#!/usr/bin/env zsh 
tmux start

attach_tmux () {
  TMUX_SESSION="$1"
  tmux attach -t "$TMUX_SESSION" -d
}

new_tmux () {
  TMUX_SESSION="$1"
  exec tmux new-session -s "$TMUX_SESSION"
}

tmux_sessions() {
  echo
  tmux ls
}

complete_sessions() {
  tmux_sessions | fzf --bind alt-enter:print-query -n 1 -d: | cut -d: -f1
}

if [[ x"$1" == x ]]; then
  TMUX_SESSION="$(complete_sessions)"

  if [[ -n "$TMUX_SESSION" ]]; then
    attach_tmux "$TMUX_SESSION" && exit 0
  fi

  echo -n "No such session '$TMUX_SESSION', new session [y/N]? "
  read NEW_SESSION
  NEW_SESSION="${NEW_SESSION/Y/y}"

  if [[ x"${NEW_SESSION[1]}" == x'y' ]]; then
    new_tmux "$TMUX_SESSION"
  fi

  echo "Either you decided not to create a new session or something went _horribly_ wrong!"
  read BOB
else
  attach_tmux "$1" || new_tmux "$1"
fi