BUILD_DIR     ?= build
DEPS_DIR      ?= $(BUILD_DIR)/deps
TEST_DIR      ?= tests
INCLUDE_DIR   := include

MODE          ?= debug

RELEASE_OPT   ?= 3
CLINE_SIZE    ?= 64

CXX           ?= clang++
AR            ?= ar
ARFLAGS       := rcs

TESTS := $(shell find $(TEST_DIR) -name '*.cc')

TEST_BINS := $(patsubst $(TEST_DIR)/%.cc,$(BUILD_DIR)/tests/%,$(TESTS))
TEST_DEPS := $(patsubst $(TEST_DIR)/%.cc,$(DEPS_DIR)/tests/%.d,$(TESTS))

INCLUDES := $(addprefix -I,$(INCLUDE_DIR))

WARN_FLAGS := \
	-Wall \
	-Wextra \
	-Wpedantic \
	-Werror

COMMON_CXXFLAGS := \
	-std=c++20 \
	-flto \
	--param=destructive-interference-size=$(CLINE_SIZE) \
	$(WARN_FLAGS) \
	$(INCLUDES)

DEBUG_CXXFLAGS := \
	-O0 \
	-g \
	-fsanitize=thread \
	-fno-omit-frame-pointer

RELEASE_CXXFLAGS := \
	-O$(RELEASE_OPT) \
	-DNDEBUG

ifeq ($(MODE),debug)
	CXXFLAGS := $(COMMON_CXXFLAGS) $(DEBUG_CXXFLAGS)
else ifeq ($(MODE),release)
	CXXFLAGS := $(COMMON_CXXFLAGS) $(RELEASE_CXXFLAGS)
else
	$(error Unknown MODE '$(MODE)'; use MODE=debug or MODE=release)
endif

.PHONY: all clean tests

all: tests
tests: $(TEST_BINS)

$(BUILD_DIR)/tests/%: $(TEST_DIR)/%.cc
	@mkdir -p $(dir $@)
	@mkdir -p $(DEPS_DIR)/tests/$(dir $*)
	$(CXX) $(CXXFLAGS) -MMD -MP -MF $(DEPS_DIR)/tests/$*.d $< -o $@

clean:
	rm -rf $(BUILD_DIR)

-include $(TEST_DEPS)