<?php

class EngineSystem {
	
	protected static $instances = array();
	
	public static function get ( $name ) {
		
		if ( !empty(static::$instances[$name]) )
			return static::$instances[$name];
		
		throw new Exception(sprintf(
			'EngineSystem "%1$s" not registered !',
			$name
		));
		
	}
	
	public static function set ( $name, $engineClass, $root = '', $cache = '', $mkCache = false ) {
		
		if ( $mkCache && !file_exists($cache) )		
			mkdir($cache, 0777, 1);
		
		return static::$instances[$name] = new static($engineClass, $root, $cache);
		
	}
	
	protected
		$root = '',
		$cache = '',
		$engineClass = '';
	
	protected function __construct ( $engineClass, $root, $cache ) {
		
		if ( !class_exists($engineClass) || !method_exists($engineClass, 'fromFile') )
			throw new Exception(sprintf('Engine class %1$s does not exists or does not have a static "fromFile" method !', $engineClass));
		
		if ( !file_exists($root) )
			throw new Exception(sprintf('Root folder "%1$s" does not exists !', $root));
		
		if ( $cache && !file_exists($cache) )
			throw new Exception(sprintf('Cache folder "%1$s" does not exists !', $cache));
		
		$this->root = realpath($root);
		$this->cache = realpath($cache);
		$this->engineClass = $engineClass;
		
	}
	
	public function load ( $file, $content = null ) {
		
		$engineClass = $this->engineClass;
		
		return $engineClass::fromFile($file, $this->root, $this->cache, $content);
		
	}
	
	public function exists ( $file ) {
		
		$root = Path::get($this->root);
		$file = $root->append($file);
		
		return $file->shift($root) && file_exists($file) && is_file($file);
		
	}
	
	public function getClass () {
		
		return $this->engineClass;
		
	}
	
	public function getRoot () {
		
		return $this->root;
		
	}
	
	public function getCache () {
		
		return $this->cache;
		
	}
	
}

?>