from abc import ABCMeta, abstractmethod
from collections import namedtuple

from namedlist import namedlist
from peewee import IntegrityError
from six import add_metaclass

from data import model, database
from data.model import DataModelException
from image.docker.v1 import DockerV1Metadata

_MEDIA_TYPE = "application/vnd.docker.distribution.manifest.v1+prettyjws"


class Repository(namedtuple('Repository', ['id', 'name', 'namespace_name', 'description',
                                           'is_public'])):
  """
  Repository represents a namespaced collection of tags.
  """

class ManifestJSON(namedtuple('ManifestJSON', ['digest', 'json', 'media_type'])):
  """
  ManifestJSON represents a Manifest of any format.
  """


class Tag(namedtuple('Tag', ['name', 'repository'])):
  """
  Tag represents a user-facing alias for referencing a set of Manifests.
  """


class BlobUpload(namedlist('BlobUpload', ['uuid', 'byte_count', 'uncompressed_byte_count',
                                          'chunk_count', 'sha_state', 'location_name',
                                          'storage_metadata', 'piece_sha_state', 'piece_hashes',
                                          'repo_namespace_name', 'repo_name'])):
  """
  BlobUpload represents the current state of an Blob being uploaded.
  """


class Blob(namedtuple('Blob', ['uuid', 'digest', 'size', 'locations'])):
  """
  Blob represents an opaque binary blob saved to the storage system.
  """


class RepositoryReference(namedtuple('RepositoryReference', ['id', 'name', 'namespace_name'])):
  """
  RepositoryReference represents a reference to a Repository, without its full metadata.
  """

class Label(namedtuple('Label', ['key', 'value', 'source_type', 'media_type'])):
  """
  Label represents a key-value pair that describes a particular Manifest.
  """


@add_metaclass(ABCMeta)
class DockerRegistryV2DataInterface(object):
  """
  Interface that represents all data store interactions required by a Docker Registry v1.
  """

  @abstractmethod
  def create_repository(self, namespace_name, repo_name, creating_user=None):
    """
    Creates a new repository under the specified namespace with the given name. The user supplied is
    the user creating the repository, if any.
    """
    pass

  @abstractmethod
  def repository_is_public(self, namespace_name, repo_name):
    """
    Returns true if the repository with the given name under the given namespace has public
    visibility.
    """
    pass

  @abstractmethod
  def get_repository(self, namespace_name, repo_name):
    """
    Returns a repository tuple for the repository with the given name under the given namespace.
    Returns None if no such repository was found.
    """
    pass

  @abstractmethod
  def has_active_tag(self, namespace_name, repo_name, tag_name):
    """
    Returns whether there is an active tag for the tag with the given name under the matching
    repository, if any, or none if none.
    """
    pass

  @abstractmethod
  def get_manifest_by_tag(self, namespace_name, repo_name, tag_name):
    """
    Returns the current manifest for the tag with the given name under the matching repository, if
    any, or None if none.
    """
    pass

  @abstractmethod
  def get_manifest_by_digest(self, namespace_name, repo_name, digest):
    """
    Returns the manifest matching the given digest under the matching repository, if any, or None if
    none.
    """
    pass

  @abstractmethod
  def delete_manifest_by_digest(self, namespace_name, repo_name, digest):
    """
    Deletes the manifest with the associated digest (if any) and returns all removed tags that
    pointed to that manifest. If the manifest was not found, returns an empty list.
    """
    pass

  @abstractmethod
  def get_docker_v1_metadata_by_tag(self, namespace_name, repo_name, tag_name):
    """
    Returns the Docker V1 metadata associated with the tag with the given name under the matching
    repository, if any. If none, returns None.
    """
    pass

  @abstractmethod
  def get_docker_v1_metadata_by_image_id(self, namespace_name, repo_name, docker_image_ids):
    """
    Returns a map of Docker V1 metadata for each given image ID, matched under the repository with
    the given namespace and name. Returns an empty map if the matching repository was not found.
    """
    pass

  @abstractmethod
  def get_parents_docker_v1_metadata(self, namespace_name, repo_name, docker_image_id):
    """
    Returns an ordered list containing the Docker V1 metadata for each parent of the image with the
    given docker ID under the matching repository. Returns an empty list if the image was not found.
    """
    pass

  @abstractmethod
  def create_manifest_and_update_tag(self, namespace_name, repo_name, tag_name, manifest_digest,
                                     manifest_bytes):
    """
    Creates a new manifest with the given digest and byte data, and assigns the tag with the given
    name under the matching repository to it.
    """
    pass

  @abstractmethod
  def synthesize_v1_image(self, repository, storage, image_id, created, comment, command,
                          compat_json, parent_image_id):
    """
    Synthesizes a V1 image under the specified repository, pointing to the given storage and returns
    the V1 metadata for the synthesized image.
    """
    pass

  @abstractmethod
  def save_manifest(self, namespace_name, repo_name, tag_name, leaf_layer_docker_id,
                    manifest_digest, manifest_bytes):
    """
    Saves a manifest pointing to the given leaf image, with the given manifest, under the matching
    repository as a tag with the given name.

    Returns a boolean whether or not the tag was newly created or not.
    """
    pass

  @abstractmethod
  def repository_tags(self, namespace_name, repo_name, limit, offset):
    """
    Returns the active tags under the repository with the given name and namespace.
    """
    pass

  @abstractmethod
  def get_visible_repositories(self, username, limit, offset):
    """
    Returns the repositories visible to the user with the given username, if any.
    """
    pass

  @abstractmethod
  def create_blob_upload(self, namespace_name, repo_name, upload_uuid, location_name, storage_metadata):
    """
    Creates a blob upload under the matching repository with the given UUID and metadata.
    Returns whether the matching repository exists.
    """
    pass

  @abstractmethod
  def blob_upload_by_uuid(self, namespace_name, repo_name, upload_uuid):
    """
    Searches for a blob upload with the given UUID under the given repository and returns it or None
    if none.
    """
    pass

  @abstractmethod
  def update_blob_upload(self, blob_upload):
    """
    Saves any changes to the blob upload object given to the backing data store.
    Fields that can change:
      - uncompressed_byte_count
      - piece_hashes
      - piece_sha_state
      - storage_metadata
      - byte_count
      - chunk_count
      - sha_state
    """
    pass

  @abstractmethod
  def delete_blob_upload(self, namespace_name, repo_name, uuid):
    """
    Deletes the blob upload with the given uuid under the matching repository. If none, does
    nothing.
    """
    pass

  @abstractmethod
  def create_blob_and_temp_tag(self, namespace_name, repo_name, blob_digest, blob_upload,
                               expiration_sec):
    """
    Creates a blob and links a temporary tag with the specified expiration to it under the matching
    repository.
    """
    pass

  @abstractmethod
  def get_blob_by_digest(self, namespace_name, repo_name, digest):
    """
    Returns the blob with the given digest under the matching repository or None if none.
    """
    pass

  @abstractmethod
  def save_bittorrent_pieces(self, blob, piece_size, piece_bytes):
    """
    Saves the BitTorrent piece hashes for the given blob.
    """
    pass

  @abstractmethod
  def create_manifest_labels(self, namespace_name, repo_name, manifest_digest, labels):
    """
    Creates a new labels for the provided manifest.
    """
    pass


  @abstractmethod
  def get_blob_path(self, blob):
    """
    Once everything is moved over, this could be in util.registry and not even touch the database.
    """
    pass


class PreOCIModel(DockerRegistryV2DataInterface):
  """
  PreOCIModel implements the data model for the v2 Docker Registry protocol using a database schema
  before it was changed to support the OCI specification.
  """
  def create_repository(self, namespace_name, repo_name, creating_user=None):
    return model.repository.create_repository(namespace_name, repo_name, creating_user)

  def repository_is_public(self, namespace_name, repo_name):
    return model.repository.repository_is_public(namespace_name, repo_name)

  def get_repository(self, namespace_name, repo_name):
    repo = model.repository.get_repository(namespace_name, repo_name)
    if repo is None:
      return None
    return _repository_for_repo(repo)

  def has_active_tag(self, namespace_name, repo_name, tag_name):
    try:
      model.tag.get_active_tag(namespace_name, repo_name, tag_name)
      return True
    except database.RepositoryTag.DoesNotExist:
      return False

  def get_manifest_by_tag(self, namespace_name, repo_name, tag_name):
    try:
      manifest = model.tag.load_tag_manifest(namespace_name, repo_name, tag_name)
      return ManifestJSON(digest=manifest.digest, json=manifest.json_data, media_type=_MEDIA_TYPE)
    except model.InvalidManifestException:
      return None

  def get_manifest_by_digest(self, namespace_name, repo_name, digest):
    try:
      manifest = model.tag.load_manifest_by_digest(namespace_name, repo_name, digest)
      return ManifestJSON(digest=digest, json=manifest.json_data, media_type=_MEDIA_TYPE)
    except model.InvalidManifestException:
      return None

  def delete_manifest_by_digest(self, namespace_name, repo_name, digest):
    def _tag_view(tag):
      return Tag(
        name=tag.name,
        repository=RepositoryReference(
          id=tag.repository_id,
          name=repo_name,
          namespace_name=namespace_name,
        )
      )

    tags = model.tag.delete_manifest_by_digest(namespace_name, repo_name, digest)
    return [_tag_view(tag) for tag in tags]

  def get_docker_v1_metadata_by_tag(self, namespace_name, repo_name, tag_name):
    try:
      repo_img = model.tag.get_tag_image(namespace_name, repo_name, tag_name, include_storage=True)
      return _docker_v1_metadata(namespace_name, repo_name, repo_img)
    except DataModelException:
      return None

  def get_docker_v1_metadata_by_image_id(self, namespace_name, repo_name, docker_image_ids):
    repo = model.repository.get_repository(namespace_name, repo_name)
    if repo is None:
      return {}

    images_query = model.image.lookup_repository_images(repo, docker_image_ids)
    return {image.docker_image_id: _docker_v1_metadata(namespace_name, repo_name, image)
            for image in images_query}

  def get_parents_docker_v1_metadata(self, namespace_name, repo_name, docker_image_id):
    repo_image = model.image.get_repo_image(namespace_name, repo_name, docker_image_id)
    if repo_image is None:
      return []

    parents = model.image.get_parent_images(namespace_name, repo_name, repo_image)
    return [_docker_v1_metadata(namespace_name, repo_name, image) for image in parents]

  def create_manifest_and_update_tag(self, namespace_name, repo_name, tag_name, manifest_digest,
                                     manifest_bytes):
    try:
      model.tag.associate_generated_tag_manifest(namespace_name, repo_name, tag_name,
                                                 manifest_digest, manifest_bytes)
    except IntegrityError:
      # It's already there!
      pass

  def synthesize_v1_image(self, repository, storage, image_id, created, comment, command,
                          compat_json, parent_image_id):
    repo = model.repository.get_repository(repository.namespace_name, repository.name)
    if repo is None:
      raise DataModelException('Unknown repository: %s/%s' % (repository.namespace_name,
                                                              repository.name))

    parent_image = None
    if parent_image_id is not None:
      parent_image = model.image.get_image(repo, parent_image_id)
      if parent_image is None:
        raise DataModelException('Unknown parent image: %s' % parent_image_id)

    storage_obj = model.storage.get_storage_by_uuid(storage.uuid)
    if storage_obj is None:
      raise DataModelException('Unknown storage: %s' % storage.uuid)

    repo_image = model.image.synthesize_v1_image(repo, storage_obj, image_id, created, comment,
                                                 command, compat_json, parent_image)
    return _docker_v1_metadata(repo.namespace_user.username, repo.name, repo_image)

  def save_manifest(self, namespace_name, repo_name, tag_name, leaf_layer_docker_id,
                    manifest_digest, manifest_bytes):
    (_, newly_created) = model.tag.store_tag_manifest(namespace_name, repo_name, tag_name,
                                                      leaf_layer_docker_id, manifest_digest,
                                                      manifest_bytes)
    return newly_created

  def repository_tags(self, namespace_name, repo_name, limit, offset):
    def _tag_view(tag):
      return Tag(
        name=tag.name,
        repository=RepositoryReference(
          id=tag.repository_id,
          name=repo_name,
          namespace_name=namespace_name,
        )
      )

    tags_query = model.tag.list_repository_tags(namespace_name, repo_name)
    tags_query = tags_query.limit(limit).offset(offset)
    return [_tag_view(tag) for tag in tags_query]

  def get_visible_repositories(self, username, limit, offset):
    query = model.repository.get_visible_repositories(username, include_public=(username is None))
    query = query.limit(limit).offset(offset)
    return [_repository_for_repo(repo) for repo in query]

  def create_blob_upload(self, namespace_name, repo_name, upload_uuid, location_name, storage_metadata):
    try:
      model.blob.initiate_upload(namespace_name, repo_name, upload_uuid, location_name,
                                 storage_metadata)
      return True
    except database.Repository.DoesNotExist:
      return False

  def blob_upload_by_uuid(self, namespace_name, repo_name, upload_uuid):
    try:
      found = model.blob.get_blob_upload(namespace_name, repo_name, upload_uuid)
    except model.InvalidBlobUpload:
      return None

    return BlobUpload(
      repo_namespace_name=namespace_name,
      repo_name=repo_name,
      uuid=upload_uuid,
      byte_count=found.byte_count,
      uncompressed_byte_count=found.uncompressed_byte_count,
      chunk_count=found.chunk_count,
      sha_state=found.sha_state,
      piece_sha_state=found.piece_sha_state,
      piece_hashes=found.piece_hashes,
      location_name=found.location.name,
      storage_metadata=found.storage_metadata,
    )

  def update_blob_upload(self, blob_upload):
    # Lookup the blob upload object.
    try:
      blob_upload_record = model.blob.get_blob_upload(blob_upload.repo_namespace_name,
                                                      blob_upload.repo_name, blob_upload.uuid)
    except model.InvalidBlobUpload:
      return

    blob_upload_record.uncompressed_byte_count = blob_upload.uncompressed_byte_count
    blob_upload_record.piece_hashes = blob_upload.piece_hashes
    blob_upload_record.piece_sha_state = blob_upload.piece_sha_state
    blob_upload_record.storage_metadata = blob_upload.storage_metadata
    blob_upload_record.byte_count = blob_upload.byte_count
    blob_upload_record.chunk_count = blob_upload.chunk_count
    blob_upload_record.sha_state = blob_upload.sha_state
    blob_upload_record.save()

  def delete_blob_upload(self, namespace_name, repo_name, uuid):
    try:
      found = model.blob.get_blob_upload(namespace_name, repo_name, uuid)
      found.delete_instance()
    except model.InvalidBlobUpload:
      return

  def create_blob_and_temp_tag(self, namespace_name, repo_name, blob_digest, blob_upload,
                               expiration_sec):
    location_obj = model.storage.get_image_location_for_name(blob_upload.location_name)
    blob_record = model.blob.store_blob_record_and_temp_link(namespace_name, repo_name,
                                                             blob_digest, location_obj.id,
                                                             blob_upload.byte_count,
                                                             expiration_sec,
                                                             blob_upload.uncompressed_byte_count)
    return Blob(
      uuid=blob_record.uuid,
      digest=blob_digest,
      size=blob_upload.byte_count,
      locations=[blob_upload.location_name],
    )

  def lookup_blobs_by_digest(self, namespace_name, repo_name, digests):
    def _blob_view(blob_record):
      return Blob(
        uuid=blob_record.uuid,
        digest=blob_record.content_checksum,
        size=blob_record.image_size,
        locations=None, # Note: Locations is None in this case.
      )

    repo = model.repository.get_repository(namespace_name, repo_name)
    if repo is None:
      return {}
    query = model.storage.lookup_repo_storages_by_content_checksum(repo, digests)
    return {storage.content_checksum: _blob_view(storage) for storage in query}

  def get_blob_by_digest(self, namespace_name, repo_name, digest):
    try:
      blob_record = model.blob.get_repo_blob_by_digest(namespace_name, repo_name, digest)
      return Blob(
        uuid=blob_record.uuid,
        digest=digest,
        size=blob_record.image_size,
        locations=blob_record.locations,
      )
    except model.BlobDoesNotExist:
      return None

  def save_bittorrent_pieces(self, blob, piece_size, piece_bytes):
    blob_record = model.storage.get_storage_by_uuid(blob.uuid)
    model.storage.save_torrent_info(blob_record, piece_size, piece_bytes)

  def create_manifest_labels(self, namespace_name, repo_name, manifest_digest, labels):
    if not labels:
      # No point in doing anything more.
      return

    tag_manifest = model.tag.load_manifest_by_digest(namespace_name, repo_name, manifest_digest)
    for label in labels:
      model.label.create_manifest_label(tag_manifest, label.key, label.value, label.source_type,
                                        label.media_type)

  def get_blob_path(self, blob):
    blob_record = model.storage.get_storage_by_uuid(blob.uuid)
    return model.storage.get_layer_path(blob_record)


def _docker_v1_metadata(namespace_name, repo_name, repo_image):
  """
  Returns a DockerV1Metadata object for the given Pre-OCI repo_image under the
  repository with the given namespace and name. Note that the namespace and
  name are passed here as an optimization, and are *not checked* against the
  image.
  """
  return DockerV1Metadata(
    namespace_name=namespace_name,
    repo_name=repo_name,
    image_id=repo_image.docker_image_id,
    checksum=repo_image.v1_checksum,
    content_checksum=repo_image.storage.content_checksum,
    compat_json=repo_image.v1_json_metadata,
    created=repo_image.created,
    comment=repo_image.comment,
    command=repo_image.command,
    # TODO: make sure this isn't needed anywhere, as it is expensive to lookup
    parent_image_id=None,
  )


def _repository_for_repo(repo):
  """ Returns a Repository object representing the Pre-OCI data model repo instance given. """
  return Repository(
    id=repo.id,
    name=repo.name,
    namespace_name=repo.namespace_user.username,
    description=repo.description,
    is_public=model.repository.is_repository_public(repo)
  )


pre_oci_model = PreOCIModel()