# https://spin.atomicobject.com/2016/08/26/makefile-c-projects/ was a great
# base for this Makefile

LIB_FILENAME ?= libtrie.a

BUILD_DIR ?= build
SRC_DIR ?= src
TEST_DIR ?= test
INC_DIRS ?= include

LIB := $(BUILD_DIR)/$(LIB_FILENAME)

SRCS != find '$(SRC_DIR)' -iname '*.c'
SRCS_H != find $(INC_DIRS) -iname '*.h'
SRCS_H_INTERNAL != find $(SRC_DIR) -iname '*.h'
SRCS_TEST != find '$(TEST_DIR)' -iname '*.c'

OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
OBJS_TEST := $(SRCS_TEST:%=$(BUILD_DIR)/%.o)
DEPS := $(SRCS:%=$(BUILD_DIR)/%.d) $(SRCS_TEST:%=$(BUILD_DIR)/%.d)

BINS_TEST := $(OBJS_TEST:%.c.o=%)
TARGETS_TEST := $(BINS_TEST:%=test-%)
TARGETS_MEM_TEST := $(BINS_TEST:%=test-mem-%)

INC_FLAGS := $(addprefix -I,$(INC_DIRS))

# -MMD: generate a .d file for every source file. This file can be imported by
#  make and makes make aware that a header file has been changed, ensuring an
#  object file is also recompiled if only a header is changed.
# -MP: generate a dummy target for every header file (according to the  docs it
#  prevents some errors when removing header files)
CFLAGS ?= -MMD -MP -g
_CFLAGS := $(INC_FLAGS) $(CFLAGS) -Wall -Wextra

.PHONY: all
all: lib


# =====COMPILATION=====
# Utility used by the CI to lint
.PHONY: objs
objs: $(OBJS)

.PHONY: lib
lib: $(LIB)
$(LIB): $(OBJS)
	ar -rcs $@ $(OBJS)

$(BUILD_DIR)/$(SRC_DIR)/%.c.o: $(SRC_DIR)/%.c
	mkdir -p $(dir $@)
	$(CC) -c $(_CFLAGS) $< -o $@


# =====TESTING=====
.PHONY: test
test: $(TARGETS_TEST)

.PHONY: test-mem
test-mem: $(TARGETS_MEM_TEST)

.PHONY: $(TARGETS_TEST)
$(TARGETS_TEST): test-%: %
	./$^

.PHONY: $(TARGETS_MEM_TEST)
$(TARGETS_MEM_TEST): test-mem-%: %
	valgrind --tool=memcheck --error-exitcode=1 --track-origins=yes --leak-check=full ./$^

.PHONY: build-test
build-test: $(BINS_TEST)

$(BINS_TEST): %: %.c.o $(LIB)
	$(CC) \
		$^ -o $@

# Along with the include directory, each test includes $(TEST_DIR) (which
# contains the acutest.h header file), and the src directory of the module it's
# testing. This allows tests to access internal methods, which aren't publicly
# exposed.
$(BUILD_DIR)/$(TEST_DIR)/%.c.o: $(TEST_DIR)/%.c
	mkdir -p $(dir $@)
	$(CC) $(_CFLAGS) -I$(TEST_DIR) \
		-I$(dir $(@:$(BUILD_DIR)/$(TEST_DIR)/%=$(SRC_DIR)/%)) \
		-c $< -o $@

# =====MAINTENANCE=====
.PHONY: lint
lint:
	clang-format -n --Werror $(SRCS) $(SRCS_H) $(SRCS_H_INTERNAL)

.PHONY: fmt
fmt:
	clang-format -i $(SRCS) $(SRCS_H) $(SRCS_H_INTERNAL)

.PHONY: clean
clean:
	rm -rf $(BUILD_DIR)


.PHONY: bear
bear: clean
	bear -- make
	bear --append -- make build-test


# Make make aware of the .d files
-include $(DEPS)