VERSION="4.19.57"
SRCDIR="linux-$VERSION"
TARBALL="linux-$VERSION.tar.xz"
URL="https://www.kernel.org/pub/linux/kernel/v4.x"
SHA256SUM="327c5759d5888361d6c9d6adb0c8ad7e3c624eb05bb9e5869d9f3078dd0d3f87"
DEPENDS="initrd"
SUBPKG="linux linux-modules"

get_linux_cpu() {
	case "$TARGET" in
	i*86-*)
		echo "x86"
		;;
	x86_64-*)
		echo "x86_64"
		;;
	arm-*)
		echo "arm"
		;;
	*)
		echo "don't know how to map $TARGET to Linux arch" >&2
		exit 1
		;;
	esac
}

prepare() {
	return
}

build() {
	local INITRDDIR="$PKGDEPLOYDIR/initrd"
	local INITRDLIST="$INITRDDIR/initrd.list"
	local LINUX_CPU=$(get_linux_cpu)

	pkg install -omLD -r "$INITRDDIR" initrd
	pkg install -r "$INITRDDIR" -l initrd initrd > "$INITRDLIST"

	export KBUILD_OUTPUT="$PKGBUILDDIR"

	make -C "$1" O="$PKGBUILDDIR" ARCH="$LINUX_CPU" CROSS_COMPILE="${TARGET}-" mrproper
	cat_file_override "linux.config" > "$PKGBUILDDIR/.config"
	sed -i "$PKGBUILDDIR/.config" -e 's,^CONFIG_CROSS_COMPILE=.*,CONFIG_CROSS_COMPILE="'$TARGET'-",'
	sed -i "$PKGBUILDDIR/.config" -e 's,^CONFIG_INITRAMFS_SOURCE=.*,CONFIG_INITRAMFS_SOURCE="'$INITRDLIST'",'
	sed -i "$PKGBUILDDIR/.config" -e 's,^CONFIG_LOCALVERSION=.*,CONFIG_LOCALVERSION="-'${OS_NAME}-${OS_RELEASE}'",'
	make -C "$1" O="$PKGBUILDDIR" ARCH="$LINUX_CPU" CROSS_COMPILE="${TARGET}-" oldconfig
	make -C "$1" O="$PKGBUILDDIR" ARCH="$LINUX_CPU" CROSS_COMPILE="${TARGET}-" -j $NUMJOBS $LINUX_TGT

	rm -rf "$INITRDDIR"
}

deploy() {
	local SOURCE="$1"
	local LINUX_CPU=$(get_linux_cpu)
	local target

	mkdir -p "$PKGDEPLOYDIR/boot" "$PKGDEPLOYDIR/lib/modules"
	touch "$PKGDEPLOYDIR/linux.desc" "$PKGDEPLOYDIR/linux.files"
	touch "$PKGDEPLOYDIR/linux-modules.desc"
	touch "$PKGDEPLOYDIR/linux-modules.files"

	for target in $LINUX_TGT; do
		case $target in
		*Image)
			cp "arch/$LINUX_CPU/boot/$target" "$PKGDEPLOYDIR/vmlinuz"
			echo "file vmlinuz 0755 0 0" > "$PKGDEPLOYDIR/linux.files"
			;;
		modules)
			export KBUILD_OUTPUT="$PKGBUILDDIR"
			make -C "$SOURCE" O="$PKGBUILDDIR" ARCH="$LINUX_CPU" CROSS_COMPILE="${TARGET}-" INSTALL_MOD_PATH="$PKGDEPLOYDIR" modules_install

			echo "dir lib 0755 0 0" > "$PKGDEPLOYDIR/linux-modules.files"

			pkg_scan_dir "$PKGDEPLOYDIR/lib" | \
				sed "s#$PKGDEPLOYDIR/##g" \
				    >> "$PKGDEPLOYDIR/linux-modules.files"
			;;
		esac
	done
}

check_update() {
	curl --silent -L https://www.kernel.org/feeds/kdist.xml | \
	     grep -o "[0-9.]*: longterm" | grep -o "[0-9.]*" | \
	     verson_find_greatest "$VERSION"
}