.DEFAULT_GOAL := all

CXX := gcc -xc++ -lstdc++ -shared-libgcc

BUILD := build
DEPS := imgui
SYNC := $(addsuffix -sync, $(DEPS))

# imgui_impl_allegro5.o imgui_impl_android.o      imgui_impl_dx9.o         
# imgui_impl_dx10.o     imgui_impl_dx11.o         imgui_impl_dx12.o        
# imgui_impl_glfw.o     imgui_impl_glut.o         imgui_impl_opengl2.o     
# imgui_impl_opengl3.o  imgui_impl_sdl2.o         imgui_impl_sdl3.o        
# imgui_impl_sdlgpu3.o  imgui_impl_sdlrenderer2.o imgui_impl_sdlrenderer3.o
# imgui_impl_vulkan.o   imgui_impl_wgpu.o         imgui_impl_win32.o 

# === DEAR IMGUI = VALID BACKENDS ===
# allegro5 glfw    sdlgpu3
# android  glut    sdlrenderer2
# dx9      opengl2 sdlrenderer3
# dx10     opengl3 vulkan
# dx11     sdl2    wgpu
# dx12     sdl3    win32
IMGUI_ENABLE_BACKENDS := sdl3 opengl3

# Dear ImGui
IMGUI_UPSTREAM := https://github.com/ocornut/imgui.git
IMGUI_BRANCH := docking
IMGUI_TAG := v1.92.3-docking

IMGUI_BACKENDS := $(foreach backend, $(IMGUI_ENABLE_BACKENDS), imgui_impl_$(backend).o)

IMGUI_OBJS := imgui.o imgui_demo.o                        \
			  imgui_draw.o imgui_tables.o imgui_widgets.o \
			  imgui_freetype.o imgui_stdlib.o \
			  $(addprefix backends/, $(IMGUI_BACKENDS))

STATICLIBS := $(foreach dep, $(DEPS), lib$(dep).a)

# === BUILD TARGETS === 
all: $(BUILD) $(STATICLIBS)
$(BUILD):
	mkdir -p $(addprefix $(BUILD)/, $(DEPS))

libimgui.a: imgui $(addprefix $(BUILD)/imgui/, $(IMGUI_OBJS))
	ar rcs $@ $(filter %.o, $^)

$(BUILD)/imgui/imgui_stdlib.o: imgui/misc/cpp/imgui_stdlib.cpp
	$(CXX) -c $^ -o $@ -Iimgui
$(BUILD)/imgui/imgui_freetype.o: imgui/misc/freetype/imgui_freetype.cpp
	$(CXX) -c $^ -o $@ -Iimgui
$(BUILD)/imgui/backends/%.o: imgui/backends/%.cpp
	mkdir -p $(dir $@)
	$(CXX) -c $^ -o $@ -Iimgui
$(BUILD)/imgui/%.o: imgui/%.cpp
	$(CXX) -c $^ -o $@

# === SYNC TARGETS ===
.PHONY: sync $(SYNC)
sync: $(SYNC)

imgui:
	mkdir -p $@
	- git -C $@ init
	- git -C $@ remote add upstream $(IMGUI_UPSTREAM)
	$(MAKE) $@-sync
imgui-sync: imgui
	git -C $< fetch upstream --tags
	git -C $< -c advice.detachedHead=false checkout $(IMGUI_TAG)

# === UTILITY TARGETS === 
.PHONY: clean purge
clean:
	rm -rf $(BUILD) $(STATICLIBS)
purge: clean
	rm -rf $(DEPS)