Php multlang support

index.php

<?php 

include_once ('Lang.class.php');
$lang = new Lang(Lang::detect());
//$lang = new Lang('uk');

echo $lang->get('main_title');

Lang.class.php

<?php

/**
 * Класс работы с мультиязычностью.
 *
 * @author aNNiMON, web_demon
 */
final class Lang {
    
    const PATH = 'lang/';
    const EXT = '.ini';
    const DEFAULT_LANGCODE = 'en';
    
    public static function detect() {
        $lang = (!empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) ? $_SERVER['HTTP_ACCEPT_LANGUAGE'] : '';
        $lang = (!empty($lang)) ? explode(';', $lang) : $lang;
        $lang = (!empty($lang['0'])) ? explode(',', $lang['0']) : $lang;
        $lang = (!empty($lang['0'])) ? explode('-', $lang['0']) : $lang;
        return $lang['0']; 
    }
    
    private $lang = '';
    private $keys;

    public function __construct($lang) {
        $this->set($lang);
    }
    
    public function set($lang) {
        $this->load($lang);
    }
    
    /**
     * Получить текст перевода по ключу
     * @param type $key
     * @return type
     */
    public function get($key) {
        if (empty($this->keys[$key])) {
            return $key;
        }
        return $this->keys[$key];
    }
    
    public function getLangCode() {
        return $this->lang;
    }

    private function load($lang) {
        if ($this->isExists($lang)) $this->lang = $lang;
        else $this->lang = self::DEFAULT_LANGCODE;
        
        $ini_file = self::PATH . $this->lang . self::EXT;
        $this->keys = parse_ini_file($ini_file);
    }
    
    private function isExists($lang) {
        $ini_file = self::PATH . $lang . self::EXT;
        return file_exists($ini_file);
    }
}