#!/bin/sh
# build-nvidia-module.sh — install NVIDIA proprietary driver into ISO overlay
#
# Downloads the official NVIDIA .run installer, extracts kernel modules and
# userspace tools (nvidia-smi, libnvidia-ml). Everything is proprietary NVIDIA.
#
# Output is cached in DIST_DIR/nvidia-<version>-<kver>/ so subsequent builds
# are instant unless NVIDIA_DRIVER_VERSION or kernel version changes.
#
# Output layout:
#   $CACHE_DIR/modules/   — nvidia*.ko files
#   $CACHE_DIR/bin/       — nvidia-smi, nvidia-debugdump
#   $CACHE_DIR/lib/       — libnvidia-ml.so*, libcuda.so* (for nvidia-smi)

set -e

NVIDIA_VERSION="$1"
DIST_DIR="$2"

[ -n "$NVIDIA_VERSION" ] || { echo "usage: $0 <nvidia-version> <dist-dir>"; exit 1; }
[ -n "$DIST_DIR" ]       || { echo "usage: $0 <nvidia-version> <dist-dir>"; exit 1; }

# Detect kernel version from installed headers
KVER=$(ls /usr/src/ 2>/dev/null | grep '^linux-headers-' | sed 's/linux-headers-//' | head -1)
if [ -z "$KVER" ]; then
    echo "=== installing linux-lts-dev ==="
    apk add --quiet linux-lts-dev
    KVER=$(ls /usr/src/ | grep '^linux-headers-' | sed 's/linux-headers-//' | head -1)
fi
KDIR="/usr/src/linux-headers-${KVER}"
echo "=== NVIDIA ${NVIDIA_VERSION} (proprietary) for kernel ${KVER} ==="

CACHE_DIR="${DIST_DIR}/nvidia-${NVIDIA_VERSION}-${KVER}"
if [ -d "$CACHE_DIR/modules" ] && [ -f "$CACHE_DIR/bin/nvidia-smi" ]; then
    echo "=== NVIDIA cached, skipping build ==="
    echo "cache: $CACHE_DIR"
    echo "modules: $(ls "$CACHE_DIR/modules/"*.ko 2>/dev/null | wc -l) .ko files"
    exit 0
fi

# Install build dependencies
apk add --quiet gcc make perl linux-lts-dev wget

# Download official NVIDIA .run installer (proprietary)
RUN_FILE="/var/tmp/NVIDIA-Linux-x86_64-${NVIDIA_VERSION}.run"
if [ ! -f "$RUN_FILE" ]; then
    echo "=== downloading NVIDIA ${NVIDIA_VERSION} installer ==="
    wget -q --show-progress \
        -O "$RUN_FILE" \
        "https://download.nvidia.com/XFree86/Linux-x86_64/${NVIDIA_VERSION}/NVIDIA-Linux-x86_64-${NVIDIA_VERSION}.run"
fi

# Extract installer contents
echo "=== extracting installer ==="
chmod +x "$RUN_FILE"
EXTRACT_DIR="/var/tmp/nvidia-extract-${NVIDIA_VERSION}"
rm -rf "$EXTRACT_DIR"
"$RUN_FILE" --extract-only --target "$EXTRACT_DIR"

# Build kernel modules from extracted source
echo "=== building kernel modules ($(nproc) cores) ==="
cd "$EXTRACT_DIR/kernel"
make -j$(nproc) KERNEL_UNAME="$KVER" SYSSRC="$KDIR" modules 2>&1 | tail -5

# Collect outputs
mkdir -p "$CACHE_DIR/modules" "$CACHE_DIR/bin" "$CACHE_DIR/lib"

find "$EXTRACT_DIR/kernel" -name '*.ko' -exec cp {} "$CACHE_DIR/modules/" \;
for ko in "$CACHE_DIR/modules/"*.ko; do
    strip --strip-debug "$ko" 2>/dev/null || true
done

cp "$EXTRACT_DIR/nvidia-smi"         "$CACHE_DIR/bin/"
cp "$EXTRACT_DIR/libnvidia-ml.so."*  "$CACHE_DIR/lib/" 2>/dev/null || true
# libcuda stub needed by nvidia-smi at runtime
cp "$EXTRACT_DIR/libcuda.so."*       "$CACHE_DIR/lib/" 2>/dev/null || true

echo "=== NVIDIA build complete ==="
echo "cache: $CACHE_DIR"
echo "modules: $(ls "$CACHE_DIR/modules/"*.ko | wc -l) .ko files"
ls -lh "$CACHE_DIR/bin/"