#!/bin/sh
# Copyright: 2008 Sasa Bodiroza <jazzva@gmail.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2, or (at
# your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

DIR=$1;
CUR_DIR=`pwd`;

if [ -z $DIR ] ; then
	echo "Missing directory.\n";
	exit 1;
fi;

cd $DIR;
NUM=`find -maxdepth 1 -type f -regex ".+\.\(jpg\|jpeg\|gif\|png\|svg\)" -printf "%f\n" | wc -l`

if [ $NUM -eq 0 ] ; then 
	echo "Empty dir";
	exit 1;
fi

INC=`expr 1440 \/ $NUM`;
MOD=`expr 1440 \% $NUM`;

CNT=1;
CNT_MIN=0;

while [ 1 ] ; do
	MIN=`date +%M`;
	HOUR=`date +%k`;
	CUR_MIN=`expr $MIN + $HOUR \* 60`;
	while [ $CNT -le $NUM ] ; do
		if [ $CUR_MIN -ge $CNT_MIN -a $CUR_MIN -lt `expr $CNT_MIN + $INC` ] ; then
			FILE=`pwd`/`find -maxdepth 1 -type f -regex ".+\.\(jpg\|jpeg\|gif\|png\|svg\)" -printf "%f\n" | sort | grep -n "" | grep "^$CNT" | cut -d: -f2`;
#			echo $FILE;
			gconftool-2 --type string --set /desktop/gnome/background/picture_filename "$FILE";
			CNT=`expr $CNT + 1`;
			CNT_MIN=`expr $CNT_MIN + $INC`;
			break;
		fi
		CNT=`expr $CNT + 1`;
		CNT_MIN=`expr $CNT_MIN + $INC`;
	done
	if [ $MOD -ne 0 -a $CNT -gt $NUM ] ; then
		sleep `expr 1440 - $CUR_MIN`m;
	else
		sleep `expr $CNT_MIN - $CUR_MIN`m;
	fi
	if [ $CNT -gt $NUM ] ; then
		CNT=1;
		CNT_MIN=0;
	fi
done