# Copyright 2012 Nebula, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from importlib import import_module
import logging
import urllib

from django.conf import settings
from django import http
from django import shortcuts
from django import urls
from django.utils.encoding import smart_text
import django.views.decorators.vary
from django.views.generic import TemplateView

import horizon
from horizon import exceptions
from horizon import notifications

LOG = logging.getLogger(__name__)


MESSAGES_PATH = settings.MESSAGES_PATH


def get_user_home(user):
    dashboard = horizon.get_default_dashboard()
    return dashboard.get_absolute_url()


# TODO(stephenfin): Migrate to CBV
@django.views.decorators.vary.vary_on_cookie
def splash(request):
    if not request.user.is_authenticated:
        raise exceptions.NotAuthenticated()

    response = shortcuts.redirect(horizon.get_user_home(request.user))
    if 'logout_reason' in request.COOKIES:
        response.delete_cookie('logout_reason')
    if 'logout_status' in request.COOKIES:
        response.delete_cookie('logout_status')
    # Display Message of the Day message from the message files
    # located in MESSAGES_PATH
    if MESSAGES_PATH:
        notifications.process_message_notification(request, MESSAGES_PATH)
    return response


def get_url_with_pagination(request, marker_name, prev_marker_name, url_string,
                            object_id=None):
    if object_id:
        url = urls.reverse(url_string, args=(object_id,))
    else:
        url = urls.reverse(url_string)
    marker = request.GET.get(marker_name, None)
    if marker:
        return "{}?{}".format(url,
                              urllib.parse.urlencode({marker_name: marker}))

    prev_marker = request.GET.get(prev_marker_name, None)
    if prev_marker:
        return "{}?{}".format(url,
                              urllib.parse.urlencode({prev_marker_name:
                                                      prev_marker}))
    return url


class ExtensibleHeaderView(TemplateView):
    template_name = 'header/_header_sections.html'

    def get_context_data(self, **kwargs):
        context = super(ExtensibleHeaderView, self).get_context_data(**kwargs)
        header_sections = []
        config = getattr(settings, 'HORIZON_CONFIG', {})
        for view_path in config.get("header_sections", []):
            mod_path, view_cls = view_path.rsplit(".", 1)
            try:
                mod = import_module(mod_path)
            except ImportError:
                LOG.warning("Could not load header view: %s", mod_path)
                continue

            try:
                view = getattr(mod, view_cls)(request=self.request)
                response = view.get(self.request)
                rendered_response = response.render()
                packed_response = [view_path.replace('.', '-'),
                                   smart_text(rendered_response.content)]
                header_sections.append(packed_response)

            except Exception as e:
                LOG.warning("Could not render header %(path)s, exception: "
                            "%(exc)s", {'path': view_path, 'exc': e})
                continue

        context['header_sections'] = header_sections
        return context


def csrf_failure(request, reason=""):
    url = settings.LOGIN_URL + "?csrf_failure=%s" % urllib.parse.quote(reason)
    response = http.HttpResponseRedirect(url)
    return response
