#!/bin/sh
#
# downloads xkcd comics
#

DOWNLOADDIR=$HOME/Ebooks/xkcd/

download_xkcd ()
{
	NUMBER=$1

	if [ `ls -1 | grep -c "^${NUMBER}_"` -gt 0 ] || [ $NUMBER -eq 404 ];
	then
		return 0
	fi

	# LINE_URL may contain link to larger comic at beginning
	LINE_URL=`wget http://xkcd.com/$NUMBER/ -q -O - | grep "<img src=.*title=.*alt="`
	URL=`echo $LINE_URL | cut -d '"' -f 2`
	LINE_IMG=`echo $LINE_URL | sed 's/.*\(<img src=.*\)/\1/'`
	#TITLE=`echo $LINE_IMG | cut -d '"' -f 4`
	#ALT=`echo $LINE_IMG | cut -d '"' -f 6`

	# url leads to an external site
	if [ `echo $URL | grep -c "^http://imgs.xkcd.com/comics/"` -eq 0 ];
	then
		URL=`echo $LINE_IMG | cut -d '"' -f 2`
	fi

	FILENAME="${NUMBER}_`echo $URL | cut -d '/' -f 5`"

	echo -n "Downloading xkcd #$NUMBER"
	wget $URL -q -O $FILENAME
	# does not work with jpg
	#mogrify -comment "$TITLE" $FILENAME
	echo "."

	return 0
}


if [ ! -d $DOWNLOADDIR ];
then
	echo "Creating download directory $DOWNLOADDIR"
	mkdir -p $DOWNLOADDIR
fi

cd $DOWNLOADDIR

CURRENT=`wget http://xkcd.com/ -q -O - | grep "Permanent link to this comic: " | cut -d '/' -f 4`

for i in `seq $CURRENT -1 1`;
do
	download_xkcd $i
done