# Copyright 2019 VyOS maintainers and contributors <maintainers@vyos.io>
#
# 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 <http://www.gnu.org/licenses/>.

import os
import re
import sys
import vyos.defaults

def get_system_versions():
    """
    Get component versions from running system; critical failure if
    unable to read migration directory.
    """
    system_versions = {}

    try:
        version_info = os.listdir(vyos.defaults.directories['current'])
    except OSError as err:
        print("OS error: {}".format(err))
        sys.exit(1)

    for info in version_info:
        if re.match(r'[\w,-]+@\d+', info):
            pair = info.split('@')
            system_versions[pair[0]] = int(pair[1])

    return system_versions