#!/usr/bin/python3
#
# 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/>.
#
"""
Configuration helper for Cockpit.
"""

import argparse

import augeas
from plinth import action_utils

CONFIG_FILE = '/etc/cockpit/cockpit.conf'


def parse_arguments():
    """Return parsed command line arguments as dictionary."""
    parser = argparse.ArgumentParser()
    subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')

    subparser = subparsers.add_parser('setup',
                                      help='Setup Cockpit configuration')
    subparser.add_argument('domain_names', nargs='*',
                           help='Domain names to be allowed')
    subparsers.add_parser('enable', help='Enable Cockpit')
    subparsers.add_parser('disable', help='Disable Cockpit')
    subparser = subparsers.add_parser(
        'add-domain',
        help='Allow a new domain to be origin for Cockpit\'s WebSocket')
    subparser.add_argument('domain_name', help='Domain name to be allowed')
    subparser = subparsers.add_parser(
        'remove-domain',
        help='Disallow a new domain from being origin for Cockpit\'s '
        'WebSocket')
    subparser.add_argument('domain_name', help='Domain name to be removed')

    subparsers.required = True
    return parser.parse_args()


def subcommand_setup(arguments):
    """Setup Cockpit configuration."""
    aug = load_augeas()
    origins = [
        _get_origin_from_domain(domain) for domain in arguments.domain_names
    ]
    origins += ['https://localhost', 'https://localhost:4430']
    _set_origin_domains(aug, origins)
    aug.set('/files' + CONFIG_FILE + '/WebService/UrlRoot', '/_cockpit/')
    aug.save()

    with action_utils.WebserverChange() as webserver_change:
        webserver_change.enable('cockpit-freedombox')

    action_utils.service_restart('cockpit.socket')


def subcommand_enable(_):
    """Enable web configuration and reload."""
    action_utils.service_enable('cockpit.socket')
    action_utils.webserver_enable('cockpit-freedombox')


def subcommand_disable(_):
    """Disable web configuration and reload."""
    action_utils.webserver_disable('cockpit-freedombox')
    action_utils.service_disable('cockpit.socket')


def _get_origin_domains(aug):
    """Return the list of allowed origin domains."""
    origins = aug.get('/files' + CONFIG_FILE + '/WebService/Origins')
    return set(origins.split()) if origins else set()


def _set_origin_domains(aug, origins):
    """Set the list of allowed origin domains."""
    aug.set('/files' + CONFIG_FILE + '/WebService/Origins', ' '.join(origins))


def _get_origin_from_domain(domain):
    """Return the origin that should be allowed for a domain."""
    return 'https://{domain}'.format(domain=domain)


def subcommand_add_domain(arguments):
    """Allow a new domain to be origin for Cockpit's WebSocket."""
    aug = load_augeas()
    origins = _get_origin_domains(aug)
    origins.add(_get_origin_from_domain(arguments.domain_name))
    _set_origin_domains(aug, origins)
    aug.save()


def subcommand_remove_domain(arguments):
    """Disallow a domain from being origin for Cockpit's WebSocket."""
    aug = load_augeas()
    origins = _get_origin_domains(aug)
    origins.remove(_get_origin_from_domain(arguments.domain_name))
    _set_origin_domains(aug, origins)
    aug.save()


def load_augeas():
    """Initialize Augeas."""
    aug = augeas.Augeas(
        flags=augeas.Augeas.NO_LOAD + augeas.Augeas.NO_MODL_AUTOLOAD)
    aug.set('/augeas/load/inifile/lens', 'Puppet.lns')
    aug.set('/augeas/load/inifile/incl[last() + 1]', CONFIG_FILE)
    aug.load()
    return aug


def main():
    """Parse arguments and perform all duties."""
    arguments = parse_arguments()

    subcommand = arguments.subcommand.replace('-', '_')
    subcommand_method = globals()['subcommand_' + subcommand]
    subcommand_method(arguments)


if __name__ == '__main__':
    main()