class FileRepository

class FileRepository implements FileRepositoryInterface {
    
    /**
     * The file system service.
     *
     * @var \Drupal\Core\File\FileSystemInterface
     */
    protected $fileSystem;
    
    /**
     * The stream wrapper manager.
     *
     * @var \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface
     */
    protected $streamWrapperManager;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The module handler.
     *
     * @var \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected $moduleHandler;
    
    /**
     * The file usage service.
     *
     * @var \Drupal\file\FileUsage\FileUsageInterface
     */
    protected $fileUsage;
    
    /**
     * The current user.
     *
     * @var \Drupal\Core\Session\AccountInterface
     */
    protected $currentUser;
    
    /**
     * FileRepository constructor.
     *
     * @param \Drupal\Core\File\FileSystemInterface $fileSystem
     *   The file system.
     * @param \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface $streamWrapperManager
     *   The stream wrapper manager.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entityTypeManager
     *   The entity type manager.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
     *   The module handler.
     * @param \Drupal\file\FileUsage\FileUsageInterface $fileUsage
     *   The file usage service.
     * @param \Drupal\Core\Session\AccountInterface $currentUser
     *   The current user.
     */
    public function __construct(FileSystemInterface $fileSystem, StreamWrapperManagerInterface $streamWrapperManager, EntityTypeManagerInterface $entityTypeManager, ModuleHandlerInterface $moduleHandler, FileUsageInterface $fileUsage, AccountInterface $currentUser) {
        $this->fileSystem = $fileSystem;
        $this->streamWrapperManager = $streamWrapperManager;
        $this->entityTypeManager = $entityTypeManager;
        $this->moduleHandler = $moduleHandler;
        $this->fileUsage = $fileUsage;
        $this->currentUser = $currentUser;
    }
    
    /**
     * {@inheritdoc}
     */
    public function writeData(string $data, string $destination, int $replace = FileSystemInterface::EXISTS_RENAME) : FileInterface {
        if (!$this->streamWrapperManager
            ->isValidUri($destination)) {
            throw new InvalidStreamWrapperException("Invalid stream wrapper: {$destination}");
        }
        $uri = $this->fileSystem
            ->saveData($data, $destination, $replace);
        return $this->createOrUpdate($uri, $destination, $replace === FileSystemInterface::EXISTS_RENAME);
    }
    
    /**
     * Create a file entity or update if it exists.
     *
     * @param string $uri
     *   The file URI.
     * @param string $destination
     *   The destination URI.
     * @param bool $rename
     *   Whether to rename the file.
     *
     * @return \Drupal\file\Entity\File|\Drupal\file\FileInterface
     *   The file entity.
     *
     * @throws \Drupal\Core\Entity\EntityStorageException
     *   Thrown when there is an error saving the file.
     */
    protected function createOrUpdate(string $uri, string $destination, bool $rename) : FileInterface {
        $file = $this->loadByUri($uri);
        if ($file === NULL) {
            $file = File::create([
                'uri' => $uri,
            ]);
            $file->setOwnerId($this->currentUser
                ->id());
        }
        if ($rename && is_file($destination)) {
            $file->setFilename($this->fileSystem
                ->basename($destination));
        }
        $file->setPermanent();
        $file->save();
        return $file;
    }
    
    /**
     * {@inheritdoc}
     */
    public function copy(FileInterface $source, string $destination, int $replace = FileSystemInterface::EXISTS_RENAME) : FileInterface {
        if (!$this->streamWrapperManager
            ->isValidUri($destination)) {
            throw new InvalidStreamWrapperException("Invalid stream wrapper: {$destination}");
        }
        $uri = $this->fileSystem
            ->copy($source->getFileUri(), $destination, $replace);
        // If we are replacing an existing file, load it.
        if ($replace === FileSystemInterface::EXISTS_REPLACE && ($existing = $this->loadByUri($uri))) {
            $file = $existing;
        }
        else {
            $file = $source->createDuplicate();
            $file->setFileUri($uri);
            // If we are renaming around an existing file (rather than a directory),
            // use its basename for the filename.
            if ($replace === FileSystemInterface::EXISTS_RENAME && is_file($destination)) {
                $file->setFilename($this->fileSystem
                    ->basename($destination));
            }
            else {
                $file->setFilename($this->fileSystem
                    ->basename($uri));
            }
        }
        $file->save();
        // Inform modules that the file has been copied.
        $this->moduleHandler
            ->invokeAll('file_copy', [
            $file,
            $source,
        ]);
        return $file;
    }
    
    /**
     * {@inheritdoc}
     */
    public function move(FileInterface $source, string $destination, int $replace = FileSystemInterface::EXISTS_RENAME) : FileInterface {
        if (!$this->streamWrapperManager
            ->isValidUri($destination)) {
            throw new InvalidStreamWrapperException("Invalid stream wrapper: {$destination}");
        }
        $uri = $this->fileSystem
            ->move($source->getFileUri(), $destination, $replace);
        $delete_source = FALSE;
        $file = clone $source;
        $file->setFileUri($uri);
        // If we are replacing an existing file re-use its database record.
        if ($replace === FileSystemInterface::EXISTS_REPLACE) {
            if ($existing = $this->loadByUri($uri)) {
                $delete_source = TRUE;
                $file->fid = $existing->id();
                $file->uuid = $existing->uuid();
            }
        }
        elseif ($replace === FileSystemInterface::EXISTS_RENAME && is_file($destination)) {
            $file->setFilename($this->fileSystem
                ->basename($destination));
        }
        $file->save();
        // Inform modules that the file has been moved.
        $this->moduleHandler
            ->invokeAll('file_move', [
            $file,
            $source,
        ]);
        // Delete the original if it's not in use elsewhere.
        if ($delete_source && !$this->fileUsage
            ->listUsage($source)) {
            $source->delete();
        }
        return $file;
    }
    
    /**
     * {@inheritdoc}
     */
    public function loadByUri(string $uri) : ?FileInterface {
        $fileStorage = $this->entityTypeManager
            ->getStorage('file');
        
        /** @var \Drupal\file\FileInterface[] $files */
        $files = $fileStorage->loadByProperties([
            'uri' => $uri,
        ]);
        if (count($files)) {
            foreach ($files as $item) {
                // Since some database servers sometimes use a case-insensitive
                // comparison by default, double check that the filename is an exact
                // match.
                if ($item->getFileUri() === $uri) {
                    return $item;
                }
            }
        }
        return NULL;
    }

}