fixup! fix: getSeenByUsers method to return exact receipts count

lib/utils/room_status_extension.dart

@@ -1,3 +1,4 @@
+import 'package:fluffychat/utils/string_extension.dart';
 import 'package:flutter/widgets.dart';
 
 import 'package:flutter_gen/gen_l10n/l10n.dart';
@@ -92,10 +93,14 @@ extension RoomStatusExtension on Room {
 
     final lastReceipts = <User>{};
 
-    // mainThread.others only contains the last event of the room sent by the current user
     if (receiptState.mainThread != null) {
+      // receiptState contains all users and their last seen event
+      // we checked users that have seen the eventId argument or older
       final mainThreadReceipts = receiptState.mainThread!.otherUsers.entries
-          .where((element) => element.value.eventId == eventId)
+          .where(
+            (element) => element.value.eventId
+                .isEventIdOlderOrSameAs(timeline, eventId!),
+          )
           .map((e) => unsafeGetUserFromMemoryOrFallback(e.key))
           .toList();
       lastReceipts.addAll(mainThreadReceipts);

lib/utils/string_extension.dart

@@ -1,4 +1,5 @@
 import 'package:any_link_preview/any_link_preview.dart';
+import 'package:collection/collection.dart';
 import 'package:fluffychat/widgets/matrix.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/l10n.dart';
@@ -130,4 +131,19 @@ extension StringCasingExtension on String {
 
     return unMarkdownedText;
   }
+
+  bool isEventIdOlderOrSameAs(Timeline timeline, String eventId) {
+    if (timeline.events.isEmpty) return false;
+
+    final firstEvent =
+        timeline.events.firstWhereOrNull((e) => e.eventId == this);
+    final secondEvent =
+        timeline.events.firstWhereOrNull((e) => e.eventId == eventId);
+
+    if (secondEvent == null || firstEvent == null) return false;
+
+    return this == eventId ||
+        timeline.events.indexOf(secondEvent) >
+            timeline.events.indexOf(firstEvent);
+  }
 }