import bisect

from appr.exception import PackageAlreadyExists
from appr.models.package_base import manifest_media_type

from data.database import (db_transaction, get_epoch_timestamp, Manifest, ManifestList, Tag,
                           ManifestListManifest, Blob, ManifestBlob)
from data.oci_model import (blob as blob_model, manifest as manifest_model,
                            manifest_list as manifest_list_model,
                            tag as tag_model)


# @TODO(ant31): cnr for retro-compat prepare a data migration
LIST_MEDIA_TYPE = 'application/vnd.cnr.manifest.list.v0.json'
SCHEMA_VERSION = 'v0'


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


def get_app_release(repo, tag_name, media_type):
  """ Returns (tag, manifest, blob) given a repo object, tag_name, and media_type). """
  tag = tag_model.get_tag(repo, tag_name, tag_kind='release')
  media_type_id = ManifestListManifest.media_type.get_id(manifest_media_type(media_type))
  manifestlistmanifest = (tag.manifest_list.manifestlistmanifest_set
                          .join(Manifest)
                          .where(ManifestListManifest.media_type == media_type_id).get())
  manifest = manifestlistmanifest.manifest
  blob = Blob.select().join(ManifestBlob).where(ManifestBlob.manifest == manifest).get()
  return (tag, manifest, blob)


def delete_app_release(repo, tag_name, media_type):
  """ Terminate a Tag/media-type couple
  It find the corresponding tag/manifest and remove from the manifestlistmanifest the manifest
  1. it terminates the current tag (in all-cases)
  2. if the new manifestlist is not empty, it creates a new tag for it
  """
  media_type_id = ManifestListManifest.media_type.get_id(manifest_media_type(media_type))

  with db_transaction():
    tag = tag_model.get_tag(repo, tag_name)
    manifest_list = tag.manifest_list
    list_json = manifest_list.manifest_list_json
    mlm_query = (ManifestListManifest
                 .select()
                 .where(ManifestListManifest.manifest_list == tag.manifest_list))
    list_manifest_ids = sorted([mlm.manifest_id for mlm in mlm_query])
    manifestlistmanifest = (tag
                            .manifest_list
                            .manifestlistmanifest_set
                            .where(ManifestListManifest.media_type == media_type_id).get())
    index = list_manifest_ids.index(manifestlistmanifest.manifest_id)
    list_manifest_ids.pop(index)
    list_json.pop(index)

    if not list_json:
      tag.lifetime_end = get_epoch_timestamp()
      tag.save()
    else:
      manifestlist = manifest_list_model.get_or_create_manifest_list(list_json, LIST_MEDIA_TYPE,
                                                                     SCHEMA_VERSION)
      manifest_list_model.create_manifestlistmanifest(manifestlist, list_manifest_ids,
                                                      list_json)
      tag = tag_model.create_or_update_tag(repo, tag_name, manifest_list=manifestlist,
                                           tag_kind="release")
    return tag


def create_app_release(repo, tag_name, manifest_data, digest, force=False):
  """ Create a new application release, it includes creating a new Tag, ManifestList,
      ManifestListManifests, Manifest, ManifestBlob.

      To deduplicate the ManifestList, the manifestlist_json is kept ordered by the manifest.id.
      To find the insert point in the ManifestList it uses bisect on the manifest-ids list.
  """
  with db_transaction():
    # Create/get the package manifest
    manifest = manifest_model.get_or_create_manifest(manifest_data, manifest_data['mediaType'])
    # get the tag
    tag = tag_model.get_or_initialize_tag(repo, tag_name)

    if tag.manifest_list is None:
      tag.manifest_list = ManifestList(media_type=ManifestList.media_type.get_id(LIST_MEDIA_TYPE),
                                       schema_version=SCHEMA_VERSION,
                                       manifest_list_json=[])

    elif tag_model.tag_media_type_exists(tag, manifest.media_type):
      if force:
        delete_app_release(repo, tag_name, manifest.media_type.name)
        return create_app_release(repo, tag_name, manifest_data, digest, force=False)
      else:
        raise PackageAlreadyExists("package exists already")

    list_json = tag.manifest_list.manifest_list_json
    mlm_query = (ManifestListManifest
                 .select()
                 .where(ManifestListManifest.manifest_list == tag.manifest_list))
    list_manifest_ids = sorted([mlm.manifest_id for mlm in mlm_query])
    insert_point = bisect.bisect_left(list_manifest_ids, manifest.id)
    list_json.insert(insert_point, manifest.manifest_json)
    list_manifest_ids.insert(insert_point, manifest.id)
    manifestlist = manifest_list_model.get_or_create_manifest_list(list_json, LIST_MEDIA_TYPE,
                                                                   SCHEMA_VERSION)
    manifest_list_model.create_manifestlistmanifest(manifestlist, list_manifest_ids, list_json)

    tag = tag_model.create_or_update_tag(repo, tag_name, manifest_list=manifestlist,
                                         tag_kind="release")
    blob_digest = digest

    try:
      (ManifestBlob
       .select()
       .join(Blob)
       .where(ManifestBlob.manifest == manifest,
              Blob.digest == _ensure_sha256_header(blob_digest)).get())
    except ManifestBlob.DoesNotExist:
      blob = blob_model.get_blob(blob_digest)
      ManifestBlob.create(manifest=manifest, blob=blob)
    return tag

def get_release_objs(repo, media_type=None):
  """ Returns an array of Tag for a repo, with optional filtering by media_type. """
  release_query = (Tag
                   .select()
                   .where(Tag.repository == repo,
                          Tag.tag_kind == Tag.tag_kind.get_id("release")))
  if media_type:
    release_query = tag_model.filter_tags_by_media_type(release_query, media_type)

  return tag_model.tag_alive_oci(release_query)

def get_releases(repo, media_type=None):
  """ Returns an array of Tag.name for a repo, can filter by media_type. """
  return [t.name for t in get_release_objs(repo, media_type)]