import logging
import hashlib
import json

from cnr.models.package_base import get_media_type

from data.database import db_transaction, MediaType
from data.appr_model import tag as tag_model


logger = logging.getLogger(__name__)


def _ensure_sha256_header(digest):
  if digest.startswith('sha256:'):
    return digest
  return 'sha256:' + digest


def _digest(manifestjson):
  return _ensure_sha256_header(hashlib.sha256(json.dumps(manifestjson, sort_keys=True)).hexdigest())


def get_manifest_query(digest, media_type, models_ref):
  Manifest = models_ref.Manifest
  return Manifest.select().where(Manifest.digest == _ensure_sha256_header(digest),
                                 Manifest.media_type == Manifest.media_type.get_id(media_type))


def get_manifest_with_blob(digest, media_type, models_ref):
  Blob = models_ref.Blob
  query = get_manifest_query(digest, media_type, models_ref)
  return query.join(Blob).get()


def get_or_create_manifest(manifest_json, media_type_name, models_ref):
  Manifest = models_ref.Manifest
  digest = _digest(manifest_json)
  try:
    manifest = get_manifest_query(digest, media_type_name, models_ref).get()
  except Manifest.DoesNotExist:
    with db_transaction():
      manifest = Manifest.create(digest=digest,
                                 manifest_json=manifest_json,
                                 media_type=Manifest.media_type.get_id(media_type_name))
  return manifest

def get_manifest_types(repo, models_ref, release=None):
  """ Returns an array of MediaTypes.name for a repo, can filter by tag """
  Tag = models_ref.Tag
  ManifestListManifest = models_ref.ManifestListManifest

  query = tag_model.tag_is_alive(Tag
                                  .select(MediaType.name)
                                  .join(ManifestListManifest,
                                        on=(ManifestListManifest.manifest_list == Tag.manifest_list))
                                  .join(MediaType,
                                        on=(ManifestListManifest.media_type == MediaType.id))
                                  .where(Tag.repository == repo,
                                         Tag.tag_kind == Tag.tag_kind.get_id('release')), Tag)
  if release:
    query = query.where(Tag.name == release)

  manifests = set()
  for m in query.distinct().tuples():
    manifests.add(get_media_type(m[0]))
  return manifests