class RuboCop::Cop::Style::SymbolProc

def autocorrect(node)
  @corrections << lambda do |corrector|
    _block_method, _block_args, block_body = *node
    _receiver, method_name, _args = *block_body
    block_range =
      Parser::Source::Range.new(node.loc.expression.source_buffer,
                                node.loc.begin.begin_pos,
                                node.loc.end.end_pos)
    corrector.replace(range_with_surrounding_space(block_range, :left),
                      "(&:#{method_name})")
  end
end

def can_shorten?(block_args, block_body)
  # something { |x, y| ... }
  return false unless block_args.children.size == 1
  return false unless block_body && block_body.type == :send
  receiver, _method_name, args = *block_body
  # method in block must be invoked on a lvar without args
  return false if args
  return false unless receiver && receiver.type == :lvar
  block_arg_name, = *block_args.children.first
  receiver_name, = *receiver
  block_arg_name == receiver_name
end

def ignored_method?(name)
  ignored_methods.include?(name.to_s)
end

def ignored_methods
  cop_config['IgnoredMethods']
end

def on_block(node)
  block_send, block_args, block_body = *node
  _breceiver, bmethod_name, bargs = *block_send
  # TODO: Rails-specific handling that we should probably make
  # configurable - https://github.com/bbatsov/rubocop/issues/1485
  # we should ignore lambdas & procs
  return if block_send == PROC_NODE
  return if [:lambda, :proc].include?(bmethod_name)
  return if ignored_method?(bmethod_name)
  # File.open(file) { |f| f.readlines }
  return if bargs
  return unless can_shorten?(block_args, block_body)
  _receiver, method_name, _args = *block_body
  add_offense(node,
              :expression,
              format(MSG,
                     method_name,
                     bmethod_name))
end