#!/bin/sh

# The directory in which to find the last snapshot; must be absolute path
dir=/home/mccallum/gnu/releases

# The email addresses of people to receive mail about the new diff
diff_recipients=gnustep-dev@prep.ai.mit.edu

# The name of this module
module=gstep-base
# A regular expression for the version string "x.y.z"
yrptn='[0-9][0-9][0-9][0-9][0-9][0-9]'
# The pattern for the file containing the diff
ptn="${module}-${yrptn}"
dptn="${ptn}-${yrptn}.diff"

# Get the current version
. Version

# Find date of the last snapshot
lastdist=${VERSION}

# This depends on the user setting this variable from the command line
if [ -z $OLD ]; then
  echo You must set the shell variable OLD to the old version number.
  exit -1
fi
secondlastdist=${OLD}

echo Making diff between $secondlastdist and $lastdist

# The name of the diff file
diff="${module}-${secondlastdist}-${lastdist}.diff"

if [ -f $dir/$diff ]; then
  echo $dir/$diff already exists!  Exiting.
  exit -1
fi
echo Making $diff

# Untar the old dist
(cd /tmp ; tar -zvxf $dir/${module}-${secondlastdist}.tar.gz)
# Untar the new dist
(cd /tmp ; tar -zvxf $dir/${module}-${lastdist}.tar.gz)
# Make the diff
echo Diffing...
rm -f /tmp/$diff
(cd /tmp; diff -u -r ${module}-${secondlastdist} ${module}-${lastdist} > $diff)
# Remove the dist dirs
rm -rf /tmp/${module}-${secondlastdist} /tmp/${module}-${lastdist}

if [ -s /tmp/$diff ]; then
  # Mail a message saying the new diff is available. (Commented out for now)
  # mail -s $diff < $diff $diff_recipients
  gzip -9 /tmp/$diff && mv -f /tmp/$diff.gz $dir
else
  rm -f /tmp/$diff
fi