import logging

from cachetools.func import lru_cache

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

logger = logging.getLogger(__name__)


@lru_cache(maxsize=1)
def get_label_source_types():
  source_type_map = {}
  for kind in LabelSourceType.select():
    source_type_map[kind.id] = kind.name
    source_type_map[kind.name] = kind.id

  return source_type_map


@lru_cache(maxsize=1)
def get_media_types():
  media_type_map = {}
  for kind in MediaType.select():
    media_type_map[kind.id] = kind.name
    media_type_map[kind.name] = kind.id

  return media_type_map


def _get_label_source_type_id(name):
  kinds = get_label_source_types()
  return kinds[name]


def _get_media_type_id(name):
  kinds = get_media_types()
  return kinds[name]


def create_manifest_label(tag_manifest, 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()

  # 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'

  media_type_id = _get_media_type_id(media_type_name)
  if media_type_id is None:
    raise InvalidMediaTypeException()

  source_type_id = _get_label_source_type_id(source_type_name)

  with db_transaction():
    label = Label.create(key=key, value=value, source_type=source_type_id, media_type=media_type_id)
    tag_manifest_label = TagManifestLabel.create(annotated=tag_manifest, label=label,
                                                 repository=tag_manifest.tag.repository)
    try:
      mapping_row = TagManifestToManifest.get(tag_manifest=tag_manifest)
      if mapping_row.manifest:
        manifest_label = ManifestLabel.create(manifest=mapping_row.manifest, label=label,
                                              repository=tag_manifest.tag.repository)
        TagManifestLabelMap.create(manifest_label=manifest_label,
                                   tag_manifest_label=tag_manifest_label,
                                   label=label,
                                   manifest=mapping_row.manifest,
                                   tag_manifest=tag_manifest)
    except TagManifestToManifest.DoesNotExist:
      pass

  return label


def list_manifest_labels(tag_manifest, prefix_filter=None):
  """ Lists all labels found on the given tag manifest. """
  query = (Label.select(Label, MediaType)
           .join(MediaType)
           .switch(Label)
           .join(LabelSourceType)
           .switch(Label)
           .join(TagManifestLabel)
           .where(TagManifestLabel.annotated == tag_manifest))

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

  return query


def get_manifest_label(label_uuid, tag_manifest):
  """ Retrieves the manifest label on the tag manifest with the given ID. """
  try:
    return (Label.select(Label, LabelSourceType)
            .join(LabelSourceType)
            .where(Label.uuid == label_uuid)
            .switch(Label)
            .join(TagManifestLabel)
            .where(TagManifestLabel.annotated == tag_manifest)
            .get())
  except Label.DoesNotExist:
    return None


def delete_manifest_label(label_uuid, tag_manifest):
  """ Deletes the manifest label on the tag manifest with the given ID. """

  # Find the label itself.
  label = get_manifest_label(label_uuid, tag_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.
  (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