<?php

/**
 +-----------------------------------------------------------------------+
 | This file is part of the Roundcube Webmail client                     |
 | Copyright (C) 2006-2013, The Roundcube Dev Team                       |
 | Copyright (C) 2011-2013, 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:                                                              |
 |   Interface to an LDAP address directory                              |
 +-----------------------------------------------------------------------+
 | Author: Thomas Bruederli <roundcube@gmail.com>                        |
 |         Andreas Dick <andudi (at) gmx (dot) ch>                       |
 |         Aleksander Machniak <machniak@kolabsys.com>                   |
 +-----------------------------------------------------------------------+
*/

/**
 * Model class to access an LDAP address directory
 *
 * @package    Framework
 * @subpackage Addressbook
 */
class rcube_ldap extends rcube_addressbook
{
    // public properties
    public $primary_key = 'ID';
    public $groups      = false;
    public $readonly    = true;
    public $ready       = false;
    public $group_id    = 0;
    public $coltypes    = array();
    public $export_groups = false;

    // private properties
    protected $ldap;
    protected $formats  = array();
    protected $prop     = array();
    protected $fieldmap = array();
    protected $filter   = '';
    protected $sub_filter;
    protected $result;
    protected $ldap_result;
    protected $mail_domain = '';
    protected $debug       = false;

    /**
     * Group objectclass (lowercase) to member attribute mapping
     *
     * @var array
     */
    private $group_types = array(
        'group'                   => 'member',
        'groupofnames'            => 'member',
        'kolabgroupofnames'       => 'member',
        'groupofuniquenames'      => 'uniqueMember',
        'kolabgroupofuniquenames' => 'uniqueMember',
        'univentiongroup'         => 'uniqueMember',
        'groupofurls'             => null,
    );

    private $base_dn        = '';
    private $groups_base_dn = '';
    private $group_data;
    private $group_search_cache;
    private $cache;


    /**
    * Object constructor
    *
    * @param array   $p            LDAP connection properties
    * @param boolean $debug        Enables debug mode
    * @param string  $mail_domain  Current user mail domain name
    */
    function __construct($p, $debug = false, $mail_domain = null)
    {
        $this->prop = $p;

        $fetch_attributes = array('objectClass');

        // check if groups are configured
        if (is_array($p['groups']) && count($p['groups'])) {
            $this->groups = true;
            // set member field
            if (!empty($p['groups']['member_attr']))
                $this->prop['member_attr'] = strtolower($p['groups']['member_attr']);
            else if (empty($p['member_attr']))
                $this->prop['member_attr'] = 'member';
            // set default name attribute to cn
            if (empty($this->prop['groups']['name_attr']))
                $this->prop['groups']['name_attr'] = 'cn';
            if (empty($this->prop['groups']['scope']))
                $this->prop['groups']['scope'] = 'sub';
            // extend group objectclass => member attribute mapping
            if (!empty($this->prop['groups']['class_member_attr']))
                $this->group_types = array_merge($this->group_types, $this->prop['groups']['class_member_attr']);

            // add group name attrib to the list of attributes to be fetched
            $fetch_attributes[] = $this->prop['groups']['name_attr'];
        }
        if (is_array($p['group_filters'])) {
            $this->groups = $this->groups || count($p['group_filters']);

            foreach ($p['group_filters'] as $k => $group_filter) {
                // set default name attribute to cn
                if (empty($group_filter['name_attr']) && empty($this->prop['groups']['name_attr']))
                    $this->prop['group_filters'][$k]['name_attr'] = $group_filter['name_attr'] = 'cn';

                if ($group_filter['name_attr'])
                    $fetch_attributes[] = $group_filter['name_attr'];
            }
        }

        // fieldmap property is given
        if (is_array($p['fieldmap'])) {
            $p['fieldmap'] = array_filter($p['fieldmap']);
            foreach ($p['fieldmap'] as $rf => $lf)
                $this->fieldmap[$rf] = $this->_attr_name($lf);
        }
        else if (!empty($p)) {
            // read deprecated *_field properties to remain backwards compatible
            foreach ($p as $prop => $value)
                if (!empty($value) && preg_match('/^(.+)_field$/', $prop, $matches))
                    $this->fieldmap[$matches[1]] = $this->_attr_name($value);
        }

        // use fieldmap to advertise supported coltypes to the application
        foreach ($this->fieldmap as $colv => $lfv) {
            list($col, $type) = explode(':', $colv);
            $params           = explode(':', $lfv);

            $lf    = array_shift($params);
            $limit = 1;

            foreach ($params as $idx => $param) {
                // field format specification
                if (preg_match('/^(date)\[(.+)\]$/i', $param, $m)) {
                    $this->formats[$lf] = array('type' => strtolower($m[1]), 'format' => $m[2]);
                }
                // first argument is a limit
                else if ($idx === 0) {
                    if ($param == '*') $limit = null;
                    else               $limit = max(1, intval($param));
                }
                // second is a composite field separator
                else if ($idx === 1 && $param) {
                    $this->coltypes[$col]['serialized'][$type] = $param;
                }
            }

            if (!is_array($this->coltypes[$col])) {
                $subtypes = $type ? array($type) : null;
                $this->coltypes[$col] = array('limit' => $limit, 'subtypes' => $subtypes, 'attributes' => array($lf));
            }
            elseif ($type) {
                $this->coltypes[$col]['subtypes'][] = $type;
                $this->coltypes[$col]['attributes'][] = $lf;
                $this->coltypes[$col]['limit'] += $limit;
            }

            $this->fieldmap[$colv] = $lf;
        }

        // support for composite address
        if ($this->coltypes['street'] && $this->coltypes['locality']) {
            $this->coltypes['address'] = array(
               'limit'    => max(1, $this->coltypes['locality']['limit'] + $this->coltypes['address']['limit']),
               'subtypes' => array_merge((array)$this->coltypes['address']['subtypes'], (array)$this->coltypes['locality']['subtypes']),
               'childs' => array(),
               ) + (array)$this->coltypes['address'];

            foreach (array('street','locality','zipcode','region','country') as $childcol) {
                if ($this->coltypes[$childcol]) {
                    $this->coltypes['address']['childs'][$childcol] = array('type' => 'text');
                    unset($this->coltypes[$childcol]);  // remove address child col from global coltypes list
                }
            }

            // at least one address type must be specified
            if (empty($this->coltypes['address']['subtypes'])) {
                $this->coltypes['address']['subtypes'] = array('home');
            }
        }
        else if ($this->coltypes['address']) {
            $this->coltypes['address'] += array('type' => 'textarea', 'childs' => null, 'size' => 40);

            // 'serialized' means the UI has to present a composite address field
            if ($this->coltypes['address']['serialized']) {
                $childprop = array('type' => 'text');
                $this->coltypes['address']['type'] = 'composite';
                $this->coltypes['address']['childs'] = array('street' => $childprop, 'locality' => $childprop, 'zipcode' => $childprop, 'country' => $childprop);
            }
        }

        // make sure 'required_fields' is an array
        if (!is_array($this->prop['required_fields'])) {
            $this->prop['required_fields'] = (array) $this->prop['required_fields'];
        }

        // make sure LDAP_rdn field is required
        if (!empty($this->prop['LDAP_rdn']) && !in_array($this->prop['LDAP_rdn'], $this->prop['required_fields'])
            && !in_array($this->prop['LDAP_rdn'], array_keys((array)$this->prop['autovalues']))) {
            $this->prop['required_fields'][] = $this->prop['LDAP_rdn'];
        }

        foreach ($this->prop['required_fields'] as $key => $val) {
            $this->prop['required_fields'][$key] = $this->_attr_name($val);
        }

        // Build sub_fields filter
        if (!empty($this->prop['sub_fields']) && is_array($this->prop['sub_fields'])) {
            $this->sub_filter = '';
            foreach ($this->prop['sub_fields'] as $class) {
                if (!empty($class)) {
                    $class = is_array($class) ? array_pop($class) : $class;
                    $this->sub_filter .= '(objectClass=' . $class . ')';
                }
            }
            if (count($this->prop['sub_fields']) > 1) {
                $this->sub_filter = '(|' . $this->sub_filter . ')';
            }
        }

        $this->sort_col    = is_array($p['sort']) ? $p['sort'][0] : $p['sort'];
        $this->debug       = $debug;
        $this->mail_domain = $mail_domain;

        // initialize cache
        $rcube = rcube::get_instance();
        if ($cache_type = $rcube->config->get('ldap_cache', 'db')) {
            $cache_ttl  = $rcube->config->get('ldap_cache_ttl', '10m');
            $cache_name = 'LDAP.' . asciiwords($this->prop['name']);

            $this->cache = $rcube->get_cache($cache_name, $cache_type, $cache_ttl);
        }

        // determine which attributes to fetch
        $this->prop['list_attributes'] = array_unique($fetch_attributes);
        $this->prop['attributes'] = array_merge(array_values($this->fieldmap), $fetch_attributes);
        foreach ($rcube->config->get('contactlist_fields') as $col) {
            $this->prop['list_attributes'] = array_merge($this->prop['list_attributes'], $this->_map_field($col));
        }

        // initialize ldap wrapper object
        $this->ldap = new rcube_ldap_generic($this->prop);
        $this->ldap->config_set(array('cache' => $this->cache, 'debug' => $this->debug));

        $this->_connect();
    }

    /**
     * Establish a connection to the LDAP server
     */
    private function _connect()
    {
        $rcube = rcube::get_instance();

        if ($this->ready)
            return true;

        if (!is_array($this->prop['hosts']))
            $this->prop['hosts'] = array($this->prop['hosts']);

        // try to connect + bind for every host configured
        // with OpenLDAP 2.x ldap_connect() always succeeds but ldap_bind will fail if host isn't reachable
        // see http://www.php.net/manual/en/function.ldap-connect.php
        foreach ($this->prop['hosts'] as $host) {
            // skip host if connection failed
            if (!$this->ldap->connect($host)) {
                continue;
            }

            // See if the directory is writeable.
            if ($this->prop['writable']) {
                $this->readonly = false;
            }

            $bind_pass = $this->prop['bind_pass'];
            $bind_user = $this->prop['bind_user'];
            $bind_dn   = $this->prop['bind_dn'];

            $this->base_dn        = $this->prop['base_dn'];
            $this->groups_base_dn = $this->prop['groups']['base_dn'] ?: $this->base_dn;

            // User specific access, generate the proper values to use.
            if ($this->prop['user_specific']) {
                // No password set, use the session password
                if (empty($bind_pass)) {
                    $bind_pass = $rcube->get_user_password();
                }

                // Get the pieces needed for variable replacement.
                if ($fu = $rcube->get_user_email()) {
                    list($u, $d) = explode('@', $fu);
                }
                else {
                    $d = $this->mail_domain;
                }

                $dc = 'dc='.strtr($d, array('.' => ',dc=')); // hierarchal domain string

                // resolve $dc through LDAP
                if (!empty($this->prop['domain_filter']) && !empty($this->prop['search_bind_dn']) &&
                        method_exists($this->ldap, 'domain_root_dn')) {
                    $this->ldap->bind($this->prop['search_bind_dn'], $this->prop['search_bind_pw']);
                    $dc = $this->ldap->domain_root_dn($d);
                }

                $replaces = array('%dn' => '', '%dc' => $dc, '%d' => $d, '%fu' => $fu, '%u' => $u);

                // Search for the dn to use to authenticate
                if ($this->prop['search_base_dn'] && $this->prop['search_filter']
                    && (strstr($bind_dn, '%dn') || strstr($this->base_dn, '%dn') || strstr($this->groups_base_dn, '%dn'))
                ) {
                    $search_attribs = array('uid');
                     if ($search_bind_attrib = (array)$this->prop['search_bind_attrib']) {
                         foreach ($search_bind_attrib as $r => $attr) {
                             $search_attribs[] = $attr;
                             $replaces[$r] = '';
                         }
                     }

                    $search_bind_dn = strtr($this->prop['search_bind_dn'], $replaces);
                    $search_base_dn = strtr($this->prop['search_base_dn'], $replaces);
                    $search_filter  = strtr($this->prop['search_filter'], $replaces);

                    $cache_key = 'DN.' . md5("$host:$search_bind_dn:$search_base_dn:$search_filter:"
                        .$this->prop['search_bind_pw']);

                    if ($this->cache && ($dn = $this->cache->get($cache_key))) {
                        $replaces['%dn'] = $dn;
                    }
                    else {
                        $ldap = $this->ldap;
                        if (!empty($search_bind_dn) && !empty($this->prop['search_bind_pw'])) {
                            // To protect from "Critical extension is unavailable" error
                            // we need to use a separate LDAP connection
                            if (!empty($this->prop['vlv'])) {
                                $ldap = new rcube_ldap_generic($this->prop);
                                $ldap->config_set(array('cache' => $this->cache, 'debug' => $this->debug));
                                if (!$ldap->connect($host)) {
                                    continue;
                                }
                            }

                            if (!$ldap->bind($search_bind_dn, $this->prop['search_bind_pw'])) {
                                continue;  // bind failed, try next host
                            }
                        }

                        $res = $ldap->search($search_base_dn, $search_filter, 'sub', $search_attribs);
                        if ($res) {
                            $res->rewind();
                            $replaces['%dn'] = key($res->entries(TRUE));

                            // add more replacements from 'search_bind_attrib' config
                            if ($search_bind_attrib) {
                                $res = $res->current();
                                foreach ($search_bind_attrib as $r => $attr) {
                                    $replaces[$r] = $res[$attr][0];
                                }
                            }
                        }

                        if ($ldap != $this->ldap) {
                            $ldap->close();
                        }
                    }

                    // DN not found
                    if (empty($replaces['%dn'])) {
                        if (!empty($this->prop['search_dn_default']))
                            $replaces['%dn'] = $this->prop['search_dn_default'];
                        else {
                            rcube::raise_error(array(
                                'code' => 100, 'type' => 'ldap',
                                'file' => __FILE__, 'line' => __LINE__,
                                'message' => "DN not found using LDAP search."), true);
                            continue;
                        }
                    }

                    if ($this->cache && !empty($replaces['%dn'])) {
                        $this->cache->set($cache_key, $replaces['%dn']);
                    }
                }

                // Replace the bind_dn and base_dn variables.
                $bind_dn              = strtr($bind_dn, $replaces);
                $this->base_dn        = strtr($this->base_dn, $replaces);
                $this->groups_base_dn = strtr($this->groups_base_dn, $replaces);

                // replace placeholders in filter settings
                if (!empty($this->prop['filter']))
                    $this->prop['filter'] = strtr($this->prop['filter'], $replaces);

                foreach (array('base_dn','filter','member_filter') as $k) {
                    if (!empty($this->prop['groups'][$k]))
                        $this->prop['groups'][$k] = strtr($this->prop['groups'][$k], $replaces);
                }

                if (is_array($this->prop['group_filters'])) {
                    foreach ($this->prop['group_filters'] as $i => $gf) {
                        if (!empty($gf['base_dn']))
                            $this->prop['group_filters'][$i]['base_dn'] = strtr($gf['base_dn'], $replaces);
                        if (!empty($gf['filter']))
                            $this->prop['group_filters'][$i]['filter'] = strtr($gf['filter'], $replaces);
                    }
                }

                if (empty($bind_user)) {
                    $bind_user = $u;
                }
            }

            if (empty($bind_pass)) {
                $this->ready = true;
            }
            else {
                if (!empty($bind_dn)) {
                    $this->ready = $this->ldap->bind($bind_dn, $bind_pass);
                }
                else if (!empty($this->prop['auth_cid'])) {
                    $this->ready = $this->ldap->sasl_bind($this->prop['auth_cid'], $bind_pass, $bind_user);
                }
                else {
                    $this->ready = $this->ldap->sasl_bind($bind_user, $bind_pass);
                }
            }

            // connection established, we're done here
            if ($this->ready) {
                break;
            }

        }  // end foreach hosts

        if (!is_resource($this->ldap->conn)) {
            rcube::raise_error(array('code' => 100, 'type' => 'ldap',
                'file' => __FILE__, 'line' => __LINE__,
                'message' => "Could not connect to any LDAP server, last tried $host"), true);

            return false;
        }

        return $this->ready;
    }

    /**
     * Close connection to LDAP server
     */
    function close()
    {
        if ($this->ldap) {
            $this->ldap->close();
        }
    }

    /**
     * Returns address book name
     *
     * @return string Address book name
     */
    function get_name()
    {
        return $this->prop['name'];
    }

    /**
     * Set internal list page
     *
     * @param  number  Page number to list
     */
    function set_page($page)
    {
        $this->list_page = (int)$page;
        $this->ldap->set_vlv_page($this->list_page, $this->page_size);
    }

    /**
     * Set internal page size
     *
     * @param  number  Number of records to display on one page
     */
    function set_pagesize($size)
    {
        $this->page_size = (int)$size;
        $this->ldap->set_vlv_page($this->list_page, $this->page_size);
    }

    /**
     * Set internal sort settings
     *
     * @param string $sort_col Sort column
     * @param string $sort_order Sort order
     */
    function set_sort_order($sort_col, $sort_order = null)
    {
        if ($this->coltypes[$sort_col]['attributes'])
            $this->sort_col = $this->coltypes[$sort_col]['attributes'][0];
    }

    /**
     * Save a search string for future listings
     *
     * @param string $filter Filter string
     */
    function set_search_set($filter)
    {
        $this->filter = $filter;
    }

    /**
     * Getter for saved search properties
     *
     * @return mixed Search properties used by this class
     */
    function get_search_set()
    {
        return $this->filter;
    }

    /**
     * Reset all saved results and search parameters
     */
    function reset()
    {
        $this->result = null;
        $this->ldap_result = null;
        $this->filter = '';
    }

    /**
     * List the current set of contact records
     *
     * @param array List of cols to show
     * @param int   Only return this number of records
     *
     * @return array Indexed list of contact records, each a hash array
     */
    function list_records($cols=null, $subset=0)
    {
        if ($this->prop['searchonly'] && empty($this->filter) && !$this->group_id) {
            $this->result = new rcube_result_set(0);
            $this->result->searchonly = true;
            return $this->result;
        }

        // fetch group members recursively
        if ($this->group_id && $this->group_data['dn']) {
            $entries = $this->list_group_members($this->group_data['dn']);

            // make list of entries unique and sort it
            $seen = array();
            foreach ($entries as $i => $rec) {
                if ($seen[$rec['dn']]++)
                    unset($entries[$i]);
            }
            usort($entries, array($this, '_entry_sort_cmp'));

            $entries['count'] = count($entries);
            $this->result = new rcube_result_set($entries['count'], ($this->list_page-1) * $this->page_size);
        }
        else {
            $prop    = $this->group_id ? $this->group_data : $this->prop;
            $base_dn = $this->group_id ? $prop['base_dn'] : $this->base_dn;

            // use global search filter
            if (!empty($this->filter))
                $prop['filter'] = $this->filter;

            // exec LDAP search if no result resource is stored
            if ($this->ready && !$this->ldap_result)
                $this->ldap_result = $this->ldap->search($base_dn, $prop['filter'], $prop['scope'], $this->prop['attributes'], $prop);

            // count contacts for this user
            $this->result = $this->count();

            // we have a search result resource
            if ($this->ldap_result && $this->result->count > 0) {
                // sorting still on the ldap server
                if ($this->sort_col && $prop['scope'] !== 'base' && !$this->ldap->vlv_active)
                    $this->ldap_result->sort($this->sort_col);

                // get all entries from the ldap server
                $entries = $this->ldap_result->entries();
            }

        }  // end else

        // start and end of the page
        $start_row = $this->ldap->vlv_active ? 0 : $this->result->first;
        $start_row = $subset < 0 ? $start_row + $this->page_size + $subset : $start_row;
        $last_row = $this->result->first + $this->page_size;
        $last_row = $subset != 0 ? $start_row + abs($subset) : $last_row;

        // filter entries for this page
        for ($i = $start_row; $i < min($entries['count'], $last_row); $i++)
            $this->result->add($this->_ldap2result($entries[$i]));

        return $this->result;
    }

    /**
     * Get all members of the given group
     *
     * @param string  Group DN
     * @param boolean Count only
     * @param array   Group entries (if called recursively)
     * @return array  Accumulated group members
     */
    function list_group_members($dn, $count = false, $entries = null)
    {
        $group_members = array();

        // fetch group object
        if (empty($entries)) {
            $attribs = array_merge(array('dn','objectClass','memberURL'), array_values($this->group_types));
            $entries = $this->ldap->read_entries($dn, '(objectClass=*)', $attribs);
            if ($entries === false) {
                return $group_members;
            }
        }

        for ($i=0; $i < $entries['count']; $i++) {
            $entry = $entries[$i];
            $attrs = array();

            foreach ((array)$entry['objectclass'] as $objectclass) {
                if (($member_attr = $this->get_group_member_attr(array($objectclass), ''))
                    && ($member_attr = strtolower($member_attr)) && !in_array($member_attr, $attrs)
                ) {
                    $members       = $this->_list_group_members($dn, $entry, $member_attr, $count);
                    $group_members = array_merge($group_members, $members);
                    $attrs[]       = $member_attr;
                }
                else if (!empty($entry['memberurl'])) {
                    $members       = $this->_list_group_memberurl($dn, $entry, $count);
                    $group_members = array_merge($group_members, $members);
                }

                if ($this->prop['sizelimit'] && count($group_members) > $this->prop['sizelimit']) {
                    break 2;
                }
            }
        }

        return array_filter($group_members);
    }

    /**
     * Fetch members of the given group entry from server
     *
     * @param string Group DN
     * @param array  Group entry
     * @param string Member attribute to use
     * @param boolean Count only
     * @return array Accumulated group members
     */
    private function _list_group_members($dn, $entry, $attr, $count)
    {
        // Use the member attributes to return an array of member ldap objects
        // NOTE that the member attribute is supposed to contain a DN
        $group_members = array();
        if (empty($entry[$attr])) {
            return $group_members;
        }

        // read these attributes for all members
        $attrib = $count ? array('dn','objectClass') : $this->prop['list_attributes'];
        $attrib = array_merge($attrib, array_values($this->group_types));
        $attrib[] = 'memberURL';

        $filter = $this->prop['groups']['member_filter'] ?: '(objectclass=*)';

        for ($i=0; $i < $entry[$attr]['count']; $i++) {
            if (empty($entry[$attr][$i]))
                continue;

            $members = $this->ldap->read_entries($entry[$attr][$i], $filter, $attrib);
            if ($members == false) {
                $members = array();
            }

            // for nested groups, call recursively
            $nested_group_members = $this->list_group_members($entry[$attr][$i], $count, $members);

            unset($members['count']);
            $group_members = array_merge($group_members, array_filter($members), $nested_group_members);
        }

        return $group_members;
    }

    /**
     * List members of group class groupOfUrls
     *
     * @param string Group DN
     * @param array  Group entry
     * @param boolean True if only used for counting
     * @return array Accumulated group members
     */
    private function _list_group_memberurl($dn, $entry, $count)
    {
        $group_members = array();

        for ($i=0; $i < $entry['memberurl']['count']; $i++) {
            // extract components from url
            if (!preg_match('!ldap://[^/]*/([^\?]+)\?\?(\w+)\?(.*)$!', $entry['memberurl'][$i], $m)) {
                continue;
            }

            // add search filter if any
            $filter = $this->filter ? '(&(' . $m[3] . ')(' . $this->filter . '))' : $m[3];
            $attrs = $count ? array('dn','objectClass') : $this->prop['list_attributes'];
            if ($result = $this->ldap->search($m[1], $filter, $m[2], $attrs, $this->group_data)) {
                $entries = $result->entries();
                for ($j = 0; $j < $entries['count']; $j++) {
                    if ($this->is_group_entry($entries[$j]) && ($nested_group_members = $this->list_group_members($entries[$j]['dn'], $count)))
                        $group_members = array_merge($group_members, $nested_group_members);
                    else
                        $group_members[] = $entries[$j];
                }
            }
        }

        return $group_members;
    }

    /**
     * Callback for sorting entries
     */
    function _entry_sort_cmp($a, $b)
    {
        return strcmp($a[$this->sort_col][0], $b[$this->sort_col][0]);
    }

    /**
     * Search contacts
     *
     * @param mixed   $fields   The field name of array of field names to search in
     * @param mixed   $value    Search value (or array of values when $fields is array)
     * @param int     $mode     Matching mode:
     *                          0 - partial (*abc*),
     *                          1 - strict (=),
     *                          2 - prefix (abc*)
     * @param boolean $select   True if results are requested, False if count only
     * @param boolean $nocount  (Not used)
     * @param array   $required List of fields that cannot be empty
     *
     * @return array  Indexed list of contact records and 'count' value
     */
    function search($fields, $value, $mode=0, $select=true, $nocount=false, $required=array())
    {
        $mode = intval($mode);

        // special treatment for ID-based search
        if ($fields == 'ID' || $fields == $this->primary_key) {
            $ids = !is_array($value) ? explode(',', $value) : $value;
            $result = new rcube_result_set();
            foreach ($ids as $id) {
                if ($rec = $this->get_record($id, true)) {
                    $result->add($rec);
                    $result->count++;
                }
            }
            return $result;
        }

        // use VLV pseudo-search for autocompletion
        $rcube = rcube::get_instance();
        $list_fields = $rcube->config->get('contactlist_fields');

        if ($this->prop['vlv_search'] && $this->ready && join(',', (array)$fields) == join(',', $list_fields)) {
            $this->result = new rcube_result_set(0);

            $this->ldap->config_set('fuzzy_search', intval($this->prop['fuzzy_search'] && $mode != 1));
            $ldap_data = $this->ldap->search($this->base_dn, $this->prop['filter'], $this->prop['scope'], $this->prop['attributes'],
                array('search' => $value /*, 'sort' => $this->prop['sort'] */));
            if ($ldap_data === false) {
                return $this->result;
            }

            // get all entries of this page and post-filter those that really match the query
            $search = mb_strtolower($value);
            foreach ($ldap_data as $entry) {
                $rec = $this->_ldap2result($entry);
                foreach ($fields as $f) {
                    foreach ((array)$rec[$f] as $val) {
                        if ($this->compare_search_value($f, $val, $search, $mode)) {
                            $this->result->add($rec);
                            $this->result->count++;
                            break 2;
                        }
                    }
                }
            }

            return $this->result;
        }

        // advanced per-attribute search
        if (is_array($value)) {
            // use AND operator for advanced searches
            $filter = '(&';

            // set wildcards
            $wp = $ws = '';
            if (!empty($this->prop['fuzzy_search']) && $mode != 1) {
                $ws = '*';
                if (!$mode) {
                    $wp = '*';
                }
            }

            foreach ((array)$fields as $idx => $field) {
                $val = $value[$idx];
                if (!strlen($val))
                    continue;
                if ($attrs = $this->_map_field($field)) {
                    if (count($attrs) > 1)
                        $filter .= '(|';
                    foreach ($attrs as $f)
                        $filter .= "($f=$wp" . rcube_ldap_generic::quote_string($val) . "$ws)";
                    if (count($attrs) > 1)
                        $filter .= ')';
                }
            }

            $filter .= ')';
        }
        else {
            if ($fields == '*') {
                // search_fields are required for fulltext search
                if (empty($this->prop['search_fields'])) {
                    $this->set_error(self::ERROR_SEARCH, 'nofulltextsearch');
                    $this->result = new rcube_result_set();
                    return $this->result;
                }
                $attributes = (array)$this->prop['search_fields'];
            }
            else {
                // map address book fields into ldap attributes
                $attributes = array();
                foreach ((array) $fields as $field) {
                    if ($this->coltypes[$field] && ($attrs = $this->coltypes[$field]['attributes'])) {
                        $attributes = array_merge($attributes, (array) $attrs);
                    }
                }
            }

            // compose a full-text-like search filter
            $filter = rcube_ldap_generic::fulltext_search_filter($value, $attributes, $mode);
        }

        // add required (non empty) fields filter
        $req_filter = '';
        foreach ((array)$required as $field) {
            if (in_array($field, (array)$fields))  // required field is already in search filter
                continue;
            if ($attrs = $this->_map_field($field)) {
                if (count($attrs) > 1)
                    $req_filter .= '(|';
                foreach ($attrs as $f)
                    $req_filter .= "($f=*)";
                if (count($attrs) > 1)
                    $req_filter .= ')';
            }
        }

        if (!empty($req_filter))
            $filter = '(&' . $req_filter . $filter . ')';

        // avoid double-wildcard if $value is empty
        $filter = preg_replace('/\*+/', '*', $filter);

        // add general filter to query
        if (!empty($this->prop['filter']))
            $filter = '(&(' . preg_replace('/^\(|\)$/', '', $this->prop['filter']) . ')' . $filter . ')';

        // set filter string and execute search
        $this->set_search_set($filter);

        if ($select)
            $this->list_records();
        else
            $this->result = $this->count();

        return $this->result;
    }

    /**
     * Count number of available contacts in database
     *
     * @return object rcube_result_set Resultset with values for 'count' and 'first'
     */
    function count()
    {
        $count = 0;
        if ($this->ldap_result) {
            $count = $this->ldap_result->count();
        }
        else if ($this->group_id && $this->group_data['dn']) {
            $count = count($this->list_group_members($this->group_data['dn'], true));
        }
        // We have a connection but no result set, attempt to get one.
        else if ($this->ready) {
            $prop    = $this->group_id ? $this->group_data : $this->prop;
            $base_dn = $this->group_id ? $this->group_base_dn : $this->base_dn;

            if (!empty($this->filter)) {  // Use global search filter
                $prop['filter'] = $this->filter;
            }
            $count = $this->ldap->search($base_dn, $prop['filter'], $prop['scope'], array('dn'), $prop, true);
        }

        return new rcube_result_set($count, ($this->list_page-1) * $this->page_size);
    }

    /**
     * Return the last result set
     *
     * @return object rcube_result_set Current resultset or NULL if nothing selected yet
     */
    function get_result()
    {
        return $this->result;
    }

    /**
     * Get a specific contact record
     *
     * @param mixed   Record identifier
     * @param boolean Return as associative array
     *
     * @return mixed  Hash array or rcube_result_set with all record fields
     */
    function get_record($dn, $assoc=false)
    {
        $res = $this->result = null;

        if ($this->ready && $dn) {
            $dn = self::dn_decode($dn);

            if ($rec = $this->ldap->get_entry($dn)) {
                $rec = array_change_key_case($rec, CASE_LOWER);
            }

            // Use ldap_list to get subentries like country (c) attribute (#1488123)
            if (!empty($rec) && $this->sub_filter) {
                if ($entries = $this->ldap->list_entries($dn, $this->sub_filter, array_keys($this->prop['sub_fields']))) {
                    foreach ($entries as $entry) {
                        $lrec = array_change_key_case($entry, CASE_LOWER);
                        $rec  = array_merge($lrec, $rec);
                    }
                }
            }

            if (!empty($rec)) {
                // Add in the dn for the entry.
                $rec['dn'] = $dn;
                $res = $this->_ldap2result($rec);
                $this->result = new rcube_result_set(1);
                $this->result->add($res);
            }
        }

        return $assoc ? $res : $this->result;
    }

    /**
     * Returns the last error occurred (e.g. when updating/inserting failed)
     *
     * @return array Hash array with the following fields: type, message
     */
    function get_error()
    {
        $err = $this->error;

        // check ldap connection for errors
        if (!$err && $this->ldap->get_error()) {
            $err = array(self::ERROR_SEARCH, $this->ldap->get_error());
        }

        return $err;
    }

    /**
     * Check the given data before saving.
     * If input not valid, the message to display can be fetched using get_error()
     *
     * @param array Assoziative array with data to save
     * @param boolean Try to fix/complete record automatically
     * @return boolean True if input is valid, False if not.
     */
    public function validate(&$save_data, $autofix = false)
    {
        // validate e-mail addresses
        if (!parent::validate($save_data, $autofix)) {
            return false;
        }

        // check for name input
        if (empty($save_data['name'])) {
            $this->set_error(self::ERROR_VALIDATE, 'nonamewarning');
            return false;
        }

        // Verify that the required fields are set.
        $missing = null;
        $ldap_data = $this->_map_data($save_data);
        foreach ($this->prop['required_fields'] as $fld) {
            if (!isset($ldap_data[$fld]) || $ldap_data[$fld] === '') {
                $missing[$fld] = 1;
            }
        }

        if ($missing) {
            // try to complete record automatically
            if ($autofix) {
                $sn_field    = $this->fieldmap['surname'];
                $fn_field    = $this->fieldmap['firstname'];
                $mail_field  = $this->fieldmap['email'];

                // try to extract surname and firstname from displayname
                $name_parts  = preg_split('/[\s,.]+/', $save_data['name']);

                if ($sn_field && $missing[$sn_field]) {
                    $save_data['surname'] = array_pop($name_parts);
                    unset($missing[$sn_field]);
                }

                if ($fn_field && $missing[$fn_field]) {
                    $save_data['firstname'] = array_shift($name_parts);
                    unset($missing[$fn_field]);
                }

                // try to fix missing e-mail, very often on import
                // from vCard we have email:other only defined
                if ($mail_field && $missing[$mail_field]) {
                    $emails = $this->get_col_values('email', $save_data, true);
                    if (!empty($emails) && ($email = array_shift($emails))) {
                        $save_data['email'] = $email;
                        unset($missing[$mail_field]);
                    }
                }
            }

            // TODO: generate message saying which fields are missing
            if (!empty($missing)) {
                $this->set_error(self::ERROR_VALIDATE, 'formincomplete');
                return false;
            }
        }

        return true;
    }

    /**
     * Create a new contact record
     *
     * @param array Associative array with save data
     *  Keys:   Field name with optional section in the form FIELD:SECTION
     *  Values: Field value. Can be either a string or an array of strings for multiple values
     * @param boolean True to check for duplicates first
     *
     * @return mixed The created record ID on success, False on error
     */
    function insert($save_cols, $check = false)
    {
        // Map out the column names to their LDAP ones to build the new entry.
        $newentry = $this->_map_data($save_cols);
        $newentry['objectClass'] = $this->prop['LDAP_Object_Classes'];

        // add automatically generated attributes
        $this->add_autovalues($newentry);

        // Verify that the required fields are set.
        $missing = null;
        foreach ($this->prop['required_fields'] as $fld) {
            if (!isset($newentry[$fld])) {
                $missing[] = $fld;
            }
        }

        // abort process if requiered fields are missing
        // TODO: generate message saying which fields are missing
        if ($missing) {
            $this->set_error(self::ERROR_VALIDATE, 'formincomplete');
            return false;
        }

        // Build the new entries DN.
        $dn = $this->prop['LDAP_rdn'].'='.rcube_ldap_generic::quote_string($newentry[$this->prop['LDAP_rdn']], true).','.$this->base_dn;

        // Remove attributes that need to be added separately (child objects)
        $xfields = array();
        if (!empty($this->prop['sub_fields']) && is_array($this->prop['sub_fields'])) {
            foreach (array_keys($this->prop['sub_fields']) as $xf) {
                if (!empty($newentry[$xf])) {
                    $xfields[$xf] = $newentry[$xf];
                    unset($newentry[$xf]);
                }
            }
        }

        if (!$this->ldap->add_entry($dn, $newentry)) {
            $this->set_error(self::ERROR_SAVING, 'errorsaving');
            return false;
        }

        foreach ($xfields as $xidx => $xf) {
            $xdn = $xidx.'='.rcube_ldap_generic::quote_string($xf).','.$dn;
            $xf = array(
                $xidx => $xf,
                'objectClass' => (array) $this->prop['sub_fields'][$xidx],
            );

            $this->ldap->add_entry($xdn, $xf);
        }

        $dn = self::dn_encode($dn);

        // add new contact to the selected group
        if ($this->group_id)
            $this->add_to_group($this->group_id, $dn);

        return $dn;
    }

    /**
     * Update a specific contact record
     *
     * @param mixed Record identifier
     * @param array Hash array with save data
     *
     * @return boolean True on success, False on error
     */
    function update($id, $save_cols)
    {
        $record = $this->get_record($id, true);

        $newdata     = array();
        $replacedata = array();
        $deletedata  = array();
        $subdata     = array();
        $subdeldata  = array();
        $subnewdata  = array();

        $ldap_data = $this->_map_data($save_cols);
        $old_data  = $record['_raw_attrib'];

        // special handling of photo col
        if ($photo_fld = $this->fieldmap['photo']) {
            // undefined means keep old photo
            if (!array_key_exists('photo', $save_cols)) {
                $ldap_data[$photo_fld] = $record['photo'];
            }
        }

        foreach ($this->fieldmap as $fld) {
            if ($fld) {
                $val = $ldap_data[$fld];
                $old = $old_data[$fld];
                // remove empty array values
                if (is_array($val))
                    $val = array_filter($val);
                // $this->_map_data() result and _raw_attrib use different format
                // make sure comparing array with one element with a string works as expected
                if (is_array($old) && count($old) == 1 && !is_array($val)) {
                    $old = array_pop($old);
                }
                if (is_array($val) && count($val) == 1 && !is_array($old)) {
                    $val = array_pop($val);
                }
                // Subentries must be handled separately
                if (!empty($this->prop['sub_fields']) && isset($this->prop['sub_fields'][$fld])) {
                    if ($old != $val) {
                        if ($old !== null) {
                            $subdeldata[$fld] = $old;
                        }
                        if ($val) {
                            $subnewdata[$fld] = $val;
                        }
                    }
                    else if ($old !== null) {
                        $subdata[$fld] = $old;
                    }
                    continue;
                }

                // The field does exist compare it to the ldap record.
                if ($old != $val) {
                    // Changed, but find out how.
                    if ($old === null) {
                        // Field was not set prior, need to add it.
                        $newdata[$fld] = $val;
                    }
                    else if ($val == '') {
                        // Field supplied is empty, verify that it is not required.
                        if (!in_array($fld, $this->prop['required_fields'])) {
                            // ...It is not, safe to clear.
                            // #1488420: Workaround "ldap_mod_del(): Modify: Inappropriate matching in..."
                            // jpegPhoto attribute require an array() here. It looks to me that it works for other attribs too
                            $deletedata[$fld] = array();
                            //$deletedata[$fld] = $old_data[$fld];
                        }
                    }
                    else {
                        // The data was modified, save it out.
                        $replacedata[$fld] = $val;
                    }
                } // end if
            } // end if
        } // end foreach

        // console($old_data, $ldap_data, '----', $newdata, $replacedata, $deletedata, '----', $subdata, $subnewdata, $subdeldata);

        $dn = self::dn_decode($id);

        // Update the entry as required.
        if (!empty($deletedata)) {
            // Delete the fields.
            if (!$this->ldap->mod_del($dn, $deletedata)) {
                $this->set_error(self::ERROR_SAVING, 'errorsaving');
                return false;
            }
        } // end if

        if (!empty($replacedata)) {
            // Handle RDN change
            if ($replacedata[$this->prop['LDAP_rdn']]) {
                $newdn = $this->prop['LDAP_rdn'].'='
                    .rcube_ldap_generic::quote_string($replacedata[$this->prop['LDAP_rdn']], true)
                    .','.$this->base_dn;
                if ($dn != $newdn) {
                    $newrdn = $this->prop['LDAP_rdn'].'='
                    .rcube_ldap_generic::quote_string($replacedata[$this->prop['LDAP_rdn']], true);
                    unset($replacedata[$this->prop['LDAP_rdn']]);
                }
            }
            // Replace the fields.
            if (!empty($replacedata)) {
                if (!$this->ldap->mod_replace($dn, $replacedata)) {
                    $this->set_error(self::ERROR_SAVING, 'errorsaving');
                    return false;
                }
            }
        } // end if

        // RDN change, we need to remove all sub-entries
        if (!empty($newrdn)) {
            $subdeldata = array_merge($subdeldata, $subdata);
            $subnewdata = array_merge($subnewdata, $subdata);
        }

        // remove sub-entries
        if (!empty($subdeldata)) {
            foreach ($subdeldata as $fld => $val) {
                $subdn = $fld.'='.rcube_ldap_generic::quote_string($val).','.$dn;
                if (!$this->ldap->delete_entry($subdn)) {
                    return false;
                }
            }
        }

        if (!empty($newdata)) {
            // Add the fields.
            if (!$this->ldap->mod_add($dn, $newdata)) {
                $this->set_error(self::ERROR_SAVING, 'errorsaving');
                return false;
            }
        } // end if

        // Handle RDN change
        if (!empty($newrdn)) {
            if (!$this->ldap->rename($dn, $newrdn, null, true)) {
                $this->set_error(self::ERROR_SAVING, 'errorsaving');
                return false;
            }

            $dn    = self::dn_encode($dn);
            $newdn = self::dn_encode($newdn);

            // change the group membership of the contact
            if ($this->groups) {
                $group_ids = $this->get_record_groups($dn);
                foreach (array_keys($group_ids) as $group_id) {
                    $this->remove_from_group($group_id, $dn);
                    $this->add_to_group($group_id, $newdn);
                }
            }

            $dn = self::dn_decode($newdn);
        }

        // add sub-entries
        if (!empty($subnewdata)) {
            foreach ($subnewdata as $fld => $val) {
                $subdn = $fld.'='.rcube_ldap_generic::quote_string($val).','.$dn;
                $xf = array(
                    $fld => $val,
                    'objectClass' => (array) $this->prop['sub_fields'][$fld],
                );
                $this->ldap->add_entry($subdn, $xf);
            }
        }

        return $newdn ?: true;
    }

    /**
     * Mark one or more contact records as deleted
     *
     * @param array   Record identifiers
     * @param boolean Remove record(s) irreversible (unsupported)
     *
     * @return boolean True on success, False on error
     */
    function delete($ids, $force=true)
    {
        if (!is_array($ids)) {
            // Not an array, break apart the encoded DNs.
            $ids = explode(',', $ids);
        } // end if

        foreach ($ids as $id) {
            $dn = self::dn_decode($id);

            // Need to delete all sub-entries first
            if ($this->sub_filter) {
                if ($entries = $this->ldap->list_entries($dn, $this->sub_filter)) {
                    foreach ($entries as $entry) {
                        if (!$this->ldap->delete_entry($entry['dn'])) {
                            $this->set_error(self::ERROR_SAVING, 'errorsaving');
                            return false;
                        }
                    }
                }
            }

            // Delete the record.
            if (!$this->ldap->delete_entry($dn)) {
                $this->set_error(self::ERROR_SAVING, 'errorsaving');
                return false;
            }

            // remove contact from all groups where he was a member
            if ($this->groups) {
                $dn = self::dn_encode($dn);
                $group_ids = $this->get_record_groups($dn);
                foreach (array_keys($group_ids) as $group_id) {
                    $this->remove_from_group($group_id, $dn);
                }
            }
        } // end foreach

        return count($ids);
    }

    /**
     * Remove all contact records
     *
     * @param bool $with_groups Delete also groups if enabled
     */
    function delete_all($with_groups = false)
    {
        // searching for contact entries
        $dn_list = $this->ldap->list_entries($this->base_dn, $this->prop['filter'] ?: '(objectclass=*)');

        if (!empty($dn_list)) {
            foreach ($dn_list as $idx => $entry) {
                $dn_list[$idx] = self::dn_encode($entry['dn']);
            }
            $this->delete($dn_list);
        }

        if ($with_groups && $this->groups && ($groups = $this->_fetch_groups()) && count($groups)) {
            foreach ($groups as $group) {
                $this->ldap->delete_entry($group['dn']);
            }

            if ($this->cache) {
                $this->cache->remove('groups');
            }
        }
    }

    /**
     * Generate missing attributes as configured
     *
     * @param array LDAP record attributes
     */
    protected function add_autovalues(&$attrs)
    {
        if (empty($this->prop['autovalues'])) {
            return;
        }

        $attrvals = array();
        foreach ($attrs as $k => $v) {
            $attrvals['{'.$k.'}'] = is_array($v) ? $v[0] : $v;
        }

        foreach ((array)$this->prop['autovalues'] as $lf => $templ) {
            if (empty($attrs[$lf])) {
                if (strpos($templ, '(') !== false) {
                    // replace {attr} placeholders with (escaped!) attribute values to be safely eval'd
                    $code = preg_replace('/\{\w+\}/', '', strtr($templ, array_map('addslashes', $attrvals)));
                    $fn   = create_function('', "return ($code);");
                    if (!$fn) {
                        rcube::raise_error(array(
                            'code' => 505, 'type' => 'php',
                            'file' => __FILE__, 'line' => __LINE__,
                            'message' => "Expression parse error on: ($code)"), true, false);
                        continue;
                    }

                    $attrs[$lf] = $fn();
                }
                else {
                    // replace {attr} placeholders with concrete attribute values
                    $attrs[$lf] = preg_replace('/\{\w+\}/', '', strtr($templ, $attrvals));
                }
            }
        }
    }

    /**
     * Converts LDAP entry into an array
     */
    private function _ldap2result($rec)
    {
        $out = array('_type' => 'person');
        $fieldmap = $this->fieldmap;

        if ($rec['dn'])
            $out[$this->primary_key] = self::dn_encode($rec['dn']);

        // determine record type
        if ($this->is_group_entry($rec)) {
            $out['_type'] = 'group';
            $out['readonly'] = true;
            $fieldmap['name'] = $this->group_data['name_attr'] ?: $this->prop['groups']['name_attr'];
        }

        // assign object type from object class mapping
        if (!empty($this->prop['class_type_map'])) {
            foreach (array_map('strtolower', (array)$rec['objectclass']) as $objcls) {
                if (!empty($this->prop['class_type_map'][$objcls])) {
                    $out['_type'] = $this->prop['class_type_map'][$objcls];
                    break;
                }
            }
        }

        foreach ($fieldmap as $rf => $lf)
        {
            for ($i=0; $i < $rec[$lf]['count']; $i++) {
                if (!($value = $rec[$lf][$i]))
                    continue;

                list($col, $subtype) = explode(':', $rf);
                $out['_raw_attrib'][$lf][$i] = $value;

                if ($col == 'email' && $this->mail_domain && !strpos($value, '@'))
                    $out[$rf][] = sprintf('%s@%s', $value, $this->mail_domain);
                else if (in_array($col, array('street','zipcode','locality','country','region')))
                    $out['address' . ($subtype ? ':' : '') . $subtype][$i][$col] = $value;
                else if ($col == 'address' && strpos($value, '$') !== false)  // address data is represented as string separated with $
                    list($out[$rf][$i]['street'], $out[$rf][$i]['locality'], $out[$rf][$i]['zipcode'], $out[$rf][$i]['country']) = explode('$', $value);
                else if ($rec[$lf]['count'] > 1)
                    $out[$rf][] = $value;
                else
                    $out[$rf] = $value;
            }

            // Make sure name fields aren't arrays (#1488108)
            if (is_array($out[$rf]) && in_array($rf, array('name', 'surname', 'firstname', 'middlename', 'nickname'))) {
                $out[$rf] = $out['_raw_attrib'][$lf] = $out[$rf][0];
            }
        }

        return $out;
    }

    /**
     * Return LDAP attribute(s) for the given field
     */
    private function _map_field($field)
    {
        return (array)$this->coltypes[$field]['attributes'];
    }

    /**
     * Convert a record data set into LDAP field attributes
     */
    private function _map_data($save_cols)
    {
        // flatten composite fields first
        foreach ($this->coltypes as $col => $colprop) {
            if (is_array($colprop['childs']) && ($values = $this->get_col_values($col, $save_cols, false))) {
                foreach ($values as $subtype => $childs) {
                    $subtype = $subtype ? ':'.$subtype : '';
                    foreach ($childs as $i => $child_values) {
                        foreach ((array)$child_values as $childcol => $value) {
                            $save_cols[$childcol.$subtype][$i] = $value;
                        }
                    }
                }
            }

            // if addresses are to be saved as serialized string, do so
            if (is_array($colprop['serialized'])) {
               foreach ($colprop['serialized'] as $subtype => $delim) {
                  $key = $col.':'.$subtype;
                  foreach ((array)$save_cols[$key] as $i => $val) {
                     $values = array($val['street'], $val['locality'], $val['zipcode'], $val['country']);
                     $save_cols[$key][$i] = count(array_filter($values)) ? join($delim, $values) : null;
                 }
               }
            }
        }

        $ldap_data = array();
        foreach ($this->fieldmap as $rf => $fld) {
            $val = $save_cols[$rf];

            // check for value in base field (eg.g email instead of email:foo)
            list($col, $subtype) = explode(':', $rf);
            if (!$val && !empty($save_cols[$col])) {
                $val = $save_cols[$col];
                unset($save_cols[$col]);  // only use this value once
            }
            else if (!$val && !$subtype) { // extract values from subtype cols
                $val = $this->get_col_values($col, $save_cols, true);
            }

            if (is_array($val))
                $val = array_filter($val);  // remove empty entries
            if ($fld && $val) {
                // The field does exist, add it to the entry.
                $ldap_data[$fld] = $val;
            }
        }

        foreach ($this->formats as $fld => $format) {
            if (empty($ldap_data[$fld])) {
                continue;
            }

            switch ($format['type']) {
            case 'date':
                if ($dt = rcube_utils::anytodatetime($ldap_data[$fld])) {
                    $ldap_data[$fld] = $dt->format($format['format']);
                }
                break;
            }
        }

        return $ldap_data;
    }

    /**
     * Returns unified attribute name (resolving aliases)
     */
    private static function _attr_name($namev)
    {
        // list of known attribute aliases
        static $aliases = array(
            'gn'            => 'givenname',
            'rfc822mailbox' => 'email',
            'userid'        => 'uid',
            'emailaddress'  => 'email',
            'pkcs9email'    => 'email',
        );

        list($name, $limit) = explode(':', $namev, 2);
        $suffix = $limit ? ':'.$limit : '';
        $name   = strtolower($name);

        return (isset($aliases[$name]) ? $aliases[$name] : $name) . $suffix;
    }

    /**
     * Determines whether the given LDAP entry is a group record
     */
    private function is_group_entry($entry)
    {
        $classes = array_map('strtolower', (array)$entry['objectclass']);

        return count(array_intersect(array_keys($this->group_types), $classes)) > 0;
    }

    /**
     * Activate/deactivate debug mode
     *
     * @param boolean $dbg True if LDAP commands should be logged
     */
    function set_debug($dbg = true)
    {
        $this->debug = $dbg;

        if ($this->ldap) {
            $this->ldap->config_set('debug', $dbg);
        }
    }

    /**
     * Setter for the current group
     */
    function set_group($group_id)
    {
        if ($group_id) {
            $this->group_id = $group_id;
            $this->group_data = $this->get_group_entry($group_id);
        }
        else {
            $this->group_id = 0;
            $this->group_data = null;
        }
    }

    /**
     * List all active contact groups of this source
     *
     * @param string  Optional search string to match group name
     * @param int     Matching mode:
     *                0 - partial (*abc*),
     *                1 - strict (=),
     *                2 - prefix (abc*)
     *
     * @return array  Indexed list of contact groups, each a hash array
     */
    function list_groups($search = null, $mode = 0)
    {
        if (!$this->groups) {
            return array();
        }

        $group_cache = $this->_fetch_groups($search, $mode);
        $groups      = array();

        if ($search) {
            foreach ($group_cache as $group) {
                if ($this->compare_search_value('name', $group['name'], mb_strtolower($search), $mode)) {
                    $groups[] = $group;
                }
            }
        }
        else {
            $groups = $group_cache;
        }

        return array_values($groups);
    }

    /**
     * Fetch groups from server
     */
    private function _fetch_groups($search = null, $mode = 0, $vlv_page = null)
    {
        // reset group search cache
        if ($search !== null && $vlv_page === null) {
            $this->group_search_cache = null;
        }
        // return in-memory cache from previous search results
        else if (is_array($this->group_search_cache) && $vlv_page === null) {
            return $this->group_search_cache;
        }

        // special case: list groups from 'group_filters' config
        if ($vlv_page === null && $search === null && is_array($this->prop['group_filters'])) {
            $groups = array();
            $rcube  = rcube::get_instance();

            // list regular groups configuration as special filter
            if (!empty($this->prop['groups']['filter'])) {
                $id = '__groups__';
                $groups[$id] = array('ID' => $id, 'name' => $rcube->gettext('groups'), 'virtual' => true) + $this->prop['groups'];
            }

            foreach ($this->prop['group_filters'] as $id => $prop) {
                $groups[$id] = $prop + array('ID' => $id, 'name' => ucfirst($id), 'virtual' => true, 'base_dn' => $this->base_dn);
            }

            return $groups;
        }

        if ($this->cache && $search === null && $vlv_page === null && ($groups = $this->cache->get('groups')) !== null) {
            return $groups;
        }

        $base_dn    = $this->groups_base_dn;
        $filter     = $this->prop['groups']['filter'];
        $scope      = $this->prop['groups']['scope'];
        $name_attr  = $this->prop['groups']['name_attr'];
        $email_attr = $this->prop['groups']['email_attr'] ?: 'mail';
        $sort_attrs = $this->prop['groups']['sort'] ? (array)$this->prop['groups']['sort'] : array($name_attr);
        $sort_attr  = $sort_attrs[0];

        $ldap = $this->ldap;

        // use vlv to list groups
        if ($this->prop['groups']['vlv']) {
            $page_size = 200;
            if (!$this->prop['groups']['sort']) {
                $this->prop['groups']['sort'] = $sort_attrs;
            }

            $ldap = clone $this->ldap;
            $ldap->config_set($this->prop['groups']);
            $ldap->set_vlv_page($vlv_page+1, $page_size);
        }

        $props = array('sort' => $this->prop['groups']['sort']);
        $attrs = array_unique(array('dn', 'objectClass', $name_attr, $email_attr, $sort_attr));

        // add search filter
        if ($search !== null) {
            // set wildcards
            $wp = $ws = '';
            if (!empty($this->prop['fuzzy_search']) && $mode != 1) {
                $ws = '*';
                $wp = !$mode ? '*' : '';
            }
            $filter = "(&$filter($name_attr=$wp" . rcube_ldap_generic::quote_string($search) . "$ws))";
            $props['search'] = $wp . $search . $ws;
        }

        $ldap_data = $ldap->search($base_dn, $filter, $scope, $attrs, $props);

        if ($ldap_data === false) {
            return array();
        }

        $groups          = array();
        $group_sortnames = array();
        $group_count     = $ldap_data->count();

        foreach ($ldap_data as $entry) {
            if (!$entry['dn'])  // DN is mandatory
                $entry['dn'] = $ldap_data->get_dn();

            $group_name = is_array($entry[$name_attr]) ? $entry[$name_attr][0] : $entry[$name_attr];
            $group_id = self::dn_encode($entry['dn']);
            $groups[$group_id]['ID'] = $group_id;
            $groups[$group_id]['dn'] = $entry['dn'];
            $groups[$group_id]['name'] = $group_name;
            $groups[$group_id]['member_attr'] = $this->get_group_member_attr($entry['objectclass']);

            // list email attributes of a group
            for ($j=0; $entry[$email_attr] && $j < $entry[$email_attr]['count']; $j++) {
                if (strpos($entry[$email_attr][$j], '@') > 0)
                    $groups[$group_id]['email'][] = $entry[$email_attr][$j];
            }

            $group_sortnames[] = mb_strtolower($entry[$sort_attr][0]);
        }

        // recursive call can exit here
        if ($vlv_page > 0) {
            return $groups;
        }

        // call recursively until we have fetched all groups
        while ($this->prop['groups']['vlv'] && $group_count == $page_size) {
            $next_page   = $this->_fetch_groups($search, $mode, ++$vlv_page);
            $groups      = array_merge($groups, $next_page);
            $group_count = count($next_page);
        }

        // when using VLV the list of groups is already sorted
        if (!$this->prop['groups']['vlv']) {
            array_multisort($group_sortnames, SORT_ASC, SORT_STRING, $groups);
        }

        // cache this
        if ($this->cache && $search === null) {
            $this->cache->set('groups', $groups);
        }
        else if ($search !== null) {
            $this->group_search_cache = $groups;
        }

        return $groups;
    }

    /**
     * Fetch a group entry from LDAP and save in local cache
     */
    private function get_group_entry($group_id)
    {
        $group_cache = $this->_fetch_groups();

        // add group record to cache if it isn't yet there
        if (!isset($group_cache[$group_id])) {
            $name_attr = $this->prop['groups']['name_attr'];
            $dn = self::dn_decode($group_id);

            if ($list = $this->ldap->read_entries($dn, '(objectClass=*)', array('dn','objectClass','member','uniqueMember','memberURL',$name_attr,$this->fieldmap['email']))) {
                $entry = $list[0];
                $group_name = is_array($entry[$name_attr]) ? $entry[$name_attr][0] : $entry[$name_attr];
                $group_cache[$group_id]['ID'] = $group_id;
                $group_cache[$group_id]['dn'] = $dn;
                $group_cache[$group_id]['name'] = $group_name;
                $group_cache[$group_id]['member_attr'] = $this->get_group_member_attr($entry['objectclass']);
            }
            else {
                $group_cache[$group_id] = false;
            }

            if ($this->cache) {
                $this->cache->set('groups', $group_cache);
            }
        }

        return $group_cache[$group_id];
    }

    /**
     * Get group properties such as name and email address(es)
     *
     * @param string Group identifier
     * @return array Group properties as hash array
     */
    function get_group($group_id)
    {
        $group_data = $this->get_group_entry($group_id);
        unset($group_data['dn'], $group_data['member_attr']);

        return $group_data;
    }

    /**
     * Create a contact group with the given name
     *
     * @param string The group name
     * @return mixed False on error, array with record props in success
     */
    function create_group($group_name)
    {
        $new_dn      = 'cn=' . rcube_ldap_generic::quote_string($group_name, true) . ',' . $this->groups_base_dn;
        $new_gid     = self::dn_encode($new_dn);
        $member_attr = $this->get_group_member_attr();
        $name_attr   = $this->prop['groups']['name_attr'] ?: 'cn';
        $new_entry   = array(
            'objectClass' => $this->prop['groups']['object_classes'],
            $name_attr    => $group_name,
            $member_attr  => '',
        );

        if (!$this->ldap->add_entry($new_dn, $new_entry)) {
            $this->set_error(self::ERROR_SAVING, 'errorsaving');
            return false;
        }

        if ($this->cache) {
            $this->cache->remove('groups');
        }

        return array('id' => $new_gid, 'name' => $group_name);
    }

    /**
     * Delete the given group and all linked group members
     *
     * @param string Group identifier
     * @return boolean True on success, false if no data was changed
     */
    function delete_group($group_id)
    {
        $group_cache = $this->_fetch_groups();
        $del_dn      = $group_cache[$group_id]['dn'];

        if (!$this->ldap->delete_entry($del_dn)) {
            $this->set_error(self::ERROR_SAVING, 'errorsaving');
            return false;
        }

        if ($this->cache) {
            unset($group_cache[$group_id]);
            $this->cache->set('groups', $group_cache);
        }

        return true;
    }

    /**
     * Rename a specific contact group
     *
     * @param string Group identifier
     * @param string New name to set for this group
     * @param string New group identifier (if changed, otherwise don't set)
     * @return boolean New name on success, false if no data was changed
     */
    function rename_group($group_id, $new_name, &$new_gid)
    {
        $group_cache = $this->_fetch_groups();
        $old_dn      = $group_cache[$group_id]['dn'];
        $new_rdn     = "cn=" . rcube_ldap_generic::quote_string($new_name, true);
        $new_gid     = self::dn_encode($new_rdn . ',' . $this->groups_base_dn);

        if (!$this->ldap->rename($old_dn, $new_rdn, null, true)) {
            $this->set_error(self::ERROR_SAVING, 'errorsaving');
            return false;
        }

        if ($this->cache) {
            $this->cache->remove('groups');
        }

        return $new_name;
    }

    /**
     * Add the given contact records the a certain group
     *
     * @param string       Group identifier
     * @param array|string List of contact identifiers to be added
     *
     * @return int Number of contacts added
     */
    function add_to_group($group_id, $contact_ids)
    {
        $group_cache = $this->_fetch_groups();
        $member_attr = $group_cache[$group_id]['member_attr'];
        $group_dn    = $group_cache[$group_id]['dn'];
        $new_attrs   = array();

        if (!is_array($contact_ids)) {
            $contact_ids = explode(',', $contact_ids);
        }

        foreach ($contact_ids as $id) {
            $new_attrs[$member_attr][] = self::dn_decode($id);
        }

        if (!$this->ldap->mod_add($group_dn, $new_attrs)) {
            $this->set_error(self::ERROR_SAVING, 'errorsaving');
            return 0;
        }

        if ($this->cache) {
            $this->cache->remove('groups');
        }

        return count($new_attrs[$member_attr]);
    }

    /**
     * Remove the given contact records from a certain group
     *
     * @param string       Group identifier
     * @param array|string List of contact identifiers to be removed
     *
     * @return int Number of deleted group members
     */
    function remove_from_group($group_id, $contact_ids)
    {
        $group_cache = $this->_fetch_groups();
        $member_attr = $group_cache[$group_id]['member_attr'];
        $group_dn    = $group_cache[$group_id]['dn'];
        $del_attrs   = array();

        if (!is_array($contact_ids)) {
            $contact_ids = explode(',', $contact_ids);
        }

        foreach ($contact_ids as $id) {
            $del_attrs[$member_attr][] = self::dn_decode($id);
        }

        if (!$this->ldap->mod_del($group_dn, $del_attrs)) {
            $this->set_error(self::ERROR_SAVING, 'errorsaving');
            return 0;
        }

        if ($this->cache) {
            $this->cache->remove('groups');
        }

        return count($del_attrs[$member_attr]);
    }

    /**
     * Get group assignments of a specific contact record
     *
     * @param mixed Record identifier
     *
     * @return array List of assigned groups as ID=>Name pairs
     * @since 0.5-beta
     */
    function get_record_groups($contact_id)
    {
        if (!$this->groups) {
            return array();
        }

        $base_dn     = $this->groups_base_dn;
        $contact_dn  = self::dn_decode($contact_id);
        $name_attr   = $this->prop['groups']['name_attr'] ?: 'cn';
        $member_attr = $this->get_group_member_attr();
        $add_filter  = '';

        if ($member_attr != 'member' && $member_attr != 'uniqueMember')
            $add_filter = "($member_attr=$contact_dn)";
        $filter = strtr("(|(member=$contact_dn)(uniqueMember=$contact_dn)$add_filter)", array('\\' => '\\\\'));

        $ldap_data = $this->ldap->search($base_dn, $filter, 'sub', array('dn', $name_attr));
        if ($ldap_data === false) {
            return array();
        }

        $groups = array();
        foreach ($ldap_data as $entry) {
            if (!$entry['dn'])
                $entry['dn'] = $ldap_data->get_dn();
            $group_name = $entry[$name_attr][0];
            $group_id = self::dn_encode($entry['dn']);
            $groups[$group_id] = $group_name;
        }

        return $groups;
    }

    /**
     * Detects group member attribute name
     */
    private function get_group_member_attr($object_classes = array(), $default = 'member')
    {
        if (empty($object_classes)) {
            $object_classes = $this->prop['groups']['object_classes'];
        }

        if (!empty($object_classes)) {
            foreach ((array)$object_classes as $oc) {
                if ($attr = $this->group_types[strtolower($oc)]) {
                    return $attr;
                }
            }
        }

        if (!empty($this->prop['groups']['member_attr'])) {
            return $this->prop['groups']['member_attr'];
        }

        return $default;
    }

    /**
     * HTML-safe DN string encoding
     *
     * @param string $str DN string
     *
     * @return string Encoded HTML identifier string
     */
    static function dn_encode($str)
    {
        // @TODO: to make output string shorter we could probably
        //        remove dc=* items from it
        return rtrim(strtr(base64_encode($str), '+/', '-_'), '=');
    }

    /**
     * Decodes DN string encoded with _dn_encode()
     *
     * @param string $str Encoded HTML identifier string
     *
     * @return string DN string
     */
    static function dn_decode($str)
    {
        $str = str_pad(strtr($str, '-_', '+/'), strlen($str) % 4, '=', STR_PAD_RIGHT);
        return base64_decode($str);
    }
}
