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

WBClass::load('WBCache');

/**
 * Instance creator
 *
 * Load XML config files
 *
 * @version 0.5.0
 * @package WB
 * @subpackage base
 */
class WBConfig extends WBStdClass
{
    /**
     * previously loaded config
     * @var  array
     */
    private static $_configBuffer   = array();

    /**
     * currently loaded configuration values
     * @var  array
     */
    private $_current   = array();
    
    /**
     * XML config string
     * @var WBConfig_Loader
     */
    private $loader;

    /**
     * constructor
     * 
     * start patI18n
     */
    public function __construct()
    {
        WBClass::create('patI18n');
        $this->setLoader();
    }
    
    /**
     * Choose loader
     * 
     * Tell config class how to load XML-strings of config
     * 
     * @param string $loader
     */
    public function setLoader($loader = 'File')
    {
        $this->loader   =   WBClass::create('WBConfig_Loader_'. $loader);
    }
    
    /**
     * Receive current config loader object
     * 
     * @return WBConfig_Loader
     */
    public function getLoader()
    {
        return $this->loader;
    }
    
   /**
    * receive config value by path
    *
    *  
    *
    * @param string|array $path sort of x-path expression
    * @param mixed $default value to return if not found
    * @return string|array configuration value of selected path or "null" if not found
    */
    public function get( $path = null, $default = null )
    {
        if( empty( $path ) ) {
            return $this->_current;
        }

        if( !is_array( $path ) ) {
            $path   =   explode( '/', $path );
        }

        // walk through path
        $config =&  $this->_current;
        foreach( $path as $p ) {
            if (!isset($config[$p]) || !is_array($config)) {
                return $default;
            }
            $config     =& $config[$p];
        }
        return $config;
    }

   /**
    * load configuration
    *
    * Well, load it from file or cache or buffer
    *
    * @param string $file
    * @param bool $try try to load, don't throw an exception
    * @return bool true on success
    * @throws WBException_File
    */
    public function load($file, $try = false)
    {
        // loaded before?
        $lang   =   patI18n::getLocale();
        if (isset(self::$_configBuffer[$lang . '-' . $file])) {
            $this->_current = self::$_configBuffer[$lang . '-' . $file];
            return true;
        }
        
        // shortcut using cache
        $cache    =    WBCache::get($lang . '/' .  $file);
        if ($cache) {
            $this->_current =   $cache;
            return true;
        }
        
        $expire =   array();
        if (!$this->loader->load($file, $data, $expire, $try)) {
            return false;
        }
        
        $this->_current =   array();
        if (empty($data)) {
            return false;
        }
        
        $unser          =   WBClass::create('WBConfig_Unserializer');
        $unser->setLoader($this->loader->getName());
        $this->_current =   $unser->unserialize($data);
        if (empty($this->_current)) {
            return false;
        }
        
        self::$_configBuffer[$lang . '-' . $file] =   $this->_current;
        WBCache::set($lang . '/' . $file,  $this->_current, $expire);
        return true;
    }
    
    /**
     * Check if Configuration Exists
     * 
     * In case current config is empty, return false
     *
     * @return bool
     */
    public function has()
    {
        if (empty($this->_current)) {
            return false;
        }
        return true;
    }
        
    /**
     * force reload of config file
     * 
     * Empty local config buffer and load config normally. This allows to 
     * reload a configuration file within the same process
     * 
     * @uses load() 
     * @param string $file
     * @param bool $try try to load, don't throw an exception
     * @return bool true on success
     */
    public function reload($file, $try = false)
    {
        // loaded before?
        if (isset(self::$_configBuffer[$file])) {
            unset(self::$_configBuffer[$file]);
        }
        
        clearstatcache();
        return $this->load($file, $try);
    }
}