class RuboCop::Cop::Style::Attr

def autocorrect(node)
  _receiver, _method_name, attr_name, setter = *node
  node_expr = node.source_range
  attr_expr = attr_name.source_range
  if setter && (setter.true_type? || setter.false_type?)
    remove = range_between(attr_expr.end_pos, node_expr.end_pos)
  end
  lambda do |corrector|
    corrector.replace(node.loc.selector, replacement_method(node))
    corrector.replace(remove, '') if remove
  end
end

def on_send(node)
  return unless node.command?(:attr)
  _receiver, _method_name, *args = *node
  msg = "Do not use `attr`. Use `#{replacement_method(node)}` instead."
  add_offense(node, :selector, msg) if args.any?
end

def replacement_method(node)
  _receiver, _method_name, _attr_name, setter = *node
  if setter && (setter.true_type? || setter.false_type?)
    setter.true_type? ? 'attr_accessor' : 'attr_reader'
  else
    'attr_reader'
  end
end