@Service
public class FileService {

    private final Path uploadLocation;

    public FileService(ApplicationProperties properties) {
        this.uploadLocation = Paths.get(properties.getStorageConfiguration().getUploadDir());
    }

    public Path store(MultipartFile file) {
        String filename = StringUtils.cleanPath(file.getOriginalFilename());
        try {
            if (file.isEmpty()) {
                throw new StorageException("Failed to store empty file " + filename);
            }
            if (filename.contains("..")) {
                // This is a security check, should practically not happen as
                // cleanPath is handling that ...
                throw new StorageException("Cannot store file with relative path outside current directory " + filename);
            }
            try (InputStream inputStream = file.getInputStream()) {
                Path filePath = this.uploadLocation.resolve(filename);
                Files.copy(inputStream, filePath, StandardCopyOption.REPLACE_EXISTING);
                return filePath;
            }
        }
        catch (IOException e) {
            throw new StorageException("Failed to store file " + filename, e);
        }
    }

    public Resource loadAsResource(String filename) {
        try {
            Path file = load(filename);
            Resource resource = new UrlResource(file.toUri());
            if (resource.exists() || resource.isReadable()) {
                return resource;
            }
            else {
                throw new StorageFileNotFoundException("Could not read file: " + filename);

            }
        }
        catch (MalformedURLException e) {
            throw new StorageFileNotFoundException("Could not read file: " + filename, e);
        }
    }

    public Path load(String filename) {
        return uploadLocation.resolve(filename);
    }

    public Stream<Path> loadAll() {
        try {
            return Files.walk(this.uploadLocation, 1)
                    .filter(path -> !path.equals(this.uploadLocation))
                    .map(this.uploadLocation::relativize);
        }
        catch (IOException e) {
            throw new StorageException("Failed to read stored files", e);
        }

    }

    public void init() {
        try {
            Files.createDirectories(uploadLocation);
        }
        catch (IOException e) {
            throw new StorageException("Could not initialize storage", e);
        }
    }