#!/bin/sh
# vim: set sw=4 ts=4 sts=4 et :

cleanup() {
    if [ -n "${tmpdir}" ] && [ "${tmpdir}" != / ]; then
        if mountpoint -q "${tmpdir}"; then
            umount "${tmpdir}"
        fi
        rm -rf "${tmpdir}"
        unset tmpdir
    fi
}

copy_var() {
    dev="$1"

    echo 'Copying /var contents to data volume'
    mount -o subvol=var "${dev}" "${tmpdir}" || exit
    cp -auv /var/. "${tmpdir}" || exit
    umount "${tmpdir}"
}

format_dev() {
    dev="$1"
    printf 'Creating BTRFS filesystem on %s\n' "${dev}"
    mkfs.btrfs "${dev}" || exit

    mount "${dev}" "${tmpdir}" || exit
    btrfs subvolume create "${tmpdir}"/var || exit
    btrfs subvolume create "${tmpdir}"/var/log || exit
    umount "${dev}" || exit
}

has_fs() {
    dev="$1"
    fstype=$(blkid -o value -s TYPE "${dev}")
    [ -n "${fstype}" ]
}

datapart=$(findfs PARTLABEL=dch-data)
if [ -b "${datapart}" ]; then
    printf 'Found data partition: %s\n' "${datapart}"
else
    echo 'Could not identify data partition' >&2
    exit 1
fi

trap cleanup INT TERM QUIT EXIT
tmpdir=/run/storinit
mkdir -p "${tmpdir}"

if ! has_fs "${datapart}"; then
    format_dev "${datapart}"
fi

copy_var "${datapart}"