#!/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 glob
import os
import re
import sys


_EXCLUDE_DIRS = ('.git', '.terraform')
_EXCLUDE_RE = re.compile(r'# skip boilerplate check')
_MATCH_FILES = (
    'Dockerfile', '.py', '.sh', '.tf', '.yaml', '.yml'
)
_MATCH_STRING = (
    r'^\s*[#\*]\sCopyright [0-9]{4} Google LLC$\s+[#\*]\s+'
    r'[#\*]\sLicensed under the Apache License, Version 2.0 '
    r'\(the "License"\);\s+'
)
_MATCH_RE = re.compile(_MATCH_STRING, re.M)


def main(dir):
  "Cycle through files in dir and check for the Apache 2.0 boilerplate."
  errors, warnings = [], []
  for root, dirs, files in os.walk(dir):
    dirs[:] = [d for d in dirs if d not in _EXCLUDE_DIRS]
    for fname in files:
      if fname in _MATCH_FILES or os.path.splitext(fname)[1] in _MATCH_FILES:
        fpath = os.path.abspath(os.path.join(root, fname))
        content = open(fpath).read()
        if _EXCLUDE_RE.search(content):
          continue
        try:
          if not _MATCH_RE.search(content):
            errors.append(fpath)
        except (IOError, OSError):
          warnings.append(fpath)
  if warnings:
    print('The following files cannot be accessed:')
    print('\n'.join(' - {}'.format(s) for s in warnings))
  if errors:
    print('The following files are missing the license boilerplate:')
    print('\n'.join(' - {}'.format(s) for s in errors))
    sys.exit(1)


if __name__ == '__main__':
  if len(sys.argv) != 2:
    raise SystemExit('No directory passed.')
  main(sys.argv[1])