path := ~/.mld
filebase = $(basename $(notdir $(file)))
suffix = $(subst .,,$(suffix $(file)))
version ?= $(shell date +%Y.%m.%d)
filelink = $(path)/$(notdir $(file))
newfile = $(path)/$(filebase)-$(version).$(suffix)

# file = src/name.tgz
# url = "http://surce-file.tgz"
# rule = src/create-source-file.tgz

.PHONY: $(filelink)


$(file): $(filelink)
	@test -e $^ && mkdir -p $(dir $@)
	@test -e $^ && ln -fs $(path)/$(shell readlink $^) $@

$(filelink): $(newfile)
	@if [ "$(shell readlink $@)" != "$(^F)" ]; then \
		test -e $@ -a -e $^ && diff $^ $@ >/dev/null && rm $^; \
		test -e $@ -a -e $^ && rm -f $(path)/$(shell readlink $@); \
		test -e $^ && ln -fs $(notdir $^) $@; \
	fi || true

$(newfile):
	@mkdir -p $(@D)
	@if [ -n "$(url)" ]; then \
		wget -T 5 -t 2 "$(url)" -O $@ || rm -f $@ || true; \
	elif [ -n "$(rule)" ]; then \
		$(MAKE) -sf Makefile $(rule) file=$@ version=0 >&2 || rm -f $@ || true; \
	fi


version: $(filelink)
	@readlink $^ | sed "s/.*-\(.*\)\.$(suffix)/\\1/g"


clean:
	rm -f $(path)/$(name)-* $(path)/$(name).*

clean_all:
	rm -rf $(path)/*