WEBRTC_DIR ?= .
WEBRTC_VERSION ?= m79
WEBRTC_OUT ?= Release
WEBRTC_GN_ARGS ?= \
	is_debug=false \
	use_sysroot=false \
	rtc_include_tests=false \
	is_clang=false \
	treat_warnings_as_errors=false \
	$(WEBRTC_GN_ARGS_EXTRA)
WEBRTC_TARGETS ?= default $(WEBRTC_TARGETS_EXTRA)
WEBRTC_LIBS ?= libwebrtc.a $(WEBRTC_LIBS_EXTRA)
WEBRTC_INCLUDES = \
	api audio base common_audio common_video logging media modules p2p pc \
	rtc_base rtc_tools video common_types.h \
	$(WEBRTC_INCLUDES_EXTRA)

SETPATH = PATH=$(WEBRTC_DIR)/depot_tools:"$$PATH"
RTC_STAMP_DEPOT = $(WEBRTC_DIR)/depot_tools/.stamp
RTC_STAMP_REPO = $(WEBRTC_DIR)/webrtc-checkout/.stamp
RTC_STAMP_VERSION = $(WEBRTC_DIR)/webrtc-checkout/.stamps/stamp-$(WEBRTC_VERSION)
RTC_STAMP_COMPILE = $(WEBRTC_DIR)/webrtc-checkout/src/out/$(WEBRTC_OUT)/.stamp
RTC_STAMP_INCLUDES = include/webrtc/.stamp

all: include/webrtc/.stamp $(patsubst %,libs/%,$(WEBRTC_LIBS))

# Get depot_tools, which contains all the tools required to work with Google software
$(RTC_STAMP_DEPOT):
	rm -rf $(WEBRTC_DIR)/depot_tools
	git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git $(WEBRTC_DIR)/depot_tools
	touch $@

# Fetch the WebRTC project itself
$(RTC_STAMP_REPO): $(RTC_STAMP_DEPOT)
	rm -rf $(WEBRTC_DIR)/webrtc-checkout && mkdir $(WEBRTC_DIR)/webrtc-checkout
	#
	# Fetch webrtc, thit will take time...
	cd $(WEBRTC_DIR)/webrtc-checkout && $(SETPATH) fetch --nohooks --no-history webrtc
	touch $@

# Check out the correct WebRTC branch/commit
$(RTC_STAMP_VERSION): $(RTC_STAMP_REPO)
	rm -rf $(WEBRTC_DIR)/webrtc-checkout/.stamps && mkdir $(WEBRTC_DIR)/webrtc-checkout/.stamps
	cd $(WEBRTC_DIR)/webrtc-checkout/src && git checkout branch-heads/$(WEBRTC_VERSION)
	#
	# Sync webrtc, this will take time...
	cd $(WEBRTC_DIR)/webrtc-checkout/src && $(SETPATH) gclient sync -D --nohooks
	touch $@

# Compile
$(RTC_STAMP_COMPILE):
	cd $(WEBRTC_DIR)/webrtc-checkout/src && $(SETPATH) gn gen out/$(WEBRTC_OUT) --args='$(WEBRTC_GN_ARGS)'
	cd $(WEBRTC_DIR)/webrtc-checkout/src && $(SETPATH) ninja -C out/$(WEBRTC_OUT) $(WEBRTC_TARGETS)
	touch $@

# Includes
$(RTC_STAMP_INCLUDES): $(RTC_STAMP_VERSION)
	rm -rf include/webrtc && mkdir -p include/webrtc
	rsync -m --recursive --include='*/' --include='*.h' --exclude='*' \
		$(patsubst %,$(WEBRTC_DIR)/webrtc-checkout/src/%,$(WEBRTC_INCLUDES)) \
		include/webrtc
	touch $@

# Libraries
libs/%.a: $(WEBRTC_DIR)/webrtc-checkout/src/out/$(WEBRTC_OUT)/obj/%.a
	@mkdir -p $(@D)
	cp $< $@

.PHONY: clean
clean:
	rm -rf $(WEBRTC_DIR)/depot_tools $(WEBRTC_DIR)/webrtc-checkout 
	rm -rf include libs

.PHONY: gn-clean
gn-clean:
	cd $(WEBRTC_DIR)/webrtc-checkout/src && $(SETPATH) gn clean out/$(WEBRTC_OUT)