#
# Copyright 2016,2017
# - Skia <skia@libskia.so>
# - Sli <antoine@bartuccio.fr>
#
# Ce fichier fait partie du site de l'Association des Étudiants de l'UTBM,
# http://ae.utbm.fr.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License a published by the Free Software
# Foundation; either version 3 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Sofware Foundation, Inc., 59 Temple
# Place - Suite 330, Boston, MA 02111-1307, USA.
#
#

from django import forms
from django.conf import settings
from django.db.models import Exists, OuterRef, Q
from django.db.models.functions import Lower
from django.utils.translation import gettext_lazy as _

from club.models import Club, Mailing, MailingSubscription, Membership
from core.models import User
from core.views.forms import SelectDateTime
from core.views.widgets.ajax_select import (
    AutoCompleteSelectMultipleUser,
    AutoCompleteSelectUser,
)
from counter.models import Counter, Selling


class ClubEditForm(forms.ModelForm):
    error_css_class = "error"
    required_css_class = "required"

    class Meta:
        model = Club
        fields = ["address", "logo", "short_description"]
        widgets = {"short_description": forms.Textarea()}


class ClubAdminEditForm(ClubEditForm):
    admin_fields = ["name", "parent", "is_active"]

    class Meta(ClubEditForm.Meta):
        fields = ["name", "parent", "is_active", *ClubEditForm.Meta.fields]


class MailingForm(forms.Form):
    """Form handling mailing lists right."""

    ACTION_NEW_MAILING = 1
    ACTION_NEW_SUBSCRIPTION = 2
    ACTION_REMOVE_SUBSCRIPTION = 3

    subscription_users = forms.ModelMultipleChoiceField(
        label=_("Users to add"),
        help_text=_("Search users to add (one or more)."),
        required=False,
        widget=AutoCompleteSelectMultipleUser,
        queryset=User.objects.all(),
    )

    def __init__(self, club_id, user_id, mailings, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.fields["action"] = forms.TypedChoiceField(
            choices=(
                (self.ACTION_NEW_MAILING, _("New Mailing")),
                (self.ACTION_NEW_SUBSCRIPTION, _("Subscribe")),
                (self.ACTION_REMOVE_SUBSCRIPTION, _("Remove")),
            ),
            coerce=int,
            label=_("Action"),
            initial=1,
            required=True,
            widget=forms.HiddenInput(),
        )

        # Generate bulk removal forms, they are never required
        for mailing in mailings:
            self.fields["removal_" + str(mailing.id)] = forms.ModelMultipleChoiceField(
                mailing.subscriptions.all(),
                label=_("Remove"),
                required=False,
                widget=forms.CheckboxSelectMultiple,
            )

        # Include fields for handling mailing creation
        mailing_fields = ("email",)
        self.fields.update(forms.fields_for_model(Mailing, fields=mailing_fields))
        for field in mailing_fields:
            self.fields["mailing_" + field] = self.fields.pop(field)
            self.fields["mailing_" + field].required = False

        # Include fields for handling subscription creation
        subscription_fields = ("mailing", "email")
        self.fields.update(
            forms.fields_for_model(MailingSubscription, fields=subscription_fields)
        )
        for field in subscription_fields:
            self.fields["subscription_" + field] = self.fields.pop(field)
            self.fields["subscription_" + field].required = False

        self.fields["subscription_mailing"].queryset = Mailing.objects.filter(
            club__id=club_id, is_moderated=True
        )

    def check_required(self, cleaned_data, field):
        """If the given field doesn't exist or has no value, add a required error on it."""
        if not cleaned_data.get(field, None):
            self.add_error(field, _("This field is required"))

    def clean_subscription_users(self):
        """Convert given users into real users and check their validity."""
        cleaned_data = super().clean()
        users = []
        for user in cleaned_data["subscription_users"]:
            if not user.email:
                raise forms.ValidationError(
                    _("One of the selected users doesn't have an email address"),
                    code="invalid",
                )
            users.append(user)
        return users

    def clean(self):
        cleaned_data = super().clean()

        if "action" not in cleaned_data:
            # If there is no action provided, we can stop here
            raise forms.ValidationError(_("An action is required"), code="invalid")

        if cleaned_data["action"] == self.ACTION_NEW_MAILING:
            self.check_required(cleaned_data, "mailing_email")

        if cleaned_data["action"] == self.ACTION_NEW_SUBSCRIPTION:
            self.check_required(cleaned_data, "subscription_mailing")
            if not cleaned_data.get(
                "subscription_users", None
            ) and not cleaned_data.get("subscription_email", None):
                raise forms.ValidationError(
                    _("You must specify at least an user or an email address"),
                    code="invalid",
                )

        return cleaned_data


class SellingsForm(forms.Form):
    begin_date = forms.DateTimeField(
        label=_("Begin date"), widget=SelectDateTime, required=False
    )
    end_date = forms.DateTimeField(
        label=_("End date"), widget=SelectDateTime, required=False
    )

    def __init__(self, club, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # postgres struggles really hard with a single query having three WHERE conditions,
        # but deals perfectly fine with UNION of multiple queryset with their own WHERE clause,
        # so we do this to get the ids, which we use to build another queryset that can be used by django.
        club_sales_subquery = Selling.objects.filter(counter=OuterRef("pk"), club=club)
        ids = (
            Counter.objects.filter(Q(club=club) | Q(products__club=club))
            .union(Counter.objects.filter(Exists(club_sales_subquery)))
            .values_list("id", flat=True)
        )
        counters_qs = Counter.objects.filter(id__in=ids).order_by(Lower("name"))
        self.fields["counters"] = forms.ModelMultipleChoiceField(
            counters_qs, label=_("Counter"), required=False
        )
        self.fields["products"] = forms.ModelMultipleChoiceField(
            club.products.order_by("name").filter(archived=False).all(),
            label=_("Products"),
            required=False,
        )
        self.fields["archived_products"] = forms.ModelMultipleChoiceField(
            club.products.order_by("name").filter(archived=True).all(),
            label=_("Archived products"),
            required=False,
        )


class ClubOldMemberForm(forms.Form):
    members_old = forms.ModelMultipleChoiceField(
        Membership.objects.none(),
        label=_("Mark as old"),
        widget=forms.CheckboxSelectMultiple,
        required=False,
    )

    def __init__(self, *args, user: User, club: Club, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["members_old"].queryset = (
            Membership.objects.ongoing().filter(club=club).editable_by(user)
        )


class ClubMemberForm(forms.ModelForm):
    """Form handling the members of a club."""

    error_css_class = "error"
    required_css_class = "required"

    class Meta:
        model = Membership
        fields = ["user", "role", "description"]
        widgets = {"user": AutoCompleteSelectUser}

    def __init__(
        self,
        *args,
        club: Club,
        request_user: User,
        **kwargs,
    ):
        self.club = club
        self.request_user = request_user
        self.request_user_membership = self.club.get_membership_for(self.request_user)
        super().__init__(*args, **kwargs)
        self.fields["role"].required = True
        self.instance.club = club

    def clean_user(self):
        """Check that the user is not trying to add a user already in the club.

        Also check that the user is valid and has a valid subscription.
        """
        user = self.cleaned_data["user"]
        if not user.is_subscribed:
            raise forms.ValidationError(
                _("User must be subscriber to take part to a club"), code="invalid"
            )
        if self.club.get_membership_for(user):
            raise forms.ValidationError(
                _("You can not add the same user twice"), code="invalid"
            )
        return user

    def clean(self):
        """Check user rights for adding an user."""
        cleaned_data = super().clean()
        if "role" not in cleaned_data:
            return cleaned_data
        request_user = self.request_user
        membership = self.request_user_membership
        if not (
            cleaned_data["role"] <= settings.SITH_MAXIMUM_FREE_ROLE
            or (membership is not None and membership.role >= cleaned_data["role"])
            or request_user.has_perm("club.add_subscription")
        ):
            raise forms.ValidationError(_("You do not have the permission to do that"))
        return cleaned_data