<?php
/**
 * TActiveRecordRelationContext class.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2011 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id$
 * @package System.Data.ActiveRecord.Relations
 */

/**
 * TActiveRecordRelationContext holds information regarding record relationships
 * such as record relation property name, query criteria and foreign object record
 * class names.
 *
 * This class is use internally by passing a context to the TActiveRecordRelation
 * constructor.
 *
 * @author Wei Zhuo <weizho[at]gmail[dot]com>
 * @version $Id$
 * @package System.Data.ActiveRecord.Relations
 * @since 3.1
 */
class TActiveRecordRelationContext
{
	private $_property;
	private $_record;
	private $_relation; //data from an entry of TActiveRecord::$RELATION
	private $_fkeys;

	public function __construct($record, $property=null, $relation=null)
	{
		$this->_record=$record;
		$this->_property=$property;
		$this->_relation=$relation;
	}

	/**
	 * @return boolean true if the relation is defined in TActiveRecord::$RELATIONS
	 * @since 3.1.2
	 */
	public function hasRecordRelation()
	{
		return $this->_relation!==null;
	}

	public function getPropertyValue()
	{
		$obj = $this->getSourceRecord();
		return $obj->getColumnValue($this->getProperty());
	}

	/**
	 * @return string name of the record property that the relationship results will be assigned to.
	 */
	public function getProperty()
	{
		return $this->_property;
	}

	/**
	 * @return TActiveRecord the active record instance that queried for its related records.
	 */
	public function getSourceRecord()
	{
		return $this->_record;
	}

	/**
	 * @return array foreign key of this relations, the keys is dependent on the
	 * relationship type.
	 * @since 3.1.2
	 */
	public function getRelationForeignKeys()
	{
		if($this->_fkeys===null)
			$this->_fkeys=$this->getRelationHandler()->getRelationForeignKeys();
		return $this->_fkeys;
	}

	/**
	 * @return string HAS_MANY, HAS_ONE, or BELONGS_TO
	 */
	public function getRelationType()
	{
		return $this->_relation[0];
	}

	/**
	 * @return string foreign record class name.
	 */
	public function getForeignRecordClass()
	{
		return $this->_relation[1];
	}

	/**
	 * @return string foreign key field names, comma delimited.
	 * @since 3.1.2
	 */
	public function getFkField()
	{
		return $this->_relation[2];
	}

	/**
	 * @return string the query condition for the relation as specified in RELATIONS
	 * @since 3.1.2
	 */
	public function getCondition()
	{
		return isset($this->_relation[3])?$this->_relation[3]:null;
	}

	/**
	 * @return array the query parameters for the relation as specified in RELATIONS
	 * @since 3.1.2
	 */
	public function getParameters()
	{
		return isset($this->_relation[4])?$this->_relation[4]:array();
	}

	/**
	 * @return boolean true if the 3rd element of an TActiveRecord::$RELATION entry is set.
	 * @since 3.1.2
	 */
	public function hasFkField()
	{
		$notManyToMany = $this->getRelationType() !== TActiveRecord::MANY_TO_MANY;
		return $notManyToMany && isset($this->_relation[2]) && !empty($this->_relation[2]);
	}

	/**
	 * @return string the M-N relationship association table name.
	 */
	public function getAssociationTable()
	{
		return $this->_relation[2];
	}

	/**
	 * @return boolean true if the relationship is HAS_MANY and requires an association table.
	 */
	public function hasAssociationTable()
	{
		$isManyToMany = $this->getRelationType() === TActiveRecord::MANY_TO_MANY;
		return $isManyToMany && isset($this->_relation[2]) && !empty($this->_relation[2]);
	}

	/**
	 * @return TActiveRecord corresponding relationship foreign object finder instance.
	 */
	public function getForeignRecordFinder()
	{
		return TActiveRecord::finder($this->getForeignRecordClass());
	}

	/**
	 * Creates and return the TActiveRecordRelation handler for specific relationships.
	 * An instance of TActiveRecordHasOne, TActiveRecordBelongsTo, TActiveRecordHasMany,
	 * or TActiveRecordHasManyAssocation will be returned.
	 * @param TActiveRecordCriteria search criteria
	 * @return TActiveRecordRelation record relationship handler instnace.
	 * @throws TActiveRecordException if property is not defined or missing.
	 */
	public function getRelationHandler($criteria=null)
	{
		if(!$this->hasRecordRelation())
		{
			throw new TActiveRecordException('ar_undefined_relation_prop',
				$this->_property, get_class($this->_record), 'RELATIONS');
		}
		if($criteria===null)
			$criteria = new TActiveRecordCriteria($this->getCondition(), $this->getParameters());
		switch($this->getRelationType())
		{
			case TActiveRecord::HAS_MANY:
				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordHasMany');
				return new TActiveRecordHasMany($this, $criteria);
			case TActiveRecord::MANY_TO_MANY:
				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordHasManyAssociation');
				return new TActiveRecordHasManyAssociation($this, $criteria);
			case TActiveRecord::HAS_ONE:
				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordHasOne');
				return new TActiveRecordHasOne($this, $criteria);
			case TActiveRecord::BELONGS_TO:
				Prado::using('System.Data.ActiveRecord.Relations.TActiveRecordBelongsTo');
				return new TActiveRecordBelongsTo($this, $criteria);
			default:
				throw new TActiveRecordException('ar_invalid_relationship');
		}
	}

	/**
	 * @return TActiveRecordRelationCommand
	 */
	public function updateAssociatedRecords($updateBelongsTo=false)
	{
		$success=true;
		foreach($this->_record->getRecordRelations() as $data)
		{
			list($property, $relation) = $data;
			$belongsTo = $relation[0]==TActiveRecord::BELONGS_TO;
			if(($updateBelongsTo && $belongsTo) || (!$updateBelongsTo && !$belongsTo))
			{
				$obj = $this->getSourceRecord();
				if(!$this->isEmptyFkObject($obj->getColumnValue($property)))
				{
					$context = new TActiveRecordRelationContext($this->getSourceRecord(),$property,$relation);
					$success = $context->getRelationHandler()->updateAssociatedRecords() && $success;
				}
			}
		}
		return $success;
	}

	protected function isEmptyFkObject($obj)
	{
		if(is_object($obj))
			return $obj instanceof TList ? $obj->count() === 0 : false;
		else if(is_array($obj))
			return count($obj)===0;
		else
			return empty($obj);
	}
}