Add invite.ics attachment (fix #2)

```mail```-Aufruf und Zeitplanung ist nicht getestet

invite.ics

@@ -0,0 +1,30 @@
+BEGIN:VCALENDAR
+PRODID:-//KrautSpace Jena//KrautSpace Einladescript//DE
+VERSION:2.0
+CALSCALE:GREGORIAN
+METHOD:REQUEST
+BEGIN:VEVENT
+DTSTART:#DTSTART#
+DTEND:#DTEND#
+DTSTAMP:#DTSTAMP#
+UID:#DTSTAMP#@kraut.space
+SUMMARY:#SUMMARY#
+DESCRIPTION:Wir treffen uns um 20 Uhr im virtuellen Raum unter:
+ \n\nhttps://blue.kabi.tk/b/hac-nuf-fp4
+ \n\nFür Vorbereitung und Protokoll gibt es wieder ein Pad, 
+ bitte tragt schon mal Themen ein, die Ihr gern besprechen würdet:
+ \n\nhttps://vereinte.verwirrung.institute/p/ksplenum-#URLDATE#
+ \n\n\nGgf. muss das Pad erst noch vorbereitet werden, 
+ die Vorlage mit Anleitung findet Ihr hier: 
+ \n\nhttps://vereinte.verwirrung.institute/p/ksplenum-template
+LOCATION:#LOCATION#
+ORGANIZER;CN=KrautSpace Jena;
+ SENT-BY="MAILTO:#FROM#"
+ :mailto:#REPLY_TO#
+SEQUENCE:0
+STATUS:CONFIRMED
+CLASS:PUBLIC
+CATEGORIES:MEETING
+TRANSP:OPAQUE
+END:VEVENT
+END:VCALENDAR

invite.sh

@@ -4,18 +4,17 @@
 
 from="office@krautspace.de"
 to=("hackspace-jena@lstsrv.org" "krautspace-announce@lstsrv.org")
+replyto="hackspace-jena@lstsrv.org"
 subject="Einladung zum Plenum"
+location_url="https://blue.kabi.tk/b/hac-nuf-fp4"
 body_file=email_text # Use PROSEDATE for dd.mm.YYYY and URLDATE for YYYmmdd
 
 ## Find next Thursday
-
-day_of_week=$(date +%u)
-
-next_thursday_offset=$(( ( ( 7 - $day_of_week ) + 4 ) % 7 ))
+date_fmt () { date -u -d "$2 next Thu" $1; }
 
 ## Check if next Thursday is the first of a month
 
-if (( $(date -d "+$next_thursday_offset days" +%_d) > 7 )); then
+if (( $(date_fmt +%_d) > 7 )); then
     echo "Invitation should be sent at most a week in advance."
     echo "Exiting without sending an inviation..."
     exit
@@ -23,10 +22,25 @@ fi
 
 ## Send invitation
 
-prose_date=$(date -d "+$next_thursday_offset days" +%d.%m.%Y)
-url_date=$(date -d "+$next_thursday_offset days" +%Y%m%d)
+prose_date=$(date_fmt +%d.%m.%Y)
+url_date=$(date_fmt +%Y%m%d)
 
 script_path=$(readlink -f "$0")
 source_directory=$(dirname "$script_path")
 
-cat "$source_directory/$body_file" | sed -e "s/PROSEDATE/$prose_date/g" | sed -e "s/URLDATE/$url_date/g" | mail -s "$subject" -r "$from" "${to[@]}"
+sed -e "s/#DTSTART#/$(date_fmt +%Y%m%dT%H%M%SZ "TZ=\"Europe/Berlin\" 20:00")/" \
+	-e "s/#DTEND#/$(date_fmt +%Y%m%dT%H%M%SZ "TZ=\"Europe/Berlin\" 21:00")/" \
+	-e "s/#DTSTAMP#/$(date -u +%Y%m%dT%H%M%SZ)/" \
+	-e "s/#SUMMARY#/KrautSpace Plenum/" \
+	-e "s/#LOCATION#/${location}/" \
+	-e "s/#FROM#/${from}/g" \
+	-e "s/#REPLY_TO#/${replyto}/g" \
+	-e "s/#URLDATE#/${url_date}/g" \
+	invite.ics > /tmp/invite.ics
+
+sed -e "s/PROSEDATE/$prose_date/g" \
+	-e "s/URLDATE/$url_date/g" \
+	"$source_directory/$body_file" | mail -s "$subject" -r "$from" -a /tmp/invite.ics "${to[@]}"
+ret=$?
+rm -f /tmp/invite.ics
+exit $ret

plenums_invite.service

@@ -4,3 +4,5 @@ Description=Send invitation to Hackspace's Plenum
 [Service]
 Type=oneshot
 ExecStart=/opt/plenums_invite/invite.sh
+
+PrivateTmp=yes