ASM := nasm
CC := x86_64-elf-gcc
LD := x86_64-elf-gcc
OBJDUMP := x86_64-elf-objdump
#Recursive Wildcard
rwildcard=$(foreach d,$(wildcard $1*),$(call rwildcard,$d/,$2) $(filter $(subst *,%,$2),$d))
rdircard=$(sort $(dir $(call rwildcard,$1,*)))
rdircardex=$(sort $(dir $(call rwildcard,$1,$2)))

#x64 vars
LD_SCRIPT := build/linker.ld
GRUB_CFG := build/grub.cfg

SOURCE_DIR := src
TARGET_DIR := target
HEADER_DIRS := $(call rdircardex, $(SOURCE_DIR), *.h)
ALL_TARGET_DIRS := $(addprefix $(TARGET_DIR)/,$(call rdircard, $(SOURCE_DIR)))
ASM_HEADER_DIRS := $(call rdircardex, $(SOURCE_DIR), *.inc)

C_WARNINGS := -Wall \
			  -Werror \
			  -Wextra \
			  -Wpedantic \
			  -pedantic-errors \
			  -Wdouble-promotion \
			  -Winit-self \
			  -Wmissing-include-dirs \
			  -Wswitch-default \
			  -Wunused-parameter \
			  -Wuninitialized \
			  -Wsuggest-attribute=const \
			  -Wfloat-equal \
			  -Wdeclaration-after-statement \
			  -Wtraditional-conversion \
			  -Wshadow \
			  -Wundef \
			  -Wbad-function-cast \
			  -Wc++-compat \
			  -Wcast-qual \
			  -Wcast-align \
			  -Wwrite-strings \
			  -Wconversion \
			  -Wjump-misses-init \
			  -Wlogical-op \
			  -Waggregate-return \
			  -Wno-aggressive-loop-optimizations \
			  -Wstrict-prototypes \
			  -Wold-style-definition \
			  -Wold-style-declaration \
			  -Wmissing-prototypes \
			  -Wmissing-declarations \
			  -Wredundant-decls \
			  -Wlong-long \
			  -Wvarargs \
			  -Wvla \
			  -Woverlength-strings \
			  -Wunsuffixed-float-constants \
			  -Wno-comment

C_FLAGS := -std=c11 \
		   -g \
		   -c \
		   -O2 \
		   -mcmodel=kernel \
		   -fno-exceptions \
		   -ffreestanding \
		   -mno-red-zone \
		   -mno-mmx \
		   -mno-sse \
		   -mno-sse2 \
		   -masm=intel \
		   $(C_WARNINGS) \
		   $(addprefix -I, $(HEADER_DIRS))

ASM_FLAGS := -w+all \
			 -f elf64 \
			 -F dwarf \
			 -g \
			 $(addprefix -I, $(ASM_HEADER_DIRS))

LD_FLAGS := -lgcc \
            -nodefaultlibs \
			-nostartfiles \
			-nostdlib \
			-Wl,-n \
			-Wl,--build-id=none

C_SRC := $(call rwildcard, $(SOURCE_DIR), *.c)
ASM_SRC := $(call rwildcard, $(SOURCE_DIR), *.asm)

KERNEL_ELF := kernel.elf
KERNEL_DASM := kernel.dasm
KERNEL_SYM := kernel.sym

#Object files
C_OBJ := $(C_SRC:.c=.o)
ASM_OBJ := $(ASM_SRC:.asm=.oasm)
ALL_OBJ := $(addprefix $(TARGET_DIR)/,$(C_OBJ)) $(addprefix $(TARGET_DIR)/,$(ASM_OBJ))


#Commands
all: init compile link buildiso disasm gensym

init:
	mkdir -p $(ALL_TARGET_DIRS)

compile: $(C_OBJ) $(ASM_OBJ)

link: $(KERNEL_ELF)

buildiso:
	mkdir -p $(TARGET_DIR)/temp_iso/secX
	mkdir -p $(TARGET_DIR)/temp_iso/boot
	mkdir -p $(TARGET_DIR)/temp_iso/boot/grub
	cp $(TARGET_DIR)/$(KERNEL_ELF) $(TARGET_DIR)/temp_iso/secX/$(KERNEL_ELF)
	cp $(GRUB_CFG) $(TARGET_DIR)/temp_iso/boot/grub/
	grub-mkrescue -o $(TARGET_DIR)/secX.iso $(TARGET_DIR)/temp_iso

gensym:
	nm $(TARGET_DIR)/$(KERNEL_ELF) | grep " T " | awk '{print $$1" "$$3}' > $(TARGET_DIR)/$(KERNEL_SYM)
clean:
	rm -rf $(TARGET_DIR)

%.o: %.c
	$(CC) $(C_FLAGS) -o $(TARGET_DIR)/$@ $^

%.oasm: %.asm
	$(ASM) $(ASM_FLAGS) -o $(TARGET_DIR)/$@ $^

$(KERNEL_ELF): $(ALL_OBJ)
	$(LD) $(LD_FLAGS) -T $(LD_SCRIPT) -o $(TARGET_DIR)/$(KERNEL_ELF) $(ALL_OBJ)

disasm:
	$(OBJDUMP) -M intel -D $(TARGET_DIR)/$(KERNEL_ELF) > $(TARGET_DIR)/$(KERNEL_DASM)