#!/bin/bash
#
# purpose : use random image from gnome art (art.gnome.org) as a wallpaper
# author  : kyanh <xkyanh_com_gmail>
# license : gpl (version 2)
# version : $Id: gnome-art 3645 2009-05-30 22:30:21Z pi $
# requires: lynx, feh, awk, bash
# homge   : http://viettug.org/projects/show/fs (please search there)
# custom  :
#    * _SET_BACKGROUND : a program to set wallpaper using image url
#    * _RESOLUTION     : environment to provide resoultion match (default: 1024x)
# option  :
#    * --update        : update the cache file $HOME/.gnome-art.log
#
# notes   :
#    This program will use a cache file ($_tempfile, see below) to save
#    the list of image URLs. You will use any program to get a random
#    url from this list and set the desktop background using that url.
#    To update the cache file, use --update option. The program also
#    update the cache automatically if it found nothing in cache.
#    You'll need a internet connection and wait for a while if you
#    want to update stuff. *DO NOT* modify the cache file manually
#    as your changes may be overriden.
#

_SET_BACKGROUND="feh --bg-center"
_resolution=${_RESOLUTION:-1024x}

_src=http://ftp.gnome.org/pub/GNOME/teams/art.gnome.org/backgrounds/
_tempfile="$HOME/.gnome-art.log"

_msg() {
	echo -e ":: $*"
	return 1
}

_ignore_spaces() {
	tr -d '[ \t]'
}

_update() {
        _msg "updating the list of image (please wait)"
        lynx -dump $_src \
                | grep http:// \
                | grep $_resolution \
                | awk '{print $2}' \
		| sort -u \
                > $_tempfile
	_msg "(done)"
}

touch $_tempfile || _msg "cannot create temporary file $_tempfile. exit 1" || exit 1

_image_count="$(wc -l < $_tempfile | _ignore_spaces)"
_msg "found $_image_count image(s) in cache file $_tempfile (precheck)"

if test "x$1" == "x--update"; then
	_update
elif test $_image_count -eq 0; then 
	_update
fi

_image_count=$(wc -l < $_tempfile | _ignore_spaces)
_msg "found $_image_count image(s) in cache file $_tempfile"

if test $_image_count -gt 0; then
	_image_random=$((RANDOM % _image_count + 1))
	_image_url=$(cat $_tempfile | head -"$_image_random" | tail -1)
        _msg "going to use the random image $_image_random"
	_msg "image url = $_image_url"
	$_SET_BACKGROUND $_image_url
fi