MAKEFILE_DIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))

BUILD_DIR ?= $(MAKEFILE_DIR)build
ARCH ?= x86
KERNEL_FILE_NAME ?= bzImage

KERNEL_PATH = $(BUILD_DIR)/arch/$(ARCH)/boot/$(bzImage)
KERNEL_BUILD_DIR=$(BUILD_DIR)/linux/kernel

BUSYBOX_BUILD_DIR=$(BUILD_DIR)/linux/busybox
BUSYBOX_BUILD_FILE=$(BUSYBOX_BUILD_DIR)/busybox

INITRAMFS_DIR=$(BUILD_DIR)/linux/initramfs
INITRAMFS_FILE_TMP=$(BUILD_DIR)/linux/initramfs.cpio
INITRAMFS_FILE=$(BUILD_DIR)/linux/initramfs.cpio.gz



.PHONY: initramfs initramfs_initiial initramfs_clean busybox all kernel __busybox_install

all:  $(INITRAMFS_FILE)
initramfs:initramfs_clean initramfs_initiial __busybox_install $(INITRAMFS_FILE)
kernel: $(KERNEL_PATH)
busybox: $(BUSYBOX_BUILD_FILE)

$(KERNEL_PATH):
	@mkdir -p $(KERNEL_BUILD_DIR)
	$(MAKE) -C $(MAKEFILE_DIR)/kernel O=$(KERNEL_BUILD_DIR) KCONFIG_CONFIG="$(MAKEFILE_DIR)/.kernel-config"

kernel-config:
	$(MAKE) -C $(MAKEFILE_DIR)/kernel O=$(KERNEL_BUILD_DIR) KCONFIG_CONFIG="$(MAKEFILE_DIR)/.kernel-config" menuconfig

$(BUSYBOX_BUILD_FILE):
	@mkdir -p $(BUSYBOX_BUILD_DIR)
	cp $(MAKEFILE_DIR)/.busybox-config $(BUSYBOX_BUILD_DIR)/.config
	$(MAKE) -C $(MAKEFILE_DIR)/busybox O=$(BUSYBOX_BUILD_DIR) KCONFIG_CONFIG="$(MAKEFILE_DIR)/.busybox-config"

__busybox_install:
	$(MAKE) -C $(MAKEFILE_DIR)/busybox O=$(BUSYBOX_BUILD_DIR) KCONFIG_CONFIG="$(MAKEFILE_DIR)/.busybox-config" CONFIG_PREFIX=$(INITRAMFS_DIR) install 



$(INITRAMFS_FILE): initramfs_clean initramfs_initiial __busybox_install
	find $(INITRAMFS_DIR) | cpio -o -H newc > $(INITRAMFS_FILE_TMP)
	# gzip -f $(INITRAMFS_FILE_TMP)

initramfs_clean:
	@rm -rf $(INITRAMFS_DIR)

initramfs_initiial: #$(BUSYBOX_BUILD_FILE)
	mkdir -p $(INITRAMFS_DIR)
	mkdir -p $(INITRAMFS_DIR)/{etc,mnt,proc,run,srv,tmp,var,boot,dev,home,media,opt,root,sbin,sys,usr/bin,usr/lib}

	bash -c "pushd $(INITRAMFS_DIR); ln -s usr/bin bin; popd"
	bash -c "pushd $(INITRAMFS_DIR); ln -s usr/lib lib; popd"


	echo "#!/bin/sh" >> $(INITRAMFS_DIR)/init
	echo "mount -t proc none /proc" >> $(INITRAMFS_DIR)/init
	echo "mount -t sysfs none /sys" >> $(INITRAMFS_DIR)/init
	echo "echo 'Successfully booted'" >> $(INITRAMFS_DIR)/init
	echo "exec /bin/sh" >> $(INITRAMFS_DIR)/init

	chmod +x $(INITRAMFS_DIR)/init
	chmod +x $(INITRAMFS_DIR)/sbin/init