# Alpine-based Zero-OS Initramfs Builder
FROM alpine:3.22

# Set build arguments
ARG TARGETARCH=amd64
ARG BUILDMODE=debug
ARG MINIMAL_MODE=false
ARG USER_UID=1000
ARG USER_GID=1000
ARG USERNAME=builder

# Set environment variables
ENV BUILDMODE=${BUILDMODE}
ENV TARGETARCH=${TARGETARCH}
ENV MINIMAL_MODE=${MINIMAL_MODE}
ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

# Install build dependencies
RUN apk add --no-cache \
    # Build tools
    build-base \
    linux-headers \
    cmake \
    git \
    wget \
    curl \
    cpio \
    xz \
    gzip \
    bc \
    perl \
    python3 \
    upx \
    # Kernel build dependencies
    linux-lts-dev \
    linux-lts \
    elfutils-dev \
    openssl-dev \
    openssl-libs-static \
    pkgconfig \
    flex \
    bison \
    # Archive tools
    tar \
    bzip2 \
    unzip \
    # Text processing
    sed \
    grep \
    findutils \
    # JSON processing for GitHub API
    jq \
    # Rustup for proper Rust musl builds
    rustup

# Setup Rust toolchain for musl builds
RUN rustup-init -y --default-toolchain stable && \
    . ~/.cargo/env && \
    rustup target add x86_64-unknown-linux-musl

# Create directories
RUN mkdir -p /build/initramfs /build/kernel /build/output /build/github /build/configs/zinit /mnt/zinit

# Set working directory
WORKDIR /build

# Copy build scripts and configs
COPY scripts/ /build/scripts/
COPY configs/ /build/configs/

# Make scripts executable
RUN chmod +x /build/scripts/*.sh

# Create build configuration
RUN echo "BUILDMODE=${BUILDMODE}" > /build/build.conf && \
    echo "TARGETARCH=${TARGETARCH}" >> /build/build.conf && \
    echo "MINIMAL_MODE=${MINIMAL_MODE}" >> /build/build.conf && \
    echo "INITRAMFS_ROOT=/build/initramfs" >> /build/build.conf && \
    echo "KERNEL_DIR=/build/kernel" >> /build/build.conf && \
    echo "OUTPUT_DIR=/build/output" >> /build/build.conf && \
    echo "CONFIG_DIR=/build/configs" >> /build/build.conf

# Create user with proper mapping
RUN addgroup -g ${USER_GID} ${USERNAME} && \
    adduser -u ${USER_UID} -G ${USERNAME} -D -s /bin/sh ${USERNAME} && \
    mkdir -p /home/${USERNAME}/.cargo && \
    chown -R ${USERNAME}:${USERNAME} /home/${USERNAME}

# Switch to the mapped user
USER ${USERNAME}

# Set up Rust environment for the user
RUN rustup-init -y --default-toolchain stable && \
    . ~/.cargo/env && \
    rustup target add x86_64-unknown-linux-musl

# Set working directory and ensure permissions
WORKDIR /build
USER root
RUN chown -R ${USERNAME}:${USERNAME} /build
USER ${USERNAME}

# Default command
CMD ["/build/scripts/build-initramfs.sh"]