#!/bin/sh

set -e

curr_ver=$(ls g10-*.tar.gz | sort -r -t '.' -n +0.4 -1 +1 -2 +2 \
	   | head -1 | sed -e 's/g10-\(.*\).tar.gz/\1/' )
prev_ver=$(ls g10-*.tar.gz | sort -r -t '.' -n +0.4 -1 +1 -2 +2 \
	   | head -2 | tail -1 | sed -e 's/g10-\(.*\).tar.gz/\1/' )

echo "Current  is: $curr_ver"
echo "Previous is: $prev_ver"

echo "Removing old directories"
[ -d "g10-$curr_ver" ] && rm -rf "g10-$curr_ver"
[ -d "g10-$prev_ver" ] && rm -rf "g10-$prev_ver"

echo "Unpacking previous and current tar"
tar xzf "g10-$curr_ver.tar.gz"
tar xzf "g10-$prev_ver.tar.gz"


echo "Diffing"
tmp_name="g10-$curr_ver.diff.tmp"
diff_name="g10-$curr_ver.diff"

diff -urN "g10-$prev_ver/" "g10-$curr_ver/"  > $tmp_name || true

echo "Making patch file"

cat <<EOF > $diff_name

This is a patch file against $prev_ver.

Change to directory g10-$prev_ver (or however you renamed it)
and give this command:

     zcat somepath/g10-$curr_ver.diff.gz | patch -p1

It is a good idea to rename your current directory to g10-$curr_ver now.



Prereq: $prev_ver

EOF

sed -ne '/^diff.*VERSION/,/^+[0-9][0-9]*/ p' $tmp_name >> $diff_name
echo  >> $diff_name
sed -e '/^diff.*VERSION/,/^+[0-9][0-9]*/ d'  $tmp_name >> $diff_name

rm $tmp_name

echo "Compressing patch file"
gzip -9 $diff_name

echo "Checking patch file"
cd g10-$prev_ver
zcat ../$diff_name.gz | patch -s -p1
rm $(find . -name "*.orig")
cd ..

if ! diff -urN "g10-$prev_ver/" "g10-$curr_ver/" >/dev/null ; then
   echo "compare failed"
   exit 1
fi


echo "cleaning up"

rm -rf "g10-$curr_ver"
rm -rf "g10-$prev_ver"

echo "Patch file $diff_name.gz is good."