* @author  credits to Jason Sweat (added cc, bcc and subject functionality)
 *
 * @param array $params parameters
 *
 * @return string
 */
function smarty_function_mailto($params)
{
    static $_allowed_encoding =
        array('javascript' => true, 'javascript_charcode' => true, 'hex' => true, 'none' => true);
    $extra = '';
    if (empty($params[ 'address' ])) {
        trigger_error("mailto: missing 'address' parameter", E_USER_WARNING);
        return;
    } else {
        $address = $params[ 'address' ];
    }
    $text = $address;
    // netscape and mozilla do not decode %40 (@) in BCC field (bug?)
    // so, don't encode it.
    $search = array('%40', '%2C');
    $replace = array('@', ',');
    $mail_parms = array();
    foreach ($params as $var => $value) {
        switch ($var) {
            case 'cc':
            case 'bcc':
            case 'followupto':
                if (!empty($value)) {
                    $mail_parms[] = $var . '=' . str_replace($search, $replace, rawurlencode($value));
                }
                break;
            case 'subject':
            case 'newsgroups':
                $mail_parms[] = $var . '=' . rawurlencode($value);
                break;
            case 'extra':
            case 'text':
                $$var = $value;
            // no break
            default:
        }
    }
    if ($mail_parms) {
        $address .= '?' . join('&', $mail_parms);
    }
    $encode = (empty($params[ 'encode' ])) ? 'none' : $params[ 'encode' ];
    if (!isset($_allowed_encoding[ $encode ])) {
        trigger_error(
            "mailto: 'encode' parameter must be none, javascript, javascript_charcode or hex",
            E_USER_WARNING
        );
        return;
    }
    // FIXME: (rodneyrehm) document.write() excues me what? 1998 has passed!
    if ($encode === 'javascript') {
        $string = 'document.write(\'' . $text . '\');';
        $js_encode = '';
        for ($x = 0, $_length = strlen($string); $x < $_length; $x++) {
            $js_encode .= '%' . bin2hex($string[ $x ]);
        }
        return '';
    } elseif ($encode === 'javascript_charcode') {
        $string = '' . $text . '';
        for ($x = 0, $y = strlen($string); $x < $y; $x++) {
            $ord[] = ord($string[ $x ]);
        }
        $_ret = "\n";
        return $_ret;
    } elseif ($encode === 'hex') {
        preg_match('!^(.*)(\?.*)$!', $address, $match);
        if (!empty($match[ 2 ])) {
            trigger_error("mailto: hex encoding does not work with extra attributes. Try javascript.", E_USER_WARNING);
            return;
        }
        $address_encode = '';
        for ($x = 0, $_length = strlen($address); $x < $_length; $x++) {
            if (preg_match('!\w!' . Smarty::$_UTF8_MODIFIER, $address[ $x ])) {
                $address_encode .= '%' . bin2hex($address[ $x ]);
            } else {
                $address_encode .= $address[ $x ];
            }
        }
        $text_encode = '';
        for ($x = 0, $_length = strlen($text); $x < $_length; $x++) {
            $text_encode .= '' . bin2hex($text[ $x ]) . ';';
        }
        $mailto = "mailto:";
        return '' . $text_encode . '';
    } else {
        // no encoding
        return '' . $text . '';
    }
}