class RuboCop::Cop::Layout::DotPosition

def ampersand_dot?(node)
  node.loc.respond_to?(:dot) && node.loc.dot && node.loc.dot.is?('&.')
end

def autocorrect(corrector, dot, node)
  corrector.remove(dot)
  case style
  when :leading
    corrector.insert_before(selector_range(node), dot.source)
  when :trailing
    corrector.insert_after(node.receiver, dot.source)
  end
end

def correct_dot_position_style?(dot_line, selector_line)
  case style
  when :leading then dot_line == selector_line
  when :trailing then dot_line != selector_line
  end
end

def line_between?(first_line, second_line)
  (first_line - second_line) > 1
end

def message(dot)
  "Place the #{dot.source} on the " +
    case style
    when :leading
      'next line, together with the method name.'
    when :trailing
      'previous line, together with the method call receiver.'
    end
end

def on_send(node)
  return unless node.dot? || ampersand_dot?(node)
  return correct_style_detected if proper_dot_position?(node)
  opposite_style_detected
  dot = node.loc.dot
  message = message(dot)
  add_offense(dot, message: message) do |corrector|
    autocorrect(corrector, dot, node)
  end
end

def proper_dot_position?(node)
  receiver_line = node.receiver.source_range.end.line
  selector_line = selector_range(node).line
  # receiver and selector are on the same line
  return true if selector_line == receiver_line
  dot_line = node.loc.dot.line
  # don't register an offense if there is a line comment between the
  # dot and the selector otherwise, we might break the code while
  # "correcting" it (even if there is just an extra blank line, treat
  # it the same)
  return true if line_between?(selector_line, dot_line)
  correct_dot_position_style?(dot_line, selector_line)
end

def selector_range(node)
  # l.(1) has no selector, so we use the opening parenthesis instead
  node.loc.selector || node.loc.begin
end