"""Views for displaying or manipulating instances of :class:`Relationship`."""

import typing

from django.contrib.auth.mixins import LoginRequiredMixin
from django.urls import reverse
from django.utils import timezone
from django.views.generic import DetailView, RedirectView, UpdateView

from people import forms, models, permissions


class RelationshipDetailView(permissions.UserIsLinkedPersonMixin, DetailView):
    """
    View displaying details of a :class:`Relationship`.
    """
    model = models.Relationship
    template_name = 'people/relationship/detail.html'
    related_person_field = 'source'


class RelationshipCreateView(LoginRequiredMixin, RedirectView):
    """View for creating a :class:`Relationship`.

    Redirects to a form containing the :class:`RelationshipQuestion`s.
    """
    def get_redirect_url(self, *args: typing.Any,
                         **kwargs: typing.Any) -> typing.Optional[str]:
        target = models.Person.objects.get(pk=self.kwargs.get('person_pk'))
        relationship, _ = models.Relationship.objects.get_or_create(
            source=self.request.user.person, target=target)

        return reverse('people:relationship.update',
                       kwargs={'pk': relationship.pk})


class RelationshipUpdateView(permissions.UserIsLinkedPersonMixin, UpdateView):
    """View for updating the details of a relationship.

    Creates a new :class:`RelationshipAnswerSet` for the :class:`Relationship`.
    Displays / processes a form containing the :class:`RelationshipQuestion`s.
    """
    model = models.Relationship
    context_object_name = 'relationship'
    template_name = 'people/relationship/update.html'
    form_class = forms.RelationshipAnswerSetForm

    def get_test_person(self) -> models.Person:
        """Get the person instance which should be used for access control checks."""
        return self.object.source

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['person'] = self.object.source
        return context

    def get_initial(self):
        try:
            previous_answers = self.object.current_answers.as_dict()

        except AttributeError:
            previous_answers = {}

        previous_answers.update({
            'relationship': self.object,
        })

        return previous_answers

    def get_form_kwargs(self) -> typing.Dict[str, typing.Any]:
        """Remove instance from form kwargs as it's a person, but expects a PersonAnswerSet."""
        kwargs = super().get_form_kwargs()
        kwargs.pop('instance')

        return kwargs

    def form_valid(self, form):
        """Mark any previous answer sets as replaced."""
        response = super().form_valid(form)
        now_date = timezone.now().date()

        # Shouldn't be more than one after initial updates after migration
        for answer_set in self.object.relationship.answer_sets.exclude(
                pk=self.object.pk):
            answer_set.replaced_timestamp = now_date
            answer_set.save()

        return response

    def get_success_url(self) -> str:
        return self.object.get_absolute_url()


class OrganisationRelationshipDetailView(permissions.UserIsLinkedPersonMixin,
                                         DetailView):
    """View displaying details of an :class:`OrganisationRelationship`."""
    model = models.OrganisationRelationship
    template_name = 'people/organisation-relationship/detail.html'
    related_person_field = 'source'
    context_object_name = 'relationship'


class OrganisationRelationshipCreateView(LoginRequiredMixin, RedirectView):
    """View for creating a :class:`OrganisationRelationship`.

    Redirects to a form containing the :class:`OrganisationRelationshipQuestion`s.
    """
    def get_redirect_url(self, *args: typing.Any,
                         **kwargs: typing.Any) -> typing.Optional[str]:
        target = models.Organisation.objects.get(
            pk=self.kwargs.get('organisation_pk'))
        relationship, _ = models.OrganisationRelationship.objects.get_or_create(
            source=self.request.user.person, target=target)

        return reverse('people:organisation.relationship.update',
                       kwargs={'pk': relationship.pk})


class OrganisationRelationshipUpdateView(RelationshipUpdateView):
    """View for updating the details of a Organisationrelationship.

    Creates a new :class:`OrganisationRelationshipAnswerSet` for the :class:`OrganisationRelationship`.
    Displays / processes a form containing the :class:`OrganisationRelationshipQuestion`s.
    """
    model = models.OrganisationRelationship
    context_object_name = 'relationship'
    template_name = 'people/relationship/update.html'
    form_class = forms.OrganisationRelationshipAnswerSetForm