#!/bin/bash
#
# ================================================================
#  OpenMC + Python Runner (Apptainer-based)
# ================================================================
#  Description:
#    This script runs either:
#      (1) OpenMC directly inside an Apptainer container, or
#      (2) a Python script using the same container environment.
#
#  Usage:
#    ./run_openmc.sh                → Run OpenMC in the container
#    ./run_openmc.sh script.py args → Run Python script with args
#    ./run_openmc.sh -h | --help    → Show help
#
#  Behavior:
#    - The current working directory is mounted into /workspace inside the container.
#    - The OpenMC library directory is mounted into /libs.
#    - The output log is saved in the same directory as the run:
#         * openmc_run.log  for OpenMC runs
#         * <scriptname>.log for Python runs
#
#  Example:
#    ./run_openmc.sh               # Run OpenMC normally
#    ./run_openmc.sh input.py      # API can be called inside the script
#
# ================================================================

# === Config ===
# ================================================================
# NOTE: Update SIF and LIB_DIR paths as needed !!!!!!!!!!!!!!!!!!!
# ================================================================
SIF="/afs/psi.ch/project/stars/workspace/RND/SB-RND-ACT-004-25/SC41/openmc/openmc_apptainer/openmc.sif"
LIB_DIR="/afs/psi.ch/project/stars/workspace/RND/SB-RND-ACT-004-25/SC41/openmc/lib_mine"
HOST_DIR="$(pwd)"
CONTAINER_DIR="/workspace"

# === Help ===
show_help() {
cat << EOF
Usage: $(basename "$0") [script.py [args...]]

Run OpenMC or a Python script inside an Apptainer container.

Options:
  -h, --help      Show this help message and exit

Modes:
  • No arguments        → Runs OpenMC inside the container
  • script.py [args...] → Runs the given Python script using py

Examples:
  $(basename "$0")                  # Run OpenMC normally
  $(basename "$0") run_case.py      # Run Python script

Environment:
  Container: ${SIF}
  Host dir : ${HOST_DIR}
  Lib dir  : ${LIB_DIR}
EOF
}

# === Handle Help Flag ===
if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    show_help
    exit 0
fi

# === Mode ===
if [ -z "$1" ]; then
    MODE="openmc"
else
    MODE="python"
    PYTHON_SCRIPT="$1"
    shift
fi

# === Log File ===
if [ "$MODE" = "openmc" ]; then
    LOG_FILE="${HOST_DIR}/openmc_run.log"
else
    if [ ! -f "${HOST_DIR}/${PYTHON_SCRIPT}" ]; then
        echo "Error: Python script '${PYTHON_SCRIPT}' not found in ${HOST_DIR}."
        exit 1
    fi
    LOG_FILE="${HOST_DIR}/${PYTHON_SCRIPT%.*}.log"
fi

echo "---------------------------------------------------------------"
echo " Running in container: ${SIF}"
echo " Host directory      : ${HOST_DIR}"
echo " Container directory : ${CONTAINER_DIR}"
echo " Library mount       : ${LIB_DIR} -> /libs"
echo " Log file            : ${LOG_FILE}"
echo "---------------------------------------------------------------"

# === Exec===
if [ "$MODE" = "openmc" ]; then
    echo ">>> Starting OpenMC run..."
    apptainer exec \
        --bind "${HOST_DIR}:${CONTAINER_DIR}" \
        --bind "${LIB_DIR}:/libs" \
        --pwd "${CONTAINER_DIR}" "${SIF}" \
        openmc | tee "${LOG_FILE}"
else
    echo ">>> Running Python script: ${PYTHON_SCRIPT}"
    apptainer exec \
        --bind "${HOST_DIR}:${CONTAINER_DIR}" \
        --bind "${LIB_DIR}:/libs" \
        --pwd "${CONTAINER_DIR}" "${SIF}" \
        python3.11 "${CONTAINER_DIR}/${PYTHON_SCRIPT}" "$@" | tee "${LOG_FILE}"
fi