of() {
    if [[ $# -eq 1 && "$1" == "status" ]]; then
        if [[ -n "$WM_PROJECT_DIR" ]]; then
            echo "✅ OpenFOAM is active"
            echo "📂 WM_PROJECT_DIR: $WM_PROJECT_DIR"
            echo "📂 WM_PROJECT_USER_DIR: $WM_PROJECT_USER_DIR"
            echo "🔢 Version: ${WM_PROJECT_VERSION:-unknown}"
        else
            echo "ℹ️ No OpenFOAM environment is currently active"
        fi
        return 0
    fi

    if [[ $# -lt 1 || $# -gt 2 ]]; then
        cat <<EOF
Usage: of <com|org> [version]
       of status        # Show current OpenFOAM environment

Examples:
  of com 2506    # Activate OpenFOAM.com v2506
  of org 13      # Activate OpenFOAM.org v13
  of com         # Picks up latest OpenFOAM.com
  of org         # Picks latest numeric OpenFOAM.org
EOF
        return 1
    fi

    if [[ -n "$WM_PROJECT_DIR" ]]; then
        echo "ℹ️ OpenFOAM already sourced: $WM_PROJECT_DIR"
        return 0
    fi

    local branch="$1" version="$2" OFpath

    find_latest_version() {
        local dir="$1" prefix="$2"
        [[ ! -d "$dir" ]] && return 1
        ls -1 "$dir" 2>/dev/null | grep -E "^${prefix}[0-9]+" | grep -oE '[0-9]+' | sort -n | tail -n1
    }

    case "$branch" in
        com)
            if [[ -n "$version" ]]; then
                OFpath="/usr/lib/openfoam/openfoam${version}/etc/bashrc"
            else
                version="$(find_latest_version /usr/lib/openfoam openfoam)"
                [[ -z "$version" ]] && { echo "❌ No OpenFOAM.com found in /usr/lib/openfoam" >&2; return 1; }
                OFpath="/usr/lib/openfoam/openfoam${version}/etc/bashrc"
            fi
            ;;
        org)
            if [[ -n "$version" ]]; then
                OFpath="/opt/openfoam${version}/etc/bashrc"
                [[ ! -f "$OFpath" ]] && OFpath="/opt/${version}/etc/bashrc"
            else
                version="$(find_latest_version /opt openfoam)"
                [[ -z "$version" ]] && { echo "❌ No OpenFOAM.org found in /opt" >&2; return 1; }
                OFpath="/opt/openfoam${version}/etc/bashrc"
            fi
            ;;
        *)
            echo "❌ Invalid option: '$branch' (use 'com' or 'org')" >&2
            return 1
            ;;
    esac

    [[ ! -f "$OFpath" ]] && { echo "❌ bashrc not found at $OFpath" >&2; return 1; }

    # WSL-aware WM_PROJECT_USER_DIR
    if [[ -d /mnt/c ]]; then
        win_user="$(/mnt/c/Windows/System32/cmd.exe /c 'echo %USERNAME%' | tr -d '\r')"
        export WM_PROJECT_USER_DIR="/mnt/c/Users/${win_user}/openfoam-data/${USER}-${version}"
    else
        export WM_PROJECT_USER_DIR="${HOME}/openfoam-data/${USER}-${version}"
    fi

    if source "$OFpath" WM_PROJECT_USER_DIR="$WM_PROJECT_USER_DIR"; then
        echo "✅ Activated OpenFOAM ($branch $version)"
        echo "📂 WM_PROJECT_USER_DIR=\"$WM_PROJECT_USER_DIR\""
    else
        echo "❌ Failed to source $OFpath" >&2
        return 1
    fi
}