class AssetDumper

class AssetDumper implements AssetDumperInterface {
    
    /**
     * The path to use for saving the asset.
     *
     * @var string
     */
    protected $path;
    
    /**
     * The extension to use.
     *
     * @var string
     */
    protected $extension;
    
    /**
     * Hash of the AdvAgg settings.
     *
     * @var string
     */
    protected $hash;
    
    /**
     * A config object for the system performance configuration.
     *
     * @var \Drupal\Core\Config\Config
     */
    protected $config;
    
    /**
     * Module handler service.
     *
     * @var \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected $moduleHandler;
    
    /**
     * Construct the AssetDumper instance.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   A config factory for retrieving required config objects.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler.
     */
    public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler) {
        $this->config = $config_factory->get('system.performance');
        $this->hash = '_' . advagg_get_current_hooks_hash() . '.';
        $this->moduleHandler = $module_handler;
    }
    
    /**
     * Set the folder path to save the data to.
     *
     * @param string $file_extension
     *   The extension of the file.
     */
    public function preparePath($file_extension) {
        $this->extension = $file_extension;
        $this->path = 'public://' . $this->extension . '/';
        // Allow other modules to alter the file path.
        // Call hook_advagg_asset_path_alter().
        $this->moduleHandler
            ->alter('advagg_asset_path', $this->path, $this->extension);
        file_prepare_directory($this->path, FILE_CREATE_DIRECTORY);
        return $this->path;
    }
    
    /**
     * {@inheritdoc}
     *
     * The file name for the CSS or JS cache file is generated from the hash of
     * the aggregated contents of the files in $data. This forces proxies and
     * browsers to download new CSS when the CSS changes.
     */
    public function dump($data, $file_extension) {
        if (!isset($this->extension) || $this->extension != $file_extension) {
            $this->preparePath($file_extension);
        }
        // Prefix filename to prevent blocking by firewalls which reject files
        // starting with "ad*".
        $filename = $this->extension . '_' . Crypt::hashBase64($data) . $this->hash . $this->extension;
        $uri = $this->path . $filename;
        // Create the CSS or JS file.
        if (!file_exists($uri) && !file_unmanaged_save_data($data, $uri, FILE_EXISTS_REPLACE)) {
            return FALSE;
        }
        // If CSS/JS gzip compression is enabled and the zlib extension is available
        // then create a gzipped version of this file. This file is served
        // conditionally to browsers that accept gzip using .htaccess rules.
        // It's possible that the rewrite rules in .htaccess aren't working on this
        // server, but there's no harm (other than the time spent generating the
        // file) in generating the file anyway. Sites on servers where rewrite rules
        // aren't working can set css.gzip to FALSE in order to skip
        // generating a file that won't be used.
        if (extension_loaded('zlib') && $this->config
            ->get($file_extension . '.gzip')) {
            if (!file_exists($uri . '.gz') && !file_unmanaged_save_data(gzencode($data, 9, FORCE_GZIP), $uri . '.gz', FILE_EXISTS_REPLACE)) {
                return FALSE;
            }
        }
        return [
            $uri,
            $filename,
        ];
    }

}