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 (!empty($this->original) && $this->id() !== $this->original
                ->id()) {
                // The old image style name needs flushing after a rename.
                $this->original
                    ->flush();
                // Update field settings if necessary.
                if (!$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 $e) {
            }
        }
        // If not using clean URLs, the image derivative callback is only available
        // with the script path. If the file does not exist, use Url::fromUri() to
        // ensure that it is included. Once the file exists it's fine to fall back
        // to the actual file path, this avoids bootstrapping PHP once the files are
        // built.
        if ($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) {
            $file_url .= (strpos($file_url, '?') !== FALSE ? '&' : '?') . 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 $e) {
                    // Ignore failed deletes.
                }
            }
            return $this;
        }
        // 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 $e) {
                    // Ignore failed deletes.
                }
            }
        }
        // Let other modules update as necessary on flush.
        $module_handler = \Drupal::moduleHandler();
        $module_handler->invokeAll('image_style_flush', [
            $this,
        ]);
        // Clear caches so that formatters may be added for this style.
        drupal_theme_rebuild();
        Cache::invalidateTags($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');
    }

}