# -*- coding: utf-8 -*-
# Copyright (C) 1998-2021 by the Free Software Foundation, Inc.
#
# This file is part of Postorius.
#
# Postorius is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# Postorius 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
# Postorius.  If not, see <http://www.gnu.org/licenses/>.


import logging
from urllib.error import HTTPError

from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.contrib.auth.forms import AdminPasswordChangeForm
from django.forms import formset_factory
from django.http import Http404
from django.shortcuts import render
from django.urls import reverse, reverse_lazy
from django.utils.decorators import method_decorator
from django.utils.translation import gettext as _
from django.views.decorators.debug import sensitive_post_parameters
from django.views.decorators.http import require_GET
from django.views.generic import FormView

from allauth.account.models import EmailAddress
from django_mailman3.lib.mailman import get_mailman_client, get_mailman_user
from django_mailman3.lib.paginator import MailmanPaginator, paginate

from postorius.auth.decorators import superuser_required
from postorius.forms import (
    ChangeSubscriptionForm, ManageAddressForm, ManageAddressFormSet,
    ManageMemberForm, ManageMemberFormSet, ManageUserForm, UserPreferences,
    UserPreferencesFormset)
from postorius.models import List, SubscriptionMode
from postorius.utils import (
    filter_memberships_by_roles, get_django_user, set_preferred)
from postorius.views.generic import MailmanClientMixin


logger = logging.getLogger(__name__)


class UserPreferencesView(FormView, MailmanClientMixin):
    """Generic view for the logged-in user's various preferences."""

    form_class = UserPreferences

    #: Disabled delivery_status choices that a subscriber cannot set. This is
    #: different from what an admi is allowed to set.
    delivery_status_disabled_fields = ['by_moderator', 'by_bounces']

    def get_context_data(self, **kwargs):
        data = super(UserPreferencesView, self).get_context_data(**kwargs)
        data['mm_user'] = self.mm_user
        return data

    def get_form_kwargs(self):
        kwargs = super(UserPreferencesView, self).get_form_kwargs()
        kwargs['preferences'] = self._get_preferences()
        # Disable the choice of by_admin and by_bounces for a user.
        kwargs[
            'disabled_delivery_choices'] = self.delivery_status_disabled_fields
        return kwargs

    def _set_view_attributes(self, request, *args, **kwargs):
        self.mm_user = get_mailman_user(request.user)

    @method_decorator(login_required)
    def dispatch(self, request, *args, **kwargs):
        self._set_view_attributes(request, *args, **kwargs)
        return super(UserPreferencesView, self).dispatch(
            request, *args, **kwargs)

    def form_valid(self, form):
        try:
            form.save()
        except HTTPError as e:
            messages.error(self.request, e.msg)
        if form.has_changed():
            messages.success(
                self.request, _('Your preferences have been updated.'))
        else:
            messages.info(self.request, _('Your preferences did not change.'))
        return super(UserPreferencesView, self).form_valid(form)


class UserMailmanSettingsView(UserPreferencesView):
    """The logged-in user's global Mailman preferences."""

    form_class = UserPreferences
    template_name = 'postorius/user/mailman_settings.html'
    success_url = reverse_lazy('user_mailmansettings')

    def _get_preferences(self):
        # Get the defaults and pre-populate so view shows them
        combinedpreferences = self._get_combined_preferences()
        for key in combinedpreferences:
            if key != "self_link":
                self.mm_user.preferences[key] = combinedpreferences[key]

        # This is a bit of a hack so preferences behave as users expect
        # We probably don't want to save, only display here
        # but this means that whatever preferences the users see first are
        # the ones they have unless they explicitly change them
        self.mm_user.preferences.save()

        return self.mm_user.preferences

    def _get_combined_preferences(self):
        # Get layers of default preferences to match how they are applied
        # We ignore self_link as we don't want to over-write it
        defaultpreferences = get_mailman_client().preferences
        combinedpreferences = {}
        for key in defaultpreferences:
            if key != "self_link":
                combinedpreferences[key] = defaultpreferences[key]

        # Clobber defaults with any preferences already set
        for key in self.mm_user.preferences:
            if key != "self_link":
                combinedpreferences[key] = self.mm_user.preferences[key]

        return(combinedpreferences)


class UserAddressPreferencesView(UserPreferencesView):
    """The logged-in user's address-based Mailman Preferences."""

    template_name = 'postorius/user/address_preferences.html'
    success_url = reverse_lazy('user_address_preferences')

    def get_form_class(self):
        return formset_factory(
            UserPreferences, formset=UserPreferencesFormset, extra=0)

    def _get_preferences(self):
        return [address.preferences for address in self.mm_user.addresses]

    def _get_combined_preferences(self):
        # grab the default preferences
        defaultpreferences = get_mailman_client().preferences

        # grab your global preferences
        globalpreferences = self.mm_user.preferences

        # start a new combined preferences object
        combinedpreferences = []

        for address in self.mm_user.addresses:
            # make a per-address prefs object
            prefs = {}

            # initialize with default preferences
            for key in defaultpreferences:
                if key != "self_link":
                    prefs[key] = defaultpreferences[key]

            # overwrite with user's global preferences
            for key in globalpreferences:
                if key != "self_link":
                    prefs[key] = globalpreferences[key]

            # overwrite with address-specific preferences
            for key in address.preferences:
                if key != "self_link":
                    prefs[key] = address.preferences[key]
            combinedpreferences.append(prefs)

            # put the combined preferences back on the original object
            for key in prefs:
                if key != "self_link":
                    address.preferences[key] = prefs[key]

        return combinedpreferences

    def get_context_data(self, **kwargs):
        data = super(UserAddressPreferencesView, self).get_context_data(
            **kwargs)
        data['formset'] = data.pop('form')
        for form, address in list(zip(
                data['formset'].forms, self.mm_user.addresses)):
            form.address = address
        return data


class UserListOptionsView(UserPreferencesView):
    """The logged-in user's subscription preferences."""

    form_class = UserPreferences
    template_name = 'postorius/user/list_options.html'

    def _get_subscription(self, member_id):
        subscription = None
        # We *could* use the find_members API, but then we'd have to
        # authenticate that the found subscription belongs to the currently
        # logged-in user otherwise. That might be a faster choice, but this
        # page isn't that slow right now.
        for s in self.mm_user.subscriptions:
            if s.role == 'member' and s.member_id == member_id:
                subscription = s
                break
        if not subscription:
            raise Http404(_('Subscription does not exist'))
        return subscription

    def _set_view_attributes(self, request, *args, **kwargs):
        super(UserListOptionsView, self)._set_view_attributes(
            request, *args, **kwargs)
        self.member_id = kwargs.get('member_id')
        self.subscription = self._get_subscription(self.member_id)
        self.mlist = List.objects.get_or_404(
            fqdn_listname=self.subscription.list_id)
        if (self.subscription.subscription_mode ==
                SubscriptionMode.as_user.name):
            self.subscriber = self.subscription.user.user_id
        else:
            self.subscriber = self.subscription.email

    def _get_preferences(self):
        return self.subscription.preferences

    def get_context_data(self, **kwargs):
        data = super(UserListOptionsView, self).get_context_data(**kwargs)
        data['mlist'] = self.mlist
        user_emails = EmailAddress.objects.filter(
            user=self.request.user, verified=True).order_by(
            "email").values_list("email", flat=True)
        mm_user = get_mailman_user(self.request.user)
        primary_email = None
        if mm_user.preferred_address is None:
            primary_email = set_preferred(self.request.user, mm_user)
        else:
            primary_email = mm_user.preferred_address.email
        data['change_subscription_form'] = ChangeSubscriptionForm(
            user_emails, mm_user.user_id, primary_email,
            initial={'subscriber': self.subscriber,
                     'member_id': self.member_id})
        return data

    def get_success_url(self):
        return reverse(
            'user_list_options', kwargs=dict(member_id=self.member_id))


class UserSubscriptionPreferencesView(UserPreferencesView):
    """The logged-in user's subscription-based Mailman Preferences."""

    template_name = 'postorius/user/subscription_preferences.html'
    success_url = reverse_lazy('user_subscription_preferences')

    def _get_subscriptions(self):
        subscriptions = []
        for s in self.mm_user.subscriptions:
            if s.role != 'member':
                continue
            subscriptions.append(s)
        return subscriptions

    def _set_view_attributes(self, request, *args, **kwargs):
        super(UserSubscriptionPreferencesView, self)._set_view_attributes(
            request, *args, **kwargs)
        self.subscriptions = self._get_subscriptions()

    def get_form_class(self):
        return formset_factory(
            UserPreferences, formset=UserPreferencesFormset, extra=0)

    def _get_preferences(self):
        return [sub.preferences for sub in self.subscriptions]

    def _get_combined_preferences(self):
        # grab the default preferences
        defaultpreferences = get_mailman_client().preferences

        # grab your global preferences
        globalpreferences = self.mm_user.preferences

        # start a new combined preferences object
        combinedpreferences = []

        for sub in self.subscriptions:
            # make a per-address prefs object
            prefs = {}

            # initialize with default preferences
            for key in defaultpreferences:
                if key != "self_link":
                    prefs[key] = defaultpreferences[key]

            # overwrite with user's global preferences
            for key in globalpreferences:
                if key != "self_link":
                    prefs[key] = globalpreferences[key]

            # overwrite with address-based preferences
            # There is currently no better way to do this,
            # we may consider revisiting.
            addresspreferences = {}
            for address in self.mm_user.addresses:
                if sub.email == address.email:
                    addresspreferences = address.preferences

            for key in addresspreferences:
                if key != "self_link":
                    prefs[key] = addresspreferences[key]

            # overwrite with subscription-specific preferences
            for key in sub.preferences:
                if key != "self_link":
                    prefs[key] = sub.preferences[key]

            combinedpreferences.append(prefs)

        return combinedpreferences
        # return [sub.preferences for sub in self.subscriptions]

    def get_context_data(self, **kwargs):
        data = super(UserSubscriptionPreferencesView, self).get_context_data(
            **kwargs)
        data['formset'] = data.pop('form')
        for form, subscription in list(zip(
                data['formset'].forms, self.subscriptions)):
            form.list_id = subscription.list_id
            form.member_id = subscription.member_id
            form.subscription_mode = subscription.subscription_mode
            form.address = subscription.address
        return data


@login_required
def user_subscriptions(request):
    """Shows the subscriptions of a user."""
    mm_user = get_mailman_user(request.user)
    memberships = [m for m in mm_user.subscriptions]
    return render(request, 'postorius/user/subscriptions.html',
                  {'memberships': memberships})


@require_GET
@superuser_required
def list_users(request):
    """List of all users."""
    client = get_mailman_client()
    query = request.GET.get('q')

    if query:
        def _find_users(count, page):
            return client.find_users_page(query, count, page)
        find_method = _find_users
    else:
        find_method = client.get_user_page

    users = paginate(find_method,
                     request.GET.get('page'),
                     request.GET.get('count'),
                     paginator_class=MailmanPaginator)
    return render(request,
                  'postorius/user/all.html',
                  {'all_users': users, 'query': query})


@superuser_required
@sensitive_post_parameters('password1', 'password2')
def manage_user(request, user_id):
    """Manage a single Mailman user view."""
    client = get_mailman_client()
    user = client.get_user(user_id)
    user_form = ManageUserForm(user=user)
    addr_formset = formset_factory(
        ManageAddressForm, formset=ManageAddressFormSet, extra=0)
    sub_formset = formset_factory(
        ManageMemberForm, formset=ManageMemberFormSet, extra=0)
    django_user = get_django_user(user)
    addresses = addr_formset(addresses=user.addresses)
    subscriptions = sub_formset(members=filter_memberships_by_roles(
        user.subscriptions, roles=['member', 'nonmember']))

    change_password = None
    if django_user is not None:
        change_password = AdminPasswordChangeForm(django_user)
        # The form always grabs focus so stop it from doing that unless there
        # is an error in the form submitted.
        change_password.fields['password1'].widget.attrs['autofocus'] = False

    if request.method == 'POST':
        # There are 4 forms in this view page, which one was submitted is
        # distinguished based on the name of the submit button.
        if 'address_form' in request.POST:
            # This is the 'addresses' form, built using addr_formset.
            addresses = addr_formset(request.POST, addresses=user.addresses)
            if addresses.is_valid():
                updated = addresses.save()
                if updated:
                    messages.success(
                        request,
                        _('Successfully updated addresses {}').format(', '.join(updated)))     # noqa: E501
        elif 'subs_form' in request.POST:
            # This is the 'subscriptions' form, built using sub_formset.
            subscriptions = sub_formset(
                request.POST, members=user.subscriptions)
            if subscriptions.is_valid():
                updated = subscriptions.save()
                if updated:
                    messages.success(
                        request,
                        _('Successfully updated memberships for {}').format(', '.join(updated)))  # noqa: E501
        elif 'user_form' in request.POST:
            # This is the 'user' form, built using ManageUserForm.
            user_form = ManageUserForm(request.POST, user=user)
            if user_form.is_valid():
                user_form.save()
                messages.success(request, _('Successfully updated user.'))
        elif 'change_password' in request.POST:
            change_password = AdminPasswordChangeForm(
                django_user, request.POST)
            if change_password.is_valid():
                change_password.save()
                # This will log the user out, which we want because the admin
                # is changing their password. In case of user changing their
                # own passowrd, they can remain authenticated.
                messages.success(request, _('Password updated successfully'))
                # Stop the form from grabbing the passowrd if successfully
                # updated.
                change_password.fields[
                    'password1'].widget.attrs['autofocus'] = False

    return render(request,
                  'postorius/user/manage.html',
                  {'auser': user,
                   'user_form': user_form,
                   'change_password': change_password,
                   'django_user': django_user,
                   'addresses': addresses,
                   'subscriptions': subscriptions})
