<?php


class Tools
{
    /**
     * get cleaned up var
     * @param string post/get associative array key
     * @return mixed
     */
    public static function getValue($key)
    {
        if(isset($_GET[$key])) {
            $val = $_GET[$key];
        } else if(isset($_POST[$key])) {
            $val = $_POST[$key];
        } else {
            $val = false;
        }

        $val = self::sanitize($val);

        return $val;
    }

    /**
     * clean up field or fiels
     * @param string|array $var
     * @return string|array
     */
    public static function sanitize(&$var)
    {
        if(is_array($var)) {
            foreach($var as &$v) {
                self::sanitize($v);
            }
        } else {
            $var = htmlspecialchars($var);
        }

        return $var;
    }

    /**
     *  Get final redirect url - prepare url for pass GET data,
     *  can be used to make sure about http/https or different languages
     *  without redirects.
     *
     * @param string $url - url to check
     * @return string new final url after all inner redirects
     */
    public static function getRedirectUrl ($url)
    {
        stream_context_set_default(array(
           'http' => array(
               'method' => 'HEAD'
           )
        ));

        $headers = get_headers($url, 1);
        if ($headers !== false && isset($headers['Location'])) {
            return $headers['Location'];
        }

        return false;
    }
}