class ImageStyle

class ImageStyle extends ConfigEntityBase implements ImageStyleInterface, EntityWithPluginCollectionInterface {
  
  /**
   * The name of the image style.
   *
   * @var string
   */
  protected $name;
  
  /**
   * The image style label.
   *
   * @var string
   */
  protected $label;
  
  /**
   * The array of image effects for this image style.
   *
   * @var array
   */
  protected $effects = [];
  
  /**
   * Holds the collection of image effects that are used by this image style.
   *
   * @var \Drupal\image\ImageEffectPluginCollection
   */
  protected $effectsCollection;
  
  /**
   * {@inheritdoc}
   */
  public function id() {
    return $this->name;
  }
  
  /**
   * {@inheritdoc}
   */
  public function postSave(EntityStorageInterface $storage, $update = TRUE) {
    parent::postSave($storage, $update);
    if ($update) {
      if ($this->getOriginal() && $this->id() !== $this->getOriginal()
        ->id()) {
        // The old image style name needs flushing after a rename.
        $this->getOriginal()
          ->flush();
        // Update field settings if necessary.
        if (!$this->isSyncing()) {
          static::replaceImageStyle($this);
        }
      }
      else {
        // Flush image style when updating without changing the name.
        $this->flush();
      }
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public static function postDelete(EntityStorageInterface $storage, array $entities) {
    parent::postDelete($storage, $entities);
    /** @var \Drupal\image\ImageStyleInterface[] $entities */
    foreach ($entities as $style) {
      // Flush cached media for the deleted style.
      $style->flush();
      // Clear the replacement ID, if one has been previously stored.
      /** @var \Drupal\image\ImageStyleStorageInterface $storage */
      $storage->clearReplacementId($style->id());
    }
  }
  
  /**
   * Update field settings if the image style name is changed.
   *
   * @param \Drupal\image\ImageStyleInterface $style
   *   The image style.
   */
  protected static function replaceImageStyle(ImageStyleInterface $style) {
    if ($style->id() != $style->getOriginalId()) {
      // Loop through all entity displays looking for formatters / widgets using
      // the image style.
      foreach (EntityViewDisplay::loadMultiple() as $display) {
        foreach ($display->getComponents() as $name => $options) {
          if (isset($options['type']) && $options['type'] == 'image' && $options['settings']['image_style'] == $style->getOriginalId()) {
            $options['settings']['image_style'] = $style->id();
            $display->setComponent($name, $options)
              ->save();
          }
        }
      }
      foreach (EntityFormDisplay::loadMultiple() as $display) {
        foreach ($display->getComponents() as $name => $options) {
          if (isset($options['type']) && $options['type'] == 'image_image' && $options['settings']['preview_image_style'] == $style->getOriginalId()) {
            $options['settings']['preview_image_style'] = $style->id();
            $display->setComponent($name, $options)
              ->save();
          }
        }
      }
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildUri($uri) {
    $source_scheme = $scheme = StreamWrapperManager::getScheme($uri);
    $default_scheme = $this->fileDefaultScheme();
    if ($source_scheme) {
      $path = StreamWrapperManager::getTarget($uri);
      // The scheme of derivative image files only needs to be computed for
      // source files not stored in the default scheme.
      if ($source_scheme != $default_scheme) {
        $class = $this->getStreamWrapperManager()
          ->getClass($source_scheme);
        $is_writable = NULL;
        if ($class) {
          $is_writable = $class::getType() & StreamWrapperInterface::WRITE;
        }
        // Compute the derivative URI scheme. Derivatives created from writable
        // source stream wrappers will inherit the scheme. Derivatives created
        // from read-only stream wrappers will fall-back to the default scheme.
        $scheme = $is_writable ? $source_scheme : $default_scheme;
      }
    }
    else {
      $path = $uri;
      $source_scheme = $scheme = $default_scheme;
    }
    return "{$scheme}://styles/{$this->id()}/{$source_scheme}/{$this->addExtension($path)}";
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildUrl($path, $clean_urls = NULL) {
    /** @var \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface $stream_wrapper_manager */
    $stream_wrapper_manager = \Drupal::service('stream_wrapper_manager');
    $uri = $stream_wrapper_manager->normalizeUri($this->buildUri($path));
    // The token query is added even if the
    // 'image.settings:allow_insecure_derivatives' configuration is TRUE, so
    // that the emitted links remain valid if it is changed back to the default
    // FALSE. However, sites which need to prevent the token query from being
    // emitted at all can additionally set the
    // 'image.settings:suppress_itok_output' configuration to TRUE to achieve
    // that (if both are set, the security token will neither be emitted in the
    // image derivative URL nor checked for in
    // \Drupal\image\ImageStyleInterface::deliver()).
    $token_query = [];
    if (!\Drupal::config('image.settings')->get('suppress_itok_output')) {
      // The passed $path variable can be either a relative path or a full URI.
      if (!$stream_wrapper_manager::getScheme($path)) {
        $path = \Drupal::config('system.file')->get('default_scheme') . '://' . $path;
      }
      $original_uri = $stream_wrapper_manager->normalizeUri($path);
      $token_query = [
        IMAGE_DERIVATIVE_TOKEN => $this->getPathToken($original_uri),
      ];
    }
    if ($clean_urls === NULL) {
      // Assume clean URLs unless the request tells us otherwise.
      $clean_urls = TRUE;
      try {
        $request = \Drupal::request();
        $clean_urls = RequestHelper::isCleanUrl($request);
      } catch (ServiceNotFoundException) {
      }
    }
    // If not using clean URLs, the image derivative callback is only available
    // with the script path. If the file does not exist, use Url::fromUri() to
    // ensure that it is included. Once the file exists it's fine to fall back
    // to the actual file path, this avoids bootstrapping PHP once the files are
    // built.
    if ($clean_urls === FALSE && $stream_wrapper_manager::getScheme($uri) == 'public' && !file_exists($uri)) {
      $directory_path = $stream_wrapper_manager->getViaUri($uri)
        ->getDirectoryPath();
      return Url::fromUri('base:' . $directory_path . '/' . $stream_wrapper_manager::getTarget($uri), [
        'absolute' => TRUE,
        'query' => $token_query,
      ])->toString();
    }
    /** @var \Drupal\Core\File\FileUrlGeneratorInterface $file_url_generator */
    $file_url_generator = \Drupal::service('file_url_generator');
    $file_url = $file_url_generator->generateAbsoluteString($uri);
    // Append the query string with the token, if necessary.
    if ($token_query) {
      $file_url .= (str_contains($file_url, '?') ? '&' : '?') . UrlHelper::buildQuery($token_query);
    }
    return $file_url;
  }
  
  /**
   * {@inheritdoc}
   */
  public function flush($path = NULL) {
    // A specific image path has been provided. Flush only that derivative.
    /** @var \Drupal\Core\File\FileSystemInterface $file_system */
    $file_system = \Drupal::service('file_system');
    if (isset($path)) {
      $derivative_uri = $this->buildUri($path);
      if (file_exists($derivative_uri)) {
        try {
          $file_system->delete($derivative_uri);
        } catch (FileException) {
          // Ignore failed deletes.
        }
      }
    }
    else {
      // Delete the style directory in each registered wrapper.
      $wrappers = $this->getStreamWrapperManager()
        ->getWrappers(StreamWrapperInterface::WRITE_VISIBLE);
      foreach ($wrappers as $wrapper => $wrapper_data) {
        if (file_exists($directory = $wrapper . '://styles/' . $this->id())) {
          try {
            $file_system->deleteRecursive($directory);
          } catch (FileException) {
            // Ignore failed deletes.
          }
        }
      }
    }
    // Let other modules update as necessary on flush.
    $module_handler = \Drupal::moduleHandler();
    $module_handler->invokeAll('image_style_flush', [
      $this,
      $path,
    ]);
    // Clear caches when the complete image style is flushed,
    // so that field formatters may be added for this style.
    if (!isset($path)) {
      \Drupal::service('theme.registry')->reset();
      Cache::invalidateTags($this->getCacheTagsToInvalidate());
    }
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function createDerivative($original_uri, $derivative_uri) {
    // If the source file doesn't exist, return FALSE without creating folders.
    $image = $this->getImageFactory()
      ->get($original_uri);
    if (!$image->isValid()) {
      return FALSE;
    }
    // Get the folder for the final location of this style.
    $directory = \Drupal::service('file_system')->dirname($derivative_uri);
    // Build the destination folder tree if it doesn't already exist.
    if (!\Drupal::service('file_system')->prepareDirectory($directory, FileSystemInterface::CREATE_DIRECTORY | FileSystemInterface::MODIFY_PERMISSIONS)) {
      \Drupal::logger('image')->error('Failed to create style directory: %directory', [
        '%directory' => $directory,
      ]);
      return FALSE;
    }
    foreach ($this->getEffects() as $effect) {
      $effect->applyEffect($image);
    }
    if (!$image->save($derivative_uri)) {
      if (file_exists($derivative_uri)) {
        \Drupal::logger('image')->error('Cached image file %destination already exists. There may be an issue with your rewrite configuration.', [
          '%destination' => $derivative_uri,
        ]);
      }
      return FALSE;
    }
    return TRUE;
  }
  
  /**
   * {@inheritdoc}
   */
  public function transformDimensions(array &$dimensions, $uri) {
    foreach ($this->getEffects() as $effect) {
      $effect->transformDimensions($dimensions, $uri);
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function getDerivativeExtension($extension) {
    foreach ($this->getEffects() as $effect) {
      $extension = $effect->getDerivativeExtension($extension);
    }
    return $extension;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getPathToken($uri) {
    // Return the first 8 characters.
    return substr(Crypt::hmacBase64($this->id() . ':' . $this->addExtension($uri), $this->getPrivateKey() . $this->getHashSalt()), 0, 8);
  }
  
  /**
   * {@inheritdoc}
   */
  public function deleteImageEffect(ImageEffectInterface $effect) {
    $this->getEffects()
      ->removeInstanceId($effect->getUuid());
    $this->save();
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function supportsUri($uri) {
    // Only support the URI if its extension is supported by the current image
    // toolkit.
    return in_array(mb_strtolower(pathinfo($uri, PATHINFO_EXTENSION)), $this->getImageFactory()
      ->getSupportedExtensions());
  }
  
  /**
   * {@inheritdoc}
   */
  public function getEffect($effect) {
    return $this->getEffects()
      ->get($effect);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getEffects() {
    if (!$this->effectsCollection) {
      $this->effectsCollection = new ImageEffectPluginCollection($this->getImageEffectPluginManager(), $this->effects);
      $this->effectsCollection
        ->sort();
    }
    return $this->effectsCollection;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getPluginCollections() {
    return [
      'effects' => $this->getEffects(),
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function addImageEffect(array $configuration) {
    $configuration['uuid'] = $this->uuidGenerator()
      ->generate();
    $this->getEffects()
      ->addInstanceId($configuration['uuid'], $configuration);
    return $configuration['uuid'];
  }
  
  /**
   * {@inheritdoc}
   */
  public function getReplacementID() {
    /** @var \Drupal\image\ImageStyleStorageInterface $storage */
    $storage = $this->entityTypeManager()
      ->getStorage($this->getEntityTypeId());
    return $storage->getReplacementId($this->id());
  }
  
  /**
   * {@inheritdoc}
   */
  public function getName() {
    return $this->get('name');
  }
  
  /**
   * {@inheritdoc}
   */
  public function setName($name) {
    $this->set('name', $name);
    return $this;
  }
  
  /**
   * Returns the image effect plugin manager.
   *
   * @return \Drupal\Component\Plugin\PluginManagerInterface
   *   The image effect plugin manager.
   */
  protected function getImageEffectPluginManager() {
    return \Drupal::service('plugin.manager.image.effect');
  }
  
  /**
   * Returns the image factory.
   *
   * @return \Drupal\Core\Image\ImageFactory
   *   The image factory.
   */
  protected function getImageFactory() {
    return \Drupal::service('image.factory');
  }
  
  /**
   * Gets the Drupal private key.
   *
   * @return string
   *   The Drupal private key.
   */
  protected function getPrivateKey() {
    return \Drupal::service('private_key')->get();
  }
  
  /**
   * Gets a salt useful for hardening against SQL injection.
   *
   * @return string
   *   A salt based on information in settings.php, not in the database.
   *
   * @throws \RuntimeException
   */
  protected function getHashSalt() {
    return Settings::getHashSalt();
  }
  
  /**
   * Adds an extension to a path.
   *
   * If this image style changes the extension of the derivative, this method
   * adds the new extension to the given path. This way we avoid filename
   * clashes while still allowing us to find the source image.
   *
   * @param string $path
   *   The path to add the extension to.
   *
   * @return string
   *   The given path if this image style doesn't change its extension, or the
   *   path with the added extension if it does.
   */
  protected function addExtension($path) {
    $original_extension = pathinfo($path, PATHINFO_EXTENSION);
    $extension = $this->getDerivativeExtension($original_extension);
    if ($original_extension !== $extension) {
      $path .= '.' . $extension;
    }
    return $path;
  }
  
  /**
   * Provides a wrapper to allow unit testing.
   *
   * Gets the default file stream implementation.
   *
   * @return string
   *   'public', 'private' or any other file scheme defined as the default.
   */
  protected function fileDefaultScheme() {
    return \Drupal::config('system.file')->get('default_scheme');
  }
  
  /**
   * Gets the stream wrapper manager service.
   *
   * @return \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface
   *   The stream wrapper manager service
   *
   * @todo Properly inject this service in Drupal 9.0.x.
   */
  protected function getStreamWrapperManager() {
    return \Drupal::service('stream_wrapper_manager');
  }

}