Fix changing list reply policy not reloading list timeline

Closes #215

Also fix interactive dismissal of edit screen not reloading list

Tusker/Screens/Lists/EditListAccountsViewController.swift

@@ -17,7 +17,7 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
     
     private var state = State.unloaded
     
-    private(set) var changedAccounts = false
+    private(set) var shouldReloadListTimeline = false
     
     private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
     var collectionView: UICollectionView! { view as? UICollectionView }
@@ -186,7 +186,7 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
     
     @MainActor
     private func loadAccounts() async {
-        guard state == .unloaded else { return }
+        guard state == .unloaded || state == .loaded else { return }
         
         state = .loading
         
@@ -278,7 +278,7 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
     }
     
     private func addAccount(id: String) async {
-        changedAccounts = true
+        shouldReloadListTimeline = true
         do {
             let req = List.add(list.id, accounts: [id])
             _ = try await mastodonController.run(req)
@@ -294,11 +294,19 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
     }
     
     private func removeAccount(id: String) async {
-        changedAccounts = true
+        shouldReloadListTimeline = true
         do {
             let request = List.remove(list.id, accounts: [id])
             _ = try await mastodonController.run(request)
-            await self.loadAccounts()
+            
+            var snapshot = dataSource.snapshot()
+            if snapshot.itemIdentifiers.contains(.account(id: id)) {
+                snapshot.deleteItems([.account(id: id)])
+                await MainActor.run {
+                    dataSource.apply(snapshot)
+                }
+            }
+            
         } catch {
             let config = ToastConfiguration(from: error, with: "Error Removing Account", in: self) { [unowned self] toast in
                 toast.dismissToast(animated: true)
@@ -309,6 +317,7 @@ class EditListAccountsViewController: UIViewController, CollectionViewController
     }
     
     private func setReplyPolicy(_ replyPolicy: List.ReplyPolicy) {
+        shouldReloadListTimeline = true
         Task {
             let service = EditListSettingsService(list: list, mastodonController: mastodonController, present: { self.present($0, animated: true) })
             await service.run(replyPolicy: replyPolicy)

Tusker/Screens/Lists/ListTimelineViewController.swift

@@ -16,6 +16,8 @@ class ListTimelineViewController: TimelineViewController {
     
     var presentEditOnAppear = false
     
+    private var noContentView: UIStackView!
+    
     private var listRenamedCancellable: AnyCancellable?
     
     init(for list: List, mastodonController: MastodonController) {
@@ -53,6 +55,39 @@ class ListTimelineViewController: TimelineViewController {
         }
     }
     
+    private func createNoContentView() {
+        let title = UILabel()
+        title.textColor = .secondaryLabel
+        title.font = .preferredFont(forTextStyle: .title1).withTraits(.traitBold)!
+        title.adjustsFontForContentSizeCategory = true
+        title.text = "No Posts"
+        
+        let subtitle = UILabel()
+        subtitle.textColor = .secondaryLabel
+        subtitle.font = .preferredFont(forTextStyle: .body)
+        subtitle.adjustsFontForContentSizeCategory = true
+        subtitle.numberOfLines = 0
+        subtitle.textAlignment = .center
+        subtitle.text = "This list doesn't currently have any posts. Edit it to add accounts if necessary."
+        
+        noContentView = UIStackView(arrangedSubviews: [
+            title,
+            subtitle,
+        ])
+        noContentView.axis = .vertical
+        noContentView.spacing = 8
+        noContentView.alignment = .center
+        noContentView.isAccessibilityElement = true
+        noContentView.accessibilityLabel = subtitle.text
+        noContentView.translatesAutoresizingMaskIntoConstraints = false
+        view.addSubview(noContentView)
+        NSLayoutConstraint.activate([
+            noContentView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
+            noContentView.leadingAnchor.constraint(equalToSystemSpacingAfter: view.safeAreaLayoutGuide.leadingAnchor, multiplier: 1),
+            view.safeAreaLayoutGuide.trailingAnchor.constraint(equalToSystemSpacingAfter: noContentView.trailingAnchor, multiplier: 1),
+        ])
+    }
+    
     private func listChanged() {
         title = list.title
     }
@@ -61,10 +96,23 @@ class ListTimelineViewController: TimelineViewController {
         let editListAccountsController = EditListAccountsViewController(list: list, mastodonController: mastodonController)
         editListAccountsController.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(editListDoneButtonPressed))
         let navController = UINavigationController(rootViewController: editListAccountsController)
+        navController.sheetPresentationController?.delegate = self
         present(navController, animated: animated)
     }
     
-    // MARK: - Interaction
+    private func reloadIfNecessary(editViewController: EditListAccountsViewController) {
+        guard editViewController.shouldReloadListTimeline else {
+            return
+        }
+        noContentView?.removeFromSuperview()
+        noContentView = nil
+        Task {
+            applyInitialSnapshot()
+            await controller.loadInitial()
+        }
+    }
+    
+    // MARK: Interaction
     
     @objc func editListButtonPressed() {
         presentEdit(animated: true)
@@ -75,12 +123,28 @@ class ListTimelineViewController: TimelineViewController {
         
         dismiss(animated: true)
         
-        if presented?.changedAccounts == true {
-            Task {
-                applyInitialSnapshot()
-                await controller.loadInitial()
-            }
+        if let presented {
+            self.reloadIfNecessary(editViewController: presented)
         }
     }
+    
+    // MARK: TimelineLikeControllerDelegate
+    
+    override func handleReplaceAllItems(_ timelineItems: [String]) async {
+        if timelineItems.isEmpty {
+            createNoContentView()
+        }
+        await super.handleReplaceAllItems(timelineItems)
+    }
 
 }
+
+extension ListTimelineViewController: UISheetPresentationControllerDelegate {
+    func presentationControllerWillDismiss(_ presentationController: UIPresentationController) {
+        guard let nav = presentationController.presentedViewController as? UINavigationController,
+              let edit = nav.viewControllers.first as? EditListAccountsViewController else {
+            return
+        }
+        reloadIfNecessary(editViewController: edit)
+    }
+}

Tusker/Screens/Timeline/TimelineViewController.swift

@@ -1015,7 +1015,19 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
             }
         }
         self.showToast(configuration: config, animated: true)
+    }    
+    
+    // this is copied from the TimelineLikeCollectionViewController implementation because it needs to be overridable by ListTimelineViewController
+    func handleReplaceAllItems(_ timelineItems: [String]) async {
+        var snapshot = dataSource.snapshot()
+        if snapshot.sectionIdentifiers.contains(.entries) {
+            snapshot.deleteSections([.entries])
+        }
+        snapshot.appendSections([.entries])
+        snapshot.appendItems(timelineItems.map { .fromTimelineItem($0) }, toSection: .entries)
+        await apply(snapshot, animatingDifferences: false)
     }
+
 }
 
 extension TimelineViewController {