Refactor notifications (#2688)

This PR changes the handling of notifications
- removes the `StreamEvent` and `ReadUpdate` stream
- listens on the `OutputRoomEvent` stream in the UserAPI to inform the
SyncAPI about unread notifications
- listens on the `OutputReceiptEvent` stream in the UserAPI to set
receipts/update notifications
- sets the `read_markers` directly from within the internal UserAPI

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

syncapi/streams/stream_notificationdata.go

@@ -30,26 +30,29 @@ func (p *NotificationDataStreamProvider) CompleteSync(
 func (p *NotificationDataStreamProvider) IncrementalSync(
 	ctx context.Context,
 	req *types.SyncRequest,
-	from, to types.StreamPosition,
+	from, _ types.StreamPosition,
 ) types.StreamPosition {
-	// We want counts for all possible rooms, so always start from zero.
-	countsByRoom, err := p.DB.GetUserUnreadNotificationCounts(ctx, req.Device.UserID, from, to)
+	// Get the unread notifications for rooms in our join response.
+	// This is to ensure clients always have an unread notification section
+	// and can display the correct numbers.
+	countsByRoom, err := p.DB.GetUserUnreadNotificationCountsForRooms(ctx, req.Device.UserID, req.Rooms)
 	if err != nil {
-		req.Log.WithError(err).Error("GetUserUnreadNotificationCounts failed")
+		req.Log.WithError(err).Error("GetUserUnreadNotificationCountsForRooms failed")
 		return from
 	}
 
-	// We're merely decorating existing rooms. Note that the Join map
-	// values are not pointers.
+	// We're merely decorating existing rooms.
 	for roomID, jr := range req.Response.Rooms.Join {
 		counts := countsByRoom[roomID]
 		if counts == nil {
 			continue
 		}
-
-		jr.UnreadNotifications.HighlightCount = counts.UnreadHighlightCount
-		jr.UnreadNotifications.NotificationCount = counts.UnreadNotificationCount
+		jr.UnreadNotifications = &types.UnreadNotifications{
+			HighlightCount:    counts.UnreadHighlightCount,
+			NotificationCount: counts.UnreadNotificationCount,
+		}
 		req.Response.Rooms.Join[roomID] = jr
 	}
-	return to
+
+	return p.LatestPosition(ctx)
 }