pim: invite, and a way to say what you mean

pim/invite makes an event and, when it names attendees, sends the
invitation -- which on a caldav server with auto-schedule is the same
act. -p writes the object to standard output instead, so it can go to
upas/marshal as iMIP, into a directory an ical/fs is serving, or
nowhere in particular. There is no separate verb for inviting because
to a calendar there is no separate thing.

It writes the tree's own key: value form rather than icalendar. The
first version spelled SUMMARY: by hand and got "lunch, then a walk"
wrong: a comma is a separator there and wants escaping. Parsing with
go-ical and generating by hand is the wrong asymmetry, so calfs grew
Compose, and now the same shape the tree emits is the shape it accepts.
The one UID we ever mint -- as organiser we own the event -- is minted
there too.

pim/invites lists what is waiting for an answer, which is what makes
pim/rsvp usable: it walks the date tree rather than every event, since
an invitation you never answered last March is not news.

agenda and show take -d date now, via seconds(1), which parses a human
date where date(1) only formats one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/pim/rc/rsvp b/pim/rc/rsvp
new file mode 100755
index 0000000..0e21f04
--- /dev/null
+++ b/pim/rc/rsvp
@@ -0,0 +1,111 @@
+#!/bin/rc
+# pim/rsvp -- answer an invitation.
+#
+#	pim/rsvp accepted 'meet with ben'
+#	pim/rsvp declined /mnt/pim/calendars/work/events/date/2026/08/24/1000-API-WG
+#
+# Takes an occurrence path, as pim/agenda -p prints and cal9 plumbs, or a
+# pattern to search for. The answer goes to the event's partstat, and
+# what happens next is the backend's business: a caldav server with
+# calendar-auto-schedule updates your copy and mails the organiser, and
+# a published .ics refuses outright, which is the honest answer there.
+rfork e
+
+mtpt=/mnt/pim
+days=90
+only=()
+
+while(~ $1 -*){
+	switch($1){
+	case -m
+		mtpt=$2; shift
+	case -c
+		only=($only $2); shift
+	case -n
+		days=$2; shift
+	case *
+		echo 'usage: rsvp [-m mtpt] [-c cal] [-n days] accepted|declined|tentative path|pattern' >[1=2]
+		exit usage
+	}
+	shift
+}
+if(test $#* -lt 2){
+	echo 'usage: rsvp [-m mtpt] [-c cal] [-n days] accepted|declined|tentative path|pattern' >[1=2]
+	exit usage
+}
+
+want=`{echo $1 | tr a-z A-Z}
+shift
+switch($want){
+case ACCEPTED DECLINED TENTATIVE
+	;
+case *
+	echo 'pim/rsvp: want accepted, declined or tentative' >[1=2]
+	exit usage
+}
+pat=$"*
+
+# an occurrence path names one outright; anything else is a search
+occ=()
+if(test -f $"pat)
+	occ=$"pat
+if(~ $#occ 0){
+	hits=`{pim/show -m $mtpt -n $days $only -a $"pat >[2]/dev/null | sed -n 's/^at *//p'}
+	if(~ $#hits 0){
+		echo 'pim/rsvp: nothing matching '^$"pat >[1=2]
+		exit notfound
+	}
+	# A recurring event matches once per occurrence, and the answer
+	# applies to the series, so count distinct events rather than hits.
+	evs=()
+	for(h in $hits){
+		hd=`{basename -d $h}
+		he=`{sed -n 's/^event: //p' $h}
+		if(! ~ $#he 0)
+			evs=($evs `{cleanname $hd/$"he})
+	}
+	evs=`{echo $evs | tr ' ' '\n' | sort -u}
+	if(! ~ $#evs 1){
+		echo 'pim/rsvp: '^$#evs^' events match; be more specific:' >[1=2]
+		for(x in $evs)
+			echo '	'^$x >[1=2]
+		exit ambiguous
+	}
+	occ=$hits(1)
+}
+
+# the occurrence points at its event; 9P has no symlinks, so it is a path
+d=`{basename -d $"occ}
+ev=`{sed -n 's/^event: //p' $"occ}
+if(~ $#ev 0){
+	echo 'pim/rsvp: '^$"occ^' has no event: line' >[1=2]
+	exit noevent
+}
+e=`{cleanname $d/$"ev}
+
+if(! test -f $e/partstat){
+	echo 'pim/rsvp: '^$"e^' has no partstat' >[1=2]
+	exit nopartstat
+}
+
+# Say why before the write fails. A published .ics has nowhere to put a
+# reply and no invitation to reply to, and "permission denied" does not
+# explain that.
+c=`{echo $"e | sed 's|(/.*/calendars/[^/]+)/.*|\1|'}
+caps=`{sed -n 's/^caps //p' $"c/ctl >[2]/dev/null}
+# ~ takes its first argument as the subject, so `~ $caps rsvp` asks
+# whether "read" is "rsvp". Walk the list instead.
+can=()
+for(x in $caps)
+	if(~ $x rsvp)
+		can=1
+if(! ~ $#caps 0)
+	if(~ $#can 0){
+		echo 'pim/rsvp: '^`{basename $"c}^' is '^$"caps^', it cannot answer invitations' >[1=2]
+		exit readonly
+	}
+
+echo $want >$e/partstat
+sum=`{sed -n 's/^summary: //p' $"occ}
+echo $"sum^': '^$want
+exit 0