fix: add main thread receipts to event.receipts getter

lib/src/event.dart

@@ -312,13 +312,27 @@ class Event extends MatrixEvent {
             entry.value.timestamp))
         .toList();
 
-    final own = receipts.global.latestOwnReceipt;
+    // add your own only once
+    final own = receipts.global.latestOwnReceipt ??
+        receipts.mainThread?.latestOwnReceipt;
     if (own != null && own.eventId == eventId) {
-      receiptsList.add(Receipt(
+      receiptsList.add(
-          room.unsafeGetUserFromMemoryOrFallback(room.client.userID!),
+        Receipt(room.unsafeGetUserFromMemoryOrFallback(room.client.userID!),
-          own.timestamp));
+            own.timestamp),
+      );
     }
 
+    // also add main thread. https://github.com/famedly/product-management/issues/1020
+    // also deduplicate.
+    receiptsList.addAll(receipts.mainThread?.otherUsers.entries
+            .where((entry) =>
+                entry.value.eventId == eventId &&
+                receiptsList.every((element) => element.user.id != entry.key))
+            .map((entry) => Receipt(
+                room.unsafeGetUserFromMemoryOrFallback(entry.key),
+                entry.value.timestamp)) ??
+        []);
+
     return receiptsList;
   }
 

test/timeline_test.dart

@@ -375,6 +375,68 @@ void main() {
       expect(room.receiptState.byThread.length, 1);
       expect(timeline.events[1].receipts.length, 2);
       expect(timeline.events[1].receipts[0].user.id, '@bob:example.com');
+
+      // test receipt only on main thread
+      expect(timeline.events[2].receipts.length, 1);
+      await client.handleSync(SyncUpdate(
+          nextBatch: 'something5',
+          rooms: RoomsUpdate(join: {
+            timeline.room.id: JoinedRoomUpdate(ephemeral: [
+              BasicRoomEvent.fromJson({
+                'type': 'm.receipt',
+                'content': {
+                  '\$2': {
+                    'm.read': {
+                      '@eve:example.com': {
+                        'ts': 1436451550453,
+                        'thread_id': 'main'
+                      },
+                      '@john:example.com': {
+                        'ts': 1436451550453,
+                        'thread_id': 'main'
+                      },
+                    },
+                  },
+                },
+              })
+            ])
+          })));
+
+      expect(room.receiptState.global.otherUsers['@eve:example.com']?.eventId,
+          null);
+      expect(
+          room.receiptState.mainThread?.otherUsers['@eve:example.com']?.eventId,
+          '\$2');
+      expect(timeline.events[1].receipts.length, 2);
+      expect(timeline.events[2].receipts.length, 3);
+
+      // test own receipt on main thread
+
+      await client.handleSync(SyncUpdate(
+          nextBatch: 'something6',
+          rooms: RoomsUpdate(join: {
+            timeline.room.id: JoinedRoomUpdate(ephemeral: [
+              BasicRoomEvent.fromJson({
+                'type': 'm.receipt',
+                'content': {
+                  '\$2': {
+                    'm.read': {
+                      client.userID: {
+                        'ts': 1436451550453,
+                        'thread_id': 'main',
+                      },
+                    },
+                  },
+                },
+              })
+            ])
+          })));
+      expect(room.receiptState.global.latestOwnReceipt?.eventId, '\$1');
+      expect(room.receiptState.mainThread?.latestOwnReceipt?.eventId, '\$2');
+      expect(room.receiptState.global.ownPublic?.eventId, '\$2');
+      expect(room.receiptState.mainThread?.ownPublic?.eventId, '\$2');
+      expect(room.receiptState.global.ownPrivate?.eventId, '\$1');
+      expect(timeline.events[2].receipts.length, 3);
     });
 
     test('Sending both receipts at the same time sets the latest receipt',