#!/bin/bash
#
# modjar.bash v0.9.2
# scribbled by Dagmar d'Surreal
# GIEF CREDIT IF STEELING... I CBA to worry about putting a licence on
# code this trivial.

show_usage () {
	echo "modjar.bash newversion.jar original.jar modfile [modfile ...]" >&2
	echo "Mods can be class files or a zip/jar file." >&2
	echo "" >&2
	exit 2
}

# To ensure filesystem tidiness
goodbye () {
	local code=${1:-0}
	rm -rf $WORKDIR $WORKTWO
	exit $code
}

[[ -z "$1" ]] && show_usage;
NEWFILE=$1 ; shift;
[[ -z "$1" ]] && show_usage;
ORIGFILE=$1 ; shift
[[ -z "$1" ]] && show_usage;
MODS=$* 

for cmd in mktemp unzip zip id chown chmod chgrp find; do
	if ! type $cmd 2>&1 >/dev/null; then
		echo "Oh dear.  You have no $cmd command.  Game over." >&2
		echo ""
		exit 1
	fi
done

WORKDIR=`mktemp -t -d modjar.XXXXXX 2>/dev/null`
if [ $? != 0 ]; then
	echo "My goodness.  mktemp failed.  You just lost the game." >&2
  echo ""
  goodbye 1
fi	
WORKTWO=`mktemp -t -d modjar.XXXXXX 2>/dev/null`
if [ $? != 0 ]; then
	echo "My goodness.  mktemp failed.  You just lost the game." >&2
  echo ""
  goodbye 1
fi	

# Now begins a long litany of things that could go wrong
if [ ! -r $ORIGFILE ]; then
	echo "Your original file must exist and be readable." >&2
	goodbye 1
fi
if [ ! -f $ORIGFILE ]; then
	echo "Your original file must be A FILE.  Ahem." >&2
	goodbye 1
fi
if [ -d $NEWFILE ]; then
	echo "Your new filename must be a filename, not a directory." >&2
	goodbye 1
fi

unzip -qq -d $WORKDIR $ORIGFILE
if [ $? != 0 ]; then
	echo "Something went wrong when unzipping $ORIGFILE." >&2
	goodbye 1
fi

for dinkyfile in $MODS; do
	if [ ${dinkyfile##*\.} == 'class' ]; then
		cp -f $dinkyfile $WORKDIR/
		if [ $? != 0 ]; then
			echo "Something went wrong when copying $dinkyfile into $WORKDIR." >&2
			goodbye 1
	  fi
	elif [ "${dinkyfile##*\.}" == 'jar' ]; then
		unzip -qq -d -f $WORKDIR $dinkyfile
		if [ $? != 0 ]; then
			echo "Something went wrong when exploding $dinkyfile into $WORKDIR." >&2
			goodbye 1
	  fi
	elif [ "${dinkyfile##*\.}" == 'zip' ]; then
		unzip -qq -d -f $WORKDIR $dinkyfile
		if [ $? != 0 ]; then
			echo "Something went wrong when exploding $dinkyfile into $WORKDIR." >&2
			goodbye 1
	  fi
	else
		echo "I have no idea what to do with $dinkyfile." >&2
		goodbye 1
	fi
done

# Now to remove the signing files...
rm -rf $WORKDIR/META-INF/*

# now for some really OCD cleanups -- these basically can't fail unless
# the system is on fire.
chown -R `id -u` $WORKDIR
chgrp -R `id -g` $WORKDIR
find $WORKDIR -type d -exec chmod 755 {} \;
find $WORKDIR -type f -exec chmod 644 {} \;

if [ -d $NEWFILE ]; then
	echo "There is already a directory named $NEWFILE.  Aborting." >&2
	goodbye 1
fi
rm -f $NEWFILE

( cd $WORKDIR
	zip -rq $WORKTWO/newfile.zip . )
if [ $? != 0 ]; then
	echo "Something went wrong creating the new file." >&2
	goodbye 1
fi
mv $WORKTWO/newfile.zip $NEWFILE









goodbye;
# vim: ts=2