Properly handle Update the selected occurrence only

Previously, if an event was modified using some other client then the exception event's parent id was ignored or overwritten with 0 at sync and that means the parent and child events were disconnected locally. Deleting the parent event did not delete the child event.

If a recurrence was modified using Simple Calendar then it was disconnected from it's parent event both locally and on the server because `ORIGINAL_ID` and `ORIGINAL_INSTANCE_TIME` was not specified. On top of that, another exception event was created to make sure the parent event doesn't show up on the date of the disconnected child event.

This change fixes these two issues.

app/src/main/kotlin/com/simplemobiletools/calendar/pro/activities/EventActivity.kt

@@ -1155,7 +1155,7 @@ class EventActivity : SimpleActivity() {
         DeleteEventDialog(this, arrayListOf(mEvent.id!!), mEvent.repeatInterval > 0) {
             ensureBackgroundThread {
                 when (it) {
-                    DELETE_SELECTED_OCCURRENCE -> eventsHelper.addEventRepetitionException(mEvent.id!!, mEventOccurrenceTS, true)
+                    DELETE_SELECTED_OCCURRENCE -> eventsHelper.deleteRepeatingEventOccurrence(mEvent.id!!, mEventOccurrenceTS, true)
                     DELETE_FUTURE_OCCURRENCES -> eventsHelper.addEventRepeatLimit(mEvent.id!!, mEventOccurrenceTS)
                     DELETE_ALL_OCCURRENCES -> eventsHelper.deleteEvent(mEvent.id!!, true)
                 }
@@ -1361,7 +1361,6 @@ class EventActivity : SimpleActivity() {
             when (it) {
                 EDIT_SELECTED_OCCURRENCE -> {
                     ensureBackgroundThread {
-                        eventsHelper.addEventRepetitionException(mEvent.id!!, mEventOccurrenceTS, true)
                         mEvent.apply {
                             parentId = id!!.toLong()
                             id = null
@@ -1370,7 +1369,7 @@ class EventActivity : SimpleActivity() {
                             repeatLimit = 0
                         }
 
-                        eventsHelper.insertEvent(mEvent, true, true) {
+                        eventsHelper.insertEvent(mEvent, addToCalDAV = true, showToasts = true) {
                             finish()
                         }
                     }

app/src/main/kotlin/com/simplemobiletools/calendar/pro/activities/TaskActivity.kt

@@ -474,7 +474,6 @@ class TaskActivity : SimpleActivity() {
             when (it) {
                 EDIT_SELECTED_OCCURRENCE -> {
                     ensureBackgroundThread {
-                        eventsHelper.addEventRepetitionException(mTask.id!!, mTaskOccurrenceTS, addToCalDAV = false)
                         mTask.apply {
                             parentId = id!!.toLong()
                             id = null
@@ -533,9 +532,9 @@ class TaskActivity : SimpleActivity() {
         DeleteEventDialog(this, arrayListOf(mTask.id!!), mTask.repeatInterval > 0, isTask = true) {
             ensureBackgroundThread {
                 when (it) {
-                    DELETE_SELECTED_OCCURRENCE -> eventsHelper.addEventRepetitionException(mTask.id!!, mTaskOccurrenceTS, true)
+                    DELETE_SELECTED_OCCURRENCE -> eventsHelper.deleteRepeatingEventOccurrence(mTask.id!!, mTaskOccurrenceTS, false)
                     DELETE_FUTURE_OCCURRENCES -> eventsHelper.addEventRepeatLimit(mTask.id!!, mTaskOccurrenceTS)
-                    DELETE_ALL_OCCURRENCES -> eventsHelper.deleteEvent(mTask.id!!, true)
+                    DELETE_ALL_OCCURRENCES -> eventsHelper.deleteEvent(mTask.id!!, false)
                 }
 
                 runOnUiThread {

app/src/main/kotlin/com/simplemobiletools/calendar/pro/extensions/Context.kt

@@ -696,7 +696,7 @@ fun Context.handleEventDeleting(eventIds: List<Long>, timestamps: List<Long>, ac
     when (action) {
         DELETE_SELECTED_OCCURRENCE -> {
             eventIds.forEachIndexed { index, value ->
-                eventsHelper.addEventRepetitionException(value, timestamps[index], true)
+                eventsHelper.deleteRepeatingEventOccurrence(value, timestamps[index], true)
             }
         }
         DELETE_FUTURE_OCCURRENCES -> {

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/CalDAVHelper.kt

@@ -185,6 +185,7 @@ class CalDAVHelper(val context: Context) {
             Events.CALENDAR_TIME_ZONE,
             Events.DELETED,
             Events.AVAILABILITY,
+            Events.STATUS,
             Events.EVENT_COLOR
         )
 
@@ -214,6 +215,7 @@ class CalDAVHelper(val context: Context) {
             val reminders = getCalDAVEventReminders(id)
             val attendees = Gson().toJson(getCalDAVEventAttendees(id))
             val availability = cursor.getIntValue(Events.AVAILABILITY)
+            val status = cursor.getIntValue(Events.STATUS)
             val color = cursor.getIntValueOrNull(Events.EVENT_COLOR)
             val displayColor = if (color != null) {
                 getDisplayColorFromColor(color)
@@ -255,14 +257,22 @@ class CalDAVHelper(val context: Context) {
                 val parentImportId = "$source-$originalId"
                 val parentEvent = context.eventsDB.getEventWithImportId(parentImportId)
                 val originalDayCode = Formatter.getDayCodeFromTS(originalInstanceTime / 1000L)
-                if (parentEvent != null && !parentEvent.repetitionExceptions.contains(originalDayCode)) {
+                if (parentEvent != null) {
-                    val storedEventId = context.eventsDB.getEventIdWithImportId(importId)
+                    // add this event to the parent event's list of exceptions
-                    if (storedEventId != null) {
+                    if (!parentEvent.repetitionExceptions.contains(originalDayCode)) {
-                        event.id = storedEventId
+                        parentEvent.addRepetitionException(originalDayCode)
+                        eventsHelper.insertEvent(parentEvent, addToCalDAV = false, showToasts = false)
+                    }
+
+                    // store the event in the local db only if it is an occurrence that has been modified and not deleted
+                    if (status != Events.STATUS_CANCELED) {
+                        val storedEventId = context.eventsDB.getEventIdWithImportId(importId)
+                        if (storedEventId != null) {
+                            event.id = storedEventId
+                        }
+                        event.parentId = parentEvent.id!!
+                        eventsHelper.insertEvent(event, addToCalDAV = false, showToasts = false)
                     }
-                    event.parentId = parentEvent.id!!
-                    parentEvent.addRepetitionException(originalDayCode)
-                    eventsHelper.insertEvent(parentEvent, addToCalDAV = false, showToasts = false)
 
                     return@queryCursorInlined
                 }
@@ -432,6 +442,18 @@ class CalDAVHelper(val context: Context) {
                 put(Events.ALL_DAY, 0)
             }
 
+            val parentEventId = event.parentId
+            if (parentEventId != 0L) {
+                val parentEvent = context.eventsDB.getEventWithId(parentEventId) ?: return@apply
+                put(Events.ORIGINAL_ID, parentEvent.getCalDAVEventId())
+                put(Events.ORIGINAL_INSTANCE_TIME, event.startTS * 1000L)
+                if (parentEvent.getIsAllDay()) {
+                    put(Events.ORIGINAL_ALL_DAY, 1)
+                } else {
+                    put(Events.ORIGINAL_ALL_DAY, 0)
+                }
+            }
+
             put(Events.DTSTART, event.startTS * 1000L)
             put(Events.EVENT_TIMEZONE, event.getTimeZoneString())
             if (event.repeatInterval > 0) {

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/EventsHelper.kt

@@ -116,6 +116,14 @@ class EventsHelper(val context: Context) {
             return
         }
 
+        val parentEventId = event.parentId
+        if (parentEventId != 0L) {
+            val parentEvent = eventsDB.getEventOrTaskWithId(parentEventId) ?: return
+            val startDayCode = Formatter.getDayCodeFromTS(event.startTS)
+            parentEvent.addRepetitionException(startDayCode)
+            eventsDB.updateEventRepetitionExceptions(parentEvent.repetitionExceptions.toString(), parentEventId)
+        }
+
         event.id = eventsDB.insertOrUpdate(event)
 
         context.updateWidgets()
@@ -129,6 +137,14 @@ class EventsHelper(val context: Context) {
     }
 
     fun insertTask(task: Event, showToasts: Boolean, callback: () -> Unit) {
+        val parentEventId = task.parentId
+        if (parentEventId != 0L) {
+            val parentEvent = eventsDB.getEventOrTaskWithId(parentEventId) ?: return
+            val startDayCode = Formatter.getDayCodeFromTS(task.startTS)
+            parentEvent.addRepetitionException(startDayCode)
+            eventsDB.updateEventRepetitionExceptions(parentEvent.repetitionExceptions.toString(), parentEventId)
+        }
+
         task.id = eventsDB.insertOrUpdate(task)
         context.updateWidgets()
         context.scheduleNextEventReminder(task, showToasts)
@@ -232,7 +248,7 @@ class EventsHelper(val context: Context) {
         }
     }
 
-    fun addEventRepetitionException(parentEventId: Long, occurrenceTS: Long, addToCalDAV: Boolean) {
+    fun deleteRepeatingEventOccurrence(parentEventId: Long, occurrenceTS: Long, addToCalDAV: Boolean) {
         ensureBackgroundThread {
             val parentEvent = eventsDB.getEventOrTaskWithId(parentEventId) ?: return@ensureBackgroundThread
             var repetitionExceptions = parentEvent.repetitionExceptions