_printcap='/etc/lprng/printcap'
_service='lpd.service'

_clean_untracked() {
  set -u
  local _untracked=(
    '/usr/share/doc/lprng/lpd.conf.sample'
    '/usr/share/doc/lprng/lpd.perms.sample'
    '/usr/share/doc/lprng/printcap.sample'
  )
  # These untracked files can't be cleaned any other way
  rm -f "${_untracked[@]}"
  set +u
}

_post_ui() {
  set -u
  systemctl daemon-reload
  if systemctl -q is-active 'org.cups.cups-lpd.socket'; then
    echo 'You may need to disable cups-lpd with'
    echo "  systemctl disable --now 'org.cups.cups-lpd.socket'"
  fi
  if ! systemctl -q is-enabled "${_service}"; then
    echo 'Enable your lpd server with'
    echo "  sudo systemctl enable --now '${_service}'"
  fi
  if ! grep -qe '^[a-zA-Z]' "${_printcap}"; then
    echo "Add some printers to ${_printcap}"
  fi
  set +u
}

post_upgrade() {
  _post_ui
  _clean_untracked
}

post_install() {
  _post_ui
  _clean_untracked
}

pre_remove() {
  set -u
  systemctl stop "${_service}"
  systemctl disable "${_service}"
  set +u
  _clean_untracked
}