#!/usr/bin/env bash

set -euo pipefail

function print {
    echo >&2 "riju-init-volume: $@"
}

mount_point=/mnt/riju

mkdir -p "${mount_point}"

disks="$(lsblk -l -d -b -o name,size | grep -Ev 'loop|NAME')"
num_disks="$(wc -l <<< "${disks}")"

if [[ "${num_disks}" != 2 ]]; then
    print "found unexpected number of disks from lsblk:"
    printf >&2 '%s\n' "${disks}"
    exit 1
fi

disk="$(sort -n -k2 <<< "${disks}" | tail -n1 | awk '{ print $1 }')"
print "identified data volume: ${disk}"

num_parts="$(lsblk -l -o name | (grep "${disk}." || true) | wc -l)"
print "volume has ${num_parts} partition(s)"
if [[ "${num_parts}" != 1 ]]; then
    print "repartitioning so we have exactly one partition"
    sfdisk -X gpt "/dev/${disk}" <<< ";"
    print "waiting for 1 second so that partitions show up in /dev"
    sleep 1
fi

part="$(lsblk -l -o name | (grep "${disk}." || true) | head -n1)"
print "identified data partition: ${part}"

if ! blkid "/dev/${part}" | grep -q "\bUUID="; then
    print "no filesystem detected; initializing with ext4"
    mkfs.ext4 "/dev/${part}"
fi

blkid_env="$(blkid /dev/${part} -o export)"
uuid="$(eval "${blkid_env}"; echo "${UUID}")"

print "identified filesystem UUID: ${uuid}"

if ! cat /etc/fstab | grep -q "${uuid}"; then
    print "filesystem not listed in /etc/fstab; appending"
    cat <<EOF >> /etc/fstab
UUID=${uuid} ${mount_point} ext4 defaults 0 2
EOF
fi

mount -a

print "filesystem mounted at ${mount_point}"

docker_args="-g ${mount_point}/docker"

if ! cat /lib/systemd/system/docker.service | grep -q -- "${docker_args}"; then
    print "adding '${docker_args}' to docker.service"
    sed -Ei "s|ExecStart=.+|& ${docker_args}|" /lib/systemd/system/docker.service

    print "restarting Docker daemon"
    systemctl daemon-reload
    systemctl restart docker
fi