<?php
/**
 * CExistValidator class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CExistValidator validates that the attribute value exists in a table.
 *
 * This validator is often used to verify that a foreign key contains a value
 * that can be found in the foreign table.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CExistValidator.php 2799 2011-01-01 19:31:13Z qiang.xue $
 * @package system.validators
 * @since 1.0.4
 */
class CExistValidator extends CValidator
{
	/**
	 * @var string the ActiveRecord class name that should be used to
	 * look for the attribute value being validated. Defaults to null,
	 * meaning using the ActiveRecord class of the attribute being validated.
	 * You may use path alias to reference a class name here.
	 * @see attributeName
	 */
	public $className;
	/**
	 * @var string the ActiveRecord class attribute name that should be
	 * used to look for the attribute value being validated. Defaults to null,
	 * meaning using the name of the attribute being validated.
	 * @see className
	 */
	public $attributeName;
	/**
	 * @var array additional query criteria. This will be combined with the condition
	 * that checks if the attribute value exists in the corresponding table column.
	 * This array will be used to instantiate a {@link CDbCriteria} object.
	 * @since 1.0.8
	 */
	public $criteria = array();
	/**
	 * @var boolean whether the attribute value can be null or empty. Defaults to true,
	 * meaning that if the attribute is empty, it is considered valid.
	 */
	public $allowEmpty = true;

	/**
	 * Validates the attribute of the object.
	 * If there is any error, the error message is added to the object.
	 * @param CModel $object the object being validated
	 * @param string $attribute the attribute being validated
	 */
	protected function validateAttribute($object, $attribute)
	{
		$value = $object->$attribute;
		if ($this->allowEmpty && $this->isEmpty($value))
			return;

		$className = $this->className === null ? get_class($object) : Yii::import($this->className);
		$attributeName = $this->attributeName === null ? $attribute : $this->attributeName;
		$finder = CActiveRecord::model($className);
		$table = $finder->getTableSchema();
		if (($column = $table->getColumn($attributeName)) === null)
			throw new CException(Yii::t('yii', 'Table "{table}" does not have a column named "{column}".',
				array('{column}' => $attributeName, '{table}' => $table->name)));

		$criteria = array('condition' => $column->rawName . '=:vp', 'params' => array(':vp' => $value));
		if ($this->criteria !== array())
		{
			$criteria = new CDbCriteria($criteria);
			$criteria->mergeWith($this->criteria);
		}

		if (!$finder->exists($criteria))
		{
			$message = $this->message !== null ? $this->message : Yii::t('yii', '{attribute} "{value}" is invalid.');
			$this->addError($object, $attribute, $message, array('{value}' => $value));
		}
	}
}