models.py

import time

from django.conf import settings
from django.contrib.postgres.fields import ArrayField
from django.core.exceptions import ValidationError
from django.db import models, transaction
from django.db.models import UniqueConstraint, F
from django.utils import timezone
from django.utils.functional import cached_property
from pydash import get, compact

from core.collections.constants import (
    COLLECTION_TYPE, REFERENCE_ALREADY_EXISTS, CONCEPT_FULLY_SPECIFIED_NAME_UNIQUE_PER_COLLECTION_AND_LOCALE,
    CONCEPT_PREFERRED_NAME_UNIQUE_PER_COLLECTION_AND_LOCALE, COLLECTION_VERSION_TYPE,
    REFERENCE_TYPE_CHOICES, CONCEPT_REFERENCE_TYPE, MAPPING_REFERENCE_TYPE, SOURCE_MAPPINGS, SOURCE_TO_CONCEPTS,
    TRANSFORM_TO_RESOURCE_VERSIONS)
from core.collections.parsers import CollectionReferenceParser
from core.collections.utils import is_concept, is_mapping
from core.common.constants import (
    DEFAULT_REPOSITORY_TYPE, ACCESS_TYPE_VIEW, ACCESS_TYPE_EDIT,
    ES_REQUEST_TIMEOUT, ES_REQUEST_TIMEOUT_ASYNC)
from core.common.models import ConceptContainerModel, BaseResourceModel
from core.common.tasks import seed_children_to_expansion, batch_index_resources, index_expansion_concepts, \
    index_expansion_mappings
from core.common.utils import drop_version, to_owner_uri, generate_temp_version, es_id_in, \
    es_wildcard_search, get_resource_class_from_resource_name, get_exact_search_fields, to_snake_case, es_exact_search
from core.concepts.constants import LOCALES_FULLY_SPECIFIED
from core.concepts.models import Concept
from core.mappings.models import Mapping


class Collection(ConceptContainerModel):
    OBJECT_TYPE = COLLECTION_TYPE
    OBJECT_VERSION_TYPE = COLLECTION_VERSION_TYPE
    es_fields = {
        'collection_type': {'sortable': True, 'filterable': True, 'facet': True, 'exact': True},
        'mnemonic': {'sortable': True, 'filterable': True, 'exact': True},
        'name': {'sortable': True, 'filterable': True, 'exact': True},
        'last_update': {'sortable': True, 'filterable': False, 'default': 'desc'},
        'locale': {'sortable': False, 'filterable': True, 'facet': True},
        'owner': {'sortable': True, 'filterable': True, 'facet': True, 'exact': True},
        'owner_type': {'sortable': False, 'filterable': True, 'facet': True},
        'custom_validation_schema': {'sortable': False, 'filterable': True, 'facet': True},
        'canonical_url': {'sortable': True, 'filterable': True},
        'experimental': {'sortable': False, 'filterable': False, 'facet': False},
        'external_id': {'sortable': False, 'filterable': True, 'facet': False, 'exact': False},
    }

    class Meta:
        db_table = 'collections'
        constraints = [
            UniqueConstraint(
                fields=['mnemonic', 'version', 'organization'],
                name="org_collection_unique",
                condition=models.Q(user=None),
            ),
            UniqueConstraint(
                fields=['mnemonic', 'version', 'user'],
                name="user_collection_unique",
                condition=models.Q(organization=None),
            )
        ]
        indexes = [] + ConceptContainerModel.Meta.indexes

    collection_type = models.TextField(blank=True)
    preferred_source = models.TextField(blank=True)
    repository_type = models.TextField(default=DEFAULT_REPOSITORY_TYPE, blank=True)
    custom_resources_linked_source = models.TextField(blank=True)
    immutable = models.BooleanField(null=True, blank=True, default=None)
    locked_date = models.DateTimeField(null=True, blank=True)
    autoexpand_head = models.BooleanField(default=True, null=True)
    autoexpand = models.BooleanField(default=True, null=True)
    expansion_uri = models.TextField(null=True, blank=True)

    def set_active_concepts(self):
        if self.expansion_uri:
            self.active_concepts = self.expansion.concepts.filter(retired=False, is_active=True).count()

    def set_active_mappings(self):
        if self.expansion_uri:
            self.active_mappings = self.expansion.mappings.filter(retired=False, is_active=True).count()

    @staticmethod
    def get_search_document():
        from core.collections.documents import CollectionDocument
        return CollectionDocument

    @classmethod
    def get_base_queryset(cls, params):
        collection = params.pop('collection', None)
        contains_uri = params.pop('contains', None)
        include_references = params.pop('include_references', None) in [True, 'true']
        queryset = super().get_base_queryset(params)
        if collection:
            queryset = queryset.filter(cls.get_exact_or_criteria('mnemonic', collection))
        if contains_uri:
            queryset = queryset.filter(
                references__expression=contains_uri, public_access__in=[ACCESS_TYPE_EDIT, ACCESS_TYPE_VIEW]
            )
        if include_references:
            queryset = queryset.prefetch_related('references')

        return queryset

    @property
    def collection(self):
        return self.mnemonic

    @staticmethod
    def get_resource_url_kwarg():
        return 'collection'

    def update_version_data(self, head):
        super().update_version_data(head)
        self.collection_type = head.collection_type
        self.preferred_source = head.preferred_source
        self.repository_type = head.repository_type
        self.custom_resources_linked_source = head.custom_resources_linked_source
        self.immutable = head.immutable
        self.locked_date = head.locked_date

    @property
    def should_auto_expand(self):
        if self.is_head:
            return self.autoexpand_head

        return self.autoexpand

    def validate(self, reference):
        if self.should_auto_expand:
            reference.full_clean()
        else:
            reference.last_resolved_at = None
        if reference.expression and self.references.filter(expression=reference.expression).exists():
            raise ValidationError({reference.expression: [REFERENCE_ALREADY_EXISTS]})

        if self.is_openmrs_schema and self.expansion_uri:
            if reference._concepts is None or reference._concepts.count() == 0:  # pylint: disable=protected-access
                return
            for concept in reference._concepts:   # pylint: disable=protected-access
                self.check_concept_uniqueness_in_collection_and_locale_by_name_attribute(
                    concept, attribute='type__in', value=LOCALES_FULLY_SPECIFIED,
                    error_message=CONCEPT_FULLY_SPECIFIED_NAME_UNIQUE_PER_COLLECTION_AND_LOCALE
                )
                self.check_concept_uniqueness_in_collection_and_locale_by_name_attribute(
                    concept, attribute='locale_preferred', value=True,
                    error_message=CONCEPT_PREFERRED_NAME_UNIQUE_PER_COLLECTION_AND_LOCALE
                )

    def check_concept_uniqueness_in_collection_and_locale_by_name_attribute(
            self, concept, attribute, value, error_message
    ):
        other_concepts_in_collection = self.expansion.concepts
        if not other_concepts_in_collection.exists():
            return

        matching_names_in_concept = {}
        names = concept.names.filter(**{attribute: value})

        for name in names:
            validation_error = dict(names=[error_message])
            # making sure names in the submitted concept meet the same rule
            name_key = name.locale + name.name
            if name_key in matching_names_in_concept:
                raise ValidationError(validation_error)

            matching_names_in_concept[name_key] = True
            if other_concepts_in_collection.filter(
                    names__name=name.name, names__locale=name.locale, **{f"names__{attribute}": value}
            ).exists():
                raise ValidationError(validation_error)

    @transaction.atomic
    def add_expressions(
            self, data, user, cascade=False, transform=False):
        parser = CollectionReferenceParser(data, transform, cascade, user)
        parser.parse()
        parser.to_reference_structure()
        references = parser.to_objects()

        return self.add_references(references, user)

    def add_references(self, references, user=None):
        errors = {}
        added_references = []
        for reference in references:
            reference.expression = reference.build_expression()
            reference.collection = self
            reference.created_by = user
            try:
                self.validate(reference)
                reference.save()
            except Exception as ex:
                errors[reference.expression] = ex.messages if hasattr(ex, 'messages') else ex
                continue
            if reference.id:
                added_references.append(reference)

        if self.expansion_uri:
            self.expansion.add_references(added_references)
        if user and user.is_authenticated:
            self.updated_by = user
        self.save()
        self.update_children_counts()
        return added_references, errors

    def seed_references(self):
        head = self.head
        if head:
            for reference in head.references.all():
                new_reference = reference.clone(last_resolved_at=timezone.now(), collection=self)
                new_reference.save()
                new_reference.concepts.set(reference.concepts.all())
                new_reference.mappings.set(reference.mappings.all())

    @staticmethod
    def is_validation_necessary():
        return False

    @property
    def expansions_count(self):
        return self.expansions.count()

    def delete_references(self, expressions):
        if expressions == '*':
            references_to_be_deleted = self.references
            if self.expansion_uri:
                self.expansion.delete_expressions(expressions)
        else:
            references_to_be_deleted = self.references.filter(expression__in=expressions)
            if self.expansion_uri:
                self.expansion.delete_references(references_to_be_deleted)

        references_to_be_deleted.all().delete()

    def get_cascaded_mapping_uris_from_concept_expressions(self, expressions):
        mapping_uris = []

        if not self.expansion_uri:
            return mapping_uris

        for expression in expressions:
            if is_concept(expression):
                mapping_uris += list(
                    self.expansion.mappings.filter(
                        from_concept__uri__icontains=drop_version(expression)).values_list('uri', flat=True)
                )

        return mapping_uris

    def cascade_children_to_expansion(self, expansion_data=None, index=True, sync=False):  # pylint: disable=arguments-differ
        if not expansion_data:
            expansion_data = {}
        should_auto_expand = self.should_auto_expand

        if should_auto_expand and not self.expansions.exists() and not get(expansion_data, 'mnemonic'):
            expansion_data['mnemonic'] = Expansion.get_auto_expand_mnemonic(self.version)
            expansion_data['is_processing'] = True
        expansion = Expansion.persist(index=index, **expansion_data, collection_version=self, sync=sync)

        if should_auto_expand and not self.expansion_uri:
            self.expansion_uri = expansion.uri
            self.save()

        return expansion

    def index_children(self):
        if self.expansion_uri:
            from core.concepts.documents import ConceptDocument
            from core.mappings.documents import MappingDocument

            self.batch_index(self.expansion.concepts, ConceptDocument)
            self.batch_index(self.expansion.mappings, MappingDocument)

    @property
    def expansion(self):
        if self.expansion_uri:
            return self.expansions.filter(uri=self.expansion_uri).first()

        return None

    @property
    def active_references(self):
        return self.references.count()

    @property
    def last_concept_update(self):
        updated_at = None
        if self.expansion_uri and self.expansion.concepts.exists():
            updated_at = self.expansion.concepts.latest('updated_at').updated_at
        return updated_at

    @property
    def last_mapping_update(self):
        updated_at = None
        if self.expansion_uri and self.expansion.mappings.exists():
            updated_at = self.expansion.mappings.latest('updated_at').updated_at
        return updated_at

    @property
    def expansions_url(self):
        return self.uri + 'expansions/'


class ReferencedConcept(models.Model):
    reference = models.ForeignKey('collections.CollectionReference', on_delete=models.CASCADE)
    concept = models.ForeignKey('concepts.Concept', on_delete=models.CASCADE)


class ReferencedMapping(models.Model):
    reference = models.ForeignKey('collections.CollectionReference', on_delete=models.CASCADE)
    mapping = models.ForeignKey('mappings.Mapping', on_delete=models.CASCADE)


class CollectionReference(models.Model):
    class Meta:
        db_table = 'collection_references'

    OPERATOR_EQUAL = '='
    OPERATOR_IN = 'in'
    ALLOWED_FILTER_OPS = [OPERATOR_EQUAL, OPERATOR_IN]

    _concepts = None
    _mappings = None
    original_expression = None

    # core
    id = models.BigAutoField(primary_key=True)
    expression = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    last_resolved_at = models.DateTimeField(default=timezone.now, null=True)
    reference_type = models.CharField(choices=REFERENCE_TYPE_CHOICES, default=CONCEPT_REFERENCE_TYPE, max_length=10)
    created_by = models.ForeignKey('users.UserProfile', null=True, blank=True, on_delete=models.SET_NULL)

    # FHIR specs
    filter = models.JSONField(null=True, blank=True)
    display = models.TextField(null=True, blank=True)
    namespace = models.TextField(null=True, blank=True)
    code = models.CharField(null=True, blank=True, max_length=255)
    system = models.TextField(null=True, blank=True)
    version = models.CharField(null=True, blank=True, max_length=255)
    valueset = ArrayField(models.TextField(), null=True, blank=True)
    cascade = models.JSONField(null=True, blank=True)
    transform = models.CharField(null=True, blank=True, max_length=255)

    resource_version = models.CharField(null=True, blank=True, max_length=255)

    # associations
    concepts = models.ManyToManyField('concepts.Concept', related_name='references', through=ReferencedConcept)
    mappings = models.ManyToManyField('mappings.Mapping', related_name='references', through=ReferencedMapping)
    collection = models.ForeignKey('collections.Collection', related_name='references', on_delete=models.CASCADE)

    def clone(self, **kwargs):
        return CollectionReference(
            expression=self.expression,
            reference_type=self.reference_type,
            filter=self.filter,
            display=self.display,
            namespace=self.namespace,
            code=self.code,
            system=self.system,
            version=self.version,
            valueset=self.valueset,
            cascade=self.cascade,
            transform=self.transform,
            resource_version=self.resource_version,
            **kwargs,
        )

    def build_expression(self):
        if self.expression:
            return self.expression

        expression = ''
        if self.system:
            is_canonical = self.system.startswith('http://') or self.system.startswith('https://')
            expression = self.system
            if self.version:
                expression += '|' + self.version if is_canonical else self.version
        elif self.valueset and isinstance(self.valueset, list):
            expression = self.valueset[0]  # pylint: disable=unsubscriptable-object

        is_canonical = expression.startswith('https://') or expression.startswith('http://')
        if self.code or self.filter or not is_canonical:
            if self.is_concept:
                expression += 'concepts/' if expression.endswith('/') else '/concepts/'
            elif self.is_mapping:
                expression += 'mappings/' if expression.endswith('/') else '/mappings/'

            if expression:
                if self.code:
                    expression += self.code + '/'
                    if self.resource_version:
                        expression += self.resource_version + '/'
                elif self.filter:
                    expression += '?' + self.filter_to_querystring()
        return expression

    @cached_property
    def uri(self):
        return self.calculate_uri(self.collection)

    def calculate_uri(self, collection):
        if collection:
            return f'{collection.uri}references/{self.id}/'
        return None

    @property
    def without_version(self):
        return drop_version(self.expression)

    def fetch_concepts(self, refetch=False):
        if not get(self, '_fetched') or refetch:
            self._concepts, self._mappings = self.get_concepts()
            self._fetched = True

    def fetch_mappings(self, refetch=False):
        if not get(self, '_fetched') or refetch:
            self._mappings = self.get_mappings()
            self._fetched = True

    def get_concepts(self):
        queryset = self.get_resource_queryset_from_system_and_valueset(Concept, 'concepts')
        mapping_queryset = Mapping.objects.none()

        if self.code:
            queryset = queryset.filter(mnemonic=self.code)
            if self.resource_version:
                queryset = queryset.filter(version=self.resource_version)
        if self.cascade:
            cascade_params = self.get_concept_cascade_params()
            for concept in queryset:
                result = concept.cascade(**cascade_params)
                queryset |= result['concepts']
                mapping_queryset |= result['mappings']

        if self.should_apply_filter():
            queryset = self.apply_filters(queryset, Concept)

        if self.should_transform_to_latest_version():
            queryset = self.transform_to_latest_version(queryset, Concept)
            if self.code:
                concept = queryset.first()
                self.resource_version = concept.version
                self.expression = concept.uri
            if mapping_queryset.exists():
                mapping_queryset = self.transform_to_latest_version(mapping_queryset, Mapping)
        return queryset, mapping_queryset

    def get_mappings(self):
        queryset = self.get_resource_queryset_from_system_and_valueset(Mapping, 'mappings')

        if self.code:
            queryset = queryset.filter(mnemonic=self.code)
            if self.resource_version:
                queryset = queryset.filter(version=self.resource_version)

        if self.should_apply_filter():
            queryset = self.apply_filters(queryset, Mapping)

        if self.should_transform_to_latest_version():
            queryset = self.transform_to_latest_version(queryset, Mapping)
            if self.code:
                mapping = queryset.first()
                self.resource_version = mapping.version
                self.expression = mapping.uri
        return queryset

    @staticmethod
    def transform_to_latest_version(queryset, klass):
        ids = []
        resources = klass.objects.filter(id__in=queryset.values_list('id', flat=True))
        for resource in resources.filter(id=F('versioned_object_id')):
            ids.append(resource.get_latest_version().id)
        if ids:
            queryset = resources.exclude(id=F('versioned_object_id')) | klass.objects.filter(id__in=ids)

        return queryset

    def should_transform_to_latest_version(self):
        return not self.resource_version and self.transform

    def should_apply_filter(self):
        return not self.code and self.filter

    def get_concept_cascade_params(self):
        if isinstance(self.cascade, dict) and self.cascade and 'method' in self.cascade:
            method = self.cascade.pop('method')
        else:
            method = self.cascade

        cascade_params = {
            'source_mappings': method == SOURCE_MAPPINGS,
            'source_to_concepts': method == SOURCE_TO_CONCEPTS,
            'cascade_levels': 1 if self.cascade == method else get(self.cascade, 'level', '*')
        }
        if isinstance(self.cascade, dict):
            cascade_params = {**cascade_params, **self.cascade}
        return cascade_params

    def __is_exact_search_filter(self):
        return bool(next(
            (filter_def for filter_def in self.filter if  # pylint:disable=not-an-iterable
             filter_def['property'] == 'exact_match' and filter_def['value'] == 'on'),
            False
        ))

    def apply_filters(self, queryset, resource_klass):
        if self.filter:
            document = resource_klass.get_search_document()
            search = document.search()
            search = es_id_in(search, queryset.values_list('id', flat=True))
            is_exact_search = self.__is_exact_search_filter()
            for filter_def in self.filter:  # pylint: disable=not-an-iterable
                if to_snake_case(filter_def['property']) == 'exact_match':
                    continue
                val = filter_def['value']
                exact_search_fields = get_exact_search_fields(
                    resource_klass) if filter_def['property'] == 'q' else [to_snake_case(filter_def['property'])]
                if is_exact_search:
                    search = es_exact_search(search, val, exact_search_fields)
                else:
                    search = es_wildcard_search(
                        search, val, exact_search_fields, name_attr='_name' if self.is_concept else 'name'
                    )
            queryset = search.params(request_timeout=ES_REQUEST_TIMEOUT_ASYNC).to_queryset()
        return queryset

    # returns intersection of system and valueset resources considering creator permissions
    def get_resource_queryset_from_system_and_valueset(self, resource_klass, resource_relation):
        system_version = self.resolve_system_version()
        valueset_versions = self.resolve_valueset_versions()
        queryset = resource_klass.objects.none()
        if system_version and system_version.can_view_all_content(self.created_by):
            queryset = get(system_version, resource_relation).filter()
            if system_version.is_head and not self.resource_version:
                queryset = queryset.filter(
                    is_latest_version=True
                ) if self.transform else queryset.filter(id=F('versioned_object_id'))

        if valueset_versions:
            for valueset in valueset_versions:
                if valueset.expansion_uri and valueset.can_view_all_content(self.created_by):
                    rel = get(valueset.expansion, resource_relation)
                    queryset &= rel.all()
        if not system_version and not valueset_versions and self.expression:
            queryset = resource_klass.from_uri_queryset(self.expression)

        return queryset

    def resolve_system_version(self):
        if self.system:
            version = Collection.resolve_reference_expression(self.system, self.namespace, self.version)
            if version.id:
                return version
        return None

    def resolve_valueset_versions(self):
        versions = []
        if isinstance(self.valueset, list):
            for valueset in self.valueset:  # pylint: disable=not-an-iterable
                if valueset:
                    version = Collection.resolve_reference_expression(valueset, self.namespace)
                    if version.id:
                        versions.append(version)
        return versions

    def clean(self):
        if not self.is_valid_filter():
            raise ValidationError(dict(filter=['Invalid filter schema.']))

        self.original_expression = str(self.expression)
        if self.transform and self.transform.lower() != TRANSFORM_TO_RESOURCE_VERSIONS:
            self.transform = None

        self.evaluate()
        is_resolved = bool((self._mappings and self._mappings.exists()) or (self._concepts and self._concepts.exists()))
        if not is_resolved:
            self.last_resolved_at = None
        if not self.reference_type:
            self.reference_type = MAPPING_REFERENCE_TYPE if self.is_mapping else CONCEPT_REFERENCE_TYPE

        if self.expression is None:
            self.expression = self.build_expression()

    def filter_to_querystring(self):
        if self.filter:
            queries = []
            for filter_def in self.filter:  # pylint: disable=not-an-iterable
                value = ','.join(filter_def['value']) if isinstance(filter_def['value'], list) else filter_def['value']
                queries.append(f'{filter_def["property"]}={value}')
            return '&'.join(queries)
        return None

    @cached_property
    def expression_with_filters(self):
        querystring = self.filter_to_querystring()
        if querystring:
            joiner = '&' if '?' in self.expression else '&'
            return f"{self.expression}{joiner}{querystring}"
        return self.expression

    def is_valid_filter(self):
        if not self.filter:
            return True

        if not isinstance(self.filter, list):
            return False
        if len(self.filter) != len(compact(self.filter)):
            return False

        return all(map(self.__is_valid_filter_schema, self.filter))

    def get_allowed_filter_properties(self):
        common = ['q', 'exact_match']
        if self.is_concept:
            return [*Concept.es_fields.keys(), *common]
        if self.is_mapping:
            return [*Mapping.es_fields.keys(), *common]
        return common

    def __is_valid_filter_schema(self, filter_def):
        return isinstance(filter_def, dict) and \
               sorted(filter_def.keys()) == sorted(['property', 'op', 'value']) and \
               {type(val) for val in filter_def.values()} == {str} and \
               filter_def['op'] in self.ALLOWED_FILTER_OPS and \
               to_snake_case(filter_def['property']) in self.get_allowed_filter_properties()

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

        if self.id and get(self, '_fetched'):
            if self._concepts is not None and self._concepts.exists():
                self.concepts.set(self._concepts)
            if self._mappings is not None and self._mappings.exists():
                self.mappings.set(self._mappings)

    @property
    def is_concept(self):
        return self.reference_type == 'concepts' or is_concept(self.expression)

    @property
    def is_mapping(self):
        return self.reference_type == 'mappings' or is_mapping(self.expression)

    def evaluate(self):
        if self.is_concept:
            self.fetch_concepts()
        elif self.is_mapping:
            self.fetch_mappings()

        self._fetched = True

    def get_related_uris(self):
        self.fetch_concepts()
        return [*set(self._concepts.values_list('uri', flat=True)), *set(self._mappings.values_list('uri', flat=True))]


def default_expansion_parameters():
    return {
        "filter": "",
        "date": "",
        "count": 0,
        "offset": 0,
        "includeDesignations": True,
        "activeOnly": False,
        "includeDefinition": False,
        "excludeNested": True,
        "excludeNotForUI": True,
        "excludePostCoordinated": True,
        "exclude-system": "",
        "system-version": "",
        "check-system-version": "",
        "force-system-version": ""
    }


class Expansion(BaseResourceModel):
    class Meta:
        db_table = 'collection_expansions'
        indexes = [] + BaseResourceModel.Meta.indexes

    parameters = models.JSONField(default=default_expansion_parameters)
    canonical_url = models.URLField(null=True, blank=True)
    text = models.TextField(null=True, blank=True)
    concepts = models.ManyToManyField('concepts.Concept', blank=True, related_name='expansion_set')
    mappings = models.ManyToManyField('mappings.Mapping', blank=True, related_name='expansion_set')
    collection_version = models.ForeignKey(
        'collections.Collection', related_name='expansions', on_delete=models.CASCADE)
    is_processing = models.BooleanField(default=False)

    @property
    def is_auto_generated(self):
        return self.mnemonic == self.auto_generated_mnemonic

    @property
    def auto_generated_mnemonic(self):
        return self.get_auto_expand_mnemonic(get(self, 'collection_version.version'))

    @staticmethod
    def get_auto_expand_mnemonic(version):
        return f"autoexpand-{version}"

    @staticmethod
    def get_resource_url_kwarg():
        return 'expansion'

    @staticmethod
    def get_url_kwarg():
        return 'expansion'

    @property
    def is_default(self):
        return self.uri == self.collection_version.expansion_uri

    @property
    def expansion(self):
        return self.mnemonic

    @property
    def active_concepts(self):
        return self.concepts.count()

    @property
    def active_mappings(self):
        return self.mappings.count()

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

    def apply_parameters(self, queryset, is_concept_queryset):
        parameters = ExpansionParameters(self.parameters, is_concept_queryset)
        return parameters.apply(queryset)

    def index_concepts(self):
        if self.concepts.exists():
            if get(settings, 'TEST_MODE', False):
                index_expansion_concepts(self.id)
            else:
                index_expansion_concepts.apply_async((self.id, ), queue='indexing')

    def index_mappings(self):
        if self.mappings.exists():
            if get(settings, 'TEST_MODE', False):
                index_expansion_mappings(self.id)
            else:
                index_expansion_mappings.apply_async((self.id, ), queue='indexing')

    @staticmethod
    def to_ref_list(references):
        if isinstance(references, CollectionReference):
            return [references]
        if isinstance(references, list):
            return references
        return references.all()

    def delete_references(self, references):
        refs = self.to_ref_list(references)

        index_concepts = False
        index_mappings = False
        for reference in refs:
            if reference.is_concept:
                concepts = reference.concepts
                if concepts.exists():
                    index_concepts = True
                    self.concepts.set(self.concepts.exclude(id__in=concepts.values_list('id', flat=True)))
            elif reference.is_mapping:
                mappings = reference.mappings
                if mappings.exists():
                    index_mappings = True
                    self.mappings.set(self.mappings.exclude(id__in=mappings.values_list('id', flat=True)))
        if index_concepts:
            self.index_concepts()
        if index_mappings:
            self.index_mappings()

    def delete_expressions(self, expressions):
        concepts_filters = None
        mappings_filters = None
        if expressions == '*':
            if self.concepts.exists():
                concepts_filters = dict(id__in=list(self.concepts.values_list('id', flat=True)))
                self.concepts.clear()
            if self.mappings.exists():
                mappings_filters = dict(id__in=list(self.mappings.values_list('id', flat=True)))
                self.mappings.clear()
        else:
            concepts_filters = dict(uri__in=expressions)
            mappings_filters = dict(uri__in=expressions)
            self.concepts.set(self.concepts.exclude(**concepts_filters))
            self.mappings.set(self.mappings.exclude(**mappings_filters))

        if not get(settings, 'TEST_MODE', False):
            batch_index_resources.apply_async(('concept', concepts_filters), queue='indexing')
            batch_index_resources.apply_async(('mapping', mappings_filters), queue='indexing')

    def add_references(self, references, index=True):
        refs = self.to_ref_list(references)

        index_concepts = False
        index_mappings = False
        mappings = Mapping.objects.none()
        is_auto_generated = self.is_auto_generated
        for reference in refs:
            if reference.is_concept:
                if is_auto_generated:
                    concepts = reference.concepts
                else:
                    concepts, mappings = reference.get_concepts()
                if concepts.exists():
                    self.concepts.add(*self.apply_parameters(concepts, True))
                    index_concepts = True
                if mappings.exists():
                    self.mappings.add(*self.apply_parameters(mappings, False))
                    index_mappings = True
            elif reference.is_mapping:
                mappings = reference.mappings if is_auto_generated else reference.get_mappings()
                if mappings.exists():
                    self.mappings.add(*self.apply_parameters(mappings, False))
                    index_mappings = True

        if index:
            if index_concepts:
                self.index_concepts()
            if index_mappings:
                self.index_mappings()

    def seed_children(self, index=True):
        return self.add_references(self.collection_version.references, index)

    def wait_until_processed(self):  # pragma: no cover
        processing = self.is_processing
        while processing:
            print("Expansion is still processing, sleeping for 5 secs...")
            time.sleep(5)
            self.refresh_from_db()
            processing = self.is_processing
            if not processing:
                print("Expansion processed, waking up...")

    def calculate_uri(self):
        version = self.collection_version
        if version.is_head:
            return self.collection_version.uri + f'HEAD/expansions/{self.mnemonic}/'
        return self.collection_version.uri + f'expansions/{self.mnemonic}/'

    def clean(self):
        if not self.parameters:
            self.parameters = default_expansion_parameters()

        super().clean()

    @classmethod
    def persist(cls, index, **kwargs):
        sync = kwargs.pop('sync', False)
        expansion = cls(**kwargs)
        temp_version = not bool(expansion.mnemonic)
        if temp_version:
            expansion.mnemonic = generate_temp_version()
        expansion.clean()
        expansion.full_clean()
        expansion.save()
        if temp_version and expansion.id:
            expansion.mnemonic = expansion.id
            expansion.save()

        if get(settings, 'TEST_MODE', False) or sync:
            seed_children_to_expansion(expansion.id, index)
        else:
            seed_children_to_expansion.delay(expansion.id, index)

        return expansion

    def get_mappings_for_concept(self, concept, include_indirect=False):
        concept_criteria = [concept.uri, drop_version(concept.uri)]
        criteria = models.Q(from_concept__uri__in=concept_criteria)
        if include_indirect:
            criteria |= models.Q(to_concept__uri__in=concept_criteria)
        return self.mappings.filter(criteria)


class ExpansionParameters:
    ACTIVE = 'activeOnly'
    TEXT_FILTER = 'filter'
    EXCLUDE_SYSTEM = 'exclude-system'
    INCLUDE_SYSTEM = 'system-version'
    DATE = 'date'

    def __init__(self, parameters, is_concept_queryset=True):
        self.parameters = parameters
        self.parameter_classes = {}
        self.before_filters = {}
        self.is_concept_queryset = is_concept_queryset
        self.to_parameter_classes()

    def to_parameter_classes(self):
        for parameter, value in self.parameters.items():
            parameter = parameter.replace(' ', '')
            if parameter == self.ACTIVE:
                self.parameter_classes[parameter] = ExpansionActiveParameter(value=value)
            elif parameter == self.TEXT_FILTER:
                self.parameter_classes[parameter] = ExpansionTextFilterParameter(value=value)
            elif parameter == self.INCLUDE_SYSTEM:
                self.parameter_classes[parameter] = ExpansionIncludeSystemParameter(value=value)
            elif parameter == self.EXCLUDE_SYSTEM:
                self.parameter_classes[parameter] = ExpansionExcludeSystemParameter(value=value)
            elif parameter == self.DATE:
                self.parameter_classes[parameter] = ExpansionDateParameter(value=value)

    def apply(self, queryset):
        queryset = self.apply_before_filters(queryset)
        queryset = self.apply_after_filters(queryset)
        return queryset

    def apply_before_filters(self, queryset):
        self.make_before_filters()
        return queryset.filter(**self.before_filters)

    def apply_after_filters(self, queryset):
        # order of parameters matters here
        for parameter in [self.INCLUDE_SYSTEM, self.DATE, self.EXCLUDE_SYSTEM, self.TEXT_FILTER]:
            klass = get(self.parameter_classes, parameter)
            if klass and klass.after_filter:
                queryset = klass.apply(queryset, self.is_concept_queryset)
        return queryset

    def make_before_filters(self):
        for _, klass in self.parameter_classes.items():
            if klass.before_filter:
                self.before_filters = {**self.before_filters, **klass.filters}


class ExpansionParameter:
    before_filter = False   # returns db criterion, they can only be applied on DB queries
    after_filter = False   # takes queryset to run custom code or anything after

    def __init__(self, value):
        self.value = value

    def is_valid_string(self):
        return self.value and isinstance(self.value, str)


class ExpansionActiveParameter(ExpansionParameter):
    before_filter = True
    default_filters = dict(is_active=True, retired=False)

    @property
    def filters(self):
        if self.value is True:
            return self.default_filters
        return {}


class ExpansionTextFilterParameter(ExpansionParameter):
    after_filter = True

    def apply(self, queryset, is_concept_queryset):
        if self.is_valid_string():
            klass = get_resource_class_from_resource_name('concept' if is_concept_queryset else 'mapping')
            document = klass.get_search_document()
            search = document.search()
            search = es_id_in(search, queryset.values_list('id', flat=True))
            search = es_wildcard_search(
                search, self.value, get_exact_search_fields(klass),
                name_attr='_name' if is_concept_queryset else 'name'
            )
            queryset = search.params(request_timeout=ES_REQUEST_TIMEOUT).to_queryset()

        return queryset


class ExpansionSystemParameter(ExpansionParameter):
    after_filter = True

    def get_criterion(self):
        criterion = models.Q()
        for system in self.value.split(','):
            canonical_url = system
            version = None
            if '|' in system:
                canonical_url, version = system.split('|')
            filters = dict(canonical_url=canonical_url)
            if version:
                filters['version'] = version
            criterion |= models.Q(**filters)

        return criterion

    def get_code_systems(self):
        from core.sources.models import Source
        return Source.objects.filter(self.get_criterion())

    def get_value_sets(self):
        return Collection.objects.filter(self.get_criterion())

    @staticmethod
    def filter_queryset(queryset, code_systems, value_sets):
        raise NotImplementedError

    def apply(self, queryset, _=None):
        if self.is_valid_string():
            queryset = self.filter_queryset(queryset, self.get_code_systems(), self.get_value_sets())
        return queryset


class ExpansionExcludeSystemParameter(ExpansionSystemParameter):
    @staticmethod
    def filter_queryset(queryset, code_systems, value_sets):
        criteria = models.Q()

        if code_systems.exists():
            criteria |= models.Q(sources__in=code_systems)
        if value_sets.exists():
            criteria |= models.Q(expansion_set__collection_version__in=value_sets)
        return queryset.exclude(criteria)


class ExpansionIncludeSystemParameter(ExpansionSystemParameter):
    @staticmethod
    def filter_queryset(queryset, code_systems, value_sets):
        return queryset.filter(
            models.Q(sources__in=code_systems) |
            models.Q(expansion_set__collection_version__in=value_sets)
        )


class ExpansionDateParameter(ExpansionIncludeSystemParameter):
    @staticmethod
    def get_date_filter(date):
        if date.count('-') >= 3 or date.count(":"):
            return dict(revision_date=date)
        parts = date.split('-')
        filters = dict(revision_date__year=parts[0])
        if len(parts) > 1:
            filters['revision_date__month'] = parts[1]
        if len(parts) > 2:
            filters['revision_date__day'] = parts[2]

        return filters

    def get_criterion(self):
        criterion = models.Q()
        for date in self.value.split(','):
            criterion |= models.Q(**self.get_date_filter(date))

        return criterion