import logging


from data.model import InvalidLabelKeyException, InvalidMediaTypeException, DataModelException
from data.database import (Label, Manifest, TagManifestLabel, MediaType, LabelSourceType,
                           db_transaction, ManifestLabel, TagManifestLabelMap,
                           TagManifestToManifest)
from data.text import prefix_search
from util.validation import validate_label_key
from util.validation import is_json

logger = logging.getLogger(__name__)

def list_manifest_labels(manifest_id, prefix_filter=None):
  """ Lists all labels found on the given manifest, with an optional filter by key prefix. """
  query = (Label
           .select(Label, MediaType)
           .join(MediaType)
           .switch(Label)
           .join(LabelSourceType)
           .switch(Label)
           .join(ManifestLabel)
           .where(ManifestLabel.manifest == manifest_id))

  if prefix_filter is not None:
    query = query.where(prefix_search(Label.key, prefix_filter))

  return query


def get_manifest_label(label_uuid, manifest):
  """ Retrieves the manifest label on the manifest with the given UUID or None if none. """
  try:
    return (Label
            .select(Label, LabelSourceType)
            .join(LabelSourceType)
            .where(Label.uuid == label_uuid)
            .switch(Label)
            .join(ManifestLabel)
            .where(ManifestLabel.manifest == manifest)
            .get())
  except Label.DoesNotExist:
    return None


def create_manifest_label(manifest_id, key, value, source_type_name, media_type_name=None):
  """ Creates a new manifest label on a specific tag manifest. """
  if not key:
    raise InvalidLabelKeyException()

  # Note that we don't prevent invalid label names coming from the manifest to be stored, as Docker
  # does not currently prevent them from being put into said manifests.
  if not validate_label_key(key) and source_type_name != 'manifest':
    raise InvalidLabelKeyException('Key `%s` is invalid' % key)

  # Find the matching media type. If none specified, we infer.
  if media_type_name is None:
    media_type_name = 'text/plain'
    if is_json(value):
      media_type_name = 'application/json'

  try:
    media_type_id = Label.media_type.get_id(media_type_name)
  except MediaType.DoesNotExist:
    raise InvalidMediaTypeException()

  source_type_id = Label.source_type.get_id(source_type_name)

  # Ensure the manifest exists.
  try:
    manifest = Manifest.get(id=manifest_id)
  except Manifest.DoesNotExist:
    return None

  with db_transaction():
    label = Label.create(key=key, value=value, source_type=source_type_id, media_type=media_type_id)
    manifest_label = ManifestLabel.create(manifest=manifest_id, label=label,
                                          repository=manifest.repository)

    # If there exists a mapping to a TagManifest, add the old-style label.
    # TODO(jschorr): Remove this code once the TagManifest table is gone.
    try:
      mapping_row = TagManifestToManifest.get(manifest=manifest)
      tag_manifest_label = TagManifestLabel.create(annotated=mapping_row.tag_manifest, label=label,
                                                   repository=manifest.repository)
      TagManifestLabelMap.create(manifest_label=manifest_label,
                                 tag_manifest_label=tag_manifest_label,
                                 label=label,
                                 manifest=manifest,
                                 tag_manifest=mapping_row.tag_manifest)
    except TagManifestToManifest.DoesNotExist:
      pass

  return label


def delete_manifest_label(label_uuid, manifest):
  """ Deletes the manifest label on the tag manifest with the given ID. Returns the label deleted
      or None if none.
  """
  # Find the label itself.
  label = get_manifest_label(label_uuid, manifest)
  if label is None:
    return None

  if not label.source_type.mutable:
    raise DataModelException('Cannot delete immutable label')

  # Delete the mapping records and label.
  # TODO(jschorr): Remove this code once the TagManifest table is gone.
  with db_transaction():
    (TagManifestLabelMap
     .delete()
     .where(TagManifestLabelMap.label == label)
     .execute())

    deleted_count = TagManifestLabel.delete().where(TagManifestLabel.label == label).execute()
    if deleted_count != 1:
      logger.warning('More than a single label deleted for matching label %s', label_uuid)

    deleted_count = ManifestLabel.delete().where(ManifestLabel.label == label).execute()
    if deleted_count != 1:
      logger.warning('More than a single label deleted for matching label %s', label_uuid)

    label.delete_instance(recursive=False)
    return label