    <?php
require_once 'util/ClassLoader.php';

class Config{

	// Singleton
	private static $instance = null;

	static function getInstance() {
		if ( Config::$instance == null ) {
			Config::$instance = new Config();
		}
		return Config::$instance;
	}
	
	private function __construct() {
		$this->configuration = array();
	}
	
	// members
	private $configuration;
	
    public static function setConfiguration($configurationArray) {
    	$conf = self::getInstance();
 		$conf->configuration = array_merge ($conf->configuration, $configurationArray);
    	if ($autoloader = $conf->getConfig("autoloader")) {
    		spl_autoload_register($autoloader);
    	}
    }

    function getConfig($key, $default = null){
      if (array_key_exists($key, $this->configuration))
    		return $this->configuration[$key];
    	else {
    		if ($default)
    			return $default;
    	}
    	return null;
    }

	function requireConfig($key){
		if (($value = $this->getConfig($key)) == null)
			throw new Exception("Configuration for $key missing");
		return $value;
	}
	
	// sets path of calling module as app_path
	static function setAppPath() {
	    $call_stack = debug_backtrace();
	    $file = $call_stack[0]['file'];
        $path = substr($file, 0, strrpos($file, "/"));
        $path = substr($file, 0, strrpos($path, "/"));
        self::getInstance()->configuration["app_path"] = $path;
	}
}

?>