mixins.py

import logging
from math import ceil
from urllib import parse

from django.conf import settings
from django.core.exceptions import ValidationError
from django.core.paginator import Paginator
from django.db import transaction
from django.db.models import Q, F, QuerySet
from django.http import HttpResponseForbidden, Http404
from django.shortcuts import get_object_or_404
from django.urls import resolve, Resolver404
from django.utils.functional import cached_property
from pydash import compact, get
from rest_framework import status
from rest_framework.mixins import ListModelMixin, CreateModelMixin
from rest_framework.response import Response

from core.common.constants import HEAD, ACCESS_TYPE_NONE, INCLUDE_FACETS, \
    LIST_DEFAULT_LIMIT, HTTP_COMPRESS_HEADER, CSV_DEFAULT_LIMIT, FACETS_ONLY, INCLUDE_RETIRED_PARAM, \
    SEARCH_STATS_ONLY, INCLUDE_SEARCH_STATS, UPDATED_BY_USERNAME_PARAM, CHECKSUM_STANDARD_HEADER, \
    CHECKSUM_SMART_HEADER, SEARCH_LATEST_REPO_VERSION, SAME_STANDARD_CHECKSUM_ERROR
from core.common.permissions import HasPrivateAccess, HasOwnership, CanViewConceptDictionary, \
    CanViewConceptDictionaryVersion
from .checksums import ChecksumModel, Checksum
from .utils import write_csv_to_s3, get_csv_from_s3, get_query_params_from_url_string, compact_dict_by_values, \
    to_owner_uri, parse_updated_since_param, get_export_service, to_int, get_truthy_values, generate_temp_version
from ..concepts.constants import PERSIST_CLONE_ERROR
from ..toggles.models import Toggle

logger = logging.getLogger('oclapi')
TRUTHY = get_truthy_values()


class CustomPaginator:
    def __init__(  # pylint: disable=too-many-arguments
            self, request, total_count, queryset, page_size, is_sliced=False, max_score=None, search_scores=None,
            highlights=None
    ):
        self.request = request
        self.queryset = queryset
        self.total = total_count or (
            self.queryset.count() if isinstance(self.queryset, QuerySet) else len(self.queryset))
        self.page_size = int(page_size)
        self.page_number = to_int(request.GET.get('page', '1'), 1)
        if not is_sliced:
            bottom = (self.page_number - 1) * self.page_size
            top = bottom + self.page_size
            if top >= self.total:
                top = self.total
            self.queryset = self.queryset[bottom:top]
        if isinstance(self.queryset, QuerySet):
            self.queryset.count = None
        self.paginator = Paginator(self.queryset, self.page_size)
        self.page_object = self.paginator.get_page(self.page_number)
        self.page_count = ceil(int(self.total_count) / int(self.page_size))
        self.max_score = max_score
        self.search_scores = search_scores or {}
        self.highlights = highlights or {}

    @property
    def current_page_number(self):
        return self.page_number

    @property
    def current_page_results(self):
        results = self.page_object.object_list
        if self.search_scores or self.max_score or self.highlights:
            for result in results:
                result._score = self.search_scores.get(result.id)  # pylint: disable=protected-access
                result._highlight = self.highlights.get(result.id)  # pylint: disable=protected-access
                if result._score and self.max_score:  # pylint: disable=protected-access
                    result._confidence = f"{round((result._score / self.max_score) * 100, 2)}%"  # pylint: disable=protected-access
        return results

    @cached_property
    def total_count(self):
        return self.total

    def __get_query_params(self):
        return self.request.GET.copy()

    def __get_full_url(self):
        return self.request.build_absolute_uri('?')

    def get_next_page_url(self):
        query_params = self.__get_query_params()
        query_params['page'] = str(self.current_page_number + 1)
        return self.__get_full_url() + '?' + query_params.urlencode()

    def get_current_page_url(self):
        query_params = self.__get_query_params()
        query_params['page'] = str(self.current_page_number)
        return self.__get_full_url() + '?' + query_params.urlencode()

    def get_previous_page_url(self):
        query_params = self.__get_query_params()
        query_params['page'] = str(self.current_page_number - 1)
        return self.__get_full_url() + '?' + query_params.urlencode()

    def has_next(self):
        return self.page_number < self.page_count

    def has_previous(self):
        return self.page_number > 1

    @property
    def headers(self):
        headers = {
            'num_found': self.total_count,
            'num_returned': len(self.current_page_results),
            'pages': self.page_count,
            'page_number': self.page_number
        }
        if self.has_next():
            headers['next'] = self.get_next_page_url()
        if self.has_previous():
            headers['previous'] = self.get_previous_page_url()
        standard, smart = self.checksums
        if standard is not None:
            headers[CHECKSUM_STANDARD_HEADER] = standard
        if smart is not None:
            headers[CHECKSUM_SMART_HEADER] = smart
        return headers

    @property
    def checksums(self):
        standard, smart = [], []
        if get(self.current_page_results, '0.checksums.standard'):
            for result in self.current_page_results:
                standard.append(get(result.checksums, 'standard'))
                smart.append(get(result.checksums, 'smart'))
        standard = compact(standard)
        smart = compact(smart)
        standard = Checksum.generate(standard) if len(standard) > 1 else get(standard, '0')
        smart = Checksum.generate(smart) if len(smart) > 1 else get(smart, '0')
        return standard, smart


class ListWithHeadersMixin(ListModelMixin):
    default_filters = {}
    object_list = None
    _max_score = None
    _scores = None
    _highlights = None
    limit = LIST_DEFAULT_LIMIT
    document_model = None

    def head(self, request, **kwargs):  # pylint: disable=unused-argument
        queryset = self.filter_queryset()
        res = Response()
        res['num_found'] = get(self, 'total_count') or queryset.count()
        return res

    def list(self, request, *args, **kwargs):  # pylint:disable=too-many-locals
        query_params = request.query_params.dict()
        is_csv = query_params.get('csv', False)
        search_string = query_params.get('type', None)
        search_term = query_params.get('q', None)
        if is_csv:
            pattern = search_term
            if pattern:
                query_params._mutable = True  # pylint: disable=protected-access
                query_params['q'] = "*" + search_term + "*"

        if is_csv and not search_string:
            return self.get_csv(request)

        if self.only_facets():
            return Response({'facets': {'fields': self.get_facets()}})
        if self.only_search_stats() and search_term:
            return Response(self.get_search_stats(get(self, '_source_versions', []), get(self, '_extra_filters', None)))

        if self.object_list is None:
            self.object_list = self.filter_queryset()

        if is_csv and search_string:
            klass = type(self.object_list[0])
            queryset = klass.objects.filter(id__in=self.get_object_ids())
            return self.get_csv(request, queryset)

        # Skip pagination if compressed results are requested
        compress = self.should_compress()

        sorted_list = self.object_list

        headers = {}
        results = sorted_list
        paginator = None
        if not compress:
            if not self.limit or int(self.limit) == 0 or int(self.limit) > 1000:
                self.limit = LIST_DEFAULT_LIMIT
            paginator = CustomPaginator(
                request=request, queryset=sorted_list, page_size=self.limit, total_count=self.total_count,
                is_sliced=self.should_perform_es_search(), max_score=get(self, '_max_score'),
                search_scores=get(self, '_scores'), highlights=get(self, '_highlights')
            )
            headers = paginator.headers
            results = paginator.current_page_results
        data = self.serialize_list(results, paginator)

        response = Response(data)
        for key, value in headers.items():
            response[key] = value
        if not headers:
            response['num_found'] = len(sorted_list)
        return response

    def serialize_list(self, results, paginator=None):
        result_dict = self.get_serializer(results, many=True).data
        if self.should_include_facets():
            data = {
                'results': result_dict,
                'facets': {'fields': self.get_facets()}
            }
        elif self.should_include_search_stats() and self.should_perform_es_search():
            data = {
                'results': result_dict,
                'search_stats': self.get_search_stats(self._source_versions, self._extra_filters)
            }
        elif hasattr(self.__class__, 'bundle_response'):
            data = self.bundle_response(result_dict, paginator)
        else:
            data = result_dict
        return data

    def should_include_facets(self):
        return self.request.META.get(INCLUDE_FACETS, False) in TRUTHY

    def is_latest_repo_search_header_present(self):
        return self.request.META.get(SEARCH_LATEST_REPO_VERSION, False) in TRUTHY

    def should_include_search_stats(self):
        return self.request.META.get(INCLUDE_SEARCH_STATS, False) in TRUTHY

    def only_facets(self):
        return self.request.query_params.get(FACETS_ONLY, False) in TRUTHY

    def only_search_stats(self):
        return self.request.query_params.get(SEARCH_STATS_ONLY, False) in TRUTHY

    def should_compress(self):
        return self.request.META.get(HTTP_COMPRESS_HEADER, False) in TRUTHY

    def get_object_ids(self):
        self.object_list.limit_iter = False
        return map(lambda o: o.id, self.object_list[0:100])

    def get_csv(self, request, queryset=None):
        filename, url, prepare_new_file, is_member = None, None, True, False

        parent = None  # TODO: fix this for parent (owner)

        if parent:
            prepare_new_file = False
            user = request.query_params.get('user', None)
            is_member = self._is_member(parent, user)

        try:
            path = request.__dict__.get('_request').path
            filename = '_'.join(compact(path.split('/'))).replace('.', '_')
            kwargs = {
                'filename': filename,
            }
        except Exception:  # pylint: disable=broad-except
            kwargs = {}

        if filename and prepare_new_file:
            url = get_csv_from_s3(filename, is_member)

        if not url:
            queryset = queryset or self._get_query_set_from_view(is_member)
            data = self.get_csv_rows(queryset) if hasattr(self, 'get_csv_rows') else queryset.values()
            url = write_csv_to_s3(data, is_member, **kwargs)

        return Response({'url': url}, status=200)

    @staticmethod
    def _is_member(parent, requesting_user):
        if not parent or type(parent).__name__ in ['UserProfile', 'Organization']:
            return False

        owner = parent.owner
        return owner.members.filter(username=requesting_user).exists() if type(owner).__name__ == 'Organization' else \
            requesting_user == parent.created_by

    def _get_query_set_from_view(self, is_member):
        return self.get_queryset() if is_member else self.get_queryset()[0:CSV_DEFAULT_LIMIT]


class PathWalkerMixin:
    """
    A Mixin with methods that help resolve a resource path to a resource object
    """
    path_info = None

    @staticmethod
    def get_parent_in_path(path_info, levels=1):
        last_index = len(path_info) - 1
        last_slash = path_info.rindex('/')
        if last_slash == last_index:
            last_slash = path_info.rindex('/', 0, last_index)
        path_info = path_info[0:last_slash+1]
        if levels > 1:
            i = 1
            while i < levels:
                last_index = len(path_info) - 1
                last_slash = path_info.rindex('/', 0, last_index)
                path_info = path_info[0:last_slash+1]
                i += 1
        return path_info

    @staticmethod
    def get_object_for_path(path_info, request):
        callback, _, callback_kwargs = resolve(path_info)
        view = callback.cls(request=request, kwargs=callback_kwargs)
        view.initialize(request, path_info, **callback_kwargs)
        return view.get_object()


class SubResourceMixin(PathWalkerMixin):
    """
    Base view for a sub-resource.
    Includes a post-initialize step that determines the parent resource,
    and a get_queryset method that applies the appropriate permissions and filtering.
    """
    user = None
    userprofile = None
    user_is_self = False
    parent_path_info = None
    parent_resource = None

    def initialize(self, request, path_info_segment):
        self.user = request.user
        self.userprofile = self.user
        self.parent_resource = self.userprofile
        if self.user_is_self:
            self.userprofile = self.user
            self.parent_resource = self.userprofile
        else:
            levels = self.get_level()
            self.parent_path_info = self.get_parent_in_path(path_info_segment, levels=levels)
            self.parent_resource = None
            if self.parent_path_info and self.parent_path_info != '/':
                self.parent_resource = self.get_object_for_path(self.parent_path_info, request)

    def get_level(self):
        levels = 1 if isinstance(self, (ListModelMixin, CreateModelMixin)) else 2
        return levels


class ConceptDictionaryMixin(SubResourceMixin):
    permission_classes = (HasPrivateAccess,)


class ConceptDictionaryCreateMixin(ConceptDictionaryMixin):
    """
    Concrete view for creating a model instance.
    """
    def post(self, request, **kwargs):
        self.set_parent_resource()
        return self.create(request, **kwargs)

    def set_parent_resource(self):
        from core.orgs.models import Organization
        from core.users.models import UserProfile
        org = self.kwargs.get('org', None)
        user = self.kwargs.get('user', None)
        if not user and self.user_is_self:
            user = self.request.user.username
        parent_resource = None
        if org:
            parent_resource = Organization.objects.filter(mnemonic=org).first()
        if user:
            parent_resource = UserProfile.objects.filter(username=user).first()

        self.kwargs['parent_resource'] = self.parent_resource = parent_resource

    def create(self, request, **kwargs):  # pylint: disable=unused-argument
        if not self.parent_resource:
            return Response(status=status.HTTP_405_METHOD_NOT_ALLOWED)
        permission = HasOwnership()
        if not permission.has_object_permission(request, self, self.parent_resource):
            return Response(status=status.HTTP_403_FORBIDDEN)
        data = request.data.copy()
        supported_locales = data.pop('supported_locales', '')
        if isinstance(supported_locales, str):
            supported_locales = compact(supported_locales.split(','))

        data = {
            'mnemonic': data.get('id'),
            'supported_locales': supported_locales,
            'version': HEAD, **data, **{self.parent_resource.resource_type.lower(): self.parent_resource.id}
        }

        serializer = self.get_serializer(data=data)
        if serializer.is_valid():
            instance = serializer.save(force_insert=True)
            if serializer.is_valid():
                headers = self.get_success_headers(serializer.data)
                serializer = self.get_detail_serializer(instance)
                return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    @staticmethod
    def get_success_headers(data):
        try:
            return {'Location': data['url']}
        except (TypeError, KeyError):
            return {}


class ConceptDictionaryUpdateMixin(ConceptDictionaryMixin):

    """
    Concrete view for updating a model instance.
    """
    def put(self, request, **kwargs):  # pylint: disable=unused-argument
        super().initialize(request, request.path_info)
        return self.update(request)

    def update(self, request):
        if not self.parent_resource:
            return Response(status=status.HTTP_405_METHOD_NOT_ALLOWED)

        self.object = self.get_object()
        save_kwargs = {'force_update': True, 'parent_resource': self.parent_resource}
        success_status_code = status.HTTP_200_OK

        supported_locales = request.data.pop('supported_locales', '')
        if isinstance(supported_locales, str):
            supported_locales = compact(supported_locales.split(','))

        request.data['supported_locales'] = supported_locales
        serializer = self.get_serializer(self.object, data=request.data, partial=True)

        if serializer.is_valid():
            self.object = serializer.save(**save_kwargs)
            if serializer.is_valid():
                self.object.get_checksums(recalculate=True)
                serializer = self.get_detail_serializer(self.object)
                return Response(serializer.data, status=success_status_code)

        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


class SourceContainerMixin:
    def find_repo_by_canonical_url(self, canonical_url):
        repo = self.source_set.filter(canonical_url=canonical_url).first()
        if not repo:
            repo = self.collection_set.filter(canonical_url=canonical_url).first()
        return repo

    @staticmethod
    def get_object_from_namespace(namespace):
        if not namespace or namespace == '/':
            return None

        klass = None
        if '/orgs/' in namespace:
            from core.orgs.models import Organization
            klass = Organization
        elif '/users/' in namespace:
            from core.users.models import UserProfile
            klass = UserProfile
        if klass:
            return klass.objects.filter(uri=namespace).first()

        return None

    @property
    def bookmarks_count(self):
        return self.pins.count()

    @property
    def sources(self):
        return self.source_set.filter(version=HEAD)

    @property
    def collections(self):
        return self.collection_set.filter(version=HEAD)

    @property
    def all_sources_count(self):
        return self.sources.count()

    @property
    def all_collections_count(self):
        return self.collections.count()

    @property
    def public_sources(self):
        return self.sources.exclude(public_access=ACCESS_TYPE_NONE).count()

    @property
    def public_collections(self):
        return self.collections.exclude(public_access=ACCESS_TYPE_NONE).count()

    @property
    def sources_url(self):
        return self.uri + 'sources/'

    @property
    def collections_url(self):
        return self.uri + 'collections/'


class SourceChildMixin(ChecksumModel):
    class Meta:
        abstract = True

    @property
    def is_in_latest_source_version(self):
        version = self._cached_latest_source_version
        return self.sources.filter(version=version.version).exists() if version else False

    @property
    def latest_source_version(self):
        if self.is_in_latest_source_version:
            return self._cached_latest_source_version
        return None

    @cached_property
    def _cached_latest_source_version(self):
        return self.parent.get_latest_released_version()

    @staticmethod
    def is_strictly_equal(instance1, instance2):
        return instance1.get_checksums() == instance2.get_checksums()

    @staticmethod
    def apply_user_criteria(queryset, user):
        queryset = queryset.exclude(
            Q(parent__user_id__isnull=False, public_access=ACCESS_TYPE_NONE) & ~Q(parent__user_id=user.id))
        queryset = queryset.exclude(
            Q(parent__organization_id__isnull=False, public_access=ACCESS_TYPE_NONE) &
            ~Q(parent__organization__members__id=user.id)
        )
        return queryset

    @staticmethod
    def apply_attribute_based_filters(queryset, params):
        is_latest = params.get('is_latest', None) in TRUTHY
        include_retired = params.get(INCLUDE_RETIRED_PARAM, None) in TRUTHY
        updated_since = parse_updated_since_param(params)
        updated_by = params.get(UPDATED_BY_USERNAME_PARAM, None)
        if is_latest:
            queryset = queryset.filter(is_latest_version=True)
        if not include_retired and not params.get('concept', None) and not params.get('mapping', None):
            queryset = queryset.filter(retired=False)
        if updated_since:
            queryset = queryset.filter(updated_at__gte=updated_since)
        if updated_by:
            queryset = queryset.filter(updated_by__username=updated_by)

        return queryset

    @property
    def source_versions(self):
        return self.sources.exclude(version=HEAD).values_list('uri', flat=True)

    @property
    def collection_versions(self):
        return set(self.expansion_set.exclude(
            collection_version__version=HEAD).values_list('collection_version__uri', flat=True))

    @property
    def versions(self):
        return self.__class__.objects.filter(
            versioned_object_id=self.versioned_object_id).exclude(id=F('versioned_object_id'))

    @property
    def is_versioned_object(self):
        return self.id == self.versioned_object_id

    @property
    def version_url(self):
        if self.is_versioned_object:
            return self.get_latest_version().uri
        return self.uri

    @property
    def head(self):
        return self.versioned_object

    @property
    def is_head(self):
        return self.is_versioned_object

    @property
    def owner(self):
        return get(self, 'parent.parent')

    @property
    def owner_name(self):
        return str(self.owner or '')

    @property
    def owner_type(self):
        return get(self.owner, 'resource_type')

    @property
    def owner_url(self):
        return to_owner_uri(self.uri)

    @property
    def parent_resource(self):
        return get(self.parent, 'mnemonic')

    @property
    def parent_url(self):
        return get(self.parent, 'uri')

    def retire(self, user, comment=None):
        if self.versioned_object.retired:
            return {'__all__': self.ALREADY_RETIRED}

        return self.__update_retire(True, comment or self.WAS_RETIRED, user)

    def unretire(self, user, comment=None):
        if not self.versioned_object.retired:
            return {'__all__': self.ALREADY_NOT_RETIRED}

        return self.__update_retire(False, comment or self.WAS_UNRETIRED, user)

    def __update_retire(self, retired, comment, user):
        latest_version = self.get_latest_version() or self.get_last_version()
        new_version = latest_version.clone()
        new_version.retired = retired
        new_version.comment = comment
        return new_version.save_as_new_version(user)

    @classmethod
    def from_uri_queryset(cls, uri):  # soon to be deleted
        queryset = cls.objects.none()
        from core.collections.utils import is_concept
        is_concept_uri = is_concept(uri)

        try:
            kwargs = get(resolve(uri.split('?')[0]), 'kwargs', {})
            query_params = get_query_params_from_url_string(uri)  # parsing query parameters
            kwargs.update(query_params)
            if 'concept' in kwargs:
                kwargs['concept'] = parse.unquote(kwargs['concept'])
            if 'collection' in kwargs and 'version' in kwargs:
                from core.collections.models import Collection
                collection_version = Collection.get_base_queryset(kwargs).first()
                if collection_version:
                    if 'expansion' in kwargs:
                        expansion = collection_version.expansions.filter(mnemonic=kwargs['expansion']).first()
                    else:
                        expansion = collection_version.expansion
                    if expansion:
                        queryset = expansion.concepts if is_concept_uri else expansion.mappings
            else:
                queryset = cls.get_base_queryset(kwargs)
                if queryset.count() > 1 and \
                        ('concept_version' not in kwargs or 'mapping_version' not in kwargs) and \
                        ('version' not in kwargs):
                    queryset = queryset.filter(is_latest_version=True)
        except:  # pylint: disable=bare-except
            pass

        return queryset

    @classmethod
    def get_parent_and_owner_filters_from_uri(cls, uri):
        filters = {}
        if not uri:
            return filters

        try:
            resolved_uri = resolve(uri)
            kwargs = resolved_uri.kwargs
            filters = cls.get_parent_and_owner_filters_from_kwargs(kwargs)
        except Resolver404:
            pass

        return compact_dict_by_values(filters)

    @staticmethod
    def get_parent_and_owner_filters_from_kwargs(kwargs):
        filters = {}

        if not kwargs:
            return filters

        filters['parent__mnemonic'] = kwargs.get('source')
        if 'org' in kwargs:
            filters['parent__organization__mnemonic'] = kwargs.get('org')
        if 'user' in kwargs:
            filters['parent__user__username'] = kwargs.get('user')

        return filters

    @classmethod
    def get_filter_by_container_criterion(  # pylint: disable=too-many-arguments
            cls, container_prefix, parent, org, user, container_version, is_latest_released, latest_released_version,
            parent_attr=None
    ):
        parent_attr = parent_attr or container_prefix
        criteria = cls.get_exact_or_criteria(f'{parent_attr}__mnemonic', parent)

        if user:
            criteria &= Q(**{f'{parent_attr}__user__username': user})
        if org:
            criteria &= Q(**{f'{parent_attr}__organization__mnemonic': org})
        if is_latest_released:
            criteria &= Q(**{f'{container_prefix}__version': get(latest_released_version, 'version')})
        if container_version and not is_latest_released:
            criteria &= Q(**{f'{container_prefix}__version': container_version})

        return criteria

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
        super().save(force_insert, force_update, using, update_fields)

        if self.is_latest_version and self._counted is False:
            if self.__class__.__name__ == 'Concept':
                self.parent.update_concepts_count()
            else:
                self.parent.update_mappings_count()

            self._counted = True
            self.save(update_fields=['_counted'])

    def collection_references_uris(self, collection):
        ids = self.collection_references(collection).values_list('id', flat=True)
        return [f"{collection.uri}references/{_id}/" for _id in ids]

    def collection_references(self, collection):
        return self.references.filter(collection=collection)

    def __update_latest_version(self, index, is_latest_version, parent, remove_parent=False, add_parent=False):  # pylint: disable=too-many-arguments
        self._index = index  # pylint: disable=protected-access
        self.is_latest_version = is_latest_version
        self.save(update_fields=['is_latest_version', '_index'])
        if parent:
            if remove_parent:
                self.sources.remove(parent)
            if add_parent:
                self.sources.add(parent)

    def unmark_latest_version(self, index=True, parent=None):
        parent = parent or self.parent
        self.__update_latest_version(index, False, parent, True, False)

    def mark_latest_version(self, index=True, parent=None):
        parent = parent or self.parent
        self.__update_latest_version(index, True, parent, False, True)

    @staticmethod
    def validate_locales_limit(names, descriptions):
        pass

    def _process_prev_latest_version_hierarchy(self, prev_latest, add_prev_version_children):
        pass

    def _process_latest_version_hierarchy(self, prev_latest, parent_concept_uris=None, create_parent_version=True):
        pass

    def _index_on_new_version_creation(self, prev_latest):
        if self._index:
            if prev_latest:
                prev_latest.index()
            self.index()

    def remove_locales(self):
        pass

    def save_as_new_version(self, user, **kwargs):  # pylint: disable=too-many-branches,too-many-statements
        cls = self.__class__
        create_parent_version = kwargs.pop('create_parent_version', True)
        parent_concept_uris = kwargs.pop('parent_concept_uris', None)
        add_prev_version_children = kwargs.pop('add_prev_version_children', True)
        _hierarchy_processing = kwargs.pop('_hierarchy_processing', False)
        errors = {}
        self.created_by = self.updated_by = user
        self.version = self.version or generate_temp_version()
        parent = self.parent
        persisted = False
        prev_latest = self.versions.exclude(id=self.id).filter(is_latest_version=True).first()
        is_concept = self.__class__.__name__ == 'Concept'
        try:
            with transaction.atomic():
                self.validate_locales_limit(get(self, 'cloned_names'), get(self, 'cloned_descriptions'))
                cls.pause_indexing()
                self.is_latest_version = True
                self.save(**kwargs)

                if self.id:
                    self.post_version_create(parent, parent_concept_uris)
                    if not prev_latest or _hierarchy_processing:
                        self.set_checksums()
                    should_process_hierarchy = bool(parent_concept_uris)
                    if prev_latest:
                        if not _hierarchy_processing:
                            if is_concept:
                                self._unsaved_child_concept_uris = prev_latest.child_concept_urls
                            self.set_checksums()
                        if Toggle.get(
                                'PREVENT_DUPLICATE_VERSION_TOGGLE'
                        ) and Toggle.get(
                            'CHECKSUMS_TOGGLE'
                        ) and not _hierarchy_processing and self.checksums.get(
                            'standard'
                        ) == prev_latest.get_checksums(recalculate=True).get('standard'):
                            raise ValidationError({'__all__': [SAME_STANDARD_CHECKSUM_ERROR]})
                        if not self._index:
                            self.prev_latest_version_id = prev_latest.id
                        prev_latest.unmark_latest_version(self._index, parent)
                        should_process_hierarchy = should_process_hierarchy or bool(
                            is_concept and prev_latest.parent_concept_urls)
                        if should_process_hierarchy:
                            self._process_prev_latest_version_hierarchy(prev_latest, add_prev_version_children)
                    if should_process_hierarchy:
                        self._process_latest_version_hierarchy(prev_latest, parent_concept_uris, create_parent_version)
                    persisted = True
                    cls.resume_indexing()

                transaction.on_commit(lambda: self._index_on_new_version_creation(prev_latest))
        except ValidationError as err:
            errors.update(err.message_dict)
        finally:
            cls.resume_indexing()
            if not persisted:
                if prev_latest:
                    prev_latest.mark_latest_version(True, parent)
                if self.id:
                    self.remove_locales()
                    self.delete()
                if not errors:
                    errors['non_field_errors'] = [PERSIST_CLONE_ERROR]

        return errors


class ConceptContainerExportMixin:
    permission_classes = (CanViewConceptDictionaryVersion, )

    def get_object(self):
        queryset = self.get_queryset()
        if 'version' not in self.kwargs:
            queryset = queryset.filter(is_latest_version=True)

        instance = queryset.first()

        if not instance:
            raise Http404()

        self.check_object_permissions(self.request, instance)

        return instance

    def get(self, request, *args, **kwargs):  # pylint: disable=unused-argument
        version = self.get_object()
        logger.debug(
            'Export requested for %s version %s', self.entity.lower(), version.version
        )
        if version.is_head and not request.user.is_staff:
            return Response(status=status.HTTP_405_METHOD_NOT_ALLOWED)

        if version.is_exporting:
            return Response(status=status.HTTP_208_ALREADY_REPORTED)

        if version.has_export():
            export_url = version.get_export_url()

            no_redirect = request.query_params.get('noRedirect', False) in TRUTHY
            if no_redirect:
                return Response({'url': export_url}, status=status.HTTP_200_OK)

            response = Response(status=status.HTTP_303_SEE_OTHER)
            response['Location'] = export_url

            # Set headers to ensure sure response is not cached by a client
            response['Cache-Control'] = 'no-cache, no-store, must-revalidate'
            response['Pragma'] = 'no-cache'
            response['Expires'] = '0'
            response['Last-Updated'] = version.get_last_child_update_from_export_url(export_url)
            response['Last-Updated-Timezone'] = settings.TIME_ZONE_PLACE
            return response

        return Response(status=status.HTTP_204_NO_CONTENT)

    def post(self, request, *args, **kwargs):  # pylint: disable=unused-argument
        version = self.get_object()

        if version.is_head and not request.user.is_staff:
            return Response(status=status.HTTP_405_METHOD_NOT_ALLOWED)

        logger.debug('%s Export requested for version %s (post)', self.entity, version.version)

        if version.is_exporting:
            return Response(status=status.HTTP_208_ALREADY_REPORTED)

        force_export = request.query_params.get('force', False) in TRUTHY

        if force_export or not version.has_export():
            status_code = self.handle_export_version()
            return Response(status=status_code)

        no_redirect = request.query_params.get('noRedirect', False) in TRUTHY
        if no_redirect:
            return Response(status=status.HTTP_204_NO_CONTENT)

        response = Response(status=status.HTTP_303_SEE_OTHER)
        response['URL'] = version.uri + 'export/'
        return response

    def delete(self, request, *args, **kwargs):  # pylint: disable=unused-argument
        user = request.user
        version = self.get_object()

        if version.is_head and not user.is_staff:
            return Response(status=status.HTTP_405_METHOD_NOT_ALLOWED)

        permitted = user.is_staff or user.is_superuser or user.is_admin_for(version)

        if not permitted:
            return HttpResponseForbidden()

        if version.has_export():
            get_export_service().remove(version.version_export_path)
            return Response(status=status.HTTP_204_NO_CONTENT)

        return Response(status=status.HTTP_404_NOT_FOUND)


class ConceptContainerProcessingMixin:
    def get_permissions(self):
        if self.request.method == 'POST':
            return [HasOwnership(), ]

        return [CanViewConceptDictionary(), ]

    def get_object(self, queryset=None):  # pylint: disable=unused-argument
        return get_object_or_404(self.get_queryset())

    def get(self, request, *args, **kwargs):  # pylint: disable=unused-argument
        version = self.get_object()
        is_debug = request.query_params.get('debug', None) in TRUTHY

        if is_debug:
            return Response({'is_processing': version.is_processing, 'process_ids': version._background_process_ids})  # pylint: disable=protected-access

        logger.debug('Processing flag requested for %s version %s', self.resource, version)

        response = Response(status=200)
        response.content = version.is_processing
        return response

    def post(self, request, *args, **kwargs):  # pylint: disable=unused-argument
        version = self.get_object()
        logger.debug('Processing flag clearance requested for %s version %s', self.resource, version)

        version.clear_processing()

        return Response(status=status.HTTP_200_OK)