Clojurians Log v2

anyone has a command that duplicates a line, while doing an effort to not unbalance parentheses? a naive duplication would also duplicate closing parentheses: )))) easily breaking code so I'm looking for something that given a line like this a b c))) inserts <newline><indentation>a b c. and given a line like this: let [a 42 inserts <newline><indentation>a 42 (i.e. skip let [, because that would unbalance parentheses)