#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2020 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Transforms power_manager prefs/defaults into enforceable schema."""

import argparse
import os
import re
import sys

THIS_DIR = os.path.dirname(__file__)

PREF_DEF_FILE = os.path.join(
    THIS_DIR, '../../power_manager/common/power_constants.cc')
PREF_DEFAULTS_DIR = os.path.join(THIS_DIR, '../../power_manager/default_prefs')


def ParseArgs(argv):
  """Parse the available arguments.

  Invalid arguments or -h cause this function to print a message and exit.

  Args:
    argv: List of string arguments (excluding program name / argv[0])

  Returns:
    argparse.Namespace object containing the attributes.
  """
  parser = argparse.ArgumentParser(
      description='Generates power_manager prefs jsonschema')
  parser.add_argument(
      '-o',
      '--output',
      type=str,
      help='Output file that will be generated by the transform')
  return parser.parse_args(argv)


def Main(output):
  """Transforms power_manager prefs/defaults into jsonschema.

  Args:
    output: Output file that will be generated by the transform.
  """
  result_lines = ["""powerd_prefs_default: &powerd_prefs_default
  description: For details, see https://chromium.googlesource.com/chromiumos/platform2/+/HEAD/power_manager/
  type: string

powerd_prefs: &powerd_prefs"""]

  with open(PREF_DEF_FILE, 'r') as defs_stream:
    defs_content = defs_stream.read()
    prefs = re.findall(
        r'const char .*Pref.. =[ |\n] *"(.*)";', defs_content, re.MULTILINE)
    for pref in prefs:
      default_pref_path = os.path.join(PREF_DEFAULTS_DIR, pref)
      pref_name = pref.replace('_', '-')
      if os.path.exists(default_pref_path):
        result_lines.append('  %s:' % pref_name)
        result_lines.append('    <<: *powerd_prefs_default')
        with open(default_pref_path, 'r') as default_stream:
          default = default_stream.read()
          result_lines.append(
              '    default: "%s"' % default.strip().replace('\n', ' '))
      else:
        result_lines.append('  %s: *powerd_prefs_default' % pref_name)


  full_result = '\n'.join(result_lines)
  if output:
    with open(output, 'w') as output_stream:
      print(full_result, file=output_stream)
  else:
    print(full_result)


def main(argv=None):
  """Main program which parses args and runs

  Args:
    argv: List of command line arguments, if None uses sys.argv.
  """
  if argv is None:
    argv = sys.argv[1:]
  opts = ParseArgs(argv)
  Main(opts.output)


if __name__ == '__main__':
  sys.exit(main(sys.argv[1:]))