#!/bin/bash
# Copyright (C) 2019 Ian Kelling
# SPDX-License-Identifier: AGPL-3.0-or-later
# SPDX-License-Identifier: GPL-3.0-or-later
# SPDX-License-Identifier: Apache-2.0

if ! test "$BASH_VERSION"; then echo "error: shell is not bash" >&2; exit 1; fi
shopt -s inherit_errexit 2>/dev/null ||: # ignore fail in bash < 4.4
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" exit status: $?, PIPESTATUS: ${PIPESTATUS[*]}" >&2' ERR
# alternatively, using https://iankelling.org/git/?p=errhandle;a=tree
# source /path/errhandle/err
# on my machine
source /a/bin/errhandle/err

[[ $EUID == 0 ]] || exec sudo -E "${BASH_SOURCE[0]}" "$@"

usage() {
  cat <<EOF
Usage: ${0##*/} TARGET_HOST
Send btrbk for root2


-h|--help  Print help and exit.

Note: Uses util-linux getopt option parsing: spaces between args and
options, short options can be combined, options before args.
EOF
  exit $1
}

##### begin command line parsing ########

# ensure we can handle args with spaces or empty.
ret=0; getopt -T || ret=$?
[[ $ret == 4 ]] || { echo "Install util-linux for enhanced getopt" >&2; exit 1; }

temp=$(getopt -l help h "$@") || usage 1
eval set -- "$temp"
while true; do
  case $1 in
    -h|--help) usage ;;
    --) shift; break ;;
    *) echo "$0: unexpected args: $*" >&2 ; usage 1 ;;
  esac
  shift
done

read -r target <<<"$@"

if [[ ! $target ]]; then
  echo $0: error: specify target
  exit 1
fi

cat >/etc/btrbk/root2.conf <<EOF

ssh_identity /root/.ssh/home
# Just a guess that local7 is a good facility to pick.
# It's a bit odd that the transaction log has to be logged to
# a file or syslog, while other output is sent to std out.
# The man does not mention a way for them to be together, but
# I dunno if setting a log level like warn might also output
# transaction info.
transaction_syslog local7

# trying this out
stream_compress zstd

archive_preserve_min latest

# so we only run one at a time
lockfile   /var/lock/btrbkroot2.lock

# default format of short does not accomidate hourly preservation setting
timestamp_format long-iso

# dont make new snapshot, we only receive new snapshots
snapshot_create no

# if something fails and it's not obvious, try doing
# btrbk -l debug -v dryrun

rate_limit no
volume /mnt/r7/amy
subvolume root_ubuntubionic
target send-receive ssh://$target/mnt/root2/btrbk
volume /mnt/r7/amy
subvolume boot_ubuntubionic
target send-receive ssh://$target/mnt/boot2/btrbk

EOF

tmpconf=$(mktemp -d)/b.conf

timeout -s 9 6 ssh root@$target mkdir -p /mnt/{b,r}oot2/btrbk

exclude=root
for base in boot root; do
  cat - /etc/btrbk/root2.conf >$tmpconf <<<"archive_exclude ${exclude}_ubuntubionic"
  btrbk -c $tmpconf archive /mnt/r7/amy/btrbk ssh://$target/mnt/${base}2/btrbk
  # swaps the vars
  exclude=$base
done