<?php
/**
* @version	$Id: dbitem.php 13349 2010-04-06 12:44:19Z alex $
* @package	In-Portal
* @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
* @license      GNU/GPL
* In-Portal is Open Source software.
* This means that this software may have been modified pursuant
* the GNU General Public License, and as distributed it includes
* or is derivative of works licensed under the GNU General Public License
* or other free or open source software licenses.
* See http://www.in-portal.org/license for copyright notices and details.
*/

defined('FULL_PATH') or die('restricted access!');

/**
* DBItem
*
* Desciption
* @package kernel4
*/
class kDBItem extends kDBBase {

	/**
	* Description
	*
	* @var array Associative array of current item' field values
	* @access public
	*/
	var $FieldValues;

	/**
	 * Unformatted field values, before parse
	 *
	 * @var Array
	 * @access private
	 */
	var $DirtyFieldValues = Array();

	/**
	 * Holds item values after loading (not affected by submit)
	 *
	 * @var Array
	 * @access private
	 */
	var $OriginalFieldValues = Array ();

	var $FieldErrors;

	var $ErrorMsgs = Array();

	/**
	* If set to true, Update will skip Validation before running
	*
	* @var array Associative array of current item' field values
	* @access public
	*/
	var $IgnoreValidation = false;

	var $Loaded = false;

	/**
	* Holds item' primary key value
	*
	* @var int Value of primary key field for current item
	* @access public
	*/
	var $ID;

	/**
	 * This object is used in cloning operations
	 *
	 * @var bool
	 */
	var $inCloning = false;

	function kDBItem()
	{
		parent::kDBBase();
		$this->ErrorMsgs['required'] = '!la_err_required!'; //'Field is required';
		$this->ErrorMsgs['unique'] = '!la_err_unique!'; //'Field value must be unique';
		$this->ErrorMsgs['value_out_of_range'] = '!la_err_value_out_of_range!'; //'Field is out of range, possible values from %s to %s';
		$this->ErrorMsgs['length_out_of_range'] = '!la_err_length_out_of_range!'; //'Field is out of range';
		$this->ErrorMsgs['bad_type'] = '!la_err_bad_type!'; //'Incorrect data format, please use %s';
		$this->ErrorMsgs['invalid_format'] = '!la_err_invalid_format!'; //'Incorrect data format, please use %s';
		$this->ErrorMsgs['bad_date_format'] = '!la_err_bad_date_format!'; //'Incorrect date format, please use (%s) ex. (%s)';
		$this->ErrorMsgs['primary_lang_required'] = '!la_err_primary_lang_required!';
	}

	function SetDirtyField($field_name, $field_value)
	{
		$this->DirtyFieldValues[$field_name] = $field_value;
	}

	function GetDirtyField($field_name)
	{
		return $this->DirtyFieldValues[$field_name];
	}

	function GetOriginalField($field_name, $formatted = false, $format=null)
	{
		if (array_key_exists($field_name, $this->OriginalFieldValues)) {
			// item was loaded before
			$value = $this->OriginalFieldValues[$field_name];
		}
		else {
			// no original fields -> use default field value
			$value = $this->Fields[$field_name]['default'];
		}

		if (!$formatted) {
			return $value;
		}

		$options = $this->GetFieldOptions($field_name);
		$res = $value;
		if (array_key_exists('formatter', $options)) {
			$formatter =& $this->Application->recallObject($options['formatter']);
			/* @var $formatter kFormatter */

			$res = $formatter->Format($value, $field_name, $this, $format);
		}
		return $res;
	}

	/**
	 * Sets original field value (useful for custom virtual fields)
	 *
	 * @param string $field_name
	 */
	function SetOriginalField($field_name, $field_value)
	{
		$this->OriginalFieldValues[$field_name] = $field_value;
	}

	/**
	 * Set's default values for all fields
	 *
	 * @param bool $populate_ml_fields create all ml fields from db in config or not
	 *
	 * @access public
	 */
	function SetDefaultValues($populate_ml_fields = false)
	{
		parent::SetDefaultValues($populate_ml_fields);
		if ($populate_ml_fields) {
			$this->PopulateMultiLangFields();
		}

		foreach ($this->Fields as $field => $params) {
			if ( isset($params['default']) ) {
				$this->SetDBField($field, $params['default']);
			}
			else {
				$this->SetDBField($field, NULL);
			}
		}
	}

	/**
	* Sets current item field value
	* (applies formatting)
	*
	* @access public
	* @param string $name Name of the field
	* @param mixed $value Value to set the field to
	* @return void
	*/
	function SetField($name,$value)
	{
		$options = $this->GetFieldOptions($name);
		$parsed = $value;
		if ($value == '') {
			$parsed = NULL;
		}

		// kFormatter is always used, to make sure, that numeric value is converted to normal representation
		// according to regional format, even when formatter is not set (try seting format to 1.234,56 to understand why)
		$formatter =& $this->Application->recallObject(isset($options['formatter']) ? $options['formatter'] : 'kFormatter');
		$parsed = $formatter->Parse($value, $name, $this);

		$this->SetDBField($name,$parsed);
	}

	/**
	* Sets current item field value
	* (doesn't apply formatting)
	*
	* @access public
	* @param string $name Name of the field
	* @param mixed $value Value to set the field to
	* @return void
	*/
	function SetDBField($name,$value)
	{
		$this->FieldValues[$name] = $value;
		/*if (isset($this->Fields[$name]['formatter'])) {
			$formatter =& $this->Application->recallObject($this->Fields[$name]['formatter']);
			$formatter->UpdateSubFields($name, $value, $this->Fields[$name], $this);
		}*/
	}

	/**
	 * Set's field error, if pseudo passed not found then create it with message text supplied.
	 * Don't owerrite existing pseudo translation.
	 *
	 * @param string $field
	 * @param string $pseudo
	 * @param string $error_label
	 *
	 * @return bool
	 */
	function SetError($field, $pseudo, $error_label = null, $error_params = null)
	{
		$error_field = isset($this->Fields[$field]['error_field']) ? $this->Fields[$field]['error_field'] : $field;
		if (isset($this->FieldErrors[$error_field]['pseudo'])) {
			// don't set more then one error on field
			return false;
		}

		$this->FieldErrors[$error_field]['pseudo'] = $pseudo;

		if (isset($error_params)) {
			if (array_key_exists('value', $error_params)) {
				$this->FieldErrors[$error_field]['value'] = $error_params['value'];
				unset($error_params['value']);
			}

			// additional params, that helps to determine error sources
			$this->FieldErrors[$error_field]['params'] = $error_params;
		}

		if (isset($error_label) && !isset($this->ErrorMsgs[$pseudo])) {
			// label for error (only when not already set)
			$this->ErrorMsgs[$pseudo] = (substr($error_label, 0, 1) == '+') ? substr($error_label, 1) : '!'.$error_label.'!';
		}

		return true;
	}

	/**
	* Return current item' field value by field name
	* (doesn't apply formatter)
	*
	* @access public
	* @param string $name field name to return
	* @return mixed
	*/
	function GetDBField($name)
	{
		/*if (!array_key_exists($name, $this->FieldValues) && defined('DEBUG_MODE') && DEBUG_MODE) {
			$this->Application->Debugger->appendTrace();
		}*/

		return $this->FieldValues[$name];
	}

	function HasField($name)
	{
		return isset($this->FieldValues[$name]);
	}

	function GetFieldValues()
	{
		return $this->FieldValues;
	}

	/**
	* Sets item' fields corresponding to elements in passed $hash values.
	*
	* The function sets current item fields to values passed in $hash, by matching $hash keys with field names
	* of current item. If current item' fields are unknown {@link kDBItem::PrepareFields()} is called before acutally setting the fields
	*
	* @access public
	* @param Array $hash
	* @param Array $set_fields Optional param, field names in target object to set, other fields will be skipped
	* @return void
	*/
	function SetFieldsFromHash($hash, $set_fields = null)
	{
		// used in formatter which work with multiple fields together
		foreach($hash as $field_name => $field_value) {
			if (is_numeric($field_name) || !array_key_exists($field_name, $this->Fields)) {
				continue;
			}

			if (is_array($set_fields) && !in_array($field_name, $set_fields)) {
				continue;
			}

			$this->SetDirtyField($field_name, $field_value);
		}

		// formats all fields using associated formatters
		foreach ($hash as $field_name => $field_value)
		{
			if (is_numeric($field_name) || !array_key_exists($field_name, $this->Fields)) {
				continue;
			}

			if (is_array($set_fields) && !in_array($field_name, $set_fields)) {
				continue;
			}

			$this->SetField($field_name,$field_value);
		}
	}

	function SetDBFieldsFromHash($hash, $set_fields = null)
	{
		foreach ($hash as $field_name => $field_value) {
			if (is_numeric($field_name) || !array_key_exists($field_name, $this->Fields)) {
				continue;
			}

			if (is_array($set_fields) && !in_array($field_name, $set_fields)) {
				continue;
			}

			$this->SetDBField($field_name, $field_value);
		}
	}

	/**
	* Returns part of SQL WHERE clause identifing the record, ex. id = 25
	*
	* @access public
	* @param string $method Child class may want to know who called GetKeyClause, Load(), Update(), Delete() send its names as method
	* @param Array $keys_hash alternative, then item id, keys hash to load item by
	* @return void
	* @see kDBItem::Load()
	* @see kDBItem::Update()
	* @see kDBItem::Delete()
	*/
	function GetKeyClause($method=null, $keys_hash = null)
	{
		if (!isset($keys_hash)) {
			$keys_hash = Array ($this->IDField => $this->ID);
		}

		$ret = '';

		foreach ($keys_hash as $field => $value) {
			if (!preg_match('/\./', $field)) {
				$ret .= '(`' . $this->TableName . '`.' . $field . ' = ' . $this->Conn->qstr($value) . ') AND ';
			}
			else {
				$ret .= '(' . $field . ' = ' . $this->Conn->qstr($value) . ') AND ';
			}
		}

		return substr($ret, 0, -5);
	}

	/**
	* Loads item from the database by given id
	*
	* @access public
	* @param mixed $id item id of keys->values hash to load item by
	* @param string $id_field_name Optional parameter to load item by given Id field
	* @return bool True if item has been loaded, false otherwise
	*/
	function Load($id, $id_field_name = null)
	{
		if ( isset($id_field_name) ) {
			$this->SetIDField($id_field_name); // set new IDField
		}

		$keys_sql = '';
		if (is_array($id)) {
			$keys_sql = $this->GetKeyClause('load', $id);
		}
		else {
			$this->setID($id);
			$keys_sql = $this->GetKeyClause('load');
		}

		if ( isset($id_field_name) ) {
			// restore original IDField from unit config
			$this->setIDField( $this->Application->getUnitOption($this->Prefix, 'IDField') );
		}

		if (($id === false) || !$keys_sql) {
			return $this->Clear();
		}

		if (!$this->raiseEvent('OnBeforeItemLoad', $id)) {
			return false;
		}

		$q = $this->GetSelectSQL() . ' WHERE ' . $keys_sql;
		$field_values = $this->Conn->GetRow($q);

		if ($field_values) {
			$this->FieldValues = array_merge_recursive2($this->FieldValues, $field_values);
			$this->OriginalFieldValues = $this->FieldValues;
		}
		else {
			return $this->Clear();
		}

		if (is_array($id) || isset($id_field_name)) {
			$this->setID($this->FieldValues[$this->IDField]);
		}

		$this->UpdateFormattersSubFields(); // used for updating separate virtual date/time fields from DB timestamp (for example)

		$this->raiseEvent('OnAfterItemLoad', $this->GetID());
		$this->Loaded = true;

		return true;
	}

	/**
	* Builds select sql, SELECT ... FROM parts only
	*
	* @access public
	* @return string
	*/
	function GetSelectSQL()
	{
		$sql = $this->addCalculatedFields($this->SelectClause);
		return parent::GetSelectSQL($sql);
	}

	function UpdateFormattersMasterFields()
	{
		foreach ($this->Fields as $field => $options) {
			if (isset($options['formatter'])) {
				$formatter =& $this->Application->recallObject($options['formatter']);
				$formatter->UpdateMasterFields($field, $this->GetDBField($field), $options, $this);
			}
		}
	}

	/**
	 * Allows to skip certain fields from getting into sql queries
	 *
	 * @param string $field_name
	 * @param mixed $force_id
	 * @return bool
	 */
	function skipField($field_name, $force_id = false)
	{
		$skip = false;

		// 1. skipping 'virtual' field
		$skip = $skip || array_key_exists($field_name, $this->VirtualFields);

		// 2. don't write empty field value to db, when "skip_empty" option is set
		$field_value = array_key_exists($field_name, $this->FieldValues) ? $this->FieldValues[$field_name] : false;

		if (array_key_exists($field_name, $this->Fields)) {
			$skip_empty = array_key_exists('skip_empty', $this->Fields[$field_name]) ? $this->Fields[$field_name]['skip_empty'] : false;
		}
		else {
			// field found in database, but not declared in unit config
			$skip_empty = false;
		}

		$skip = $skip || (!$field_value && $skip_empty);

		// 3. skipping field not in Fields (nor virtual, nor real)
		$skip = $skip || !array_key_exists($field_name, $this->Fields);

		return $skip;
	}

	/**
	* Updates previously loaded record with current item' values
	*
	* @access public
	* @param int Primery Key Id to update
	* @return bool
	*/
	function Update($id = null, $system_update = false)
	{
		if (isset($id)) {
			$this->setID($id);
		}

		if (!$this->raiseEvent('OnBeforeItemUpdate')) {
			return false;
		}

		if (!isset($this->ID)) {
			// ID could be set inside OnBeforeItemUpdate event, so don't combine this check with previous one
			return false;
		}

		// validate before updating
		if (!$this->Validate()) {
			return false;
		}

	    if (!$this->FieldValues) {
	    	// nothing to update
	    	return true;
	    }

	    $sql = '';

	    foreach ($this->FieldValues as $field_name => $field_value) {
	    	if ($this->skipField($field_name)) {
	    		continue;
	    	}

	    	if ( is_null($field_value) ) {
	    		if (array_key_exists('not_null', $this->Fields[$field_name]) && $this->Fields[$field_name]['not_null']) {
	    			// "kFormatter::Parse" methods converts empty values to NULL and for
	    			// not-null fields they are replaced with default value here
	    			$field_value = $this->Fields[$field_name]['default'];
	    		}
	    	}

	    	$sql .= '`' . $field_name . '` = ' . $this->Conn->qstr($field_value) . ', ';
	   	}

	   	$sql = 'UPDATE ' . $this->TableName . '
	   			SET ' . substr($sql, 0, -2) . '
	   			WHERE ' . $this->GetKeyClause('update');

	    if ($this->Conn->ChangeQuery($sql) === false) {
	    	// there was and sql error
	    	return false;
	    }

		$affected = $this->Conn->getAffectedRows();
		if (!$system_update && $affected == 1) {
			$this->setModifiedFlag(clUPDATE);
		}

		$this->saveCustomFields();
	    $this->raiseEvent('OnAfterItemUpdate');
	    $this->Loaded = true;

	    if ($this->mode != 't') {
			$this->Application->resetCounters($this->TableName);
		}

		return true;
	}

	function ValidateField($field)
	{
		$options = $this->Fields[$field];

		/*if (isset($options['formatter'])) {
			$formatter =& $this->Application->recallObject($options['formatter']);
			$formatter->UpdateMasterFields($field, $this->GetDBField($field), $options, $this);
		}*/

		$error_field = isset($options['error_field']) ? $options['error_field'] : $field;
		$res = !isset($this->FieldErrors[$error_field]['pseudo']) || !$this->FieldErrors[$error_field]['pseudo'];

		$res = $res && $this->ValidateRequired($field, $options);
		$res = $res && $this->ValidateType($field, $options);
		$res = $res && $this->ValidateRange($field, $options);
		$res = $res && $this->ValidateUnique($field, $options);
		$res = $res && $this->CustomValidation($field, $options);

		return $res;
	}

	/**
	 * Validate all item fields based on
	 * constraints set in each field options
	 * in config
	 *
	 * @return bool
	 * @access private
	 */
	function Validate()
	{
		$this->UpdateFormattersMasterFields(); //order is critical - should be called BEFORE checking errors

		if ($this->IgnoreValidation) {
			return true;
		}

		// will apply any custom validation to the item
		$this->raiseEvent('OnBeforeItemValidate');

		$global_res = true;
		foreach ($this->Fields as $field => $params) {
			$res = $this->ValidateField($field);


			$global_res = $global_res && $res;
		}

		if (!$global_res && $this->Application->isDebugMode()) {
			$error_msg = '	Validation failed in prefix <strong>'.$this->Prefix.'</strong>,
							FieldErrors follow (look at items with <strong>"pseudo"</strong> key set)<br />
							You may ignore this notice if submitted data really has a validation error';
			trigger_error(trim($error_msg), E_USER_NOTICE);
			$this->Application->Debugger->dumpVars($this->FieldErrors);
		}

		if ($global_res) {
			// no validation errors
			$this->raiseEvent('OnAfterItemValidate');
		}

		return $global_res;
	}

	/**
	 * Check field value by user-defined alghoritm
	 *
	 * @param string $field field name
	 * @param Array $params field options from config
	 * @return bool
	 */
	function CustomValidation($field, $params)
	{
		return true;
	}

	/**
	 * Check if item has errors
	 *
	 * @param Array $skip_fields fields to skip during error checking
	 * @return bool
	 */
	function HasErrors($skip_fields)
	{
		$global_res = false;

		foreach ($this->Fields as $field => $field_params) {
			// If Formatter has set some error messages during values parsing
			if ( !( in_array($field, $skip_fields) ) &&
				isset($this->FieldErrors[$field]['pseudo']) && $this->FieldErrors[$field] != '') {
				$global_res = true;
			}
		}
		return $global_res;
	}

	/**
	 * Check if value in field matches field type specified in config
	 *
	 * @param string $field field name
	 * @param Array $params field options from config
	 * @return bool
	 */
	function ValidateType($field, $params)
	{
		$res = true;
		$val = $this->FieldValues[$field];
		if ( 	$val != '' &&
					isset($params['type']) &&
					preg_match("#int|integer|double|float|real|numeric|string#", $params['type'])
				) {
			if ($params['type'] == 'numeric') {
				trigger_error('Invalid field type <strong>'.$params['type'].'</strong> (in ValidateType method), please use <strong>float</strong> instead', E_USER_NOTICE);
				$params['type'] = 'float';
			}
			$res = is_numeric($val);
			if ($params['type']=='string' || $res) {
				$f = 'is_'.$params['type'];
				settype($val, $params['type']);
				$res = $f($val) && ($val == $this->FieldValues[$field]);
			}
			if (!$res) {
				$this->SetError($field, 'bad_type', null, $params['type']);
			}
		}
		return $res;
	}

	/**
	 * Check if value is set for required field
	 *
	 * @param string $field field name
	 * @param Array $params field options from config
	 * @return bool
	 * @access private
	 */
	function ValidateRequired($field, $params)
	{
		$res = true;
		if (isset($params['required']) && $params['required']) {
			$check_value = $this->FieldValues[$field];
			if ($this->Application->ConfigValue('TrimRequiredFields')) {
				$check_value = trim($check_value);
			}
			$res = ((string)$check_value != '');
		}

		if (!$res) {
			$this->SetError($field, 'required');
		}

		return $res;
	}

	/**
	 * Validates that current record has unique field combination among other table records
	 *
	 * @param string $field field name
	 * @param Array $params field options from config
	 * @return bool
	 * @access private
	 */
	function ValidateUnique($field, $params)
	{
		$res = true;
		$unique_fields = getArrayValue($params,'unique');
		if($unique_fields !== false)
		{
			$where = Array();
			array_push($unique_fields,$field);
			foreach($unique_fields as $unique_field)
			{
				// if field is not empty or if it is required - we add where condition
				if ((string)$this->GetDBField($unique_field) != '' || (isset($this->Fields[$unique_field]['required']) && $this->Fields[$unique_field]['required'])) {
					$where[] = '`'.$unique_field.'` = '.$this->Conn->qstr( $this->GetDBField($unique_field) );
				}
				else {
					// not good if we check by less fields than indicated
					return true;
				}
			}
			// This can ONLY happen if all unique fields are empty and not required.
			// In such case we return true, because if unique field is not required there may be numerous empty values
//			if (!$where) return true;

			$sql = 'SELECT COUNT(*) FROM %s WHERE ('.implode(') AND (',$where).') AND ('.$this->IDField.' <> '.(int)$this->ID.')';

			$res_temp = $this->Conn->GetOne( str_replace('%s', $this->TableName, $sql) );

			$current_table_only = getArrayValue($params, 'current_table_only'); // check unique record only in current table
			$res_live = $current_table_only ? 0 : $this->Conn->GetOne( str_replace('%s', $this->Application->GetLiveName($this->TableName), $sql) );

			$res = ($res_temp == 0) && ($res_live == 0);

			if (!$res) {
				$this->SetError($field, 'unique');
			}
		}
		return $res;
	}

	/**
	 * Check if field value is in range specified in config
	 *
	 * @param string $field field name
	 * @param Array $params field options from config
	 * @return bool
	 * @access private
	 */
	function ValidateRange($field, $params)
	{
		$res = true;
		$val = $this->FieldValues[$field];

		if ( isset($params['type']) && preg_match("#int|integer|double|float|real#", $params['type']) && strlen($val) > 0 ) {
			if ( isset($params['max_value_inc'])) {
				$res = $res && $val <= $params['max_value_inc'];
				$max_val = $params['max_value_inc'].' (inclusive)';
			}
			if ( isset($params['min_value_inc'])) {
				$res = $res && $val >= $params['min_value_inc'];
				$min_val = $params['min_value_inc'].' (inclusive)';
			}
			if ( isset($params['max_value_exc'])) {
				$res = $res && $val < $params['max_value_exc'];
				$max_val = $params['max_value_exc'].' (exclusive)';
			}
			if ( isset($params['min_value_exc'])) {
				$res = $res && $val > $params['min_value_exc'];
				$min_val = $params['min_value_exc'].' (exclusive)';
			}
		}
		if (!$res) {
			if ( !isset($min_val) ) $min_val = '-&infin;';
			if ( !isset($max_val) ) $max_val = '&infin;';

			$this->SetError($field, 'value_out_of_range', null, Array ($min_val, $max_val));
			return $res;
		}
		if ( isset($params['max_len'])) {
			$res = $res && mb_strlen($val) <= $params['max_len'];
		}
		if ( isset($params['min_len'])) {
			$res = $res && mb_strlen($val) >= $params['min_len'];
		}
		if (!$res) {
			$error_params = Array (getArrayValue($params, 'min_len'), getArrayValue($params, 'max_len'));
			$this->SetError($field, 'length_out_of_range', null, $error_params);
			return $res;
		}
		return $res;
	}

	/**
	 * Return error message for field
	 *
	 * @param string $field
	 * @return string
	 * @access public
	 */
	function GetErrorMsg($field, $force_escape = null)
	{
		if( !isset($this->FieldErrors[$field]) ) return '';

		$err = getArrayValue($this->FieldErrors[$field], 'pseudo');
		if (!$err) return '';
		// if special error msg defined in config
		if( isset($this->Fields[$field]['error_msgs'][$err]) )
		{
			$msg = $this->Fields[$field]['error_msgs'][$err];
		}
		else //fall back to defaults
		{
			if( !isset($this->ErrorMsgs[$err]) ) {
				trigger_error('No user message is defined for pseudo error <b>'.$err.'</b><br>', E_USER_WARNING);
				return $err; //return the pseudo itself
			}
			$msg = $this->ErrorMsgs[$err];
		}
		$msg = $this->Application->ReplaceLanguageTags($msg, $force_escape);

		if ( isset($this->FieldErrors[$field]['params']) )
		{
			return vsprintf($msg, $this->FieldErrors[$field]['params']);
		}
		return $msg;
	}

	/**
	* Creates a record in the database table with current item' values
	*
	* @param mixed $force_id Set to TRUE to force creating of item's own ID or to value to force creating of passed id. Do not pass 1 for true, pass exactly TRUE!
	* @access public
	* @return bool
	*/
	function Create($force_id = false, $system_create = false)
	{
		if (!$this->raiseEvent('OnBeforeItemCreate')) {
			return false;
		}

		// Validating fields before attempting to create record
		if (!$this->Validate()) {
			return false;
		}

		if (is_int($force_id)) {
			$this->FieldValues[$this->IDField] = $force_id;
		}
		elseif (!$force_id || !is_bool($force_id)) {
			$this->FieldValues[$this->IDField] = $this->generateID();
		}

		$fields_sql = '';
		$values_sql = '';
		foreach ($this->FieldValues as $field_name => $field_value) {
			if ($this->skipField($field_name, $force_id)) {
				continue;
			}

			if (is_null($field_value)) {
				if (array_key_exists('not_null', $this->Fields[$field_name]) && $this->Fields[$field_name]['not_null']) {
					// "kFormatter::Parse" methods converts empty values to NULL and for
	    			// not-null fields they are replaced with default value here
					$values_sql .= $this->Conn->qstr($this->Fields[$field_name]['default']);
				}
				else {
					$values_sql .= $this->Conn->qstr($field_value);
				}
			}
			else {
				if (($field_name == $this->IDField) && ($field_value == 0)) {
					// don't skip IDField in INSERT statement, just use DEFAULT keyword as it's value
					$values_sql .= 'DEFAULT';
				}
				else {
					$values_sql .= $this->Conn->qstr($field_value);
				}
			}

			$fields_sql .= '`' . $field_name . '`, '; //Adding field name to fields block of Insert statement
			$values_sql .= ', ';
		}

		$sql = 'INSERT INTO ' . $this->TableName . ' (' . substr($fields_sql, 0, -2) . ')
				VALUES (' . substr($values_sql, 0, -2) . ')';

		//Executing the query and checking the result
		if ($this->Conn->ChangeQuery($sql) === false) {
			return false;
		}

		$insert_id = $this->Conn->getInsertID();
		if ($insert_id == 0) {
			// insert into temp table (id is not auto-increment field)
			$insert_id = $this->FieldValues[$this->IDField];
		}
		$this->setID($insert_id);

		if (!$system_create){
			$this->setModifiedFlag(clCREATE);
		}

		$this->saveCustomFields();
		if ($this->mode != 't') {
			$this->Application->resetCounters($this->TableName);
		}
		$this->raiseEvent('OnAfterItemCreate');
		$this->Loaded = true;

		return true;
	}

	/**
	* Deletes the record from databse
	*
	* @access public
	* @return bool
	*/
	function Delete($id = null)
	{
		if (isset($id)) {
			$this->setID($id);
		}

		if (!$this->raiseEvent('OnBeforeItemDelete')) {
			return false;
		}

		$sql = 'DELETE FROM ' . $this->TableName . '
				WHERE ' . $this->GetKeyClause('Delete');

		$ret = $this->Conn->ChangeQuery($sql);
		$affected_rows = $this->Conn->getAffectedRows();

		$this->setModifiedFlag(clDELETE); // will change affected rows, so get it before this line

		if ($affected_rows > 0) {
			// something was actually deleted
			$this->raiseEvent('OnAfterItemDelete');
		}

		if ($this->mode != 't') {
			$this->Application->resetCounters($this->TableName);
		}

		return $ret;
	}

	function PopulateMultiLangFields()
	{
		foreach ($this->Fields as $field => $options) {
			// master field is set only for CURRENT language
			$formatter = array_key_exists('formatter', $options) ? $options['formatter'] : false;

			if (($formatter == 'kMultiLanguage') && array_key_exists('master_field', $options) && array_key_exists('error_field', $options)) {
				// MuliLanguage formatter sets error_field to master_field, but in PopulateMlFields mode,
				// we display ML fields directly so we set it back to itself, otherwise error will not be displayed
				unset($this->Fields[$field]['error_field']);
			}
		}
	}

	/**
	 * Sets new name for item in case if it is beeing copied
	 * in same table
	 *
	 * @param array $master Table data from TempHandler
	 * @param int $foreign_key ForeignKey value to filter name check query by
	 * @param string $title_field FieldName to alter, by default - TitleField of the prefix
	 * @param string $format sprintf-style format of renaming pattern, by default Copy %1$s of %2$s which makes it Copy [Number] of Original Name
	 * @access private
	 */
	function NameCopy($master=null, $foreign_key=null, $title_field=null, $format='Copy %1$s of %2$s')
	{
		if (!isset($title_field)) {
		$title_field = $this->Application->getUnitOption($this->Prefix, 'TitleField');
		if (!$title_field || isset($this->CalculatedFields[$title_field]) ) return;
		}

		$new_name = $this->GetDBField($title_field);
		$original_checked = false;
		do {
			if ( preg_match('/'.sprintf($format, '([0-9]*) *', '(.*)').'/', $new_name, $regs) ) {
				$new_name = sprintf($format, ($regs[1]+1), $regs[2]);
			}
			elseif ($original_checked) {
				$new_name = sprintf($format, '', $new_name);
			}

			// if we are cloning in temp table this will look for names in temp table,
			// since object' TableName contains correct TableName (for temp also!)
			// if we are cloning live - look in live
			$query = 'SELECT '.$title_field.' FROM '.$this->TableName.'
								WHERE '.$title_field.' = '.$this->Conn->qstr($new_name);

			$foreign_key_field = getArrayValue($master, 'ForeignKey');
			$foreign_key_field = is_array($foreign_key_field) ? $foreign_key_field[ $master['ParentPrefix'] ] : $foreign_key_field;

			if ($foreign_key_field && isset($foreign_key)) {
				$query .= ' AND '.$foreign_key_field.' = '.$foreign_key;
			}

			$res = $this->Conn->GetOne($query);

			/*// if not found in live table, check in temp table if applicable
			if ($res === false && $object->Special == 'temp') {
				$query = 'SELECT '.$name_field.' FROM '.$this->GetTempName($master['TableName']).'
									WHERE '.$name_field.' = '.$this->Conn->qstr($new_name);
				$res = $this->Conn->GetOne($query);
			}*/

			$original_checked = true;
		} while ($res !== false);
		$this->SetDBField($title_field, $new_name);
	}

	function raiseEvent($name, $id = null, $additional_params = Array())
	{
		if( !isset($id) ) $id = $this->GetID();
		$event = new kEvent( Array('name'=>$name,'prefix'=>$this->Prefix,'special'=>$this->Special) );
		$event->setEventParam('id', $id);

		if ($additional_params) {
			foreach ($additional_params as $ap_name => $ap_value) {
				$event->setEventParam($ap_name, $ap_value);
			}
		}

		$this->Application->HandleEvent($event);
		return $event->status == erSUCCESS ? true : false;
	}

	/**
	 * Set's new ID for item
	 *
	 * @param int $new_id
	 * @access public
	 */
	function setID($new_id)
	{
		$this->ID = $new_id;
		$this->SetDBField($this->IDField, $new_id);
	}

	/**
	 * Generate and set new temporary id
	 *
	 * @access private
	 */
	function setTempID()
	{
		$new_id = (int)$this->Conn->GetOne('SELECT MIN('.$this->IDField.') FROM '.$this->TableName);
		if($new_id > 0) $new_id = 0;
		--$new_id;

		$this->Conn->Query('UPDATE '.$this->TableName.' SET `'.$this->IDField.'` = '.$new_id.' WHERE `'.$this->IDField.'` = '.$this->GetID());

		if ($this->ShouldLogChanges()) {
			// Updating TempId in ChangesLog, if changes are disabled
			$ses_var_name = $this->Application->GetTopmostPrefix($this->Prefix).'_changes_'.$this->Application->GetTopmostWid($this->Prefix);
			$changes = $this->Application->RecallVar($ses_var_name);
			$changes = $changes ? unserialize($changes) : Array ();
			if ($changes) {
				foreach ($changes as $key => $rec) {
					if ($rec['Prefix'] == $this->Prefix && $rec['ItemId'] == $this->GetID()) {
						$changes[$key]['ItemId'] = $new_id;
					}
				}
			}
			$this->Application->StoreVar($ses_var_name, serialize($changes));
		}

		$this->SetID($new_id);
	}

	/**
	 * Set's modification flag for main prefix of current prefix to true
	 *
	 * @access private
	 * @author Alexey
	 */
	function setModifiedFlag($mode = null)
	{
		$main_prefix = $this->Application->GetTopmostPrefix($this->Prefix);
		$this->Application->StoreVar($main_prefix.'_modified', '1', !$this->Application->isAdmin);

		if ($this->ShouldLogChanges()) {
			$this->LogChanges($main_prefix, $mode);
			if (!$this->IsTempTable()) {
				$handler =& $this->Application->recallObject($this->Prefix.'_EventHandler');
				$ses_var_name = $main_prefix.'_changes_'.$this->Application->GetTopmostWid($this->Prefix);
				$handler->SaveLoggedChanges($ses_var_name);
			}
		}
	}

	/**
	 * Determines, that changes made to this item should be written to change log
	 *
	 * @return bool
	 */
	function ShouldLogChanges()
	{
		$log_changes = $this->Application->getUnitOption($this->Prefix, 'LogChanges') || $this->Application->ConfigValue('UseChangeLog');

		return $log_changes && !$this->Application->getUnitOption($this->Prefix, 'ForceDontLogChanges');
	}

	function LogChanges($main_prefix, $mode)
	{
		if (!$mode) {
			return ;
		}

		$ses_var_name = $main_prefix.'_changes_'.$this->Application->GetTopmostWid($this->Prefix);
		$changes = $this->Application->RecallVar($ses_var_name);
		$changes = $changes ? unserialize($changes) : array();

		$general = array(
			'Prefix' => $this->Prefix,
			'ItemId' => $this->GetID(),
			'OccuredOn' => adodb_mktime(),
			'MasterPrefix' => $main_prefix,
			'MasterId' => $this->Prefix == $main_prefix ? $this->GetID() : $this->Application->GetVar($main_prefix.'_id'), // is that correct (Kostja)??
			'Action' => $mode,
		);
		switch ($mode) {
			case clUPDATE:
				$changes[] = array_merge($general, Array(
					'Changes' => serialize(array_merge($this->GetTitleField(), $this->GetChangedFields())),
				));
				break;
			case clCREATE:
				$changes[] = array_merge($general, Array(
					'Changes' => serialize($this->GetTitleField()),
				));
				break;
			case clDELETE:
				$changes[] = array_merge($general, Array(
					'Changes' => serialize(array_merge($this->GetTitleField(), $this->GetRealFields())),
				));
		}

		$this->Application->StoreVar($ses_var_name, serialize($changes));
	}

	function GetTitleField()
	{
		$title_field = $this->Application->getUnitOption($this->Prefix, 'TitleField');
		if ($title_field && $this->GetField($title_field)) {
			return Array($title_field => $this->GetField($title_field));
		}
	}

	function GetRealFields()
	{
		if (function_exists('array_diff_key')) {
			$db_fields = array_diff_key($this->FieldValues, $this->VirtualFields, $this->CalculatedFields);
		}
		else {
			$db_fields = array();
			foreach ($this->FieldValues as $key => $value) {
				if (array_key_exists($key, $this->VirtualFields) || array_key_exists($key, $this->CalculatedFields)) continue;
				$db_fields[$key] = $value;
			}
		}
		return $db_fields;
	}

	function GetChangedFields()
	{
		$changes = array();

		$diff = array_diff_assoc($this->GetRealFields(), $this->OriginalFieldValues);
		foreach ($diff as $field => $new_value) {
			$changes[$field] = array('old' => $this->GetOriginalField($field, true), 'new' => $this->GetField($field));
		}
		return $changes;
	}

	/**
	 * Returns ID of currently processed record
	 *
	 * @return int
	 * @access public
	 */
	function GetID()
	{
		return $this->ID;
	}

	/**
	 * Generates ID for new items before inserting into database
	 *
	 * @return int
	 * @access private
	 */
	function generateID()
	{
		return 0;
	}

	/**
	 * Returns true if item was loaded successfully by Load method
	 *
	 * @return bool
	 */
	function isLoaded()
	{
		return $this->Loaded;
	}

	/**
	 * Checks if field is required
	 *
	 * @param string $field
	 * @return bool
	 */
	function isRequired($field)
	{
		return getArrayValue( $this->Fields[$field], 'required' );
	}

	/**
	 * Sets new required flag to field
	 *
	 * @param string $field
	 * @param bool $is_required
	 */
	function setRequired($field, $is_required = true)
	{
		$this->Fields[$field]['required'] = $is_required;
	}

	function Clear($new_id = null)
	{
		$this->Loaded = false;
		$this->FieldValues = Array();
		$this->OriginalFieldValues = Array ();
		$this->SetDefaultValues(); // will wear off kDBItem::setID effect, so set it later
		$this->FieldErrors = Array();

		$this->setID($new_id);

		return $this->Loaded;
	}

	function Query($force = false)
	{
		if ($this->Application->isDebugMode()) {
			$this->Application->Debugger->appendTrace();
		}

		trigger_error('<b>Query</b> method is called in class <b>'.get_class($this).'</b> for prefix <b>'.$this->getPrefixSpecial().'</b>', E_USER_ERROR);
	}

	function saveCustomFields()
	{
		if (!$this->customFields || $this->inCloning) {
			return true;
		}

		$cdata_key = rtrim($this->Prefix.'-cdata.'.$this->Special, '.');
		$cdata =& $this->Application->recallObject($cdata_key, null, Array('skip_autoload' => true, 'populate_ml_fields' => true));

		$resource_id = $this->GetDBField('ResourceId');
		$cdata->Load($resource_id, 'ResourceId');
		$cdata->SetDBField('ResourceId', $resource_id);

		$ml_formatter =& $this->Application->recallObject('kMultiLanguage');
		/* @var $ml_formatter kMultiLanguage */

		foreach ($this->customFields as $custom_id => $custom_name) {
			$force_primary = isset($cdata->Fields['cust_'.$custom_id]['force_primary']) && $cdata->Fields['cust_'.$custom_id]['force_primary'];
			$cdata->SetDBField($ml_formatter->LangFieldName('cust_'.$custom_id, $force_primary), $this->GetDBField('cust_'.$custom_name));
		}

		if ($cdata->isLoaded()) {
			$ret = $cdata->Update();
		}
		else {
			 $ret = $cdata->Create();
			 if ($cdata->mode == 't') $cdata->setTempID();
		}

		return $ret;
	}

	/**
	 * Returns specified field value from all selected rows.
	 * Don't affect current record index
	 *
	 * @param string $field
	 * @return Array
	 */
	function GetCol($field)
	{
		return Array (0 => $this->GetDBField($field));
	}

}