class CssOptimizer

class CssOptimizer extends AssetOptimizer {
    
    /**
     * {@inheritdoc}
     */
    public function __construct(ConfigFactoryInterface $config_factory, ContainerAwareEventDispatcher $event_dispatcher, CacheBackendInterface $cache) {
        $this->extension = 'css';
        parent::__construct($config_factory, $event_dispatcher, $cache);
    }
    
    /**
     * {@inheritdoc}
     */
    protected function addDnsPrefetch(array $asset) {
        $prefetch = [];
        if (!isset($asset['contents'])) {
            return $prefetch;
        }
        $matches = [];
        $pattern = '%url\\(\\s*+[\'"]?+(http:\\/\\/|https:\\/\\/|\\/\\/)([^\'"()\\s]++)[\'"]?+\\s*+\\)%i';
        preg_match_all($pattern, $asset['contents'], $matches);
        if (!empty($matches[1])) {
            foreach ($matches[1] as $key => $match) {
                $parse = @parse_url($match . $matches[2][$key]);
                if (!empty($parse['host'])) {
                    $prefetch[] = $parse['host'];
                }
            }
        }
        return $prefetch;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function fixType(array &$asset) {
        // Default asset type to file if not set/invalid.
        if (!in_array($asset['type'], [
            'file',
            'external',
            'settings',
        ])) {
            $asset['type'] = 'file';
        }
        $path = $asset['data'];
        if ($asset['type'] === 'external') {
            // If type is external but path doesn't start with http, https, or //
            // change it to file.
            if (stripos($path, 'http') !== 0 && stripos($path, '//') !== 0) {
                $asset['type'] = 'file';
            }
            elseif (stripos($path, $this->basePath) !== FALSE && !$this->config
                ->get('css.preserve_external')) {
                $asset['type'] = 'file';
                $asset['group'] = CSS_BASE;
                $asset['every_page'] = TRUE;
                $asset['weight'] = -40000;
                $asset['data'] = substr($asset['data'], stripos($asset['data'], $this->basePath) + $this->basePathLen);
            }
        }
        elseif ($asset['type'] === 'file' && (stripos($path, 'http') === 0 || stripos($path, '//') === 0)) {
            $asset['type'] = 'external';
        }
    }
    
    /**
     * {@inheritdoc}
     */
    protected function optimizeFile(array &$asset, array $data) {
        $contents = $this->updateUrls($data['contents'], $asset['data']);
        if ($this->config
            ->get('css.combine_media') && $asset['media'] !== 'all') {
            $contents = "@media {$asset['media']}{{$contents}}";
            $asset['media'] = 'all';
        }
        $asset_event = new AssetOptimizationEvent($contents, $asset, $data);
        $this->eventDispatcher
            ->dispatch(AssetOptimizationEvent::CSS, $asset_event);
        $contents = $asset_event->getContent();
        $asset = $asset_event->getAsset();
        // If file contents are unaltered return FALSE.
        if ($contents === $data['contents'] && !$this->gZip) {
            return FALSE;
        }
        return $this->writeFile($contents, $data['cid']);
    }
    
    /**
     * Update any internal urls.
     *
     * @param string $contents
     *   The file contents.
     * @param string $path
     *   The file path.
     *
     * @return string
     *   The updated contents.
     */
    public function updateUrls($contents, $path) {
        // Determine the file's directory including the Drupal base path.
        $directory = base_path() . dirname($path) . '/';
        // Alter all internal url() paths. Leave external paths alone. We don't need
        // to normalize absolute paths here because that will be done later. Also
        // ignore SVG paths (# or %23). Expected form: url("/images/file.jpg") which
        // gets converted to url("${directory}/images/file.jpg").
        return preg_replace('/url\\(\\s*([\'"]?)(?![a-z]+:|\\/+|\\#|\\%23+)([^\'")]+)([\'"]?)\\s*\\)/i', 'url(\\1' . $directory . '\\2\\3)', $contents);
    }

}