fix: Read receipts and filtered events

lib/utils/filtered_timeline_extension.dart

@@ -0,0 +1,41 @@
+import 'package:famedlysdk/famedlysdk.dart';
+
+import '../app_config.dart';
+
+extension FilteredTimelineExtension on Timeline {
+  List<Event> getFilteredEvents({bool collapseRoomCreate = true}) {
+    final filteredEvents = events
+        .where((e) =>
+            // always filter out edit and reaction relationships
+            !{RelationshipTypes.Edit, RelationshipTypes.Reaction}
+                .contains(e.relationshipType) &&
+            // always filter out m.key.* events
+            !e.type.startsWith('m.key.verification.') &&
+            // event types to hide: redaction and reaction events
+            // if a reaction has been redacted we also want it to be hidden in the timeline
+            !{EventTypes.Reaction, EventTypes.Redaction}.contains(e.type) &&
+            // if we enabled to hide all redacted events, don't show those
+            (!AppConfig.hideRedactedEvents || !e.redacted) &&
+            // if we enabled to hide all unknown events, don't show those
+            (!AppConfig.hideUnknownEvents || e.isEventTypeKnown) &&
+            // remove state events that we don't want to render
+            (!{EventTypes.Message, EventTypes.Sticker, EventTypes.Encrypted}
+                    .contains(e.type) ||
+                !AppConfig.hideAllStateEvents))
+        .toList();
+
+    // Hide state events from the room creater right after the room created event
+    if (collapseRoomCreate &&
+        filteredEvents[filteredEvents.length - 1].type ==
+            EventTypes.RoomCreate) {
+      while (filteredEvents.length >= 3 &&
+          filteredEvents[filteredEvents.length - 2].senderId ==
+              filteredEvents[filteredEvents.length - 1].senderId &&
+          ![EventTypes.Message, EventTypes.Sticker, EventTypes.Encrypted]
+              .contains(filteredEvents[filteredEvents.length - 2].type)) {
+        filteredEvents.removeAt(filteredEvents.length - 2);
+      }
+    }
+    return filteredEvents;
+  }
+}

lib/utils/room_status_extension.dart

@@ -1,7 +1,7 @@
 import 'package:famedlysdk/famedlysdk.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_gen/gen_l10n/l10n.dart';
-
+import 'filtered_timeline_extension.dart';
 import '../app_config.dart';
 import 'date_time_extension.dart';
 
@@ -61,4 +61,36 @@ extension RoomStatusExtension on Room {
     }
     return typingText;
   }
+
+  String getLocalizedSeenByText(
+      BuildContext context, Timeline timeline, List<Event> filteredEvents) {
+    var seenByText = '';
+    if (timeline.events.isNotEmpty) {
+      final filteredEvents =
+          timeline.getFilteredEvents(collapseRoomCreate: false);
+      final lastReceipts = <User>{};
+      // now we iterate the timeline events until we hit the first rendered event
+      for (final event in timeline.events) {
+        lastReceipts.addAll(event.receipts.map((r) => r.user));
+        if (event.eventId == filteredEvents.first.eventId) {
+          break;
+        }
+      }
+      lastReceipts.removeWhere((user) =>
+          user.id == client.userID || user.id == filteredEvents.first.senderId);
+      if (lastReceipts.length == 1) {
+        seenByText =
+            L10n.of(context).seenByUser(lastReceipts.first.calcDisplayname());
+      } else if (lastReceipts.length == 2) {
+        seenByText = seenByText = L10n.of(context).seenByUserAndUser(
+            lastReceipts.first.calcDisplayname(),
+            lastReceipts.last.calcDisplayname());
+      } else if (lastReceipts.length > 2) {
+        seenByText = L10n.of(context).seenByUserAndCountOthers(
+            lastReceipts.first.calcDisplayname(),
+            (lastReceipts.length - 1).toString());
+      }
+    }
+    return seenByText;
+  }
 }