#
# LVM snapshots
#
check_lvm () {
	local path=$1
	lvs $path > /dev/null 2>&1
	return $?
}

get_lvm_snapshot () {
	local path=$1
	local devname=${path##*/}
	local size=$2
	[ -z "$size" ] && size=10	

	lvcreate -s -L ${size}G -n "${devname}-snapshot" $path > /dev/null
	if [ $? -ne 0 -a $? -ne 5 ]; then 
		echo "ERROR: Failed to create LVM snapshot for: $path"
		return 1
	fi
	echo "${path%/*}/${devname}-snapshot"
	return 0
}

remove_lvm_snapshot () {
	local path=$1
	sync
	lvremove -f $path >/dev/null
}

#
# daily/weekly names rotation
#

get_backup_file () {
	local day_of_week=$( date +"%w" )  # 0-6
	local day_of_month=$( date +"%_d" ) # 1-...
	local week_of_month=$(( ($day_of_month-1)/7 ))
	[ $week_of_month -eq 4 ] && week_of_month=3
	if [ $day_of_week -eq 0 ]; then 
		echo "weekly/w${week_of_month}-"
	else
		echo "daily/d${day_of_week}-"
	fi
}

#
# RSync
#

do_rsync () {
	local localdir=$1
	local remotedir=$2

	local verbosity="--quiet --no-motd"
	[ -n "${RSYNC_EXCLUDE}" ] && excludefile="--exclude-from=${RSYNC_EXCLUDE}"
	[ -n "${RSYNC_VERBOSE}" ] && verbosity="--human-readable --progress"

	rsync --archive --links --recursive \
        	--hard-links --perms --owner --group \
		--devices --specials --times --sparse \
	        --compress --compress-level=9 ${excludefile} \
        	--rsh=ssh --delete --numeric-ids ${verbosity} \
	        "${localdir}" "${remotedir}"
}

#
# dd_gzip
#

ddssh_makedirs () {
	local sessh=$1
	local ddofbase=$2

	ssh $sessh " mkdir -p ${ddofbase}/{daily,weekly}"
}

do_ddgzipssh () {
	local ddif=$1
	local sessh=$2
	local ddofbase=$3
	
	local imgfile=${ddif##*/}
	imgfile=${imgfile%-snapshot}
	imgfile="$( get_backup_file )${imgfile}.img.gz"

	GZIP_CMD=${GZIP_CMD:-gzip}

	dd if=$ddif | $GZIP_CMD | ssh $sessh " cat > \"${ddofbase}/${imgfile}\""
}