#! /bin/ksh

function message {
    echo "$*" 1>&2
}
function die {
    message "$*"
    exit 2
}

set -x

case Q"$MP_PGMMODEL" in
    Q[mM][pP][mM][dD])
        if [[ -z "$MP_CMDFILE" ]] ; then
            die "BY GOLLY!!  You have not set the \$MP_CMDFILE variable.  Either fill one in, or use SPMD.  ABORTING"
        fi

        if [[ ! -s "$MP_CMDFILE" ]] ; then
            die "GOLLY GEE!!  Your \$MP_CMDFILE (\"$MP_CMDFILE\") is empty or non-existant.  Don't know what to do.  ABORTING"
        fi

        if [[ ! -z "$TOTAL_TASKS" ]] ; then
            them_lines=$( cat "$MP_CMDFILE" | perl -ne '/^\s*$/ and next; $x++; END { print "$x\n" }' )
            if [[ "$them_lines" != "$TOTAL_TASKS" ]] ; then
                die "WHOA NELLY!!  Your \$MP_CMDFILE (\"$MP_CMDFILE\") has $them_lines lines, but \$TOTAL_TASKS=$TOTAL_TASKS!!  You had better fix that in the kick_script.  ABORTING"
            fi
        fi

        # Run sync to ensure we're using the most up-to-date copy of
        # the command file (to get around Jet's aggressive file
        # caching):
        sync

        # For MPMD, we have to do some extra work.  The below perl
        # command generates an "mpiexec ..." command that the 'exec'
        # command will execute.
        exec $( cat "$MP_CMDFILE" | perl -ne '
            chomp;              # remove end-of-line char
            /^\s*$/ and next;   # discard blank lines
            if($#c>=0 && $c[$#c] eq $_) {
                # This command is the same as the previous, so just increment that
                # commands -np N instead of inserting a new command:
                $n[$#n]++;
            } else {
                # Add this command to the list with -np 1
                push @c, $_;
                push @n, 1;
            }
            END {
                # Now that we have read in the input, generate a command.
                print "mpiexec ";
                for($i=0; $i<=$#n; $i++) { # loop over all 
                    print "-np $n[$i] -envall $c[$i]";
                    if($i<$#n) {
                        print " : ";
                    }
                }
            }
        ' )
        ;;
    *)
        # If we're not doing MPMD, assume SPMD
        if ( echo "$1" | grep / > /dev/null ) ; then
            # Caller specified the path to an executable, so make sure
            # that executable exists, is non-empty and is executable
            if [[ ! -e "$1" ]] ; then
                message "SLIVERING SNAKES!! Your program \"$1\" does not seem to exist!  I'll try executing it anyway but this will probably fail..."
            elif [[ ! -s "$1" ]] ; then
                message "WHOPPING WILLABIES!! Your program \"$1\" seems to be empty!  I'll try executing it anyway but this will probably fail..."
            elif [[ ! -x "$1" ]] ; then
                message "BUCKING BRONCOS!! Your program \"$1\" does not seem to be executable.  I'll try executing it anyway but this will probably fail..."
            fi
        fi
        if [[ "$TOTAL_TASKS" -gt 1 ]] ; then
            exec mpiexec -envall -np "$TOTAL_TASKS" $*
        elif [[ "$TOTAL_TASKS" == 1 ]] ; then
            message "WARNING: RUNNING ONLY ONE TASK SO RUNNING IT DIRECTLY INSTEAD OF USING MPIRUN (TO WORK AROUND A JET BUG)."
            exec $*
            die "OOPES!! Unable to run $*.  ABORTING"
        else
            message "WARNING: \$TOTAL_TASKS IS NOT SPECIFIED OR IS NOT A POSITIVE NUMBER, SO I WILL NOT SPECIFY -np WHEN RUNNING mpiexec"
            exec mpiexec -envall $*
        fi
esac

# Should never get here.
exit 99