langredir.php

<?php

function prefered_language($available_languages, $http_accept_language) {

        $available_languages = array_flip($available_languages);

        $langs = array();
        preg_match_all('~([\w-]+)(?:[^,\d]+([\d.]+))?~', strtolower($http_accept_language), $matches, PREG_SET_ORDER);
        foreach($matches as $match) {

                list($a, $b) = explode('-', $match[1]) + array('', '');
                $value = isset($match[2]) ? (float) $match[2] : 1.0;

                if(isset($available_languages[$match[1]])) {
                        $langs[$match[1]] = $value;
                        continue;
                }

                if(isset($available_languages[$a])) {
                        $langs[$a] = $value - 0.1;
                }

        }
        if($langs) {
                arsort($langs);
                return key($langs);
        }
}


$available_languages = array("cs-cz", "sk-sk", "en-EN", "en", "cs", "sk");

$lang = prefered_language($available_languages, $_SERVER["HTTP_ACCEPT_LANGUAGE"]);

switch($lang) {
    case "sk-sk":
    case "sk":
        header("Location: /sk/", true, 302);
        break;


    case "cs-cz":
    case "cs":
        header("Location: /cs/", true, 302);
        break;


    default:
        header("Location: /en/", true, 302);
        break;
}