<?php
/**
 * TActiveControlAdapter and TCallbackPageStateTracker class file.
 *
 * @author Wei Zhuo <weizhuo[at]gamil[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Web\UI\ActiveControls
 */

namespace Prado\Web\UI\ActiveControls;

/**
 * TCallbackPageStateTracker class.
 *
 * Tracking changes to the page state during callback.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @package Prado\Web\UI\ActiveControls
 * @since 3.1
 */
class TCallbackPageStateTracker
{
	/**
	 * @var TMap new view state data
	 */
	private $_states;
	/**
	 * @var TMap old view state data
	 */
	private $_existingState;
	/**
	 * @var TControl the control tracked
	 */
	private $_control;
	/**
	 * @var object null object.
	 */
	private $_nullObject;

	/**
	 * Constructor. Add a set of default states to track.
	 * @param TControl control to track.
	 */
	public function __construct($control)
	{
		$this->_control = $control;
		$this->_existingState = new TMap;
		$this->_nullObject = new stdClass;
		$this->_states = new TMap;
		$this->addStatesToTrack();
	}

	/**
	 * Add a list of view states to track. Each state is added
	 * to the StatesToTrack property with the view state name as key.
	 * The value should be an array with two enteries. The first entery
	 * is the name of the class that will calculate the state differences.
	 * The second entry is a php function/method callback that handles
	 * the changes in the viewstate.
	 */
	protected function addStatesToTrack()
	{
		$states = $this->getStatesToTrack();
		$states['Visible'] = array('TScalarDiff', array($this, 'updateVisible'));
		$states['Enabled'] = array('TScalarDiff', array($this, 'updateEnabled'));
		$states['Attributes'] = array('TMapCollectionDiff', array($this, 'updateAttributes'));
		$states['Style'] = array('TStyleDiff', array($this, 'updateStyle'));
		$states['TabIndex'] = array('TScalarDiff', array($this, 'updateTabIndex'));
		$states['ToolTip'] = array('TScalarDiff', array($this, 'updateToolTip'));
		$states['AccessKey'] = array('TScalarDiff', array($this, 'updateAccessKey'));
	}

	/**
	 * @return TMap list of viewstates to track.
	 */
	protected function getStatesToTrack()
	{
		return $this->_states;
	}

	/**
	 * Start tracking view state changes. The clone function on objects are called
	 * for those viewstate having an object as value.
	 */
	public function trackChanges()
	{
		foreach($this->_states as $name => $value)
		{
			$obj = $this->_control->getViewState($name);
			$this->_existingState[$name] = is_object($obj) ? clone($obj) : $obj;
		}
	}

	/**
	 * @return array list of viewstate and the changed data.
	 */
	protected function getChanges()
	{
		$changes = array();
		foreach($this->_states as $name => $details)
		{
			$new = $this->_control->getViewState($name);
			$old = $this->_existingState[$name];
			if($new !== $old)
			{
				$diff = new $details[0]($new, $old, $this->_nullObject);
				if(($change = $diff->getDifference()) !== $this->_nullObject)
					$changes[] = array($details[1],array($change));
			}
		}
		return $changes;
	}

	/**
	 * For each of the changes call the corresponding change handlers.
	 */
	public function respondToChanges()
	{
		foreach($this->getChanges() as $change)
			call_user_func_array($change[0], $change[1]);
	}

	/**
	 * @return TCallbackClientScript callback client scripting
	 */
	protected function client()
	{
		return $this->_control->getPage()->getCallbackClient();
	}

	/**
	 * Updates the tooltip.
	 * @param string new tooltip
	 */
	protected function updateToolTip($value)
	{
		$this->client()->setAttribute($this->_control, 'title', $value);
	}

	/**
	 * Updates the tab index.
	 * @param integer tab index
	 */
	protected function updateTabIndex($value)
	{
		$this->client()->setAttribute($this->_control, 'tabindex', $value);
	}

	/**
	 * Updates the modifier access key
	 * @param string access key
	 */
	protected function updateAccessKey($value)
	{
		$this->client()->setAttribute($this->_control, 'accesskey', $value);
	}

	/**
	 * Hides or shows the control on the client-side. The control must be
	 * already rendered on the client-side.
	 * @param boolean true to show the control, false to hide.
	 */
	protected function updateVisible($visible)
	{
		if($visible === false)
			$this->client()->replaceContent($this->_control,"<span id=\"".$this->_control->getClientID()."\" style=\"display:none\" ></span>");
		else
			$this->client()->replaceContent($this->_control,$this->_control);
	}

	/**
	 * Enables or Disables the control on the client-side.
	 * @param boolean true to enable the control, false to disable.
	 */
	protected function updateEnabled($enable)
	{
		$this->client()->setAttribute($this->_control, 'disabled', $enable===false);
	}

	/**
	 * Updates the CSS style on the control on the client-side.
	 * @param array list of new CSS style declarations.
	 */
	protected function updateStyle($style)
	{
		if($style['CssClass']!==null)
			$this->client()->setAttribute($this->_control, 'class', $style['CssClass']);
		if(count($style['Style']) > 0)
			$this->client()->setStyle($this->_control, $style['Style']);
	}

	/**
	 * Updates/adds a list of attributes on the control.
	 * @param array list of attribute name-value pairs.
	 */
	protected function updateAttributes($attributes)
	{
		foreach($attributes as $name => $value)
			$this->client()->setAttribute($this->_control, $name, $value);
	}
}