#!/bin/bash -e

DEVICE_NODE="/dev/mmcblk0"
DEFAULT_FS_TYPE="btrfs"

#
# check device node exist
#
if [[ ! -b "${DEVICE_NODE}" ]]; then
    echo "${DEVICE_NODE} is not available"
    exit 0
fi

#
# check if device mounted correctly
#
if ! (mount || true) | grep "${DEVICE_NODE}"> /dev/null; then
    echo "${DEVICE_NODE} is not mounted"
else
    echo "${DEVICE_NODE} is mounted"
    exit 0
fi

#
# check filesystem
#
FS_TYPE_CHECK="$(blkid "${DEVICE_NODE}" | sed 's/.*TYPE="\([^"]*\).*/\1/' || true)"

if [[ "${FS_TYPE_CHECK}" = "" ]]; then
    FS_TYPE="unknown"
else
    FS_TYPE="${FS_TYPE_CHECK}"
fi

case "${FS_TYPE}" in
    "${DEFAULT_FS_TYPE}")
        echo "Filesystem (${FS_TYPE}) found on ${DEVICE_NODE}"
        ;;

    *)
        echo "No or unexpected filesystem (${FS_TYPE}) found on ${DEVICE_NODE}"
        if ! output=$(mkfs."${DEFAULT_FS_TYPE}" --force "${DEVICE_NODE}" 2>&1); then
            echo "failed to create ${DEFAULT_FS_TYPE} on ${DEVICE_NODE}:"
            echo "${output}"
            exit 1
        fi
        ;;
esac