ARG BUILD_BASE_TAG=dev
ARG DOCKER_IMAGE_ROOT=monok8s

FROM --platform=$BUILDPLATFORM ${DOCKER_IMAGE_ROOT}/build-base:${BUILD_BASE_TAG} AS build

# Install glibc cross-compiler for kernel and standard build dependencies
RUN apt-get update && apt-get install -y \
    crossbuild-essential-arm64 \
    patch bzip2 pkg-config \
    libxml2-dev libtclap-dev

# Provision the musl cross-compiler from musl.cc
RUN curl -O https://musl.cc/aarch64-linux-musl-cross.tgz && \
    tar xzf aarch64-linux-musl-cross.tgz -C /opt && \
    rm aarch64-linux-musl-cross.tgz

# Expose the musl compiler to the PATH
ENV PATH="/opt/aarch64-linux-musl-cross/bin:${PATH}"

WORKDIR /src

ARG NXP_TAR
ARG MONO_ASK_TAR
ARG LIBNFNETLINK_TAR
ARG LIBNFCT_TAR

ARG NXP_VERSION
ARG MONO_ASK_VERSION
ARG LIBNFNETLINK_VERSION
ARG LIBNFCT_VERSION

# Linux kernel
COPY "${NXP_TAR}" ./kernel.tar.gz

# Copy the ASK and Netfilter tarballs 
COPY "${MONO_ASK_TAR}" .
COPY "${LIBNFNETLINK_TAR}" ./libnfnetlink-${LIBNFNETLINK_VERSION}.tar.bz2
COPY "${LIBNFCT_TAR}" ./libnetfilter_conntrack-${LIBNFCT_VERSION}.tar.xz

# Extract ASK and place Netfilter dependencies where the Makefile expects them
RUN mkdir -p ASK/sources/tarballs && \
    tar zxf "${MONO_ASK_VERSION}.tar.gz" -C "ASK" --strip-components=1 && \
    mv libnfnetlink-${LIBNFNETLINK_VERSION}.tar.bz2 ASK/sources/tarballs/ && \
    mv libnetfilter_conntrack-${LIBNFCT_VERSION}.tar.xz ASK/sources/tarballs/

RUN mkdir linux && tar zxf "kernel.tar.gz" -C "linux" --strip-components=1

WORKDIR /src/ASK

# 1. Build Kernel and Modules with the glibc cross-compiler
RUN make kernel KDIR=/src/linux CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64
RUN make modules KDIR=/src/linux CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64

# 2. Build Userspace with the musl cross-compiler
# Overriding HOST forces the Netfilter./configure steps to use musl
# Setting CC and CXX with -static ensures portability in the Alpine rootfs
RUN make sources KDIR=/src/linux CROSS_COMPILE=aarch64-linux-musl- ARCH=arm64 HOST=aarch64-linux-musl
RUN make userspace KDIR=/src/linux CROSS_COMPILE=aarch64-linux-musl- ARCH=arm64 \
    HOST=aarch64-linux-musl \
    CC="aarch64-linux-musl-gcc -static" \
    CXX="aarch64-linux-musl-g++ -static"

# Stage the artifacts
RUN make dist

# Export stage to isolate compiled artifacts for monok8s build-rootfs.sh
FROM scratch AS export
COPY --from=build /src/ASK/dist/ /ASK/
COPY --from=build /src/linux/arch/arm64/boot/Image /kernel/Image