#!/usr/bin/env bash
# Build a protobuf C++ toolchain for the native Shard protocol.
#
# The Python side needs nothing beyond `pip install grpcio-tools` — it bundles
# protoc. The C++ side needs libprotobuf headers and a protoc binary, and a
# machine that has neither (no protobuf-devel, no cmake, no system protoc) can
# still get a working one from source with this script. It is the exact recipe
# DGR-002 used to build and run the C++ conformance test.
#
# gRPC C++ is deliberately NOT built here. The conformance test only needs
# message types, so verifying the schema does not require the whole gRPC stack.
# The worker (DGR-008) will need gRPC C++ and should extend this script then.
#
# Usage:
#   scripts/bootstrap_native_toolchain.sh [install-prefix]
#
# Then:
#   cmake -S packages/node/native -B build/native -DCMAKE_PREFIX_PATH=<prefix>
#   cmake --build build/native -j
#   ctest --test-dir build/native --output-on-failure

set -euo pipefail

PREFIX="${1:-${PWD}/build/native-toolchain}"
WORK="$(mktemp -d)"
trap 'rm -rf "${WORK}"' EXIT

# Pinned: the C++ runtime a generated stub is compiled against must be a version
# that stub is allowed to use, so these are exact, not floating.
PROTOBUF_VERSION="33.1"
ABSEIL_VERSION="20250814.1"

command -v cmake >/dev/null || {
  echo "cmake is required (pip install cmake==4.4.0)" >&2
  exit 1
}

echo "--- fetching protobuf ${PROTOBUF_VERSION} and abseil ${ABSEIL_VERSION}"
cd "${WORK}"
curl -sfL -o protobuf.tar.gz \
  "https://github.com/protocolbuffers/protobuf/releases/download/v${PROTOBUF_VERSION}/protobuf-${PROTOBUF_VERSION}.tar.gz"
tar xzf protobuf.tar.gz

# The protobuf release tarball ships utf8_range but not abseil, and its default
# CMake provider expects abseil as a submodule, so vendor it into place.
curl -sfL -o abseil.tar.gz \
  "https://github.com/abseil/abseil-cpp/releases/download/${ABSEIL_VERSION}/abseil-cpp-${ABSEIL_VERSION}.tar.gz"
tar xzf abseil.tar.gz
rm -rf "protobuf-${PROTOBUF_VERSION}/third_party/abseil-cpp"
mv "abseil-cpp-${ABSEIL_VERSION}" "protobuf-${PROTOBUF_VERSION}/third_party/abseil-cpp"

echo "--- building protobuf into ${PREFIX}"
cmake -S "protobuf-${PROTOBUF_VERSION}" -B build \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX="${PREFIX}" \
  -DCMAKE_POSITION_INDEPENDENT_CODE=ON \
  -Dprotobuf_ABSL_PROVIDER=module \
  -Dprotobuf_BUILD_TESTS=OFF \
  -Dprotobuf_BUILD_SHARED_LIBS=OFF \
  -DABSL_PROPAGATE_CXX_STD=ON
cmake --build build -j"$(nproc)"
cmake --install build

echo "--- done"
"${PREFIX}/bin/protoc" --version
echo "configure the protocol build with: -DCMAKE_PREFIX_PATH=${PREFIX}"