<?php

/**

 * @version 	$Id$

 * @category	Koowa

 * @package		Koowa_Database

 * @subpackage 	Behavior

 * @copyright	Copyright (C) 2007 - 2010 Johan Janssens. All rights reserved.

 * @license		GNU GPLv3 <http://www.gnu.org/licenses/gpl.html>

 */



/**

 * Database Lockable Behavior

 *

 * @author		Johan Janssens <johan@nooku.org>

 * @category	Koowa

 * @package     Koowa_Database

 * @subpackage 	Behavior

 */

class KDatabaseBehaviorLockable extends KDatabaseBehaviorAbstract

{

	/**

	 * The lock lifetime

	 *

	 * @var integer

	 */

	protected $_lifetime;

	

	/**

     * Initializes the options for the object

     *

     * Called from {@link __construct()} as a first step of object instantiation.

     *

     * @param 	object 	An optional KConfig object with configuration options

     * @return void

     */

	protected function _initialize(KConfig $config)

    {

    	$config->append(array(

			'priority'   => KCommand::PRIORITY_HIGH,

    	    'lifetime'	 => '900' //in seconds

	  	));

	  	

	  	$this->_lifetime = $config->lifetime;

	  		

    	parent::_initialize($config);

   	}

	

	/**

	 * Get the methods that are available for mixin based

	 *

	 * This function conditionaly mixies the behavior. Only if the mixer

	 * has a 'locked_by' property the behavior will be mixed in.

	 *

	 * @param object The mixer requesting the mixable methods.

	 * @return array An array of methods

	 */

	public function getMixableMethods(KObject $mixer = null)

	{

		$methods = array();



		if(isset($mixer->locked_by) && isset($mixer->locked_on)) {

			$methods = parent::getMixableMethods($mixer);

		}



		return $methods;

	}



	/**

	 * Lock a row

	 *

	 * Requires an 'locked_on' and 'locked_by' column

	 *

	 * @return boolean	If successfull return TRUE, otherwise FALSE

	 */

	public function lock()

	{

		//Prevent lock take over, only an saved and unlocked row and be locked

		if(!$this->isNew() && !$this->locked())

		{

			$this->locked_by = (int) JFactory::getUser()->get('id');

			$this->locked_on = gmdate('Y-m-d H:i:s');

			$this->save();

		}



		return true;

	}



	/**

	 * Unlock a row

	 *

	 * Requires an locked_on and locked_by column to be present in the table

	 *

	 * @return boolean	If successfull return TRUE, otherwise FALSE

	 */

	public function unlock()

	{

		$userid = JFactory::getUser()->get('id');



		//Only an saved row can be unlocked by the user who locked it

		if(!$this->isNew() && $this->locked_by != 0 && $this->locked_by == $userid)

		{

			$this->locked_by = 0;

			$this->locked_on = 0;



			$this->save();

		}



		return true;

	}



	/**

	 * Checks if a row is locked

	 *

	 * @return boolean	If the row is locked TRUE, otherwise FALSE

	 */

	public function locked()

	{

		$result = false;

		if(!$this->isNew())

		{

		    if(isset($this->locked_on) && isset($this->locked_by)) 

			{    

			    $locked  = strtotime($this->locked_on);

                $current = strtotime(gmdate('Y-m-d H:i:s'));

                                    

                //Check if the lock has gone stale

                if($current - $locked < $this->_lifetime) 

			    {

                    $userid = JFactory::getUser()->get('id');

			        if($this->locked_by != 0 && $this->locked_by != $userid) {

			            $result= true;

                    }

			    }

			}

		}

		

		return $result;

	}



	/**

	 * Get the locked information

	 *

	 * @return string	The locked information as an internationalised string

	 */

	public function lockMessage()

	{

		$message = '';



		if($this->locked())

		{

	        $user = JFactory::getUser($this->locked_by);	    

			$date = $this->getService('com:default.template.helper.date')->humanize(array('date' => $this->locked_on));



			$message = JText::sprintf('Locked by %s %s', $user->get('name'), $date);

		}



		return $message;

	}



	/**

	 * Checks if a row can be updated

	 *

	 * This function determines if a row can be updated based on it's locked_by information.

	 * If a row is locked, and not by the logged in user, the function will return false,

	 * otherwise it will return true

	 *

	 * @return boolean True if row can be updated, false otherwise

	 */

	protected function _beforeTableUpdate(KCommandContext $context)

	{

		return (bool) !$this->locked();

	}

	

	/**

	 * Checks if a row can be deleted

	 *

	 * This function determines if a row can be deleted based on it's locked_by information.

	 * If a row is locked, and not by the logged in user, the function will return false,

	 * otherwise it will return true

	 * 	

	 * @return boolean True if row can be deleted, false otherwise

	 */

	protected function _beforeTableDelete(KCommandContext $context)

	{

		return (bool) !$this->locked();

	}

}