CROSS_COMPILE ?=

TARGET_FILE ?= test_c

CC = $(CROSS_COMPILE)gcc
CPP = $(CROSS_COMPILE)cpp
CHECK = cppcheck
LCOV = lcov
GENHTML = genhtml

SRC_DIR = src
OBJ_DIR = obj
BIN_DIR = bin
COVERAGE_DIR = coverage
UNIT_TEST_SRC_DIR = test/unit
UNIT_TEST_OBJ_DIR = $(OBJ_DIR)/$(UNIT_TEST_SRC_DIR)

PREFIX ?= /usr
BIN_INSTALL_DIR = $(PREFIX)/bin

INCLUDES := interface/
INCLUDES += include/
INCLUDES += include/$(ARCH)/
INCLUDES += $(PREFIX)/include/
INCLUDES += $(EXTRA_INC)

LIBS =

LD_FLAGS += $(addprefix -L,$(EXTRA_LIB_DIR))
LD_FLAGS += -lm

ifneq "$(findstring $(MAKECMDGOALS), build_unit_test exec_unit_test coverage)" ""
INCLUDES += test/inc
C_FLAGS += --coverage
LD_FLAGS += --coverage
endif

C_FLAGS += -fpic

C_FLAGS += -O0 -ggdb3 -Wall
CPP_FLAGS += $(addprefix -I, $(INCLUDES))

CHECK_FLAGS = $(addprefix -I,$(filter-out $(PREFIX)/include/,$(INCLUDES)))
CHECK_FLAGS += --enable=all --template=gcc --error-exitcode=1 --suppress=missingIncludeSystem --inline-suppr --force

C_SRCS = $(wildcard $(SRC_DIR)/*.c)
C_SRCS += $(wildcard $(SRC_DIR)/$(ARCH)/*.c)
C_OBJS = $(patsubst $(SRC_DIR)%,$(OBJ_DIR)%,$(patsubst %.c,%.o,$(C_SRCS)))

UNIT_TEST_SRCS = $(wildcard $(UNIT_TEST_SRC_DIR)/*.c) $(filter-out %main.c,$(CC_SRCS))
UNIT_TEST_OBJS = $(patsubst $(SRC_DIR)%,$(OBJ_DIR)%,$(patsubst $(UNIT_TEST_SRC_DIR)%,$(UNIT_TEST_OBJ_DIR)%,$(patsubst %.c,%.o,$(UNIT_TEST_SRCS))))

OBJS = $(C_OBJS)

UNIT_TEST_TARGET = $(BIN_DIR)/$(UNIT_TEST_SRC_DIR)/$(TARGET_FILE)
TARGET = $(BIN_DIR)/$(TARGET_FILE)
THIS_MAKEFILE := $(lastword $(MAKEFILE_LIST))

.PHONY: all install uninstall clean distclean debug
debug:
	@echo $(C_SRCS)
	@echo $(C_OBJS)
	@echo $(ARCH)
	@echo $(CPP_FLAGS)

all: $(TARGET)

install: all
	install -d $(BIN_INSTALL_DIR)
	install -m 0666 $(TARGET) $(BIN_INSTALL_DIR)

uninstall:
	rm -f $(BIN_INSTALL_DIR)/$(TARGET_FILE)

clean:
	rm -f $(TARGET)
	rm -f $(OBJS) $(patsubst %.o,%.d,$(OBJS))
	rm -f $(UNIT_TEST_OBJS) $(patsubst %.o,%.d,$(UNIT_TEST_OBJS)) $(UNIT_TEST_TARGET)
	rm -f $(UNIT_TEST_OBJ_DIR)/*.gcda
	rm -f $(UNIT_TEST_OBJ_DIR)/*.gcno
	rm -f $(OBJ_DIR)/*.gcda $(OBJ_DIR)/*.gcno
	rm -fr $(COVERAGE_DIR)

distclean:
	rm -rf $(OBJ_DIR) $(BIN_DIR) $(COVERAGE_DIR)

.PHONY: coverage
coverage: _cov_genhtml
	$(eval COVERAGE:=$(shell grep 'lines' .coverage.tmp | egrep -o '[0-9]+.[0-9]+%'))
	@echo
	@echo Line coverage: $(COVERAGE)
	@echo
	@rm -f .coverage.tmp

.PHONY: _cov_lcov
_cov_lcov: exec_unit_test
	@rm -f $(UNIT_TEST_OBJ_DIR)/*.gcda
	@rm -f $(UNIT_TEST_OBJ_DIR)/*.gcno
	@mkdir -p $(COVERAGE_DIR)
	$(LCOV) -c -d $(OBJ_DIR) -o $(COVERAGE_DIR)/coverage.info

.PHONY: _cov_genhtml
_cov_genhtml: _cov_lcov
	$(GENHTML) -o $(COVERAGE_DIR)/html $(COVERAGE_DIR)/coverage.info > .coverage.tmp

.PHONY: unit_test
build_unit_test: $(UNIT_TEST_TARGET)

.PHONY: unit_test
exec_unit_test: $(UNIT_TEST_TARGET)
	$(UNIT_TEST_TARGET)

.PHONY: check
check: $(CC_SRCS)
	$(CHECK) $(CHECK_FLAGS) $(CC_SRCS)

$(UNIT_TEST_TARGET): $(UNIT_TEST_OBJS) $(THIS_MAKEFILE)
	@mkdir -p $(BIN_DIR)/$(UNIT_TEST_SRC_DIR)
	$(CC) $(C_FLAGS) $(LD_FLAGS) $(UNIT_TEST_OBJS) -o $@

$(TARGET): $(OBJS) $(THIS_MAKEFILE)
	@mkdir -p $(BIN_DIR)
	$(CC) $(C_FLAGS) $(LD_FLAGS) $(OBJS) $(addprefix -l,$(LIBS)) -o $@

.PRECIOUS: $(OBJ_DIR)/%.d
$(OBJ_DIR)/%.d: $(SRC_DIR)/%.c
	@mkdir -p $(OBJ_DIR)/$(ARCH)
	$(CPP) -MM -MF $@ -MP -MT $(patsubst %.d,%.o,$@) $(CPP_FLAGS) $(patsubst $(OBJ_DIR)/%.d,$(SRC_DIR)/%.c,$@)

.PRECIOUS: $(UNIT_TEST_OBJ_DIR)/%.d
$(UNIT_TEST_OBJ_DIR)/%.d: $(UNIT_TEST_SRC_DIR)/%.c
	@mkdir -p $(UNIT_TEST_OBJ_DIR)
	$(CPP) -MM -MF $@ -MP -MT $(patsubst %.d,%.o,$@) $(CPP_FLAGS) $(patsubst $(UNIT_TEST_OBJ_DIR)/%.d,$(UNIT_TEST_SRC_DIR)/%.c,$@)

$(OBJ_DIR)/%.o: $(SRC_DIR)/%.c $(OBJ_DIR)/%.d
	@mkdir -p $(OBJ_DIR)/$(ARCH)
	$(CC) -c $(CPP_FLAGS) $(C_FLAGS) $< -o $@

$(UNIT_TEST_OBJ_DIR)/%.o: $(UNIT_TEST_SRC_DIR)/%.c $(UNIT_TEST_OBJ_DIR)/%.d
	@mkdir -p $(UNIT_TEST_OBJ_DIR)
	$(CC) -c $(CPP_FLAGS) $(C_FLAGS) $< -o $@

ifneq ($(MAKECMDGOALS),clean)
-include $(patsubst %.o,%.d,$(OBJS))
endif