fsmgr := $(shell command -v fsmgr)

ifeq ($(fsmgr),)
$(error "no fsmgr")
endif

sudo := $(shell [ "$$(id -u)" = 0 ] || echo sudo)

.DEFAULT_GOAL = all

.PHONY: all clean cleaner
all: $(addprefix _filesystem/samizdat., seed.btrfs patch.btrfs)

_build/%: _build
_filesystem/%: _filesystem

_build _filesystem:
	$(sudo) btrfs subvolume create $@

clean:
	btrfs subvolume delete _build
cleaner: clean
	-$(sudo) btrfs subvolume delete _filesystem

_build/%.patch.btrfs: %.seed.btrfs

_build/%.seed.btrfs: %.btrfs

_filesystem/%.btrfs: _build/%.btrfs

%.btrfs:
	$(sudo) $(fsmgr) build $@