class ConfigController

class ConfigController implements ContainerInjectionInterface {
  use StringTranslationTrait;

  /**
   * The target storage.
   *
   * @var \Drupal\Core\Config\StorageInterface
   */
  protected $targetStorage;

  /**
   * The sync storage.
   *
   * @var \Drupal\Core\Config\StorageInterface
   */
  protected $syncStorage;

  /**
   * The import transformer service.
   *
   * @var \Drupal\Core\Config\ImportStorageTransformer
   */
  protected $importTransformer;

  /**
   * The configuration manager.
   *
   * @var \Drupal\Core\Config\ConfigManagerInterface
   */
  protected $configManager;

  /**
   * The export storage.
   *
   * @var \Drupal\Core\Config\StorageInterface
   */
  protected $exportStorage;

  /**
   * The file download controller.
   *
   * @var \Drupal\system\FileDownloadController
   */
  protected $fileDownloadController;

  /**
   * The diff formatter.
   *
   * @var \Drupal\Core\Diff\DiffFormatter
   */
  protected $diffFormatter;

  /**
   * The file system.
   *
   * @var \Drupal\Core\File\FileSystemInterface
   */
  protected $fileSystem;

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container
      ->get('config.storage'), $container
      ->get('config.storage.sync'), $container
      ->get('config.manager'), FileDownloadController::create($container), $container
      ->get('diff.formatter'), $container
      ->get('file_system'), $container
      ->get('config.storage.export'), $container
      ->get('config.import_transformer'));
  }

  /**
   * Constructs a ConfigController object.
   *
   * @param \Drupal\Core\Config\StorageInterface $target_storage
   *   The target storage.
   * @param \Drupal\Core\Config\StorageInterface $sync_storage
   *   The sync storage.
   * @param \Drupal\Core\Config\ConfigManagerInterface $config_manager
   *   The config manager.
   * @param \Drupal\system\FileDownloadController $file_download_controller
   *   The file download controller.
   * @param \Drupal\Core\Diff\DiffFormatter $diff_formatter
   *   The diff formatter.
   * @param \Drupal\Core\File\FileSystemInterface $file_system
   *   The file system.
   * @param \Drupal\Core\Config\StorageInterface $export_storage
   *   The export storage.
   * @param \Drupal\Core\Config\ImportStorageTransformer $import_transformer
   *   The import transformer service.
   */
  public function __construct(StorageInterface $target_storage, StorageInterface $sync_storage, ConfigManagerInterface $config_manager, FileDownloadController $file_download_controller, DiffFormatter $diff_formatter, FileSystemInterface $file_system, StorageInterface $export_storage, ImportStorageTransformer $import_transformer) {
    $this->targetStorage = $target_storage;
    $this->syncStorage = $sync_storage;
    $this->configManager = $config_manager;
    $this->fileDownloadController = $file_download_controller;
    $this->diffFormatter = $diff_formatter;
    $this->fileSystem = $file_system;
    $this->exportStorage = $export_storage;
    $this->importTransformer = $import_transformer;
  }

  /**
   * Downloads a tarball of the site configuration.
   */
  public function downloadExport() {
    try {
      $this->fileSystem
        ->delete($this->fileSystem
        ->getTempDirectory() . '/config.tar.gz');
    } catch (FileException $e) {

      // Ignore failed deletes.
    }
    $archiver = new ArchiveTar($this->fileSystem
      ->getTempDirectory() . '/config.tar.gz', 'gz');

    // Add all contents of the export storage to the archive.
    foreach ($this->exportStorage
      ->listAll() as $name) {
      $archiver
        ->addString("{$name}.yml", Yaml::encode($this->exportStorage
        ->read($name)));
    }

    // Get all  data from the remaining collections.
    foreach ($this->exportStorage
      ->getAllCollectionNames() as $collection) {
      $collection_storage = $this->exportStorage
        ->createCollection($collection);
      foreach ($collection_storage
        ->listAll() as $name) {
        $archiver
          ->addString(str_replace('.', '/', $collection) . "/{$name}.yml", Yaml::encode($collection_storage
          ->read($name)));
      }
    }
    $request = new Request([
      'file' => 'config.tar.gz',
    ]);
    return $this->fileDownloadController
      ->download($request, 'temporary');
  }

  /**
   * Shows diff of specified configuration file.
   *
   * @param string $source_name
   *   The name of the configuration file.
   * @param string $target_name
   *   (optional) The name of the target configuration file if different from
   *   the $source_name.
   * @param string $collection
   *   (optional) The configuration collection name. Defaults to the default
   *   collection.
   *
   * @return array
   *   Table showing a two-way diff between the active and staged configuration.
   */
  public function diff($source_name, $target_name = NULL, $collection = NULL) {
    if (!isset($collection)) {
      $collection = StorageInterface::DEFAULT_COLLECTION;
    }
    $syncStorage = $this->importTransformer
      ->transform($this->syncStorage);
    $diff = $this->configManager
      ->diff($this->targetStorage, $syncStorage, $source_name, $target_name, $collection);
    $this->diffFormatter->show_header = FALSE;
    $build = [];
    $build['#title'] = $this
      ->t('View changes of @config_file', [
      '@config_file' => $source_name,
    ]);

    // Add the CSS for the inline diff.
    $build['#attached']['library'][] = 'system/diff';
    $build['diff'] = [
      '#type' => 'table',
      '#attributes' => [
        'class' => [
          'diff',
        ],
      ],
      '#header' => [
        [
          'data' => $this
            ->t('Active'),
          'colspan' => '2',
        ],
        [
          'data' => $this
            ->t('Staged'),
          'colspan' => '2',
        ],
      ],
      '#rows' => $this->diffFormatter
        ->format($diff),
    ];
    $build['back'] = [
      '#type' => 'link',
      '#attributes' => [
        'class' => [
          'dialog-cancel',
        ],
      ],
      '#title' => "Back to 'Synchronize configuration' page.",
      '#url' => Url::fromRoute('config.sync'),
    ];
    return $build;
  }

}