CC ?= cc
CXX ?= c++
PKG_CONFIG ?= pkg-config
FLTK_CONFIG ?= fltk-config
BUILD_DIR ?= build
PREFIX ?= /usr/local

CFLAGS ?= -O2 -g
CFLAGS += -std=c99 -Wall -Wextra -Wpedantic -Wconversion -Wshadow -Iinclude
CXXFLAGS ?= -O2 -g
CXXFLAGS += -std=c++17 -Wall -Wextra -Wpedantic -Iinclude
LDFLAGS ?=

CORE_SOURCES := src/core/xtc.c src/graph/graph.c src/dsp/gain.c src/engine/offline_engine.c
CORE_OBJECTS := $(CORE_SOURCES:%.c=$(BUILD_DIR)/%.o)
TEST_OBJECT := $(BUILD_DIR)/tests/unit/test_core.o
ifeq ($(shell $(PKG_CONFIG) --exists fltk 2>/dev/null && echo yes),yes)
FLTK_CXXFLAGS := $(shell $(PKG_CONFIG) --cflags fltk)
FLTK_LIBS := $(shell $(PKG_CONFIG) --libs fltk)
GUI_AVAILABLE := yes
else ifeq ($(shell $(FLTK_CONFIG) --version >/dev/null 2>&1 && echo yes),yes)
FLTK_CXXFLAGS := $(shell $(FLTK_CONFIG) --cxxflags)
FLTK_LIBS := $(shell $(FLTK_CONFIG) --ldflags)
GUI_AVAILABLE := yes
endif

.PHONY: all clean test debug gui install
all: $(BUILD_DIR)/libxtc.a $(BUILD_DIR)/xtc-check

$(BUILD_DIR)/xtc-check: $(BUILD_DIR)/src/main.o $(BUILD_DIR)/libxtc.a
	$(CC) $(LDFLAGS) -o $@ $^ -lm

$(BUILD_DIR)/libxtc.a: $(CORE_OBJECTS)
	@mkdir -p $(@D)
	$(AR) rcs $@ $^

$(BUILD_DIR)/%.o: %.c
	@mkdir -p $(@D)
	$(CC) $(CFLAGS) -MMD -MP -c $< -o $@

$(BUILD_DIR)/%.o: %.cpp
	@mkdir -p $(@D)
	$(CXX) $(CXXFLAGS) $(FLTK_CXXFLAGS) -MMD -MP -c $< -o $@

$(TEST_OBJECT): tests/unit/test_core.c
	@mkdir -p $(@D)
	$(CC) $(CFLAGS) -MMD -MP -c $< -o $@

$(BUILD_DIR)/test_core: $(TEST_OBJECT) $(BUILD_DIR)/libxtc.a
	$(CC) $(LDFLAGS) -o $@ $(TEST_OBJECT) $(BUILD_DIR)/libxtc.a -lm

$(BUILD_DIR)/test_offline: $(BUILD_DIR)/tests/unit/test_offline.o $(BUILD_DIR)/libxtc.a
	$(CC) $(LDFLAGS) -o $@ $^ -lm

test: $(BUILD_DIR)/test_core $(BUILD_DIR)/test_offline $(BUILD_DIR)/xtc-check
	./$(BUILD_DIR)/test_core
	./$(BUILD_DIR)/test_offline
	./$(BUILD_DIR)/xtc-check

debug:
	$(MAKE) BUILD_DIR="$(BUILD_DIR)/debug" CFLAGS="$(CFLAGS) -O0 -g3" CXXFLAGS="$(CXXFLAGS) -O0 -g3" all test

ifeq ($(GUI_AVAILABLE),yes)
gui: $(BUILD_DIR)/xtc

$(BUILD_DIR)/xtc: $(BUILD_DIR)/src/gui/main.o $(BUILD_DIR)/src/gui/main_window.o $(BUILD_DIR)/libxtc.a
	$(CXX) $(LDFLAGS) -o $@ $^ $(FLTK_LIBS) -lm
else
gui:
	@echo "FLTK was not found by pkg-config or fltk-config. GUI requires FLTK development files."
	@exit 1
endif

install: all
	install -d "$(DESTDIR)$(PREFIX)/include/xtc" "$(DESTDIR)$(PREFIX)/lib"
	install -m 0644 include/xtc/*.h "$(DESTDIR)$(PREFIX)/include/xtc/"
	install -m 0644 "$(BUILD_DIR)/libxtc.a" "$(DESTDIR)$(PREFIX)/lib/"

clean:
	rm -rf "$(BUILD_DIR)"

-include $(CORE_OBJECTS:.o=.d) $(TEST_OBJECT:.o=.d) $(BUILD_DIR)/src/main.d $(BUILD_DIR)/tests/unit/test_offline.d \
    $(BUILD_DIR)/src/gui/main.d $(BUILD_DIR)/src/gui/main_window.d