#!/bin/bash

# Number of files to sum up in each iteration
CHUNKSIZE=15

TIXDIR="$1"
SUM="$TIXDIR/sum.tix"
OLDSUM="$TIXDIR/oldsum.tix"

if [ -f $OLDSUM ]
then
  echo "Error: There is an oldsum.tix file in $TIXDIR."
  exit 1
fi

tixfiles=(`find $TIXDIR -name 'darcs*.tix'`)
filesNo=${#tixfiles[@]}
i=0
while [ $i -lt $filesNo ]; do
  if [ -f "$SUM" ]
  then
    mv "$SUM" "$OLDSUM"
    declare -a oldsum=("$OLDSUM")
  else
    declare -a oldsum=()
  fi
  chunkfiles=("${tixfiles[@]:$i:$CHUNKSIZE}")
  sumfiles=("${oldsum[@]}" "${chunkfiles[@]}")

  hpc sum --union "${sumfiles[@]}" --output="$SUM"
  i=$[$i+${#chunkfiles[@]}]
  echo -n .
done
toremove=("${oldsum[@]}" "${tixfiles[@]}")
rm -f ${toremove[@]}
echo "done"