#! /bin/sh

# This script uses rsync to create an rsync batch file to re-create
# the first argument out of the remaining arguments.  It also creates
# a shell script to re-create the file.  If --verify is the first
# argument, then the resulting rsync file will be verified to be
# usable to re-create the original file.

# Copyright 2005 Alexandre Oliva <oliva@lsd.ic.unicamp.br>

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

verify=false
case $1 in
--verify)
  verify=:
  shift
  ;;
esac

target=$1
shift || exit 1

if test $# = 0; then
  echo no input files for the rsync batch >&2
fi

if test ! -f "$target"; then
  echo "$target" does not exist >&2
  exit 1
fi

if test -f "$target".orig; then
  echo "$target".orig already exists >&2
  exit 1
fi

if test -f "$target".new; then
  echo "$target".new already exists >&2
  exit 1
fi

if test -f "$target".rsync; then
  echo "$target".rsync already exists >&2
  exit 1
fi

set -e

if test -f "$target".cat; then
  echo "$target".cat already exists, assuming it is correct >&2
else
  case $# in
  1) ln "$@" "$target".cat ;;
  *) cat "$@" > "$target".cat ;;
  esac
fi

ln "$target".cat "$target".new
rsync -av --progress --write-batch="$target".rsync "$target" "$target".new

bzip2 -9 < "$target".rsync > "$target".rsync.bz2
rm -f "$target".new "$target".rsync.sh "$target".cat "$target".rsync

cat > "$target".sh << EOF
#! /bin/sh
set -e

cd \`dirname \$0\`
target=\`basename \$0 .sh\`

if test -f "\$target"; then
  echo "\$target" already exists, entering test mode >&2
fi

if test -f "\$target".new; then
  echo "\$target".new already exists >&2
  exit 1
fi

if test -f "\$target".cat; then
  echo using existing "\$target".cat, will remove at the end >&2
else
EOF

case $# in
1) echo "  ln \"$@\" \"\$target\".cat" ;;
*) echo "  cat" "$@" \> \"\$target\".cat ;;
esac >> "$target".sh

cat >> "$target".sh <<EOF
fi

ln "\$target".cat "\$target".new

bunzip2 < "\$target".rsync.bz2 |
  rsync -av --progress --read-batch=- "\$target".new

status=0

if test -f "\$target"; then
  if cmp "\$target".new "\$target"; then
    echo cmp "\$target".new "\$target" passed >&2
  else
    status=$?
    echo cmp "\$target".new "\$target" failed >&2
  fi
  rm -f "\$target".new
else
  mv "\$target".new "\$target"
fi

rm -f "\$target".cat
exit $status
EOF

chmod +x "$target".sh

echo "$target".sh and "$target".rsync.bz2 created successfully >&2

if $verify; then
  mv "$target" "$target".orig
  echo "$target" renamed to "$target".orig

  if sh "$target".sh && cmp "$target".orig "$target"; then
    status=0
  else
    echo "$target".rsync.bz2 appears to be bad >&2
    status=1
  fi
else
  status=0
fi

exit $status