#!/bin/sh

set -e

targetdir=/tmp/localtweaks

origfiles="`cd /etc && find . -name '*.orig'`"
oldfiles="`cd /etc && find . -name '*.old'`"
includes=""
excludes=""
if [ -d /etc/local ]; then
	if [ -r /etc/local/localtweaks.include ]; then
		includes="`cat /etc/local/localtweaks.include`"
	fi
	if [ -r /etc/local/localtweaks.exclude ]; then
		excludes="`cat /etc/local/localtweaks.exclude`"
	fi
fi

files="$origfiles $oldfiles $includes"

# process all *.{orig,old} once each
for file in `for x in $files; do echo $x; done | uniq | sort`; do
	olddir="/etc/`dirname $file`"
	newdir="$targetdir/`dirname $file`"
	oldname="`basename $file`"
	newname="`basename $file .orig`"
	for exclude in $excludes; do
		[ "$newname" = "$exclude" ] && continue 2
	done
	if [ ! -e $olddir/$newname.orig ]; then
		newname="`basename $file .old`"
	fi
	if [ "$oldname" = "$newname" ]; then
		echo "FATAL: file is neither .orig nor .old: \"$file\"!"
		exit 1
	fi
	if [ ! -e $olddir/$oldname ]; then
		echo "FATAL: file found disappeared again: \"$file\"!"
		exit 1
	fi
	mkdir -p $newdir
	cp -af $olddir/$newname $newdir

	# Only diff against non-empty files.
	if [ -s $olddir/$oldname ]; then
		diff -ruN $olddir/$oldname $olddir/$newname > $newdir/$newname.diff
		chown --reference=$olddir/$newname $newdir/$newname.diff
		chmod --reference=$olddir/$newname $newdir/$newname.diff
		chmod a-x $newdir/$newname.diff
	fi
done