import logging

from peewee import JOIN_LEFT_OUTER, fn
from datetime import timedelta, datetime

from data.model import (DataModelException, tag, db_transaction, storage, image, permission,
                        _basequery)
from data.database import (Repository, Namespace, RepositoryTag, Star, Image, ImageStorage, User,
                           Visibility, RepositoryPermission, TupleSelector, RepositoryActionCount,
                           Role, RepositoryAuthorizedEmail, db_for_update)


logger = logging.getLogger(__name__)


def create_repository(namespace, name, creating_user, visibility='private'):
  private = Visibility.get(name=visibility)
  namespace_user = User.get(username=namespace)
  repo = Repository.create(name=name, visibility=private, namespace_user=namespace_user)
  admin = Role.get(name='admin')

  if creating_user and not creating_user.organization:
    RepositoryPermission.create(user=creating_user, repository=repo, role=admin)

    if creating_user.username != namespace:
      # Permission prototypes only work for orgs
      permission.apply_default_permissions(repo, creating_user)
  return repo


def get_repository(namespace_name, repository_name):
  try:
    return _basequery.get_existing_repository(namespace_name, repository_name)
  except Repository.DoesNotExist:
    return None


def _purge_all_repository_tags(namespace_name, repository_name):
  """ Immediately purge all repository tags without respecting the lifeline procedure """
  try:
    repo = _basequery.get_existing_repository(namespace_name, repository_name)
  except Repository.DoesNotExist:
    raise DataModelException('Invalid repository \'%s/%s\'' %
                             (namespace_name, repository_name))
  RepositoryTag.delete().where(RepositoryTag.repository == repo.id).execute()


def purge_repository(namespace_name, repository_name):
  # Delete all tags to allow gc to reclaim storage
  _purge_all_repository_tags(namespace_name, repository_name)

  # Gc to remove the images and storage
  garbage_collect_repository(namespace_name, repository_name)

  # Delete the rest of the repository metadata
  fetched = _basequery.get_existing_repository(namespace_name, repository_name)
  fetched.delete_instance(recursive=True, delete_nullable=False)


def garbage_collect_repository(namespace_name, repository_name):
  storage_id_whitelist = {}

  tag.garbage_collect_tags(namespace_name, repository_name)

  with db_transaction():
    # TODO (jake): We could probably select this and all the images in a single query using
    # a different kind of join.

    # Get a list of all images used by tags in the repository
    tag_query = (RepositoryTag
                 .select(RepositoryTag, Image, ImageStorage)
                 .join(Image)
                 .join(ImageStorage, JOIN_LEFT_OUTER)
                 .switch(RepositoryTag)
                 .join(Repository)
                 .join(Namespace, on=(Repository.namespace_user == Namespace.id))
                 .where(Repository.name == repository_name, Namespace.username == namespace_name))

    referenced_ancestors = set()
    for one_tag in tag_query:
      # The ancestor list is in the format '/1/2/3/', extract just the ids
      ancestor_id_strings = one_tag.image.ancestors.split('/')[1:-1]
      ancestor_list = [int(img_id_str) for img_id_str in ancestor_id_strings]
      referenced_ancestors = referenced_ancestors.union(set(ancestor_list))
      referenced_ancestors.add(one_tag.image.id)

    all_repo_images = image.get_repository_images(namespace_name, repository_name)
    all_images = {int(img.id): img for img in all_repo_images}
    to_remove = set(all_images.keys()).difference(referenced_ancestors)

    if len(to_remove) > 0:
      logger.info('Cleaning up unreferenced images: %s', to_remove)
      storage_id_whitelist = {all_images[to_remove_id].storage.id for to_remove_id in to_remove}
      Image.delete().where(Image.id << list(to_remove)).execute()

  if len(to_remove) > 0:
    logger.info('Garbage collecting storage for images: %s', to_remove)
    storage.garbage_collect_storage(storage_id_whitelist)


def star_repository(user, repository):
  """ Stars a repository. """
  star = Star.create(user=user.id, repository=repository.id)
  star.save()


def unstar_repository(user, repository):
  """ Unstars a repository. """
  try:
    (Star
     .delete()
     .where(Star.repository == repository.id, Star.user == user.id)
     .execute())
  except Star.DoesNotExist:
    raise DataModelException('Star not found.')


def get_user_starred_repositories(user, limit=None, page=None):
  """ Retrieves all of the repositories a user has starred. """
  query = (Repository
           .select(Repository, User, Visibility)
           .join(Star)
           .switch(Repository)
           .join(User)
           .switch(Repository)
           .join(Visibility)
           .where(Star.user == user))

  if page and limit:
    query = query.paginate(page, limit)
  elif limit:
    query = query.limit(limit)

  return query


def repository_is_starred(user, repository):
  """ Determines whether a user has starred a repository or not. """
  try:
    (Star
     .select()
     .where(Star.repository == repository.id, Star.user == user.id)
     .get())
    return True
  except Star.DoesNotExist:
    return False


def get_when_last_modified(repository_ids):
  tuples = (RepositoryTag
            .select(RepositoryTag.repository, fn.Max(RepositoryTag.lifetime_start_ts))
            .where(RepositoryTag.repository << repository_ids)
            .group_by(RepositoryTag.repository)
            .tuples())

  last_modified_map = {}
  for record in tuples:
    last_modified_map[record[0]] = record[1]

  return last_modified_map


def get_action_counts(repository_ids):
  # Filter the join to recent entries only.
  last_week = datetime.now() - timedelta(weeks=1)
  tuples = (RepositoryActionCount
            .select(RepositoryActionCount.repository, fn.Sum(RepositoryActionCount.count))
            .where(RepositoryActionCount.repository << repository_ids)
            .where(RepositoryActionCount.date >= last_week)
            .group_by(RepositoryActionCount.repository)
            .tuples())

  action_count_map = {}
  for record in tuples:
    action_count_map[record[0]] = record[1]

  return action_count_map


def get_visible_repositories(username=None, include_public=True, page=None,
                             limit=None, namespace=None, namespace_only=False):
  fields = [Repository.name, Repository.id, Repository.description, Visibility.name,
            Namespace.username]

  query = _visible_repository_query(username=username, include_public=include_public, page=page,
                                    limit=limit, namespace=namespace,
                                    select_models=fields)

  if limit:
    query = query.limit(limit)

  if namespace and namespace_only:
    query = query.where(Namespace.username == namespace)

  return TupleSelector(query, fields)


def _visible_repository_query(username=None, include_public=True, limit=None,
                              page=None, namespace=None, select_models=[]):
  query = (Repository
           .select(*select_models)  # MySQL/RDS complains is there are selected models for counts.
           .distinct()
           .join(Visibility)
           .switch(Repository)
           .join(Namespace, on=(Repository.namespace_user == Namespace.id))
           .switch(Repository)
           .join(RepositoryPermission, JOIN_LEFT_OUTER))

  query = _basequery.filter_to_repos_for_user(query, username, namespace, include_public)
  if page:
    query = query.paginate(page, limit)
  elif limit:
    query = query.limit(limit)

  return query


def get_sorted_matching_repositories(prefix, only_public, checker, limit=10):
  """ Returns repositories matching the given prefix string and passing the given checker
      function.
  """
  last_week = datetime.now() - timedelta(weeks=1)
  results = []
  existing_ids = []

  def get_search_results(search_clause, with_count=False):
    if len(results) >= limit:
      return

    select_items = [Repository, Namespace]
    if with_count:
      select_items.append(fn.Sum(RepositoryActionCount.count).alias('count'))

    query = (Repository
             .select(*select_items)
             .join(Namespace, JOIN_LEFT_OUTER, on=(Namespace.id == Repository.namespace_user))
             .switch(Repository)
             .where(search_clause)
             .group_by(Repository, Namespace))

    if only_public:
      query = query.where(Repository.visibility == _basequery.get_public_repo_visibility())

    if existing_ids:
      query = query.where(~(Repository.id << existing_ids))

    if with_count:
      query = (query
               .switch(Repository)
               .join(RepositoryActionCount)
               .where(RepositoryActionCount.date >= last_week)
               .order_by(fn.Sum(RepositoryActionCount.count).desc()))

    for result in query:
      if len(results) >= limit:
        return results

      # Note: We compare IDs here, instead of objects, because calling .visibility on the
      # Repository will kick off a new SQL query to retrieve that visibility enum value. We don't
      # join the visibility table in SQL, as well, because it is ungodly slow in MySQL :-/
      result.is_public = result.visibility_id == _basequery.get_public_repo_visibility().id
      result.count = result.count if with_count else 0

      if not checker(result):
        continue

      results.append(result)
      existing_ids.append(result.id)

  # For performance reasons, we conduct the repo name and repo namespace searches on their
  # own. This also affords us the ability to give higher precedence to repository names matching
  # over namespaces, which is semantically correct.
  get_search_results(Repository.name ** (prefix + '%'), with_count=True)
  get_search_results(Repository.name ** (prefix + '%'), with_count=False)

  get_search_results(Namespace.username ** (prefix + '%'), with_count=True)
  get_search_results(Namespace.username ** (prefix + '%'), with_count=False)

  return results


def get_matching_repositories(repo_term, username=None, limit=10, include_public=True):
  namespace_term = repo_term
  name_term = repo_term

  visible = _visible_repository_query(username, include_public=include_public)

  search_clauses = (Repository.name ** ('%' + name_term + '%') |
                    Namespace.username ** ('%' + namespace_term + '%'))

  # Handle the case where the user has already entered a namespace path.
  if repo_term.find('/') > 0:
    parts = repo_term.split('/', 1)
    namespace_term = '/'.join(parts[:-1])
    name_term = parts[-1]

    search_clauses = (Repository.name ** ('%' + name_term + '%') &
                      Namespace.username ** ('%' + namespace_term + '%'))

  return visible.where(search_clauses).limit(limit)


def lookup_repository(repo_id):
  try:
    return Repository.get(Repository.id == repo_id)
  except Repository.DoesNotExist:
    return None


def is_repository_public(repository):
  return repository.visibility == _basequery.get_public_repo_visibility()


def repository_is_public(namespace_name, repository_name):
  try:
    (Repository
     .select()
     .join(Namespace, on=(Repository.namespace_user == Namespace.id))
     .switch(Repository)
     .join(Visibility)
     .where(Namespace.username == namespace_name, Repository.name == repository_name,
            Visibility.name == 'public')
     .get())
    return True
  except Repository.DoesNotExist:
    return False


def set_repository_visibility(repo, visibility):
  visibility_obj = Visibility.get(name=visibility)
  if not visibility_obj:
    return

  repo.visibility = visibility_obj
  repo.save()


def get_email_authorized_for_repo(namespace, repository, email):
  try:
    return (RepositoryAuthorizedEmail
            .select(RepositoryAuthorizedEmail, Repository, Namespace)
            .join(Repository)
            .join(Namespace, on=(Repository.namespace_user == Namespace.id))
            .where(Namespace.username == namespace, Repository.name == repository,
                   RepositoryAuthorizedEmail.email == email)
            .get())
  except RepositoryAuthorizedEmail.DoesNotExist:
    return None


def create_email_authorization_for_repo(namespace_name, repository_name, email):
  try:
    repo = _basequery.get_existing_repository(namespace_name, repository_name)
  except Repository.DoesNotExist:
    raise DataModelException('Invalid repository %s/%s' %
                             (namespace_name, repository_name))

  return RepositoryAuthorizedEmail.create(repository=repo, email=email, confirmed=False)


def confirm_email_authorization_for_repo(code):
  try:
    found = (RepositoryAuthorizedEmail
             .select(RepositoryAuthorizedEmail, Repository, Namespace)
             .join(Repository)
             .join(Namespace, on=(Repository.namespace_user == Namespace.id))
             .where(RepositoryAuthorizedEmail.code == code)
             .get())
  except RepositoryAuthorizedEmail.DoesNotExist:
    raise DataModelException('Invalid confirmation code.')

  found.confirmed = True
  found.save()

  return found