"""User API Views"""
from datetime import timedelta
from json import loads
from typing import Optional

from django.db.models.query import QuerySet
from django.db.transaction import atomic
from django.db.utils import IntegrityError
from django.urls import reverse_lazy
from django.utils.http import urlencode
from django.utils.text import slugify
from django.utils.timezone import now
from django.utils.translation import gettext as _
from django_filters.filters import BooleanFilter, CharFilter, ModelMultipleChoiceFilter
from django_filters.filterset import FilterSet
from drf_spectacular.types import OpenApiTypes
from drf_spectacular.utils import (
    OpenApiParameter,
    extend_schema,
    extend_schema_field,
    inline_serializer,
)
from guardian.shortcuts import get_anonymous_user, get_objects_for_user
from rest_framework.decorators import action
from rest_framework.fields import CharField, JSONField, SerializerMethodField
from rest_framework.permissions import IsAuthenticated
from rest_framework.request import Request
from rest_framework.response import Response
from rest_framework.serializers import (
    BooleanField,
    ListSerializer,
    ModelSerializer,
    PrimaryKeyRelatedField,
    Serializer,
    ValidationError,
)
from rest_framework.viewsets import ModelViewSet
from rest_framework_guardian.filters import ObjectPermissionsFilter
from structlog.stdlib import get_logger

from authentik.admin.api.metrics import CoordinateSerializer, get_events_per_1h
from authentik.api.decorators import permission_required
from authentik.core.api.groups import GroupSerializer
from authentik.core.api.used_by import UsedByMixin
from authentik.core.api.utils import LinkSerializer, PassiveSerializer, is_dict
from authentik.core.middleware import SESSION_IMPERSONATE_ORIGINAL_USER, SESSION_IMPERSONATE_USER
from authentik.core.models import (
    USER_ATTRIBUTE_SA,
    USER_ATTRIBUTE_TOKEN_EXPIRING,
    Group,
    Token,
    TokenIntents,
    User,
)
from authentik.events.models import EventAction
from authentik.stages.email.models import EmailStage
from authentik.stages.email.tasks import send_mails
from authentik.stages.email.utils import TemplateEmailMessage
from authentik.tenants.models import Tenant

LOGGER = get_logger()


class UserSerializer(ModelSerializer):
    """User Serializer"""

    is_superuser = BooleanField(read_only=True)
    avatar = CharField(read_only=True)
    attributes = JSONField(validators=[is_dict], required=False)
    groups = PrimaryKeyRelatedField(
        allow_empty=True, many=True, source="ak_groups", queryset=Group.objects.all()
    )
    groups_obj = ListSerializer(child=GroupSerializer(), read_only=True, source="ak_groups")
    uid = CharField(read_only=True)

    class Meta:

        model = User
        fields = [
            "pk",
            "username",
            "name",
            "is_active",
            "last_login",
            "is_superuser",
            "groups",
            "groups_obj",
            "email",
            "avatar",
            "attributes",
            "uid",
        ]
        extra_kwargs = {
            "name": {"allow_blank": True},
        }


class UserSelfSerializer(ModelSerializer):
    """User Serializer for information a user can retrieve about themselves and
    update about themselves"""

    is_superuser = BooleanField(read_only=True)
    avatar = CharField(read_only=True)
    groups = ListSerializer(child=GroupSerializer(), read_only=True, source="ak_groups")
    uid = CharField(read_only=True)

    class Meta:

        model = User
        fields = [
            "pk",
            "username",
            "name",
            "is_active",
            "is_superuser",
            "groups",
            "email",
            "avatar",
            "uid",
        ]
        extra_kwargs = {
            "is_active": {"read_only": True},
            "name": {"allow_blank": True},
        }


class SessionUserSerializer(PassiveSerializer):
    """Response for the /user/me endpoint, returns the currently active user (as `user` property)
    and, if this user is being impersonated, the original user in the `original` property."""

    user = UserSelfSerializer()
    original = UserSelfSerializer(required=False)


class UserMetricsSerializer(PassiveSerializer):
    """User Metrics"""

    logins_per_1h = SerializerMethodField()
    logins_failed_per_1h = SerializerMethodField()
    authorizations_per_1h = SerializerMethodField()

    @extend_schema_field(CoordinateSerializer(many=True))
    def get_logins_per_1h(self, _):
        """Get successful logins per hour for the last 24 hours"""
        user = self.context["user"]
        return get_events_per_1h(action=EventAction.LOGIN, user__pk=user.pk)

    @extend_schema_field(CoordinateSerializer(many=True))
    def get_logins_failed_per_1h(self, _):
        """Get failed logins per hour for the last 24 hours"""
        user = self.context["user"]
        return get_events_per_1h(action=EventAction.LOGIN_FAILED, context__username=user.username)

    @extend_schema_field(CoordinateSerializer(many=True))
    def get_authorizations_per_1h(self, _):
        """Get failed logins per hour for the last 24 hours"""
        user = self.context["user"]
        return get_events_per_1h(action=EventAction.AUTHORIZE_APPLICATION, user__pk=user.pk)


class UsersFilter(FilterSet):
    """Filter for users"""

    attributes = CharFilter(
        field_name="attributes",
        lookup_expr="",
        label="Attributes",
        method="filter_attributes",
    )

    is_superuser = BooleanFilter(field_name="ak_groups", lookup_expr="is_superuser")

    groups_by_name = ModelMultipleChoiceFilter(
        field_name="ak_groups__name",
        to_field_name="name",
        queryset=Group.objects.all(),
    )
    groups_by_pk = ModelMultipleChoiceFilter(
        field_name="ak_groups",
        queryset=Group.objects.all(),
    )

    # pylint: disable=unused-argument
    def filter_attributes(self, queryset, name, value):
        """Filter attributes by query args"""
        try:
            value = loads(value)
        except ValueError:
            raise ValidationError(detail="filter: failed to parse JSON")
        if not isinstance(value, dict):
            raise ValidationError(detail="filter: value must be key:value mapping")
        qs = {}
        for key, _value in value.items():
            qs[f"attributes__{key}"] = _value
        return queryset.filter(**qs)

    class Meta:
        model = User
        fields = [
            "username",
            "email",
            "name",
            "is_active",
            "is_superuser",
            "attributes",
            "groups_by_name",
            "groups_by_pk",
        ]


class UserViewSet(UsedByMixin, ModelViewSet):
    """User Viewset"""

    queryset = User.objects.none()
    ordering = ["username"]
    serializer_class = UserSerializer
    search_fields = ["username", "name", "is_active", "email"]
    filterset_class = UsersFilter

    def get_queryset(self):  # pragma: no cover
        return User.objects.all().exclude(pk=get_anonymous_user().pk)

    def _create_recovery_link(self) -> tuple[Optional[str], Optional[Token]]:
        """Create a recovery link (when the current tenant has a recovery flow set),
        that can either be shown to an admin or sent to the user directly"""
        tenant: Tenant = self.request._request.tenant
        # Check that there is a recovery flow, if not return an error
        flow = tenant.flow_recovery
        if not flow:
            LOGGER.debug("No recovery flow set")
            return None, None
        user: User = self.get_object()
        token, __ = Token.objects.get_or_create(
            identifier=f"{user.uid}-password-reset",
            user=user,
            intent=TokenIntents.INTENT_RECOVERY,
        )
        querystring = urlencode({"token": token.key})
        link = self.request.build_absolute_uri(
            reverse_lazy("authentik_core:if-flow", kwargs={"flow_slug": flow.slug})
            + f"?{querystring}"
        )
        return link, token

    @permission_required(None, ["authentik_core.add_user", "authentik_core.add_token"])
    @extend_schema(
        request=inline_serializer(
            "UserServiceAccountSerializer",
            {
                "name": CharField(required=True),
                "create_group": BooleanField(default=False),
            },
        ),
        responses={
            200: inline_serializer(
                "UserServiceAccountResponse",
                {
                    "username": CharField(required=True),
                    "token": CharField(required=True),
                },
            )
        },
    )
    @action(detail=False, methods=["POST"], pagination_class=None, filter_backends=[])
    def service_account(self, request: Request) -> Response:
        """Create a new user account that is marked as a service account"""
        username = request.data.get("name")
        create_group = request.data.get("create_group", False)
        with atomic():
            try:
                user = User.objects.create(
                    username=username,
                    name=username,
                    attributes={USER_ATTRIBUTE_SA: True, USER_ATTRIBUTE_TOKEN_EXPIRING: False},
                )
                if create_group:
                    group = Group.objects.create(
                        name=username,
                    )
                    group.users.add(user)
                token = Token.objects.create(
                    identifier=slugify(f"service-account-{username}-password"),
                    intent=TokenIntents.INTENT_APP_PASSWORD,
                    user=user,
                    expires=now() + timedelta(days=360),
                )
                return Response({"username": user.username, "token": token.key})
            except (IntegrityError) as exc:
                return Response(data={"non_field_errors": [str(exc)]}, status=400)

    @extend_schema(responses={200: SessionUserSerializer(many=False)})
    @action(detail=False, pagination_class=None, filter_backends=[])
    # pylint: disable=invalid-name
    def me(self, request: Request) -> Response:
        """Get information about current user"""
        serializer = SessionUserSerializer(data={"user": UserSelfSerializer(request.user).data})
        if SESSION_IMPERSONATE_USER in request._request.session:
            serializer.initial_data["original"] = UserSelfSerializer(
                request._request.session[SESSION_IMPERSONATE_ORIGINAL_USER]
            ).data
        serializer.is_valid()
        return Response(serializer.data)

    @extend_schema(request=UserSelfSerializer, responses={200: SessionUserSerializer(many=False)})
    @action(
        methods=["PUT"],
        detail=False,
        pagination_class=None,
        filter_backends=[],
        permission_classes=[IsAuthenticated],
    )
    def update_self(self, request: Request) -> Response:
        """Allow users to change information on their own profile"""
        data = UserSelfSerializer(instance=User.objects.get(pk=request.user.pk), data=request.data)
        if not data.is_valid():
            return Response(data.errors, status=400)
        new_user = data.save()
        # If we're impersonating, we need to update that user object
        # since it caches the full object
        if SESSION_IMPERSONATE_USER in request.session:
            request.session[SESSION_IMPERSONATE_USER] = new_user
        serializer = SessionUserSerializer(data={"user": UserSelfSerializer(request.user).data})
        serializer.is_valid()
        return Response(serializer.data)

    @permission_required("authentik_core.view_user", ["authentik_events.view_event"])
    @extend_schema(responses={200: UserMetricsSerializer(many=False)})
    @action(detail=True, pagination_class=None, filter_backends=[])
    # pylint: disable=invalid-name, unused-argument
    def metrics(self, request: Request, pk: int) -> Response:
        """User metrics per 1h"""
        user: User = self.get_object()
        serializer = UserMetricsSerializer(True)
        serializer.context["user"] = user
        return Response(serializer.data)

    @permission_required("authentik_core.reset_user_password")
    @extend_schema(
        responses={
            "200": LinkSerializer(many=False),
            "404": LinkSerializer(many=False),
        },
    )
    @action(detail=True, pagination_class=None, filter_backends=[])
    # pylint: disable=invalid-name, unused-argument
    def recovery(self, request: Request, pk: int) -> Response:
        """Create a temporary link that a user can use to recover their accounts"""
        link, _ = self._create_recovery_link()
        if not link:
            LOGGER.debug("Couldn't create token")
            return Response({"link": ""}, status=404)
        return Response({"link": link})

    @permission_required("authentik_core.reset_user_password")
    @extend_schema(
        parameters=[
            OpenApiParameter(
                name="email_stage",
                location=OpenApiParameter.QUERY,
                type=OpenApiTypes.STR,
                required=True,
            )
        ],
        responses={
            "204": Serializer(),
            "404": Serializer(),
        },
    )
    @action(detail=True, pagination_class=None, filter_backends=[])
    # pylint: disable=invalid-name, unused-argument
    def recovery_email(self, request: Request, pk: int) -> Response:
        """Create a temporary link that a user can use to recover their accounts"""
        for_user = self.get_object()
        if for_user.email == "":
            LOGGER.debug("User doesn't have an email address")
            return Response(status=404)
        link, token = self._create_recovery_link()
        if not link:
            LOGGER.debug("Couldn't create token")
            return Response(status=404)
        # Lookup the email stage to assure the current user can access it
        stages = get_objects_for_user(
            request.user, "authentik_stages_email.view_emailstage"
        ).filter(pk=request.query_params.get("email_stage"))
        if not stages.exists():
            LOGGER.debug("Email stage does not exist/user has no permissions")
            return Response(status=404)
        email_stage: EmailStage = stages.first()
        message = TemplateEmailMessage(
            subject=_(email_stage.subject),
            template_name=email_stage.template,
            to=[for_user.email],
            template_context={
                "url": link,
                "user": for_user,
                "expires": token.expires,
            },
        )
        send_mails(email_stage, message)
        return Response(status=204)

    def _filter_queryset_for_list(self, queryset: QuerySet) -> QuerySet:
        """Custom filter_queryset method which ignores guardian, but still supports sorting"""
        for backend in list(self.filter_backends):
            if backend == ObjectPermissionsFilter:
                continue
            queryset = backend().filter_queryset(self.request, queryset, self)
        return queryset

    def filter_queryset(self, queryset):
        if self.request.user.has_perm("authentik_core.view_user"):
            return self._filter_queryset_for_list(queryset)
        return super().filter_queryset(queryset)