from textwrap import dedent

from django.contrib.auth.models import AnonymousUser
from django.db import transaction
from django.db.utils import IntegrityError
from rest_framework import status

from openslides.utils.auth import in_some_groups
from openslides.utils.autoupdate import inform_changed_data
from openslides.utils.rest_api import (
    DecimalField,
    GenericViewSet,
    ListModelMixin,
    ModelViewSet,
    Response,
    RetrieveModelMixin,
    ValidationError,
    detail_route,
)

from .models import BasePoll


class BasePollViewSet(ModelViewSet):
    valid_update_keys = [
        "majority_method",
        "onehundred_percent_base",
        "title",
        "description",
    ]

    def check_view_permissions(self):
        """
        the vote view is checked seperately. For all other views manage permissions
        are required.
        """
        if self.action == "vote":
            return True
        else:
            return self.has_manage_permissions()

    @transaction.atomic
    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)

        # for analog polls, votes can be given directly when the poll is created
        # for assignment polls, the options do not exist yet, so the AssignmentRelatedUser ids are needed
        if "votes" in request.data:
            poll = serializer.save()
            poll.create_options()
            self.handle_request_with_votes(request, poll)
        else:
            self.perform_create(serializer)

        headers = self.get_success_headers(serializer.data)
        return Response(
            serializer.data, status=status.HTTP_201_CREATED, headers=headers
        )

    def perform_create(self, serializer):
        poll = serializer.save()
        poll.create_options()

    @transaction.atomic
    def update(self, request, *args, **kwargs):
        """
        Customized view endpoint to update a poll.
        """
        poll = self.get_object()

        partial = kwargs.get("partial", False)
        serializer = self.get_serializer(poll, data=request.data, partial=partial)
        serializer.is_valid(raise_exception=False)

        if poll.state != BasePoll.STATE_CREATED:
            invalid_keys = set(serializer.validated_data.keys()) - set(
                self.valid_update_keys
            )
            if len(invalid_keys):
                raise ValidationError(
                    {
                        "detail": dedent(
                            f"""
                            The poll is not in the created state.
                            You can only edit: {', '.join(self.valid_update_keys)}.
                            You provided the invalid keys: {', '.join(invalid_keys)}.
                        """
                        )
                    }
                )

        if "votes" in request.data:
            self.handle_request_with_votes(request, poll)
        return super().update(request, *args, **kwargs)

    def handle_request_with_votes(self, request, poll):
        if poll.type != BasePoll.TYPE_ANALOG:
            raise ValidationError(
                {"detail": "You cannot enter votes for a non-analog poll."}
            )

        vote_data = request.data["votes"]
        # convert user ids to option ids
        self.convert_option_data(poll, vote_data)

        self.validate_vote_data(vote_data, poll, request.user)
        self.handle_analog_vote(vote_data, poll, request.user)

        if request.data.get("publish_immediately"):
            poll.state = BasePoll.STATE_PUBLISHED
        elif (
            poll.state != BasePoll.STATE_PUBLISHED
        ):  # only set to finished if not already published
            poll.state = BasePoll.STATE_FINISHED
        poll.save()

    @detail_route(methods=["POST"])
    @transaction.atomic
    def start(self, request, pk):
        poll = self.get_object()
        if poll.state != BasePoll.STATE_CREATED:
            raise ValidationError({"detail": "Wrong poll state"})
        poll.state = BasePoll.STATE_STARTED

        poll.save()
        inform_changed_data(poll.get_votes())
        return Response()

    @detail_route(methods=["POST"])
    @transaction.atomic
    def stop(self, request, pk):
        poll = self.get_object()
        # Analog polls could not be stopped; they are stopped when
        # the results are entered.
        if poll.type == BasePoll.TYPE_ANALOG:
            raise ValidationError(
                {"detail": "Analog polls can not be stopped. Please enter votes."}
            )

        if poll.state != BasePoll.STATE_STARTED:
            raise ValidationError({"detail": "Wrong poll state"})

        poll.state = BasePoll.STATE_FINISHED
        poll.save()
        inform_changed_data(poll.get_votes())
        inform_changed_data(poll.get_options())
        return Response()

    @detail_route(methods=["POST"])
    @transaction.atomic
    def publish(self, request, pk):
        poll = self.get_object()
        if poll.state != BasePoll.STATE_FINISHED:
            raise ValidationError({"detail": "Wrong poll state"})

        poll.state = BasePoll.STATE_PUBLISHED
        poll.save()
        inform_changed_data(poll.get_votes())
        inform_changed_data(poll.get_options())
        return Response()

    @detail_route(methods=["POST"])
    @transaction.atomic
    def pseudoanonymize(self, request, pk):
        poll = self.get_object()

        if poll.state not in (BasePoll.STATE_FINISHED, BasePoll.STATE_PUBLISHED):
            raise ValidationError(
                {"detail": "Pseudoanonmizing can only be done after a finished poll"}
            )
        if poll.type != BasePoll.TYPE_NAMED:
            raise ValidationError(
                {"detail": "You can just pseudoanonymize named polls"}
            )

        poll.pseudoanonymize()
        return Response()

    @detail_route(methods=["POST"])
    @transaction.atomic
    def reset(self, request, pk):
        poll = self.get_object()
        poll.reset()
        return Response()

    @detail_route(methods=["POST"])
    @transaction.atomic
    def vote(self, request, pk):
        """
        For motion polls: Just "Y", "N" or "A" (if pollmethod is "YNA")
        """
        poll = self.get_object()

        if isinstance(request.user, AnonymousUser):
            self.permission_denied(request)

        # check permissions based on poll type and handle requests
        self.assert_can_vote(poll, request)

        data = request.data
        self.validate_vote_data(data, poll, request.user)

        if poll.type == BasePoll.TYPE_ANALOG:
            self.handle_analog_vote(data, poll, request.user)
            if request.data.get("publish_immediately") == "1":
                poll.state = BasePoll.STATE_PUBLISHED
            else:
                poll.state = BasePoll.STATE_FINISHED
            poll.save()

        elif poll.type == BasePoll.TYPE_NAMED:
            self.handle_named_vote(data, poll, request.user)

        elif poll.type == BasePoll.TYPE_PSEUDOANONYMOUS:
            self.handle_pseudoanonymous_vote(data, poll, request.user)

        inform_changed_data(poll)

        return Response()

    def assert_can_vote(self, poll, request):
        """
        Raises a permission denied, if the user is not allowed to vote (or has already voted).
        Adds the user to the voted array, so this needs to be reverted on error!
        Analog:                     has to have manage permissions
        Named & Pseudoanonymous:    has to be in a poll group and present
        """
        if poll.type == BasePoll.TYPE_ANALOG:
            if not self.has_manage_permissions():
                self.permission_denied(request)
        else:
            if poll.state != BasePoll.STATE_STARTED:
                raise ValidationError("You can only vote on a started poll.")
            if not request.user.is_present or not in_some_groups(
                request.user.id,
                list(poll.groups.values_list("pk", flat=True)),
                exact=True,
            ):
                self.permission_denied(request)

            try:
                self.add_user_to_voted_array(request.user, poll)
                inform_changed_data(poll)
            except IntegrityError:
                raise ValidationError({"detail": "You have already voted"})

    def parse_vote_value(self, obj, key):
        """ Raises a ValidationError on incorrect values, including None """
        if key not in obj:
            raise ValidationError({"detail": f"The field {key} is required"})
        field = DecimalField(min_value=-2, max_digits=15, decimal_places=6)
        value = field.to_internal_value(obj[key])
        if value < 0 and value != -1 and value != -2:
            raise ValidationError(
                {
                    "detail": "No fractional negative values allowed, only the special values -1 and -2"
                }
            )
        return value

    def convert_option_data(self, poll, data):
        """
        May be overwritten by subclass. Adjusts the option data based on the now existing poll
        """
        pass

    def add_user_to_voted_array(self, user, poll):
        """
        To be implemented by subclass. Adds the given user to the voted array of the given poll.
        Throws an IntegrityError if the user already exists in the array
        """
        raise NotImplementedError()

    def validate_vote_data(self, data, poll, user):
        """
        To be implemented by subclass. Validates the data according to poll type and method and fields by validated versions.
        Raises ValidationError on failure
        """
        raise NotImplementedError()

    def handle_analog_vote(self, data, poll, user):
        """
        To be implemented by subclass. Handles the analog vote. Assumes data is validated
        """
        raise NotImplementedError()

    def handle_named_vote(self, data, poll, user):
        """
        To be implemented by subclass. Handles the named vote. Assumes data is validated.
        Needs to manage the voted-array per option.
        """
        raise NotImplementedError()

    def handle_pseudoanonymous_vote(self, data, poll, user):
        """
        To be implemented by subclass. Handles the pseudoanonymous vote. Assumes data
        is validated. Needs to check, if the vote is allowed by the voted-array per poll.
        Needs to add the user to the voted-array.
        """
        raise NotImplementedError()


class BaseVoteViewSet(ListModelMixin, RetrieveModelMixin, GenericViewSet):
    pass


class BaseOptionViewSet(ListModelMixin, RetrieveModelMixin, GenericViewSet):
    pass