#!/bin/bash

if [ "$#" != 1 ]; then
 echo "usage: $0 firstrarfile"
 exit 1
fi

PAR2=/usr/bin/par2
RAR=/usr/bin/rar
SPLIT=/usr/bin/split

FIRSTRAR="$1"
if [ "$FIRSTRAR" != `basename $FIRSTRAR .part001.rar` ]; then
 BASENAME=`basename "$FIRSTRAR" .part001.rar`
 NUMRARS=`ls ${BASENAME}.part*.rar | wc -l | awk '{print $1;}'`
 PRINTF="\"mv ${BASENAME}.%02d ${BASENAME}.part%03d.rar\n\" \$i \$((\$i+1))"
elif [ "$FIRSTRAR" != `basename $FIRSTRAR .part01.rar` ]; then
 BASENAME=`basename "$FIRSTRAR" .part01.rar`
 NUMRARS=`ls ${BASENAME}.part*.rar | wc -l | awk '{print $1;}'`
 PRINTF="\"mv ${BASENAME}.%02d ${BASENAME}.part%02d.rar\n\" \$i \$((\$i+1))"
else
 BASENAME=`basename "$FIRSTRAR" .rar`
 NUMRARS=`ls ${BASENAME}.r?? | wc -l | awk '{print $1;}'`
 PRINTF="\"mv ${BASENAME}.%02d ${BASENAME}.r%02d\n\" \$i \$((\$i-1))"
fi
MAXBLOCKS=32565
BLOCKS=$(($NUMRARS*2))
RARSIZE=`du -b ${FIRSTRAR} | awk '{print $1;}'`

FILELIST=`"$RAR" lb "$FIRSTRAR"`

"$RAR" x "$FIRSTRAR"
rm -f *par2 *PAR2
"$PAR2" c -b${MAXBLOCKS} -c${BLOCKS} -n1 -t+ "${BASENAME}.par2" *rar *r??

cat >> rerar.sh << EOF
#!/bin/bash
$SPLIT -b$RARSIZE -d ${FILELIST} ${BASENAME}.
mv ${BASENAME}.00 ${FIRSTRAR}
for i in \`seq 1 $(($NUMRARS-1))\`; do \`printf $PRINTF\`; done
"$PAR2" r ${BASENAME}.par2
rm ${BASENAME}.*.1
EOF

chmod +x rerar.sh