ifneq ($(PLATFORM),)
	PLATFORM := $(error Setting PLATFORM in make arguments is deprecated, please remove it)
else
	ifneq ($(BOARD),)
		FULL_PATH := $(shell find br-ext-chip-* -name "$(BOARD)*_defconfig")
		ifeq ($(FULL_PATH),)
			FULL_PATH := $(error Cannot find anything for $(BOARD))
		else ifneq ($(shell echo $(FULL_PATH) | wc -w), 1)
			FULL_PATH := $(error For provided '$(BOARD)' multiple options found: $(FULL_PATH))
		endif

		PLATFORM := $(shell echo $(FULL_PATH) | cut -d '/' -f 1 | cut -d '-' -f 4 )

		FAMILY := $(shell grep "/board/" $(FULL_PATH) | head -1 | cut -d "/" -f 3)
		ifeq ($(FAMILY),hi3516cv500)
			BR_VER ?= 2022.08
		else ifeq ($(FAMILY),infinity6e)
			BR_VER ?= 2023.02
		endif
	endif
endif

ROOT_DIR      := $(CURDIR)
BR_EXT_DIR    := $(ROOT_DIR)/br-ext-chip-$(PLATFORM)
SCRIPTS_DIR   := $(ROOT_DIR)/scripts

BR_VER        ?= 2021.02.12
BR_DIR        := $(ROOT_DIR)/buildroot-$(BR_VER)

.PHONY: usage help clean distclean prepare install-deps all toolchain-params run-tests overlayed-rootfs-%

usage help:
	@printf "\n \
	BR-OpenIPC usage:\n \
	  - make help | usage - print this help\n \
	  - make install-deps - install system deps\n \
	  - make prepare - download and unpack buildroot\n \
	  - make list-configs - show available hardware configs list\n \
	  - make BOARD=<BOARD-ID> board-info - show information about\n \
	  	  selected board\n \
	  - make BOARD=<BOARD-ID> all - build all needed for a board\n \
	  	  (toolchain, kernel and rootfs images)\n \
	  - make clean - cleaning before reassembly\n \
	  - make distclean - switching to the factory state\n \
	  - make overlayed-rootfs-<FS-TYPE> ROOTFS_OVERLAYS=... - create rootfs\n \
	  	  image that contains original Buildroot target dir overlayed\n \
	  	  by some custom layers\n\n \
	  Example:\n \
	    make overlayed-rootfs-squashfs ROOTFS_OVERLAYS=./examples/echo_server/overlay\n\n"

distclean:
	@rm -rf output buildroot-$(BR_VER)

clean:
	@rm -rf output/target output/.config

prepare: $(BR_DIR)
$(ROOT_DIR)/buildroot-$(BR_VER).tar.gz:
	wget -O $@ -nv \
		--retry-connrefused --continue --timeout=3 \
		http://buildroot.org/downloads/buildroot-$(BR_VER).tar.gz || \
	wget -O $@ -nv \
		--retry-connrefused --continue --timeout=3 \
		https://github.com/buildroot/buildroot/archive/refs/tags/$(BR_VER).tar.gz

$(BR_DIR): $(ROOT_DIR)/buildroot-$(BR_VER).tar.gz
	tar -C $(ROOT_DIR) -xf buildroot-$(BR_VER).tar.gz
	rm -f buildroot-$(BR_VER).tar.gz


install-deps:
ifneq ($(shell id -u), 0)
	@echo "You must be root to perform this action."
else
	DEBIAN_FRONTEND=noninteractive apt-get update && \
		apt-get -y install \
		build-essential git make libncurses-dev wget curl \
		cpio rsync bc unzip file
endif


%_info:
	@echo
	@cat $(BR_EXT_DIR)/board/$(subst _info,,$@)/config | grep RAM_LINUX_SIZE
	$(eval VENDOR 	:= $(shell echo $@ | cut -d "_" -f 1))
	$(eval FAMILY 	:= $(shell cat $(BR_EXT_DIR)/board/$(subst _info,,$@)/config | grep FAMILY | cut -d "=" -f 2))
	$(eval CHIP	:= $(shell echo $@ | cut -d "_" -f 3))
	@cat $(BR_EXT_DIR)/board/$(FAMILY)/$(CHIP).config

buildroot-version:
	@echo $(BR_VER)

has-nand:
	@sed -rn "s/^BR2_TARGET_ROOTFS_UBI=(y)/\1/p" $(FULL_PATH)

toolname:
	@$(SCRIPTS_DIR)/show_toolchains.sh $(FULL_PATH) $(BR_VER)

list-configs:
ifndef BOARD
	$(error Variable BOARD must be defined to list configs)
else
	@echo
	@ls -1 $(BR_EXT_DIR)/configs
	@echo
endif


# -------------------------------------------------------------------------------------------------
OUT_DIR ?= $(ROOT_DIR)/output

# Buildroot considers relative paths relatively to its' own root directory. So we use absolute paths
# to avoid ambiguity
override OUT_DIR := $(abspath $(OUT_DIR))
BOARD_MAKE := $(MAKE) -C $(BR_DIR) BR2_EXTERNAL=$(BR_EXT_DIR) O=$(OUT_DIR)

define CREATE_TOOLCHAIN_PARAMS
    eval $$($(BOARD_MAKE) -s --no-print-directory VARS=GNU_TARGET_NAME printvars) \
    && $(SCRIPTS_DIR)/create_toolchain_binding.sh $(OUT_DIR)/host/bin $$GNU_TARGET_NAME \
    > $(OUT_DIR)/toolchain-params.mk
endef

# -------------------------------------------------------------------------------------------------
$(OUT_DIR)/.config:
ifndef BOARD
	$(error Variable BOARD must be defined to initialize output directory)
else
	$(BOARD_MAKE) BR2_DEFCONFIG=$(BR_EXT_DIR)/configs/$(BOARD)_defconfig defconfig
endif


$(OUT_DIR)/toolchain-params.mk: $(OUT_DIR)/.config $(SCRIPTS_DIR)/create_toolchain_binding.sh
	$(CREATE_TOOLCHAIN_PARAMS)


# TODO: Elaborate how to compile wireguard-linux-compat under GCC 12 without this patch
define remove-patches
	$(if $(filter $(BR_VER),2020.02.12 2021.02.12),-rm general/package/all-patches/wireguard-linux-compat/remove_fallthrough.patch)
endef


# -------------------------------------------------------------------------------------------------
# build all needed for a board
all: $(OUT_DIR)/.config $(OUT_DIR)/toolchain-params.mk
	$(remove-patches)
	$(BOARD_MAKE) all


# -------------------------------------------------------------------------------------------------
# re-create params file
toolchain-params:
	$(CREATE_TOOLCHAIN_PARAMS)

# -------------------------------------------------------------------------------------------------
# create rootfs image that contains original Buildroot target dir overlayed by some custom layers
# space-separated list of overlays

ROOTFS_OVERLAYS ?=
# overlayed rootfs directory
ROOTFS_OVERLAYED_DIR ?= $(OUT_DIR)/target-overlayed
# overlayed rootfs image's name (without prefix)
ROOTFS_OVERLAYED_IMAGE ?= rootfs-overlayed

overlayed-rootfs-%: $(OUT_DIR)/.config
	$(SCRIPTS_DIR)/create_overlayed_rootfs.sh $(ROOTFS_OVERLAYED_DIR) $(OUT_DIR)/target $(ROOTFS_OVERLAYS)
	$(BOARD_MAKE) $(subst overlayed-,,$@) \
	    BASE_TARGET_DIR=$(abspath $(ROOTFS_OVERLAYED_DIR)) \
	    ROOTFS_$(call UPPERCASE,$(subst overlayed-rootfs-,,$@))_FINAL_IMAGE_NAME=$(ROOTFS_OVERLAYED_IMAGE).$(subst overlayed-rootfs-,,$@)


# -------------------------------------------------------------------------------------------------
board-info:
	@cat $(BR_EXT_DIR)/board/$(BOARD)/config | grep RAM_LINUX_SIZE
	$(eval VENDOR := $(shell echo $(BOARD) | cut -d "_" -f 1))
	$(eval FAMILY := $(shell cat $(BR_EXT_DIR)/board/$(BOARD)/config | grep FAMILY | cut -d "=" -f 2))
	$(eval CHIP   := $(shell echo $(BOARD) | cut -d "_" -f 3))
	@cat $(BR_EXT_DIR)/board/$(FAMILY)/$(CHIP).config
	@cat $(BR_EXT_DIR)/board/$(BOARD)/config

# -------------------------------------------------------------------------------------------------
# such targets (with trimmed `br-` prefix) are passed to Buildroot's Makefile
br-%: $(OUT_DIR)/.config
	$(remove-patches)
	$(BOARD_MAKE) $(subst br-,,$@)


# -------------------------------------------------------------------------------------------------
run-tests:
	$(MAKE) -C $(ROOT_DIR)/tests


# -------------------------------------------------------------------------------------------------
# there are some extra targets of specific packages
include $(sort $(wildcard $(ROOT_DIR)/extra/*.mk))


# -------------------------------------------------------------------------------------------------
# util stuff is below
UPPERCASE = $(shell echo $(1) | tr a-z A-Z)