Makefile.COMMON

VERSION ?= $(error VERSION not set in including Makefile)
TARGET  ?= $(error TARGET not set in including Makefile)

SRC    ?= $(shell find . -type f -name "*.go" ! -path "./.build/*")
GOOS   ?= $(shell uname | tr A-Z a-z)
GOARCH ?= $(subst x86_64,amd64,$(patsubst i%86,386,$(shell uname -m)))

ifeq ($(GOOS),darwin)
	RELEASE_SUFFIX ?= -osx$(shell sw_vers -productVersion)
endif

GO_VERSION ?= 1.5.3

ifeq ($(shell type go >/dev/null && go version | sed 's/.*go\([0-9.]*\).*/\1/'), $(GO_VERSION))
	GOROOT := $(shell go env GOROOT)
else
	GOROOT := $(CURDIR)/.build/go$(GO_VERSION)
endif

GOURL      ?= https://golang.org/dl
GOPKG      ?= go$(GO_VERSION).$(GOOS)-$(GOARCH)$(RELEASE_SUFFIX).tar.gz
GOPATH     := $(CURDIR)/.build/gopath
GOCC       ?= $(GOROOT)/bin/go
GO         ?= GOROOT=$(GOROOT) GOPATH=$(GOPATH) $(GOCC)
GOFMT      ?= $(GOROOT)/bin/gofmt

# Never honor GOBIN, should it be set at all.
unexport GOBIN

SUFFIX   ?= $(GOOS)-$(GOARCH)
BINARY   ?= $(TARGET)
ARCHIVE  ?= $(TARGET)-$(VERSION).$(SUFFIX).tar.gz

default: $(BINARY)

$(GOCC):
	@echo Go version $(GO_VERSION) required but not found in PATH.
	@echo About to download and install go$(GO_VERSION) to $(GOROOT)
	@echo Abort now if you want to manually install it system-wide instead.
	@echo
	@sleep 5
	mkdir -p $(GOROOT)
	curl -L $(GOURL)/$(GOPKG) | tar -C $(GOROOT) --strip 1 -xz

$(BINARY): $(GOCC) $(SRC) Makefile Makefile.COMMON
	$(GO) get -d
	$(GO) build $(GOFLAGS) -o $@

.PHONY: archive
archive: $(ARCHIVE)

$(ARCHIVE): $(BINARY)
	tar -czf $@ $<

.PHONY: clean
clean:
	rm -rf $(BINARY) .build