Something

alias awayy {
  if (%kakaway == $null) {
    set %kakaway $ctime $1-
    msg $chan [AWAY] I am now away $+ $iif($1,: $1-) $+ , left at $time $+ .
  }
}
alias back {
  if (%kakaway != $null) {
    tokenize 32 %kakaway
    msg $chan [AWAY] I am now back $iif($2,from $2-) $+ , I left at $gettok($asctime($1),4,32) and was gone for $duration($calc($ctime - $1)) $+ .
    unset %kakaway
  }
}