#!/usr/bin/env python3

import glob
import os
import re
import sys


MAX_LINE_LENGTH = 100


# Files with any of these as a substring of their filename are excluded from
# consideration.
FILES_TO_EXCLUDE = [
  '/obj/',
  '/bin/',
  '/AssemblyInfo.cs',
  '/Resource.Designer.cs',
  'Shared/Levels.cs']


num_errors = 0


def emit_error(filename, line_num, error):
  global num_errors
  num_errors += 1
  print('%s:%d: %s' % (filename, line_num, error))


def lint_csharp(filename):
  with open(filename) as f:
    for i, line in enumerate(f):
      line_num = i + 1
      line = line[:-1]  # Strip trailing newline.
      if len(line) > MAX_LINE_LENGTH:
        if not re.match(r'\s*// https?:', line):
          emit_error(filename, line_num, 'line too long')
      if re.match(r'\s*//\S', line):
        emit_error(filename, line_num, 'no space between // and comment')
      match = re.match(r'\s*const.* (\w+) =', line)
      if match:
        identifier = match.group(1)
        if not re.fullmatch(r'[A-Z_]+', identifier):
          emit_error(filename, line_num,
              'const field %s should be in ALL_CAPS' % identifier)
      if re.search(r'\t', line):
        emit_error(filename, line_num, 'illegal \\t character')
      if re.search(r'\r', line):
        emit_error(filename, line_num, 'illegal \\r character')
      if re.search(r'\s+$', line):
        emit_error(filename, line_num, 'trailing whitespace')


def main(args):
  this_dir = os.path.dirname(os.path.realpath(__file__))
  sneak_root = os.path.join(this_dir, '..', '..')
  os.chdir(sneak_root)

  csharp_files = sorted(glob.glob('**/*.cs', recursive=True))
  # Remove generated files (of which there's lots).
  for exclusion_pattern in FILES_TO_EXCLUDE:
    csharp_files = [x for x in csharp_files if exclusion_pattern not in x]

  for filename in csharp_files:
    lint_csharp(filename)

  print('lint.py checked %d files and found %d errors' % (
      len(csharp_files), num_errors))

  if num_errors:
    return 1
  return 0


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