configure

#!/usr/bin/env bash
# Detect build dependencies and configure .cargo/config.toml.
# Run once after cloning or when changing toolchains.
set -e

CARGO_DIR=".cargo"
CONFIG="$CARGO_DIR/config.toml"

echo "Checking build dependencies..."

# Check for C/C++ compiler
if ! command -v cc &>/dev/null && ! command -v gcc &>/dev/null; then
    echo "ERROR: No C compiler found. Install build-essential:"
    echo "  sudo apt install build-essential"
    exit 1
fi

# Check for Rust
if ! command -v cargo &>/dev/null; then
    echo "ERROR: cargo not found. Install Rust: https://rustup.rs"
    exit 1
fi

# Find GCC include path (needed by bindgen for stddef.h)
GCC_INCLUDE=""
for dir in /usr/lib/gcc/x86_64-linux-gnu/*/include /usr/lib/gcc/aarch64-linux-gnu/*/include; do
    if [ -f "$dir/stddef.h" ]; then
        GCC_INCLUDE="$dir"
        break
    fi
done

# Check if libclang-common headers are available (makes the workaround unnecessary)
CLANG_HAS_STDDEF=false
for dir in /usr/lib/clang/*/include; do
    if [ -f "$dir/stddef.h" ]; then
        CLANG_HAS_STDDEF=true
        break
    fi
done

mkdir -p "$CARGO_DIR"

if [ "$CLANG_HAS_STDDEF" = true ]; then
    echo "  libclang headers found — no workaround needed"
    cat > "$CONFIG" <<'EOF'
# No special configuration needed — libclang headers are available.
EOF
elif [ -n "$GCC_INCLUDE" ]; then
    echo "  GCC include path: $GCC_INCLUDE"
    cat > "$CONFIG" <<EOF
[env]
# Points bindgen at GCC's stddef.h (auto-detected by ./configure).
# Install libclang-common-*-dev to remove this workaround.
BINDGEN_EXTRA_CLANG_ARGS = "-I${GCC_INCLUDE}"
EOF
else
    echo "WARNING: Could not find stddef.h in GCC or clang paths."
    echo "  RocksDB build may fail. Try: sudo apt install libclang-common-18-dev"
    cat > "$CONFIG" <<'EOF'
# WARNING: stddef.h not found. RocksDB build may fail.
# Install libclang-common-*-dev or set BINDGEN_EXTRA_CLANG_ARGS manually.
EOF
fi

echo "  Rust: $(rustc --version)"
echo "  Cargo config: $CONFIG"
echo ""

# Verify the build works
echo "Running cargo check..."
if cargo check 2>&1 | tail -3; then
    echo ""
    echo "Build OK. Run tests with: cargo test"
else
    echo ""
    echo "Build failed. See errors above."
    exit 1
fi