# -*- coding: utf-8 -*-
from django.contrib import messages
from django.contrib.auth import update_session_auth_hash
from django.contrib.auth.forms import PasswordChangeForm
from django.contrib.auth.models import User
from django.contrib.auth.views import LogoutView as LogoutViewBase
from django.contrib.messages.views import SuccessMessageMixin
from django.shortcuts import redirect, render
from django.urls import reverse, reverse_lazy
from django.utils import translation
from django.utils.decorators import method_decorator
from django.utils.text import format_lazy
from django.utils.translation import gettext as _, gettext_lazy
from django.views.decorators.cache import never_cache
from django.views.decorators.csrf import csrf_protect
from django.views.decorators.http import require_POST
from django.views.generic import View
from django.views.generic.base import TemplateView, RedirectView
from django.views.generic.edit import CreateView, UpdateView, DeleteView
from django.views.i18n import set_language

from django_filters.views import FilterView

from babybuddy import forms
from babybuddy.mixins import LoginRequiredMixin, PermissionRequiredMixin, \
    StaffOnlyMixin


class RootRouter(LoginRequiredMixin, RedirectView):
    """
    Redirects to the site dashboard.
    """
    def get_redirect_url(self, *args, **kwargs):
        self.url = reverse('dashboard:dashboard')
        return super(RootRouter, self).get_redirect_url(self, *args, **kwargs)


class BabyBuddyFilterView(FilterView):
    """
    Disables "strictness" for django-filter. It is unclear from the
    documentation exactly what this does...
    """
    # TODO Figure out the correct way to use this.
    strict = False

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        children = {
            o.child for o in context['object_list'] if hasattr(o, "child")
        }
        if len(children) == 1:
            context['unique_child'] = True
        return context


@method_decorator(csrf_protect, name='dispatch')
@method_decorator(never_cache, name='dispatch')
@method_decorator(require_POST, name='dispatch')
class LogoutView(LogoutViewBase):
    pass


class UserList(StaffOnlyMixin, BabyBuddyFilterView):
    model = User
    template_name = 'babybuddy/user_list.html'
    ordering = 'username'
    paginate_by = 10
    filterset_fields = ('username', 'first_name', 'last_name', 'email')


class UserAdd(StaffOnlyMixin, PermissionRequiredMixin, SuccessMessageMixin,
              CreateView):
    model = User
    template_name = 'babybuddy/user_form.html'
    permission_required = ('admin.add_user',)
    form_class = forms.UserAddForm
    success_url = reverse_lazy('babybuddy:user-list')
    success_message = gettext_lazy('User %(username)s added!')


class UserUpdate(StaffOnlyMixin, PermissionRequiredMixin,
                 SuccessMessageMixin, UpdateView):
    model = User
    template_name = 'babybuddy/user_form.html'
    permission_required = ('admin.change_user',)
    form_class = forms.UserUpdateForm
    success_url = reverse_lazy('babybuddy:user-list')
    success_message = gettext_lazy('User %(username)s updated.')


class UserDelete(StaffOnlyMixin, PermissionRequiredMixin,
                 DeleteView, SuccessMessageMixin):
    model = User
    template_name = 'babybuddy/user_confirm_delete.html'
    permission_required = ('admin.delete_user',)
    success_url = reverse_lazy('babybuddy:user-list')

    def get_success_message(self, cleaned_data):
        return format_lazy(gettext_lazy(
            'User {user} deleted.'), user=self.get_object()
        )


class UserPassword(LoginRequiredMixin, View):
    """
    Handles user password changes.
    """
    form_class = forms.UserPasswordForm
    template_name = 'babybuddy/user_password_form.html'

    def get(self, request):
        return render(request, self.template_name, {
            'form': self.form_class(request.user)
        })

    def post(self, request):
        form = PasswordChangeForm(request.user, request.POST)
        if form.is_valid():
            user = form.save()
            update_session_auth_hash(request, user)
            messages.success(request, _('Password updated.'))
        return render(request, self.template_name, {'form': form})


class UserSettings(LoginRequiredMixin, View):
    """
    Handles both the User and Settings models.
    Based on this SO answer: https://stackoverflow.com/a/45056835.
    """
    form_user_class = forms.UserForm
    form_settings_class = forms.UserSettingsForm
    template_name = 'babybuddy/user_settings_form.html'

    def get(self, request):
        return render(request, self.template_name, {
            'form_user': self.form_user_class(instance=request.user),
            'form_settings': self.form_settings_class(
                instance=request.user.settings)
        })

    def post(self, request):
        if request.POST.get('api_key_regenerate'):
            request.user.settings.api_key(reset=True)
            messages.success(request, _('User API key regenerated.'))
            return redirect('babybuddy:user-settings')

        form_user = self.form_user_class(
            instance=request.user,
            data=request.POST)
        form_settings = self.form_settings_class(
            instance=request.user.settings,
            data=request.POST)
        if form_user.is_valid() and form_settings.is_valid():
            user = form_user.save(commit=False)
            user_settings = form_settings.save(commit=False)
            user.settings = user_settings
            user.save()
            translation.activate(user.settings.language)
            messages.success(request, _('Settings saved!'))
            translation.deactivate()
            return set_language(request)
        return render(request, self.template_name, {
            'user_form': form_user,
            'settings_form': form_settings
        })


class Welcome(LoginRequiredMixin, TemplateView):
    """
    Basic introduction to Baby Buddy (meant to be shown when no data is in the
    database).
    """
    template_name = 'babybuddy/welcome.html'