class RuboCop::Cop::Style::UnlessElse

def on_if(node)
  return unless node.unless? && node.else?
  add_offense(node) do |corrector|
    body_range = range_between_condition_and_else(node, node.condition)
    else_range = range_between_else_and_end(node)
    next if part_of_ignored_node?(node)
    corrector.replace(node.loc.keyword, 'if')
    corrector.replace(body_range, else_range.source)
    corrector.replace(else_range, body_range.source)
  end
  ignore_node(node)
end

def range_between_condition_and_else(node, condition)
  range_between(condition.source_range.end_pos, node.loc.else.begin_pos)
end

def range_between_else_and_end(node)
  range_between(node.loc.else.end_pos, node.loc.end.begin_pos)
end