class RuboCop::Cop::InternalAffairs::CopDescription

def comment_body(comment_line)
  comment_line.gsub(/^\s*# /, '')
end

def comment_index(node, comment_line)
  body = comment_body(comment_line)
  node.source.index(body)
end

def first_comment_line(node)
  node.source.lines.find { |line| comment_line?(line) }
end

def on_class(node)
  return unless (module_node = node.parent) && node.parent_class
  description_beginning = first_comment_line(module_node)
  return unless description_beginning
  if description_beginning.match?(EMPTY_COMMENT_LINE_REGEX)
    register_offense_for_empty_comment_line(module_node, description_beginning)
  else
    start_with_subject = description_beginning.match(COP_DESC_OFFENSE_REGEX)
    return unless start_with_subject
    register_offense_for_wrong_word(module_node, description_beginning, start_with_subject)
  end
end

def range(node, comment_line)
  source_buffer = node.source_range.source_buffer
  begin_pos = node.source_range.begin_pos
  begin_pos += comment_index(node, comment_line)
  end_pos = begin_pos + comment_body(comment_line).length
  Parser::Source::Range.new(source_buffer, begin_pos, end_pos)
end

def register_offense_for_empty_comment_line(module_node, description_beginning)
  range = range(module_node, description_beginning)
  add_offense(range, message: MSG_STARTS_WITH_EMPTY_COMMENT_LINE) do |corrector|
    corrector.remove(range)
  end
end

def register_offense_for_wrong_word(module_node, description_beginning, start_with_subject)
  suggestion = start_with_subject['word']&.capitalize
  range = range(module_node, description_beginning)
  suggestion_for_message = suggestion_for_message(suggestion, start_with_subject)
  message = format(MSG_STARTS_WITH_WRONG_WORD, suggestion: suggestion_for_message)
  add_offense(range, message: message) do |corrector|
    if suggestion && !start_with_subject['special']
      replace_with_suggestion(corrector, range, suggestion, description_beginning)
    end
  end
end

def relevant_file?(file)
  file.match?(%r{/cop/.*\.rb\z})
end

def replace_with_suggestion(corrector, range, suggestion, description_beginning)
  replacement = description_beginning.gsub(REPLACEMENT_REGEX, "#{suggestion} ")
  corrector.replace(range, replacement)
end

def suggestion_for_message(suggestion, match_data)
  if suggestion && !match_data['special']
    "`#{suggestion}`"
  else
    'a word such as verb'
  end
end