module RuboCop::Cop::FrozenStringLiteral

def frozen_string_literal?(node)
  frozen_string = if target_ruby_version >= 3.0
                    uninterpolated_string?(node) || uninterpolated_heredoc?(node)
                  else
                    FROZEN_STRING_LITERAL_TYPES_RUBY27.include?(node.type)
                  end
  frozen_string && frozen_string_literals_enabled?
end

def frozen_string_literal_comment_exists?
  leading_comment_lines.any? { |line| MagicComment.parse(line).valid_literal_value? }
end

def frozen_string_literal_specified?
  leading_comment_lines.any? do |line|
    MagicComment.parse(line).frozen_string_literal_specified?
  end
end

def frozen_string_literals_disabled?
  leading_comment_lines.any? do |line|
    MagicComment.parse(line).frozen_string_literal == false
  end
end

def frozen_string_literals_enabled?
  ruby_version = processed_source.ruby_version
  return false unless ruby_version
  # Check if a magic string literal comment specifies what to do
  magic_comments = leading_comment_lines.filter_map { |line| MagicComment.parse(line) }
  if (literal_magic_comment = magic_comments.find(&:frozen_string_literal_specified?))
    return literal_magic_comment.frozen_string_literal?
  end
  # TODO: Ruby officially abandon making frozen string literals default
  # for Ruby 3.0.
  # https://bugs.ruby-lang.org/issues/11473#note-53
  # Whether frozen string literals will be the default after Ruby 4.0
  # or not is still unclear as of July 2024.
  # It may be necessary to add this code in the future.
  #
  #   return ruby_version >= 4.0 if string_literals_frozen_by_default?.nil?
  #
  # And the above `ruby_version >= 4.0` is undecided whether it will be
  # Ruby 4.0 or others.
  # See https://bugs.ruby-lang.org/issues/20205 for details.
  # For now, offer a configuration value to override behavior is using RUBYOPT.
  return false if string_literals_frozen_by_default?.nil?
  string_literals_frozen_by_default?
end

def leading_comment_lines
  first_non_comment_token = processed_source.tokens.find { |token| !token.comment? }
  if first_non_comment_token
    # `line` is 1-indexed so we need to subtract 1 to get the array index
    processed_source.lines[0...first_non_comment_token.line - 1]
  else
    processed_source.lines
  end
end

def leading_magic_comments
  leading_comment_lines.map { |line| MagicComment.parse(line) }
end

def uninterpolated_heredoc?(node)
  return false unless node.dstr_type? && node.heredoc?
  node.children.all?(&:str_type?)
end

def uninterpolated_string?(node)
  node.str_type? || (
    node.dstr_type? && node.each_descendant(:begin, :ivar, :cvar, :gvar).none?
  )
end