<?php

define('AJAX_LOCKING_LOCKED', 'locked');
define('AJAX_LOCKING_UNLOCKED', 'unlocked');
define('AJAX_LOCKING_OWNED', 'owned');
define('AJAX_LOCKING_TIMEOUT', 'timeout');

define('AJAX_LOCKING_PREFIX', 'ajaxlock');

/**
 * This class implements a base class for AJAX_Locking drivers.
 */
class AJAX_Locking_Driver
{
	var $timeout = 3600;

	/**
	 * Constructor
	 *
	 * @return AJAX_Locking_Driver
	 */
	function AJAX_Locking_Driver($timeout = 3600)
	{
		if ($timeout) $this->timeout = $timeout;
	}

	/**
	 * Locks an object
	 *
	 * @param mixed $user	id of the user who wants to lock
	 * @param string $type	type/classname of the object
	 * @param mixed $id		id of the object
	 * @return boolean true if the lock was successfull or the user is the owner
	 *                      false otherwise
	 */
	function lock($user, $type, $id)
	{
		return true;
	}

	/**
	 * Unlocks an object
	 *
	 * @param mixed $user	id of the user who wants to unlock
	 * @param string $type	type/classname of the object
	 * @param mixed $id		id of the object
	 * @return boolean true if the unlock was successfull, false otherwise
	 */
	function unlock($user, $type, $id)
	{
		return true;
	}

	/**
	 * Returns the status of the object (lock or unlocked)
	 *
	 * @param mixed $user	id of the user who wants to know the object's status
	 * @param string $type	type/classname of the object
	 * @param mixed $id		id of the object
	 * @return string the status and the owner of the object
	 */
	function status($user, $type, $id)
	{
		return AJAX_LOCKING_UNLOCKED . "~";
	}

	/**
	 * Returns the list of all active locks for administration purpose
	 *
	 * @return array of locks (owner, type, id), false if not implemented
	 */
	function getLocks()
	{
	    return false;
	}

	/**
	 * Administrately delete a lock
	 *
	 * @param string $type
	 * @param mixed $id
	 *
	 * @return true if the lock is deleted successfully, false otherwise
	 */
    function deleteLock($type, $id)
    {
        return false;
    }

	function _getKey($type, $id)
	{
		return AJAX_LOCKING_PREFIX . '.' . $type . '.' . $id;
	}

	function _getValue($user, $type, $id)
	{
		return implode('~', array($user, $type, $id, time()));
	}

	function _parseValue($value)
	{
		return explode('~', $value);
	}
}
?>