#!/usr/bin/env bash

set -xeu

if [[ ${EUID} -ne 0 || ${UID} -ne 0 ]]; then
    >&2 echo "$0: error: please run this script as root"
    exit 1
fi

ROOT_DEVICE=$(mount | grep 'on / ' | awk '{print $1}')
ROOT_PARTITION="${ROOT_DEVICE: -1}"
if [[ "${ROOT_DEVICE}" =~ "mmcblk" || "${ROOT_DEVICE}" =~ "nvme" ]]; then
    PARENT_ROOT_DEVICE=$(echo "${ROOT_DEVICE}" | rev | sed -r 's/^.{2}//' | rev)
elif [[ "${ROOT_DEVICE}" =~ "vd" || "${ROOT_DEVICE}" =~ "sd" ]]; then
    PARENT_ROOT_DEVICE=$(echo "${ROOT_DEVICE}" | rev | sed -r 's/^.{1}//' | rev)
else
    >&2 echo "$0: device type unsupported"
    exit 1
fi

growpart "${PARENT_ROOT_DEVICE}" "${ROOT_PARTITION}" && GP_OK='true'
resize2fs "${ROOT_DEVICE}" && RESIZE_OK='true'

if [[ "${GP_OK}" == 'true' && "${RESIZE_OK}" == 'true' ]]; then
    systemctl disable expand-rootfs.service
    rm /etc/systemd/system/expand-rootfs.service
    systemctl daemon-reload
    rm /usr/local/bin/expand-rootfs.sh
fi