#!/bin/sh
cd "${0%/*}" || exit                                # Run from this directory
. ${WM_PROJECT_DIR:?}/bin/tools/RunFunctions        # Tutorial run functions
#------------------------------------------------------------------------------
# Dummy external solver to communicate with OpenFOAM via externalCoupled
# functionObject
#
# Functionality is hard-coded for this particular test case
# - patch temperatures increased by 1K on each step
#
# -----------------------------------------------------------------------------

# Check for unassigned variables
set -u

echo "Executing dummy external solver"

commsDir="comms"
patchDir="heater_topAir/coupleGroup"
fieldName="T"

lockFile="${commsDir}/OpenFOAM.lock"
dataFile="${commsDir}/${patchDir}/${fieldName}"
waitSec=5
timeOut=100
nSteps=1000 # maximum number of time steps. Note: should be more than
            # number of iterations on the OpenFOAM side

stopAt=300  # external solver signals OpenFOAM to stop

refGrad=0
valueFraction=1

# Remove any old junk
rm -f "$lockFile"

log()
{
    echo "External: $@"
}


# Create lock file to pass control to OpenFOAM
useMaster()
{
    log "creating lock file '${lockFile}'"
    echo "status=openfoam" >| ${lockFile}
}

# Lock file with special content to stop OpenFOAM master
stopMasterNow()
{
    log "writeNow terminate via lock file '${lockFile}'"
    echo "action=writeNow" >| ${lockFile}
}


# Patch size (heater/minY)
nFaces1=$(getNumberOfPatchFaces minY heater) || exit $?

# Patch size (topAir/minX)
nFaces2=$(getNumberOfPatchFaces minX topAir) || exit $?


init()
{
    log "init - creating ${dataFile}.in"
    cat /dev/null >| "${dataFile}.in"

    # Local face counter, Local refValue
    local nFaces refValue

    # Patch (heater/minY)
    nFaces="$nFaces1"
    refValue=500

    log "init - adding $nFaces data elements with refValue $refValue"

    while [ "$nFaces" -gt 0 ]
    do
        nFaces=$((nFaces - 1))
        echo "$refValue $refGrad $valueFraction"
    done >> "${dataFile}.in"


    # Patch (topAir/minX)
    nFaces="$nFaces2"
    refValue=300

    log "init - adding $nFaces data elements with refValue $refValue"

    while [ "$nFaces" -gt 0 ]
    do
        nFaces=$((nFaces - 1))
        echo "$refValue $refGrad $valueFraction"
    done >> "${dataFile}.in"

    # Verify line count?
    # log "init ($(wc -l ${dataFile}.in))"

    # Give time for T.in file to flush
    sleep 1

    useMaster
}


# Create the comms directory
mkdir -p ${commsDir}/${patchDir}

# Tutorial case uses 'initByExternal' option, so we must provide initial values
init


totalWait=0
step=0
while [ $step -lt $nSteps ]
do
    if [ -f $lockFile ]
    then
        if grep -q "status=done" ${lockFile}
        then
             log "found lock file '${lockFile}' with 'status=done' - finished"
             break
        elif [ -s $lockFile ]
        then
             log "found lock file '${lockFile}' containing '$(< $lockFile)' - waiting"
        else
             log "found lock file '${lockFile}' - waiting"
        fi

        totalWait=$(expr $totalWait + $waitSec)
        if [ $totalWait -gt $timeOut ]
        then
            log "timeout"
            break
        else
            sleep $waitSec
        fi
    else
        totalWait=0
        step=$(expr $step + 1)
        log "step $step"
        log "lock not present - taking control"

        log "sleeping for $waitSec secs to simulate external process"
        sleep $waitSec

        log "updating ${dataFile}.in from ${dataFile}.out"

        if [ -f "${dataFile}.out" ]
        then
            ##awk '{if( $1 != "#" ){print $1+0.1 " 0 1"}}' \
            awk '{if( $1 != "#" ){print $1 " 0 1"}}' \
                ${dataFile}.out >| ${dataFile}.in
        else
            log "Warning: no such file ${dataFile}.out"
        fi

        if [ "${stopAt:-0}" -eq $step ]
        then
            stopMasterNow
        else
            useMaster
        fi
    fi
done

log "done"

# Remove the lock file too
rm -f "$lockFile"

# For log collector:
echo "End"

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