#!/usr/bin/env python3
#
# Copyright VyOS maintainers and contributors <maintainers@vyos.io>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import re
import sys

allowedChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '.', '+', '*', '?', '^', '$', '(', ')', '[', ']', '{', '}', '|', '\\', ':', '-', '_', ' ' }

if __name__ == '__main__':
    if len(sys.argv) != 2:
        sys.exit(1)

    value = sys.argv[1]

    # Require at least one well-formed large-community tuple in the pattern. 
    tmp = value.split(':')
    if len(tmp) < 3:
        sys.exit(1)

    # Simple guard against invalid community & 1003.2 pattern chars
    if not set(value).issubset(allowedChars):
        sys.exit(1)

    # Don't feed FRR badly formed regex
    try:
        re.compile(value)
    except re.error:
        sys.exit(1)

    sys.exit(0)