class RuboCop::Cop::Rails::Delegate

end
foo.bar
def bar
private
# good
delegate :bar, to: :foo, prefix: true
# good
end
foo.bar
def foo_bar
# bad
delegate :bar, to: :foo
# good
end
foo.bar
def bar
# bad
@example
automatically with delegate method.
This cop looks for delegations, that could have been created

def arguments_match?(args, body) 

def arguments_match?(args, body)
  _receiver, _method_name, *arguments = *body
  arg_array = Array(args)
  argument_array = Array(arguments)
  arg_array.size == argument_array.size && (
    arg_array == argument_array ||
    arg_array.map(&:children) == argument_array.map(&:children)
  )
end

def autocorrect(node) 

def autocorrect(node)
  method_name, _args, body = *node
  delegation = ["delegate :#{body.children[1]}",
                "to: :#{body.children[0].children[1]}"]
  if method_name == prefixed_method_name(body)
    delegation << ['prefix: true']
  end
  lambda do |corrector|
    corrector.replace(node.loc.expression, delegation.join(', '))
  end
end

def delegate?(body) 

def delegate?(body)
  receiver, * = *body
  return false unless receiver.is_a? Parser::AST::Node
  return false unless receiver.type == :send
  receiver.child_nodes.empty?
end

def method_name_matches?(method_name, body) 

def method_name_matches?(method_name, body)
  _receiver, property_name, *_args = *body
  method_name == property_name ||
    method_name == prefixed_method_name(body)
end

def on_def(node) 

def on_def(node)
  method_name, args, body = *node
  return unless trivial_delegate?(method_name, args, body)
  return if private_or_protected_delegation(node)
  add_offense(node, :keyword, MSG)
end

def prefixed_method_name(body) 

def prefixed_method_name(body)
  receiver, property_name, *_args = *body
  _receiver, target, *_args = *receiver
  [target, property_name].join('_').to_sym
end

def private_or_protected_before(line) 

def private_or_protected_before(line)
  (processed_source[0..line].map(&:strip) & %w(private protected)).any?
end

def private_or_protected_delegation(node) 

def private_or_protected_delegation(node)
  line = node.loc.line
  private_or_protected_before(line) ||
    private_or_protected_inline(line)
end

def private_or_protected_inline(line) 

def private_or_protected_inline(line)
  processed_source[line - 1].strip =~ /\A(private )|(protected )/
end

def trivial_delegate?(method_name, args, body) 

def trivial_delegate?(method_name, args, body)
  body && delegate?(body) &&
    method_name_matches?(method_name, body) &&
    arguments_match?(args, body)
end