public function toCss($path)
    {
        $filePath = $this->destPath.'/'.$path;
        $subPath = substr($path, 0, strrpos($path, '/'));

        if (is_file($filePath)) {
            $extension = (new \SplFileInfo($filePath))->getExtension();
            switch ($extension) {
                case 'scss':
                    $scssPhp = new Compiler();
                    $scssPhp->setImportPaths($this->destPath.'/'.$subPath);
                    $targetPath = preg_replace('/scss/m', 'css', $path);

                    // compile if target file doesn't exists
                    if (!$this->fileSystem->exists($this->destPath.'/'.$targetPath)) {
                        $scss = file_get_contents($filePath);
                        $css = $scssPhp->compile($scss);
                        $this->fileSystem->dumpFile($this->destPath.'/'.$targetPath, $css);
                    }

                    return $targetPath;
                    break;
                default:
                    throw new Exception(sprintf("File '%s' should be a '.scss'!", $path));
            }
        }

        throw new Exception(sprintf("File '%s' doesn't exist!", $path));
    }