#
# This file is part of FreedomBox.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
"""
Views for the dynamicsdns module.
"""

import logging

from django.contrib import messages
from django.template.response import TemplateResponse
from django.urls import reverse_lazy
from django.utils.translation import ugettext as _
from django.utils.translation import ugettext_lazy

from plinth import actions
from plinth.modules import dynamicdns
from plinth.signals import domain_added, domain_removed

from .forms import ConfigureForm

logger = logging.getLogger(__name__)

EMPTYSTRING = 'none'

subsubmenu = [{
    'url': reverse_lazy('dynamicdns:index'),
    'text': ugettext_lazy('About')
}, {
    'url': reverse_lazy('dynamicdns:configure'),
    'text': ugettext_lazy('Configure')
}, {
    'url': reverse_lazy('dynamicdns:statuspage'),
    'text': ugettext_lazy('Status')
}]


def index(request):
    """Serve Dynamic DNS page."""
    return TemplateResponse(
        request, 'dynamicdns.html', {
            'title': dynamicdns.name,
            'name': dynamicdns.name,
            'description': dynamicdns.description,
            'manual_page': dynamicdns.manual_page,
            'subsubmenu': subsubmenu
        })


def configure(request):
    """Serve the configuration form."""
    status = dynamicdns.get_status()
    form = None

    if request.method == 'POST':
        form = ConfigureForm(request.POST, initial=status)
        if form.is_valid():
            _apply_changes(request, status, form.cleaned_data)
            status = dynamicdns.get_status()
            form = ConfigureForm(initial=status)
    else:
        form = ConfigureForm(initial=status)

    return TemplateResponse(
        request, 'dynamicdns_configure.html', {
            'title': _('Configure Dynamic DNS'),
            'name': dynamicdns.name,
            'description': dynamicdns.description,
            'manual_page': dynamicdns.manual_page,
            'form': form,
            'subsubmenu': subsubmenu
        })


def statuspage(request):
    """Serve the status page."""
    check_nat = _run(['get-nat'])
    last_update = _run(['get-last-success'])

    no_nat = check_nat.strip() == 'no'
    nat_unchecked = check_nat.strip() == 'unknown'
    timer = _run(['get-timer'])

    if no_nat:
        logger.info('Not behind a NAT')

    if nat_unchecked:
        logger.info('Did not check if behind a NAT')

    return TemplateResponse(
        request, 'dynamicdns_status.html', {
            'title': _('Dynamic DNS Status'),
            'name': dynamicdns.name,
            'description': dynamicdns.description,
            'manual_page': dynamicdns.manual_page,
            'no_nat': no_nat,
            'nat_unchecked': nat_unchecked,
            'timer': timer,
            'last_update': last_update,
            'subsubmenu': subsubmenu
        })


def _apply_changes(request, old_status, new_status):
    """Apply the changes to Dynamic DNS client."""
    logger.info('New status is - %s', new_status)
    logger.info('Old status was - %s', old_status)

    if new_status['dynamicdns_secret'] == '':
        new_status['dynamicdns_secret'] = old_status['dynamicdns_secret']

    if new_status['dynamicdns_ipurl'] == '':
        new_status['dynamicdns_ipurl'] = EMPTYSTRING

    if new_status['dynamicdns_update_url'] == '':
        new_status['dynamicdns_update_url'] = EMPTYSTRING

    if new_status['dynamicdns_server'] == '':
        new_status['dynamicdns_server'] = EMPTYSTRING

    if new_status['service_type'] == 'GnuDIP':
        new_status['dynamicdns_update_url'] = EMPTYSTRING
    else:
        new_status['dynamicdns_server'] = EMPTYSTRING

    if old_status != new_status:
        disable_ssl_check = "disabled"
        use_http_basic_auth = "disabled"

        if new_status['disable_SSL_cert_check']:
            disable_ssl_check = "enabled"

        if new_status['use_http_basic_auth']:
            use_http_basic_auth = "enabled"

        _run([
            'configure', '-s', new_status['dynamicdns_server'], '-d',
            new_status['dynamicdns_domain'], '-u',
            new_status['dynamicdns_user'], '-p', '-I',
            new_status['dynamicdns_ipurl'], '-U',
            new_status['dynamicdns_update_url'], '-c', disable_ssl_check, '-b',
            use_http_basic_auth
        ], input=new_status['dynamicdns_secret'].encode())

        if old_status['enabled']:
            domain_removed.send_robust(sender='dynamicdns',
                                       domain_type='domain-type-dynamic',
                                       name=old_status['dynamicdns_domain'])
            _run(['stop'])

        if new_status['enabled']:
            domain_added.send_robust(sender='dynamicdns',
                                     domain_type='domain-type-dynamic',
                                     name=new_status['dynamicdns_domain'],
                                     services='__all__')
            _run(['start'])

        messages.success(request, _('Configuration updated'))
    else:
        logger.info('Nothing changed')


def _run(arguments, input=None):
    """Run a given command and raise exception if there was an error."""
    return actions.superuser_run('dynamicdns', arguments, input=input)