ifeq (, $(__RIOTBUILD_FLAG))
    $(error You cannot build a module on its own. Use "make" in your application's directory instead.)
endif

unexport DIRS
DIRS := $(sort $(abspath ${DIRS}))

MODULE ?= $(shell basename $(CURDIR))

.PHONY: all ${DIRS:%=ALL--%} ${DIRS:%=CLEAN--%}

all: $(BINDIR)/$(MODULE).a ..nothing

..nothing:
	@:

clean:: ${DIRS:%=CLEAN--%}

${DIRS:%=ALL--%}:
	$(QQ)"$(MAKE)" -C ${@:ALL--%=%}

${DIRS:%=CLEAN--%}:
	$(QQ)"$(MAKE)" -C ${@:CLEAN--%=%} clean

## submodules
ifeq (1, $(SUBMODULES))
    # don't use *.c as SRC if SRC is empty (e.g., no module selected)
    NO_AUTO_SRC := 1

    # allow different submodule basename (e.g., MODULE=cpu_periph_common, but match just periph_%)
    BASE_MODULE ?= $(MODULE)

    # for each $(BASE_MODULE)_<name> in USEMODULE, add <name>.c to SRC
    SRC += $(patsubst $(BASE_MODULE)_%,%.c,$(filter $(BASE_MODULE)_%,$(USEMODULE)))

    # don't fail if a selected *.c file does not exist
    ifeq (1, $(SUBMODULES_NOFORCE))
        SRC := $(filter $(SRC), $(wildcard *.c))
    endif
endif

ifeq ($(strip $(SRC))$(NO_AUTO_SRC),)
    SRC := $(filter-out $(SRC_NOLTO), $(wildcard *.c))
endif
ifeq ($(strip $(SRCXX))$(NO_AUTO_SRC),)
    SRCXX := $(wildcard *.cpp)
endif
ifeq ($(strip $(ASMSRC))$(NO_AUTO_SRC),)
    ASMSRC := $(wildcard *.s)
endif
ifeq ($(strip $(ASSMSRC))$(NO_AUTO_SRC),)
    ASSMSRC := $(wildcard *.S)
endif

OBJC_LTO    := $(SRC:%.c=$(BINDIR)/$(MODULE)/%.o)
OBJC_NOLTO  := $(SRC_NOLTO:%.c=$(BINDIR)/$(MODULE)/%.o)
OBJC        := $(OBJC_NOLTO) $(OBJC_LTO)
OBJCXX      := $(SRCXX:%.cpp=$(BINDIR)/$(MODULE)/%.o)
ASMOBJ      := $(ASMSRC:%.s=$(BINDIR)/$(MODULE)/%.o)
ASSMOBJ     := $(ASSMSRC:%.S=$(BINDIR)/$(MODULE)/%.o)

OBJ := $(OBJC) $(OBJCXX) $(ASMOBJ) $(ASSMOBJ)
DEP := $(OBJC:.o=.d) $(OBJCXX:.o=.d) $(ASSMOBJ:.o=.d)

$(BINDIR)/$(MODULE)/:
	$(Q)mkdir -p $@

$(BINDIR)/$(MODULE).a $(OBJ): | $(BINDIR)/$(MODULE)/

$(BINDIR)/$(MODULE).a: $(OBJ) | ${DIRS:%=ALL--%}
	$(Q)$(AR) $(ARFLAGS) $@ $?

CXXFLAGS = $(filter-out $(CXXUWFLAGS), $(CFLAGS)) $(CXXEXFLAGS)
CCASFLAGS = $(filter-out $(CCASUWFLAGS), $(CFLAGS)) $(CCASEXFLAGS)

# compile and generate dependency info

$(OBJC_LTO): CFLAGS+=$(LTOFLAGS)

$(OBJC): $(BINDIR)/$(MODULE)/%.o: %.c $(RIOTBUILD_CONFIG_HEADER_C)
	$(Q)$(CCACHE) $(CC) \
		-DRIOT_FILE_RELATIVE=\"$(patsubst $(RIOTBASE)/%,%,$(abspath $<))\" \
		-DRIOT_FILE_NOPATH=\"$(notdir $<)\" \
		$(CFLAGS) $(INCLUDES) -MD -MP -c -o $@ $(abspath $<)

$(OBJCXX): $(BINDIR)/$(MODULE)/%.o: %.cpp $(RIOTBUILD_CONFIG_HEADER_C)
	$(Q)$(CCACHE) $(CXX) \
		-DRIOT_FILE_RELATIVE=\"$(patsubst $(RIOTBASE)/%,%,$(abspath $<))\" \
		-DRIOT_FILE_NOPATH=\"$(notdir $<)\" \
		$(CXXFLAGS) $(CXXINCLUDES) $(INCLUDES) -MD -MP -c -o $@ $(abspath $<)

$(ASMOBJ): $(BINDIR)/$(MODULE)/%.o: %.s
	$(Q)$(AS) $(ASFLAGS) -o $@ $(abspath $<)

$(ASSMOBJ): $(BINDIR)/$(MODULE)/%.o: %.S
	$(Q)$(CCAS) $(CCASFLAGS) $(INCLUDES) -MD -MP -c -o $@ $(abspath $<)

# pull in dependency info for *existing* .o files
# deleted header files will be silently ignored
-include $(DEP)