golang_version := 1.12.7

golang_tarball := go$(golang_version).src.tar.gz
golang_tarball_path := src/$(golang_tarball)

golang_bin_tarball := go$(golang_version).linux-amd64.tar.gz
golang_bin_tarball_path := src/$(golang_bin_tarball)

build_dir := build/$(arch)
golang_bin_dir := $(build_dir)/go
golang_src_dir := $(build_dir)/go/src
golang_src_build_dir := $(build_dir)/target/src

prefix := $(arch)-linux-musl-

bin := $(build_dir)/target/bin/go

ifeq ($(arch), mipsel)
	prefix := mipsel-linux-musln32-
	go_arch := mipsle
else ifeq ($(arch), aarch64)
	go_arch := arm64
else ifeq ($(arch), x86_64)
	go_arch := amd64
endif

cc := $(prefix)gcc
cxx := $(prefix)g++
strip := $(prefix)strip

$(golang_bin_tarball_path):
	wget https://dl.google.com/go/$(golang_bin_tarball) -O $(golang_bin_tarball_path)

$(golang_bin_dir): $(golang_bin_tarball_path)
	mkdir -p $(build_dir)
	cd $(build_dir) && tar xvf ../../$(golang_bin_tarball_path)
	cd $(build_dir)/go && patch -p1 < ../../../set-external-linker.patch
	touch $(golang_bin_dir)

$(golang_src_build_dir): $(golang_src_dir)
	mkdir -p $(build_dir)/target
	cp -r $(golang_src_dir) $(golang_src_build_dir)

$(bin): $(golang_bin_dir) $(golang_src_build_dir)
	cd $(golang_src_build_dir) && \
		GOROOT_BOOTSTRAP=`realpath ../../go` \
		GOROOT_FINAL=/golang \
		GOOS=linux \
		GOARCH=$(go_arch) \
		CC_FOR_TARGET=$(cc) \
		CXX_FOR_TARGET=$(cxx) \
		CC=x86_64-linux-musl-gcc \
		CXX=x86_64-linux-musl-g++ \
		LD=x86_64-linux-musl-ld \
		GO_LDFLAGS="-buildmode=pie" \
		CGO_ENABLED=1 \
		./make.bash

	# if [ "$(arch)" != "x86_64" ]; then \
	# 	mv $(build_dir)/target/bin/*_*/* $(build_dir)/target/bin; \
	# 	rm -rf $(build_dir)/target/bin/*_*; \
	# 	rm -rf $(build_dir)/target/pkg/linux_amd64; \
	# 	rm -rf $(build_dir)/target/pkg/tool/linux_amd64; \
	# fi

	# rm -rf $(build_dir)/target/pkg/obj
	# rm -rf $(build_dir)/target/pkg/bootstrap

.PHONY: all clean

all: $(bin)

clean:
	rm -rf build/$(arch)