a bunch more usability improvements

Signed-off-by: William Casarin <jb55@jb55.com>

damus/ContentView.swift

@@ -213,7 +213,6 @@ struct ContentView: View {
             self.pool?.send(.event(ev))
         }
         .onReceive(NotificationCenter.default.publisher(for: .post)) { obj in
-
             let post_res = obj.object as! NostrPostResult
             switch post_res {
             case .post(let post):
@@ -256,13 +255,19 @@ struct ContentView: View {
     }
 
     func switch_timeline(_ timeline: Timeline) {
-        if timeline != .notifications {
+        if timeline == self.selected_timeline {
+            NotificationCenter.default.post(name: .scroll_to_top, object: nil)
+            return
+        }
+        
+        if (timeline != .notifications && self.selected_timeline == .notifications) || timeline == .notifications {
             new_notifications = false
         }
         self.selected_timeline = timeline
+        NotificationCenter.default.post(name: .switched_timeline, object: timeline)
         //self.selected_timeline = timeline
     }
-
+    
     func add_relay(_ pool: RelayPool, _ relay: String) {
         //add_rw_relay(pool, "wss://nostr-pub.wellorder.net")
         add_rw_relay(pool, relay)

damus/Models/ThreadModel.swift

@@ -36,11 +36,35 @@ class ThreadModel: ObservableObject {
         self.replies.replies.removeAll()
     }
     
+    func should_resubscribe(_ ev_b: NostrEvent) -> Bool {
+        if self.events.count == 0 {
+            return true
+        }
+        
+        guard let ev_a = self.event else {
+            return true
+        }
+        
+        if ev_b.is_root_event() {
+            return false
+        }
+
+        // rough heuristic to save us from resubscribing all the time
+        return ev_b.count_ids() != ev_a.count_ids()
+    }
+    
     func set_active_event(_ ev: NostrEvent) {
-        unsubscribe()
-        self.event = ev
-        add_event(ev)
-        subscribe(ev)
+        if should_resubscribe(ev) {
+            unsubscribe()
+            self.event = ev
+            add_event(ev)
+            subscribe(ev)
+        } else {
+            self.event = ev
+            if events.count == 0 {
+                add_event(ev)
+            }
+        }
     }
     
     private func subscribe(_ ev: NostrEvent) {

damus/Nostr/NostrEvent.swift

@@ -179,6 +179,20 @@ class NostrEvent: Codable, Identifiable, CustomStringConvertible {
         return (ns, c)
     }
     
+    public func count_ids() -> Int {
+        return count_refs("e")
+    }
+    
+    public func count_refs(_ type: String) -> Int {
+        var count: Int = 0
+        for tag in tags {
+            if tag.count >= 2 && tag[0] == "e" {
+                count += 1
+            }
+        }
+        return count
+    }
+    
     public var referenced_pubkeys: [ReferencedId] {
         return get_referenced_ids(key: "p")
     }

damus/Notifications.swift

@@ -25,6 +25,18 @@ extension Notification.Name {
     }
 }
 
+extension Notification.Name {
+    static var switched_timeline: Notification.Name {
+        return Notification.Name("switched_timeline")
+    }
+}
+
+extension Notification.Name {
+    static var scroll_to_top: Notification.Name {
+        return Notification.Name("scroll_to_to")
+    }
+}
+
 extension Notification.Name {
     static var broadcast_event: Notification.Name {
         return Notification.Name("broadcast event")

damus/Views/ChatView.swift

@@ -148,7 +148,7 @@ struct ChatView: View {
         .contentShape(Rectangle())
         .id(event.id)
         .frame(minHeight: just_started ? PFP_SIZE : 0)
-        //.padding([.bottom], next_ev == nil ? 2 : 0)
+        .padding([.bottom], next_ev == nil ? 30 : 0)
         //.border(Color.green)
         
     }

damus/Views/ThreadView.swift

@@ -13,6 +13,7 @@ struct ThreadView: View {
     
     @EnvironmentObject var profiles: Profiles
     @EnvironmentObject var thread: ThreadModel
+    @Environment(\.dismiss) var dismiss
     
     var body: some View {
         Group {
@@ -35,6 +36,9 @@ struct ThreadView: View {
             }
              */
         }
+        .onReceive(NotificationCenter.default.publisher(for: .switched_timeline)) { n in
+            dismiss()
+        }
         .onReceive(NotificationCenter.default.publisher(for: .toggle_thread_view)) { _ in
             is_chatroom = !is_chatroom
             //print("is_chatroom: \(is_chatroom)")

damus/Views/TimelineView.swift

@@ -26,22 +26,30 @@ struct TimelineView: View {
     }
     
     var MainContent: some View {
-        ScrollView {
-            LazyVStack {
-                ForEach(events, id: \.id) { (ev: NostrEvent) in
-                    /*
-                    let evdet = EventDetailView(thread: ThreadModel(event: ev, pool: pool))
-                        .navigationBarTitle("Thread")
-                        .padding([.leading, .trailing], 6)
-                        .environmentObject(profiles)
-                     */
-                    
-                    EventView(event: ev, highlight: .none, has_action_bar: true)
-                        .onTapGesture {
-                            NotificationCenter.default.post(name: .open_thread, object: ev)
-                        }
+        ScrollViewReader { scroller in
+            ScrollView {
+                LazyVStack {
+                    ForEach(events, id: \.id) { (ev: NostrEvent) in
+                        /*
+                        let evdet = EventDetailView(thread: ThreadModel(event: ev, pool: pool))
+                            .navigationBarTitle("Thread")
+                            .padding([.leading, .trailing], 6)
+                            .environmentObject(profiles)
+                         */
+                        
+                        EventView(event: ev, highlight: .none, has_action_bar: true)
+                            .onTapGesture {
+                                NotificationCenter.default.post(name: .open_thread, object: ev)
+                            }
+                    }
                 }
             }
+            .onReceive(NotificationCenter.default.publisher(for: .scroll_to_top)) { _ in
+                guard let event = events.first else {
+                    return
+                }
+                scroll_to_event(scroller: scroller, id: event.id, delay: 0.0, animate: true)
+            }
         }
     }
 }