ios: optimize performance of updating chats (#4723)

* ios: optimize performance of updating chats

* even simpler

* always use updateChats

* make chats readonly from outside of model

apps/ios/Shared/Model/ChatModel.swift

@@ -143,7 +143,7 @@ final class ChatModel: ObservableObject {
     @Published var contentViewAccessAuthenticated: Bool = false
     @Published var laRequest: LocalAuthRequest?
     // list of chat "previews"
-    @Published var chats: [Chat] = []
+    @Published private(set) var chats: [Chat] = []
     @Published var deletedChats: Set<String> = []
     // current chat
     @Published var chatId: String?
@@ -357,25 +357,8 @@ final class ChatModel: ObservableObject {
         }
     }
 
-    func updateChats(with newChats: [ChatData]) {
-        for i in 0..<newChats.count {
-            let c = newChats[i]
-            if let j = getChatIndex(c.id)   {
-                let chat = chats[j]
-                chat.chatInfo = c.chatInfo
-                chat.chatItems = c.chatItems
-                chat.chatStats = c.chatStats
-                if i != j {
-                    if chatId != c.chatInfo.id  {
-                        popChat_(j, to: i)
-                    }  else if i == 0 {
-                        chatToTop = c.chatInfo.id
-                    }
-                }
-            } else {
-                addChat_(Chat(c), at: i)
-            }
-        }
+    func updateChats(_ newChats: [ChatData]) {
+        chats = newChats.map { Chat($0) }
         NtfManager.shared.setNtfBadgeCount(totalUnreadCountForAllUsers())
         popChatCollector.clear()
     }

apps/ios/Shared/Model/SimpleXAPI.swift

@@ -1591,8 +1591,7 @@ func getUserChatData() throws {
     m.userAddress = try apiGetUserAddress()
     m.chatItemTTL = try getChatItemTTL()
     let chats = try apiGetChats()
-    m.chats = chats.map { Chat.init($0) }
-    m.popChatCollector.clear()
+    m.updateChats(chats)
 }
 
 private func getUserChatDataAsync() async throws {
@@ -1604,14 +1603,12 @@ private func getUserChatDataAsync() async throws {
         await MainActor.run {
             m.userAddress = userAddress
             m.chatItemTTL = chatItemTTL
-            m.chats = chats.map { Chat.init($0) }
-            m.popChatCollector.clear()
+            m.updateChats(chats)
         }
     } else {
         await MainActor.run {
             m.userAddress = nil
-            m.chats = []
-            m.popChatCollector.clear()
+            m.updateChats([])
         }
     }
 }

apps/ios/Shared/SimpleXApp.swift

@@ -133,7 +133,7 @@ struct SimpleXApp: App {
     private func updateChats() {
         do {
             let chats = try apiGetChats()
-            chatModel.updateChats(with: chats)
+            chatModel.updateChats(chats)
             if let id = chatModel.chatId,
                let chat = chatModel.getChat(id) {
                 Task { await loadChat(chat: chat, clearItems: false) }

apps/ios/Shared/Views/ChatList/ChatListView.swift

@@ -501,21 +501,21 @@ func chatStoppedIcon() -> some View {
 struct ChatListView_Previews: PreviewProvider {
     static var previews: some View {
         let chatModel = ChatModel()
-        chatModel.chats = [
-            Chat(
+        chatModel.updateChats([
+            ChatData(
                 chatInfo: ChatInfo.sampleData.direct,
                 chatItems: [ChatItem.getSample(1, .directSnd, .now, "hello")]
             ),
-            Chat(
+            ChatData(
                 chatInfo: ChatInfo.sampleData.group,
                 chatItems: [ChatItem.getSample(1, .directSnd, .now, "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.")]
             ),
-            Chat(
+            ChatData(
                 chatInfo: ChatInfo.sampleData.contactRequest,
                 chatItems: []
             )
 
-        ]
+        ])
         return Group {
             ChatListView(showSettings: Binding.constant(false))
                 .environmentObject(chatModel)

apps/ios/Shared/Views/Database/DatabaseView.swift

@@ -491,7 +491,7 @@ struct DatabaseView: View {
         appFilesCountAndSize = directoryFileCountAndSize(getAppFilesDirectory())
         do {
             let chats = try apiGetChats()
-            m.updateChats(with: chats)
+            m.updateChats(chats)
         } catch let error {
             logger.error("apiGetChats: cannot update chats \(responseError(error))")
         }

apps/ios/Shared/Views/LocalAuth/LocalAuthView.swift

@@ -65,8 +65,7 @@ struct LocalAuthView: View {
                 // Clear sensitive data on screen just in case app fails to hide its views while new database is created
                 m.chatId = nil
                 ItemsModel.shared.reversedChatItems = []
-                m.chats = []
-                m.popChatCollector.clear()
+                m.updateChats([])
                 m.users = []
                 _ = kcAppPassword.set(password)
                 _ = kcSelfDestructPassword.remove()

apps/ios/SimpleXChat/ChatTypes.swift

@@ -1500,6 +1500,12 @@ public struct ChatData: Decodable, Identifiable, Hashable, ChatLike {
 
     public var id: ChatId { get { chatInfo.id } }
 
+    public init(chatInfo: ChatInfo, chatItems: [ChatItem], chatStats: ChatStats = ChatStats()) {
+        self.chatInfo = chatInfo
+        self.chatItems = chatItems
+        self.chatStats = chatStats
+    }
+    
     public static func invalidJSON(_ json: String) -> ChatData {
         ChatData(
             chatInfo: .invalidJSON(json: json),