<?php
/**
 * Parameter container
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage base
 */

/**
 * Parameter container
 * 
 * Symply store sort of global parameter
 *
 * @version 0.2.1
 * @package WB
 * @subpackage base
 */
class WBParam
{
   /**
    * actual parameter container
    * 
    * @var array
    */
    static $_param   =   array();
    
   /**
    * parameter listener
    * 
    * @var array
    */
    static $_observer   =   array();
        
   /**
    * static constructor
    * 
    * - remember time of start
    * - load observer class
    */
    static public function staticConstruct()
    {
        // setup system and base dirs
        $sysDir =   realpath(dirname(__FILE__) . '/../..');
        
        self::$_param   =   array(
                'wb'    =>  array(
                    'time'  =>  array(
                        'genesis'   =>  microtime( true )
                    ),
                    'dir'   =>  array(
                        'system'    =>  $sysDir,
                        'base'      =>  $sysDir
                        )
                )
            );
        WBClass::load('WBParam_Observer');
    }
    
   /**
    * receive parameter value
    * 
    * @param string $path parameter path
    * @param mixed $default any default value
    * @return mixed 
    */
    static public function get($path = null, $default = null)
    {
        if (empty($path)) {
            return self::$_param;
        }
        if(!is_array($path)) {
            $path   =   explode('/', $path);
        }
        $path   =   array_map('strtolower', $path);
        
        $config =&  self::$_param;
        foreach ($path as $p) {
            if (!isset($config[$p])) {
                return $default;
            }
            $config     =& $config[$p];
        }
        return $config;
    }

   /**
    * Set parameter value
    * 
    * Inform observer about new value and set parameter to new value
    * 
    * @param string $path parameter path
    * @param mixed $value
    * @return true on success
    */
    static public function set($path = null, $value = null)
    {
        if (empty($path)) {
            self::remove( '' );
            self::$_param   =   $value;
            if (isset(self::$_observer['/'])) {
                foreach (self::$_observer['/'] as $obs) {
                    $obs->notifyOnSet('', $value);
                }
            }
        }
        if (!is_array($path)) {
            $path   =   explode('/', $path);
        }
        $path   =   array_map('strtolower', $path);
        
        $config =&  self::$_param;
        $last   =   array_pop($path);
        foreach ($path as $p) {
            if (!isset($config[$p])) {
                $config[$p] =   array();
            }
            if (!is_array($config[$p])) {
            	WBClass::load('WBException_Config');
            	throw new WBException_Config('Selected path is a leave note, it is not possible to add child nodes', 1, __CLASS__);
            }
            $config     =& $config[$p];
        }

        // remove observer
        $path[] =   $last;
        $path   =   implode('/', $path);
        self::remove($path);
        if (isset(self::$_observer[$path . '/'])) {
            foreach(self::$_observer[$path . '/'] as $obs) {
                $obs->notifyOnSet($path, $value);
            }
        }
        
        // store value
        $config[$last]  =   $value;
        return true;
    }

   /**
    * remove observer when variable was unset
    *
    * This deeply removes all observers along the path
    * 
    * @param string $path parameter path
    * @return bool true on success
    */
    static protected function remove($name)
    {
        // make sure there is a "/" at the end
        $name   =   strtolower(trim($name, '/ ') . '/');
    	
        foreach (array_keys(self::$_observer) as $k) {

            // find matching observer
            $nameLength =   strlen($name);
            if (strncmp($name, $k, $nameLength) != 0 || strlen($k) <= $nameLength) {
                continue;
            }

            // remove them
            foreach (array_keys(self::$_observer[$k]) as $obs) {
                unset(self::$_observer[$k][$obs]);
            }
        }
        return true;
    }    
    
   /**
    * Add observer for parameter
    * 
    * @param string $path parameter path
    * @param WBParam_Observer $obs observer object to be notified
    * @return bool true on success
    */
    static public function attach($name, WBParam_Observer $obs) 
    {
        // make sure there is a "/" at the end
        $name   =   strtolower(trim($name, '/ ') . '/');
        
        if (!isset(self::$_observer[$name])) {
            self::$_observer[$name] =   array();
        }
        
        self::$_observer[$name][$obs->getObjectId()]   =   $obs;
        return true;
    }
    
   /**
    * Remove observer
    * 
    * @param string $path parameter path
    * @param WBParam_Observer $obs observer object to be notified
    * @return bool true on success
    */
    static public function detach($name, WBParam_Observer $obs) 
    {
        // make sure there is a "/" at the end
        $name   =   strtolower(trim($name, '/ ') . '/');
        
        if (!isset(self::$_observer[$name])) {
            return false;
        }
        
        unset(self::$_observer[$name][$obs->getObjectId()]);
        return true;
    }    
}
?>