<?php
/*************************************************************************************************
 * LiveCart																					  *
 * Copyright (C) 2007-2009 UAB "Integry Systems" (http://livecart.com)							*
 * All rights reserved																		   *
 *																							   *
 * This source file is a part of LiveCart software package and is protected by LiveCart license. *
 * The license text can be found in the license.txt file. In case you received a package without *
 * a license file, the license text is also available online at http://livecart.com/license	  *
 *************************************************************************************************/

include_once(dirname(__file__) . '/schema/ARField.php');
include_once(dirname(__file__) . '/ARSerializableDateTime.php');

/**
 * Binds a value to a schema field
 * (it is just an ordinary row field value container)
 *
 * @package activerecord
 * @author Integry Systems
 */
class ARValueMapper implements Serializable
{
	/**
	 * Schema field instance
	 *
	 * @var ARSchemaField
	 */
	private $field = null;

	/**
	 * Value assigned to a schema field
	 *
	 * @var mixed
	 */
	private $value = null;

	/**
	 * Initial ID value (reset after saving)
	 *
	 * Necessary when a record primary key values change and record needs to be updated (referencing the old ID values)
	 *
	 * @var mixed
	 */
	private $initialID = null;

	/**
	 * Initial value (reset after saving)
	 *
	 * Necessary to know when value changes change (other) objects state
	 *
	 * For example, changing products stock count from 0 to 5 would increase the count of the available
	 * products by 1, but changing the stock count from 5 to 10 wouldn't affect affect this count, so it's
	 * sometimes not enough just to be able to check that the value has been changed.
	 *
	 * @var mixed
	 */
	private $initialValue = null;

	/**
	 * A mark to indicate if a record was modified
	 *
	 * @var bool
	 */
	private $isModified = false;

	private $isNull = false;

	public function __construct(ARField $field, $value = null)
	{
		$this->field = $field;
		$this->value = $value;

		if (($this->field->getDataType() instanceof ARDateTime) && !($value instanceof ARSerializableDateTime))
		{
			$this->value = new ARSerializableDateTime($this->value);
		}

		$this->initialValue = $value;
	}

	/**
	 * Gets a related schema field
	 *
	 * @return ARField
	 */
	public function getField()
	{
		return $this->field;
	}

	/**
	 * Sets a related schema field.
	 *
	 * This method should never be called directly
	 *
	 * @return ARField
	 */
	public function setField(ARField $field)
	{
		$this->field = $field;
	}

	/**
	 * Assigns a value to a field
	 *
	 * @param mixed $value
	 */
	public function set($value = null, $markAsModified = true)
	{
		if (is_null($value))
		{
			$this->setNull();
			return false;
		}

		// === also checks variable type, so we use == to compare values
		if (!is_null($this->initialValue) && (!is_object($this->value) && !is_object($value) && ($value == $this->value)) )
		{
			return false;
		}

		if ($this->field instanceof ARForeignKey)
		{
			if (!($value instanceof ActiveRecord))
			{
				throw new ARException("Invalid value parameter: must be an instance of ActiveRecord");
			}
			else if (!is_a($value, $this->field->getForeignClassName()))
			{
				throw new ARException("Invalid value parameter: must be an instance of " . $this->field->getForeignClassName());
			}
			else if ($this->value && ($this->value === $value))
			{
				return false;
			}

			if ($this->value && !$this->initialID)
			{
				$this->initialID = $value->getID();
			}
		}
		else if ($this->field)
		{
			$value = $this->field->getDataType()->getValidatedValue($value);
		}

		$this->isNull = false;
		$this->value = $value;

		if ($markAsModified)
		{
			$this->isModified = true;
		}
	}

	public function setNull($markAsModified = true)
	{
		$this->value = null;
		$this->isNull = true;
		if ($markAsModified)
		{
			$this->isModified = true;
		}
	}

	public function isNull()
	{
		return $this->isNull;
	}

	/**
	 * Gets a field value
	 *
	 * @return mixed
	 */
	public function get()
	{
		return $this->value;
	}

	/**
	 * Gets initial field ID value
	 *
	 * @return mixed
	 */
	public function getInitialID()
	{
		if (!$this->initialID)
		{
			return $this->value->getID();
		}
		else
		{
			return $this->initialID;
		}
	}

	/**
	 * Gets initial field value
	 *
	 * @return mixed
	 */
	public function getInitialValue()
	{
		return $this->initialValue;
	}

	/**
	 * Returns true if field is being modified
	 *
	 * @return bool
	 */
	public function isModified()
	{
		return $this->isModified;
	}

	/**
	 * Marks field as modified
	 */
	public function setAsModified()
	{
		$this->isModified = true;
	}

	/**
	 * Marks the field as not modified (after saving, etc.)
	 */
	public function resetModifiedStatus($isModified = false)
	{
		$this->isModified = $isModified;

		if (!$isModified && $this->field instanceof ARForeignKey && !is_null($this->value))
		{
			$this->initialID = $this->value->getID();
		}

		if (!$isModified)
		{
			$this->initialValue = $this->value;
		}
	}

	/**
	 * Checks if this instance has an assigned value
	 *
	 * @return bool
	 */
	public function hasValue()
	{
		if ($this->value != null)
		{
			return true;
		}
		else
		{
			return false;
		}
	}

	public function serialize()
	{
		return serialize($this->value);
	}

	public function unserialize($serialized)
	{
		$this->set(unserialize($serialized), false);
	}

	public function destructValue()
	{
		$this->initialValue = null;

		if ($this->value instanceof ActiveRecord && !$this->value->isDestructing())
		{
			$this->value->__destruct();
		}

		$this->value = null;
	}

	public function __clone()
	{
		$this->isModified = true;
		$this->initialID = null;
		$this->initialValue = null;

		if ($this->field instanceof ARPrimaryKeyField)
		{
			$this->setNull(true);
			$this->value = null;
		}
	}
}

?>