#!/bin/bash
display_help() {
    (>&2 echo "Usage: $(basename "$0") [-hv] [-f outfile] filename")
    (>&2 echo "UCF tar packer")
    (>&2 echo)
    (>&2 echo "   filename                path to arbitrary file with correct sequence number")
    (>&2 echo "   -f, --file              output file (default: snapshot_XXXX.ucf.tar)")
    (>&2 echo "   -h, --help              display this help message")
    (>&2 echo "   -v, --verbose           verbose output")
}
exit_script() {
    #trap - SIGINT SIGTERM  # clear the trap
    #kill -- -$$            # Sends SIGTERM to child/sub processes
    (>&2 echo "SIGINT/SIGTERM received: removing archive")
    rm $fout
}
# Parse command line arguments
if [ $# -eq 0 ]; then
  display_help
  exit -1
fi
fout=""
verbose=0
POSITIONAL=()
while [[ $# -gt 0 ]]
do
key="$1"
case $key in
    -h|--help)
    display_help
    exit 0
    shift # past argument
    ;;
    -f|--file)
    fout="$2"
    shift # past argument
    shift # past value
    ;;
    -v|--verbose)
    verbose=1
    shift # past argument
    ;;
    *)    # unknown option
    POSITIONAL+=("$1") # save it in an array for later
    shift # past argument
    ;;
esac
done
set -- "${POSITIONAL[@]}"

# Parse input filename
din=$(dirname $1)
fin=$(basename $1)
seqnum=$(echo $fin | grep -o '_[0-9]\+')
if [ -z "$seqnum" ]; then
  (>&2 echo "[Error] No sequence number found in input filename.")
  exit 1;
fi

# Construct output filename if not specified
if [ -z "$fout" ]; then
  fout="snapshot${seqnum}.ucf.tar"
fi

# Display verbose info
if [ $verbose -eq 1 ]; then
  (>&2 echo "Creating archive: $fout")
fi

# Check input files
fparam="parameters${seqnum}.asc"
fgrid="grid${seqnum}.bin"
fproc="proc${seqnum}.bin"
fpart="particles${seqnum}.bin"
fbuvwp="uvwp"
fbscal="scal"

# Check if obligatory files are present
if [ ! -s ${din}/${fparam} ]; then
  (>&2 echo "[Error] File not found or empty: ${din}/${fparam}")
  exit 1
fi
if [ ! -s ${din}/${fgrid} ]; then
  (>&2 echo "[Error] File not found or empty: ${din}/${fgrid}")
  exit 1
fi
if [ ! -s ${din}/${fproc} ]; then
  (>&2 echo "[Error] File not found or empty: ${din}/${fproc}")
  exit 1
fi
if [ ! -s ${din}/${fpart} ]; then
  (>&2 echo "[Error] File not found or empty: ${din}/${fpart}")
  exit 1
fi

# Check if all velocity fields exist and are not empty
nproc=$(cat ${din}/${fparam} | grep "nprocs" | awk '{print $NF}')
if [ $verbose -eq 1 ]; then
  (>&2 echo "Number of processors: $nproc")
fi

fuvwp=()
for (( ii=0; ii<$nproc; ii++ )); do
  ftmp=$(printf uvwp${seqnum}.%05d $ii)
  if [ ! -s ${din}/${ftmp} ]; then
    (>&2 echo "[Error] File not found or empty: ${din}/${ftmp}")
    exit 1
  fi
  fuvwp+=($ftmp)
done

# Check if all scalar fields exist (if any) and are not empty
if grep -q "scalar" "${din}/${fparam}"; then
  fscal=()
  for (( ii=0; ii<$nproc; ii++ )); do
    ftmp=$(printf scal${seqnum}.%05d $ii)
    if [ ! -s ${din}/${ftmp} ]; then
      (>&2 echo "[Error] File not found or empty: ${din}/${ftmp}")
      exit 1
    fi
    fscal+=($ftmp)
  done
fi

# Verbose info
if [ $verbose -eq 1 ]; then
  (>&2 echo "[x] parameters")
  (>&2 echo "[x] grid")
  (>&2 echo "[x] processor grid")
  (>&2 echo "[x] particles")
  (>&2 echo "[x] fluid fields")
  if [ ${#fscal[@]} -ne 0 ]; then
    (>&2 echo "[x] scalar fields")
  else
    (>&2 echo "[ ] scalar fields")
  fi
fi

# Now tar them and remove seqence number from file names while doing so
if [ $verbose -eq 1 ]; then
  flagtar="-v"
fi
trap exit_script SIGINT SIGTERM
tar $flagtar --format ustar --transform="flags=r;s|$seqnum||" --directory=${din} -cf ${fout} ${fparam} ${fgrid} ${fproc} ${fpart} ${fuvwp[@]} ${fscal[@]}
tarexit=$?
# Set exit status accoring to tar
if [ $tarexit -ne 0 ]; then
  (>&2 echo "tar failed with exit code $tarexit")
  exit 254
fi
exit 0