PACKAGE = gitlab.weird-web-workers.org/golang/version

SOURCES = version.go \
	  tools.go

VERSION = 0.0.1
REVISION = $(shell git rev-parse HEAD)
BUILDTIME= "$(shell date -u +'%Y-%m-%dT%H:%M:%SZ')"

GOOS = $(shell go env GOOS)
GOARCH = $(shell go env GOARCH)

LIBRARY = $(GOPATH)/pkg/$(GOOS)_$(GOARCH)/$(PACKAGE).a

.PHONY: all clean .version.new

all: $(LIBRARY)

$(LIBRARY): $(SOURCES)
	go install $(PACKAGE)

.version.new:
	-@printf "%s\n" "$(VERSION)" "$(REVISION)" >$@

.version: .version.new
	-@diff $@ $< >/dev/null 2>&1 && rm $< || mv $< $@

version.go: version.go.m4 .version
	-@m4 -Dm4_version=$(VERSION) \
	   -Dm4_revision=$(REVISION) \
	   -Dm4_build_time=$(BUILDTIME) \
	   -Dm4_package=$(PACKAGE) \
	   $< >$@

clean:
	-@rm -f version.go 2>/dev/null
	-@rm -f .version 2>/dev/null
	-@rm -f $(LIBRARY) 2>/dev/null