<?php
/**
 * Addressbook - SQL backend
 *
 * @link http://www.egroupware.org
 * @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
 * @package addressbook
 * @copyright (c) 2006-12 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @version $Id$
 */

/**
 * SQL storage object of the adressbook
 */
class addressbook_sql extends so_sql_cf
{
	/**
	 * name of custom fields table
	 *
	 * @var string
	 */
	var $account_repository = 'sql';
	var $contact_repository = 'sql';
	var $grants;

	/**
	 * join to show only active account (and not already expired ones)
	 */
	const ACCOUNT_ACTIVE_JOIN = ' LEFT JOIN egw_accounts ON egw_addressbook.account_id=egw_accounts.account_id';
	/**
	 * filter to show only active account (and not already expired ones)
	 * UNIX_TIMESTAMP(NOW()) gets replaced with value of time() in the code!
	 */
	const ACOUNT_ACTIVE_FILTER = '(account_expires IS NULL OR account_expires = -1 OR account_expires > UNIX_TIMESTAMP(NOW()))';

	/**
	 * internal name of the id, gets mapped to uid
	 *
	 * @var string
	 */
	var $contacts_id='id';

	/**
	 * Name of the table for distribution lists
	 *
	 * @var string
	 */
	var $lists_table = 'egw_addressbook_lists';
	/**
	 * Name of the table with the members (contacts) of the distribution lists
	 *
	 * @var string
	 */
	var $ab2list_table = 'egw_addressbook2list';

	/**
	 * Constructor
	 *
	 * @param egw_db $db=null
	 */
	function __construct(egw_db $db=null)
	{
		parent::__construct('phpgwapi','egw_addressbook','egw_addressbook_extra','contact_',
			$extra_key='_name',$extra_value='_value',$extra_id='_id',$db);

		// Get custom fields from addressbook instead of phpgwapi
		$this->customfields = config::get_customfields('addressbook');

		if ($GLOBALS['egw_info']['server']['account_repository'])
		{
			$this->account_repository = $GLOBALS['egw_info']['server']['account_repository'];
		}
		elseif ($GLOBALS['egw_info']['server']['auth_type'])
		{
			$this->account_repository = $GLOBALS['egw_info']['server']['auth_type'];
		}
		if ($GLOBALS['egw_info']['server']['contact_repository'])
		{
			$this->contact_repository = $GLOBALS['egw_info']['server']['contact_repository'];
		}
	}

	/**
	 * Query organisations by given parameters
	 *
	 * @var array $param
	 * @var string $param[org_view] 'org_name', 'org_name,adr_one_location', 'org_name,org_unit' how to group
	 * @var int $param[owner] addressbook to search
	 * @var string $param[search] search pattern for org_name
	 * @var string $param[searchletter] letter the org_name need to start with
	 * @var array $param[col_filter] filter
	 * @var string $param[search] or'ed search pattern
	 * @var array $param[advanced_search] indicator that advanced search is active
	 * @var string $param[op] (operator like AND or OR; will be passed when advanced search is active)
	 * @var string $param[wildcard] (wildcard like % or empty or not set (for no wildcard); will be passed when advanced search is active)
	 * @var int $param[start]
	 * @var int $param[num_rows]
	 * @var string $param[sort] ASC or DESC
	 * @return array or arrays with keys org_name,count and evtl. adr_one_location or org_unit
	 */
	function organisations($param)
	{
		$filter = is_array($param['col_filter']) ? $param['col_filter'] : array();
		$op = 'OR';
		if (isset($param['op']) && !empty($param['op'])) $op = $param['op'];
		$advanced_search = false;
		if (isset($param['advanced_search']) && !empty($param['advanced_search'])) $advanced_search = true;
		$wildcard ='%';
		if ($advanced_search || (isset($param['wildcard']) && !empty($param['wildcard']))) $wildcard = ($param['wildcard']?$param['wildcard']:'');

		// fix cat_id filter to search in comma-separated multiple cats and return subcats
		if ((int)$filter['cat_id'])
		{
			$filter[] = $this->_cat_filter($filter['cat_id']);
			unset($filter['cat_id']);
		}
		// add filter for read ACL in sql, if user is NOT the owner of the addressbook
		if ($param['owner'] && $param['owner'] == $GLOBALS['egw_info']['user']['account_id'])
		{
			$filter['owner'] = $param['owner'];
		}
		else
		{
			// we have no private grants in addressbook at the moment, they have then to be added here too
			if ($param['owner'])
			{
				if (!$this->grants[(int) $filter['owner']]) return false;	// we have no access to that addressbook

				$filter['owner'] = $param['owner'];
				$filter['private'] = 0;
			}
			else	// search all addressbooks, incl. accounts
			{
				if ($this->account_repository != 'sql' && $this->contact_repository != 'sql-ldap')
				{
					$filter[] = $this->table_name.'.contact_owner != 0';	// in case there have been accounts in sql previously
				}
				$filter[] = "(".$this->table_name.".contact_owner=".(int)$GLOBALS['egw_info']['user']['account_id'].
					" OR contact_private=0 AND ".$this->table_name.".contact_owner IN (".
					implode(',',array_keys($this->grants))."))";
			}
		}
		if ($param['searchletter'])
		{
			$filter[] = 'org_name '.$this->db->capabilities[egw_db::CAPABILITY_CASE_INSENSITIV_LIKE].' '.$this->db->quote($param['searchletter'].'%');
		}
		else
		{
			$filter[] = "org_name != ''";// AND org_name IS NOT NULL";
		}
		$sort = $param['sort'] == 'DESC' ? 'DESC' : 'ASC';

		list(,$by) = explode(',',$param['org_view']);
		if (!$by)
		{
			$extra = array(
				'COUNT(DISTINCT egw_addressbook.contact_id) AS org_count',
				"COUNT(DISTINCT CASE WHEN org_unit IS NULL THEN '' ELSE org_unit END) AS org_unit_count",
				"COUNT(DISTINCT CASE WHEN adr_one_locality IS NULL THEN '' ELSE adr_one_locality END) AS adr_one_locality_count",
			);
			$append = "GROUP BY org_name ORDER BY org_name $sort";
		}
		else	// by adr_one_location or org_unit
		{
			// org total for more then one $by
			$by_expr = $by == 'org_unit_count' ? "COUNT(DISTINCT CASE WHEN org_unit IS NULL THEN '' ELSE org_unit END)" :
				"COUNT(DISTINCT CASE WHEN adr_one_locality IS NULL THEN '' ELSE adr_one_locality END)";
			$append = "GROUP BY org_name HAVING $by_expr > 1 ORDER BY org_name $sort";
			parent::search($param['search'],array('org_name'),$append,array(
				"NULL AS $by",
				'1 AS is_main',
				'COUNT(DISTINCT egw_addressbook.contact_id) AS org_count',
				"COUNT(DISTINCT CASE WHEN org_unit IS NULL THEN '' ELSE org_unit END) AS org_unit_count",
				"COUNT(DISTINCT CASE WHEN adr_one_locality IS NULL THEN '' ELSE adr_one_locality END) AS adr_one_locality_count",
			),$wildcard,false,$op/*'OR'*/,'UNION',$filter);
			// org by location
			$append = "GROUP BY org_name,$by ORDER BY org_name $sort,$by $sort";
			parent::search($param['search'],array('org_name'),$append,array(
				"CASE WHEN $by IS NULL THEN '' ELSE $by END AS $by",
				'0 AS is_main',
				'COUNT(DISTINCT egw_addressbook.contact_id) AS org_count',
				"COUNT(DISTINCT CASE WHEN org_unit IS NULL THEN '' ELSE org_unit END) AS org_unit_count",
				"COUNT(DISTINCT CASE WHEN adr_one_locality IS NULL THEN '' ELSE adr_one_locality END) AS adr_one_locality_count",
			),$wildcard,false,$op/*'OR'*/,'UNION',$filter);
			$append = "ORDER BY org_name $sort,is_main DESC,$by $sort";
		}
		$rows = parent::search($param['search'],array('org_name'),$append,$extra,$wildcard,false,$op/*'OR'*/,
			array($param['start'],$param['num_rows']),$filter);

		if (!$rows) return false;

		// query the values for *_count == 1, to display them instead
		$filter['org_name'] = $orgs = array();
		foreach($rows as $n => $row)
		{
			if ($row['org_unit_count'] == 1 || $row['adr_one_locality_count'] == 1)
			{
				$filter['org_name'][$row['org_name']] = $row['org_name'];	// use as key too to have every org only once
			}
			$org_key = $row['org_name'].($by ? '|||'.($row[$by] || $row[$by.'_count']==1 ? $row[$by] : '|||') : '');
			$orgs[$org_key] = $row;
		}
		unset($rows);

		if (count($filter['org_name']))
		{
			foreach((array) parent::search($criteria,array('org_name','org_unit','adr_one_locality'),'GROUP BY org_name,org_unit,adr_one_locality',
				'',$wildcard,false,$op/*'AND'*/,false,$filter) as $row)
			{
				$org_key = $row['org_name'].($by ? '|||'.$row[$by] : '');
				if ($orgs[$org_key]['org_unit_count'] == 1)
				{
					$orgs[$org_key]['org_unit'] = $row['org_unit'];
				}
				if ($orgs[$org_key]['adr_one_locality_count'] == 1)
				{
					$orgs[$org_key]['adr_one_locality'] = $row['adr_one_locality'];
				}
				if ($by && isset($orgs[$org_key = $row['org_name'].'||||||']))
				{
					if ($orgs[$org_key]['org_unit_count'] == 1)
					{
						$orgs[$org_key]['org_unit'] = $row['org_unit'];
					}
					if ($orgs[$org_key]['adr_one_locality_count'] == 1)
					{
						$orgs[$org_key]['adr_one_locality'] = $row['adr_one_locality'];
					}
				}
			}
		}
		return array_values($orgs);
	}

	/**
	 * searches db for rows matching searchcriteria
	 *
	 * '*' and '?' are replaced with sql-wildcards '%' and '_'
	 *
	 * For a union-query you call search for each query with $start=='UNION' and one more with only $order_by and $start set to run the union-query.
	 *
	 * @param array/string $criteria array of key and data cols, OR a SQL query (content for WHERE), fully quoted (!)
	 * @param boolean/string/array $only_keys=true True returns only keys, False returns all cols. or
	 *	comma seperated list or array of columns to return
	 * @param string $order_by='' fieldnames + {ASC|DESC} separated by colons ',', can also contain a GROUP BY (if it contains ORDER BY)
	 * @param string/array $extra_cols='' string or array of strings to be added to the SELECT, eg. "count(*) as num"
	 * @param string $wildcard='' appended befor and after each criteria
	 * @param boolean $empty=false False=empty criteria are ignored in query, True=empty have to be empty in row
	 * @param string $op='AND' defaults to 'AND', can be set to 'OR' too, then criteria's are OR'ed together
	 * @param mixed $start=false if != false, return only maxmatch rows begining with start, or array($start,$num), or 'UNION' for a part of a union query
	 * @param array $filter=null if set (!=null) col-data pairs, to be and-ed (!) into the query without wildcards
	 * @param string $join='' sql to do a join, added as is after the table-name, eg. ", table2 WHERE x=y" or
	 *	"LEFT JOIN table2 ON (x=y)", Note: there's no quoting done on $join!
	 * @param boolean $need_full_no_count=false If true an unlimited query is run to determine the total number of rows, default false
	 * @return boolean/array of matching rows (the row is an array of the cols) or False
	 */
	function &search($criteria,$only_keys=True,$order_by='',$extra_cols='',$wildcard='',$empty=False,$op='AND',$start=false,$filter=null,$join='',$need_full_no_count=false)
	{
		if ((int) $this->debug >= 4) echo '<p>'.__METHOD__.'('.array2string($criteria,true).','.array2string($only_keys).",'$order_by','$extra_cols','$wildcard','$empty','$op',$start,".array2string($filter,true).",'$join')</p>\n";
		//error_log(__METHOD__.'('.array2string($criteria,true).','.array2string($only_keys).",'$order_by','$extra_cols','$wildcard','$empty','$op',$start,".array2string($filter,true).",'$join')");

		$owner = isset($filter['owner']) ? $filter['owner'] : (isset($criteria['owner']) ? $criteria['owner'] : null);

		// fix cat_id criteria to search in comma-separated multiple cats and return subcats
		if (is_array($criteria) && ($cats = $criteria['cat_id']))
		{
			$criteria = array_merge($criteria, $this->_cat_search($criteria['cat_id']));
			unset($criteria['cat_id']);
		}
		// fix cat_id filter to search in comma-separated multiple cats and return subcats
		if (($cats = $filter['cat_id']))
		{
			if ($filter['cat_id'][0] == '!')
			{
				$filter['cat_id'] = substr($filter['cat_id'],1);
				$not = 'NOT';
			}
			$filter[] = $this->_cat_filter((int)$filter['cat_id'],$not);
			unset($filter['cat_id']);
		}

		// add filter for read ACL in sql, if user is NOT the owner of the addressbook
		if (isset($this->grants) && !(isset($filter['owner']) && $filter['owner'] == $GLOBALS['egw_info']['user']['account_id']))
		{
			// add read ACL for groupmembers (they have no
			if ($GLOBALS['egw_info']['user']['preferences']['common']['account_selection'] == 'groupmembers' &&
				(!isset($filter['owner']) || in_array('0',(array)$filter['owner'])))
			{
				$groupmembers = array();
				foreach($GLOBALS['egw']->accounts->memberships($GLOBALS['egw_info']['user']['account_id'],true) as $group_id)
				{
					if (($members = $GLOBALS['egw']->accounts->members($group_id,true)))
					{
						$groupmembers = array_merge($groupmembers,$members);
					}
				}
				$groupmember_sql = $this->db->expression($this->table_name, ' OR '.$this->table_name.'.',array(
					'account_id' => array_unique($groupmembers),
				));
			}
			// we have no private grants in addressbook at the moment, they have then to be added here too
			if (isset($filter['owner']))
			{
				// no grants for selected owner/addressbook
				if (!($filter['owner'] = array_intersect((array)$filter['owner'],array_keys($this->grants))))
				{
					if (!isset($groupmember_sql)) return false;
					$filter[] = substr($groupmember_sql,4);
					unset($filter['owner']);
				}
				// for an owner filter, which does NOT include current user, filter out private entries
				elseif (!in_array($GLOBALS['egw_info']['user']['account_id'],$filter['owner']))
				{
					$filter['private'] = 0;
				}
				// if multiple addressbooks (incl. current owner) are searched, we need full acl filter
				elseif(count($filter['owner']) > 1)
				{
					$filter[] = "($this->table_name.contact_owner=".(int)$GLOBALS['egw_info']['user']['account_id'].
						" OR contact_private=0 AND $this->table_name.contact_owner IN (".
						implode(',',array_keys($this->grants)).") $groupmember_sql OR $this->table_name.contact_owner IS NULL)";
				}
			}
			else	// search all addressbooks, incl. accounts
			{
				if ($this->account_repository != 'sql' && $this->contact_repository != 'sql-ldap')
				{
					$filter[] = $this->table_name.'.contact_owner != 0';	// in case there have been accounts in sql previously
				}
				$filter[] = "($this->table_name.contact_owner=".(int)$GLOBALS['egw_info']['user']['account_id'].
					" OR contact_private=0 AND $this->table_name.contact_owner IN (".
					implode(',',array_keys($this->grants)).") $groupmember_sql OR $this->table_name.contact_owner IS NULL)";
			}
		}
		if (isset($filter['list']))
		{
			$join .= " JOIN $this->ab2list_table ON $this->table_name.contact_id=$this->ab2list_table.contact_id AND list_id=".(int)$filter['list'];
			unset($filter['list']);
		}
		// add join to show only active accounts (only if accounts are shown and in sql and we not already join the accounts table, eg. used by admin)
		if (!$owner && substr($this->account_repository,0,3) == 'sql' &&
			strpos($join,$GLOBALS['egw']->accounts->backend->table) === false && !array_key_exists('account_id',$filter))
		{
			$join .= self::ACCOUNT_ACTIVE_JOIN;
			$filter[] = str_replace('UNIX_TIMESTAMP(NOW())',time(),self::ACOUNT_ACTIVE_FILTER);
		}
		if ($join || $criteria && is_string($criteria))	// search also adds a join for custom fields!
		{
			switch(gettype($only_keys))
			{
				case 'boolean':
					// Correctly handled by parent class
					break;
				case 'string':
					$only_keys = explode(',',$only_keys);
					// fall through
			}
			// postgres requires that expressions in order by appear in the columns of a distinct select
			if ($this->db->Type != 'mysql' && preg_match_all("/([a-zA-Z_.]+) *(<> *''|IS NULL|IS NOT NULL)? *(ASC|DESC)?(,|$)/ui",$order_by,$all_matches,PREG_SET_ORDER))
			{
				if (!is_array($extra_cols))	$extra_cols = $extra_cols ? explode(',',$extra_cols) : array();
				foreach($all_matches as $matches)
				{
					$table = '';
					$column = $matches[1];
					if (($key = array_search($column, $this->db_cols)) !== false) $column = $key;
					if (strpos($column,'.') === false)
					{
						$table = $column == $this->extra_value ? $this->extra_table : $this->table_name;
						if (isset($this->db_cols[$column]))
						{
							$table .= '.';
						}
						else
						{
							$table = '';
						}
					}
					$extra_cols[] = $table.$column.' '.$matches[2];
					//_debug_array($matches);
					if (!empty($order_by) && $table) // postgres requires explizit order by
					{
						$order_by = str_replace($matches[0],$table.$column.' '.$matches[2].' '.$matches[3].$matches[4],$order_by);
					}
				}
				//_debug_array($order_by); _debug_array($extra_cols);
			}
		}
		$rows =& parent::search($criteria,$only_keys,$order_by,$extra_cols,$wildcard,$empty,$op,$start,$filter,$join,$need_full_no_count);

		if ($start === false) $this->total = is_array($rows) ? count($rows) : 0;	// so_sql sets total only for $start !== false!

		return $rows;
	}

	/**
	 * fix cat_id filter to search in comma-separated multiple cats and return subcats
	 *
	 * @internal
	 * @param int $cat_id
	 * @return string sql to filter by given cat
	 */
	function _cat_filter($cat_id, $not='')
	{
		if (!is_object($GLOBALS['egw']->categories))
		{
			$GLOBALS['egw']->categories = CreateObject('phpgwapi.categories');
		}
		foreach($GLOBALS['egw']->categories->return_all_children((int)$cat_id) as $cat)
		{
			$cat_filter[] = $this->db->concat("','",cat_id,"','")." $not LIKE '%,$cat,%'";
		}
		$cfilter = '('.implode(' OR ',$cat_filter).')';
		if(!empty($not))
		{
			$cfilter = "( $cfilter OR cat_id IS NULL )";
		}
		return $cfilter;
	}

	/**
	 * fix cat_id criteria to search in comma-separated multiple cats
	 *
	 * @internal
	 * @param int/array $cats
	 * @return array of sql-strings to be OR'ed or AND'ed together
	 */
	function _cat_search($cats)
	{
		$cat_filter = array();
		foreach(is_array($cats) ? $cats : array($cats) as $cat)
		{
			if (is_numeric($cat)) $cat_filter[] = $this->db->concat("','",cat_id,"','")." LIKE '%,$cat,%'";
		}
		return $cat_filter;
	}

	/**
	 * Change the ownership of contacts owned by a given account
	 *
	 * @param int $account_id account-id of the old owner
	 * @param int $new_owner account-id of the new owner
	 */
	function change_owner($account_id,$new_owner)
	{
		if (!$new_owner)	// otherwise we would create an account (contact_owner==0)
		{
			die("socontacts_sql::change_owner($account_id,$new_owner) new owner must not be 0");
		}
		$this->db->update($this->table_name,array(
			'contact_owner' => $new_owner,
		),array(
			'contact_owner' => $account_id,
		),__LINE__,__FILE__);
	}

	/**
	 * Get the availible distribution lists for givens users and groups
	 *
	 * @param array $uids array of user or group id's for $uid_column='list_owners', or values for $uid_column,
	 * 	or whole where array: column-name => value(s) pairs
	 * @param string $uid_column='list_owner' column-name or null to use $uids as where array
	 * @param string $member_attr=null null: no members, 'contact_uid', 'contact_id', 'caldav_name' return members as that attribute
	 * @param boolean $limit_in_ab=false if true only return members from the same owners addressbook
	 * @return array with list_id => array(list_id,list_name,list_owner,...) pairs
	 */
	function get_lists($uids,$uid_column='list_owner',$member_attr=null,$limit_in_ab=false)
	{
		$lists = array();
		foreach($this->db->select($this->lists_table,'*',$uid_column?array($uid_column=>$uids):$uids,__LINE__,__FILE__,
			false,'ORDER BY list_owner<>'.(int)$GLOBALS['egw_info']['user']['account_id'].',list_name') as $row)
		{
			if ($member_attr) $row['members'] = array();
			$lists[$row['list_id']] = $row;
		}
		if ($lists && $member_attr && in_array($member_attr,array('contact_id','contact_uid','caldav_name')))
		{
			foreach($this->db->select($this->ab2list_table,"$this->ab2list_table.list_id,$this->table_name.$member_attr",
				$this->db->expression($this->ab2list_table, $this->ab2list_table.'.', array('list_id'=>array_keys($lists))),
				__LINE__,__FILE__,false,$member_attr=='contact_id' ? '' :
				'',false,0,"JOIN $this->table_name ON $this->ab2list_table.contact_id=$this->table_name.contact_id".
				($limit_in_ab?" JOIN $this->lists_table ON $this->lists_table.list_id=$this->ab2list_table.list_id AND $this->lists_table.list_owner=$this->table_name.contact_owner":'')) as $row)
			{
				$lists[$row['list_id']]['members'][] = $row[$member_attr];
			}
		}
		//error_log(__METHOD__.'('.array2string($uids).", '$uid_column', '$member_attr') returning ".array2string($lists));
		return $lists;
	}

	/**
	 * Adds / updates a distribution list
	 *
	 * @param string|array $keys list-name or array with column-name => value pairs to specify the list
	 * @param int $owner user- or group-id
	 * @param array $contacts=array() contacts to add (only for not yet existing lists!)
	 * @param array &$data=array() values for keys 'list_uid', 'list_carddav_name', 'list_name'
	 * @return int|boolean integer list_id or false on error
	 */
	function add_list($keys,$owner,$contacts=array(),array &$data=array())
	{
		//error_log(__METHOD__.'('.array2string($keys).", $owner, ".array2string($contacts).', '.array2string($data).') '.function_backtrace());
		if (!$keys && !$data || !(int)$owner) return false;

		if ($keys && !is_array($keys)) $keys = array('list_name' => $keys);
		if ($keys)
		{
			$keys['list_owner'] = $owner;
		}
		else
		{
			$data['list_owner'] = $owner;
		}
		if (!$keys || !($list_id = $this->db->select($this->lists_table,'list_id',$keys,__LINE__,__FILE__)->fetchColumn()))
		{
			$data['list_created'] = time();
			$data['list_creator'] = $GLOBALS['egw_info']['user']['account_id'];
		}
		else
		{
			$data[] = 'list_etag=list_etag+1';
		}
		$data['list_modified'] = time();
		$data['list_modifier'] = $GLOBALS['egw_info']['user']['account_id'];
		if (!$data['list_id']) unset($data['list_id']);

		if (!$this->db->insert($this->lists_table,$data,$keys,__LINE__,__FILE__)) return false;

		if (!$list_id && ($list_id = $this->db->get_last_insert_id($this->lists_table,'list_id')) &&
			(!isset($data['list_uid']) || !isset($data['list_carddav_name'])))
		{
			$update = array();
			if (!isset($data['list_uid']))
			{
				$update['list_uid'] = $data['list_uid'] = common::generate_uid('addresbook-lists', $list_id);
			}
			if (!isset($data['list_carddav_name']))
			{
				$update['list_carddav_name'] = $data['list_carddav_name'] = $data['list_uid'].'.vcf';
			}
			$this->db->update($this->lists_table,$update,array('list_id'=>$list_id),__LINE__,__FILE__);

			$this->add2list($list_id,$contacts,array());
		}
		if ($keys) $data += $keys;
		//error_log(__METHOD__.'('.array2string($keys).", $owner, ...) data=".array2string($data).' returning '.array2string($list_id));
		return $list_id;
	}

	/**
	 * Adds contact(s) to a distribution list
	 *
	 * @param int|array $contact contact_id(s)
	 * @param int $list list-id
	 * @param array $existing=null array of existing contact-id(s) of list, to not reread it, eg. array()
	 * @return false on error
	 */
	function add2list($contact,$list,array $existing=null)
	{
		if (!(int)$list || !is_array($contact) && !(int)$contact) return false;

		if (!is_array($existing))
		{
			$existing = array();
			foreach($this->db->select($this->ab2list_table,'contact_id',array('list_id'=>$list),__LINE__,__FILE__) as $row)
			{
				$existing[] = $row['contact_id'];
			}
		}
		if (!($to_add = array_diff((array)$contact,$existing)))
		{
			return true;	// no need to insert it, would give sql error
		}
		foreach($to_add as $contact)
		{
			$this->db->insert($this->ab2list_table,array(
				'contact_id' => $contact,
				'list_id' => $list,
				'list_added' => time(),
				'list_added_by' => $GLOBALS['egw_info']['user']['account_id'],
			),array(),__LINE__,__FILE__);
		}
		// update etag
		return $this->db->update($this->lists_table,array(
			'list_etag=list_etag+1',
			'list_modified' => time(),
			'list_modifier' => $GLOBALS['egw_info']['user']['account_id'],
		),array(
			'list_id' => $list,
		),__LINE__,__FILE__);
	}

	/**
	 * Removes one contact from distribution list(s)
	 *
	 * @param int|array $contact contact_id(s)
	 * @param int $list=null list-id or null to remove from all lists
	 * @return false on error
	 */
	function remove_from_list($contact,$list=null)
	{
		if (!(int)$list && !is_null($list) || !is_array($contact) && !(int)$contact) return false;

		$where = array(
			'contact_id' => $contact,
		);
		if (!is_null($list))
		{
			$where['list_id'] = $list;
		}
		else
		{
			$list = array();
			foreach($this->db->select($this->ab2list_table,'list_id',$where,__LINE__,__FILE__) as $row)
			{
				$list[] = $row['list_id'];
			}
		}
		if (!$this->db->delete($this->ab2list_table,$where,__LINE__,__FILE__))
		{
			return false;
		}
		foreach((array)$list as $list_id)
		{
			$this->db->update($this->lists_table,array(
				'list_etag=list_etag+1',
				'list_modified' => time(),
				'list_modifier' => $GLOBALS['egw_info']['user']['account_id'],
			),array(
				'list_id' => $list_id,
			),__LINE__,__FILE__);
		}
		return true;
	}

	/**
	 * Deletes a distribution list (incl. it's members)
	 *
	 * @param int/array $list list_id(s)
	 * @return number of members deleted or false if list does not exist
	 */
	function delete_list($list)
	{
		if (!$this->db->delete($this->lists_table,array('list_id' => $list),__LINE__,__FILE__)) return false;

		$this->db->delete($this->ab2list_table,array('list_id' => $list),__LINE__,__FILE__);

		return $this->db->affected_rows();
	}

	/**
	 * Get ctag (max list_modified as timestamp) for lists
	 *
	 * @param int|array $owner=null null for all lists user has access too
	 * @return int
	 */
	function lists_ctag($owner=null)
	{
		if (is_null($owner)) $owner = array_keys($this->grants);

		if (!($modified = $this->db->select($this->lists_table,'MAX(list_modified)',array('list_owner'=>$owner),
			__LINE__,__FILE__)->fetchColumn()))
		{
			return 0;
		}
		return $this->db->from_timestamp($modified);
	}

	/**
	 * Reads a contact, reimplemented to use the uid, if a non-numeric key is given
	 *
	 * @param int|string|array $keys
	 * @param string|array $extra_cols
	 * @param string $join
	 * @return array|boolean
	 */
	function read($keys,$extra_cols='',$join='')
	{
		if (isset($GLOBALS['egw_info']['user']['preferences']['syncml']['minimum_uid_length'])) {
			$minimum_uid_length = $GLOBALS['egw_info']['user']['preferences']['syncml']['minimum_uid_length'];
		} else {
			$minimum_uid_length = 8;
		}

		if (!is_array($keys) && !is_numeric($keys))
		{
			$keys = array('contact_uid' => $keys);
		}
		$contact = parent::read($keys,$extra_cols,$join);

		// Change autoinc_id to match $this->db_cols
		$this->autoinc_id = $this->db_cols[$this->autoinc_id];
		if(($id = (int)$this->data[$this->autoinc_id]) && $cfs = $this->read_customfields($keys)) {
			if (is_array($cfs[$id])) $contact = array_merge($contact,$cfs[$id]);
		}
		$this->autoinc_id = array_search($this->autoinc_id, $this->db_cols);

		// enforce a minium uid strength
		if (is_array($contact) && (!isset($contact['uid'])
				|| strlen($contact['uid']) < $minimum_uid_length)) {
			parent::update(array('uid' => common::generate_uid('addressbook',$contact['id'])));
		}
		return $contact;
	}

	/**
	 * Saves a contact, reimplemented to check a given etag and set a uid
	 *
	 * @param array $keys if given $keys are copied to data before saveing => allows a save as
	 * @param string|array $extra_where=null extra where clause, eg. to check the etag, returns 'nothing_affected' if not affected rows
	 * @return int 0 on success and errno != 0 else
	 */
	function save($keys=null)
	{
		if (isset($GLOBALS['egw_info']['user']['preferences']['syncml']['minimum_uid_length'])) {
			$minimum_uid_length = $GLOBALS['egw_info']['user']['preferences']['syncml']['minimum_uid_length'];
		} else {
			$minimum_uid_length = 8;
		}

		if (is_array($keys) && count($keys)) $this->data_merge($keys);

		$new_entry = !$this->data['id'];

		if (isset($this->data['etag']))		// do we have an etag in the data to write
		{
			$etag = $this->data['etag'];
			unset($this->data['etag']);
			if (!($err = parent::save(array('contact_etag=contact_etag+1'),array('contact_etag' => $etag))))
			{
				$this->data['etag'] = $etag+1;
			}
			else
			{
				$this->data['etag'] = $etag;
			}
		}
		else
		{
			unset($this->data['etag']);
			if (!($err = parent::save(array('contact_etag=contact_etag+1'))) && $new_entry)
			{
				$this->data['etag'] = 0;
			}
		}

		$update = array();
		// enforce a minium uid strength
		if (!isset($this->data['uid']) || strlen($this->data['uid']) < $minimum_uid_length)
		{
			$update['uid'] = common::generate_uid('addressbook',$this->data['id']);
			//echo "<p>set uid={$this->data['uid']}, etag={$this->data['etag']}</p>";
		}
		// set carddav_name, if not given by caller
		if (empty($this->data['carddav_name']))
		{
			$update['carddav_name'] = $this->data['id'].'.vcf';
		}
		if (!$err && $update)
		{
			parent::update($update);
		}
		return $err;
	}


	/**
	 * Read data of a distribution list
	 *
	 * @param int $list list_id
	 * @return array of data or false if list does not exist
	 */
	function read_list($list)
	{
		if (!$list) return false;

		return $this->db->select($this->lists_table,'*',array('list_id'=>$list),__LINE__,__FILE__)->fetch();
	}

	/**
	 * saves custom field data
	 * Re-implemented to deal with extra contact_owner column
	 *
	 * @param array $data data to save (cf's have to be prefixed with self::CF_PREFIX = #)
	 * @return bool false on success, errornumber on failure
	 */
	function save_customfields($data)
	{
		foreach ((array)$this->customfields as $name => $options)
		{
			if (!isset($data[$field = $this->get_cf_field($name)])) continue;

			$where = array(
					$this->extra_id    => $data['id'],
					$this->extra_key   => $name,
				);
			$is_multiple = $this->is_multiple($name);

			// we explicitly need to delete fields, if value is empty or field allows multiple values or we have no unique index
			if(empty($data[$field]) || $is_multiple || !$this->extra_has_unique_index)
			{
				$this->db->delete($this->extra_table,$where,__LINE__,__FILE__,$this->app);
				if (empty($data[$field])) continue;     // nothing else to do for empty values
			}
			foreach($is_multiple && !is_array($data[$field]) ? explode(',',$data[$field]) : (array)$data[$field] as $value)
			{
				if (!$this->db->insert($this->extra_table,array($this->extra_value => $value, 'contact_owner' => $data['owner']),$where,__LINE__,__FILE__,$this->app))
				{
					return $this->db->Errno;
				}
			}
		}
		return false;   // no error
	}

	/**
	* Deletes custom field data
	* Implemented to deal with LDAP backend, which saves CFs in SQL, but the account record is in LDAP
	*/
	function delete_customfields($data)
	{
		$this->db->delete($this->extra_table,$data,__LINE__,__FILE__);
	}
}