#!/bin/sh

#set -e

basedir="/etc"
targetdir="/tmp/localtweaks"
includefile="/etc/local/localtweaks.include"
excludefile="/etc/local/localtweaks.exclude"
extensions=".orig .old"

for ext in $extensions; do
	extfiles="`find $basedir -name \*$ext`"
	for extfile in $extfiles; do
		xextfile="${extfile%$ext}"
		files="$files ${xextfile#$basedir}"
	done
done

includes=""
if [ -d "`dirname $includefile`" ] && [ -r $includefile ]; then
	includes="`cat $includefile`"
	for include in $includes; do
		files="$files ${include#$basedir}"
	done
fi

excludes=""
if [ -d "`dirname $excludefile`" ] && [ -r $excludefile ]; then
	xexcludes="`cat $excludefile`"
	for exclude in $xexcludes; do
		excludes="$excludes ${exclude#$basedir}"
	done
fi

# process all files once each
for file in `for x in $files; do echo $x; done | uniq | sort`; do

	# file were chosen based on backups - it may not exist itelf
	[ -s "$basedir/$file" ] || continue

	for exclude in $excludes; do
		[ "$file" = "$exclude" ] && continue 2
	done

	ext=""
	for xext in $extensions; do
		if [ -e $basedir/$file$xext ]; then
			ext="$xext"
			continue
		fi
	done

	newdir="$targetdir/$basedir/`dirname $file`"
	mkdir -p $newdir
	cp -af $basedir/$file $newdir

	# Only diff against existing and non-empty files.
	if [ -n "$ext" ] && [ -s $basedir/$file$ext ]; then
		diff -ruN $basedir/$file$ext $basedir/$file > $targetdir/$basedir/$file.diff
		chown --reference=$basedir/$file $targetdir/$basedir/$file.diff
		chmod --reference=$basedir/$file $targetdir/$basedir/$file.diff
		chmod a-x $targetdir/$basedir/$file.diff
	fi
done