from typing import TYPE_CHECKING

from ajax_select import make_ajax_field
from ajax_select.fields import AutoCompleteSelectField
from django import forms
from django.core.exceptions import PermissionDenied
from django.db import transaction
from django.db.models.query import QuerySet
from django.shortcuts import get_object_or_404, redirect
from django.urls import reverse, reverse_lazy
from django.utils.translation import gettext_lazy as _
from django.views.generic import DetailView, ListView
from django.views.generic.edit import CreateView, DeleteView, FormView, UpdateView

from core.views import CanCreateMixin, CanEditMixin, CanViewMixin
from core.views.forms import MarkdownInput, SelectDateTime
from election.models import Candidature, Election, ElectionList, Role, Vote

if TYPE_CHECKING:
    from core.models import User


# Custom form field


class LimitedCheckboxField(forms.ModelMultipleChoiceField):
    """A `ModelMultipleChoiceField`, with a max limit of selectable inputs."""

    def __init__(self, queryset, max_choice, **kwargs):
        self.max_choice = max_choice
        super().__init__(queryset, **kwargs)

    def clean(self, value):
        qs = super().clean(value)
        self.validate(qs)
        return qs

    def validate(self, qs):
        if qs.count() > self.max_choice:
            raise forms.ValidationError(
                _("You have selected too much candidates."), code="invalid"
            )


# Forms


class CandidateForm(forms.ModelForm):
    """Form to candidate."""

    class Meta:
        model = Candidature
        fields = ["user", "role", "program", "election_list"]
        widgets = {"program": MarkdownInput}

    user = AutoCompleteSelectField(
        "users", label=_("User to candidate"), help_text=None, required=True
    )

    def __init__(self, *args, **kwargs):
        election_id = kwargs.pop("election_id", None)
        can_edit = kwargs.pop("can_edit", False)
        super().__init__(*args, **kwargs)
        if election_id:
            self.fields["role"].queryset = Role.objects.filter(
                election__id=election_id
            ).all()
            self.fields["election_list"].queryset = ElectionList.objects.filter(
                election__id=election_id
            ).all()
        if not can_edit:
            self.fields["user"].widget = forms.HiddenInput()


class VoteForm(forms.Form):
    def __init__(self, election, user, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if not election.has_voted(user):
            for role in election.roles.all():
                cand = role.candidatures
                if role.max_choice > 1:
                    self.fields[role.title] = LimitedCheckboxField(
                        cand, role.max_choice, required=False
                    )
                else:
                    self.fields[role.title] = forms.ModelChoiceField(
                        cand,
                        required=False,
                        widget=forms.RadioSelect(),
                        empty_label=_("Blank vote"),
                    )


class RoleForm(forms.ModelForm):
    """Form for creating a role."""

    class Meta:
        model = Role
        fields = ["title", "election", "description", "max_choice"]

    def __init__(self, *args, **kwargs):
        election_id = kwargs.pop("election_id", None)
        super().__init__(*args, **kwargs)
        if election_id:
            self.fields["election"].queryset = Election.objects.filter(
                id=election_id
            ).all()

    def clean(self):
        cleaned_data = super().clean()
        title = cleaned_data.get("title")
        election = cleaned_data.get("election")
        if Role.objects.filter(title=title, election=election).exists():
            raise forms.ValidationError(
                _("This role already exists for this election"), code="invalid"
            )


class ElectionListForm(forms.ModelForm):
    class Meta:
        model = ElectionList
        fields = ("title", "election")

    def __init__(self, *args, **kwargs):
        election_id = kwargs.pop("election_id", None)
        super().__init__(*args, **kwargs)
        if election_id:
            self.fields["election"].queryset = Election.objects.filter(
                id=election_id
            ).all()


class ElectionForm(forms.ModelForm):
    class Meta:
        model = Election
        fields = [
            "title",
            "description",
            "archived",
            "start_candidature",
            "end_candidature",
            "start_date",
            "end_date",
            "edit_groups",
            "view_groups",
            "vote_groups",
            "candidature_groups",
        ]

    edit_groups = make_ajax_field(
        Election, "edit_groups", "groups", help_text="", label=_("edit groups")
    )
    view_groups = make_ajax_field(
        Election, "view_groups", "groups", help_text="", label=_("view groups")
    )
    vote_groups = make_ajax_field(
        Election, "vote_groups", "groups", help_text="", label=_("vote groups")
    )
    candidature_groups = make_ajax_field(
        Election,
        "candidature_groups",
        "groups",
        help_text="",
        label=_("candidature groups"),
    )

    start_date = forms.DateTimeField(
        label=_("Start date"), widget=SelectDateTime, required=True
    )
    end_date = forms.DateTimeField(
        label=_("End date"), widget=SelectDateTime, required=True
    )
    start_candidature = forms.DateTimeField(
        label=_("Start candidature"), widget=SelectDateTime, required=True
    )
    end_candidature = forms.DateTimeField(
        label=_("End candidature"), widget=SelectDateTime, required=True
    )


# Display elections


class ElectionsListView(CanViewMixin, ListView):
    """A list of all non archived elections visible."""

    model = Election
    ordering = ["-id"]
    paginate_by = 10
    template_name = "election/election_list.jinja"

    def get_queryset(self):
        return super().get_queryset().filter(archived=False).all()


class ElectionListArchivedView(CanViewMixin, ListView):
    """A list of all archived elections visible."""

    model = Election
    ordering = ["-id"]
    paginate_by = 10
    template_name = "election/election_list.jinja"

    def get_queryset(self):
        return super().get_queryset().filter(archived=True).all()


class ElectionDetailView(CanViewMixin, DetailView):
    """Details an election responsability by responsability."""

    model = Election
    template_name = "election/election_detail.jinja"
    pk_url_kwarg = "election_id"

    def get(self, request, *arg, **kwargs):
        response = super().get(request, *arg, **kwargs)
        election: Election = self.get_object()
        if request.user.can_edit(election) and election.is_vote_editable:
            action = request.GET.get("action", None)
            role = request.GET.get("role", None)
            if action and role and Role.objects.filter(id=role).exists():
                if action == "up":
                    Role.objects.get(id=role).up()
                elif action == "down":
                    Role.objects.get(id=role).down()
                elif action == "bottom":
                    Role.objects.get(id=role).bottom()
                elif action == "top":
                    Role.objects.get(id=role).top()
                return redirect(
                    reverse("election:detail", kwargs={"election_id": election.id})
                )
        return response

    def get_context_data(self, **kwargs):
        """Add additionnal data to the template."""
        kwargs = super().get_context_data(**kwargs)
        kwargs["election_form"] = VoteForm(self.object, self.request.user)
        kwargs["election_results"] = self.object.results
        return kwargs


# Form view


class VoteFormView(CanCreateMixin, FormView):
    """Alows users to vote."""

    form_class = VoteForm
    template_name = "election/election_detail.jinja"

    def dispatch(self, request, *arg, **kwargs):
        self.election = get_object_or_404(Election, pk=kwargs["election_id"])
        return super().dispatch(request, *arg, **kwargs)

    def vote(self, election_data):
        with transaction.atomic():
            for role_title in election_data:
                # If we have a multiple choice field
                if isinstance(election_data[role_title], QuerySet):
                    if election_data[role_title].count() > 0:
                        vote = Vote(role=election_data[role_title].first().role)
                        vote.save()
                    for el in election_data[role_title]:
                        vote.candidature.add(el)
                # If we have a single choice
                elif election_data[role_title] is not None:
                    vote = Vote(role=election_data[role_title].role)
                    vote.save()
                    vote.candidature.add(election_data[role_title])
            self.election.voters.add(self.request.user)

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["election"] = self.election
        kwargs["user"] = self.request.user
        return kwargs

    def form_valid(self, form):
        """Verify that the user is part in a vote group."""
        data = form.clean()
        res = super(FormView, self).form_valid(form)
        for grp_id in self.election.vote_groups.values_list("pk", flat=True):
            if self.request.user.is_in_group(pk=grp_id):
                self.vote(data)
                return res
        return res

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.election.id})

    def get_context_data(self, **kwargs):
        """Add additionnal data to the template."""
        kwargs = super().get_context_data(**kwargs)
        kwargs["object"] = self.election
        kwargs["election"] = self.election
        kwargs["election_form"] = self.get_form()
        return kwargs


# Create views


class CandidatureCreateView(CanCreateMixin, CreateView):
    """View dedicated to a cundidature creation."""

    form_class = CandidateForm
    model = Candidature
    template_name = "election/candidate_form.jinja"

    def dispatch(self, request, *arg, **kwargs):
        self.election = get_object_or_404(Election, pk=kwargs["election_id"])
        return super().dispatch(request, *arg, **kwargs)

    def get_initial(self):
        init = {}
        self.can_edit = self.request.user.can_edit(self.election)
        init["user"] = self.request.user.id
        return init

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["election_id"] = self.election.id
        kwargs["can_edit"] = self.can_edit
        return kwargs

    def form_valid(self, form):
        """Verify that the selected user is in candidate group."""
        obj = form.instance
        obj.election = Election.objects.get(id=self.election.id)
        if (obj.election.can_candidate(obj.user)) and (
            obj.user == self.request.user or self.can_edit
        ):
            return super(CreateView, self).form_valid(form)
        raise PermissionDenied

    def get_context_data(self, **kwargs):
        kwargs = super().get_context_data(**kwargs)
        kwargs["election"] = self.election
        return kwargs

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.election.id})


class ElectionCreateView(CanCreateMixin, CreateView):
    model = Election
    form_class = ElectionForm
    template_name = "core/create.jinja"

    def dispatch(self, request, *args, **kwargs):
        if not request.user.is_subscribed:
            raise PermissionDenied
        return super().dispatch(request, *args, **kwargs)

    def form_valid(self, form):
        """Allow every user that had passed the dispatch to create an election."""
        return super(CreateView, self).form_valid(form)

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.object.id})


class RoleCreateView(CanCreateMixin, CreateView):
    model = Role
    form_class = RoleForm
    template_name = "core/create.jinja"

    def dispatch(self, request, *arg, **kwargs):
        self.election = get_object_or_404(Election, pk=kwargs["election_id"])
        if not self.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *arg, **kwargs)

    def get_initial(self):
        init = {}
        init["election"] = self.election
        return init

    def form_valid(self, form):
        """Verify that the user can edit properly."""
        obj: Role = form.instance
        user: User = self.request.user
        if obj.election:
            for grp_id in obj.election.edit_groups.values_list("pk", flat=True):
                if user.is_in_group(pk=grp_id):
                    return super(CreateView, self).form_valid(form)
        raise PermissionDenied

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["election_id"] = self.election.id
        return kwargs

    def get_success_url(self, **kwargs):
        return reverse_lazy(
            "election:detail", kwargs={"election_id": self.object.election.id}
        )


class ElectionListCreateView(CanCreateMixin, CreateView):
    model = ElectionList
    form_class = ElectionListForm
    template_name = "core/create.jinja"

    def dispatch(self, request, *arg, **kwargs):
        self.election = get_object_or_404(Election, pk=kwargs["election_id"])
        if not self.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *arg, **kwargs)

    def get_initial(self):
        init = {}
        init["election"] = self.election
        return init

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["election_id"] = self.election.id
        return kwargs

    def form_valid(self, form):
        """Verify that the user can vote on this election."""
        obj: ElectionList = form.instance
        user: User = self.request.user
        if obj.election:
            for grp_id in obj.election.candidature_groups.values_list("pk", flat=True):
                if user.is_in_group(pk=grp_id):
                    return super(CreateView, self).form_valid(form)
            for grp_id in obj.election.edit_groups.values_list("pk", flat=True):
                if user.is_in_group(pk=grp_id):
                    return super(CreateView, self).form_valid(form)
        raise PermissionDenied

    def get_success_url(self, **kwargs):
        return reverse_lazy(
            "election:detail", kwargs={"election_id": self.object.election.id}
        )


# Update view


class ElectionUpdateView(CanEditMixin, UpdateView):
    model = Election
    form_class = ElectionForm
    template_name = "core/edit.jinja"
    pk_url_kwarg = "election_id"

    def get_initial(self):
        return {
            "start_date": self.object.start_date.strftime("%Y-%m-%d %H:%M:%S"),
            "end_date": self.object.end_date.strftime("%Y-%m-%d %H:%M:%S"),
            "start_candidature": self.object.start_candidature.strftime(
                "%Y-%m-%d %H:%M:%S"
            ),
            "end_candidature": self.object.end_candidature.strftime(
                "%Y-%m-%d %H:%M:%S"
            ),
        }

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.object.id})


class CandidatureUpdateView(CanEditMixin, UpdateView):
    model = Candidature
    form_class = CandidateForm
    template_name = "core/edit.jinja"
    pk_url_kwarg = "candidature_id"

    def dispatch(self, request, *arg, **kwargs):
        self.object = self.get_object()
        if not self.object.role.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *arg, **kwargs)

    def remove_fields(self):
        self.form.fields.pop("role", None)

    def get(self, request, *args, **kwargs):
        self.form = self.get_form()
        self.remove_fields()
        return self.render_to_response(self.get_context_data(form=self.form))

    def post(self, request, *args, **kwargs):
        self.form = self.get_form()
        self.remove_fields()
        if (
            request.user.is_authenticated
            and request.user.can_edit(self.object)
            and self.form.is_valid()
        ):
            return super().form_valid(self.form)
        return self.form_invalid(self.form)

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["election_id"] = self.object.role.election.id
        return kwargs

    def get_success_url(self, **kwargs):
        return reverse_lazy(
            "election:detail", kwargs={"election_id": self.object.role.election.id}
        )


class RoleUpdateView(CanEditMixin, UpdateView):
    model = Role
    form_class = RoleForm
    template_name = "core/edit.jinja"
    pk_url_kwarg = "role_id"

    def dispatch(self, request, *arg, **kwargs):
        self.object = self.get_object()
        if not self.object.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *arg, **kwargs)

    def remove_fields(self):
        self.form.fields.pop("election", None)

    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        self.form = self.get_form()
        self.remove_fields()
        return self.render_to_response(self.get_context_data(form=self.form))

    def post(self, request, *args, **kwargs):
        self.object = self.get_object()
        self.form = self.get_form()
        self.remove_fields()
        if (
            request.user.is_authenticated
            and request.user.can_edit(self.object)
            and self.form.is_valid()
        ):
            return super().form_valid(self.form)
        return self.form_invalid(self.form)

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["election_id"] = self.object.election.id
        return kwargs

    def get_success_url(self, **kwargs):
        return reverse_lazy(
            "election:detail", kwargs={"election_id": self.object.election.id}
        )


# Delete Views


class ElectionDeleteView(DeleteView):
    model = Election
    template_name = "core/delete_confirm.jinja"
    pk_url_kwarg = "election_id"

    def dispatch(self, request, *args, **kwargs):
        if request.user.is_root:
            return super().dispatch(request, *args, **kwargs)
        raise PermissionDenied

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:list")


class CandidatureDeleteView(CanEditMixin, DeleteView):
    model = Candidature
    template_name = "core/delete_confirm.jinja"
    pk_url_kwarg = "candidature_id"

    def dispatch(self, request, *arg, **kwargs):
        self.object = self.get_object()
        self.election = self.object.role.election
        if not self.election.can_candidate or not self.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *arg, **kwargs)

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.election.id})


class RoleDeleteView(CanEditMixin, DeleteView):
    model = Role
    template_name = "core/delete_confirm.jinja"
    pk_url_kwarg = "role_id"

    def dispatch(self, request, *arg, **kwargs):
        self.object = self.get_object()
        self.election = self.object.election
        if not self.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *arg, **kwargs)

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.election.id})


class ElectionListDeleteView(CanEditMixin, DeleteView):
    model = ElectionList
    template_name = "core/delete_confirm.jinja"
    pk_url_kwarg = "list_id"

    def dispatch(self, request, *args, **kwargs):
        self.object = self.get_object()
        self.election = self.object.election
        if not self.election.is_vote_editable:
            raise PermissionDenied
        return super().dispatch(request, *args, **kwargs)

    def get_success_url(self, **kwargs):
        return reverse_lazy("election:detail", kwargs={"election_id": self.election.id})