Unable to get bash if condiftion to work with multiple commands per outcome

I have been trying to get various versions of this to work:

[[ -e "~/usersl" ]] && { user=`cat ~/usersl`; echo Username: $user; } || { read -p "Username:" user; echo $user > ~/usersl; }

The main goal is to have a if..then..else all in one line. From what I have read on this site and others, this should work. It should check to see if the usersl file exists and if it does then it prints out the detected username and populates the $user variable. If the usersl file doesn't exist then it should ask for the username and populate the variable at the same time then record the new username into a file. Once that has been done the next tiem the command is ran the file already exists and it just displays the username and propagates the variable. Hope my explanation isn't overly complicated but the task is very simple.

Any help is much appreciated