#!/bin/sh

set -eu

default_dir=${1:-$HOME}

new_session() {
  printf 'New session name: '
  IFS= read -r session_name

  [ -n "$session_name" ] || return 0

  if ! tmux has-session -t "$session_name" 2>/dev/null; then
    tmux new-session -d -s "$session_name" -c "$default_dir"
  fi

  tmux switch-client -t "$session_name"
  exit 0
}

while :; do
  selection=$(
    tmux list-sessions -F '#{session_name}' |
      fzf \
        --layout=reverse \
        --height=100% \
        --border \
        --prompt='sessions> ' \
        --header='Enter switch  Ctrl-n new  Ctrl-k kill' \
        --preview 'tmux list-windows -t {} -F "#{window_index}: #{window_name}#{?window_active, [active],}"' \
        --preview-window='right,60%' \
        --expect=ctrl-k,ctrl-n
  ) || exit 0

  key=$(printf '%s\n' "$selection" | sed -n '1p')
  session_name=$(printf '%s\n' "$selection" | sed -n '2p')

  case "$key" in
    ctrl-n)
      new_session
      ;;
  esac

  [ -n "$session_name" ] || exit 0

  case "$key" in
    ctrl-k)
      tmux kill-session -t "$session_name"
      ;;
    *)
      tmux switch-client -t "$session_name"
      exit 0
      ;;
  esac
done