CC = x86_64-elf-gcc
LD = x86_64-elf-ld

CFLAGS 	= -m64 -ffreestanding -fno-builtin -Wall -Wextra -Wshadow -std=c23
LDFLAGS = 

SRC_C   := src/kernel.c src/vga.c src/idt.c src/string.c src/keyboard.c
SRC_ASM := src/boot.asm src/idt_stub.asm

OBJ_C   := $(SRC_C:src/%.c=.build/%.o)
OBJ_ASM := $(SRC_ASM:src/%.asm=.build/%.o)
OBJS    := $(OBJ_C) $(OBJ_ASM)

all: .build/nub-os.iso

clean:
	@rm -r .build 2>/dev/null || true

build-dir:
	mkdir .build 2>/dev/null || true

.build/nub-os.iso: .build/kernel
	mkdir -p .build/iso/boot/grub
	cp grub.cfg .build/iso/boot/grub
	cp .build/kernel .build/iso/boot/
	grub-mkrescue -o .build/nub-os.iso .build/iso/

.build/kernel: $(OBJS)
	$(LD) $(LDFLAGS) -T src/boot.ld -o $@ $^

.build/%.o: src/%.c | build-dir
	$(CC) $(CFLAGS) -c -o $@ $<

.build/%.o: src/%.asm | build-dir
	nasm -f elf64 -o $@ $<