#!/bin/rc
# pim/fetch -- refresh a subscribed calendar from its url.
#
#	pim/fetch $home/lib/cal/work.url $home/lib/cal/work.ics \
#		/mnt/pim/calendars/work/ctl
#
# ical/fs does not fetch: a subscribed calendar is a file somebody else
# wrote. This is that somebody. It writes the file only when the content
# actually changed, then pokes ctl so the server reloads at once instead
# of waiting to notice.
#
# The url of a private calendar is a secret, so it is read from a file
# rather than passed as an argument where ps(1) would show it.
rfork e

if(! ~ $#* 2 && ! ~ $#* 3){
	echo 'usage: fetch urlfile dest.ics [ctl]' >[1=2]
	exit usage
}
urlfile=$1
dest=$2
ctl=$3

if(! test -r $urlfile){
	echo 'pim/fetch: cannot read '^$urlfile >[1=2]
	exit nourl
}
url=`{sed -n '/^#/d; /^$/d; s/["'']//g; p; q' $urlfile}
if(~ $#url 0){
	echo 'pim/fetch: no url in '^$urlfile >[1=2]
	exit nourl
}

tmp=$dest.new
if(! hget $"url > $tmp){
	rm -f $tmp
	echo 'pim/fetch: fetch failed' >[1=2]
	exit fetch
}
if(! test -s $tmp){
	rm -f $tmp
	echo 'pim/fetch: empty response' >[1=2]
	exit empty
}

# a fetch that changes nothing must not rebuild the tree or wake watchers
if(test -f $dest)
	if(cmp -s $tmp $dest){
		rm -f $tmp
		exit 0
	}
mv $tmp $dest
if(! ~ $#ctl 0)
	if(test -f $ctl)
		echo refresh >$ctl
exit 0