#!/bin/bash
# Script to restore a virtual machine disk with Borg (plan B)
#
# Copyright (C) 2023 Adrien 'neox' Bourmault <neox@a-lec.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# Exit on error
set -e

# Enable quitting properly
trap clean_exit INT

function clean_exit() {
        echo "Exiting..."
	sync
	umount -q /tmp/mnt/${vm}
	umount -q /tmp/mnt/${vm}-remote

	if [ ! -z ${loopdisk} ]; then
		losetup -d ${loopdisk}
	fi
	rm -r /tmp/mnt
}


vm=$1
dest=$2
backuphost=$3

generic_image="/srv/vmverse/installation/generic.a-lec.org.raw"

if [[ $# != 3 ]]
then
    echo "ERROR: 3 parameters required : vm domain, destination path, backup host"
    exit 1
fi

# Checking saves
echo -e "Checking backups...\n"
export BORG_PASSPHRASE=$(ssh root@${backuphost} cat /srv/borg/.borg-passphrase)
DATES=$(borg list --short root@${backuphost}:/var/backups/borg/${vm}.repo)
IFS=$'\n' DATES=(${DATES})

echo "* BACKUPS AVAILABLE *"
echo "---------------------"
echo " "

i=0
while [ $i -lt ${#DATES[@]} ]
do
    echo -e "\t${i}) ${DATES[i]}"
    i=$((i+1))
done

# Asking for save to restore
read -p "Please choose a backup to restore: " backupdate
echo -e "\nOK\n"

# Preparing path
echo "Preparing path..."
mkdir -p /tmp/mnt/${vm}
mkdir -p /tmp/mnt/${vm}-remote
mkdir -p $(dirname ${dest})

# Creating new disk
echo "Creating new disk..."
cp --reflink ${generic_image} ${dest}

# Mounting
echo "Mounting devices..."
loopdisk=$(losetup -fPL ${dest} --show)
mount ${loopdisk}p1 /tmp/mnt/${vm}
borg mount root@${backuphost}:/var/backups/borg/${vm}.repo::${DATES[backupdate]} /tmp/mnt/${vm}-remote

# Syncing
echo "Syncing now !"
sleep 1
rsync -ar --progress --sparse /tmp/mnt/${vm}-remote/. /tmp/mnt/${vm}

# Cleaning up
echo -e "\nOK\n"
clean_exit