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

LIB_FILENAME ?= libvieter.a

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

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

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 -Wall -Werror -Wextra
CFLAGS += $(INC_FLAGS)

.PHONY: all
all: vieter


# =====COMPILATION=====
.PHONY: vieter
vieter: $(BUILD_DIR)/$(LIB_FILENAME)
$(BUILD_DIR)/$(LIB_FILENAME): $(OBJS)
	ar -rcs $@ $(OBJS)

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


# =====TESTING=====
.PHONY: test
test: build-test
	@ $(foreach bin,$(BINS_TEST),./$(bin);)

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

# For simplicity, we link every object file to each of the test files. This
# might be changed later if this starts to become too slow.
$(BINS_TEST): %: %.c.o $(OBJS)
	$(CC) $^ -o $@

# Each test includes the test directory, which contains the acutest header file
$(BUILD_DIR)/$(TEST_DIR)/%.c.o: $(TEST_DIR)/%.c
	mkdir -p $(dir $@)
	$(CC) $(CFLAGS) -I$(TEST_DIR) -c $< -o $@

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

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

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


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