#!/bin/bash
#
# 	original idea  GNU (C) by Peter Klausner 2003
#
#	completely rewritten by Jens Röder j.roeder@tu-bs.de   29.03.2005
#	
#	original was not working because slashes in file names
#	additionaly TWiki-Authentication was included
#	now, the directory structure of a TWiki is mirrored in the cache
#
#	
# Function:	
#	script-chooser to decide, if a Topic needs to be rerendered
#	or supplied from cache.
#
# Installation:
#	copy 'cache' into TWiki bin/ directory.
#	mv view render
# 	ln -s cache view
#	ln -s cache refresh
#	mkdir cache in TWiki main directory
#
# See also:
#	Foswiki:Extensions/CacheChooserAddOn
#
#
# customize if directories in your TWiki are different from standard installation tree:
data=${PWD%bin}/data
cache=${PWD%bin}/cache
errlog=$cache/.htcacherr.log
twikipref=$data/TWiki/DefaultPreferences.txt
#
# debug:
#exec 2>/tmp/cacherun
#set -x
#set >/tmp/cachevar

[ ! "$PATH_INFO" ] && [ "$@" ] && PATH_INFO=$@

if [ ! "$PATH_INFO" ] || [ "$PATH_INFO" == "/" ] ; then
NEWPATH=`grep 'Set WIKILOGOURL = http:' $twikipref | cut -d= -f2`
NEWPATH=${NEWPATH#*/view/}
: ${NEWPATH:=Main/WebHome}
PATH_INFO="/$NEWPATH-start"
fi

[ "$QUERY_STRING" ] && QUERY="?$QUERY_STRING"

case $HTTPS in

	[oO][nN])
		cache=$cache/ssl-cache
		;;
esac

entry="$cache$PATH_INFO$QUERY"

datafile="$data$PATH_INFO.txt"
webpref="$data${PATH_INFO%/*}/WebPreferences.txt"

[ "$QUERY_STRING" ] && case $QUERY_STRING in

	skin=plain)
		echo -n
		;;
	
	*refresh=cache*)
		QUERY_STRING=${QUERY_STRING//refresh=cache'\&'/}
		QUERY_STRING=${QUERY_STRING//refresh=cache/}
		REQUEST_URI=${REQUEST_URI//refresh=cache'\&'/}
		REQUEST_URI=${REQUEST_URI//'\?'refresh=cache/}
		entry=${entry//refresh=cache'\&'/}
		entry=${entry//'\?'refresh=cache/}
		rm -f $entry
		;;

	*sortcol=*)
		echo -n
		;;
	*)
		AVOIDCACHING=1
		;;
esac

if [ "$AVOIDCACHING" ] ; then
CHOOSE=1
else

[ -f $entry ] && checkentry=$entry

Z=0
for D in `grep -c -h -e '^[lL]ocation: http://' -e 'Set CACHE = [a-zA-Z0-9]' -e 'Set NOCACHE' -e 'Set .*TOPICVIEW = [a-zA-Z].*' -e 'Set .*WEBVIEW = [a-zA-Z].*' $datafile $webpref $checkentry` ; do

	Z=$(( $Z + $D ))
done

FILESTATE=
[ "$entry" -nt "$data/$PATH_INFO.txt" ] && FILESTATE=nonewer

CHOOSE=0
[ ! "${0##*/}" = refresh ] && [ "$FILESTATE" ] && CHOOSE=-1
[ "$Z" -gt "0" ] && CHOOSE=1

if [ "$Z" -gt "0" ] ; then

if [  "$checkentry" ] ; then
[ "`grep -c -h -e '[lL]ocation: http://' $checkentry`" -gt "0" ] && CLEARCACHE=1
fi

TIME=0
for D in "`grep -h -e 'Set CACHE = [a-zA-Z0-9].*' $webpref $datafile `" ; do

DAT=${D##*Set CACHE = }
DAT=${DAT%%\ *}

for DA  in ${DAT//-/ } ; do

case "$DA" in

        cache)
		SETCACHE=y
		;;
	daily)
		DAYSTART='-daystart'
		TIME='1440'
		;;

        [1-9]m)
                TIME=$(( $TIME + ${DA%m} ))
                ;;

        [1-5][0-9]m)
                TIME=$(( $TIME + ${DA%m} ))
                ;;

        [1-9]h)
                TIME=$(( $TIME + ${DA%h} * 60 ))
                ;;

        [1-2][0-9]h)
                TIME=$(( $TIME + ${DA%h} * 60 ))
                ;;

        [1-6]d)
                TIME=$(( $TIME + ${DA%d} * 60 * 24 ))
                ;;

        [1-9]w)
                TIME=$(( $TIME + ${DA%w} * 60 * 24 * 7 ))
                ;;
        [1-9]M)
                TIME=$(( $TIME + ${DA%M} * 60 * 24 * 31 ))
                ;;

        [1][0-9]M)
                TIME=$(( $TIME + ${DA%M} * 60 * 24 * 31 ))
                ;;
	*)
		DATE=`date`
		echo "$DATE :: Error $datafile :: $DA" >> $errlog
		;;
esac

done
done

if [ "$TIME" -gt "0" ] || [ "$SETCACHE" ] ; then

ZC=0
                for D in `grep -c -h -e 'Set .*TOPICVIEW = [a-zA-Z].*' -e 'Set .*WEBVIEW = [a-zA-Z].*'  $datafile $webpref ` ; do
                ZC=$(( $ZC + $D ))
                done
                [ "$ZC" -eq "0" ] && CACHE=y
                [ "$ZC" -gt "0" ] && CACHE=n
fi

[ ! "$CACHE" = "n" ] && [ "$TIME" -gt "0" ] && [ ! "`find $entry $DAYSTART -mmin -$TIME `" ] && NEWCACHE=new

[ "$CACHE" = "y" ] && CHOOSE=0
[ "$CACHE" = "y" ] && [ ! "${0##*/}" = refresh ] && [ "$FILESTATE" ] && CHOOSE=-1
[ "$NEWCACHE" = "new" ] && CHOOSE=0
[ "$CACHE" = "n" ] && CHOOSE=1 
fi

[ "$CLEARCACHE" ] && [ "$CHOOSE" -lt "0" ] && CHOOSE=0

fi


if [ "$CHOOSE" -gt "0" ] ; then
	rm -f "$entry"
	exec ./render "$@" 2>/dev/null

elif [ "$CHOOSE" -lt "0" ] ; then

	exec cat "$entry"

else
	[ "$CLEARCACHE" ] && rm -f "$entry"
	mkdir -p ${entry%/*}
	exec ./render "$@" | tee "$entry" 2>/dev/null
fi