"""Windows PE/COFF resource file helper."""

import re


class WindowsResourceFileHelper:
  """Windows PE/COFF resource file helper."""

  # Message string specifiers that are considered white space.
  _MESSAGE_STRING_WHITE_SPACE_SPECIFIER_RE = re.compile(r'(%[0b]|[\r\n])')

  # Message string specifiers that expand to text.
  _MESSAGE_STRING_TEXT_SPECIFIER_RE = re.compile(r'%([ .!%nrt])')

  # Curly brackets in a message string.
  _MESSAGE_STRING_CURLY_BRACKETS = re.compile(r'([\{\}])')

  # Message string specifiers that expand to a variable place holder.
  _MESSAGE_STRING_PLACE_HOLDER_SPECIFIER_RE = re.compile(
      r'%([1-9][0-9]?)[!]?[s]?[!]?')

  @classmethod
  def _MessageStringPlaceHolderSpecifierReplacer(cls, match_object):
    """Replaces message string place holders into Python format() style.

    Args:
      match_object (re.Match): regular expression match object.

    Returns:
      str: message string with Python format() style place holders.
    """
    expanded_groups = []

    for group in match_object.groups():
      try:
        place_holder_number = int(group, 10) - 1
        expanded_group = f'{{{place_holder_number:d}:s}}'
      except ValueError:
        expanded_group = group

      expanded_groups.append(expanded_group)

    return ''.join(expanded_groups)

  @classmethod
  def FormatMessageStringInPEP3101(cls, message_string):
    """Formats a message string in Python format() (PEP 3101) style.

    Args:
      message_string (str): message string.

    Returns:
      str: message string in Python format() (PEP 3101) style.
    """
    if not message_string:
      return None

    message_string = message_string.rstrip('\0')
    message_string = cls._MESSAGE_STRING_WHITE_SPACE_SPECIFIER_RE.sub(
        r'', message_string)
    message_string = cls._MESSAGE_STRING_TEXT_SPECIFIER_RE.sub(
        r'\\\1', message_string)
    message_string = cls._MESSAGE_STRING_CURLY_BRACKETS.sub(
        r'\1\1', message_string)
    return cls._MESSAGE_STRING_PLACE_HOLDER_SPECIFIER_RE.sub(
        cls._MessageStringPlaceHolderSpecifierReplacer, message_string)
