vCalendar 1.0: fixed recurring all-day event support

vCalendar 1.0 cannot represent all-day events. The workarounds for
mapping iCalendar 2.0 all-day events into vCalendar 1.0 was
incomplete, leading to effects like shifting EXDATEs and end
times. Example below.

The fix involves several changes:
- EXDATE needs the same conversion="autodate" conversion, so that
  date-only values are sent as date-time when converting to vCalendar 1.0
- End date/time (RR_END) must be converted back to date-only, taking
  the local time zone into account to get correct results.
- EXDATE was converted back to date-only, but without the conversion
  to the local time zone. That shifted the exception dates by one day.
- This last conversion was done for recurring events unless they were
  hourly. In other words, it was done also for non-all-day events.
  This happens to work, although opinions vary whether an all-day EXDATE
  really is valid with a non-all-day DTSTART. The comments in
  bugzilla.moblin.org #3009 where this code was introduced mention a
  bug in Evolution/libical around DATE-TIME EXDATE. Whatever that problem
  was, it no longer occurs in Evolution 2.32 with libical from Debian
  Stable. Time to remove this workaround and only apply the conversion
  when really needed (all-day events).

Example before this fix, from testing against Mobical (aka EverDroid),
after adding new test cases:

Client_Sync_eds_event_testItems.A.test.dat | Client_Sync_eds_event_testItems.B.test.dat
                     only in left file <
                                       > only in right file
-------------------------------------------------------------------------------
BEGIN:VCALENDAR                          BEGIN:VCALENDAR
VERSION:2.0                              VERSION:2.0
  BEGIN:VEVENT                             BEGIN:VEVENT
  SUMMARY:all-day recurrence\, daily\      SUMMARY:all-day recurrence\, daily\
   , with exceptions                        , with exceptions
  DESCRIPTION:recurrs seven times\, e      DESCRIPTION:recurrs seven times\, e
   xcluding (but counting) Friday and       xcluding (but counting) Friday and
   Saturday                                 Saturday
  DTEND;VALUE=DATE:20060407            |   DTEND:20060406T215959Z
  DTSTART;VALUE=DATE:20060406          |   DTSTART:20060405T220000Z
                                       >   EXDATE:20060406
  EXDATE:20060407                          EXDATE:20060407
  EXDATE:20060408                      |   RRULE:FREQ=DAILY;UNTIL=20060412T215
  RRULE:FREQ=DAILY;UNTIL=20060412      |    959Z
  END:VEVENT                               END:VEVENT
END:VCALENDAR                            END:VCALENDAR
-------------------------------------------------------------------------------
BEGIN:VCALENDAR                          BEGIN:VCALENDAR
VERSION:2.0                              VERSION:2.0
  BEGIN:VEVENT                             BEGIN:VEVENT
  SUMMARY:recurrence\, daily\, with e      SUMMARY:recurrence\, daily\, with e
   xceptions                                xceptions
  DESCRIPTION:recurrs seven times\, e      DESCRIPTION:recurrs seven times\, e
   xcluding (but counting) Friday and       xcluding (but counting) Friday and
   Saturday                                 Saturday
  DTEND:20060406T190000Z                   DTEND:20060406T190000Z
  DTSTART:20060406T183000Z                 DTSTART:20060406T183000Z
  EXDATE:20060407T183000Z              |   EXDATE:20060407
  EXDATE:20060408T183000Z              |   EXDATE:20060408
  RRULE:FREQ=DAILY;UNTIL=20060412T183      RRULE:FREQ=DAILY;UNTIL=20060412T183
   000Z                                     000Z
  END:VEVENT                               END:VEVENT
END:VCALENDAR                            END:VCALENDAR
-------------------------------------------------------------------------------

2 files changed, 8 insertions, 4 deletions

diff --git a/src/syncevo/configs/datatypes/11calendar-profile.xml b/src/syncevo/configs/datatypes/11calendar-profile.xml
index b4a95f0d..4236bb77 100644
--- a/src/syncevo/configs/datatypes/11calendar-profile.xml
+++ b/src/syncevo/configs/datatypes/11calendar-profile.xml
@@ -390,7 +390,7 @@
           </property>
 
           <property name="EXDATE" values="list" suppressempty="yes" onlyformode="old" delayedparsing="1" valueseparator=";" altvalueseparator=",">
-            <value field="EXDATES"/>
+            <value field="EXDATES" conversion="autodate"/>
             <position field="EXDATES" repeat="array" increment="1" minshow="0"/>
           </property>
 
diff --git a/src/syncevo/configs/scripting/11calendar.xml b/src/syncevo/configs/scripting/11calendar.xml
index c2ea003c..069296e9 100644
--- a/src/syncevo/configs/scripting/11calendar.xml
+++ b/src/syncevo/configs/scripting/11calendar.xml
@@ -24,6 +24,9 @@
           // - convert start to user zone (or floating) so it represents midnight
           DTSTART = CONVERTTOUSERZONE(DTSTART);
           MAKEALLDAY(DTSTART,DTEND,i);
+          if (RR_END != EMPTY) {
+             RR_END = DATEONLY(CONVERTTOUSERZONE(RR_END));
+          }
         }
         else {
           // iCalendar 2.0 - only if DTSTART is a date-only value this really is an allday
@@ -52,14 +55,15 @@
             i=i+1;
           }
         }
-        // If vcalendar1.0, rrule is not secondly, minutely, or hourly, we strip time information
-        // and only reserve date information
-        if (ITEMDATATYPE()=="vCalendar10" && RR_FREQ!="h" && RR_FREQ!="m" && RR_FREQ!="s") {
+        // vCalendar1.0 has no VALUE=DATE EXDATEs, so convert back to that if
+        // the event is all-day.
+        if (ITEMDATATYPE()=="vCalendar10" && ISDATEONLY(DTSTART)) {
           timestamp exdate;
           i = 0;
           while (i<SIZE(EXDATES)) {
             exdate = EXDATES[i];
             if (!ISDATEONLY(exdate)) {
+              exdate = CONVERTTOUSERZONE(exdate);
               EXDATES[i] = DATEONLY(exdate);
             }
             i=i+1;