<?php

use GuzzleHttp\Client as HttpClient;

/*
 +-----------------------------------------------------------------------+
 | This file is part of the Roundcube Webmail client                     |
 |                                                                       |
 | Copyright (C) The Roundcube Dev Team                                  |
 | Copyright (C) Kolab Systems AG                                        |
 |                                                                       |
 | Licensed under the GNU General Public License version 3 or            |
 | any later version with exceptions for skins & plugins.                |
 | See the README file for a full license statement.                     |
 |                                                                       |
 | PURPOSE:                                                              |
 |   Framework base class providing core functions and holding           |
 |   instances of all 'global' objects like db- and storage-connections  |
 +-----------------------------------------------------------------------+
 | Author: Thomas Bruederli <roundcube@gmail.com>                        |
 +-----------------------------------------------------------------------+
*/

/**
 * Base class of the Roundcube Framework
 * implemented as singleton
 */
class rcube
{
    // Init options
    public const INIT_WITH_DB = 1;
    public const INIT_WITH_PLUGINS = 2;

    // Request status
    public const REQUEST_VALID = 0;
    public const REQUEST_ERROR_URL = 1;
    public const REQUEST_ERROR_TOKEN = 2;

    public const DEBUG_LINE_LENGTH = 4096;

    /** @var rcube_config Stores instance of rcube_config */
    public $config;

    /** @var ?rcube_db SQL database handler */
    public $db;

    /** @var Memcache|false|null Memcache cache handler */
    public $memcache;

    /** @var Memcached|false|null Memcached cache handler */
    public $memcached;

    /** @var Redis|false|null Redis cache handler */
    public $redis;

    /** @var ?rcube_session Session handler */
    public $session;

    /** @var ?rcube_smtp SMTP handler */
    public $smtp;

    /** @var ?rcube_storage Storage (IMAP) handler */
    public $storage;

    /** @var ?rcube_output Output handler */
    public $output;

    /** @var rcube_plugin_api|rcube_dummy_plugin_api Instance of rcube_plugin_api */
    public $plugins;

    /** @var ?rcube_user User database handler */
    public $user;

    /** @var ?string Temporary user email */
    public $user_email;

    /** @var ?string Temporary user password */
    public $password;

    /** @var int Request status */
    public $request_status = 0;

    /** @var array Localization */
    protected $texts;

    /** @var array<rcube_cache|null> Initialized cache objects */
    protected $caches = [];

    /** @var array Registered shutdown functions */
    protected $shutdown_functions = [];

    /** @var ?rcube Singleton instance of rcube */
    protected static $instance;

    /**
     * This implements the 'singleton' design pattern
     *
     * @param int    $mode Options to initialize with this instance. See rcube::INIT_WITH_* constants
     * @param string $env  Environment name to run (e.g. live, dev, test)
     *
     * @return rcube The one and only instance
     */
    public static function get_instance($mode = 0, $env = '')
    {
        if (!self::$instance) {
            self::$instance = new self($env);
            self::$instance->init($mode);
        }

        return self::$instance;
    }

    /**
     * Private constructor
     *
     * @param string $env Environment name to run (e.g. live, dev, test)
     */
    protected function __construct($env = '')
    {
        // load configuration
        $this->config = new rcube_config($env);
        $this->plugins = new rcube_dummy_plugin_api();

        register_shutdown_function([$this, 'shutdown']);
    }

    /**
     * Initial startup function
     *
     * @param int $mode Options to initialize with this instance. See rcube::INIT_WITH_* constants
     */
    protected function init($mode = 0)
    {
        // initialize syslog
        if ($this->config->get('log_driver') == 'syslog') {
            $syslog_id = $this->config->get('syslog_id', 'roundcube');
            $syslog_facility = $this->config->get('syslog_facility', \LOG_USER);
            openlog($syslog_id, \LOG_ODELAY, $syslog_facility);
        }

        // connect to database
        if ($mode & self::INIT_WITH_DB) {
            $this->get_dbh();
        }

        // create plugin API and load plugins
        if ($mode & self::INIT_WITH_PLUGINS) {
            $this->plugins = rcube_plugin_api::get_instance();
        }
    }

    /**
     * Get the current database connection
     *
     * @return rcube_db Database object
     */
    public function get_dbh()
    {
        if (!$this->db) {
            $this->db = rcube_db::factory(
                $this->config->get('db_dsnw'),
                $this->config->get('db_dsnr'),
                $this->config->get('db_persistent')
            );

            $this->db->set_debug((bool) $this->config->get('sql_debug'));
        }

        return $this->db;
    }

    /**
     * Get global handle for memcache access
     *
     * @return Memcache|false The memcache engine
     */
    public function get_memcache()
    {
        if (!isset($this->memcache)) {
            $this->memcache = rcube_cache_memcache::engine();
        }

        return $this->memcache;
    }

    /**
     * Get global handle for memcached access
     *
     * @return Memcached|false The memcached engine
     */
    public function get_memcached()
    {
        if (!isset($this->memcached)) {
            $this->memcached = rcube_cache_memcached::engine();
        }

        return $this->memcached;
    }

    /**
     * Get global handle for redis access
     *
     * @return Redis|false The redis engine
     */
    public function get_redis()
    {
        if (!isset($this->redis)) {
            $this->redis = rcube_cache_redis::engine();
        }

        return $this->redis;
    }

    /**
     * Initialize and get user cache object
     *
     * @param string     $name    Cache identifier
     * @param string     $type    Cache type ('db', 'apc', 'memcache', 'redis')
     * @param string|int $ttl     Expiration time for cache items
     * @param bool       $packed  Enables/disables data serialization
     * @param bool       $indexed Use indexed cache
     *
     * @return rcube_cache|null User cache object
     */
    public function get_cache($name, $type = 'db', $ttl = 0, $packed = true, $indexed = false)
    {
        if (!isset($this->caches[$name]) && ($userid = $this->get_user_id())) {
            $this->caches[$name] = rcube_cache::factory($type, $userid, $name, $ttl, $packed, $indexed);
        }

        return $this->caches[$name] ?? null;
    }

    /**
     * Initialize and get shared cache object
     *
     * @param string $name   Cache identifier
     * @param bool   $packed Enables/disables data serialization
     *
     * @return rcube_cache|null Shared cache object, Null if the cache is disabled
     */
    public function get_cache_shared($name, $packed = true)
    {
        $shared_name = "shared_{$name}";

        if (!array_key_exists($shared_name, $this->caches)) {
            $opt = strtolower($name) . '_cache';
            $type = $this->config->get($opt);
            $ttl = $this->config->get($opt . '_ttl');

            if (!$type) {
                // cache is disabled
                return $this->caches[$shared_name] = null;
            }

            if ($ttl === null) {
                $ttl = $this->config->get('shared_cache_ttl', '10d');
            }

            $this->caches[$shared_name] = rcube_cache::factory($type, null, $name, $ttl, $packed);
        }

        return $this->caches[$shared_name];
    }

    /**
     * Initialize HTTP client
     *
     * @param array $options Configuration options
     *
     * @return HttpClient HTTP client
     */
    public function get_http_client($options = [])
    {
        $defaults = ['timeout' => 30, 'connect_timeout' => 5, 'read_timeout' => 120];

        return new HttpClient($options + ($this->config->get('http_client') ?? []) + $defaults);
    }

    /**
     * Create SMTP object and connect to server
     *
     * @param bool $connect True if connection should be established
     */
    public function smtp_init($connect = false)
    {
        $this->smtp = new rcube_smtp();

        if ($connect) {
            $this->smtp->connect();
        }
    }

    /**
     * Initialize and get storage object
     *
     * @return rcube_storage Storage object
     */
    public function get_storage()
    {
        // already initialized
        if (!is_object($this->storage)) {
            $this->storage_init();
        }

        return $this->storage;
    }

    /**
     * Initialize storage object
     */
    public function storage_init()
    {
        // already initialized
        if (is_object($this->storage)) {
            return;
        }

        $driver = $this->config->get('storage_driver', 'imap');
        $driver_class = "rcube_{$driver}";

        if (!class_exists($driver_class)) {
            self::raise_error([
                'code' => 700,
                'message' => "Storage driver class ({$driver}) not found!",
            ], true, true);
        }

        // Initialize storage object
        $this->storage = new $driver_class();

        // set class options
        $options = [
            'auth_type' => $this->config->get("{$driver}_auth_type", 'check'),
            'auth_cid' => $this->config->get("{$driver}_auth_cid"),
            'auth_pw' => $this->config->get("{$driver}_auth_pw"),
            'debug' => (bool) $this->config->get("{$driver}_debug"),
            'force_caps' => (bool) $this->config->get("{$driver}_force_caps"),
            'disabled_caps' => $this->config->get("{$driver}_disabled_caps"),
            'socket_options' => $this->config->get("{$driver}_conn_options"),
            'timeout' => (int) $this->config->get("{$driver}_timeout"),
            'skip_deleted' => (bool) $this->config->get('skip_deleted'),
            'driver' => $driver,
        ];

        if (!empty($_SESSION['storage_host'])) {
            $options['language'] = $_SESSION['language'];
            $options['host'] = $_SESSION['storage_host'];
            $options['user'] = $_SESSION['username'];
            $options['port'] = $_SESSION['storage_port'];
            $options['ssl'] = $_SESSION['storage_ssl'];
            $options['password'] = $this->decrypt($_SESSION['password']);
            $_SESSION[$driver . '_host'] = $_SESSION['storage_host'];
        }

        $options = $this->plugins->exec_hook('storage_init', $options);

        // for backward compat. (deprecated, to be removed)
        $options = $this->plugins->exec_hook('imap_init', $options);

        $this->storage->set_options($options);
        $this->set_storage_prop();

        // subscribe to 'storage_connected' hook for session logging
        if ($this->config->get('imap_log_session', false)) {
            $this->plugins->register_hook('storage_connected', [$this, 'storage_log_session']);
        }
    }

    /**
     * Set storage parameters.
     */
    protected function set_storage_prop()
    {
        $storage = $this->get_storage();

        // set pagesize from config
        $pagesize = $this->config->get('mail_pagesize');
        if (!$pagesize) {
            $pagesize = $this->config->get('pagesize', 50);
        }

        $storage->set_pagesize($pagesize);
        $storage->set_charset($this->config->get('default_charset', RCUBE_CHARSET));

        // enable caching of mail data
        $driver = $this->config->get('storage_driver', 'imap');
        $storage_cache = $this->config->get("{$driver}_cache");
        $messages_cache = $this->config->get('messages_cache');

        // for backward compatibility
        if ($storage_cache === null && $messages_cache === null && $this->config->get('enable_caching')) {
            $storage_cache = 'db';
            $messages_cache = true;
        }

        if ($storage_cache) {
            $storage->set_caching($storage_cache);
        }

        if ($messages_cache) {
            $storage->set_messages_caching(true);
        }
    }

    /**
     * Set special folders type association.
     * This must be done AFTER connecting to the server!
     */
    protected function set_special_folders()
    {
        $storage = $this->get_storage();
        $folders = $storage->get_special_folders(true);
        $prefs = [];

        // check SPECIAL-USE flags on IMAP folders
        foreach ($folders as $type => $folder) {
            $idx = $type . '_mbox';
            if ($folder !== $this->config->get($idx)) {
                $prefs[$idx] = $folder;
            }
        }

        // Some special folders differ, update user preferences
        if (!empty($prefs) && $this->user) {
            $this->user->save_prefs($prefs);
        }

        // create default folders (on login)
        if ($this->config->get('create_default_folders')) {
            $storage->create_default_folders();
        }
    }

    /**
     * Callback for IMAP connection events to log session identifiers
     *
     * @param array $args Callback arguments
     */
    public function storage_log_session($args)
    {
        if (!empty($args['session']) && session_id()) {
            $this->write_log('imap_session', $args['session']);
        }
    }

    /**
     * Create session object and start the session.
     */
    public function session_init()
    {
        // Ignore in CLI mode or when session started (Installer?)
        if (empty($_SERVER['REMOTE_ADDR']) || session_id()) {
            return;
        }

        $storage = $this->config->get('session_storage', 'db');
        $sess_name = $this->config->get('session_name');
        $sess_domain = $this->config->get('session_domain');
        $sess_path = $this->config->get('session_path');
        $sess_samesite = $this->config->get('session_samesite');
        $lifetime = $this->config->get('session_lifetime', 0) * 60;
        $is_secure = rcube_utils::https_check();

        // set session domain
        if ($sess_domain) {
            ini_set('session.cookie_domain', $sess_domain);
        }
        // set session path
        if ($sess_path) {
            ini_set('session.cookie_path', $sess_path);
        }
        // set session samesite attribute
        if ($sess_samesite) {
            ini_set('session.cookie_samesite', $sess_samesite);
        }
        // set session garbage collecting time according to session_lifetime
        if ($lifetime) {
            ini_set('session.gc_maxlifetime', $lifetime);
        }

        // set session cookie lifetime so it never expires (#5961)
        ini_set('session.cookie_lifetime', 0);
        ini_set('session.cookie_secure', $is_secure);
        ini_set('session.name', $sess_name ?: 'roundcube_sessid');
        ini_set('session.use_cookies', 1);
        ini_set('session.use_only_cookies', 1);
        ini_set('session.cookie_httponly', 1);

        // Make sure session garbage collector is enabled when using custom handlers (#6560)
        // Note: Use session.gc_divisor to control accuracy
        if ($storage != 'php' && !ini_get('session.gc_probability')) {
            ini_set('session.gc_probability', 1);
        }

        // Start the session
        $this->session = rcube_session::factory($this->config);
        $this->session->register_gc_handler([$this, 'gc']);
        $this->session->start();
    }

    /**
     * Garbage collector - cache/temp cleaner
     */
    public function gc()
    {
        rcube_cache::gc();
        $this->get_storage()->cache_gc();
        $this->gc_temp();
    }

    /**
     * Garbage collector function for temporary files.
     * Removes temporary files and upload information older than temp_dir_ttl.
     */
    public function gc_temp()
    {
        $tmp = unslashify($this->config->get('temp_dir'));

        // expire in 48 hours by default
        $temp_dir_ttl = $this->config->get('temp_dir_ttl', '48h');
        $temp_dir_ttl = get_offset_sec($temp_dir_ttl);
        if ($temp_dir_ttl < 6 * 3600) {
            $temp_dir_ttl = 6 * 3600;   // 6 hours sensible lower bound.
        }

        // Uploaded files metadata
        $db = $this->get_dbh();
        $db->query('DELETE FROM ' . $db->table_name('uploads', true)
            . ' WHERE `created` < ' . $db->now($temp_dir_ttl * -1));

        $expire = time() - $temp_dir_ttl;

        if ($tmp && ($dir = opendir($tmp))) {
            while (($fname = readdir($dir)) !== false) {
                if (strpos($fname, RCUBE_TEMP_FILE_PREFIX) !== 0) {
                    continue;
                }

                if (@filemtime("{$tmp}/{$fname}") < $expire) {
                    @unlink("{$tmp}/{$fname}");
                }
            }

            closedir($dir);
        }
    }

    /**
     * Runs garbage collector with probability based on
     * session settings. This is intended for environments
     * without a session.
     */
    public function gc_run()
    {
        $probability = (int) ini_get('session.gc_probability');
        $divisor = (int) ini_get('session.gc_divisor');

        if ($divisor > 0 && $probability > 0) {
            $random = mt_rand(1, $divisor);
            if ($random <= $probability) {
                $this->gc();
            }
        }
    }

    /**
     * Get localized text in the desired language
     *
     * @param mixed  $attrib Named parameters array or label name
     * @param string $domain Label domain (plugin) name
     *
     * @return string Localized text
     */
    public function gettext($attrib, $domain = null)
    {
        // load localization files if not done yet
        if (empty($this->texts)) {
            $this->load_language();
        }

        // extract attributes
        if (is_string($attrib)) {
            $attrib = ['name' => $attrib];
        }

        $name = (string) $attrib['name'];

        // attrib contain text values: use them from now
        $slang = !empty($_SESSION['language']) ? strtolower($_SESSION['language']) : 'en_us';
        if (isset($attrib[$slang])) {
            $this->texts[$name] = $attrib[$slang];
        } elseif ($slang != 'en_us' && isset($attrib['en_us'])) {
            $this->texts[$name] = $attrib['en_us'];
        }

        // check for text with domain
        if ($domain && isset($this->texts["{$domain}.{$name}"])) {
            $text = $this->texts["{$domain}.{$name}"];
        } elseif (isset($this->texts[$name])) {
            $text = $this->texts[$name];
        }

        // text does not exist
        if (!isset($text)) {
            return "[{$name}]";
        }

        // replace vars in text
        if (!empty($attrib['vars']) && is_array($attrib['vars'])) {
            foreach ($attrib['vars'] as $var_key => $var_value) {
                if ($var_key[0] != '$') {
                    $var_key = '$' . $var_key;
                }

                $text = str_replace($var_key, $var_value ?? '', $text);
            }
        }

        // replace \n with real line break
        $text = strtr($text, ['\n' => "\n"]);

        // case folding
        if ((!empty($attrib['uppercase']) && strtolower($attrib['uppercase']) == 'first') || !empty($attrib['ucfirst'])) {
            $case_mode = \MB_CASE_TITLE;
        } elseif (!empty($attrib['uppercase'])) {
            $case_mode = \MB_CASE_UPPER;
        } elseif (!empty($attrib['lowercase'])) {
            $case_mode = \MB_CASE_LOWER;
        }

        if (isset($case_mode)) {
            $text = mb_convert_case($text, $case_mode);
        }

        return $text;
    }

    /**
     * Check if the given text label exists
     *
     * @param string $name        Label name
     * @param string $domain      Label domain (plugin) name or '*' for all domains
     * @param string &$ref_domain Sets domain name if label is found
     *
     * @return bool True if text exists (either in the current language or in en_US)
     */
    public function text_exists($name, $domain = null, &$ref_domain = null)
    {
        // load localization files if not done yet
        if (empty($this->texts)) {
            $this->load_language();
        }

        if (isset($this->texts[$name])) {
            $ref_domain = '';
            return true;
        }

        // any of loaded domains (plugins)
        if ($domain == '*') {
            foreach ($this->plugins->loaded_plugins() as $domain2) {
                if (isset($this->texts[$domain2 . '.' . $name])) {
                    $ref_domain = $domain2;
                    return true;
                }
            }
        }
        // specified domain
        elseif ($domain && isset($this->texts[$domain . '.' . $name])) {
            $ref_domain = $domain;
            return true;
        }

        return false;
    }

    /**
     * Load a localization package
     *
     * @param string $lang  Language ID
     * @param array  $add   Additional text labels/messages
     * @param array  $merge Additional text labels/messages to merge
     */
    public function load_language($lang = null, $add = [], $merge = [])
    {
        $sess_lang = !empty($_SESSION['language']) ? $_SESSION['language'] : 'en_US';
        $lang = $this->language_prop($lang ?: $sess_lang);

        // load localized texts
        if (empty($this->texts) || $lang != $sess_lang) {
            // get english labels (these should be complete)
            $files = [
                RCUBE_LOCALIZATION_DIR . 'en_US/labels.inc',
                RCUBE_LOCALIZATION_DIR . 'en_US/messages.inc',
            ];

            // include user language files
            if ($lang != 'en' && $lang != 'en_US' && is_dir(RCUBE_LOCALIZATION_DIR . $lang)) {
                $files[] = RCUBE_LOCALIZATION_DIR . $lang . '/labels.inc';
                $files[] = RCUBE_LOCALIZATION_DIR . $lang . '/messages.inc';
            }

            $this->texts = [];

            foreach ($files as $file) {
                $this->texts = self::read_localization_file($file, $this->texts);
            }

            $_SESSION['language'] = $lang;
        }

        // append additional texts (from plugin)
        if (!empty($add)) {
            $this->texts += $add;
        }

        // merge additional texts (from plugin)
        if (!empty($merge)) {
            $this->texts = array_merge($this->texts, $merge);
        }
    }

    /**
     * Read localized texts from an additional location (plugins, skins).
     * Then you can use the result as 2nd arg to load_language().
     *
     * @param string      $dir  Directory to search in
     * @param string|null $lang Language code to read
     *
     * @return array Localization labels/messages
     */
    public function read_localization($dir, $lang = null)
    {
        if (empty($lang)) {
            $lang = $_SESSION['language'] ?? 'en_US';
        }
        $langs = array_unique(['en_US', $lang]);
        $locdir = slashify($dir);
        $texts = [];

        // Language aliases used to find localization in similar lang, see below
        $aliases = [
            'de_CH' => 'de_DE',
            'es_AR' => 'es_ES',
            'fa_AF' => 'fa_IR',
            'nl_BE' => 'nl_NL',
            'pt_BR' => 'pt_PT',
            'zh_CN' => 'zh_TW',
        ];

        foreach ($langs as $lng) {
            $fpath = $locdir . $lng . '.inc';
            $_texts = self::read_localization_file($fpath);

            if (!empty($_texts)) {
                $texts = array_merge($texts, $_texts);
            }
            // Fallback to a localization in similar language (#1488401)
            elseif ($lng != 'en_US') {
                $alias = null;
                if (!empty($aliases[$lng])) {
                    $alias = $aliases[$lng];
                } elseif ($key = array_search($lng, $aliases)) {
                    $alias = $key;
                }

                if (!empty($alias)) {
                    $fpath = $locdir . $alias . '.inc';
                    $texts = self::read_localization_file($fpath, $texts);
                }
            }
        }

        return $texts;
    }

    /**
     * Load localization file
     *
     * @param string $file  File location
     * @param array  $texts Additional texts to merge with
     *
     * @return array Localization labels/messages
     */
    public static function read_localization_file($file, $texts = [])
    {
        if (is_file($file) && is_readable($file)) {
            $labels = [];
            $messages = [];

            // use buffering to handle empty lines/spaces after closing PHP tag
            ob_start();
            require $file;
            ob_end_clean();

            // @phpstan-ignore-next-line
            if (!empty($labels)) {
                $texts = array_merge($texts, $labels);
            }

            // @phpstan-ignore-next-line
            if (!empty($messages)) {
                $texts = array_merge($texts, $messages);
            }
        }

        return $texts;
    }

    /**
     * Check the given string and return a valid language code
     *
     * @param string $lang Language code
     *
     * @return string Valid language code
     */
    protected function language_prop($lang)
    {
        static $rcube_languages, $rcube_language_aliases;

        // user HTTP_ACCEPT_LANGUAGE if no language is specified
        if ((empty($lang) || $lang == 'auto') && !empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
            $accept_langs = explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']);
            $lang = $accept_langs[0];

            if (preg_match('/^([a-z]+)[_-]([a-z0-9]+)$/i', $lang, $m)) {
                $lang = $m[1] . '_' . strtoupper($m[2]);
            }
        }

        if (empty($rcube_languages)) {
            @include RCUBE_LOCALIZATION_DIR . 'index.inc';
        }

        // check if we have an alias for that language
        if (!isset($rcube_languages[$lang]) && isset($rcube_language_aliases[$lang])) {
            $lang = $rcube_language_aliases[$lang];
        }
        // try the first two chars
        elseif ($lang && !isset($rcube_languages[$lang])) {
            $short = substr($lang, 0, 2);

            // check if we have an alias for the short language code
            if (!isset($rcube_languages[$short]) && isset($rcube_language_aliases[$short])) {
                $lang = $rcube_language_aliases[$short];
            }
            // expand 'nn' to 'nn_NN'
            elseif (!isset($rcube_languages[$short])) {
                $lang = $short . '_' . strtoupper($short);
            }
        }

        if (!isset($rcube_languages[$lang]) || !is_dir(RCUBE_LOCALIZATION_DIR . $lang)) {
            $lang = 'en_US';
        }

        return $lang;
    }

    /**
     * Read directory program/localization and return a list of available languages
     *
     * @return array List of available localizations
     */
    public function list_languages()
    {
        static $sa_languages = [];

        if (!count($sa_languages)) {
            @include RCUBE_LOCALIZATION_DIR . 'index.inc';

            if ($dh = @opendir(RCUBE_LOCALIZATION_DIR)) {
                while (($name = readdir($dh)) !== false) {
                    if ($name[0] == '.' || !is_dir(RCUBE_LOCALIZATION_DIR . $name)) {
                        continue;
                    }

                    if (isset($rcube_languages[$name])) {
                        $sa_languages[$name] = $rcube_languages[$name];
                    }
                }

                closedir($dh);
            }
        }

        return $sa_languages;
    }

    /**
     * Encrypt a string
     *
     * @param string $clear  Clear text input
     * @param string $key    Encryption key to retrieve from the configuration, defaults to 'des_key'
     * @param bool   $base64 Whether or not to base64_encode() the result before returning
     *
     * @return string|false Encrypted text, false on error
     */
    public function encrypt($clear, $key = 'des_key', $base64 = true)
    {
        // @phpstan-ignore-next-line
        if (!is_string($clear) || !strlen($clear)) {
            return '';
        }

        $ckey = $this->config->get_crypto_key($key);
        $method = $this->config->get_crypto_method();
        $iv = rcube_utils::random_bytes(openssl_cipher_iv_length($method), true);
        $tag = null;

        // This distinction is for PHP 7.3 which throws a warning when
        // we use $tag argument with non-AEAD cipher method here
        if (!preg_match('/-(gcm|ccm|poly1305)$/i', $method)) {
            $cipher = openssl_encrypt($clear, $method, $ckey, \OPENSSL_RAW_DATA, $iv);
        } else {
            $cipher = openssl_encrypt($clear, $method, $ckey, \OPENSSL_RAW_DATA, $iv, $tag);
        }

        if ($cipher === false) {
            self::raise_error("Failed to encrypt data with configured cipher method: {$method}!", true);
            return false;
        }

        $cipher = $iv . $cipher;

        if ($tag !== null) {
            $cipher = "##{$tag}##{$cipher}";
        }

        return $base64 ? base64_encode($cipher) : $cipher;
    }

    /**
     * Decrypt a string
     *
     * @param string $cipher Encrypted text
     * @param string $key    Encryption key to retrieve from the configuration, defaults to 'des_key'
     * @param bool   $base64 Whether or not input is base64-encoded
     *
     * @return string|false Decrypted text, false on error
     */
    public function decrypt($cipher, $key = 'des_key', $base64 = true)
    {
        // @phpstan-ignore-next-line
        if (!is_string($cipher) || !strlen($cipher)) {
            return false;
        }

        if ($base64) {
            $cipher = base64_decode($cipher, true);
            if ($cipher === false) {
                return false;
            }
        }

        $ckey = $this->config->get_crypto_key($key);
        $method = $this->config->get_crypto_method();
        $iv_size = openssl_cipher_iv_length($method);
        $tag = null;

        if (preg_match('/^##(.{16})##/s', $cipher, $matches)) {
            $tag = $matches[1];
            $cipher = substr($cipher, strlen($matches[0]));
        }

        $iv = substr($cipher, 0, $iv_size);

        // session corruption? (#1485970)
        if (strlen($iv) < $iv_size) {
            return false;
        }

        $cipher = substr($cipher, $iv_size);
        $clear = openssl_decrypt($cipher, $method, $ckey, \OPENSSL_RAW_DATA, $iv, $tag);

        return $clear;
    }

    /**
     * Returns session token for secure URLs
     *
     * @param bool $generate Generate token if not exists in session yet
     *
     * @return string|bool Token string, False when disabled
     */
    public function get_secure_url_token($generate = false)
    {
        if ($len = $this->config->get('use_secure_urls')) {
            if (empty($_SESSION['secure_token']) && $generate) {
                // generate x characters long token
                $length = $len > 1 ? $len : 16;
                $token = rcube_utils::random_bytes($length);

                $plugin = $this->plugins->exec_hook('secure_token', ['value' => $token, 'length' => $length]);

                $_SESSION['secure_token'] = $plugin['value'];
            }

            if (!empty($_SESSION['secure_token'])) {
                return $_SESSION['secure_token'];
            }
        }

        return false;
    }

    /**
     * Generate a unique token to be used in a form request
     *
     * @return string The request token
     */
    public function get_request_token()
    {
        if (empty($_SESSION['request_token'])) {
            $plugin = $this->plugins->exec_hook('request_token', ['value' => rcube_utils::random_bytes(32)]);

            $_SESSION['request_token'] = $plugin['value'];
        }

        return $_SESSION['request_token'];
    }

    /**
     * Check if the current request contains a valid token.
     * Empty requests aren't checked until use_secure_urls is set.
     *
     * @param int $mode Request method
     *
     * @return bool True if request token is valid false if not
     */
    public function check_request($mode = rcube_utils::INPUT_POST)
    {
        // check secure token in URL if enabled
        if ($token = $this->get_secure_url_token()) {
            foreach (explode('/', preg_replace('/[?#&].*$/', '', $_SERVER['REQUEST_URI'])) as $tok) {
                if ($tok == $token) {
                    return true;
                }
            }

            $this->request_status = self::REQUEST_ERROR_URL;

            return false;
        }

        $sess_tok = $this->get_request_token();

        // ajax requests
        if (rcube_utils::request_header('X-Roundcube-Request') === $sess_tok) {
            return true;
        }

        // skip empty requests
        if (($mode == rcube_utils::INPUT_POST && empty($_POST))
            || ($mode == rcube_utils::INPUT_GET && empty($_GET))
        ) {
            return true;
        }

        // default method of securing requests
        $token = rcube_utils::get_input_value('_token', $mode);

        if (empty($_COOKIE[ini_get('session.name')]) || $token !== $sess_tok) {
            $this->request_status = self::REQUEST_ERROR_TOKEN;
            return false;
        }

        return true;
    }

    /**
     * Build a valid URL to this instance of Roundcube.
     *
     * @param mixed $p        Either a string with the action or
     *                        url parameters as key-value pairs
     * @param bool  $absolute Build a URL absolute to document root
     * @param bool  $full     Create fully qualified URL including http(s):// and hostname
     * @param bool  $secure   Return absolute URL in secure location
     *
     * @return string Valid application URL
     */
    public function url($p, $absolute = false, $full = false, $secure = false)
    {
        // STUB: should be overloaded by the application
        return '';
    }

    /**
     * Function to be executed in script shutdown
     * Registered with register_shutdown_function()
     */
    public function shutdown()
    {
        foreach ($this->shutdown_functions as $function) {
            call_user_func($function);
        }

        // write session data as soon as possible and before
        // closing database connection, don't do this before
        // registered shutdown functions, they may need the session
        // Note: this will run registered gc handlers (ie. cache gc)
        if (!empty($_SERVER['REMOTE_ADDR']) && is_object($this->session)) {
            $this->session->write_close();
        }

        if (is_object($this->smtp)) {
            $this->smtp->disconnect();
        }

        foreach ($this->caches as $cache) {
            if ($cache) {
                $cache->close();
            }
        }

        if (is_object($this->storage)) {
            $this->storage->close();
        }

        if ($this->config->get('log_driver') == 'syslog') {
            closelog();
        }
    }

    /**
     * Registers shutdown function to be executed on shutdown.
     * The functions will be executed before destroying any
     * objects like smtp, imap, session, etc.
     *
     * @param callable $function Function callback
     */
    public function add_shutdown_function($function)
    {
        $this->shutdown_functions[] = $function;
    }

    /**
     * When you're going to sleep the script execution for a longer time
     * it is good to close all external connections (sql, memcache, redis, SMTP, IMAP).
     *
     * No action is required on wake up, all connections will be
     * re-established automatically.
     */
    public function sleep()
    {
        foreach ($this->caches as $cache) {
            if ($cache) {
                $cache->close();
            }
        }

        if ($this->storage) {
            $this->storage->close();
        }

        if ($this->db) {
            $this->db->closeConnection();
        }

        if ($this->memcache) {
            $this->memcache->close();
        }

        if ($this->memcached) {
            $this->memcached->quit();
        }

        if ($this->smtp) {
            $this->smtp->disconnect();
        }

        if ($this->redis) {
            $this->redis->close();
        }
    }

    /**
     * Quote a given string.
     * Shortcut function for rcube_utils::rep_specialchars_output()
     *
     * @param string $str      A string to quote
     * @param string $mode     Replace mode for tags: show|remove|strict
     * @param bool   $newlines Convert newlines
     *
     * @return string HTML-quoted string
     */
    public static function Q($str, $mode = 'strict', $newlines = true)
    {
        return rcube_utils::rep_specialchars_output($str, 'html', $mode, $newlines);
    }

    /**
     * Quote a given string for javascript output.
     * Shortcut function for rcube_utils::rep_specialchars_output()
     *
     * @param string $str A string to quote
     *
     * @return string JS-quoted string
     */
    public static function JQ($str)
    {
        return rcube_utils::rep_specialchars_output($str, 'js');
    }

    /**
     * Quote a given string, remove new-line characters, use strict mode.
     * Shortcut function for rcube_utils::rep_specialchars_output()
     *
     * @param string $str A string to quote
     *
     * @return string HTML-quoted string
     */
    public static function SQ($str)
    {
        return rcube_utils::rep_specialchars_output($str, 'html', 'strict', false);
    }

    /**
     * Construct shell command, execute it and return output as string.
     * Keywords {keyword} are replaced with arguments
     *
     * @param string $cmd     Format string with {keywords} to be replaced
     * @param mixed  ...$args (zero, one or more arrays can be passed)
     *
     * @return string Output of command. Shell errors not detectable
     */
    public static function exec($cmd, ...$args)
    {
        $values = $replacements = [];

        // merge values into one array
        foreach ($args as $arg) {
            $values += (array) $arg;
        }

        preg_match_all('/({(-?)([a-z]\w*)})/', $cmd, $matches, \PREG_SET_ORDER);
        foreach ($matches as $tags) {
            [, $tag, $option, $optkey] = $tags;
            $parts = [];

            if ($option) {
                foreach ((array) $values["-{$optkey}"] as $key => $value) {
                    if ($value === true || $value === false || $value === null) {
                        $parts[] = $value ? $key : '';
                    } else {
                        foreach ((array) $value as $val) {
                            $parts[] = "{$key} " . escapeshellarg($val);
                        }
                    }
                }
            } else {
                foreach ((array) $values[$optkey] as $value) {
                    $parts[] = escapeshellarg($value);
                }
            }

            $replacements[$tag] = implode(' ', $parts);
        }

        // use strtr behaviour of going through source string once
        $cmd = strtr($cmd, $replacements);

        return (string) shell_exec($cmd);
    }

    /**
     * Print or write debug messages
     *
     * @param mixed ...$args Debug message or data
     */
    public static function console(...$args)
    {
        if (class_exists('rcube', false)) {
            $rcube = self::get_instance();
            $plugin = $rcube->plugins->exec_hook('console', ['args' => $args]);
            if (!empty($plugin['abort'])) {
                return;
            }

            $args = $plugin['args'];
        }

        $msg = [];
        foreach ($args as $arg) {
            $msg[] = !is_string($arg) ? var_export($arg, true) : $arg;
        }

        self::write_log('console', implode(";\n", $msg));
    }

    /**
     * Append a line to a logfile in the logs directory.
     * Date will be added automatically to the line.
     *
     * @param string $name Name of the log file
     * @param mixed  $line Line to append
     *
     * @return bool True on success, False on failure
     */
    public static function write_log($name, $line)
    {
        if (!is_string($line)) {
            $line = var_export($line, true);
        }

        $date_format = $log_driver = $session_key = null;
        if (self::$instance) {
            $date_format = self::$instance->config->get('log_date_format');
            $log_driver = self::$instance->config->get('log_driver');
            $session_key = intval(self::$instance->config->get('log_session_id', 8));
        }

        $date = rcube_utils::date_format($date_format);

        // trigger logging hook
        if (self::$instance) {
            $log = self::$instance->plugins->exec_hook('write_log',
                ['name' => $name, 'date' => $date, 'line' => $line]
            );

            $name = $log['name'];
            $line = $log['line'];
            $date = $log['date'];

            if (!empty($log['abort'])) {
                return true;
            }
        }

        // add session ID to the log
        if ($session_key > 0 && ($sess = session_id())) {
            $line = '<' . substr($sess, 0, $session_key) . '> ' . $line;
        }

        if ($log_driver == 'syslog') {
            $prio = $name == 'errors' ? \LOG_ERR : \LOG_INFO;
            return syslog($prio, $line);
        }

        // write message with file name when configured to log to STDOUT
        if ($log_driver == 'stdout') {
            $stdout = 'php://stdout';
            $line = "{$name}: {$line}\n";
            return file_put_contents($stdout, $line, \FILE_APPEND) !== false;
        }

        // write to php's configured error_log (or that which is configured in .htaccess)
        if ($log_driver == 'php') {
            $line = "{$name}: {$line}";
            return error_log($line);
        }

        // log_driver == 'file' is assumed here

        $line = sprintf("[%s]: %s\n", $date, $line);

        // per-user logging is activated
        if (self::$instance && self::$instance->config->get('per_user_logging')
            && !in_array($name, ['userlogins', 'sendmail'])
        ) {
            $log_dir = self::$instance->get_user_log_dir();
            if (empty($log_dir) && $name !== 'errors') {
                return false;
            }
        }

        if (empty($log_dir)) {
            if (!empty($log['dir'])) {
                $log_dir = $log['dir'];
            } elseif (self::$instance) {
                $log_dir = self::$instance->config->get('log_dir');
            }
        }

        if (empty($log_dir)) {
            $log_dir = RCUBE_INSTALL_PATH . 'logs';
        }

        if (self::$instance) {
            $name .= self::$instance->config->get('log_file_ext', '.log');
        } else {
            $name .= '.log';
        }

        return file_put_contents("{$log_dir}/{$name}", $line, \FILE_APPEND) !== false;
    }

    /**
     * Throw system error, with optional logging and script termination.
     *
     * @param int|array|Throwable|string|PEAR_Error $arg       Error object, int, string or named parameters array:
     *                                                         - code:    Error code (required)
     *                                                         - type:    Error type: php, db, imap, etc.
     *                                                         - message: Error message
     *                                                         - file:    File where error occurred
     *                                                         - line:    Line where error occurred
     * @param bool                                  $log       True to log the error
     * @param bool                                  $terminate Terminate script execution
     */
    public static function raise_error($arg, $log = false, $terminate = false)
    {
        // handle PHP exceptions and errors
        if ($arg instanceof Throwable) {
            $arg = [
                'code' => $arg->getCode(),
                'line' => $arg->getLine(),
                'file' => $arg->getFile(),
                'message' => $arg->getMessage(),
            ];
        } elseif (is_object($arg) && is_a($arg, 'PEAR_Error')) {
            $info = $arg->getUserInfo();
            $arg = [
                'code' => $arg->getCode(),
                'message' => $arg->getMessage() . ($info ? ': ' . $info : ''),
            ];
        } elseif (is_int($arg)) {
            $arg = ['code' => $arg];
        } elseif (is_string($arg)) {
            $arg = ['message' => $arg];
        }

        if (empty($arg['code'])) {
            $arg['code'] = 500;
        }

        $prevStackFrame = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS, 1)[0];
        if (
            !isset($arg['file']) && isset($prevStackFrame['file'])
            && !isset($arg['line']) && isset($prevStackFrame['line'])
        ) {
            $arg['file'] = $prevStackFrame['file'];
            $arg['line'] = $prevStackFrame['line'];
        }

        $cli = \PHP_SAPI == 'cli';

        $arg['cli'] = $cli;
        $arg['log'] = $log;
        $arg['terminate'] = $terminate;

        // send error to external error tracking tool
        if (self::$instance) {
            $arg = self::$instance->plugins->exec_hook('raise_error', $arg);
        }

        // installer
        if (!$cli && class_exists('rcmail_install', false)) {
            $rci = rcmail_install::get_instance();
            $rci->raise_error($arg);
            return;
        }

        if (!isset($arg['message'])) {
            $arg['message'] = '';
        }

        if (($log || $terminate) && !$cli && $arg['message']) {
            $arg['fatal'] = $terminate;
            self::log_bug($arg);
        }

        if ($cli) {
            fwrite(\STDERR, 'ERROR: ' . trim($arg['message']) . "\n");
        } elseif ($terminate && self::$instance && is_object(self::$instance->output)) {
            self::$instance->output->raise_error($arg['code'], $arg['message']);
        } elseif ($terminate) {
            http_response_code(500);
        }

        // terminate script
        if ($terminate) {
            if (defined('ROUNDCUBE_TEST_MODE')) {
                throw new Exception('Error raised');
            }

            exit(1);
        }
    }

    /**
     * Log an error
     *
     * @param array $arg_arr Named parameters
     *
     * @see self::raise_error()
     */
    public static function log_bug($arg_arr)
    {
        $program = !empty($arg_arr['type']) ? strtoupper($arg_arr['type']) : 'PHP';
        $uri = $_SERVER['REQUEST_URI'] ?? '';

        // write error to local log file
        if ($_SERVER['REQUEST_METHOD'] == 'POST') {
            $post_query = [];
            foreach (['_task', '_action'] as $arg) {
                if (isset($_POST[$arg]) && !isset($_GET[$arg])) {
                    $post_query[$arg] = $_POST[$arg];
                }
            }

            if (!empty($post_query)) {
                $uri .= (strpos($uri, '?') != false ? '&' : '?')
                    . http_build_query($post_query, '', '&');
            }
        }

        $log_entry = sprintf('%s Error: %s%s (%s %s)',
            $program,
            $arg_arr['message'],
            !empty($arg_arr['file']) ? sprintf(' in %s on line %d', $arg_arr['file'], $arg_arr['line']) : '',
            $_SERVER['REQUEST_METHOD'],
            strip_tags($uri)
        );

        if (!self::write_log('errors', $log_entry)) {
            // send error to PHPs error handler if write_log didn't succeed
            trigger_error($arg_arr['message'], \E_USER_WARNING);
        }
    }

    /**
     * Write debug info to the log
     *
     * @param string $engine Engine type - file name (memcache, apc, redis)
     * @param string $data   Data string to log
     * @param bool   $result Operation result
     */
    public static function debug($engine, $data, $result = null)
    {
        static $debug_counter;

        $line = '[' . (++$debug_counter[$engine]) . '] ' . $data;

        if (($len = strlen($line)) > self::DEBUG_LINE_LENGTH) {
            $diff = $len - self::DEBUG_LINE_LENGTH;
            $line = substr($line, 0, self::DEBUG_LINE_LENGTH) . "... [truncated {$diff} bytes]";
        }

        if ($result !== null) {
            $line .= ' [' . ($result ? 'TRUE' : 'FALSE') . ']';
        }

        self::write_log($engine, $line);
    }

    /**
     * Returns current time (with microseconds).
     *
     * @return float Current time in seconds since the Unix
     */
    public static function timer()
    {
        return microtime(true);
    }

    /**
     * Logs time difference according to provided timer
     *
     * @param float  $timer Timer (self::timer() result)
     * @param string $label Log line prefix
     * @param string $dest  Log file name
     *
     * @see self::timer()
     */
    public static function print_timer($timer, $label = 'Timer', $dest = 'console')
    {
        static $print_count = 0;

        $print_count++;
        $now = self::timer();
        $diff = $now - $timer;

        if (empty($label)) {
            $label = 'Timer ' . $print_count;
        }

        self::write_log($dest, sprintf('%s: %0.4f sec', $label, $diff));
    }

    /**
     * Getter for session identifier.
     *
     * @return string Session ID
     */
    public function get_session_id()
    {
        return defined('ROUNDCUBE_TEST_SESSION') ? ROUNDCUBE_TEST_SESSION : session_id();
    }

    /**
     * Setter for system user object
     *
     * @param rcube_user $user Current user instance
     */
    public function set_user($user)
    {
        // @phpstan-ignore-next-line
        if (is_object($user)) {
            $this->user = $user;

            // overwrite config with user preferences
            $this->config->set_user_prefs((array) $this->user->get_prefs());
        }
    }

    /**
     * Getter for logged user ID.
     *
     * @return int|null User identifier
     */
    public function get_user_id()
    {
        if (is_object($this->user)) {
            return (int) $this->user->ID;
        }

        if (isset($_SESSION['user_id'])) {
            return (int) $_SESSION['user_id'];
        }

        return null;
    }

    /**
     * Getter for logged user name.
     *
     * @return string|null User name
     */
    public function get_user_name()
    {
        if (is_object($this->user)) {
            return $this->user->get_username();
        }

        if (isset($_SESSION['username'])) {
            return $_SESSION['username'];
        }

        return null;
    }

    /**
     * Getter for logged user email (derived from user name not identity).
     *
     * @return string|null User email address
     */
    public function get_user_email()
    {
        if (!empty($this->user_email)) {
            return $this->user_email;
        }

        if (is_object($this->user)) {
            return $this->user->get_username('mail');
        }

        return null;
    }

    /**
     * Getter for logged user password.
     *
     * @return string|null User password
     */
    public function get_user_password()
    {
        if (!empty($this->password)) {
            return $this->password;
        }

        if (isset($_SESSION['password'])) {
            return $this->decrypt($_SESSION['password']);
        }

        return null;
    }

    /**
     * Get the per-user log directory
     *
     * @return string|false Per-user log directory if it exists and is writable, False otherwise
     */
    protected function get_user_log_dir()
    {
        $log_dir = $this->config->get('log_dir', RCUBE_INSTALL_PATH . 'logs');
        $user_name = $this->get_user_name();
        $user_log_dir = $log_dir . '/' . $user_name;

        return !empty($user_name) && is_writable($user_log_dir) ? $user_log_dir : false;
    }

    /**
     * Getter for logged user language code.
     *
     * @return string|null User language code
     */
    public function get_user_language()
    {
        if (is_object($this->user)) {
            return $this->user->language;
        }

        if (isset($_SESSION['language'])) {
            return $_SESSION['language'];
        }

        return null;
    }

    /**
     * Unique Message-ID generator.
     *
     * @param string $sender Optional sender e-mail address
     *
     * @return string Message-ID
     */
    public function gen_message_id($sender = null)
    {
        $local_part = md5(uniqid('rcube' . mt_rand(), true));
        $domain_part = '';

        if ($sender && preg_match('/@([^\s]+\.[a-z0-9-]+)/', $sender, $m)) {
            $domain_part = $m[1];
        } else {
            $domain_part = $this->user->get_username('domain');
        }

        // Try to find FQDN, some spamfilters doesn't like 'localhost' (#1486924)
        if (!preg_match('/\.[a-z0-9-]+$/i', $domain_part)) {
            foreach ([$_SERVER['HTTP_HOST'], $_SERVER['SERVER_NAME']] as $host) {
                $host = preg_replace('/:[0-9]+$/', '', $host);
                if ($host && preg_match('/\.[a-z]+$/i', $host)) {
                    $domain_part = $host;
                    break;
                }
            }
        }

        return sprintf('<%s@%s>', $local_part, $domain_part);
    }

    /**
     * Send the given message using the configured method.
     *
     * @param Mail_mime    $message    Reference to Mail_mime object
     * @param string       $from       Sender address string
     * @param array|string $mailto     Either a comma-separated list of recipients (RFC822 compliant),
     *                                 or an array of recipients, each RFC822 valid
     * @param array|string &$error     SMTP error array or (deprecated) string
     * @param string       &$body_file Location of file with saved message body,
     *                                 used when delay_file_io is enabled
     * @param array        $options    SMTP options (e.g. DSN request)
     * @param bool         $disconnect Close SMTP connection ASAP
     *
     * @return bool send status
     */
    public function deliver_message($message, $from, $mailto, &$error,
        &$body_file = null, $options = null, $disconnect = false)
    {
        $plugin = $this->plugins->exec_hook('message_before_send', [
            'message' => $message,
            'from' => $from,
            'mailto' => $mailto,
            'options' => $options,
        ]);

        if ($plugin['abort']) {
            if (!empty($plugin['error'])) {
                $error = $plugin['error'];
            }
            if (!empty($plugin['body_file'])) {
                $body_file = $plugin['body_file'];
            }

            return $plugin['result'] ?? false;
        }

        $from = $plugin['from'];
        $mailto = $plugin['mailto'];
        $options = $plugin['options'];
        $message = $plugin['message'];
        $headers = $message->headers();

        // generate list of recipients
        $a_recipients = (array) $mailto;

        if (!empty($headers['Cc'])) {
            $a_recipients[] = $headers['Cc'];
        }
        if (!empty($headers['Bcc'])) {
            $a_recipients[] = $headers['Bcc'];
        }

        // remove Bcc header and get the whole head of the message as string
        $smtp_headers = $message->txtHeaders(['Bcc' => null], true);

        if ($message->getParam('delay_file_io')) {
            // use common temp dir
            $body_file = rcube_utils::temp_filename('msg');
            $mime_result = $message->saveMessageBody($body_file);

            if (is_a($mime_result, 'PEAR_Error')) {
                self::raise_error([
                    'code' => 650,
                    'message' => 'Could not create message: ' . $mime_result->getMessage(),
                ], true, false);
                return false;
            }

            $msg_body = fopen($body_file, 'r');
        } else {
            $msg_body = $message->get();
        }

        // initialize SMTP connection
        if (!is_object($this->smtp)) {
            $this->smtp_init(true);
        }

        // send message
        $sent = $this->smtp->send_mail($from, $a_recipients, $smtp_headers, $msg_body, $options);
        $response = $this->smtp->get_response();
        $error = $this->smtp->get_error();

        if (!$sent) {
            self::raise_error([
                'code' => 800,
                'type' => 'smtp',
                'message' => implode("\n", $response),
            ], true, false);

            // allow plugins to catch sending errors with the same parameters as in 'message_before_send'
            $plugin = $this->plugins->exec_hook('message_send_error', $plugin + ['error' => $error]);
            $error = $plugin['error'];
        } else {
            $this->plugins->exec_hook('message_sent', ['headers' => $headers, 'body' => $msg_body, 'message' => $message]);

            // remove MDN/DSN headers after sending
            unset($headers['Return-Receipt-To'], $headers['Disposition-Notification-To']);

            if ($this->config->get('smtp_log')) {
                // get all recipient addresses
                $mailto = implode(',', $a_recipients);
                $mailto = rcube_mime::decode_address_list($mailto, null, false, null, true);

                self::write_log('sendmail', sprintf('User %s [%s]; Message %s for %s; %s',
                    $this->user->get_username(),
                    rcube_utils::remote_addr(),
                    $headers['Message-ID'],
                    implode(', ', $mailto),
                    !empty($response) ? implode('; ', $response) : '')
                );
            }
        }

        if (is_resource($msg_body)) {
            fclose($msg_body);
        }

        if ($disconnect) {
            $this->smtp->disconnect();
        }

        // Add Bcc header back
        if (!empty($headers['Bcc'])) {
            $message->headers(['Bcc' => $headers['Bcc']], true);
        }

        return $sent;
    }
}

/**
 * Lightweight plugin API class serving as a dummy if plugins are not enabled
 */
class rcube_dummy_plugin_api
{
    /**
     * Triggers a plugin hook.
     *
     * @param string       $hook Hook name
     * @param array|string $args Hook arguments
     *
     * @return array Hook arguments
     *
     * @see rcube_plugin_api::exec_hook()
     */
    public function exec_hook($hook, $args = [])
    {
        if (!is_array($args)) {
            $args = ['arg' => $args];
        }

        return $args += ['abort' => false];
    }
}