#!/bin/sh
# ==============================================================================
# HassOS partition expander
# ==============================================================================
set -e

DEVICE_CHILD="$(findfs LABEL="hassos-data")"
DEVICE_CHILD_NAME="$(basename "${DEVICE_CHILD}")"
DEVICE_ROOT_NAME="$(lsblk -no pkname "${DEVICE_CHILD}")"
DEVICE_ROOT="/dev/${DEVICE_ROOT_NAME}"
PART_NUM="$(cat "/sys/class/block/${DEVICE_CHILD_NAME}/partition")"

# Get partition label type
PART_TABLE="$(sfdisk -lqJ "${DEVICE_ROOT}")"
PART_LABEL="$(echo "${PART_TABLE}" | jq -r '.partitiontable.label')"

if [ "${PART_LABEL}" = "gpt" ]; then
    echo "[INFO] Detected GPT partition label"
    # We cannot use .partitiontable.lastlba from the json output as we might
    # still have the backup GPT not at the end of the disk. Calculate last
    # usable LBA using disk size
    LAST_USABLE_LBA=$(( $(cat "/sys/class/block/${DEVICE_ROOT_NAME}/size") - 34 ))
else
    echo "[INFO] Detected MBR partition label"
    LAST_USABLE_LBA=$(cat "/sys/class/block/${DEVICE_ROOT_NAME}/size")
fi

# Calculate end of data partition
JQ_FILTER=".partitiontable.partitions[] | select ( .node == \"${DEVICE_CHILD}\" ) | .start + .size"
DATA_PARTITION_END="$(echo "${PART_TABLE}" | jq "${JQ_FILTER}")"

# Need resize? Ignore everything less than 8MB since that could be partition
# alignment rounding...
UNUSED_BLOCKS=$(( LAST_USABLE_LBA - DATA_PARTITION_END ))
if [ "${UNUSED_BLOCKS}" -le "16384" ]; then
    echo "[INFO] No resize of data partition needed"
    exit 0
fi

echo "[INFO] Update hassos-data partition ${PART_NUM}"
if [ "${PART_LABEL}" = "gpt" ]; then
    sgdisk -e "${DEVICE_ROOT}"
    sgdisk -d "${PART_NUM}" \
        -n "${PART_NUM}:0:0" \
        -c "${PART_NUM}:hassos-data" \
        -t "${PART_NUM}:0FC63DAF-8483-4772-8E79-3D69D8477DE4" \
        -u "${PART_NUM}:a52a4597-fa3a-4851-aefd-2fbe9f849079" \
        "${DEVICE_ROOT}"
    sgdisk -v "${DEVICE_ROOT}"
else
    echo ", +" | sfdisk -N "${PART_NUM}" "${DEVICE_ROOT}" --force
    sfdisk -V "${DEVICE_ROOT}"
fi

partx -u "${DEVICE_ROOT}"

# Resize filesystem
echo "[INFO] Resize hassos-data filesystem"
e2fsck -y "${DEVICE_CHILD}"
resize2fs -f "${DEVICE_CHILD}"

echo "[INFO] Finish hassos-data resizing"