NDK_ROOT := $(shell dirname $(CC))/../../../../..

ifeq "$(findstring 64, $(ARCH))" "64"
	# lowest 64-bit API level
	API_LEVEL := 21
else ifeq "$(ARCH)" "i386"
	# clone(2) declaration is present only since this api level
	API_LEVEL := 17
else
	# lowest supported 32-bit API level
	API_LEVEL := 16
endif

ifeq "$(ARCH)" "arm"
	SYSROOT_ARCH := arm
	STL_ARCH := armeabi-v7a
	TRIPLE := armv7-none-linux-androideabi
	ARCH_CFLAGS += -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -marm
else ifeq "$(ARCH)" "aarch64"
	SYSROOT_ARCH := arm64
	STL_ARCH := arm64-v8a
	TRIPLE := aarch64-none-linux-android
else ifeq "$(ARCH)" "i386"
	SYSROOT_ARCH := x86
	STL_ARCH := x86
	TRIPLE := i686-none-linux-android
else
	SYSROOT_ARCH := $(ARCH)
	STL_ARCH := $(ARCH)
	TRIPLE := $(ARCH)-none-linux-android
endif

ifeq "$(findstring 86,$(ARCH))" "86"
	TOOLCHAIN_DIR := $(STL_ARCH)-4.9
else ifeq "$(ARCH)" "arm"
	TOOLCHAIN_DIR := arm-linux-androideabi-4.9
else
	TOOLCHAIN_DIR := $(subst -none,,$(TRIPLE))-4.9
endif

ifeq "$(ARCH)" "arm"
	TOOL_PREFIX := arm-linux-androideabi
else
	TOOL_PREFIX := $(subst -none,,$(TRIPLE))
endif

ifeq "$(HOST_OS)" "Linux"
	HOST_TAG := linux-x86_64
else ifeq "$(HOST_OS)" "Darwin"
	HOST_TAG := darwin-x86_64
else
	HOST_TAG := windows-x86_64
endif

GCC_TOOLCHAIN = $(NDK_ROOT)/toolchains/$(TOOLCHAIN_DIR)/prebuilt/$(HOST_TAG)

OBJCOPY ?= $(GCC_TOOLCHAIN)/bin/$(TOOL_PREFIX)-objcopy
ARCHIVER ?= $(GCC_TOOLCHAIN)/bin/$(TOOL_PREFIX)-ar

ifeq "$(findstring clang,$(CC))" "clang"
	ARCH_CFLAGS += -target $(TRIPLE) --gcc-toolchain=$(GCC_TOOLCHAIN)
	ARCH_LDFLAGS += -target $(TRIPLE) --gcc-toolchain=$(GCC_TOOLCHAIN)
endif

ARCH_CFLAGS += --sysroot=$(NDK_ROOT)/sysroot \
	-isystem $(NDK_ROOT)/sysroot/usr/include/$(TOOL_PREFIX) \
	-D__ANDROID_API__=$(API_LEVEL) \
	-isystem $(NDK_ROOT)/platforms/android-$(API_LEVEL)/arch-$(SYSROOT_ARCH)/usr/include

ARCH_LDFLAGS += --sysroot=$(NDK_ROOT)/platforms/android-$(API_LEVEL)/arch-$(SYSROOT_ARCH) -lm

ARCH_CXXFLAGS += \
	-isystem $(NDK_ROOT)/sources/cxx-stl/llvm-libc++/include \
	-isystem $(NDK_ROOT)/sources/android/support/include \
	-isystem $(NDK_ROOT)/sources/cxx-stl/llvm-libc++abi/include

ARCH_LDFLAGS += \
	-L$(NDK_ROOT)/sources/cxx-stl/llvm-libc++/libs/$(STL_ARCH) \
	$(NDK_ROOT)/sources/cxx-stl/llvm-libc++/libs/$(STL_ARCH)/libc++_static.a \
	-lc++abi \
	-nostdlib++