#!/bin/sh
# Copyright (C) 2005,2006 Krzysztof Kozlowski
#   License: GNU General Public License version 2
#            http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# version 2 as published by the Free Software Foundation.
#
# 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.
#
# Homepage: http://www.kozik.net.pl
#
# Ostatnia zmiana: 4.10.2006
#
# Change GNOME wallpaper to random one chosen from a directory
#

# Zmienne :
USER="kozik"
DIR="/home/${USER}/Spoko/Tapety/sentences" # Dir with wallpapers

GNOME_WALLPAPER_FILE="/home/${USER}/.gconf/desktop/gnome/background/%gconf.xml"


WALLPAPERS=`ls $DIR`
if [ $? -ne 0 ]; then
  echo "Error reading directory $DIR"
  exit 1
fi
MAX_WALLPAPER=`ls $DIR | wc -l`
if [ $? -ne 0 ]; then
  echo "Error reading directory $DIR"
  exit 1
fi

# Poszukiwanie zsh lub bash (shelle, ktore rozumieja skladnie "echo $RANDOM")
GOOD_SHELL=`which zsh 2> /dev/null`
if [ ! -f "GOOD_SHELL" ]; then
  GOOD_SHELL=`which bash 2> /dev/null`
  if [ ! -f "GOOD_SHELL" ]; then
    if [ -f "/usr/local/bin/zsh" ]; then
      GOOD_SHELL="/usr/local/bin/zsh"
    elif [ -f "/usr/bin/zsh" ]; then
      GOOD_SHELL="/usr/bin/zsh"
    elif [ -f "/bin/zsh" ]; then
      GOOD_SHELL="/bin/zsh"
    elif [ -f "/usr/local/bin/bash" ]; then
      GOOD_SHELL="/usr/local/bin/bash"
    elif [ -f "/bin/bash" ]; then
      GOOD_SHELL="/bin/bash"
    else
      echo "Nie znalazlem interesujacego shella potrafiacego generowac losowe liczby"
      exit 3 ;
    fi
  fi
fi
# ############################################

# Get a random number :
TEXT="\$RANDOM"
number=`$GOOD_SHELL -c "echo $TEXT"`
# Truncate number to number of wallpapers in our directory :
let "number %= $MAX_WALLPAPER"

# ############################################

# Do the loop :
count=0
NEW_WALLPAPER=""
for i in $WALLPAPERS; do
  count=`expr $count + 1`
  if [ $count -ne $number ]; then
    continue
  else
    NEW_WALLPAPER=$i
    break
  fi
done

# ############################################

# Replace text:
#    <stringvalue>WALLPAPER</stringvalue>
# between:
#    <entry name="picture_filename" mtime="" schema="" type="string">
# and
#    </entry>

echo "Setting $NEW_WALLPAPER wallpaper..."
NEW_WALLPAPER_PATH=`echo "${DIR}/${NEW_WALLPAPER}"`
# 
cat $GNOME_WALLPAPER_FILE | sed -e "/<entry.\{1,\}name=\"picture_filename\".*>/,/<\/entry>/ s_<stringvalue>.*<\/stringvalue>_<stringvalue>$NEW_WALLPAPER_PATH<\/stringvalue>_" > ${GNOME_WALLPAPER_FILE}.tmp
if [ $? -eq 0 ]; then
  mv ${GNOME_WALLPAPER_FILE}.tmp $GNOME_WALLPAPER_FILE
  exit 0
else
  rm ${GNOME_WALLPAPER_FILE}.tmp
  echo "Blad przy zmianie tapety"
  exit 1
fi