# Copyright 2014 Budapest University of Technology and Economics (BME IK)
#
# This file is part of CIRCLE Cloud.
#
# CIRCLE 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.
#
# CIRCLE 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 CIRCLE.  If not, see <http://www.gnu.org/licenses/>.
from __future__ import unicode_literals, absolute_import

import json
import logging

from django.conf import settings
from django.contrib import messages
from django.contrib.auth import login
from django.contrib.auth.models import User, Group
from django.contrib.auth.views import login as login_view
from django.contrib.messages.views import SuccessMessageMixin
from django.core import signing
from django.core.exceptions import (
    PermissionDenied, SuspiciousOperation,
)
from django.core.urlresolvers import reverse, reverse_lazy
from django.core.paginator import Paginator, InvalidPage
from django.db.models import Q
from django.http import HttpResponse, HttpResponseRedirect, Http404
from django.shortcuts import redirect, get_object_or_404
from django.utils.translation import ugettext as _
from django.views.decorators.http import require_POST
from django.views.generic import (
    TemplateView, View, UpdateView, CreateView,
)
from django_sshkey.models import UserKey

from braces.views import LoginRequiredMixin, PermissionRequiredMixin

from django_tables2 import SingleTableView

from vm.models import Instance, InstanceTemplate

from ..forms import (
    CircleAuthenticationForm, MyProfileForm, UserCreationForm, UnsubscribeForm,
    UserKeyForm, CirclePasswordChangeForm, ConnectCommandForm,
    UserListSearchForm, UserEditForm,
)
from ..models import Profile, GroupProfile, ConnectCommand
from ..tables import (
    UserKeyListTable, ConnectCommandListTable, UserListTable,
)

from .util import saml_available, DeleteViewBase


logger = logging.getLogger(__name__)


class NotificationView(LoginRequiredMixin, TemplateView):

    def get_template_names(self):
        if self.request.is_ajax():
            return ['dashboard/_notifications-timeline.html']
        else:
            return ['dashboard/notifications.html']

    def get_context_data(self, *args, **kwargs):
        context = super(NotificationView, self).get_context_data(
            *args, **kwargs)
        paginate_by = 10 if self.request.is_ajax() else 25
        page = self.request.GET.get("page", 1)

        notifications = self.request.user.notification_set.all()
        paginator = Paginator(notifications, paginate_by)
        try:
            current_page = paginator.page(page)
        except InvalidPage:
            current_page = paginator.page(1)

        context['page'] = current_page
        context['paginator'] = paginator
        return context

    def get(self, *args, **kwargs):
        response = super(NotificationView, self).get(*args, **kwargs)
        un = self.request.user.notification_set.filter(status="new")
        for u in un:
            u.status = "read"
            u.save()
        return response


def circle_login(request):
    authentication_form = CircleAuthenticationForm
    extra_context = {
        'saml2': saml_available,
    }
    response = login_view(request, authentication_form=authentication_form,
                          extra_context=extra_context)
    set_language_cookie(request, response)
    return response


class TokenLogin(View):

    token_max_age = 120  # seconds

    @classmethod
    def get_salt(cls):
        return unicode(cls)

    @classmethod
    def get_token(cls, user, sudoer):
        return signing.dumps((sudoer.pk, user.pk),
                             salt=cls.get_salt(), compress=True)

    @classmethod
    def get_token_url(cls, user, sudoer):
        key = cls.get_token(user, sudoer)
        return reverse("dashboard.views.token-login", args=(key, ))

    def get(self, request, token, *args, **kwargs):
        try:
            data = signing.loads(token, salt=self.get_salt(),
                                 max_age=self.token_max_age)
            logger.debug('TokenLogin token data: %s', unicode(data))
            sudoer, user = data
            logger.debug('Extracted TokenLogin data: sudoer: %s, user: %s',
                         unicode(sudoer), unicode(user))
        except (signing.BadSignature, ValueError, TypeError) as e:
            logger.warning('Tried invalid TokenLogin token. '
                           'Token: %s, user: %s. %s',
                           token, unicode(self.request.user), unicode(e))
            raise SuspiciousOperation()
        sudoer = User.objects.get(pk=sudoer)
        if not sudoer.is_superuser:
            raise PermissionDenied()
        user = User.objects.get(pk=user)
        user.backend = 'django.contrib.auth.backends.ModelBackend'
        logger.warning('%s %d logged in as user %s %d',
                       unicode(sudoer), sudoer.pk, unicode(user), user.pk)
        login(request, user)
        messages.info(request, _("Logged in as user %s.") % unicode(user))
        return redirect("/")


class MyPreferencesView(UpdateView):
    model = Profile

    def get_context_data(self, *args, **kwargs):
        context = super(MyPreferencesView, self).get_context_data(*args,
                                                                  **kwargs)
        context['forms'] = {
            'change_password': CirclePasswordChangeForm(
                user=self.request.user),
            'change_language': MyProfileForm(instance=self.get_object()),
        }
        key_table = UserKeyListTable(
            UserKey.objects.filter(user=self.request.user),
            request=self.request)
        key_table.page = None
        context['userkey_table'] = key_table
        cmd_table = ConnectCommandListTable(
            self.request.user.command_set.all(),
            request=self.request)
        cmd_table.page = None
        context['connectcommand_table'] = cmd_table
        return context

    def get_object(self, queryset=None):
        if self.request.user.is_anonymous():
            raise PermissionDenied()
        try:
            return self.request.user.profile
        except Profile.DoesNotExist:
            raise Http404(_("You don't have a profile."))

    def post(self, request, *args, **kwargs):
        self.ojbect = self.get_object()
        redirect_response = HttpResponseRedirect(
            reverse("dashboard.views.profile-preferences"))
        if "preferred_language" in request.POST:
            form = MyProfileForm(request.POST, instance=self.get_object())
            if form.is_valid():
                lang = form.cleaned_data.get("preferred_language")
                set_language_cookie(self.request, redirect_response, lang)
                form.save()
        else:
            form = CirclePasswordChangeForm(user=request.user,
                                            data=request.POST)
            if form.is_valid():
                form.save()

        if form.is_valid():
            return redirect_response
        else:
            return self.get(request, form=form, *args, **kwargs)

    def get(self, request, form=None, *args, **kwargs):
        # if this is not here, it won't work
        self.object = self.get_object()
        context = self.get_context_data(*args, **kwargs)
        if form is not None:
            # a little cheating, users can't post invalid
            # language selection forms (without modifying the HTML)
            context['forms']['change_password'] = form
        return self.render_to_response(context)


class UnsubscribeFormView(SuccessMessageMixin, UpdateView):
    model = Profile
    form_class = UnsubscribeForm
    template_name = "dashboard/unsubscribe.html"
    success_message = _("Successfully modified subscription.")

    def get_success_url(self):
        if self.request.user.is_authenticated():
            return super(UnsubscribeFormView, self).get_success_url()
        else:
            return self.request.path

    @classmethod
    def get_salt(cls):
        return unicode(cls)

    @classmethod
    def get_token(cls, user):
        return signing.dumps(user.pk, salt=cls.get_salt(), compress=True)

    def get_object(self, queryset=None):
        key = self.kwargs['token']
        try:
            pk = signing.loads(key, salt=self.get_salt(), max_age=48 * 3600)
        except signing.SignatureExpired:
            raise
        except (signing.BadSignature, ValueError, TypeError) as e:
            logger.warning('Tried invalid token. Token: %s, user: %s. %s',
                           key, unicode(self.request.user), unicode(e))
            raise Http404
        else:
            return (queryset or self.get_queryset()).get(user_id=pk)

    def dispatch(self, request, *args, **kwargs):
        try:
            return super(UnsubscribeFormView, self).dispatch(
                request, *args, **kwargs)
        except signing.SignatureExpired:
            return redirect('dashboard.views.profile-preferences')


def set_language_cookie(request, response, lang=None):
    if lang is None:
        try:
            lang = request.user.profile.preferred_language
        except:
            return

    cname = getattr(settings, 'LANGUAGE_COOKIE_NAME', 'django_language')
    response.set_cookie(cname, lang, 365 * 86400)


class UserCreationView(LoginRequiredMixin, PermissionRequiredMixin,
                       CreateView):
    form_class = UserCreationForm
    model = User
    template_name = 'dashboard/user-create.html'
    permission_required = "auth.add_user"

    def get_template_names(self):
        return ['dashboard/nojs-wrapper.html']

    def get_context_data(self, *args, **kwargs):
        context = super(UserCreationView, self).get_context_data(*args,
                                                                 **kwargs)
        context.update({
            'template': self.template_name,
            'box_title': _('Create a User'),
        })
        return context

    def get_success_url(self):
        return reverse('dashboard.views.profile', args=[self.object.username])

    def get_form_kwargs(self):
        profiles = GroupProfile.get_objects_with_level(
            'owner', self.request.user)
        choices = Group.objects.filter(groupprofile__in=profiles)
        group_pk = self.request.GET.get('group_pk')
        if group_pk:
            try:
                default = choices.get(pk=group_pk)
            except (ValueError, Group.DoesNotExist):
                raise Http404()
        else:
            default = None

        val = super(UserCreationView, self).get_form_kwargs()
        val.update({'choices': choices, 'default': default})
        return val


class ProfileView(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    template_name = "dashboard/profile.html"
    model = User
    slug_field = "username"
    slug_url_kwarg = "username"
    form_class = UserEditForm
    success_message = _("Successfully modified user.")

    def get(self, *args, **kwargs):
        user = self.request.user
        target = self.get_object()

        # get the list of groups where the user is operator
        user_g_w_op = GroupProfile.get_objects_with_level("operator", user)
        # get the list of groups the "target" (the profile) is member of
        target_groups = GroupProfile.objects.filter(
            group__in=target.groups.all())
        intersection = set(user_g_w_op).intersection(target_groups)

        # if the intersection of the 2 lists is empty the logged in user
        # has no permission to check the target's profile
        # (except if the user want to see his own profile)
        if not intersection and target != user and not user.is_superuser:
            raise PermissionDenied

        return super(ProfileView, self).get(*args, **kwargs)

    def get_context_data(self, **kwargs):
        context = super(ProfileView, self).get_context_data(**kwargs)
        user = self.get_object()
        context['profile'] = user
        context['avatar_url'] = user.profile.get_avatar_url()
        context['instances_owned'] = Instance.get_objects_with_level(
            "owner", user, disregard_superuser=True).filter(destroyed_at=None)
        context['instances_with_access'] = Instance.get_objects_with_level(
            "user", user, disregard_superuser=True
        ).filter(destroyed_at=None).exclude(pk__in=context['instances_owned'])

        group_profiles = GroupProfile.get_objects_with_level(
            "operator", self.request.user)
        groups = Group.objects.filter(groupprofile__in=group_profiles)
        context['groups'] = user.groups.filter(pk__in=groups)

        # permissions
        # show groups only if the user is superuser, or have access
        # to any of the groups the user belongs to
        context['perm_group_list'] = (
            self.request.user.is_superuser or len(context['groups']) > 0)
        context['perm_email'] = (
            context['perm_group_list'] or self.request.user == user)

        # filter the virtual machine list
        # if the logged in user is not superuser or not the user itself
        # filter the list so only those virtual machines are shown that are
        # originated from templates the logged in user is operator or higher
        if not (self.request.user.is_superuser or self.request.user == user):
            it = InstanceTemplate.get_objects_with_level("operator",
                                                         self.request.user)
            context['instances_owned'] = context['instances_owned'].filter(
                template__in=it)
            context['instances_with_access'] = context[
                'instances_with_access'].filter(template__in=it)
        if self.request.user.is_superuser:
            context['login_token'] = TokenLogin.get_token_url(
                user, self.request.user)
        return context

    def post(self, request, *args, **kwargs):
        if not request.user.has_perm('auth.change_user'):
            raise PermissionDenied()
        return super(ProfileView, self).post(self, request, *args, **kwargs)

    def get_success_url(self):
        return reverse('dashboard.views.profile',
                       kwargs=self.kwargs)


@require_POST
def toggle_use_gravatar(request, **kwargs):
    user = get_object_or_404(User, username=kwargs['username'])
    if not request.user == user:
        raise PermissionDenied()

    profile = user.profile
    profile.use_gravatar = not profile.use_gravatar
    profile.save()

    new_avatar_url = user.profile.get_avatar_url()
    return HttpResponse(
        json.dumps({'new_avatar_url': new_avatar_url}),
        content_type="application/json",
    )


class UserKeyDetail(LoginRequiredMixin, SuccessMessageMixin, UpdateView):
    model = UserKey
    template_name = "dashboard/userkey-edit.html"
    form_class = UserKeyForm
    success_message = _("Successfully modified SSH key.")

    def get(self, request, *args, **kwargs):
        object = self.get_object()
        if object.user != request.user:
            raise PermissionDenied()
        return super(UserKeyDetail, self).get(request, *args, **kwargs)

    def get_success_url(self):
        return reverse_lazy("dashboard.views.userkey-detail",
                            kwargs=self.kwargs)

    def post(self, request, *args, **kwargs):
        object = self.get_object()
        if object.user != request.user:
            raise PermissionDenied()
        return super(UserKeyDetail, self).post(self, request, args, kwargs)


class UserKeyDelete(DeleteViewBase):
    model = UserKey
    success_message = _("SSH key successfully deleted.")

    def get_success_url(self):
        return reverse("dashboard.views.profile-preferences")

    def check_auth(self):
        if self.get_object().user != self.request.user:
            raise PermissionDenied()


class UserKeyCreate(LoginRequiredMixin, SuccessMessageMixin, CreateView):
    model = UserKey
    form_class = UserKeyForm
    template_name = "dashboard/userkey-create.html"
    success_message = _("Successfully created a new SSH key.")

    def get_success_url(self):
        return reverse_lazy("dashboard.views.profile-preferences")

    def get_form_kwargs(self):
        kwargs = super(UserKeyCreate, self).get_form_kwargs()
        kwargs['user'] = self.request.user
        return kwargs


class ConnectCommandDetail(LoginRequiredMixin, SuccessMessageMixin,
                           UpdateView):
    model = ConnectCommand
    template_name = "dashboard/connect-command-edit.html"
    form_class = ConnectCommandForm
    success_message = _("Successfully modified command template.")

    def get(self, request, *args, **kwargs):
        object = self.get_object()
        if object.user != request.user:
            raise PermissionDenied()
        return super(ConnectCommandDetail, self).get(request, *args, **kwargs)

    def get_success_url(self):
        return reverse_lazy("dashboard.views.connect-command-detail",
                            kwargs=self.kwargs)

    def post(self, request, *args, **kwargs):
        object = self.get_object()
        if object.user != request.user:
            raise PermissionDenied()
        return super(ConnectCommandDetail, self).post(request, args, kwargs)

    def get_form_kwargs(self):
        kwargs = super(ConnectCommandDetail, self).get_form_kwargs()
        kwargs['user'] = self.request.user
        return kwargs


class ConnectCommandDelete(DeleteViewBase):
    model = ConnectCommand
    success_message = _("Command template successfully deleted.")

    def get_success_url(self):
        return reverse("dashboard.views.profile-preferences")

    def check_auth(self):
        if self.get_object().user != self.request.user:
            raise PermissionDenied()


class ConnectCommandCreate(LoginRequiredMixin, SuccessMessageMixin,
                           CreateView):
    model = ConnectCommand
    form_class = ConnectCommandForm
    template_name = "dashboard/connect-command-create.html"
    success_message = _("Successfully created a new command template.")

    def get_success_url(self):
        return reverse_lazy("dashboard.views.profile-preferences")

    def get_form_kwargs(self):
        kwargs = super(ConnectCommandCreate, self).get_form_kwargs()
        kwargs['user'] = self.request.user
        return kwargs


class UserList(LoginRequiredMixin, PermissionRequiredMixin, SingleTableView):
    template_name = "dashboard/user-list.html"
    permission_required = "auth.change_user"
    model = User
    table_class = UserListTable
    table_pagination = True

    def get_context_data(self, *args, **kwargs):
        context = super(UserList, self).get_context_data(*args, **kwargs)
        context['search_form'] = self.search_form
        return context

    def get(self, *args, **kwargs):
        self.search_form = UserListSearchForm(self.request.GET)
        self.search_form.full_clean()

        if self.request.is_ajax():
            users = [
                {'url': reverse("dashboard.views.profile", args=[i.username]),
                 'name': i.get_full_name() or i.username,
                 'org_id': i.profile.org_id,
                 }
                for i in self.get_queryset()]
            return HttpResponse(
                json.dumps(users), content_type="application/json")
        else:
            return super(UserList, self).get(*args, **kwargs)

    def get_queryset(self):
        logger.debug('UserList.get_queryset() called. User: %s',
                     unicode(self.request.user))
        qs = User.objects.all().order_by("-pk")

        q = self.search_form.cleaned_data.get('s')
        if q:
            filters = (Q(username__icontains=q) | Q(email__icontains=q)
                       | Q(profile__org_id__icontains=q))
            for w in q.split()[:3]:
                filters |= (
                    Q(first_name__icontains=w) | Q(last_name__icontains=w))
            qs = qs.filter(filters)

        return qs.select_related("profile")