From 1e8d9fd6b2dce311e40457623436196fd99a1032 Mon Sep 17 00:00:00 2001
From: Stefan Ceriu <stefanc@matrix.org>
Date: Wed, 22 Feb 2023 17:58:06 +0200
Subject: [PATCH] Fix visible room sliding sync view ranges changing while
 inside rooms

---
 .../HomeScreen/HomeScreenViewModel.swift      |  9 +-------
 .../Screens/HomeScreen/View/HomeScreen.swift  | 21 +++++++++++++++++--
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/ElementX/Sources/Screens/HomeScreen/HomeScreenViewModel.swift b/ElementX/Sources/Screens/HomeScreen/HomeScreenViewModel.swift
index 1b181f0c7..0f2289e94 100644
--- a/ElementX/Sources/Screens/HomeScreen/HomeScreenViewModel.swift
+++ b/ElementX/Sources/Screens/HomeScreen/HomeScreenViewModel.swift
@@ -20,10 +20,6 @@ import SwiftUI
 typealias HomeScreenViewModelType = StateStoreViewModel<HomeScreenViewState, HomeScreenViewAction>
 
 class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol {
-    enum Constants {
-        static let slidingWindowBoundsPadding = 5
-    }
-    
     private let userSession: UserSessionProtocol
     private let visibleRoomsSummaryProvider: RoomSummaryProviderProtocol?
     private let allRoomsSummaryProvider: RoomSummaryProviderProtocol?
@@ -277,9 +273,6 @@ class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol
             return
         }
         
-        let lowerBound = max(0, range.lowerBound - Constants.slidingWindowBoundsPadding)
-        let upperBound = min(Int(visibleRoomsSummaryProvider.countPublisher.value), range.upperBound + Constants.slidingWindowBoundsPadding)
-        
-        visibleRoomsSummaryProvider.updateVisibleRange(lowerBound..<upperBound, timelineLimit: timelineLimit)
+        visibleRoomsSummaryProvider.updateVisibleRange(range, timelineLimit: timelineLimit)
     }
 }
diff --git a/ElementX/Sources/Screens/HomeScreen/View/HomeScreen.swift b/ElementX/Sources/Screens/HomeScreen/View/HomeScreen.swift
index db72659d1..d393582e0 100644
--- a/ElementX/Sources/Screens/HomeScreen/View/HomeScreen.swift
+++ b/ElementX/Sources/Screens/HomeScreen/View/HomeScreen.swift
@@ -17,13 +17,21 @@
 import SwiftUI
 
 struct HomeScreen: View {
+    enum Constants {
+        static let slidingWindowBoundsPadding = 5
+    }
+    
     @ObservedObject var context: HomeScreenViewModel.Context
     
+    @State private var isViewVisible = false
+    
     @State private var scrollViewAdapter = ScrollViewAdapter()
     @State private var showingLogoutConfirmation = false
     @State private var visibleItemIdentifiers = Set<String>() {
         didSet {
-            updateVisibleRange()
+            if isViewVisible {
+                updateVisibleRange()
+            }
         }
     }
     
@@ -69,6 +77,12 @@ struct HomeScreen: View {
                 .disableAutocorrection(true)
             }
         }
+        .onAppear {
+            isViewVisible = true
+        }
+        .onDisappear {
+            isViewVisible = false
+        }
         .introspectScrollView { scrollView in
             guard scrollView != scrollViewAdapter.scrollView else { return }
             scrollViewAdapter.scrollView = scrollView
@@ -198,7 +212,10 @@ struct HomeScreen: View {
             return
         }
         
-        context.send(viewAction: .updateVisibleItemRange(range: firstIndex..<lastIndex, isScrolling: scrollViewAdapter.isScrolling.value))
+        let lowerBound = max(0, firstIndex - Constants.slidingWindowBoundsPadding)
+        let upperBound = min(Int(context.viewState.rooms.count), lastIndex + Constants.slidingWindowBoundsPadding)
+        
+        context.send(viewAction: .updateVisibleItemRange(range: lowerBound..<upperBound, isScrolling: scrollViewAdapter.isScrolling.value))
     }
 }