#!/bin/sh
#------------------------------------------------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | Copyright (C) 2017 OpenFOAM Foundation
#    \\/     M anipulation  |
#-------------------------------------------------------------------------------
# License
#     This program is free software: you can redistribute it and/or modify it
#     under the terms of the GNU General Public License as published by
#     the Free Software Foundation, either version 3 of the License, or
#     (at your option) any later version.
#
#     This program is distributed in the hope that it will be useful, but
#     WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
#     or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
#     for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
#
# Script
#     openfoam4-linux
#
# Description
#     Run script for an OpenFOAM 4 Docker image at:
#     https://hub.docker.com/r/openfoam
#
#------------------------------------------------------------------------------
Script=${0##*/}
VER=4.1

usage () {
    exec 1>&2
    while [ "$#" -ge 1 ]; do echo "$1"; shift; done
    cat <<USAGE

Usage: ${0##*/} [OPTIONS]
options:
  -d | -dir            host directory mounted (defaults to current directory)
  -x | -xhost          use custom X authority and give container host network
  -h | -help           help

Launches the OpenFOAM ${VER} Docker image.
- Requires installation of docker-engine.
- Runs a "containerized" bash shell environment where the user can run OpenFOAM
  and, optionally, ParaView (see below).
- The container mounts the user's file system so that case files are stored
  permanently.  The container mounts the current directory by default, but the
  user can also specify a particular directory using the "-d" option.
- Mounting the user's HOME directory is disallowed.
- The '-xhost' option is useful when accessing the host via 'ssh -X'.
  This option should only be used when strictly necessary, as it relies on the
  option '--net=host' when launching the container in Docker, which will
  give to the container full access to the Docker host network stack and
  potentially the host's system services that rely on network communication,
  making it potentially insecure.

Example:
To store data in ${HOME}/OpenFOAM/${USER}-${VER}, the user can launch
${Script} either by:
    cd ${HOME}/OpenFOAM/${USER}-${VER} && ${Script}
or
    ${Script} -d ${HOME}/OpenFOAM/${USER}-${VER}

Further Information:
http://openfoam.org/download/4-1-linux

Note:
The container user name appears as "openfoam" but it is just an alias.

USAGE
    exit 1
}

DOCKER_IMAGE='openfoam/openfoam4-paraview50'
MOUNT_DIR=$(pwd)
CUSTOM_XAUTH=""
DOCKER_OPTIONS=""

while [ "$#" -gt 0 ]
do
   case "$1" in
   -d | -dir)
      [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
      MOUNT_DIR=$2
      shift 2
      ;;
   -x | -xhost)
      CUSTOM_XAUTH=yes
      shift
      ;;
   -h | -help)
      usage
      ;;
   -*)
      usage "Invalid option '$1'"
      ;;
   *)
      break
      ;;
    esac
done

[ -d "$MOUNT_DIR" ] && \
    MOUNT_DIR=$(cd $MOUNT_DIR && pwd -P) || \
    usage "No directory exists: $MOUNT_DIR"

[ "$MOUNT_DIR" = "$(cd $HOME && pwd -P)" ] && \
    usage "Mount directory cannot be the user's home directory" \
          "Make a subdirectory and run from there, e.g." \
          "    mkdir -p ${HOME}/OpenFOAM/$(whoami)-${VER}" \
          "    ${Script} -d ${HOME}/OpenFOAM/$(whoami)-${VER}"

if [ -n "$CUSTOM_XAUTH" ]
then
    XAUTH_PATH="${MOUNT_DIR}/.docker.xauth.$$"
    touch "${XAUTH_PATH}"

    # Generate a custom X-authority file that allows any hostname
    xauth nlist $DISPLAY |  sed -e 's/^..../ffff/' | \
        xauth -f $XAUTH_PATH nmerge -

    DOCKER_OPTIONS="-e XAUTHORITY=$XAUTH_PATH
                    -v $XAUTH_PATH:$XAUTH_PATH
                    --net=host"
fi


USER_ID=$(id -u 2> /dev/null)
[ -n "$USER_ID" ] && GROUP_ID=$(id -g) || usage "Cannot determine current user ID"

HOME_DIR='/home/openfoam'

echo "Launching $0"
echo "User: \"$(id -un)\" (ID $USER_ID, group ID $GROUP_ID)"

docker run -it \
    --rm \
    -e DISPLAY=$DISPLAY \
    -u $USER_ID:$GROUP_ID \
    -v /tmp/.X11-unix:/tmp/.X11-unix \
    -v $MOUNT_DIR:$HOME_DIR \
    $DOCKER_OPTIONS \
    $DOCKER_IMAGE

[ -n "$CUSTOM_XAUTH" -a -e "${XAUTH_PATH}" ] && rm "${XAUTH_PATH}"
