From e6ba82c8ff91164330dc962d93cc916517a4c29b Mon Sep 17 00:00:00 2001
From: Arturs Krumins <auth@levitatingpineapple.com>
Date: Tue, 6 Aug 2024 01:36:33 +0300
Subject: [PATCH] ios: improve performance, when receiving many messages in a
 single chat (#4586)

* use UnreadCollector for new messages

* less confusing

* collect removed items to reduce unread counts

---------

Co-authored-by: Evgeny Poberezkin <evgeny@poberezkin.com>
---
 apps/ios/Shared/Model/ChatModel.swift  | 29 +++++++++++++-------------
 apps/ios/Shared/Model/NtfManager.swift |  8 ++-----
 2 files changed, 16 insertions(+), 21 deletions(-)

diff --git a/apps/ios/Shared/Model/ChatModel.swift b/apps/ios/Shared/Model/ChatModel.swift
index d973ada34e..2e79c7b8ed 100644
--- a/apps/ios/Shared/Model/ChatModel.swift
+++ b/apps/ios/Shared/Model/ChatModel.swift
@@ -333,8 +333,7 @@ final class ChatModel: ObservableObject {
                 [cItem]
             }
             if case .rcvNew = cItem.meta.itemStatus {
-                chats[i].chatStats.unreadCount = chats[i].chatStats.unreadCount + 1
-                increaseUnreadCounter(user: currentUser!)
+                unreadCollector.changeUnreadCounter(cInfo.id, by: 1)
             }
             popChatCollector.addChat(cInfo.id)
         } else {
@@ -414,8 +413,8 @@ final class ChatModel: ObservableObject {
     }
 
     func removeChatItem(_ cInfo: ChatInfo, _ cItem: ChatItem) {
-        if cItem.isRcvNew, let chatIndex = getChatIndex(cInfo.id) {
-            decreaseUnreadCounter(chatIndex)
+        if cItem.isRcvNew {
+            unreadCollector.changeUnreadCounter(cInfo.id, by: -1)
         }
         // update previews
         if let chat = getChat(cInfo.id) {
@@ -570,7 +569,7 @@ final class ChatModel: ObservableObject {
                     // update current chat
                     markChatItemRead_(itemIndex)
                     // update preview
-                    unreadCollector.decreaseUnreadCounter(cInfo.id)
+                    unreadCollector.changeUnreadCounter(cInfo.id, by: -1)
                 }
             }
         }
@@ -590,17 +589,18 @@ final class ChatModel: ObservableObject {
                     let m = ChatModel.shared
                     for (chatId, count) in self.unreadCounts {
                         if let i = m.getChatIndex(chatId) {
-                            m.decreaseUnreadCounter(i, by: count)
+                            m.changeUnreadCounter(i, by: count)
                         }
                     }
                     self.unreadCounts = [:]
                 }
                 .store(in: &bag)
         }
-        
-        // Only call from main thread
-        func decreaseUnreadCounter(_ chatId: ChatId) {
-            unreadCounts[chatId] = (unreadCounts[chatId] ?? 0) + 1
+
+        func changeUnreadCounter(_ chatId: ChatId, by count: Int) {
+            DispatchQueue.main.async {
+                self.unreadCounts[chatId] = (self.unreadCounts[chatId] ?? 0) + count
+            }
             subject.send()
         }
     }
@@ -646,25 +646,24 @@ final class ChatModel: ObservableObject {
         }
     }
 
-    func decreaseUnreadCounter(_ chatIndex: Int, by count: Int = 1) {
-        chats[chatIndex].chatStats.unreadCount = chats[chatIndex].chatStats.unreadCount - count
-        decreaseUnreadCounter(user: currentUser!, by: count)
+    func changeUnreadCounter(_ chatIndex: Int, by count: Int) {
+        chats[chatIndex].chatStats.unreadCount = chats[chatIndex].chatStats.unreadCount + count
+        changeUnreadCounter(user: currentUser!, by: count)
     }
 
     func increaseUnreadCounter(user: any UserLike) {
         changeUnreadCounter(user: user, by: 1)
-        NtfManager.shared.incNtfBadgeCount()
     }
 
     func decreaseUnreadCounter(user: any UserLike, by: Int = 1) {
         changeUnreadCounter(user: user, by: -by)
-        NtfManager.shared.decNtfBadgeCount(by: by)
     }
 
     private func changeUnreadCounter(user: any UserLike, by: Int) {
         if let i = users.firstIndex(where: { $0.user.userId == user.userId }) {
             users[i].unreadCount += by
         }
+        NtfManager.shared.changeNtfBadgeCount(by: by)
     }
 
     func totalUnreadCountForAllUsers() -> Int {
diff --git a/apps/ios/Shared/Model/NtfManager.swift b/apps/ios/Shared/Model/NtfManager.swift
index f1fdcc018e..bb938cd231 100644
--- a/apps/ios/Shared/Model/NtfManager.swift
+++ b/apps/ios/Shared/Model/NtfManager.swift
@@ -238,12 +238,8 @@ class NtfManager: NSObject, UNUserNotificationCenterDelegate, ObservableObject {
         ntfBadgeCountGroupDefault.set(count)
     }
 
-    func decNtfBadgeCount(by count: Int = 1) {
-        setNtfBadgeCount(max(0, UIApplication.shared.applicationIconBadgeNumber - count))
-    }
-
-    func incNtfBadgeCount(by count: Int = 1) {
-        setNtfBadgeCount(UIApplication.shared.applicationIconBadgeNumber + count)
+    func changeNtfBadgeCount(by count: Int = 1) {
+        setNtfBadgeCount(max(0, UIApplication.shared.applicationIconBadgeNumber + count))
     }
 
     private func addNotification(_ content: UNMutableNotificationContent) {