cattle-reset-elapsed() {
  (( last_cmd_at = SECONDS ))
}

cattle-ping-timer() {
  kill -USR1 "$reaper_pid"
}

cattle-slay-reaper() {
  kill -KILL "$reaper_pid"
}

cd() {
  command cd "$@"
  printf %s "$PWD" > /tmp/iterm2-prev-dir.txt
}

{
  trap "" INT
  trap cattle-reset-elapsed USR1
  last_cmd_at=0

  while sleep 1; do
    (( elapsed = SECONDS - last_cmd_at ))

    if (( elapsed > 600 )); then
      kill -KILL "$$"
      exit
    fi
  done
} &

reaper_pid=$! PROMPT_COMMAND+=(cattle-ping-timer)
trap cattle-slay-reaper EXIT

if [[ -f /tmp/iterm2-prev-dir.txt ]]; then
  cur_time=$(date +%s)
  last_mod=$(stat -f%c /tmp/iterm2-prev-dir.txt)

  if (( cur_time - last_mod > 1200 )); then
    rm -f /tmp/iterm2-prev-dir.txt
  else
    dir=$(</tmp/iterm2-prev-dir.txt)

    if [[ -d $dir ]]; then
      command cd "$dir"
    fi

    unset dir
  fi

  unset cur_time last_mod
fi