#!/usr/bin/env bash
set -o errexit

main() {
  export RUNNING_AS="${RUNNING_AS:-me}"
  export RUNNING_AS_ID="$(id -u "${RUNNING_AS}")"

  export XAUTHORITY="/home/${RUNNING_AS}/.Xauthority"
  export DBUS_SESSION_BUS_ADDRESS="unix:path=/run/user/${RUNNING_AS_ID}/bus"
  export DISPLAY=:0
  export HOME="/home/${RUNNING_AS}"

  local device_id
  device_id="$(__get_device_id)"

  # libinput Natural Scrolling Enabled (282)
  /usr/bin/sudo -E -u "${RUNNING_AS}" \
    /usr/sbin/xinput set-prop "${device_id}" 282 1

  # libinput Scroll Method Enabled (285)
  /usr/bin/sudo -E -u "${RUNNING_AS}" \
    /usr/sbin/xinput set-prop "${device_id}" 285 0 0 1
}

__get_device_id() {
  /usr/bin/sudo -E -u "${RUNNING_AS}" /usr/sbin/xinput list |
    awk '/Logitech USB Trackball/ { sub(/id=/, "", $6); print $6 }'
}

main "${@}"