#!/usr/bin/python3
# coding=utf-8
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2017  Marek Marczykowski-Górecki
#                                   <marmarek@invisiblethingslab.com>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, see <https://www.gnu.org/licenses/>.

import argparse
import os

import sys

import qubes.api.admin

parser = argparse.ArgumentParser(
    description='Generate default Admin API policy')
parser.add_argument('--include-base', action='store',
    default='include',
    help='Base path for included paths (default: %(default)s)')
parser.add_argument('--dest', action='store',
    default='/etc/qubes/policy.d/90-admin-default.policy',
    help='Path where write output file to (default: %(default)s)')
parser.add_argument('--header', action='store',
    default='90-admin-default.policy.header',
    help='File to prepend to the policy (default: %(default)s)')
parser.add_argument('--verbose', action='store_true', default=False,
    help='Be verbose')
parser.add_argument('--exclude', action='store', nargs='*',
    help='Exclude service')
parser.add_argument('service', nargs='*', action='store',
    help='Generate policy for those services (default: all)')

def write_default_policy(args, apiname, clasifiers, f):
    ''' Write single default policy for given API call '''
    assert 'scope' in clasifiers, \
        'Method {} lack scope classifier'.format(apiname)
    assert any(attr in clasifiers for attr in ('read', 'write', 'execute')), \
        'Method {} lack read/write/execute classifier'.format(apiname)
    assert clasifiers['scope'] in ('local', 'global'), \
        'Method {} have invalid scope: {}'.format(apiname, clasifiers['scope'])

    file_to_include = 'admin-{scope}-{rwx}'.format(
        scope=clasifiers['scope'],
        rwx=('rwx' if clasifiers.get('write', False) or
                      clasifiers.get('execute', False)
        else 'ro'))

    if args.verbose:
        print('Service {}: include {}'.format(apiname, file_to_include),
            file=sys.stderr)
    f.write('!include-service {} * {}\n'.format(
        apiname,
        os.path.join(args.include_base, file_to_include)))


def main(args=None):
    ''' Main function of default-admin-policy tool'''
    args = parser.parse_args(args)

    with open(os.path.join(args.dest), 'w') as f:
        with open(args.header) as header_f:
            f.write(header_f.read())
        for func, apiname, _ in qubes.api.admin.QubesAdminAPI.list_methods():
            if args.service and apiname not in args.service:
                continue
            if args.exclude and apiname in args.exclude:
                continue
            write_default_policy(args, apiname, func.classifiers, f)


if __name__ == '__main__':
    sys.exit(main())