#!/usr/bin/env python3

# Copyright 2021 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import argparse
import os
import sys

def readconfig(filename):
  config = {}
  with open(filename) as f:
      line = f.readline()
      while line:
        if not line.startswith('#') and '=' in line:
          split = line.split('=')
          config[split[0]] = split[1][:-1]  # Remove newline
        line = f.readline()
  return config

def main():
  parser = argparse.ArgumentParser(description='Generate a kernel config')
  parser.add_argument('--base', help='Base kernel config.', required=True)
  parser.add_argument('--verify', help='Verify all requested arguments appear in given file.', default='')
  parser.add_argument('dirs', help='Directories to search for additional .config files', nargs='*')

  args = parser.parse_args()
  config = readconfig(args.base)
  for d in args.dirs:
    for root, _, files in os.walk(d):
      for f in sorted(files):
        if f.endswith('.config'):
          config.update(readconfig(os.path.join(root, f)))
  config = {k: v for k, v in config.items() if v != 'n'}
  if args.verify:
    verify_config = readconfig(args.verify)
    missing = config.keys() - verify_config.keys()
    if len(missing) > 0:
      print('Desired kernel configs missing in final config:')
      print(missing)
      sys.exit(1)
  else:
    for k, v in sorted(config.items()):
      print('%s=%s' % (k, v))

if __name__ == '__main__':
  main()