#!/bin/bash
#------------------------------------------------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     | Website:  https://openfoam.org
#   \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
#    \\/     M anipulation  |
#------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM.
#
#     OpenFOAM 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.
#
#     OpenFOAM 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
#     foamExec
#
# Description
#     Usage: foamExec <foamCommand> ...
#
#     Runs the executable <foamCommand> with any subsequent options. This does
#     not require the OpenFOAM bashrc file to have been sourced. This script
#     will source the bashrc file and initialise the OpenFOAM environment
#     temporarily for the duration of command's execution. For example:
#
#     \code
#         ~/OpenFOAM/OpenFOAM-12/bin/foamExec blockMesh
#         ~/OpenFOAM/OpenFOAM-12/bin/foamExec decomposePar
#         ~/OpenFOAM/OpenFOAM-12/bin/foamExec mpirun -n 4 foamRun -parallel
#         ~/OpenFOAM/OpenFOAM-12/bin/foamExec reconstructPar
#     \endcode
#
#     Or, perhaps equivalently:
#
#     \code
#        ~/OpenFOAM/OpenFOAM-12/bin/foamExec ./Allrun
#     \endcode
#
#     Note that commands including environment variables must have the '$'
#     character escaped with '\' so that the variables do not get expanded to
#     nothing in the outer/interactive shell. For example, to copy a tutorial:
#
#     \code
#         ~/OpenFOAM/OpenFOAM-12/bin/foamExec ls \$FOAM_TUTORIALS/*
#         ~/OpenFOAM/OpenFOAM-12/bin/foamExec \
#             cp -r \$FOAM_TUTORIALS/incompressibleFluid/pitzDaily .
#     \endcode
#
# Note
#     This script must exist in $FOAM_INST_DIR/OpenFOAM-<VERSION>/bin/
#     or $FOAM_INST_DIR/openfoam<VERSION>/bin/ (for deb packages), and the
#     foamEtcFile script must also be in the same directory
#
#     Expansion of environment variables requires envsubst to be available on
#     the system
#
# See also
#    foamEtcFile
#
#------------------------------------------------------------------------------
usage() {
    cat<<USAGE

Usage: ${0##*/} [OPTION] <application> ...

options:
  -prefix <dir>     specify an alternative installation prefix
                    pass through to foamEtcFile and set as FOAM_INST_DIR
  -version <ver>    specify an alternative OpenFOAM version
                    pass through to foamEtcFile
  -help             print the usage

Runs an OpenFOAM <application> without the OpenFOAM environment having been
initialised. The environment is set up on the fly. Can be used as a single
executable via which any part of OpenFOAM can be run. Useful for working with
packaging processes that require a single executable per package, and also if
frequently changing versions on the same system.

USAGE
}

error() {
    exec 1>&2
    while [ "$#" -ge 1 ]; do echo "$1"; shift; done
    usage
    exit 1
}

#-------------------------------------------------------------------------------

# The bin dir
binDir="${0%/*}"

# The project dir
projectDir="${binDir%/bin}"

# The prefix dir (same as $FOAM_INST_DIR by default)
prefixDir="${projectDir%/*}"

# Parse options
foamEtcFileOpts=()
unset version
while [ "$#" -gt 0 ]
do
    case "$1" in
    -h | -help)
        usage && exit 0
        ;;
    -m | -mode)
        [ "$#" -ge 2 ] || error "'$1' option requires an argument"
        foamEtcFileOpts+=("$1" "$2") # pass through to foamEtcFile
        shift
        ;;
    -p | -prefix)
        [ "$#" -ge 2 ] || error "'$1' option requires an argument"
        foamEtcFileOpts+=("$1" "$2") # pass through to foamEtcFile
        prefixDir="$2"
        shift
        ;;
    -v | -version)
        [ "$#" -ge 2 ] || error "'$1' option requires an argument"
        foamEtcFileOpts+=("$1" "$2") # pass through to foamEtcFile
        version="$2"
        shift
        ;;
    --)
        shift
        break
        ;;
    -*)
        error "invalid option '$1'"
        ;;
    *)
        break
        ;;
    esac
    shift
done

# Check that something is being executed
[ "$#" -ge 1 ] || error "no application specified"

# Source the OpenFOAM bashrc. Done in a function to prevent errors being
# generated within the sourced scripts. Not sure exactly why.
sourceBashrc()
{
    # Locate the bashrc file
    bashrcFile="$("$binDir"/foamEtcFile "${foamEtcFileOpts[@]}" bashrc)" || \
        error echo "bashrc file could not be found for \
    OpenFOAM-${version:-${WM_PROJECT_VERSION:-???}}"

    # Source the bashrc file
    FOAM_INST_DIR="$prefixDir" . "$bashrcFile"
}
sourceBashrc

# Expand any variables in the command arguments (if possible)
if command -v envsubst &> /dev/null
then
    cmd=()
    while [ "$#" -gt 0 ]
    do
        cmd+=("$(printf -- "%s" "$1" | envsubst)")
        shift 1
    done
else
    cmd=("$@")
fi

# Execute the command
exec "${cmd[@]}"

#------------------------------------------------------------------------------