<?php
define ('KEYS_CACHE_FILE', '../keyscache.tmp');
/**
 * Class to load sets of objects from XML files into the database
 * XML files can be produced by the 'export' web service or by any other means
 * Here is a simple example:
 * $oLoader  = new XMLDataLoader('../itop-config.php');
 * $oLoader->StartSession();
 * $oLoader->LoadFile('./organizations.xml');
 * $oLoader->LoadFile('./locations.xml');
 * $oLoader->EndSession();
 */
class XMLDataLoader
{
	protected $m_aKeys;
	protected $m_aObjectsCache;
	protected $m_bSessionActive;
	protected $m_oChange;
	protected $m_sCacheFileName;
	
	public function __construct($sConfigFileName)
	{
		$this->m_aKeys = array();
		$this->m_aObjectsCache = array();
		$this->m_oChange = null;
		$this->m_sCacheFileName = dirname(__FILE__).'/'.KEYS_CACHE_FILE;
		$this->InitDataModel($sConfigFileName);
		$this->LoadKeysCache();
		$this->m_bSessionActive = true;

	}
	
	public function StartSession($oChange)
	{
		// Do cleanup any existing cache file (shall not be necessary unless a setup was interrupted abruptely)
		$this->ClearKeysCache();

		$this->m_oChange = $oChange;
		$this->m_bSessionActive  = true;
	}
	
	public function EndSession()
	{
		$this->ResolveExternalKeys();
		$this->m_bSessionActive  = false;
	}
	
	public function __destruct()
	{
		// Stopping in the middle of a session, let's save the context information
		if ($this->m_bSessionActive)
		{
			$this->SaveKeysCache();
		}
		else
		{
			$this->ClearKeysCache();
		}
	}
	
	/**
	 * Initializes the ORM (MetaModel)
	 */	 	
	protected function InitDataModel($sConfigFileName, $bAllowMissingDatabase = true)
	{
		require_once('../core/coreexception.class.inc.php');
		require_once('../core/attributedef.class.inc.php');
		require_once('../core/filterdef.class.inc.php');
		require_once('../core/stimulus.class.inc.php');
		require_once('../core/MyHelpers.class.inc.php');
		require_once('../core/expression.class.inc.php');
		require_once('../core/cmdbsource.class.inc.php');
		require_once('../core/sqlquery.class.inc.php');
		require_once('../core/dbobject.class.php');
		require_once('../core/dbobjectsearch.class.php');
		require_once('../core/dbobjectset.class.php');
		require_once('../core/userrights.class.inc.php');
		MetaModel::Startup($sConfigFileName, $bAllowMissingDatabase);
	}
	
	/**
	 * Stores the keys & object cache in a file
	 */
	protected function SaveKeysCache()
	{
		$hFile = @fopen($this->m_sCacheFileName, 'w');
		if ($hFile !== false)
		{
			$sData = serialize( array('keys' => $this->m_aKeys,
									'objects' => $this->m_aObjectsCache,
									'change' => $this->m_oChange));
			fwrite($hFile, $sData);
			fclose($hFile);
		}
		else
		{
			throw new Exception("Cannot write to file: '{$this->m_sCacheFileName}'");
		}
	}
		 	
	/**
	 * Loads the keys & object cache from the tmp file
	 */
	protected function LoadKeysCache()
	{
		$sFileContent = @file_get_contents($this->m_sCacheFileName);
		if (!empty($sFileContent))
		{
			$aCache = unserialize($sFileContent);
			$this->m_aKeys = $aCache['keys'];
			$this->m_aObjectsCache = $aCache['objects']; 
			$this->m_oChange = $aCache['change']; 
		}
	}	 	
	
	/**
	 * Remove the tmp file used to store the keys cache
	 */
	protected function ClearKeysCache()
	{
		if(is_file($this->m_sCacheFileName))
		{
			unlink($this->m_sCacheFileName);
		}
		else
		{
			//echo "<p>Hm, it looks like the file does not exist!!!</p>";
		}
		$this->m_aKeys = array();
		$this->m_aObjectsCache = array(); 
	}	 	
	
	/**
	 * Helper function to load the objects from a standard XML file into the database
	 */
	function LoadFile($sFilePath)
	{
		global $aKeys;
		
		$oXml = simplexml_load_file($sFilePath);
		
		$aReplicas  = array();
		foreach($oXml as $sClass => $oXmlObj)
		{
			$iSrcId = (integer)$oXmlObj['id']; // Mandatory to cast
			
			// Import algorithm
			// Here enumerate all the attributes of the object
			// for all attribute that is neither an external field
			// not an external key, assign it
			// Store all external keys for further reference
			// Create the object an store the correspondence between its newly created Id
			// and its original Id
			// Once all the objects have been created re-assign all the external keys to
			// their actual Ids
			$oTargetObj = MetaModel::NewObject($sClass);
			foreach(MetaModel::ListAttributeDefs($sClass) as $sAttCode=>$oAttDef)
			{
				if (($oAttDef->IsWritable()) && ($oAttDef->IsScalar()) && ($sAttCode != 'finalclass') )
				{
					if ($oAttDef->IsExternalKey())
					{
						$iDstObj = (integer)($oXmlObj->$sAttCode);
						// Attempt to find the object in the list of loaded objects
						$iExtKey = $this->GetObjectKey($oAttDef->GetTargetClass(), $iDstObj);
						if ($iExtKey == 0)
						{
							$iExtKey = -$iDstObj; // Convention: Unresolved keys are stored as negative !
							$oTargetObj->RegisterAsDirty();
						}
						// tested by Romain, little impact on perf (not significant on the intial setup)
						//$oTargetObj->CheckValue($sAttCode, $iExtKey);
						$oTargetObj->Set($sAttCode, $iExtKey);
					}
					else
					{
						// tested by Romain, little impact on perf (not significant on the intial setup)
						//$oTargetObj->CheckValue($sAttCode, (string)$oXmlObj->$sAttCode);
						$oTargetObj->Set($sAttCode, (string)$oXmlObj->$sAttCode);
					}
				}
			}
			$this->StoreObject($sClass, $oTargetObj, $iSrcId);
		}
		return true;
	}
	
	/**
	 * Get the new ID of an object in the database given its original ID
	 * This may fail (return 0) if the object has not yet been created in the database
	 * This is why the order of the import may be important  
	 */ 
	protected function GetObjectKey($sClass, $iSrcId)
	{
		if (isset($this->m_aKeys[$sClass]) && isset($this->m_aKeys[$sClass][$iSrcId]))
		{
			return $this->m_aKeys[$sClass][$iSrcId];
		}
		return 0;
	}
	
	/**
	 * Store an object in the database and remember the mapping
	 * between its original ID and the newly created ID in the database
	 */  
	protected function StoreObject($sClass, $oTargetObj, $iSrcId)
	{
		try
		{
			if (is_subclass_of($oTargetObj, 'CMDBObject'))
			{
		        $iObjId = $oTargetObj->DBInsertTrackedNoReload($this->m_oChange);
			}
			else
			{
		        $iObjId = $oTargetObj->DBInsertNoReload();
			}
	        
		}
		catch(Exception $e)
		{
			echo $e->GetHtmlDesc();
		}
		$aParentClasses = MetaModel::EnumParentClasses($sClass);
		$aParentClasses[] = $sClass;
		foreach($aParentClasses as $sObjClass)
		{
			$this->m_aKeys[$sObjClass][$iSrcId] = $iObjId;
		}
		$this->m_aObjectsCache[$sClass][$iObjId] = $oTargetObj;
	}
	
	/**
	 * Maps an external key to its (newly created) value
	 */ 
	protected function ResolveExternalKeys()
	{
		foreach($this->m_aObjectsCache as $sClass => $oObjList)
		{
			foreach($oObjList as $oTargetObj)
			{	
				$bChanged = false;
				$sClass = get_class($oTargetObj);
				foreach(MetaModel::ListAttributeDefs($sClass) as $sAttCode=>$oAttDef)
				{
					if ( ($oAttDef->IsExternalKey()) && ($oTargetObj->Get($sAttCode) < 0) ) // Convention unresolved key = negative
					{
						$sTargetClass = $oAttDef->GetTargetClass();
						$iTempKey = $oTargetObj->Get($sAttCode);

						$iExtKey = $this->GetObjectKey($sTargetClass, -$iTempKey);
						if ($iExtKey == 0)
						{
							$sMsg = "unresolved extkey in $sClass::".$oTargetObj->GetKey()."(".$oTargetObj->GetName().")::$sAttCode=$sTargetClass::$iTempKey";
							setup_web_page::log("Warning - $sMsg");
							echo "Warning: $sMsg<br/>\n";
							echo "<pre>aKeys[".$sTargetClass."]:\n";
							print_r($this->m_aKeys[$sTargetClass]);
							echo "</pre>\n";
						}
						else
						{
							$bChanged = true;
							$oTargetObj->Set($sAttCode, $iExtKey);
						}
					}
				}
				if ($bChanged)
				{
					try
					{
						if (is_subclass_of($oTargetObj, 'CMDBObject'))
						{
					        $oTargetObj->DBUpdateTracked($this->m_oChange);
						}
						else
						{
					        $oTargetObj->DBUpdate();
						}
					}
					catch(Exception $e)
					{
						echo $e->GetHtmlDesc();
					}
				}
			}
		}
	
		return true;
	}
}
?>
