# syntax=docker/dockerfile:1.3-labs

ARG BUILD_IMAGE

FROM ${BUILD_IMAGE} AS kernel-build
ARG KERNEL_VERSIONS
ARG TARGETARCH

RUN apk add \
    argp-standalone \
    bison \
    build-base \
    curl \
    diffutils \
    flex \
    gmp-dev \
    libarchive-tools \
    mpc1-dev \
    mpfr-dev \
    ncurses-dev \
    patch \
    xz

COPY / /

# Unpack kernels (download if not present)
RUN <<EOF
set -e
for VERSION in ${KERNEL_VERSIONS}; do
        MAJOR=$(echo ${VERSION} | cut -d . -f 1)
        MAJOR=v${MAJOR}.x
        echo "Downloading/Unpacking $VERSION"
        KERNEL_SOURCE=https://www.kernel.org/pub/linux/kernel/${MAJOR}/linux-${VERSION}.tar.xz
        if [ ! -f sources/linux-${VERSION}.tar.xz ] ; then
		curl -fSLo sources/linux-${VERSION}.tar.xz --create-dirs ${KERNEL_SOURCE}
	fi
        bsdtar xf sources/linux-${VERSION}.tar.xz
done
EOF

# Apply patches to all kernels and move config files into place
RUN <<EOF
set -e
for VERSION in ${KERNEL_VERSIONS}; do
	SERIES=${VERSION%.*}.x
	echo "Patching $VERSION $SERIES"
	cd /linux-${VERSION}
	if [ -d /patches-${SERIES} ]; then
		for patch in /patches-${SERIES}/*.patch; do
			echo "Applying $patch"
			patch -t -F0 -N -u -p1 < "$patch"
		done
	fi
	if [ ${TARGETARCH} = "amd64" ] ; then
		 cp /config-${SERIES}-x86_64 .config
		ARCH=x86 make oldconfig
		ls
	elif [ ${TARGETARCH} = "arm64" ] ; then
		cp /config-${SERIES}-aarch64 .config
		ARCH=arm64 make oldconfig
    elif [ ${TARGETARCH} = "riscv64" ] ; then
		cp /config-${SERIES}-riscv64 .config
		ARCH=riscv64 make oldconfig
	fi
done
EOF

ENTRYPOINT ["/bin/sh"]

FROM scratch
ARG KERNEL_VERSIONS
ARG TARGETARCH
WORKDIR /
COPY --from=kernel-build /linux-${KERNEL_VERSIONS}/.config config-${KERNEL_VERSIONS}-$TARGETARCH