#!/bin/sh
# ==============================================================================
# Home Assistant OS data partition handling
# ==============================================================================
set -e

# Use current mount point. This avoids "Can't be the same disk!" error
# when using a drive which has been used as a data drive previously.
DATA_DEVICE_CHILD="$(findmnt --noheadings --output=source /mnt/data)"
DATA_DEVICE_ROOT="/dev/$(lsblk -no pkname "${DATA_DEVICE_CHILD}")"

if [ "${DATA_DEVICE_ROOT}" = "" ]; then
    echo "[ERROR] Data disk device not found!"
    exit 1
fi

# Move command
if [ "${1}" = "move" ] && [ -e "${2}" ]; then
    NEW_DEVICE_ROOT="${2}"

    # Check device
    if ! lsblk "${NEW_DEVICE_ROOT}" | grep disk > /dev/null 2>&1; then
        echo "[ERROR] Is not disk!"
        exit 1
    elif [ "${NEW_DEVICE_ROOT}" = "${DATA_DEVICE_ROOT}" ]; then
        echo "[ERROR] Can't be the same disk!"
        exit 1
    fi

    # Flag device
    if [ -z "${DATACTL_NOCONFIRM}" ]; then
        echo "WARNING: All partitions on ${NEW_DEVICE_ROOT} will be deleted!"
        printf "Enter \"yes\" to confirm: "
        read -r confirm
        if [ "${confirm}" != "yes" ]; then
            echo "Aborting."
            exit 1
        fi
    fi

    # Create GPT partition table with a single data partition
    cat << EOF | sfdisk --wipe-partitions=always --wipe=always "${NEW_DEVICE_ROOT}"
label: gpt
uuid=a52a4597-fa3a-4851-aefd-2fbe9f849079, type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, name=hassos-data-external
EOF

    # Since we create a new partition table etc. we are guaranteed the target
    # partition is partition 1. If the device name ends with a digit, "p" is
    # placed between device name and partition number.
    case "${NEW_DEVICE_ROOT}" in
        *[0-9]) NEW_DEVICE_PART="${NEW_DEVICE_ROOT}p1";;
        *) NEW_DEVICE_PART="${NEW_DEVICE_ROOT}1";;
    esac
    NEW_DEVICE_PART_SIZE=$(cat "/sys/class/block/$(basename "${NEW_DEVICE_PART}")/size")
    OLD_DEVICE_PART_SIZE=$(cat "/sys/class/block/$(basename "${DATA_DEVICE_CHILD}")/size")

    if [ "${NEW_DEVICE_PART_SIZE}" -lt "${OLD_DEVICE_PART_SIZE}" ]; then
        echo "[INFO] Target device too small!"
        echo "label: gpt" | sfdisk "${NEW_DEVICE_ROOT}"
        exit 1
    fi

    touch "/mnt/overlay/move-data"
    cat << EOF

Disk ${NEW_DEVICE_ROOT} has been prepared to be used as data drive and the data
move has been scheduled for the next reboot. Please reboot the device now and
make sure to leave the disk connected to the system from now on.
EOF

else
    cat << EOF
Usage: datactl move <device>

Moves data partition to external device provided by <device> (without partition
number). A new partition table and a partition for the complete device will be
created by datactl.
EOF

fi