<?php
/**
 * Akeeba Engine
 * The modular PHP5 site backup engine
 * @copyright Copyright (c)2009-2013 Nicholas K. Dionysopoulos
 * @license GNU GPL version 3 or, at your option, any later version
 * @package akeebaengine
 * @since 3.4
 *
 */

// Protection against direct access
defined('AKEEBAENGINE') or die();

require_once 'interface.php';
require_once 'abstract.php';

class AEPlatform
{
	private $_platformObject = null;
	
	/**
	 * Implements the Singleton pattern for this clas
	 * 
	 * @staticvar AEPlatform $instance The static object instance
	 * @param string $platform Optional; platform name. Autodetect if blank.
	 * @return AEPlatform
	 */
	public static function &getInstance($platform = null)
	{
		static $instance = null;
		
		if(!is_object($instance)) {
			$instance = new AEPlatform($platform);
		}
		
		return $instance;
	}
	
	/**
	 * Public class constructor
	 * @param string $platform Optional; platform name. Leave blank to auto-detect.
	 */
	public function __construct($platform = null)
	{
		if(empty($platform) || is_null($platform)) {
			$platform = $this->detectPlatform();
		}
		
		if(empty($platform)) {
			throw new Exception('Can not find a suitable Akeeba Engine platform for your site');
		}
		
		$this->_platformObject = $this->loadPlatform($platform);
		
		if(!is_object($this->_platformObject)) {
			throw new Exception("Can not load Akeeba Engine platform $platform");
		}
	}
	
	/**
	 * Auto-detect the suitable platform for this site
	 * @return string
	 */
	private function detectPlatform()
	{
		$platforms = $this->listPlatforms();
		
		if(empty($platforms)) throw new Exception('No Akeeba Engine platform class found');
		
		$bestPlatform = (object)array(
			'name'		=> null,
			'priority'	=> 0,
		);
		
		foreach($platforms as $platform) {
			$o = $this->loadPlatform($platform);
			if(is_null($o)) continue;
			
			if($o->isThisPlatform()) {
				if($o->priority > $bestPlatform->priority) {
					$bestPlatform->priority = $o->priority;
					$bestPlatform->name = $platform;
				}
			}
		}
		
		return $bestPlatform->name;
	}
	
	/**
	 * Load a given platform and return the platform object
	 * @param string $platform Platform name
	 * @return AEPlatformAbstract
	 */
	private function &loadPlatform($platform)
	{
		$basedir = dirname(__FILE__);
		$classFile = $basedir.'/'.$platform.'/platform.php';
		$className = 'AEPlatform'.ucfirst($platform);
			
		$null = null;
		if(!file_exists($classFile)) return $null;
		
		require_once($classFile);
		$o = new $className;
		
		return $o;
	}
	
	/**
	 * Lists available platforms
	 * @staticvar array $platforms Static cache of the available platforms
	 * @return array
	 */
	public function listPlatforms()
	{
		static $platforms = array();
		
		if(empty($platforms)) {
			$basedir = dirname(__FILE__);
			$dh = opendir($basedir);
			while($file = readdir($dh)) {
				if(in_array($file,array('.','..'))) continue;
				if(is_dir($basedir.'/'.$file)) {
					$platforms[] = $file;
				}
			}
		}
		
		return $platforms;
	}
	
	/**
	 * Magic method to proxy all calls to the loaded platform object
	 */
	public function __call($name, array $arguments) {
		if(is_null($this->_platformObject)) {
			throw new Exception('Akeeba Engine platform is not loaded');
		}
		
		if(method_exists($this->_platformObject, $name)) {
			// Call_user_func_array is ~3 times slower than direct method calls.
			// (thank you, Nooku Framework, for the tip!)
            switch(count($arguments)) 
            { 
                case 0 :
                    $result = $this->_platformObject->$name();
                    break;
                case 1 : 
                    $result = $this->_platformObject->$name($arguments[0]); 
                    break; 
                case 2: 
                    $result = $this->_platformObject->$name($arguments[0], $arguments[1]); 
                    break; 
                case 3: 
                    $result = $this->_platformObject->$name($arguments[0], $arguments[1], $arguments[2]); 
                    break;
				case 4: 
                    $result = $this->_platformObject->$name($arguments[0], $arguments[1], $arguments[2], $arguments[3]); 
                    break;
				case 5: 
                    $result = $this->_platformObject->$name($arguments[0], $arguments[1], $arguments[2], $arguments[3], $arguments[4]); 
                    break;
                default: 
                    // Resort to using call_user_func_array for many segments 
                    $result = call_user_func_array(array($this->_platformObject, $name), $arguments);
             }
			 return $result;
		} else {
			throw new Exception('Method '.$name.' not found in Akeeba Platform');
		}
	}
	
	public function __get($name) {
		if(isset($this->_platformObject->name) || property_exists($this->_platformObject, $name)) {
			return $this->_platformObject->$name;
		} else {
			$this->_platformObject->$name = null;
			user_error('AEPlatform does not support property '.$name, E_NOTICE);
		}
	}
	
	public function __set($name, $value) {
		if(isset($this->_platformObject->name) || property_exists($this->_platformObject, $name)) {
			$this->_platformObject->$name = $value;
		} else {
			$this->_platformObject->$name = null;
			user_error('AEPlatform does not support property '.$name, E_NOTICE);
		}
	}
}