy-forwarded stuff first
            foreach (array('HTTP_X_FORWARDED_FOR', 'CLIENT-IP', 'REMOTE_ADDR') as $k) {
                if (isset($_SERVER[$k])) {
                    return $_SERVER[$k];
                }
            }
        }
        return '127.0.0.1';
    }

    /**
     * Call a remote procedure at the Mollom server.  This function will
     * automatically add the information required to authenticate against
     * Mollom.
     */
    public function mollom($method, $data = [])
    {
        if (!extension_loaded('xmlrpc')) {
            if (!dl('xmlrpc.so')) {
                common_log(LOG_ERR, "Can't pingback; xmlrpc extension not available.");
            }
        }

        // Construct the server URL:
        $public_key = $this->public_key;
        // Retrieve the list of Mollom servers from the database:
        $servers = $this->servers;

        if (is_null($servers)) {
            // Retrieve a list of valid Mollom servers from mollom.com:
            $servers = $this->xmlrpc('http://xmlrpc.mollom.com/'. MOLLOM_API_VERSION, 'mollom.getServerList', $this->authentication());

            // Store the list of servers in the database:
            // @todo variable_set('mollom_servers', $servers);
        }

        if (is_array($servers)) {
            // Send the request to the first server, if that fails, try the other servers in the list:
            foreach ($servers as $server) {
                $auth = $this->authentication();
                $data = array_merge($data, $auth);
                $result = $this->xmlrpc(
                    $server . '/' . MOLLOM_API_VERSION,
                    $method,
                    $data
                );

                // Debug output:
                if (array_key_exists('session_id', $data)) {
                    common_debug(
                        "called {$method} at server {$server} with session ID "
                        . "'{$data['session_id']}'"
                    );
                } else {
                    common_debug(
                        "called {$method} at server {$server} with no session ID"
                    );
                }

                if (!empty($errno = $this->xmlrpc_errno())) {
                    common_log(LOG_ERR, sprintf(
                        'Error @errno: %s - %s - %s - <pre>%s</pre>',
                        $this->xmlrpc_errno(),
                        $server,
                        $this->xmlrpc_error_msg(),
                        $method,
                        print_r($data, true)
                    ));

                    if ($errno === MOLLOM_REFRESH) {
                        // Retrieve a list of valid Mollom servers from mollom.com:
                        $servers = $this->xmlrpc(
                            'http://xmlrpc.mollom.com/' . MOLLOM_API_VERSION,
                            'mollom.getServerList',
                            $this->authentication()
                        );

                    // Store the updated list of servers in the database:
                        // @todo variable_set('mollom_servers', $servers);
                    } elseif ($errno === MOLLOM_ERROR) {
                        return $result;
                    } elseif ($errno === MOLLOM_REDIRECT) {
                        // Do nothing, we select the next client automatically.
                    }

                    // Reset the XMLRPC error:
                    $this->xmlrpc_error(0);  // FIXME: this is crazy.
                } else {
                    common_debug('Result = ' . print_r($result, true));
                    return $result;
                }
            }
        }

        // If none of the servers worked, activate the fallback mechanism:
        common_debug('none of the servers worked');
        // _mollom_fallback();

      // If everything failed, we reset the server list to force Mollom to request a new list:
      //TODO variable_set('mollom_servers', array());
    }

    /**
     * This function generate an array with all the information required to
     * authenticate against Mollom. To prevent that requests are forged and
     * that you are impersonated, each request is signed with a hash computed
     * based on a private key and a timestamp.
     *
     * Both the client and the server share the secret key that is used to
     * create the authentication hash based on a timestamp.  They both hash
     * the timestamp with the secret key, and if the hashes match, the
     * authenticity of the message has been validated.
     *
     * To avoid that someone can intercept a (hash, timestamp)-pair and
     * use that to impersonate a client, Mollom will reject the request
     * when the timestamp is more than 15 minutes off.
     *
     * Make sure your server's time is synchronized with the world clocks,
     * and that you don't share your private key with anyone else.
     */
    private function authentication()
    {
        $public_key = $this->public_key;
        $private_key = $this->private_key;

        $hash = hash_hmac('sha1', $private_key, $private_key, true);

        // Store everything in an array. Elsewhere in the code, we'll add the
        // acutal data before we pass it onto the XML-RPC library:
        $data['public_key'] = $public_key;
        $data['time'] = $time;
        $data['hash'] = $hash;

        return $data;
    }

    public function xmlrpc($url)
    {
        //require_once './includes/xmlrpc.inc';
        $args = func_get_args();
        return call_user_func_array(['MollomPlugin', '_xmlrpc'], $args);
    }

    /**
     * Recursively turn a data structure into objects with 'data' and 'type' attributes.
     *
     * @param $data
     *   The data structure.
     * @param  $type
     *   Optional type assign to $data.
     * @return
     *   Object.
     */
    public function xmlrpc_value($data, $type = false)
    {
        $xmlrpc_value = new stdClass();
        $xmlrpc_value->data = $data;
        if (!$type) {
            $type = $this->xmlrpc_value_calculate_type($xmlrpc_value);
        }
        $xmlrpc_value->type = $type;
        if ($type === 'struct') {
            // Turn all the values in the array into new xmlrpc_values
            foreach ($xmlrpc_value->data as $key => $value) {
                $xmlrpc_value->data[$key] = $this->xmlrpc_value($value);
            }
        }
        if ($type === 'array') {
            for ($i = 0, $j = count($xmlrpc_value->data); $i < $j; ++$i) {
                $xmlrpc_value->data[$i] = $this->xmlrpc_value($xmlrpc_value->data[$i]);
            }
        }
        return $xmlrpc_value;
    }

    /**
     * Map PHP type to XML-RPC type.
     *
     * @param $xmlrpc_value
     *   Variable whose type should be mapped.
     * @return
     *   XML-RPC type as string.
     * @see
     *   http://www.xmlrpc.com/spec#scalars
     */
    public function xmlrpc_value_calculate_type(&$xmlrpc_value)
    {
        // http://www.php.net/gettype: Never use gettype() to test for a certain type [...] Instead, use the is_* functions.
        if (is_bool($xmlrpc_value->data)) {
            return 'boolean';
        } elseif (is_double($xmlrpc_value->data)) {
            return 'double';
        } elseif (is_int($xmlrpc_value->data)) {
            return 'int';
        } elseif (is_array($xmlrpc_value->data)) {
            // empty or integer-indexed arrays are 'array', string-indexed arrays 'struct'
            return empty($xmlrpc_value->data)
                   || (range(0, count($xmlrpc_value->data) - 1) === array_keys($xmlrpc_value->data) ? 'array' : 'struct');
        }
        if (is_object($xmlrpc_value->data)) {
            if ($xmlrpc_value->data->is_date) {
                return 'date';
            } elseif ($xmlrpc_value->data->is_base64) {
                return 'base64';
            }
            $xmlrpc_value->data = get_object_vars($xmlrpc_value->data);
            return 'struct';
        }
        // default
        return 'string';
    }

    /**
     * Generate XML representing the given value.
     *
     * @param $xmlrpc_value
     * @return
     *   XML representation of value.
     */
    public function xmlrpc_value_get_xml($xmlrpc_value)
    {
        switch ($xmlrpc_value->type) {
        case 'boolean':
          return '<boolean>'. (($xmlrpc_value->data) ? '1' : '0') .'</boolean>';
          break;
        case 'int':
          return '<int>'. $xmlrpc_value->data .'</int>';
          break;
        case 'double':
          return '<double>'. $xmlrpc_value->data .'</double>';
          break;
        case 'string':
          // Note: we don't escape apostrophes because of the many blogging clients
          // that don't support numerical entities (and XML in general) properly.
          return '<string>'. htmlspecialchars($xmlrpc_value->data) .'</string>';
          break;
        case 'array':
          $return = "<array><data>\n";
          foreach ($xmlrpc_value->data as $item) {
              $return .= '  <value>'. $this->xmlrpc_value_get_xml($item) ."</value>\n";
          }
          $return .= '</data></array>';
          return $return;
          break;
        case 'struct':
          $return = "<struct>\n";
          foreach ($xmlrpc_value->data as $name => $value) {
              $return .= '  <member><name>' . htmlentities($name) . '</name><value>';
              $return .= $this->xmlrpc_value_get_xml($value) . "</value></member>\n";
          }
          $return .= '</struct>';
          return $return;
          break;
        case 'date':
          return $this->xmlrpc_date_get_xml($xmlrpc_value->data);
          break;
        case 'base64':
          return $this->xmlrpc_base64_get_xml($xmlrpc_value->data);
          break;
      }
        return false;
    }

    /**
     * Perform an HTTP request.
     *
     * This is a flexible and powerful HTTP client implementation. Correctly handles
     * GET, POST, PUT or any other HTTP requests. Handles redirects.
     *
     * @param $url
     *   A string containing a fully qualified URI.
     * @param $headers
     *   An array containing an HTTP header => value pair.
     * @param $method
     *   A string defining the HTTP request to use.
     * @param $data
     *   A string containing data to include in the request.
     * @param $retry
     *   An integer representing how many times to retry the request in case of a
     *   redirect.
     * @return
     *   An object containing the HTTP request headers, response code, headers,
     *   data and redirect status.
     */
    public function http_request(
        $url,
        $headers = [],
        $method  = 'GET',
        $data    = null,
        $retry   = 3
    ) {
        global $db_prefix;

        $result = new stdClass();

        // Parse the URL and make sure we can handle the schema.
        $uri = parse_url($url);

        if ($uri === false) {
            $result->error = 'unable to parse URL';
            return $result;
        }

        if (!array_key_exists('scheme', $uri)) {
            $result->error = 'missing schema';
            return $result;
        }

        switch ($uri['scheme']) {
        case 'http':
          $port = isset($uri['port']) ? $uri['port'] : 80;
          $host = $uri['host'] . ($port != 80 ? ':'. $port : '');
          $fp = @fsockopen($uri['host'], $port, $errno, $errstr, 15);
          break;
        case 'https':
          // Note: Only works for PHP 4.3 compiled with OpenSSL.
          $port = isset($uri['port']) ? $uri['port'] : 443;
          $host = $uri['host'] . ($port != 443 ? ':'. $port : '');
          $fp = @fsockopen('ssl://'. $uri['host'], $port, $errno, $errstr, 20);
          break;
        default:
          $result->error = 'invalid schema '. $uri['scheme'];
          return $result;
      }

        // Make sure the socket opened properly.
        if ($fp === false) {
            // When a network error occurs, we use a negative number so it does not
            // clash with the HTTP status codes.
            $result->code = -$errno;
            $result->error = trim($errstr);

            // Mark that this request failed. This will trigger a check of the web
            // server's ability to make outgoing HTTP requests the next time that
            // requirements checking is performed.
            // @see system_requirements()
            // @todo variable_set('drupal_http_request_fails', TRUE);

            return $result;
        }

        // Construct the path to act on.
        $path = $uri['path'] ?? '/';
        if (array_key_exists('query', $uri)) {
            $path .= '?' . $uri['query'];
        }

        // Create HTTP request.
        $defaults = [
            // RFC 2616: "non-standard ports MUST, default ports MAY be included".
            // We don't add the port to prevent from breaking rewrite rules checking the
            // host that do not take into account the port number.
            'Host'           => "Host: {$host}",
            'User-Agent'     => 'User-Agent: Drupal (+http://drupal.org/)',
            'Content-Length' => 'Content-Length: ' . strlen($data),
        ];

        // If the server url has a user then attempt to use basic authentication
        if (array_key_exists('user', $uri)) {
            $defaults['Authorization'] = 'Authorization: Basic '
                                       . base64_encode($uri['user']
                                       . (!empty($uri['pass']) ? ':' . $uri['pass'] : ''));
        }

        // If the database prefix is being used by SimpleTest to run the tests in a copied
        // database then set the user-agent header to the database prefix so that any
        // calls to other Drupal pages will run the SimpleTest prefixed database. The
        // user-agent is used to ensure that multiple testing sessions running at the
        // same time won't interfere with each other as they would if the database
        // prefix were stored statically in a file or database variable.
        if (
            is_string($db_prefix)
            && preg_match('/^simpletest\d+$/', $db_prefix, $matches)
        ) {
            $defaults['User-Agent'] = 'User-Agent: ' . $matches[0];
        }

        foreach ($headers as $header => $value) {
            $defaults[$header] = $header . ': ' . $value;
        }

        $request = $method . ' ' . $path . " HTTP/1.0\r\n";
        $request .= implode("\r\n", $defaults);
        $request .= "\r\n\r\n";
        $request .= $data;

        $result->request = $request;

        fwrite($fp, $request);

        // Fetch response.
        $response = '';
        while (!feof($fp) && ($chunk = fread($fp, 1024)) !== false) {
            $response .= $chunk;
        }
        fclose($fp);

        // Parse response.
        [$split, $result->data] = explode("\r\n\r\n", $response, 2);
        $split = preg_split("/\r\n|\n|\r/", $split);

        [$protocol, $code, $text] = explode(' ', trim(array_shift($split)), 3);
        $result->headers = [];

        // Parse headers.
        while (($line = trim(array_shift($split))) !== '') {
            [$header, $value] = explode(':', $line, 2);
            if (
                array_key_exists($header, $result->headers)
                && $header === 'Set-Cookie'
            ) {
                // RFC 2109: the Set-Cookie response header comprises the token Set-
                // Cookie:, followed by a comma-separated list of one or more cookies.
                $result->headers[$header] .= ',' . trim($value);
            } else {
                $result->headers[$header] = trim($value);
            }
        }

        $responses = [
            100 => 'Continue', 101 => 'Switching Protocols',
            200 => 'OK', 201 => 'Created', 202 => 'Accepted', 203 => 'Non-Authoritative Information', 204 => 'No Content', 205 => 'Reset Content', 206 => 'Partial Content',
            300 => 'Multiple Choices', 301 => 'Moved Permanently', 302 => 'Found', 303 => 'See Other', 304 => 'Not Modified', 305 => 'Use Proxy', 307 => 'Temporary Redirect',
            400 => 'Bad Request', 401 => 'Unauthorized', 402 => 'Payment Required', 403 => 'Forbidden', 404 => 'Not Found', 405 => 'Method Not Allowed', 406 => 'Not Acceptable', 407 => 'Proxy Authentication Required', 408 => 'Request Time-out', 409 => 'Conflict', 410 => 'Gone', 411 => 'Length Required', 412 => 'Precondition Failed', 413 => 'Request Entity Too Large', 414 => 'Request-URI Too Large', 415 => 'Unsupported Media Type', 416 => 'Requested range not satisfiable', 417 => 'Expectation Failed',
            500 => 'Internal Server Error', 501 => 'Not Implemented', 502 => 'Bad Gateway', 503 => 'Service Unavailable', 504 => 'Gateway Time-out', 505 => 'HTTP Version not supported',
        ];
        // RFC 2616 states that all unknown HTTP codes must be treated the same as the
        // base code in their class.
        if (!array_key_exists($code, $responses)) {
            $code = floor($code / 100) * 100;
        }

        switch ($code) {
        case 200: // OK
        case 304: // Not modified
          break;
        case 301: // Moved permanently
        case 302: // Moved temporarily
        case 307: // Moved temporarily
          $location = $result->headers['Location'];

          if ($retry) {
              $result = drupal_http_request($result->headers['Location'], $headers, $method, $data, --$retry);
              $result->redirect_code = $result->code;
          }
          $result->redirect_url = $location;
          break;
        default:
          $result->error = $text;
      }

        $result->code = $code;
        return $result;
    }

    /**
     * Construct an object representing an XML-RPC message.
     *
     * @param $message
     *   String containing XML as defined at http://www.xmlrpc.com/spec
     * @return
     *   Object
     */
    public function xmlrpc_message($message)
    {
        $xmlrpc_message = new stdClass();
        // The stack used to keep track of the current array/struct
        $xmlrpc_message->array_structs = [];
        // The stack used to keep track of if things are structs or array
        $xmlrpc_message->array_structs_types = [];
        // A stack as well
        $xmlrpc_message->current_struct_name = [];
        $xmlrpc_message->message = $message;
        return $xmlrpc_message;
    }

    /**
     * Parse an XML-RPC message. If parsing fails, the faultCode and faultString
     * will be added to the message object.
     *
     * @param $xmlrpc_message
     *   Object generated by xmlrpc_message()
     * @return
     *   TRUE if parsing succeeded; FALSE otherwise
     */
    public function xmlrpc_message_parse(&$xmlrpc_message)
    {
        // First remove the XML declaration
        $xmlrpc_message->message = preg_replace(
            '/<\?xml(.*)?\?'.'>/',
            '',
            $xmlrpc_message->message
        );
        if (trim($xmlrpc_message->message) === '') {
            return false;
        }
        $xmlrpc_message->_parser = xml_parser_create();
        // Set XML parser to take the case of tags into account.
        xml_parser_set_option(
            $xmlrpc_message->_parser,
            XML_OPTION_CASE_FOLDING,
            false
        );
        // Set XML parser callback functions
        xml_set_element_handler(
            $xmlrpc_message->_parser,
            ['MollomPlugin', 'xmlrpc_message_tag_open'],
            ['MollomPlugin', 'xmlrpc_message_tag_close']
        );
        xml_set_character_data_handler(
            $xmlrpc_message->_parser,
            ['MollomPlugin', 'xmlrpc_message_cdata']
        );
        $this->xmlrpc_message_set($xmlrpc_message);
        if (!xml_parse($xmlrpc_message->_parser, $xmlrpc_message->message)) {
            return false;
        }
        xml_parser_free($xmlrpc_message->_parser);
        // Grab the error messages, if any
        $xmlrpc_message = $this->xmlrpc_message_get();
        if ($xmlrpc_message->messagetype === 'fault') {
            $xmlrpc_message->fault_code = $xmlrpc_message->params[0]['faultCode'];
            $xmlrpc_message->fault_string = $xmlrpc_message->params[0]['faultString'];
        }
        return true;
    }

    /**
     * Store a copy of the $xmlrpc_message object temporarily.
     *
     * @param $value
     *   Object
     * @return
     *   The most recently stored $xmlrpc_message
     */
    public function xmlrpc_message_set($value = null)
    {
        static $xmlrpc_message;
        if ($value) {
            $xmlrpc_message = $value;
        }
        return $xmlrpc_message;
    }

    public function xmlrpc_message_get()
    {
        return $this->xmlrpc_message_set();
    }

    public function xmlrpc_message_tag_open($parser, $tag, $attr)
    {
        $xmlrpc_message = $this->xmlrpc_message_get();
        $xmlrpc_message->current_tag_contents = '';
        $xmlrpc_message->last_open = $tag;
        switch ($tag) {
        case 'methodCall':
        case 'methodResponse':
        case 'fault':
          $xmlrpc_message->messagetype = $tag;
          break;
        // Deal with stacks of arrays and structs
        case 'data':
          $xmlrpc_message->array_structs_types[] = 'array';
          $xmlrpc_message->array_structs[] = array();
          break;
        case 'struct':
          $xmlrpc_message->array_structs_types[] = 'struct';
          $xmlrpc_message->array_structs[] = array();
          break;
      }
        $this->xmlrpc_message_set($xmlrpc_message);
    }

    public function xmlrpc_message_cdata($parser, $cdata)
    {
        $xmlrpc_message = $this->xmlrpc_message_get();
        $xmlrpc_message->current_tag_contents .= $cdata;
        $this->xmlrpc_message_set($xmlrpc_message);
    }

    public function xmlrpc_message_tag_close($parser, $tag)
    {
        $xmlrpc_message = $this->xmlrpc_message_get();
        $value_flag = false;
        switch ($tag) {
        case 'int':
        case 'i4':
          $value = (int)trim($xmlrpc_message->current_tag_contents);
          $value_flag = true;
          break;
        case 'double':
          $value = (double)trim($xmlrpc_message->current_tag_contents);
          $value_flag = true;
          break;
        case 'string':
          $value = $xmlrpc_message->current_tag_contents;
          $value_flag = true;
          break;
        case 'dateTime.iso8601':
          $value = xmlrpc_date(trim($xmlrpc_message->current_tag_contents));
          // $value = $iso->getTimestamp();
          $value_flag = true;
          break;
        case 'value':
          // If no type is indicated, the type is string
          // We take special care for empty values
          if (trim($xmlrpc_message->current_tag_contents) != '' || (isset($xmlrpc_message->last_open) && ($xmlrpc_message->last_open == 'value'))) {
              $value = (string)$xmlrpc_message->current_tag_contents;
              $value_flag = true;
          }
          unset($xmlrpc_message->last_open);
          break;
        case 'boolean':
          $value = (boolean)trim($xmlrpc_message->current_tag_contents);
          $value_flag = true;
          break;
        case 'base64':
          $value = base64_decode(trim($xmlrpc_message->current_tag_contents));
          $value_flag = true;
          break;
        // Deal with stacks of arrays and structs
        case 'data':
        case 'struct':
          $value = array_pop($xmlrpc_message->array_structs);
          array_pop($xmlrpc_message->array_structs_types);
          $value_flag = true;
          break;
        case 'member':
          array_pop($xmlrpc_message->current_struct_name);
          break;
        case 'name':
          $xmlrpc_message->current_struct_name[] = trim($xmlrpc_message->current_tag_contents);
          break;
        case 'methodName':
          $xmlrpc_message->methodname = trim($xmlrpc_message->current_tag_contents);
          break;
      }

        if ($value_flag) {
            if (count($xmlrpc_message->array_structs) > 0) {
                // Add value to struct or array
                if ($xmlrpc_message->array_structs_types[count($xmlrpc_message->array_structs_types) - 1] === 'struct') {
                    // Add to struct
                    $xmlrpc_message->array_structs[count($xmlrpc_message->array_structs) - 1][$xmlrpc_message->current_struct_name[count($xmlrpc_message->current_struct_name) - 1]] = $value;
                } else {
                    // Add to array
                    $xmlrpc_message->array_structs[count($xmlrpc_message->array_structs) - 1][] = $value;
                }
            } else {
                // Just add as a parameter
                $xmlrpc_message->params[] = $value;
            }
        }
        if (!in_array($tag, ['data', 'struct', 'member'])) {
            $xmlrpc_message->current_tag_contents = '';
        }
        $this->xmlrpc_message_set($xmlrpc_message);
    }

    /**
     * Construct an object representing an XML-RPC request
     *
     * @param $method
     *   The name of the method to be called
     * @param $args
     *   An array of parameters to send with the method.
     * @return
     *   Object
     */
    public function xmlrpc_request($method, $args)
    {
        $xmlrpc_request = new stdClass();
        $xmlrpc_request->method = $method;
        $xmlrpc_request->args = $args;
        $xmlrpc_request->xml = <<<EOD
    <?xml version="1.0"?>
    <methodCall>
    <methodName>{$xmlrpc_request->method}</methodName>
    <params>

EOD;

        foreach ($xmlrpc_request->args as $arg) {
            $xmlrpc_request->xml .= '<param><value>';
            $v = $this->xmlrpc_value($arg);
            $xmlrpc_request->xml .= $this->xmlrpc_value_get_xml($v);
            $xmlrpc_request->xml .= "</value></param>\n";
        }
        $xmlrpc_request->xml .= '</params></methodCall>';
        return $xmlrpc_request;
    }


    public function xmlrpc_error($code = null, $message = null, $reset = false)
    {
        static $xmlrpc_error;
        if (!is_null($code)) {
            $xmlrpc_error = new stdClass();
            $xmlrpc_error->is_error = true;
            $xmlrpc_error->code = $code;
            $xmlrpc_error->message = $message;
        } elseif ($reset) {
            $xmlrpc_error = null;
        }
        return $xmlrpc_error;
    }

    public function xmlrpc_error_get_xml($xmlrpc_error)
    {
        return <<<EOD
    <methodResponse>
      <fault>
      <value>
        <struct>
        <member>
          <name>faultCode</name>
          <value><int>{$xmlrpc_error->code}</int></value>
        </member>
        <member>
          <name>faultString</name>
          <value><string>{$xmlrpc_error->message}</string></value>
        </member>
        </struct>
      </value>
      </fault>
    </methodResponse>

EOD;
    }

    public function xmlrpc_date($time)
    {
        $xmlrpc_date = new stdClass();
        $xmlrpc_date->is_date = true;
        // $time can be a PHP timestamp or an ISO one
        if (is_numeric($time)) {
            $xmlrpc_date->year = gmdate('Y', $time);
            $xmlrpc_date->month = gmdate('m', $time);
            $xmlrpc_date->day = gmdate('d', $time);
            $xmlrpc_date->hour = gmdate('H', $time);
            $xmlrpc_date->minute = gmdate('i', $time);
            $xmlrpc_date->second = gmdate('s', $time);
            $xmlrpc_date->iso8601 = gmdate('Ymd\TH:i:s', $time);
        } else {
            $xmlrpc_date->iso8601 = $time;
            $time = str_replace(array('-', ':'), '', $time);
            $xmlrpc_date->year = substr($time, 0, 4);
            $xmlrpc_date->month = substr($time, 4, 2);
            $xmlrpc_date->day = substr($time, 6, 2);
            $xmlrpc_date->hour = substr($time, 9, 2);
            $xmlrpc_date->minute = substr($time, 11, 2);
            $xmlrpc_date->second = substr($time, 13, 2);
        }
        return $xmlrpc_date;
    }

    public function xmlrpc_date_get_xml($xmlrpc_date)
    {
        return '<dateTime.iso8601>'
               . $xmlrpc_date->year
               . $xmlrpc_date->month
               . $xmlrpc_date->day
               . 'T' . $xmlrpc_date->hour
               . ':'. $xmlrpc_date->minute
               . ':'. $xmlrpc_date->second
               . '</dateTime.iso8601>';
    }

    public function xmlrpc_base64($data)
    {
        $xmlrpc_base64 = new stdClass();
        $xmlrpc_base64->is_base64 = true;
        $xmlrpc_base64->data = $data;
        return $xmlrpc_base64;
    }

    public function xmlrpc_base64_get_xml($xmlrpc_base64)
    {
        return '<base64>'. base64_encode($xmlrpc_base64->data) .'</base64>';
    }

    /**
    * Execute an XML remote procedural call. This is private function; call xmlrpc()
    * in common.inc instead of this function.
    *
    * @return
    *   A $xmlrpc_message object if the call succeeded; FALSE if the call failed
    */
    public function _xmlrpc()
    {
        $args = func_get_args();
        $url = array_shift($args);
        $this->xmlrpc_clear_error();
        if (is_array($args[0])) {
            $method = 'system.multicall';
            $multicall_args = [];
            foreach ($args[0] as $call) {
                $multicall_args[] = [
                    'methodName' => array_shift($call),
                    'params'     => $call,
                ];
            }
            $args = [$multicall_args];
        } else {
            $method = array_shift($args);
        }
        $xmlrpc_request = $this->xmlrpc_request($method, $args);
        $result = $this->http_request($url, [
            'Content-Type' => 'text/xml',
        ], 'POST', $xmlrpc_request->xml);
        if ($result->code !== 200) {
            $this->xmlrpc_error($result->code, $result->error);
            return false;
        }
        $message = $this->xmlrpc_message($result->data);
        // Now parse what we've got back
        if (!$this->xmlrpc_message_parse($message)) {
            // XML error
            $this->xmlrpc_error(-32700, t('Parse error. Not well formed'));
            return false;
        }
        // Is the message a fault?
        if ($message->messagetype === 'fault') {
            $this->xmlrpc_error($message->fault_code, $message->fault_string);
            return false;
        }
        // Message must be OK
        return $message->params[0];
    }

    /**
     * Returns the last XML-RPC client error number
     */
    public function xmlrpc_errno()
    {
        return $this->xmlrpc_error()->code ?? null;
    }

    /**
     * Returns the last XML-RPC client error message
     */
    public function xmlrpc_error_msg()
    {
        return xmlrpc_error()->message ?? null;
    }

    /**
     * Clears any previous error.
     */
    public function xmlrpc_clear_error()
    {
        $this->xmlrpc_error(null, null, true);
    }
}