# https://www.gnu.org/software/make/manual/html_node/Setting.html
# :=	expanded variable, right-hand side can contain variables
# ?=	only set if it doesn't have a value
# !=	execute a shell script on the right-hand side and assign its result to the left-hand side

include toolchain.makefile
OBJ_DIR := build

include src/makefile
include libk/makefile
AS_OBJ := $(addprefix $(OBJ_DIR)/, $(AS_OBJ))
CXX_OBJ := $(addprefix $(OBJ_DIR)/, $(CXX_OBJ))
CXX_TEST_OBJ := $(addprefix $(OBJ_DIR)/, $(CXX_TEST_OBJ))
CXX_INCLUDE := $(addprefix -I, $(CXX_INCLUDE))

# $@ is target
# $< is first dependency
# $^ is all dependencies

.PHONY: default clean test check-grub run
default: glitch.elf

glitch.elf: $(AS_OBJ) $(CXX_OBJ)
	@echo "  LD  $@"
	@$(LD) $(LD_FLAGS) -o $@ $(AS_OBJ) $(CXX_OBJ)

$(AS_OBJ): $(OBJ_DIR)/%.o: %.s
	@mkdir -p $(@D)
	@echo "  AS  $^"
	@$(AS) -target $(TARGET) -nostdlib -Wall -Wextra -c $^ -o $@

$(CXX_OBJ) $(CXX_TEST_OBJ): $(OBJ_DIR)/%.o : %.cc
	@mkdir -p $(@D)
	@echo "  CXX $^"
	@$(CXX) -target $(TARGET) $(CXX_FLAGS) $(CXX_INCLUDE) -c $^ -o $@

clean:
	rm -rf $(AS_OBJ) $(CXX_OBJ) $(CXX_TEST_OBJ) glitch.elf isodir

# testing
test: $(CXX_TEST_OBJ) check-grub
check-grub: glitch.elf
	grub-file --is-x86-multiboot2 glitch.elf

# disk image
glitch.iso: glitch.elf grub/grub.cfg
	@mkdir -p isodir/boot/grub
	@cp glitch.elf isodir/boot/glitch.elf
	@cp grub/grub.cfg isodir/boot/grub/grub.cfg
	@$(BOOT) -o $@ isodir

run: glitch.iso
	@$(EMU) $<