properly import all-day events from nextcloud type services

app/src/main/kotlin/com/simplemobiletools/calendar/helpers/CalDAVHandler.kt

@@ -259,6 +259,8 @@ class CalDAVHandler(val context: Context) {
                             importId, allDay, repeatRule.repeatLimit, repeatRule.repeatRule, eventTypeId, source = source, location = location)
 
                     if (event.getIsAllDay() && endTS > startTS) {
+                        event.startTS = Formatter.getShiftedImportTimestamp(event.startTS)
+                        event.endTS = Formatter.getShiftedImportTimestamp(event.endTS)
                         event.endTS -= DAY
                     }
 

app/src/main/kotlin/com/simplemobiletools/calendar/helpers/Formatter.kt

@@ -99,4 +99,6 @@ object Formatter {
         else
             "0"
     }
+
+    fun getShiftedImportTimestamp(ts: Int) = getDateTimeFromTS(ts).toDateTime(DateTimeZone.UTC).withZoneRetainFields(DateTimeZone.getDefault()).withTime(5, 0, 0, 0).seconds()
 }