HH-569: guard replayed frontend realtime messages (#144)

* fix(HH-569): guard replayed realtime messages

* fix(HH-569): gate dashboard message side effects

---------

Co-authored-by: Rogee <rogee@ipao.vip>

frontend/app/javascript/widget/store/modules/conversation/actions.js

@@ -173,13 +173,24 @@ export const actions = {
     commit('clearConversations');
   },
 
-  addOrUpdateMessage: async ({ commit }, data) => {
+  addOrUpdateMessage: async ({ commit, state }, data) => {
     const { id, content_attributes } = data;
+    const currentMessage = state?.conversations?.[id];
+    const isNew = !currentMessage;
+    if (
+      currentMessage?.updated_at &&
+      data.updated_at &&
+      data.updated_at <= currentMessage.updated_at
+    ) {
+      return { applied: false, isNew };
+    }
+
     if (content_attributes && content_attributes.deleted) {
       commit('deleteMessage', id);
-      return;
+      return { applied: true, isNew };
     }
     commit('pushMessageToConversation', data);
+    return { applied: true, isNew };
   },
 
   toggleAgentTyping({ commit }, data) {

frontend/app/javascript/widget/store/modules/specs/conversation/actions.spec.js

@@ -82,6 +82,38 @@ describe('#actions', () => {
         message_type: 1,
       });
     });
+
+    it('ignores an older realtime update', async () => {
+      const data = {
+        id: 1,
+        updated_at: '2026-08-24T01:00:00Z',
+        content_attributes: {},
+      };
+      const state = {
+        conversations: {
+          1: { id: 1, updated_at: '2026-08-24T02:00:00Z' },
+        },
+      };
+
+      const result = await actions.addOrUpdateMessage({ commit, state }, data);
+
+      expect(result).toEqual({ applied: false, isNew: false });
+      expect(commit).not.toHaveBeenCalled();
+    });
+
+    it('ignores a replayed message with the same id and version', async () => {
+      const data = {
+        id: 1,
+        updated_at: '2026-08-24T02:00:00Z',
+        content_attributes: {},
+      };
+      const state = { conversations: { 1: data } };
+
+      const result = await actions.addOrUpdateMessage({ commit, state }, data);
+
+      expect(result).toEqual({ applied: false, isNew: false });
+      expect(commit).not.toHaveBeenCalled();
+    });
   });
 
   describe('#toggleAgentTyping', () => {