#!/bin/sh

if [ -z "$1" ] || [ "$1" = "--help" ]; then
	cat >&2 << EOH
Usage

	$0 [backup-dir] restore-mount-point

This is script to restore from rsnapshot-based backup.
It copies directory tree from backup dir to restore-mount-point
and updaes fstab there to have correct UUIDs of partitions mounted
underneath this mountpoint. 

You have to manually create partitions and filesystems on them and mount
it under target mount point.
EOH
fi

if [ -z "$2" ]; then
	# only one parameter is specified it is assumed to be target. So in
	# the current directory must be only one backup 
	for candidate in alpha.0/etc "$(echo ./*/alpha.0/etc)"; do
		if [ -d "$candidate" ]; then
			backup="$(dirname "$candidate")"
			break
		fi
	done
	if [ -z "$backup" ]; then
		echo "Cannot find backup directory. Please specify it explicitely" >&2
		exit 1
	fi
	restore="$1"
else
	backup="$1"
	restore="$2"
fi


if [ ! -d "$backup/etc" ]||[ ! -d "$backup/home" ]||[ ! -d "$backup/usr" ]; then
	echo "$backup doesn't look like full backup of unix filesystem"
fi

if [ ! -d "$restore" ]; then
	echo "Restore mount point $restore doesn't exists" >&2
	exit 1
fi
tempf=$(mktemp)
mount|while read -r dev _ point _ type rest; do
	case $point in
	$restore|$restore/*)
		uuid="$(blkid "$dev" --output export|grep '^UUID')"
		targetpoint=${point#$restore}
		[ -z "$targetpoint" ]&&targetpoint=/
		fsline=$(printf "%s %12s %s   defaults  0    0" "$uuid" "$targetpoint" "$type")
		echo "$fsline">>"$tempf"
	;;
	*) 
	:
	;;
	esac
done
# Scan for swap partitions on the same drive
root="$(df "$restore" --output=source|tail -1)"
drive="${root%[0-9]}"
for part in "$drive"*; do
	data="$(blkid "$part" --output=export)"
	uuid=$(echo "$data"|grep "^UUID=")
	if echo "$data"|grep -q TYPE=swap; then
		echo "$uuid none         swap	  sw    1  0" >> "$tempf"
	fi
done
while [ ! -e "$drive" ]; do
	drive=${drive%?}
done
echo "Going to install boot loader on $drive"
#read fstab and copy out all lines which do not start with UUID
while read -r line; do
	case "$line" in
	UUID=*) 
		if  [ -e "$tempf" ]; then
		cat "$tempf"
		rm "$tempf"
		fi
		;;
	*)
		echo "$line"
		;;
	esac
done < "$backup/etc/fstab" > /tmp/fstab.new
#  restoring backup
echo "Restoring data"
rsync -a "$backup/" "$restore/" || exit 1
echo "Updatinf fstab"
cp /tmp/fstab.new "$restore/etc/fstab"
rm "$restore/etc/udev/rules.d"/*-persistent-net.rules
echo "Installing bootloader"
mount -t proc none "$restore/proc"
mount -o bind /dev "$restore/dev"
mount -t sysfs sys "$restore/sys"
chroot "$restore" update-grub
chroot "$restore" grub-install "$drive"
umount "$restore/sys"
umount "$restore/dev"
umount "$restore/proc"

echo "Restore completed. Please reboot"