#!/usr/bin/env python3

# Copyright 2022 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 = len(config) - len(verify_config)
    if 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()