# frozen_string_literal: true

FILE_EXTENSION = ".rb"
FROZEN_STRING_MAGIC_COMMENT = "# frozen_string_literal: true"
SHEBANG_COMMENT = "#!"

def get_files_with_no_magic_comment(files)
  files.select do |path|
    path.end_with?(FILE_EXTENSION) &&
      !file_has_frozen_string_magic_comment?(path)
  end
end

def file_has_frozen_string_magic_comment?(path)
  File.open(path) do |file|
    first_line = file.gets

    line_has_frozen_string_magic_comment?(first_line) ||
      (line_has_shebang?(first_line) &&
        line_has_frozen_string_magic_comment?(file.gets))
  end
end

def line_has_frozen_string_magic_comment?(line)
  line&.start_with?(FROZEN_STRING_MAGIC_COMMENT)
end

def line_has_shebang?(line)
  line&.start_with?(SHEBANG_COMMENT)
end

files_to_fix = get_files_with_no_magic_comment(git.added_files)

if files_to_fix.any?
  warn 'This merge request adds files that do not enforce frozen string literal. ' \
    'See https://gitlab.com/gitlab-org/gitlab-foss/issues/47424 for more information.'

  if GitlabDanger.new(helper.gitlab_helper).ci?
    markdown(<<~MARKDOWN)
      ## Enable Frozen String Literal

      The following files should have `#{FROZEN_STRING_MAGIC_COMMENT}` on the first line:

      * #{files_to_fix.map { |path| "`#{path}`" }.join("\n* ")}
    MARKDOWN
  end
end