php file sorter

<?php
    $data = 'V:\\games\\Art';
    $copy = 'V:\\games\\Art_{%}\\Art';
    $index = 0;
    $copied = 0;

    function traverse ($dir) {
        global $data, $copy, $index, $copied;
        $files = scandir($dir);

        foreach ($files as $row) {
            if (in_array($row, ['.', '..'])) {
                continue;
            }

            $file = "{$dir}\\{$row}";

            if (is_dir($file)) {
                traverse ($file);
            } else {
                if ($copied > 1000) {
                    $copied = 0;
                    $index++;
                }

                $_dir = dirname($file);
                $_copy = str_replace('{%}', $index, $copy);

                @mkdir(str_replace($data, $_copy, $_dir), 0777, true);
                copy($file, str_replace($data, $_copy, $file));

                echo "{$file} is copied.\r\n";
                $copied++;
            }
        }
    }

    traverse ($data);
?>