#!/usr/bin/env python3
#
# Copyright (C) 2019 VyOS maintainers and contributors
#
# 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/>.
#
# Description:
# Check if a given file exists on the system. Used for files that
# are referenced from the CLI and need to be preserved during an image upgrade.
# Warn the user if these aren't under /config

import os
import sys
import argparse

parser = argparse.ArgumentParser()
parser.add_argument("-d", "--directory", type=str, help="File must be present in this directory.")
parser.add_argument("-e", "--error", action="store_true", help="Tread warnings as errors - change exit code to '1'")
parser.add_argument("file", type=str, help="Path of file to validate")

args = parser.parse_args()

msg_prefix = "WARNING: "
if args.error:
    msg_prefix = "ERROR: "

#
# Always check if the given file exists
#
if not os.path.exists(args.file):
    print(msg_prefix + "File '{}' not found".format(args.file))
    if args.error:
        sys.exit(1)
    else:
        sys.exit(0)

#
# Optional check if the file is under a certain directory path
#
if args.directory:
    # remove directory path from path to verify
    rel_filename = args.file.replace(args.directory, '').lstrip('/')

    if not os.path.exists(args.directory + '/' + rel_filename):
        print(msg_prefix + "'{}' lies outside of '{}' directory.\n" \
              "It will not get preserved during image upgrade!".format(args.file, args.directory))
        if args.error:
            sys.exit(1)
        else:
            sys.exit(0)

sys.exit(0)