configure

#!/bin/sh
# Configure script for coexpr package
# Detects OpenMP support and configures Makevars accordingly

# Get R configuration
: ${R_HOME=`R RHOME`}
if test -z "${R_HOME}"; then
  echo "Could not determine R_HOME"
  exit 1
fi

CC=`"${R_HOME}/bin/R" CMD config CC`
CFLAGS=`"${R_HOME}/bin/R" CMD config CFLAGS`
CXX=`"${R_HOME}/bin/R" CMD config CXX`
CXXFLAGS=`"${R_HOME}/bin/R" CMD config CXXFLAGS`
SHLIB_OPENMP_CXXFLAGS=`"${R_HOME}/bin/R" CMD config SHLIB_OPENMP_CXXFLAGS`

# Check for OpenMP support
OPENMP_CXXFLAGS=""
OPENMP_LIBS=""
EXTRA_CXXFLAGS=""

echo "Checking for OpenMP support..."

# macOS with Homebrew libomp
if [ "$(uname -s)" = "Darwin" ]; then
  LIBOMP_PATH="/opt/homebrew/opt/libomp"
  if [ -f "${LIBOMP_PATH}/lib/libomp.dylib" ]; then
    echo "  Found Homebrew libomp at ${LIBOMP_PATH}"
    OPENMP_CXXFLAGS="-fopenmp -I${LIBOMP_PATH}/include"
    # Use explicit path to override R's bundled libomp
    OPENMP_LIBS="-L${LIBOMP_PATH}/lib -Wl,-rpath,${LIBOMP_PATH}/lib ${LIBOMP_PATH}/lib/libomp.dylib"
  elif [ -n "${SHLIB_OPENMP_CXXFLAGS}" ]; then
    echo "  Using R's OpenMP flags: ${SHLIB_OPENMP_CXXFLAGS}"
    OPENMP_CXXFLAGS="${SHLIB_OPENMP_CXXFLAGS}"
    OPENMP_LIBS="${SHLIB_OPENMP_CXXFLAGS}"
  else
    echo "  OpenMP not found, building without parallel support"
  fi
else
  # Linux and other systems
  if [ -n "${SHLIB_OPENMP_CXXFLAGS}" ]; then
    echo "  Using R's OpenMP flags: ${SHLIB_OPENMP_CXXFLAGS}"
    OPENMP_CXXFLAGS="${SHLIB_OPENMP_CXXFLAGS}"
    OPENMP_LIBS="${SHLIB_OPENMP_CXXFLAGS}"
  else
    echo "  OpenMP not found, building without parallel support"
  fi
fi

# Write Makevars
echo "Creating src/Makevars..."
sed -e "s|@OPENMP_CXXFLAGS@|${OPENMP_CXXFLAGS}|g" \
    -e "s|@OPENMP_LIBS@|${OPENMP_LIBS}|g" \
    -e "s|@EXTRA_CXXFLAGS@|${EXTRA_CXXFLAGS}|g" \
    src/Makevars.in > src/Makevars

echo "Configuration complete."