<?php
namespace gnomephp;

/**
 *
 * Lightweight spl autoloader for gnomephp namespace and sub namespace.
 * Takes use of GNOME_FW_PATH ( Location is to the root namespace "gnomephp".
 * @author peec
 *
 */
class AutoLoader {

	private $uses = array();

	public function __construct() {
		spl_autoload_register(array($this, 'loader'));


		// Add support for load of new namespaces.
		$uses = Configuration::get('application', 'use');
		if ($uses && is_array($uses) && count($uses) > 0){
			$this->uses = $uses;
		}
	}


	/**
	 * Tries to load a class.
	 * @param string $className
	 * @throws AutoLoaderException
	 */
	private function loader($className) {
			
		// Strip of \ start of ns if any.
		if (substr($className, 0, 1) == '\\')$className = substr($className, 1);
			
		if (substr($className, 0, 8) == 'gnomephp'){
			$clsName = $this->dirify(substr($className, 9, strlen($className)));

			$f = GNOME_FW_PATH.DIRECTORY_SEPARATOR.$clsName.'.php';
			if (file_exists($f))require_once $f;
			else throw new AutoLoaderException("Could not include file $f because it did not exist.");
		}else if (@defined('GNOME_APP_NS') && @defined('GNOME_APP_PATH') && substr($className, 0, strlen(GNOME_APP_NS)) == GNOME_APP_NS){
			$clsName = $this->dirify(substr($className, strlen(GNOME_APP_NS)+1, strlen($className)));
			$f = GNOME_APP_PATH . DIRECTORY_SEPARATOR.$clsName.'.php';
			if (file_exists($f))require_once $f;
			else throw new AutoLoaderException("Could not include file $f because it did not exist.");
		}else{
			foreach($this->uses as $ns => $basePath){
				if (substr($className, 0, strlen($ns)) == $ns){
					// Allow variable.
					$basePath = str_replace('$gnomeAppDir', GNOME_FW_PATH . DIRECTORY_SEPARATOR . '..' . DIRECTORY_SEPARATOR . 'apps', $basePath);
					
					$clsName = $this->dirify(substr($className, strlen($ns)+1, strlen($className)));
					$f = $basePath . DIRECTORY_SEPARATOR . $clsName . '.php';
					if (file_exists($f))require_once $f;
					else throw new AutoLoaderException("Could not include file $f because it did not exist.");
				}
			}
		}
	}

	/**
	 * Converts ns path ( eg. gnomephp\sub\Test )
	 * to
	 * gnomephp (DIRECTORY_SEPARATOR) sub (DIRECTORY_SEPARATOR) Test
	 *
	 * This must be done since linux systems uses another directory separator then windows systems.
	 * @param string $ns A namespace with associated class. eg. gnomephp\sub\Test
	 */
	private function dirify($ns){
		return str_replace('\\', DIRECTORY_SEPARATOR, $ns);
	}


}