Hide future notes from timeline

Changelog-Fixed: Hide future notes from timeline

Closes: https://github.com/damus-io/damus/issues/2949
Signed-off-by: Terry Yiu <git@tyiu.xyz>

damus/Models/ContentFilters.swift

@@ -40,6 +40,12 @@ func get_repost_of_muted_user_filter(damus_state: DamusState) -> ((_ ev: NostrEv
     }
 }
 
+func timestamp_filter(ev: NostrEvent) -> Bool {
+    // Allow notes that are created no more than 3 seconds in the future
+    // to account for natural clock skew between sender and receiver.
+    ev.age >= -3
+}
+
 /// Generic filter with various tweakable settings
 struct ContentFilters {
     var filters: [(NostrEvent) -> Bool]
@@ -66,6 +72,7 @@ extension ContentFilters {
             filters.append(nsfw_tag_filter)
         }
         filters.append(get_repost_of_muted_user_filter(damus_state: damus_state))
+        filters.append(timestamp_filter)
         return filters
     }
 }

damus/Models/NotificationsManager.swift

@@ -54,7 +54,14 @@ func should_display_notification(state: HeadlessDamusState, event ev: NostrEvent
     guard ev.age < EVENT_MAX_AGE_FOR_NOTIFICATION else {
         return false
     }
-    
+
+    // Don't show notifications for future events.
+    // Allow notes that are created no more than 3 seconds in the future
+    // to account for natural clock skew between sender and receiver.
+    guard ev.age >= -3 else {
+        return false
+    }
+
     return true
 }
 

damus/Views/Notifications/NotificationsView.swift

@@ -41,7 +41,10 @@ class NotificationFilter: ObservableObject, Equatable {
 
             if let item = item.filter({ ev in
                 self.friend_filter.filter(contacts: contacts, pubkey: ev.pubkey) &&
-                (!hellthread_notifications_disabled || !ev.is_hellthread(max_pubkeys: hellthread_notification_max_pubkeys))
+                (!hellthread_notifications_disabled || !ev.is_hellthread(max_pubkeys: hellthread_notification_max_pubkeys)) &&
+                // Allow notes that are created no more than 3 seconds in the future
+                // to account for natural clock skew between sender and receiver.
+                ev.age >= -3
             }) {
                 acc.append(item)
             }