path: root/services/tagcacheservice.php

<?php

/*
 * This class infers on relation between tags by storing all the including tags or synonymous tag.
 * For example, if the user creates: tag1>tag2>tag3, the system can infer that tag is included into tag1.
 * Instead of computing this relation several times, it is saved into this current table.
 * For synonymy, this table stores also the group of synonymous tags.
 * The table must be updated for each modification of the relations between tags.
 */

class TagCacheService {
	var $db;
	var $tablename;

	function &getInstance(&$db) {
		static $instance;
		if (!isset($instance))
		$instance =& new TagCacheService($db);
		return $instance;
	}

	function TagCacheService(&$db) {
		$this->db =& $db;
		$this->tablename = $GLOBALS['tableprefix'] .'tagscache';
	}

	function getChildren($tag1, $uId) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag1 = $tagservice->normalize($tag1);

		if($tag1 == '') return false;

		$query = "SELECT DISTINCT tag2 as 'tag'";
		$query.= " FROM `". $this->getTableName() ."`";
		$query.= " WHERE relationType = '>'";
		$query.= " AND tag1 = '".$tag1."'";
		$query.= " AND uId = '".$uId."'";

		//die($query);
		if (! ($dbresult =& $this->db->sql_query($query)) ){
			message_die(GENERAL_ERROR, 'Could not get related tags', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}


		$rowset = $this->db->sql_fetchrowset($dbresult);
		$output = array();
		foreach($rowset as $row) {
			$output[] = $row['tag'];
		}

		$this->db->sql_freeresult($dbresult);
		return $output;
	}

	function addChild($tag1, $tag2, $uId) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag1 = $tagservice->normalize($tag1);
		$tag2 = $tagservice->normalize($tag2);

		if($tag1 == $tag2 || strlen($tag1) == 0 || strlen($tag2) == 0
		|| ($this->existsChild($tag1, $tag2, $uId))) {
			return false;
		}

		$values = array('tag1' => $tag1, 'tag2' => $tag2, 'relationType'=> '>', 'uId'=> $uId);
		$query = 'INSERT INTO '. $this->getTableName() .' '. $this->db->sql_build_array('INSERT', $values);
		//die($query);
		if (!($dbresult =& $this->db->sql_query($query))) {
			$this->db->sql_transaction('rollback');
			message_die(GENERAL_ERROR, 'Could not add tag cache inference', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}
		$this->db->sql_transaction('commit');
	}

	function removeChild($tag1, $tag2, $uId) {
		if(($tag1 != '' && $tag1 == $tag2) ||
		($tag1 == '' && $tag2 == '' && $uId == '')) {
			return false;
		}

		$query = 'DELETE FROM '. $this->getTableName();
		$query.= ' WHERE 1=1';
		$query.= strlen($tag1)>0 ? ' AND tag1 = "'. $tag1 .'"' : '';
		$query.= strlen($tag2)>0 ? ' AND tag2 = "'. $tag2 .'"' : '';
		$query.= ' AND relationType = ">"';
		$query.= strlen($uId)>0 ? ' AND uId = "'. $uId .'"' : '';

		if (!($dbresult =& $this->db->sql_query($query))) {
			message_die(GENERAL_ERROR, 'Could not remove tag cache inference', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}
	}
	
	function removeChildren($tag1, $uId) {
		$this->removeChild($tag1, NULL, $uId);
	}

	function existsChild($tag1, $tag2, $uId) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag1 = $tagservice->normalize($tag1);
		$tag2 = $tagservice->normalize($tag2);

		$query = "SELECT tag1, tag2, relationType, uId FROM `". $this->getTableName() ."`";
		$query.= " WHERE tag1 = '" .$tag1 ."'";
		$query.= " AND tag2 = '".$tag2."'";
		$query.= " AND relationType = '>'";
		$query.= " AND uId = '".$uId."'";

		//echo($query."<br>\n");

		return $this->db->sql_numrows($this->db->sql_query($query)) > 0;

	}

	/*
	 * Synonyms of a same concept are a group. A group has one main synonym called key
	 * and a list of synonyms called values.
	 */
	function addSynonym($tag1, $tag2, $uId) {

		if($tag1 == $tag2 || strlen($tag1) == 0 || strlen($tag2) == 0
		|| ($this->existsSynonym($tag1, $tag2, $uId))) {
			return false;
		}

		$case1 = '0'; // not in DB
		if($this->_isSynonymKey($tag1, $uId)) {
			$case1 = 'key';
		} elseif($this->_isSynonymValue($tag1, $uId)) {
			$case1 = 'value';
		}

		$case2 = '0'; // not in DB
		if($this->_isSynonymKey($tag2, $uId)) {
			$case2 = 'key';
		} elseif($this->_isSynonymValue($tag2, $uId)) {
			$case2 = 'value';
		}
		$case = $case1.$case2;

		// all the possible cases
		switch ($case) {
			case 'keykey':
				$values = $this->_getSynonymValues($tag2, $uId);
				$this->removeSynonymGroup($tag2, $uId);
				foreach($values as $value) {
					$this->addSynonym($tag1, $value['tag'], $uId);
				}
				$this->addSynonym($tag1, $tag2, $uId);
				break;

			case 'valuekey':
				$key = $this->_getSynonymKey($tag1, $uId);
				$this->addSynonym($key, $tag2, $uId);
				break;

			case 'keyvalue':
				$this->addSynonym($tag2, $tag1, $uId);
				break;
			case 'valuevalue':
				$key1 =  $this->_getSynonymKey($tag1, $uId);
				$key2 =  $this->_getSynonymKey($tag2, $uId);
				$this->addSynonym($key1, $key2, $uId);
				break;
			case '0value':
				$key = $this->_getSynonymKey($tag2, $uId);
				$this->addSynonym($key, $tag1, $uId);
				break;
			case 'value0':
				$this->addSynonym($tag2, $tag1, $uId);
				break;
			case '0key':
				$this->addSynonym($tag2, $tag1, $uId);
				break;
			default:
				$values = array('tag1' => $tag1, 'tag2' => $tag2, 'relationType'=> '=', 'uId'=> $uId);
				$query = 'INSERT INTO '. $this->getTableName() .' '. $this->db->sql_build_array('INSERT', $values);
				//die($query);
				if (!($dbresult =& $this->db->sql_query($query))) {
					$this->db->sql_transaction('rollback');
					message_die(GENERAL_ERROR, 'Could not add tag cache synonymy', '', __LINE__, __FILE__, $query, $this->db);
					return false;
				}
				$this->db->sql_transaction('commit');
				break;
		}
	}

	function removeSynonymGroup($tag1, $uId) {		
		$query = 'DELETE FROM '. $this->getTableName();
		$query.= ' WHERE 1=1';
		$query.= ' AND tag1 = "'. $tag1 .'"';
		$query.= ' AND relationType = "="';
		$query.= ' AND uId = "'. $uId .'"';

		if (!($dbresult =& $this->db->sql_query($query))) {
			message_die(GENERAL_ERROR, 'Could not remove tag cache inference', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}
	}

	function _isSynonymKey($tag1, $uId) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag1 = $tagservice->normalize($tag1);

		$query = "SELECT tag1 FROM `". $this->getTableName() ."`";
		$query.= " WHERE tag1 = '" .$tag1 ."'";
		$query.= " AND relationType = '='";
		$query.= " AND uId = '".$uId."'";

		return $this->db->sql_numrows($this->db->sql_query($query)) > 0;
	}

	function _isSynonymValue($tag2, $uId) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag2 = $tagservice->normalize($tag2);

		$query = "SELECT tag2 FROM `". $this->getTableName() ."`";
		$query.= " WHERE tag2 = '" .$tag2 ."'";
		$query.= " AND relationType = '='";
		$query.= " AND uId = '".$uId."'";

		return $this->db->sql_numrows($this->db->sql_query($query)) > 0;
	}

	function getSynonyms($tag1, $uId) {	
		$values = array();	
		if($this->_isSynonymKey($tag1, $uId)) {
			$values = $this->_getSynonymValues($tag1, $uId);
		} elseif($this->_isSynonymValue($tag1, $uId)) {
			$key = $this->_getSynonymKey($tag1, $uId);
			$values = $this->_getSynonymValues($key, $uId, $tag1);
			$values[] = $key;			
		}
		return $values;
	}

	function _getSynonymKey($tag2, $uId) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag2 = $tagservice->normalize($tag2);

		if($this->_isSynonymKey($tag2)) return $tag2;
		
		if($tag2 == '') return false;

		$query = "SELECT DISTINCT tag1 as 'tag'";
		$query.= " FROM `". $this->getTableName() ."`";
		$query.= " WHERE relationType = '='";
		$query.= " AND tag2 = '".$tag2."'";
		$query.= " AND uId = '".$uId."'";

		//die($query);
		if (! ($dbresult =& $this->db->sql_query($query)) ){
			message_die(GENERAL_ERROR, 'Could not get related tags', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}

		$row = $this->db->sql_fetchrow($dbresult);
		$this->db->sql_freeresult($dbresult);
		return $row['tag'];
	}

	/*
	 * Return values associated with a key.
	 * $tagExcepted allows to hide a value.
	 */
	function _getSynonymValues($tag1, $uId, $tagExcepted = NULL) {
		$tagservice =& ServiceFactory::getServiceInstance('TagService');
		$tag1 = $tagservice->normalize($tag1);
		$tagExcepted = $tagservice->normalize($tagExcepted);

		if($tag1 == '') return false;

		$query = "SELECT DISTINCT tag2 as 'tag'";
		$query.= " FROM `". $this->getTableName() ."`";
		$query.= " WHERE relationType = '='";
		$query.= " AND tag1 = '".$tag1."'";
		$query.= " AND uId = '".$uId."'";
		$query.= $tagExcepted!=''?" AND tag2!='".$tagExcepted."'":"";

		if (! ($dbresult =& $this->db->sql_query($query)) ){
			message_die(GENERAL_ERROR, 'Could not get related tags', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}

		$rowset = $this->db->sql_fetchrowset($dbresult);

		$output = array();
		foreach($rowset as $row) {
			$output[] = $row['tag'];
		}
		
		$this->db->sql_freeresult($dbresult);
		return $output;
	}

	function existsSynonym($tag1, $tag2, $uId) {
		if($this->_getSynonymKey($tag1, $uId) == $tag2 || $this->_getSynonymKey($tag2, $uId) == $tag1) {
			return true;
		} else {
			return false;
		}
	}


	function updateTag($tag1, $relationType, $otherTags, $uId) {
		if($relationType == '=') {
			if($this->getSynonyms($tag1, $uId)) {  // remove previous data avoiding unconstistency
				$this->removeSynonymGroup($tag1, $uId);
			}
				
			foreach($otherTags as $tag2) {
				$this->addSynonym($tag1, $tag2, $uId);
			}
		} elseif($relationType == '>') {
			if(count($this->getChildren($tag1, $uId))>0) { // remove previous data avoiding unconstistency
				$this->removeChildren($tag1);
			}
			
			foreach($otherTags as $tag2) {
				$this->addChild($tag1, $tag2, $uId);
			}
		}		
	}

	function deleteByUser($uId) {
		$query = 'DELETE FROM '. $this->getTableName() .' WHERE uId = '. intval($uId);

		if (!($dbresult = & $this->db->sql_query($query))) {
			message_die(GENERAL_ERROR, 'Could not delete user tags cache', '', __LINE__, __FILE__, $query, $this->db);
			return false;
		}

		return true;

	}

	function deleteAll() {
		$query = 'TRUNCATE TABLE `'. $this->getTableName() .'`';
		$this->db->sql_query($query);
	}

	// Properties
	function getTableName()       { return $this->tablename; }
	function setTableName($value) { $this->tablename = $value; }
}
?>