class FileCopy

class FileCopy extends FileProcessBase implements ContainerFactoryPluginInterface {
    
    /**
     * The stream wrapper manager service.
     *
     * @var \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface
     */
    protected $streamWrapperManager;
    
    /**
     * The file system service.
     *
     * @var \Drupal\Core\File\FileSystemInterface
     */
    protected $fileSystem;
    
    /**
     * An instance of the download process plugin.
     *
     * @var \Drupal\migrate\Plugin\MigrateProcessInterface
     */
    protected $downloadPlugin;
    
    /**
     * Constructs a file_copy process plugin.
     *
     * @param array $configuration
     *   The plugin configuration.
     * @param string $plugin_id
     *   The plugin ID.
     * @param array $plugin_definition
     *   The plugin definition.
     * @param \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface $stream_wrappers
     *   The stream wrapper manager service.
     * @param \Drupal\Core\File\FileSystemInterface $file_system
     *   The file system service.
     * @param \Drupal\migrate\Plugin\MigrateProcessInterface $download_plugin
     *   An instance of the download plugin for handling remote URIs.
     */
    public function __construct(array $configuration, $plugin_id, array $plugin_definition, StreamWrapperManagerInterface $stream_wrappers, FileSystemInterface $file_system, MigrateProcessInterface $download_plugin) {
        $configuration += [
            'move' => FALSE,
        ];
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->streamWrapperManager = $stream_wrappers;
        $this->fileSystem = $file_system;
        $this->downloadPlugin = $download_plugin;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('stream_wrapper_manager'), $container->get('file_system'), $container->get('plugin.manager.migrate.process')
            ->createInstance('download', $configuration));
    }
    
    /**
     * {@inheritdoc}
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        // If we're stubbing a file entity, return a URI of NULL so it will get
        // stubbed by the general process.
        if ($row->isStub()) {
            return NULL;
        }
        [
            $source,
            $destination,
        ] = $value;
        // If the source path or URI represents a remote resource, delegate to the
        // download plugin.
        if (!$this->isLocalUri($source)) {
            return $this->downloadPlugin
                ->transform($value, $migrate_executable, $row, $destination_property);
        }
        // Ensure the source file exists, if it's a local URI or path.
        if (!file_exists($source)) {
            throw new MigrateException("File '{$source}' does not exist");
        }
        // If the start and end file is exactly the same, there is nothing to do.
        if ($this->isLocationUnchanged($source, $destination)) {
            return $destination;
        }
        // Check if a writable directory exists, and if not try to create it.
        $dir = $this->getDirectory($destination);
        // If the directory exists and is writable, avoid
        // \Drupal\Core\File\FileSystemInterface::prepareDirectory() call and write
        // the file to destination.
        if (!is_dir($dir) || !is_writable($dir)) {
            if (!$this->fileSystem
                ->prepareDirectory($dir, FileSystemInterface::CREATE_DIRECTORY | FileSystemInterface::MODIFY_PERMISSIONS)) {
                throw new MigrateException("Could not create or write to directory '{$dir}'");
            }
        }
        $final_destination = $this->writeFile($source, $destination, $this->configuration['file_exists']);
        if ($final_destination) {
            return $final_destination;
        }
        throw new MigrateException("File {$source} could not be copied to {$destination}");
    }
    
    /**
     * Tries to move or copy a file.
     *
     * @param string $source
     *   The source path or URI.
     * @param string $destination
     *   The destination path or URI.
     * @param int $replace
     *   (optional) FileSystemInterface::EXISTS_REPLACE (default) or
     *   FileSystemInterface::EXISTS_RENAME.
     *
     * @return string|bool
     *   File destination on success, FALSE on failure.
     */
    protected function writeFile($source, $destination, $replace = FileSystemInterface::EXISTS_REPLACE) {
        // Check if there is a destination available for copying. If there isn't,
        // it already exists at the destination and the replace flag tells us to not
        // replace it. In that case, return the original destination.
        if ($this->fileSystem
            ->getDestinationFilename($destination, $replace) === FALSE) {
            return $destination;
        }
        try {
            if ($this->configuration['move']) {
                return $this->fileSystem
                    ->move($source, $destination, $replace);
            }
            else {
                return $this->fileSystem
                    ->copy($source, $destination, $replace);
            }
        } catch (FileException $e) {
            return FALSE;
        }
    }
    
    /**
     * Returns the directory component of a URI or path.
     *
     * For URIs like public://foo.txt, the full physical path of public://
     * will be returned, since a scheme by itself will trip up certain file
     * API functions (such as
     * \Drupal\Core\File\FileSystemInterface::prepareDirectory()).
     *
     * @param string $uri
     *   The URI or path.
     *
     * @return string|false
     *   The directory component of the path or URI, or FALSE if it could not
     *   be determined.
     */
    protected function getDirectory($uri) {
        $dir = $this->fileSystem
            ->dirname($uri);
        if (substr($dir, -3) == '://') {
            return $this->fileSystem
                ->realpath($dir);
        }
        return $dir;
    }
    
    /**
     * Determines if the source and destination URIs represent identical paths.
     *
     * @param string $source
     *   The source URI.
     * @param string $destination
     *   The destination URI.
     *
     * @return bool
     *   TRUE if the source and destination URIs refer to the same physical path,
     *   otherwise FALSE.
     */
    protected function isLocationUnchanged($source, $destination) {
        return $this->fileSystem
            ->realpath($source) === $this->fileSystem
            ->realpath($destination);
    }
    
    /**
     * Determines if the given URI or path is considered local.
     *
     * A URI or path is considered local if it either has no scheme component,
     * or the scheme is implemented by a stream wrapper which extends
     * \Drupal\Core\StreamWrapper\LocalStream.
     *
     * @param string $uri
     *   The URI or path to test.
     *
     * @return bool
     */
    protected function isLocalUri($uri) {
        $scheme = StreamWrapperManager::getScheme($uri);
        // The vfs scheme is vfsStream, which is used in testing. vfsStream is a
        // simulated file system that exists only in memory, but should be treated
        // as a local resource.
        if ($scheme == 'vfs') {
            $scheme = FALSE;
        }
        return $scheme === FALSE || $this->streamWrapperManager
            ->getViaScheme($scheme) instanceof LocalStream;
    }

}