From a47667c15bffdec88de6ba20aee43f2f951b5721 Mon Sep 17 00:00:00 2001
From: Justin Mazzocchi <2831158+jzzocc@users.noreply.github.com>
Date: Wed, 2 Sep 2020 00:39:42 -0700
Subject: [PATCH] Fix scroll position maintenance

---
 View Controllers/StatusListViewController.swift         | 8 +++++---
 ViewModels/Sources/ViewModels/StatusListViewModel.swift | 4 +++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/View Controllers/StatusListViewController.swift b/View Controllers/StatusListViewController.swift
index 0f2328a..10e2215 100644
--- a/View Controllers/StatusListViewController.swift	
+++ b/View Controllers/StatusListViewController.swift	
@@ -70,10 +70,12 @@ class StatusListViewController: UITableViewController {
                 self.dataSource.apply($0.snapshot(), animatingDifferences: false) {
                     if
                         let id = self.viewModel.maintainScrollPositionOfStatusID,
-                        let indexPath = self.dataSource.indexPath(for: id),
-                        let offsetFromNavigationBar = offsetFromNavigationBar {
+                        let indexPath = self.dataSource.indexPath(for: id) {
                         self.tableView.scrollToRow(at: indexPath, at: .top, animated: false)
-                        self.tableView.contentOffset.y -= offsetFromNavigationBar
+
+                        if let offsetFromNavigationBar = offsetFromNavigationBar {
+                            self.tableView.contentOffset.y -= offsetFromNavigationBar
+                        }
                     }
                 }
             }
diff --git a/ViewModels/Sources/ViewModels/StatusListViewModel.swift b/ViewModels/Sources/ViewModels/StatusListViewModel.swift
index 88e2d6d..bcb845c 100644
--- a/ViewModels/Sources/ViewModels/StatusListViewModel.swift
+++ b/ViewModels/Sources/ViewModels/StatusListViewModel.swift
@@ -92,8 +92,10 @@ private extension StatusListViewModel {
     func determineIfScrollPositionShouldBeMaintained(newStatusSections: [[Status]]) {
         maintainScrollPositionOfStatusID = nil // clear old value
 
+        let flatStatusIDs = statusIDs.reduce([], +)
+
         // Maintain scroll position of parent after initial load of context
-        if let contextParentID = contextParentID, statusIDs.reduce([], +) == [contextParentID] {
+        if let contextParentID = contextParentID, flatStatusIDs == [contextParentID] || flatStatusIDs == [] {
             maintainScrollPositionOfStatusID = contextParentID
         }
     }