export
ARCH ?= x86_64
DEBUG ?= 1
RUST_LIB_PATH=debug
CARGO_FLAGS =
#QEMU_DEBUG=-d int -no-reboot -no-shutdown
TARGET=kernel.iso

ifeq ($(DEBUG), 0)
	RUST_LIB_PATH=release
	CARGO_FLAGS=--release
endif

ifeq ($(ARCH), x86)
	QEMU = qemu-system-i386
	QEMU_OPTS = -serial file:serial.log
	MACHINE = -machine q35
	BOOT = -cdrom kernel.iso
	ARCH_PREFIX = i386-elf-
	target = "./arch/x86.json"
	RUST_OBJS = ../target/x86/$(RUST_LIB_PATH)/libmyrustkernel.a
	ASM_PATHS = ./arch/x86/boot
	ASM_PATHS += ./arch/x86/common/boot
	CARGO_B = --target "./arch/x86.json"
	LD_SCRIPT=../arch/x86.ld
endif

ifeq ($(ARCH), x86_64)
	QEMU = qemu-system-x86_64
	QEMU_OPTS = -serial file:serial.log
	MACHINE = -machine q35
	BOOT = -cdrom kernel.iso
	ARCH_PREFIX = x86_64-elf-
	target = "./arch/x86_64.json"
	RUST_OBJS = ../target/x86_64/$(RUST_LIB_PATH)/libmyrustkernel.a
	ASM_PATHS = ./arch/x86_64/boot
	ASM_PATHS += ./arch/x86/common/boot
	CARGO_B = --target "./arch/x86_64.json"
	LD_SCRIPT=../arch/x86_64.ld
endif

ifeq ($(ARCH), riscv64)
	QEMU = qemu-system-riscv64
	QEMU_OPTS = -nographic -serial mon:stdio
	MACHINE = -machine virt -bios none
	BOOT = -kernel ./src/kernel.bin
	ARCH_PREFIX = riscv64-elf-
	target = "./arch/riscv64.json"
	RUST_OBJS = ../target/riscv64/$(RUST_LIB_PATH)/libmyrustkernel.a
	ASM_PATHS = ./arch/riscv64/boot
	CARGO_B = --target "./arch/riscv64.json"
	LD_SCRIPT=../arch/riscv64.ld
	TARGET=src/kernel.bin
endif

ifndef ARCH_PREFIX
$(error ARCH available: "x86_64", "x86", "riscv64")
endif

CC = $(ARCH_PREFIX)gcc
AS = $(ARCH_PREFIX)as
LD = $(ARCH_PREFIX)ld
OBJDUMP = $(ARCH_PREFIX)objcopy
OBJCOPY = $(ARCH_PREFIX)objdump

W := -Wall -Werror -Wextra -Wshadow -Wcast-align
# W:= -Wpointer-arith -pedantic -Wmissing-prototypes -Wmissing-declarations
W += -Wwrite-strings -Wredundant-decls -Wnested-externs -Winline -Wno-long-long
W += -Wconversion -Wstrict-prototypes
WNO := -Wno-error=unused-parameter -Wno-error=unused-variable
WNO += -Wno-error=unused-but-set-variable -Wno-error=unused-but-set-parameter
WNO += -Wno-error=infinite-recursion

CFLAGS = $(W) $(WNO) -fno-omit-frame-pointer
CFLAGS += -MD -O3 -ffreestanding -nostdlib -std=gnu89
CFLAGS += -fno-common -fno-stack-protector
CFLAGS += -fno-pie -no-pie -fno-pic
CFLAGS += -g -fsanitize=undefined
#CFLAGS += -fstack-protector-all
LDFLAGS = -z max-page-size=4096

ifeq ($(ARCH), x86)
	CFLAGS += -mgeneral-regs-only
endif

ifeq ($(ARCH), x86_64)
	CFLAGS += -mcmodel=large
	CFLAGS += -mgeneral-regs-only
endif

ifeq ($(ARCH), riscv64)
	CFLAGS += -mcmodel=medany
endif

MAKE:=$(MAKE) -s

all: $(TARGET)

FORCE:

src/kernel.bin: FORCE
	cargo b $(CARGO_B) $(CARGO_FLAGS)
	@rm -f src/kernel.bin
	@$(MAKE) -C $(@D)

isodir:
	$(info [all] $@)
	@mkdir -p isodir/boot/grub
	@cp src/grub.cfg isodir/boot/grub/grub.cfg
	@mkdir -p isodir/modules
	@dd if=/dev/zero of=isodir/modules/ext2.img bs=4M count=2 > /dev/null 2>&1
	@mkfs.ext2 isodir/modules/ext2.img > /dev/null 2>&1

kernel.iso: src/kernel.bin src/grub.cfg Makefile isodir FORCE
	$(info [all] $@)
	@cp src/kernel.bin isodir/boot/kernel.bin
	@sudo cp src/kernel.bin /srv/tftp/boot/kernel.bin
	@grub-mkrescue -o kernel.iso isodir > /dev/null 2>&1


.PHONY: all build qemu bochs mount umount clean

BOCHS = bochs -q

qemu: kernel.iso
	$(QEMU) $(MACHINE) $(BOOT) $(QEMU_OPTS) $(QEMU_DEBUG)
	@cat serial.log

bochs: kernel.iso
	@$(BOCHS) -qf .bochsrc
	@cat serial.log

mount: isodir
ifeq ("$(wildcard /mnt/ext2/lost+found/)","")
	$(info [all] $@)
	@doas mount isodir/modules/ext2.img /mnt/ext2 -o loop
	@doas chown -R aleksa:aleksa /mnt/ext2
endif

umount:
ifneq ("$(wildcard /mnt/ext2/lost+found/)","")
	$(info [all] $@)
	@doas umount /mnt/ext2
endif

clean:
	@find ./src/ -name "*.o" -exec rm {} \;
	@find ./src/ -name "*.d" -exec rm {} \;
	@rm -f kernel.iso src/kernel.bin xbochs.log bx_enh_dbg.ini log serial.log
	@rm -rf isodir
	@cargo clean
	@$(MAKE) umount