<?php
/**
 * CUniqueValidator 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/
 */

/**
 * CUniqueValidator validates that the attribute value is unique in the corresponding database table.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CUniqueValidator.php 3260 2011-06-13 20:56:54Z alexander.makarow $
 * @package system.validators
 * @since 1.0
 */
class CUniqueValidator extends CValidator
{
	/**
	 * @var boolean whether the comparison is case sensitive. Defaults to true.
	 * Note, by setting it to false, you are assuming the attribute type is string.
	 */
	public $caseSensitive = true;
	/**
	 * @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;
	/**
	 * @var string the ActiveRecord class name that should be used to
	 * look for the attribute value being validated. Defaults to null, meaning using
	 * the class of the object currently being validated.
	 * You may use path alias to reference a class name here.
	 * @see attributeName
	 * @since 1.0.8
	 */
	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
	 * @since 1.0.8
	 */
	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 string the user-defined error message. The placeholders "{attribute}" and "{value}"
	 * are recognized, which will be replaced with the actual attribute name and value, respectively.
	 */
	public $message;
	/**
	 * @var boolean whether this validation rule should be skipped if when there is already a validation
	 * error for the current attribute. Defaults to true.
	 * @since 1.1.1
	 */
	public $skipOnError = 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)));

		$columnName = $column->rawName;
		$criteria = new CDbCriteria(array(
			'condition' => $this->caseSensitive ? "$columnName=:value" : "LOWER($columnName)=LOWER(:value)",
			'params' => array(':value' => $value),
		));
		if ($this->criteria !== array())
			$criteria->mergeWith($this->criteria);

		if (!$object instanceof CActiveRecord || $object->isNewRecord || $object->tableName() !== $finder->tableName())
			$exists = $finder->exists($criteria);
		else
		{
			$criteria->limit = 2;
			$objects = $finder->findAll($criteria);
			$n = count($objects);
			if ($n === 1)
			{
				if ($column->isPrimaryKey)  // primary key is modified and not unique
					$exists = $object->getOldPrimaryKey() != $object->getPrimaryKey();
				else
				{
					// non-primary key, need to exclude the current record based on PK
					$exists = array_shift($objects)->getPrimaryKey() != $object->getOldPrimaryKey();
				}
			}
			else
				$exists = $n > 1;
		}

		if ($exists)
		{
			$message = $this->message !== null ? $this->message : Yii::t('yii', '{attribute} "{value}" has already been taken.');
			$this->addError($object, $attribute, $message, array('{value}' => $value));
		}
	}
}