#! /bin/zsh

setopt extendedglob

function die() {
	echo "!!! $1"
	exit 1
}

### read the config file
source /etc/btv/config

### verify keyfile sanity
if [[ ! -a "${KEYFILE}" ]]; then
	echo "The keyfile (${KEYFILE}) does not exist."
	exit 2
fi

KEYFILE_OWNER=$(stat -c "%u" $KEYFILE)
KEYFILE_ACCESS=$(stat -c "%a" $KEYFILE)

if [[ ${KEYFILE_OWNER} -ne 0 ]]; then
	echo "The keyfile (${KEYFILE}) is owned by UID ${KEYFILE_OWNER}, it should be 0 (root)."
	exit 2
fi

if [[ ${KEYFILE_ACCESS} -ne 600 ]]; then
	echo "The keyfile (${KEYFILE}) has permissions ${KEYFILE_ACCESS}, it should be 600 (rw-------)."
	exit 2
fi

VERB="$1"
shift

function drop_snap {
	SNAP="${1}"
	
	for S in "${SNAP}/"*
	do
		btrfs subvolume delete "$S"
	done
	
	rmdir "${SNAP}"
}

case "$VERB" in
	(snap*)
		T="$(date +%Y-%m-%d.%H%M%S)"
		SNAP="${SNAP_DIR}/${T}"
		echo "Creating snapshot ${SNAP}"
		mkdir "${SNAP}" || die "failed to mkdir ${SNAP}"
		
		cd "${SUBVOL_DIR}" || die "failed to cd ${SUBVOL_DIR}"
		
		for SUB in ^${SUBVOL_IGNORE_PREFIX}*
		do
			btrfs subvolume snapshot -r "${SUB}" "${SNAP}/${SUB}" || die "failed to btrfs snap ${SUB}"
		done
		
		;;
	
	(list)
		cd "${SNAP_DIR}"
		
		for SNAP in *
		do
			if [[ -f "${SNAP}/streamed" ]]; then
				printf "S"
			else
				printf " "
			fi
		done
		
		echo
		echo "S = streamed to storage"
		echo "R = scheduled for removal"
		
		;;
	
	(drop)
		SNAP="${SNAP_DIR}/${1}"
		
		if [[ ! -d ${SNAP} ]]; then
			echo "Snapshot ${1} does not exist"
			exit 3
		fi
		
		echo "Dropping $SNAP"
		drop_snap "$SNAP"
		;;
	
	(clean*)
		echo ">>> gc"
		;;
	
	(stream)
		echo ">>> stream $1"
		;;
	
	(*)
		echo "Unknown verb: ${VERB}"
		exit 3
		;;
esac