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

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

-include ../Makefile.config

.PHONY: $(filelink)


$(file):
	@$(MAKE) -f $(makefilename) $(filelink)
	@test -e $(filelink) && mkdir -p $(dir $@)
	@test -e $(filelink) && ln -fs $(cachepath)/$$(readlink $(filelink)) $@

$(filelink): $(newfile)
	@if [ "$$(readlink $@)" != "$(^F)" ]; then \
		rm -rf $(cachepath)/t1 $(cachepath)/t2; \
		mkdir $(cachepath)/t1 $(cachepath)/t2; \
		if [ -e $@ -a -e $^ ]; then \
			if tar -xf $@ -C $(cachepath)/t1 2>/dev/null; then \
				tar -xf $^ -C $(cachepath)/t2 2>/dev/null; \
				diff -r $(cachepath)/t1 $(cachepath)/t2 >/dev/null && rm $^; \
				chmod -R +x $(cachepath)/t1 $(cachepath)/t2; \
				rm -rf $(cachepath)/t1 $(cachepath)/t2; \
			else \
				diff -q $^ $@ >/dev/null && rm $^; \
			fi; \
		fi; \
		test -e $@ -a -e $^ && rm -f $(cachepath)/$$(readlink $@); \
		test -e $^ && ln -fs $(notdir $^) $@; \
	fi || true

$(newfile):
	@if [ -z "$(NO_UPDATES)" -o ! -e $(filelink) ]; then \
		mkdir -p $(@D); \
		if [ -n "$(url)" ]; then \
			wget -T 30 -t 2 "$(url)" -O $@ || rm -f $@ || true; \
		elif [ -n "$(rule)" ]; then \
			$(MAKE) -sf Makefile $(rule) file=$@ version=$(version) >&2 || rm -f $@ || true; \
		fi; \
	else \
		echo "No update check" >&2; \
	fi


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


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

clean_all:
	rm -rf $(cachepath)/*