module RuboCop::Cop::MethodComplexity

def check_complexity(node, method_name)
  # Accepts empty methods always.
  return unless node.body
  max = cop_config['Max']
  complexity = complexity(node.body)
  return unless complexity > max
  msg = format(self.class::MSG,
               method: method_name,
               complexity: complexity,
               max: max)
  add_offense(node, message: msg) do
    self.max = complexity.ceil
  end
end

def complexity(body)
  body.each_node(*self.class::COUNTED_NODES).reduce(1) do |score, n|
    score + complexity_score_for(n)
  end
end

def on_block(node)
  define_method?(node) do |name|
    check_complexity(node, name)
  end
end

def on_def(node)
  check_complexity(node, node.method_name)
end