from django.db.models import Prefetch
from rest_framework import routers, serializers, viewsets
from rest_framework.decorators import action
from rest_framework.response import Response

from membershipworks.models import Member
from .models import (
    Department,
    Certification,
    CertificationDefinition,
    CertificationVersion,
)


class DepartmentSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Department
        fields = ["name", "parent", "list_moderator_flag", "list_reply_to_address"]


class DepartmentViewSet(viewsets.ModelViewSet):
    queryset = Department.objects.all()
    serializer_class = DepartmentSerializer

    @action(detail=False, methods=["get"])
    def mailing_lists(self, request, format=None):
        """
        Generate a mailing list for each department, containing all
        certified users for tools in that department or child departments
        """
        departments = self.queryset.filter(has_mailing_list=True).prefetch_related(
            "children",
            "list_moderator_flag",
            Prefetch(
                "certificationdefinition_set__certificationversion_set__certification_set__member",
                queryset=Member.objects.with_is_active(),
            ),
        )
        lists = {}
        for department in departments:
            if department.list_moderator_flag is not None:
                moderator_emails = department.list_moderator_flag.members.values_list(
                    "email", flat=True
                )
            else:
                moderator_emails = []

            # TODO: this could be done in SQL instead if
            #       membershipworks was in the same database
            active_certified_members = {
                member_cert.member.sanitized_mailbox
                for certification in department.certificationdefinition_set.all()
                for version in certification.certificationversion_set.all()
                for member_cert in version.certification_set.all()
                if member_cert.member and member_cert.member.is_active
            }

            lists[department.list_name] = {
                "real_name": department.list_name,
                "moderator": moderator_emails,
                "subject_prefix": f"[CMS {department.name}] ",
                "reply_to_address": department.list_reply_to_address,
                "members": active_certified_members,
            }

        # Add child departments' members to their parents
        # TODO: this seems wildly inefficient
        def recurse_children(department):
            for child in department.children.all():
                recurse_children(child)

                lists[department.list_name]["members"] |= lists[child.list_name][
                    "members"
                ]

        for department in departments:
            if department.parent_id is None:
                recurse_children(department)

        return Response(lists)


class CertificationDefinitionSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = CertificationDefinition
        fields = ["certification_name", "department", "mailing_list"]


class CertificationDefinitionViewSet(viewsets.ModelViewSet):
    queryset = CertificationDefinition.objects.all()
    serializer_class = CertificationDefinitionSerializer


class CertificationVersionSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = CertificationVersion
        fields = ["definition", "version"]


class CertificationVersionViewSet(viewsets.ModelViewSet):
    queryset = CertificationVersion.objects.all()
    serializer_class = CertificationVersionSerializer


class CertificationSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Certification
        fields = [
            "name",
            "member",
            "certification_version",
            "certified_by",
            "date",
            "shop_lead_notified",
            "notes",
        ]


class CertificationViewSet(viewsets.ModelViewSet):
    queryset = Certification.objects.all()
    serializer_class = CertificationSerializer


router = routers.DefaultRouter()
router.register(r"paperwork/department", DepartmentViewSet)
router.register(r"paperwork/certification_definition", CertificationDefinitionViewSet)
router.register(r"paperwork/certification_version", CertificationVersionViewSet)
router.register(r"paperwork/certification", CertificationViewSet)