Added cancel single event of recurring events

app/src/main/java/eu/faircode/email/AdapterMessage.java

@@ -4094,7 +4094,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                                     CalendarHelper.insert(context, icalendar, event,
                                             CalendarContract.Events.STATUS_CONFIRMED, account, message);
                                 else if (action == R.id.btnCalendarDecline)
-                                    CalendarHelper.delete(context, event, message);
+                                    CalendarHelper.delete(context, icalendar, event, account, message);
                                 else if (action == R.id.btnCalendarMaybe)
                                     CalendarHelper.insert(context, icalendar, event,
                                             CalendarContract.Events.STATUS_TENTATIVE, account, message);

app/src/main/java/eu/faircode/email/CalendarHelper.java

@@ -28,6 +28,7 @@ import android.database.Cursor;
 import android.net.Uri;
 import android.provider.CalendarContract;
 import android.text.TextUtils;
+import android.util.Pair;
 
 import androidx.preference.PreferenceManager;
 
@@ -61,6 +62,7 @@ import biweekly.property.Action;
 import biweekly.property.Attendee;
 import biweekly.property.ICalProperty;
 import biweekly.property.RawProperty;
+import biweekly.property.RecurrenceId;
 import biweekly.property.RecurrenceRule;
 import biweekly.property.Trigger;
 import biweekly.util.Duration;
@@ -166,21 +168,22 @@ public class CalendarHelper {
         }
     }
 
-    static Long insert(Context context, ICalendar icalendar, VEvent event, int status,
+    static Pair<String, String> getSelectedCalendar(EntityAccount account) {
-                       EntityAccount account, EntityMessage message) {
-        String selectedAccount;
-        String selectedName;
         try {
             JSONObject jselected = new JSONObject(account.calendar);
-            selectedAccount = jselected.getString("account");
+            return new Pair<>(
-            selectedName = jselected.optString("name", null);
+                    jselected.getString("account"),
+                    jselected.optString("name", null));
         } catch (Throwable ex) {
             Log.i(ex);
-            selectedAccount = account.calendar;
+            return new Pair<>(account.calendar, null);
-            selectedName = null;
         }
+    }
 
-        return insert(context, icalendar, event, status, selectedAccount, selectedName, message);
+    static Long insert(Context context, ICalendar icalendar, VEvent event, int status,
+                       EntityAccount account, EntityMessage message) {
+        Pair<String, String> selected = getSelectedCalendar(account);
+        return insert(context, icalendar, event, status, selected.first, selected.second, message);
     }
 
     static Long insert(Context context, ICalendar icalendar, VEvent event, int status,
@@ -493,11 +496,36 @@ public class CalendarHelper {
         }
     }
 
-    static void delete(Context context, VEvent event, EntityMessage message) {
+    static void delete(Context context, ICalendar icalendar, VEvent event, EntityAccount account, EntityMessage message) {
         String uid = (event.getUid() == null ? null : event.getUid().getValue());
         if (TextUtils.isEmpty(uid))
             return;
 
+        RecurrenceId recurrenceId = event.getProperty(biweekly.property.RecurrenceId.class);
+        if (recurrenceId != null) {
+            ICalDate start = recurrenceId.getValue();
+            if (!start.hasTime())
+                return;
+
+            Pair<String, String> selected = getSelectedCalendar(account);
+            Long existId = exists(context, selected.first, selected.second, uid);
+            if (existId == null)
+                return;
+
+            ContentValues values = new ContentValues();
+            values.put(CalendarContract.Events.ORIGINAL_INSTANCE_TIME, start.getTime());
+            values.put(CalendarContract.Events.EVENT_TIMEZONE, "UTC");
+            values.put(CalendarContract.Events.STATUS, CalendarContract.Events.STATUS_CANCELED);
+            Uri uri = Uri.withAppendedPath(CalendarContract.Events.CONTENT_EXCEPTION_URI,
+                    String.valueOf(existId));
+            ContentResolver resolver = context.getContentResolver();
+            Uri cancel = resolver.insert(uri, values);
+            EntityLog.log(context, EntityLog.Type.General, message, "Inserted recurring event cancel" +
+                    " start=" + new Date(start.getTime()) +
+                    " uri=" + cancel);
+            return;
+        }
+
         ContentResolver resolver = context.getContentResolver();
         try (Cursor cursor = resolver.query(CalendarContract.Events.CONTENT_URI,
                 new String[]{CalendarContract.Events._ID},

app/src/main/java/eu/faircode/email/MessageHelper.java

@@ -4760,7 +4760,7 @@ public class MessageHelper {
                     // https://www.rfc-editor.org/rfc/rfc5546#section-3.2
                     Method method = icalendar.getMethod();
                     if (method != null && method.isCancel())
-                        CalendarHelper.delete(context, event, message);
+                        CalendarHelper.delete(context, icalendar, event, account, message);
                     else if (method == null || method.isRequest()) {
                         if (ical_tentative)
                             CalendarHelper.insert(context, icalendar, event,