# === Config ===
TARGET       := boot/espresso.bin
ISO          := boot/espresso.iso
CC           := i686-elf-gcc
AS           := i686-elf-as
NASM         := nasm
QEMU_MKE_IMG := qemu-img create -f raw espresso.img 64M
MKFS_VFAT    := sudo mkfs.vfat
MKFS_FLAGS   := -F 32 --mbr -S 512
NASMFLAGS    := -f elf32
WNOFLAGS     := -Wno-discarded-qualifiers
CFLAGS       := -std=gnu99 -ffreestanding -O2 -Wall -Wextra -msse $(WNOFLAGS)
LDFLAGS      := -T linker.ld -ffreestanding -O2 -nostdlib
QEMUFLAGS    := -device isa-debug-exit -serial stdio -kernel $(TARGET) -drive file=espresso.img,format=raw,if=ide,readonly=off,rerror=report,werror=report -cpu qemu32,sse2 #-singlestep
SRC_DIRS     := kernel drivers lib
INCLUDE_DIRS := include
INCLUDES     := $(addprefix -I, $(INCLUDE_DIRS))
ISO_DIR      := isodir
BOOT_DIR     := $(ISO_DIR)/boot
GRUB_DIR     := $(BOOT_DIR)/grub
GRUB_CFG     := grub.cfg

# === File collection ===
C_SRCS       := $(foreach dir, $(SRC_DIRS), $(shell find $(dir) -name '*.c'))
S_SRCS       := boot.s crti.s crtn.s misc_asm.s
NASM_SRCS    := gdt.asm pit.asm isr.asm
CRTI_OBJ     := crti.o
CRTBEGIN_OBJ := $(shell $(CC) $(CFLAGS) -print-file-name=crtbegin.o)
CRTEND_OBJ   := $(shell $(CC) $(CFLAGS) -print-file-name=crtend.o)
CRTN_OBJ     := crtn.o
OBJS         := $(C_SRCS:.c=.o) $(S_SRCS:.s=.o) $(NASM_SRCS:.asm=.o)

OBJ_LINK_LIST := $(CRTI_OBJ) $(CRTBEGIN_OBJ) $(OBJS) $(CRTEND_OBJ) $(CRTN_OBJ)
INTERNAL_OBJS := $(CRTI_OBJ) $(OBJS) $(CRTN_OBJ)

# === Build all targets ===
build: all iso run

# === Default target ===
all: $(TARGET)

# === Linking ===
$(TARGET): boot.o $(filter-out boot.o, $(OBJ_LINK_LIST))
	@mkdir -p $(dir $@)
	$(CC) $(LDFLAGS) -o $@ $^ -lgcc

# === Compiling C files ===
%.o: %.c
	$(CC) $(CFLAGS) $(INCLUDES) -c $< -o $@

# === Assembling S files ===
%.o: %.s
	$(AS) $< -o $@
	
%.o: %.asm
	$(NASM) $(NASMFLAGS) $< -o $@

# === ISO generation ===
iso: $(TARGET)
	@grub-file --is-x86-multiboot $(TARGET) && echo "multiboot confirmed" || (echo "not multiboot" && exit 1)
	mkdir -p $(GRUB_DIR)
	cp $(TARGET) $(BOOT_DIR)/
	cp $(GRUB_CFG) $(GRUB_DIR)/
	grub-mkrescue -o $(ISO) $(ISO_DIR)

# === Run in QEMU ===
run: iso
	$(QEMU_MKE_IMG)
	echo "\n"
	$(MKFS_VFAT) $(MKFS_FLAGS) espresso.img
	qemu-system-i386 $(QEMUFLAGS)

# === Clean all build artifacts ===
clean:
	rm -f $(INTERNAL_OBJS) $(TARGET) $(ISO)
	rm -rf $(ISO_DIR)
	rm -f espresso.img

.PHONY: all clean iso run