class RuboCop::Cop::Style::DotPosition

def autocorrect(node)
  receiver, _method_name, *_args = *node
  lambda do |corrector|
    corrector.remove(node.loc.dot)
    case style
    when :leading
      corrector.insert_before(selector_range(node), '.')
    when :trailing
      corrector.insert_after(receiver.source_range, '.')
    end
  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(_node)
  'Place the . 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.loc.dot
  if proper_dot_position?(node)
    correct_style_detected
  else
    add_offense(node, :dot) { opposite_style_detected }
  end
end

def proper_dot_position?(node)
  receiver, _method_name, *_args = *node
  receiver_line = 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)
  if node.loc.selector
    node.loc.selector
  else
    # l.(1) has no selector, so we use the opening parenthesis instead
    node.loc.begin
  end
end