#!/bin/bash

# Set up a little bit first
FILE=background.xml
# Gonna need zenity; let's make sure we have it.
which zenity >/dev/null 2>&1
if [ $? != 0 ] ; then
	echo 'Oh no!  I couldn't find zenity!  Install it and try again.'
	exit 1
fi

# Get rid of special characters that will mess up the script and frighten small
# children.
if [ $(ls *[\`\~\!\@\#\$\%\^\&\*\(\)\{\}\[\]\;\"\'\<\>\\\?\ \	]* 2>/dev/null | wc -l) -ne 0 ] ; then
	ls *[\`\~\!\@\#\$\%\^\&\*\(\)\{\}\[\]\;\"\'\<\>\\\?\ \	]* | zenity --title "Bad bad filenames - not good" --list --text='The following files have special characters\n(perhaps including spaces and tab characters)\nin their filenames.  This will not fly.\nShould I try to fix them?' --hide-header --column="Files"
	if [ $? = 0 ] ; then
		for i in *[\`\~\!\@\#\$\%\^\&\*\(\)\{\}\[\]\;\"\'\<\>\\\?\ \	]* ; do
			mv -n "$i" $(echo $i | tr "\`\~\!\@\#\$\%\^\&\*\(\)\{\}\[\]\;\"\'\<\>\\\?\ \	" "__________________________")
		done
	else
		exit
	fi
fi
# All right, so we couldn't get rid of some; time to make the user do it his own self.
if [ $(ls *[\`\~\!\@\#\$\%\^\&\*\(\)\{\}\[\]\;\"\'\<\>\\\?\ \	]* 2>/dev/null | wc -l) -ne 0 ] ; then
	ls *[\`\~\!\@\#\$\%\^\&\*\(\)\{\}\[\]\;\"\'\<\>\\\?\ \	]* | zenity --title "Oh dear - there's an error" --list --text='The following files have special characters\n(including spaces and tab characters) in their\nfilenames.  This will not fly.  Please change the\nfilenames of the listed files.' --hide-header --column="Files"
	exit
fi

# How long does the user want each background displayed?
# First look for an old version of the XML file and get the default value out of it,
# if it exists
if [ -e $FILE ] ; then
	INCR=$(grep '<duration>' $FILE | head -1 | awk -F\> '{print $2}' | awk -F\. '{print $1}')
	INCR=$((INCR/60))
fi
if [ ! $INCR ] ; then
	INCR=5
fi
# Now, we ask for a value.
INCR=$(zenity --scale --value=$INCR --min-value=1 --max-value=60 --title "I need guidance" --text "How long (in minutes) should each background be displayed?")
if [ $? != 0 ] ; then
	exit
fi
# Convert minutes to seconds for the XML file
INCR="$((INCR * 60)).0"

# Randomize everything
NUM=$(ls *.[Jj][Pp][gG] *.[jJ][pP][eE][gG] *.[pP][nN][gG] *.[sS][vV][gG] 2>/dev/null | wc -l)
BADLIST="^$"
TMPFILE=$(mktemp)
exec 3>$TMPFILE
for (( IND=NUM ; IND >= 1 ; IND=IND-1 )) ; do
	RANDINT=$(( (RANDOM / (32767 / IND)) + 1 ))
	if [ $RANDINT -ge $IND ] ; then RANDINT=1 ; fi
	PIC=$(echo $RANDINT | select i in $(ls *.[jJ][pP][gG] *.[Pp][nN][gG] *.[jJ][pP][eE][gG] *.[sS][vV][gG] | egrep -v "$BADLIST") ; do echo $i ; break ; done 2>/dev/null)
	BADLIST="$BADLIST|^$PIC$"
	echo $PIC >&3
	#echo -e "# $PIC\n$(( 100 - ((100 * IND) / NUM) ))" #This is slow
	echo "$(( 100 - ((100 * IND) / NUM) ))"
done |
zenity --progress --title "Please stand by" --text "Randomizing backgrounds..." --percentage=0 --auto-close
if [ $? != 0 ] ; then
	exit
fi
exec 3<&-

# ---
# Now that that's out of the way, let's generate some XML!
# ---

# Miscellaneous information that goes at the beginning
cat >$FILE <<EOF
<background>
  <starttime>
    <year>2009</year>
    <month>08</month>
    <day>04</day>
    <hour>00</hour>
    <minute>00</minute>
    <second>00</second>
  </starttime>
<!-- This animation will start at midnight. -->
EOF

# And now we dump our randomized list in the XML file!  (Nicely formatted, of course.)
PICLIST=$(cat $TMPFILE)
rm -f $TMPFILE
echo $PICLIST | tr "\ " "\n" | awk -vPWD=$(pwd) -vINCR=$INCR '{
	print "  <static>"
	print "    <duration>" INCR "</duration>"
	print "    <file>" PWD"/"$0 "</file>"
	print "  </static>"
}' >>$FILE

# Finish up.  This is _important_.
echo '</background>' >>$FILE

# Should we set this as the background?
# Let's make sure it isn't already the background (because it's kinda dumb to ask to
# set it if it's already set).
SETTING=/desktop/gnome/background/picture_filename
if [ "$(gconftool --get $SETTING)" != "$(pwd)/$FILE" ] ; then
	zenity --question --title "One last thing..." --text "Set this slideshow as your background?" --ok-label "_Set as background" --cancel-label "_Cancel"
	if [ $? = 0 ] ; then
		gconftool --set $SETTING "$(pwd)/$FILE" --type string
	fi
fi