<?php

	class RelationshipEventHandler extends InpDBEventHandler 
	{
		/**
		 * Add new relation
		 *
		 * @param kEvent $event
		 */
		function OnAddRelation(&$event)
		{
			$this->Application->setUnitOption($event->Prefix,'AutoLoad',false);
			$object =& $event->getObject();
			
			$table_info = $object->getLinkedInfo();
			$main_item_type = $this->Application->getUnitOption($table_info['ParentPrefix'],'ItemType');
			
			$target['id'] = $this->Application->GetVar('TargetId');
			$target['type'] = $this->Application->GetVar('TargetType');
			
			
			$object->SetDBField($table_info['ForeignKey'], $table_info['ParentId']);
			$object->SetDBField('SourceType', $main_item_type);
			$object->SetDBField('TargetId', $target['id']);
			$object->SetDBField('TargetType', $target['type']);
			
			// 1. get item info used in relation
			$configs = $this->extractModulesInfo();
			foreach($configs as $prefix => $config_data)
			{
				if($config_data['ItemType'] == $target['type']) break;
			}
			
			$db =& $this->Application->GetADODBConnection();
			$item['name'] = $db->GetOne('SELECT '.$config_data['TitleField'].' FROM '.$config_data['TableName'].' WHERE ResourceId = '.$target['id']);
			$item['type'] = $this->Application->Phrase($config_data['TitlePhrase']);			
			$object->SetDBField('ItemName', $item['name']);
			$object->SetDBField('ItemType', $item['type']);
			
			$object->setID(0);
			
			$event->redirect = false;
			
			// 2. substitute opener
			$opener_stack = $this->Application->RecallVar('opener_stack');
			$opener_stack = $opener_stack ? unserialize($opener_stack) : Array();
			array_pop($opener_stack);
			
			$new_level = 'index4.php|'.ltrim($this->Application->BuildEnv('in-commerce/products/products_relations',Array('m_opener'=>'u'),'all'),ENV_VAR_NAME.'=');
			array_push($opener_stack,$new_level);
			$this->Application->StoreVar('opener_stack',serialize($opener_stack));
			
			$this->Application->SetVar($event->Prefix_Special.'_SaveEvent','OnCreate');
		}
		
		/**
		 * Creates needed sql query to load list,
		 * if no query is defined in config for
		 * special requested, then use default
		 * query
		 *
		 * @param kEvent $event
		 * @access protected
		 */
		function ListPrepareQuery(&$event)
		{
			return $this->BaseQuery($event,'ListSQLs');
		}
		
		/**
		 * Creates needed sql query to load item,
		 * if no query is defined in config for
		 * special requested, then use default
		 * query
		 *
		 * @param kEvent $event
		 * @access protected
		 */
		function ItemPrepareQuery(&$event)
		{
			return $this->BaseQuery($event,'ItemSQLs');	
		}
		
		
		/**
		 * Get item name & type based on relation type & modules installed
		 *
		 * @param kEvent $event
		 * @param string $sql_field
		 */
		function BaseQuery(&$event, $sql_field)
		{
			$sqls = $this->Application->getUnitOption($event->Prefix,$sql_field);
			$sql = isset($sqls[$event->Special]) ? $sqls[$event->Special] : $sqls[''];
			
			$configs = $this->extractModulesInfo();
			
			// 2. build sql based on information queried
			$sql_templates['ItemName'] = 'IFNULL(%s.%s,\' \')';
			$sql_templates['TableJoin'] = 'LEFT JOIN %1$s ON %1$s.ResourceId = rel.TargetId';
			$sql_templates['TargetName'] = 'IF(rel.TargetType = %s, \'%s\', %s)';

			$sql_parts = Array();
			$sql_parts['TargetName'] = "''";
			foreach($configs as $prefix => $config_data)
			{
				$sql_parts['ItemName'][] = sprintf($sql_templates['ItemName'], $config_data['TableName'], $config_data['TitleField']);
				$sql_parts['TableJoin'][] = sprintf($sql_templates['TableJoin'], $config_data['TableName']);
				
				$sql_parts['TargetName'] = sprintf(	$sql_templates['TargetName'],
					$config_data['ItemType'],
					'!'.$config_data['TitlePhrase'].'!',
					$sql_parts['TargetName']);
				$sql_parts['TargetName'] = str_replace('rel','%1$s',$sql_parts['TargetName']);
			}
			
			$object =& $event->getObject();
					
			$vars = Array('#ITEM_NAMES#', '#ITEM_TYPES#');
			$replacements = Array( implode(', ',$sql_parts['ItemName']), $sql_parts['TargetName'] );
			
			$calculated_fields =& $object->getProperty('CalculatedFields');
			foreach($calculated_fields as $field_name => $field_expression)
			{
				$calculated_fields[$field_name] = str_replace($vars,$replacements,$field_expression);
			}
			
			$object->setProperty('CalculatedFields', $calculated_fields);
					
			$sql = str_replace('#ITEM_JOIN#', implode(' ',$sql_parts['TableJoin']), $sql);
			$sql = str_replace('rel.','%1$s.',$sql);
			
			return $sql;
		}
		
		/**
		 * Get configs from modules installed
		 *
		 * @return Array
		 * @access private
		 */
		function extractModulesInfo()
		{
			// 1. get installed modules & their config info
			$db =& $this->Application->GetADODBConnection();
			$prefixes = $db->GetCol('SELECT Var FROM '.TABLE_PREFIX.'Modules');
			$configs = Array();
			foreach($prefixes as $prefix)
			{
				$configs[$prefix] = $this->Application->getUnitOptions($prefix);
				if($configs[$prefix] === false) unset($configs[$prefix]);
			}
			return $configs;
		}
		
		
		/**
		 * Deletes relations to hooked item from other items
		 *
		 * @param kEvent $event
		 */
		function OnDeleteForeignRelations(&$event)
		{
			$main_object =& $event->MasterEvent->getObject();
			$resource_id = $main_object->GetDBField('ResourceId');
			
			$table = $this->Application->getUnitOption($event->Prefix,'TableName');
			$sql = 'DELETE FROM '.$table.' WHERE TargetId = '.$resource_id;
			$this->Conn->Query($sql);
		}
		
		
	}


?>