Don't construct unnecessary view controllers in MainSplitViewController

Tusker.xcodeproj/project.pbxproj

@@ -116,16 +116,15 @@
 		D63569E023908A8D003DD353 /* StatusState.swift in Sources */ = {isa = PBXBuildFile; fileRef = D60A4FFB238B726A008AC647 /* StatusState.swift */; };
 		D63661C02381C144004B9E16 /* PreferencesNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D63661BF2381C144004B9E16 /* PreferencesNavigationController.swift */; };
 		D6370B9C24421FF30092A7FF /* Tusker.xcdatamodeld in Sources */ = {isa = PBXBuildFile; fileRef = D6370B9A24421FF30092A7FF /* Tusker.xcdatamodeld */; };
+		D63A8D0B2561C27F00D9DFFF /* ProfileStatusesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D63A8D0A2561C27F00D9DFFF /* ProfileStatusesViewController.swift */; };
 		D63F9C6E241D2D85004C03CF /* CompositionAttachment.swift in Sources */ = {isa = PBXBuildFile; fileRef = D63F9C6D241D2D85004C03CF /* CompositionAttachment.swift */; };
 		D6403CC224A6B72D00E81C55 /* VisualEffectImageButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6403CC124A6B72D00E81C55 /* VisualEffectImageButton.swift */; };
 		D640D76922BAF5E6004FBE69 /* DomainBlocks.plist in Resources */ = {isa = PBXBuildFile; fileRef = D640D76822BAF5E6004FBE69 /* DomainBlocks.plist */; };
 		D6412B0324AFF6A600F5412E /* TabBarScrollableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6412B0224AFF6A600F5412E /* TabBarScrollableViewController.swift */; };
 		D6412B0524B0227D00F5412E /* ProfileViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6412B0424B0227D00F5412E /* ProfileViewController.swift */; };
-		D6412B0724B0237700F5412E /* ProfileStatusesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6412B0624B0237700F5412E /* ProfileStatusesViewController.swift */; };
 		D6412B0924B0291E00F5412E /* MyProfileViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6412B0824B0291E00F5412E /* MyProfileViewController.swift */; };
 		D6412B0B24B0D4C600F5412E /* ProfileHeaderView.xib in Resources */ = {isa = PBXBuildFile; fileRef = D6412B0A24B0D4C600F5412E /* ProfileHeaderView.xib */; };
 		D6412B0D24B0D4CF00F5412E /* ProfileHeaderView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6412B0C24B0D4CF00F5412E /* ProfileHeaderView.swift */; };
-		D641C773213CAA25004B4513 /* NotificationsTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D641C772213CAA25004B4513 /* NotificationsTableViewController.swift */; };
 		D641C77F213DC78A004B4513 /* InlineTextAttachment.swift in Sources */ = {isa = PBXBuildFile; fileRef = D641C77E213DC78A004B4513 /* InlineTextAttachment.swift */; };
 		D6434EB3215B1856001A919A /* XCBRequest.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6434EB2215B1856001A919A /* XCBRequest.swift */; };
 		D646C956213B365700269FB5 /* LargeImageExpandAnimationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D646C955213B365700269FB5 /* LargeImageExpandAnimationController.swift */; };
@@ -142,6 +141,9 @@
 		D64D0AB12128D9AE005A6F37 /* OnboardingViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D64D0AB02128D9AE005A6F37 /* OnboardingViewController.swift */; };
 		D64D8CA92463B494006B0BAA /* MultiThreadDictionary.swift in Sources */ = {isa = PBXBuildFile; fileRef = D64D8CA82463B494006B0BAA /* MultiThreadDictionary.swift */; };
 		D64F80E2215875CC00BEF393 /* XCBActionType.swift in Sources */ = {isa = PBXBuildFile; fileRef = D64F80E1215875CC00BEF393 /* XCBActionType.swift */; };
+		D65234C9256189D0001AF9CF /* TimelineLikeTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65234C8256189D0001AF9CF /* TimelineLikeTableViewController.swift */; };
+		D65234D325618EFA001AF9CF /* TimelineTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65234D225618EFA001AF9CF /* TimelineTableViewController.swift */; };
+		D65234E12561AA68001AF9CF /* NotificationsTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65234E02561AA68001AF9CF /* NotificationsTableViewController.swift */; };
 		D6531DEE246B81C9000F9538 /* GifvAttachmentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6531DED246B81C9000F9538 /* GifvAttachmentView.swift */; };
 		D6531DF0246B867E000F9538 /* GifvAttachmentViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */; };
 		D6538945214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */; };
@@ -298,7 +300,6 @@
 		D6F1F84D2193B56E00F5FE67 /* Cache.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F1F84C2193B56E00F5FE67 /* Cache.swift */; };
 		D6F2E965249E8BFD005846BB /* CrashReporterViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F2E963249E8BFD005846BB /* CrashReporterViewController.swift */; };
 		D6F2E966249E8BFD005846BB /* CrashReporterViewController.xib in Resources */ = {isa = PBXBuildFile; fileRef = D6F2E964249E8BFD005846BB /* CrashReporterViewController.xib */; };
-		D6F953EC212519E700CF0F2B /* TimelineTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F953EB212519E700CF0F2B /* TimelineTableViewController.swift */; };
 		D6F953F021251A2900CF0F2B /* MastodonController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6F953EF21251A2900CF0F2B /* MastodonController.swift */; };
 		D6FF9860255C717400845181 /* AccountSwitchingContainerViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6FF985F255C717400845181 /* AccountSwitchingContainerViewController.swift */; };
 /* End PBXBuildFile section */
@@ -466,16 +467,15 @@
 		D6333B782139AEFD00CE884A /* Date+TimeAgo.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Date+TimeAgo.swift"; sourceTree = "<group>"; };
 		D63661BF2381C144004B9E16 /* PreferencesNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesNavigationController.swift; sourceTree = "<group>"; };
 		D6370B9B24421FF30092A7FF /* Tusker.xcdatamodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcdatamodel; path = Tusker.xcdatamodel; sourceTree = "<group>"; };
+		D63A8D0A2561C27F00D9DFFF /* ProfileStatusesViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileStatusesViewController.swift; sourceTree = "<group>"; };
 		D63F9C6D241D2D85004C03CF /* CompositionAttachment.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CompositionAttachment.swift; sourceTree = "<group>"; };
 		D6403CC124A6B72D00E81C55 /* VisualEffectImageButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VisualEffectImageButton.swift; sourceTree = "<group>"; };
 		D640D76822BAF5E6004FBE69 /* DomainBlocks.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = DomainBlocks.plist; sourceTree = "<group>"; };
 		D6412B0224AFF6A600F5412E /* TabBarScrollableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TabBarScrollableViewController.swift; sourceTree = "<group>"; };
 		D6412B0424B0227D00F5412E /* ProfileViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileViewController.swift; sourceTree = "<group>"; };
-		D6412B0624B0237700F5412E /* ProfileStatusesViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileStatusesViewController.swift; sourceTree = "<group>"; };
 		D6412B0824B0291E00F5412E /* MyProfileViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MyProfileViewController.swift; sourceTree = "<group>"; };
 		D6412B0A24B0D4C600F5412E /* ProfileHeaderView.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = ProfileHeaderView.xib; sourceTree = "<group>"; };
 		D6412B0C24B0D4CF00F5412E /* ProfileHeaderView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileHeaderView.swift; sourceTree = "<group>"; };
-		D641C772213CAA25004B4513 /* NotificationsTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationsTableViewController.swift; sourceTree = "<group>"; };
 		D641C77E213DC78A004B4513 /* InlineTextAttachment.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InlineTextAttachment.swift; sourceTree = "<group>"; };
 		D6434EB2215B1856001A919A /* XCBRequest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBRequest.swift; sourceTree = "<group>"; };
 		D646C955213B365700269FB5 /* LargeImageExpandAnimationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LargeImageExpandAnimationController.swift; sourceTree = "<group>"; };
@@ -492,6 +492,9 @@
 		D64D0AB02128D9AE005A6F37 /* OnboardingViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OnboardingViewController.swift; sourceTree = "<group>"; };
 		D64D8CA82463B494006B0BAA /* MultiThreadDictionary.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MultiThreadDictionary.swift; sourceTree = "<group>"; };
 		D64F80E1215875CC00BEF393 /* XCBActionType.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBActionType.swift; sourceTree = "<group>"; };
+		D65234C8256189D0001AF9CF /* TimelineLikeTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineLikeTableViewController.swift; sourceTree = "<group>"; };
+		D65234D225618EFA001AF9CF /* TimelineTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineTableViewController.swift; sourceTree = "<group>"; };
+		D65234E02561AA68001AF9CF /* NotificationsTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationsTableViewController.swift; sourceTree = "<group>"; };
 		D6531DED246B81C9000F9538 /* GifvAttachmentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentView.swift; sourceTree = "<group>"; };
 		D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentViewController.swift; sourceTree = "<group>"; };
 		D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TableViewSwipeActionProvider.swift; sourceTree = "<group>"; };
@@ -654,7 +657,6 @@
 		D6F1F84C2193B56E00F5FE67 /* Cache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Cache.swift; sourceTree = "<group>"; };
 		D6F2E963249E8BFD005846BB /* CrashReporterViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CrashReporterViewController.swift; sourceTree = "<group>"; };
 		D6F2E964249E8BFD005846BB /* CrashReporterViewController.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = CrashReporterViewController.xib; sourceTree = "<group>"; };
-		D6F953EB212519E700CF0F2B /* TimelineTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineTableViewController.swift; sourceTree = "<group>"; };
 		D6F953EF21251A2900CF0F2B /* MastodonController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MastodonController.swift; sourceTree = "<group>"; };
 		D6FF985F255C717400845181 /* AccountSwitchingContainerViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AccountSwitchingContainerViewController.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -973,7 +975,7 @@
 			isa = PBXGroup;
 			children = (
 				D6BC9DD6232D7811002CA326 /* TimelinesPageViewController.swift */,
-				D6F953EB212519E700CF0F2B /* TimelineTableViewController.swift */,
+				D65234D225618EFA001AF9CF /* TimelineTableViewController.swift */,
 				D6945C3123AC4D36005C403C /* HashtagTimelineViewController.swift */,
 				D6945C3723AC739F005C403C /* InstanceTimelineViewController.swift */,
 			);
@@ -1005,7 +1007,7 @@
 			isa = PBXGroup;
 			children = (
 				D6412B0424B0227D00F5412E /* ProfileViewController.swift */,
-				D6412B0624B0237700F5412E /* ProfileStatusesViewController.swift */,
+				D63A8D0A2561C27F00D9DFFF /* ProfileStatusesViewController.swift */,
 				D6412B0824B0291E00F5412E /* MyProfileViewController.swift */,
 			);
 			path = Profile;
@@ -1023,7 +1025,7 @@
 			isa = PBXGroup;
 			children = (
 				D6BC9DB0232C61BC002CA326 /* NotificationsPageViewController.swift */,
-				D641C772213CAA25004B4513 /* NotificationsTableViewController.swift */,
+				D65234E02561AA68001AF9CF /* NotificationsTableViewController.swift */,
 			);
 			path = Notifications;
 			sourceTree = "<group>";
@@ -1372,6 +1374,7 @@
 				D6412B0224AFF6A600F5412E /* TabBarScrollableViewController.swift */,
 				D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */,
 				D6B81F3B2560365300F6E31D /* RefreshableViewController.swift */,
+				D65234C8256189D0001AF9CF /* TimelineLikeTableViewController.swift */,
 			);
 			path = Utilities;
 			sourceTree = "<group>";
@@ -1851,6 +1854,7 @@
 				D6BC9DB3232D4C07002CA326 /* WellnessPrefsView.swift in Sources */,
 				D64BC18F23C18B9D000D0238 /* FollowRequestNotificationTableViewCell.swift in Sources */,
 				D693DE5923FE24310061E07D /* InteractivePushTransition.swift in Sources */,
+				D65234C9256189D0001AF9CF /* TimelineLikeTableViewController.swift in Sources */,
 				D6A3BC8A2321F79B00FD64D5 /* AccountTableViewCell.swift in Sources */,
 				D66A77BB233838DC0058F1EC /* UIFont+Traits.swift in Sources */,
 				D68FEC4F232C5BC300C84F23 /* SegmentedPageViewController.swift in Sources */,
@@ -1865,7 +1869,6 @@
 				D6F953F021251A2900CF0F2B /* MastodonController.swift in Sources */,
 				0411610022B442870030A9B7 /* LoadingLargeImageViewController.swift in Sources */,
 				D6A4DCE525537C7A00D9DE31 /* FastSwitchingAccountView.swift in Sources */,
-				D6412B0724B0237700F5412E /* ProfileStatusesViewController.swift in Sources */,
 				D6A4DCCC2553667800D9DE31 /* FastAccountSwitcherViewController.swift in Sources */,
 				D611C2CF232DC61100C86A49 /* HashtagTableViewCell.swift in Sources */,
 				D627944F23A9C99800D38C68 /* EditListAccountsViewController.swift in Sources */,
@@ -1887,6 +1890,7 @@
 				D6CA6A92249FAD8900AD45C1 /* AudioSessionHelper.swift in Sources */,
 				D6C143FD25354FD0007DC240 /* EmojiCollectionViewCell.swift in Sources */,
 				D60D2B8223844C71001B87A3 /* BaseStatusTableViewCell.swift in Sources */,
+				D63A8D0B2561C27F00D9DFFF /* ProfileStatusesViewController.swift in Sources */,
 				D60E2F272442372B005F8713 /* StatusMO.swift in Sources */,
 				D60E2F2C24423EAD005F8713 /* LazilyDecoding.swift in Sources */,
 				D677284A24ECBDF400C732D3 /* ComposeCurrentAccount.swift in Sources */,
@@ -1988,6 +1992,7 @@
 				D6FF9860255C717400845181 /* AccountSwitchingContainerViewController.swift in Sources */,
 				D670F8B62537DC890046588A /* EmojiPickerWrapper.swift in Sources */,
 				D6B81F442560390300F6E31D /* MenuController.swift in Sources */,
+				D65234E12561AA68001AF9CF /* NotificationsTableViewController.swift in Sources */,
 				D67C57AF21E28EAD00C3118B /* Array+Uniques.swift in Sources */,
 				D6945C3223AC4D36005C403C /* HashtagTimelineViewController.swift in Sources */,
 				D647D92824257BEB0005044F /* AttachmentPreviewViewController.swift in Sources */,
@@ -1997,7 +2002,6 @@
 				D681E4D7246E32290053414F /* StatusActivityItemSource.swift in Sources */,
 				D646C95A213B5D0500269FB5 /* LargeImageInteractionController.swift in Sources */,
 				D6A3BC7C232195C600FD64D5 /* ActionNotificationGroupTableViewCell.swift in Sources */,
-				D6F953EC212519E700CF0F2B /* TimelineTableViewController.swift in Sources */,
 				D62275A824F1CA2800B82A16 /* ComposeReplyContentView.swift in Sources */,
 				D677284824ECBCB100C732D3 /* ComposeView.swift in Sources */,
 				D68232F72464F4FD00325FB8 /* ComposeDrawingViewController.swift in Sources */,
@@ -2007,12 +2011,12 @@
 				D68015402401A6BA00D6103B /* ComposingPrefsView.swift in Sources */,
 				D67895BC24671E6D00D4CD9E /* PKDrawing+Render.swift in Sources */,
 				04D14BB022B34A2800642648 /* GalleryViewController.swift in Sources */,
-				D641C773213CAA25004B4513 /* NotificationsTableViewController.swift in Sources */,
 				D6C1B2082545D1EC00DAAA66 /* StatusCardView.swift in Sources */,
 				D6412B0524B0227D00F5412E /* ProfileViewController.swift in Sources */,
 				D64BC18A23C16487000D0238 /* UnpinStatusActivity.swift in Sources */,
 				D64D8CA92463B494006B0BAA /* MultiThreadDictionary.swift in Sources */,
 				D6757A7C2157E01900721E32 /* XCBManager.swift in Sources */,
+				D65234D325618EFA001AF9CF /* TimelineTableViewController.swift in Sources */,
 				D68E6F5F253C9B2D001A1B4C /* BaseEmojiLabel.swift in Sources */,
 				D6F1F84D2193B56E00F5FE67 /* Cache.swift in Sources */,
 				D6F0B12B24A3071C001E48C3 /* MainSplitViewController.swift in Sources */,

Tusker/Screens/Lists/ListTimelineViewController.swift

@@ -58,8 +58,7 @@ class ListTimelineViewController: TimelineTableViewController {
         dismiss(animated: true)
         
         // todo: show loading indicator
-        timelineSegments = []
+        reloadInitialItems()
-        loadInitialStatuses()
     }
 
 }

Tusker/Screens/Main/MainSplitViewController.swift

@@ -53,7 +53,11 @@ class MainSplitViewController: UISplitViewController {
         primaryBackgroundStyle = .sidebar
 
         setViewController(EnhancedNavigationViewController(), for: .secondary)
+        // don't unnecesarily construct a content VC unless the we're in actually split mode
+        // when we change from compact -> split for the first time, the VC will be transferred anyways
+        if traitCollection.horizontalSizeClass != .compact {
             select(item: .tab(.timelines))
+        }
         
         tabBarViewController = MainTabBarViewController(mastodonController: mastodonController)
         setViewController(tabBarViewController, for: .compact)

Tusker/Screens/Notifications/NotificationsTableViewController.swift

@@ -9,7 +9,7 @@
 import UIKit
 import Pachyderm
 
-class NotificationsTableViewController: EnhancedTableViewController {
+class NotificationsTableViewController: TimelineLikeTableViewController<NotificationGroup> {
 
     private let statusCell = "statusCell"
     private let actionGroupCell = "actionGroupCell"
@@ -20,125 +20,112 @@ class NotificationsTableViewController: EnhancedTableViewController {
     weak var mastodonController: MastodonController!
     
     private let excludedTypes: [Pachyderm.Notification.Kind]
-    private let groupTypes = [Notification.Kind.favourite, .reblog, .follow]
+    private let groupTypes = [Pachyderm.Notification.Kind.favourite, .reblog, .follow]
     
-    private var loaded = false
-
-    private var groups: [NotificationGroup] = []
-    
-    private let pageSize = 20
     private var newer: RequestRange?
     private var older: RequestRange?
     
-    private var lastLastVisibleRow: IndexPath?
-    
     init(allowedTypes: [Pachyderm.Notification.Kind], mastodonController: MastodonController) {
         self.excludedTypes = Array(Set(Pachyderm.Notification.Kind.allCases).subtracting(allowedTypes))
         self.mastodonController = mastodonController
         
-        super.init(style: .plain)
+        super.init()
-
-        #if !targetEnvironment(macCatalyst)
-        self.refreshControl = UIRefreshControl()
-        refreshControl!.addTarget(self, action: #selector(refreshNotifications), for: .valueChanged)
-        #endif
-        
-        addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: NSLocalizedString("Refresh Notifications", comment: "refresh notifications command discoverability title")))
     }
     
-    required init?(coder aDecoder: NSCoder) {
+    required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
     
+    override class func refreshCommandTitle() -> String {
+        return NSLocalizedString("Refresh Notifications", comment: "refresh notifications command discoverability title")
+    }
+    
     override func viewDidLoad() {
         super.viewDidLoad()
         
-        tableView.rowHeight = UITableView.automaticDimension
-        tableView.estimatedRowHeight = 140
-        
         tableView.register(UINib(nibName: "TimelineStatusTableViewCell", bundle: .main), forCellReuseIdentifier: statusCell)
         tableView.register(UINib(nibName: "ActionNotificationGroupTableViewCell", bundle: .main), forCellReuseIdentifier: actionGroupCell)
         tableView.register(UINib(nibName: "FollowNotificationGroupTableViewCell", bundle: .main), forCellReuseIdentifier: followGroupCell)
         tableView.register(UINib(nibName: "FollowRequestNotificationTableViewCell", bundle: .main), forCellReuseIdentifier: followRequestCell)
         tableView.register(UINib(nibName: "BasicTableViewCell", bundle: .main), forCellReuseIdentifier: unknownCell)
-        
-        tableView.prefetchDataSource = self
     }
     
-    override func viewWillAppear(_ animated: Bool) {
+    override func loadInitialItems(completion: @escaping ([NotificationGroup]) -> Void) {
-        super.viewWillAppear(animated)
-        
-        if !loaded {
-            loaded = true
-            
         let request = Client.getNotifications(excludeTypes: excludedTypes)
-            mastodonController.run(request) { result in
+        mastodonController.run(request) { (response) in
-                guard case let .success(notifications, pagination) = result else { fatalError() }
+            guard case let .success(notifications, pagination) = response else { fatalError() }
             
             let groups = NotificationGroup.createGroups(notifications: notifications, only: self.groupTypes)
             
-                self.groups.append(contentsOf: groups)
-                
             self.newer = pagination?.newer
             self.older = pagination?.older
             
             self.mastodonController.persistentContainer.addAll(notifications: notifications) {
-                    DispatchQueue.main.async {
+                completion(groups)
-                        self.tableView.reloadData()
-                    }
-                }
             }
         }
     }
     
-    override func viewWillDisappear(_ animated: Bool) {
+    override func loadOlder(completion: @escaping ([NotificationGroup]) -> Void) {
-        super.viewWillDisappear(animated)
+        guard let older = older else {
-        
+            completion([])
-        pruneOffscreenRows()
-    }
-    
-    private func pruneOffscreenRows() {
-        guard let lastVisibleRow = lastLastVisibleRow else {
             return
         }
-        let lastRowIndex = groups.count - 1
         
-        if lastVisibleRow.row < lastRowIndex - pageSize {
+        let request = Client.getNotifications(excludeTypes: excludedTypes, range: older)
-            // if there are more than 20 rows below the lats visible one
+        mastodonController.run(request) { (response) in
+            guard case let .success(newNotifications, pagination) = response else { fatalError() }
             
-            let rowIndicesToRemove = (lastVisibleRow.row + pageSize)..<groups.count
+            self.older = pagination?.older
             
-            let groupsToRemove = groups[rowIndicesToRemove]
+            let groups = NotificationGroup.createGroups(notifications: newNotifications, only: self.groupTypes)
-            for group in groupsToRemove {
+            
-                for notification in group.notifications {
+            self.mastodonController.persistentContainer.addAll(notifications: newNotifications) {
-                    if let id = notification.status?.id {
+                completion(groups)
-                        mastodonController.persistentContainer.status(for: id)?.decrementReferenceCount()
             }
         }
     }
     
-            groups.removeSubrange(rowIndicesToRemove)
+    override func loadNewer(completion: @escaping ([NotificationGroup]) -> Void) {
+        guard let newer = newer else {
+            completion([])
+            return
+        }
         
-            let removedIndexPaths = rowIndicesToRemove.map { IndexPath(row: $0, section: 0) }
+        let request = Client.getNotifications(excludeTypes: excludedTypes, range: newer)
-            UIView.performWithoutAnimation {
+        mastodonController.run(request) { (response) in
-                tableView.deleteRows(at: removedIndexPaths, with: .none)
+            guard case let .success(newNotifications, pagination) = response else { fatalError() }
+            
+            self.newer = pagination?.newer
+            
+            let groups = NotificationGroup.createGroups(notifications: newNotifications, only: self.groupTypes)
+            
+            self.mastodonController.persistentContainer.addAll(notifications: newNotifications) {
+                completion(groups)
             }
         }
     }
     
-    // MARK: - Table view data source
+    private func dismissNotificationsInGroup(at indexPath: IndexPath, completion: (() -> Void)? = nil) {
-
+        let group = DispatchGroup()
-    override func numberOfSections(in tableView: UITableView) -> Int {
+        item(for: indexPath).notifications
-        return 1
+            .map { Pachyderm.Notification.dismiss(id: $0.id) }
+            .forEach { (request) in
+                group.enter()
+                mastodonController.run(request) { (_) in
+                    group.leave()
+                }
+            }
+        group.notify(queue: .main) {
+            self.sections[indexPath.section].remove(at: indexPath.row)
+            self.tableView.deleteRows(at: [indexPath], with: .automatic)
+            completion?()
+        }
     }
     
-    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+    // MARK: - UITableViewDataSource
-        return groups.count
-    }
-
-    
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
-        let group = groups[indexPath.row]
+        let group = item(for: indexPath)
         
         switch group.kind {
         case .mention:
@@ -176,45 +163,7 @@ class NotificationsTableViewController: EnhancedTableViewController {
         }
     }
     
-    // MARK: - Table view delegate
+    // MARK: - UITableViewDelegate
-
-    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
-        lastLastVisibleRow = tableView.indexPathsForVisibleRows?.last
-        
-        if indexPath.row == groups.count - 1 {
-            guard let older = older else { return }
-            
-            let request = Client.getNotifications(excludeTypes: excludedTypes, range: older)
-            mastodonController.run(request) { result in
-                guard case let .success(newNotifications, pagination) = result else { fatalError() }
-                
-                let groups = NotificationGroup.createGroups(notifications: newNotifications, only: self.groupTypes)
-                
-                let newIndexPaths = (self.groups.count..<(self.groups.count + groups.count)).map {
-                    IndexPath(row: $0, section: 0)
-                }
-                self.groups.append(contentsOf: groups)
-
-                self.older = pagination?.older
-                
-                self.mastodonController.persistentContainer.addAll(notifications: newNotifications) {
-                    DispatchQueue.main.async {
-                        UIView.performWithoutAnimation {
-                            self.tableView.insertRows(at: newIndexPaths, with: .automatic)
-                        }
-                    }
-                }
-            }
-        }
-    }
-    
-    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
-        return true
-    }
-    
-    override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
-        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
-    }
     
     override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
         let dismissAction = UIContextualAction(style: .destructive, title: NSLocalizedString("Dismiss", comment: "dismiss notification swipe action title")) { (action, view, completion) in
@@ -223,7 +172,9 @@ class NotificationsTableViewController: EnhancedTableViewController {
             }
         }
         dismissAction.image = UIImage(systemName: "clear.fill")
+        
         let cellConfiguration = (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
+        
         let config: UISwipeActionsConfiguration
         if let cellConfiguration = cellConfiguration {
             config = UISwipeActionsConfiguration(actions: cellConfiguration.actions + [dismissAction])
@@ -237,78 +188,27 @@ class NotificationsTableViewController: EnhancedTableViewController {
     
     override func getSuggestedContextMenuActions(tableView: UITableView, indexPath: IndexPath, point: CGPoint) -> [UIAction] {
         return [
-            UIAction(title: "Dismiss Notification", image: UIImage(systemName: "clear.fill"), identifier: .init("dismissnotification"), discoverabilityTitle: nil, attributes: [], state: .off, handler: { (_) in
+            UIAction(title: "Dismiss Notification", image: UIImage(systemName: "clear.fill"), identifier: .init("dismissnotification"), handler: { (_) in
                 self.dismissNotificationsInGroup(at: indexPath)
             })
         ]
     }
-    
-    func dismissNotificationsInGroup(at indexPath: IndexPath, completion: (() -> Void)? = nil) {
-        let group = DispatchGroup()
-        groups[indexPath.row].notifications
-            .map { Pachyderm.Notification.dismiss(id: $0.id) }
-            .forEach { (request) in
-                group.enter()
-                mastodonController.run(request) { (response) in
-                    group.leave()
-                }
-        }
-        group.notify(queue: .main) {
-            self.groups.remove(at: indexPath.row)
-            self.tableView.deleteRows(at: [indexPath], with: .automatic)
-            completion?()
-        }
-    }
-    
-    @objc func refreshNotifications() {
-        guard let newer = newer else { return }
-        
-        let request = Client.getNotifications(excludeTypes: excludedTypes, range: newer)
-        mastodonController.run(request) { result in
-            guard case let .success(newNotifications, pagination) = result else { fatalError() }
-            
-            let groups = NotificationGroup.createGroups(notifications: newNotifications, only: self.groupTypes)
-            
-            self.groups.insert(contentsOf: groups, at: 0)
-            
-            if let newer = pagination?.newer {
-                self.newer = newer
-            }
-            
-            self.mastodonController.persistentContainer.addAll(notifications: newNotifications) {
-                DispatchQueue.main.async {
-                    let newIndexPaths = (0..<groups.count).map {
-                        IndexPath(row: $0, section: 0)
-                    }
-                    UIView.performWithoutAnimation {
-                        self.tableView.insertRows(at: newIndexPaths, with: .automatic)
-                    }
-                    
-                    self.refreshControl?.endRefreshing()
-                    
-                    // maintain the current position in the list (don't scroll to top)
-                    self.tableView.scrollToRow(at: IndexPath(row: newNotifications.count, section: 0), at: .top, animated: false)
-                }
-            }
-        }
 }
 
+extension NotificationsTableViewController: TuskerNavigationDelegate {
+    var apiController: MastodonController { mastodonController }
 }
 
 extension NotificationsTableViewController: StatusTableViewCellDelegate {
-    var apiController: MastodonController { mastodonController }
     func statusCellCollapsedStateChanged(_ cell: BaseStatusTableViewCell) {
-        // causes the table view to recalculate the cell heights
+        cellHeightChanged()
-        tableView.beginUpdates()
-        tableView.endUpdates()
     }
 }
 
 extension NotificationsTableViewController: UITableViewDataSourcePrefetching {
     func tableView(_ tableView: UITableView, prefetchRowsAt indexPaths: [IndexPath]) {
         for indexPath in indexPaths {
-            for notification in groups[indexPath.row].notifications {
+            for notification in item(for: indexPath).notifications {
-                // todo: this account object could be stale
                 _ = ImageCache.avatars.get(notification.account.avatar, completion: nil)
             }
         }
@@ -316,21 +216,9 @@ extension NotificationsTableViewController: UITableViewDataSourcePrefetching {
     
     func tableView(_ tableView: UITableView, cancelPrefetchingForRowsAt indexPaths: [IndexPath]) {
         for indexPath in indexPaths {
-            for notification in groups[indexPath.row].notifications {
+            for notification in item(for: indexPath).notifications {
                 ImageCache.avatars.cancelWithoutCallback(notification.account.avatar)
             }
         }
     }
 }
-
-extension NotificationsTableViewController: RefreshableViewController {
-    func refresh() {
-        refreshNotifications()
-    }
-}
-
-extension NotificationsTableViewController: BackgroundableViewController {
-    func sceneDidEnterBackground() {
-        pruneOffscreenRows()
-    }
-}

Tusker/Screens/Profile/ProfileStatusesViewController.swift

@@ -9,7 +9,7 @@
 import UIKit
 import Pachyderm
 
-class ProfileStatusesViewController: EnhancedTableViewController {
+class ProfileStatusesViewController: TimelineLikeTableViewController<TimelineEntry> {
     
     weak var mastodonController: MastodonController!
     
@@ -19,20 +19,15 @@ class ProfileStatusesViewController: EnhancedTableViewController {
     
     let kind: Kind
     
-    private var pinnedStatuses: [(id: String, state: StatusState)] = []
-    private var timelineSegments: [[(id: String, state: StatusState)]] = []
-    
     private var older: RequestRange?
     private var newer: RequestRange?
     
-    var loaded = false
-    
     init(accountID: String?, kind: Kind, mastodonController: MastodonController) {
         self.accountID = accountID
         self.kind = kind
         self.mastodonController = mastodonController
         
-        super.init(style: .plain)
+        super.init()
     }
     
     required init?(coder: NSCoder) {
@@ -42,76 +37,117 @@ class ProfileStatusesViewController: EnhancedTableViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
         
-        view.backgroundColor = .systemBackground
-        
-        #if !targetEnvironment(macCatalyst)
-        refreshControl = UIRefreshControl()
-        refreshControl!.addTarget(self, action: #selector(refreshStatuses), for: .valueChanged)
-        #endif
-        
-        addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: NSLocalizedString("Refresh Statuses", comment: "refresh statuses command discoverability title")))
-        
-        tableView.rowHeight = UITableView.automaticDimension
-        tableView.estimatedRowHeight = 140
-        
         tableView.register(UINib(nibName: "TimelineStatusTableViewCell", bundle: .main), forCellReuseIdentifier: "statusCell")
-        
-        tableView.prefetchDataSource = self
-    }
-    
-    override func viewWillAppear(_ animated: Bool) {
-        super.viewWillAppear(animated)
-        
-        if !loaded,
-           let accountID = accountID,
-           let account = mastodonController.persistentContainer.account(for: accountID) {
-            updateUI(account: account)
-        }
     }
     
     func updateUI(account: AccountMO) {
-        guard !loaded else { return }
+        loadInitial()
-        loaded = true
+    }
     
-        if kind == .statuses {
+    override class func refreshCommandTitle() -> String {
+        return NSLocalizedString("Refresh Statuses", comment: "refresh statuses command discoverability title")
+    }
+    
+    override func headerSectionsCount() -> Int {
+        return 1
+    }
+    
+    override func loadInitial() {
+        guard accountID != nil else {
+            return
+        }
+        
+        if !loaded {
+            loadPinnedStatuses()
+        }
+        
+        super.loadInitial()
+    }
+    
+    private func loadPinnedStatuses() {
+        guard kind == .statuses else {
+            return
+        }
         getPinnedStatuses { (response) in
-                guard case let .success(statuses, _) = response else {
+            guard case let .success(statuses, _) = response,
+                  !statuses.isEmpty else {
                 // todo: error message
                 return
             }
-                if statuses.isEmpty { return }
             
             self.mastodonController.persistentContainer.addAll(statuses: statuses) {
-                    self.pinnedStatuses = statuses.map { ($0.id, .unknown) }
+                let items = statuses.map { ($0.id, StatusState.unknown) }
-                    let indexPaths = (0..<statuses.count).map { IndexPath(row: $0, section: 0) }
                 DispatchQueue.main.async {
                     UIView.performWithoutAnimation {
-                            self.tableView.insertRows(at: indexPaths, with: .none)
+                        if self.sections.count < 1 {
+                            self.sections.append(items)
+                            self.tableView.insertSections(IndexSet(integer: 0), with: .none)
+                        } else {
+                            self.sections[0] = items
+                            self.tableView.reloadSections(IndexSet(integer: 0), with: .none)
+                        }
                     }
                 }
             }
         }
     }
     
+    override func loadInitialItems(completion: @escaping ([TimelineEntry]) -> Void) {
         getStatuses { (response) in
-            guard case let .success(statuses, pagination) = response else {
+            guard case let .success(statuses, pagination) = response,
+                  !statuses.isEmpty else {
                 // todo: error message
                 return
             }
-            if statuses.isEmpty { return }
-            
-            self.mastodonController.persistentContainer.addAll(statuses: statuses) {
-                self.timelineSegments.append(statuses.map { ($0.id, .unknown) })
             
             self.older = pagination?.older
             self.newer = pagination?.newer
             
-                DispatchQueue.main.async {
+            self.mastodonController.persistentContainer.addAll(statuses: statuses) {
-                    UIView.performWithoutAnimation {
+                completion(statuses.map { ($0.id, .unknown) })
-                        self.tableView.insertSections(IndexSet(integer: 1), with: .none)
             }
         }
     }
+    
+    override func loadOlder(completion: @escaping ([TimelineEntry]) -> Void) {
+        guard let older = older else {
+            completion([])
+            return
+        }
+        
+        getStatuses(for: older) { (response) in
+            guard case let .success(statuses, pagination) = response else {
+                // todo: error message
+                completion([])
+                return
+            }
+            
+            self.older = pagination?.older
+            
+            self.mastodonController.persistentContainer.addAll(statuses: statuses) {
+                completion(statuses.map { ($0.id, .unknown) })
+            }
+        }
+    }
+    
+    override func loadNewer(completion: @escaping ([TimelineEntry]) -> Void) {
+        guard let newer = newer else {
+            completion([])
+            return
+        }
+        
+        getStatuses(for: newer) { (response) in
+            guard case let .success(statuses, pagination) = response else {
+                // todo: error message
+                completion([])
+                return
+            }
+            
+            self.newer = pagination?.newer
+            
+            self.mastodonController.persistentContainer.addAll(statuses: statuses) {
+                completion(statuses.map { ($0.id, .unknown) })
+            }
         }
     }
     
@@ -133,47 +169,19 @@ class ProfileStatusesViewController: EnhancedTableViewController {
         mastodonController.run(request, completion: completion)
     }
     
-    // MARK: Interaction
+    override func refresh() {
-    
+        super.refresh()
-    @objc func refreshStatuses() {
-        guard let newer = newer else { return }
-        
-        getStatuses(for: newer) { (response) in
-            guard case let .success(newStatuses, pagination) = response else {
-                // todo: error message
-                return
-            }
-            
-            self.mastodonController.persistentContainer.addAll(statuses: newStatuses) {
-                // if there's no newer request range (because no statuses were returned),
-                // we don't want to change the current newer pagination, so that we can
-                // continue to load statuses newer than whatever was last loaded
-                if let newer = pagination?.newer {
-                    self.newer = newer
-                }
-                
-                let indexPaths = (0..<newStatuses.count).map { IndexPath(row: $0, section: 1) }
-                DispatchQueue.main.async {
-                    self.timelineSegments[0].insert(contentsOf: newStatuses.map { ($0.id, .unknown) }, at: 0)
-                    UIView.performWithoutAnimation {
-                        self.tableView.insertRows(at: indexPaths, with: .none)
-                    }
-                    
-                    self.refreshControl?.endRefreshing()
-                }
-            }
-        }
         
         if kind == .statuses {
             getPinnedStatuses { (response) in
-                guard case let .success(newPinnedStatuses, _) = response else {
+                guard case let .success(newPinnedStatues, _) = response else {
                     // todo: error message
                     return
                 }
                 
-                self.mastodonController.persistentContainer.addAll(statuses: newPinnedStatuses) {
+                self.mastodonController.persistentContainer.addAll(statuses: newPinnedStatues) {
-                    let oldPinnedStatuses = self.pinnedStatuses
+                    let oldPinnedStatuses = self.sections[0]
-                    let pinnedStatuses = newPinnedStatuses.map { (status) -> (id: String, state: StatusState) in
+                    let pinnedStatues = newPinnedStatues.map { (status) -> TimelineEntry in
                         let state: StatusState
                         if let (_, oldState) = oldPinnedStatuses.first(where: { $0.id == status.id }) {
                             state = oldState
@@ -183,7 +191,11 @@ class ProfileStatusesViewController: EnhancedTableViewController {
                         return (status.id, state)
                     }
                     DispatchQueue.main.async {
-                        self.pinnedStatuses = pinnedStatuses
+                        if self.sections.count < 1 {
+                            self.sections.append(pinnedStatues)
+                        } else {
+                            self.sections[0] = pinnedStatues
+                        }
                         UIView.performWithoutAnimation {
                             self.tableView.reloadSections(IndexSet(integer: 0), with: .none)
                         }
@@ -193,83 +205,19 @@ class ProfileStatusesViewController: EnhancedTableViewController {
         }
     }
     
-    // MARK: Table view data source
+    // MARK: - UITableViewDatasource
-
-    override func numberOfSections(in tableView: UITableView) -> Int {
-        // 1 for pinned, rest for timeline
-        return 1 + timelineSegments.count
-    }
-
-    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        if section == 0 {
-            return pinnedStatuses.count
-        } else {
-            return timelineSegments[section - 1].count
-        }
-    }
-
-    
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         let cell = tableView.dequeueReusableCell(withIdentifier: "statusCell", for: indexPath) as! TimelineStatusTableViewCell
         
         cell.delegate = self
+        cell.showPinned = indexPath.section == 0
         
-        if indexPath.section == 0 {
+        let (id, state) = item(for: indexPath)
-            cell.showPinned = true
-            let (id, state) = pinnedStatuses[indexPath.row]
         cell.updateUI(statusID: id, state: state)
-        } else {
-            cell.showPinned = false
-            let (id, state) = timelineSegments[indexPath.section - 1][indexPath.row]
-            cell.updateUI(statusID: id, state: state)
-        }
         
         return cell
     }
     
-    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
-        // load older statuses if at bottom
-        if timelineSegments.count > 0,
-           indexPath.section == timelineSegments.count,
-           indexPath.row == timelineSegments[indexPath.section - 1].count - 1 {
-            guard let older = older else { return }
-            
-            getStatuses(for: older) { (response) in
-                guard case let .success(newStatuses, pagination) = response else {
-                    // todo: error message
-                    return
-                }
-                
-                self.mastodonController.persistentContainer.addAll(statuses: newStatuses) {
-                    // if there is no older request range, we want to set ours to nil
-                    // otherwise we would end up loading the same statuses again
-                    self.older = pagination?.older
-                    
-                    DispatchQueue.main.async {
-                        let start = self.timelineSegments[indexPath.section - 1].count
-                        let indexPaths = (0..<newStatuses.count).map { IndexPath(row: start + $0, section: indexPath.section) }
-                        self.timelineSegments[indexPath.section - 1].append(contentsOf: newStatuses.map { ($0.id, .unknown) })
-                        UIView.performWithoutAnimation {
-                            self.tableView.insertRows(at: indexPaths, with: .none)
-                        }
-                    }
-                }
-            }
-        }
-    }
-    
-    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
-        return true
-    }
-    
-    override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
-        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
-    }
-    
-    override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
-        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
-    }
-
 }
 
 extension ProfileStatusesViewController {
@@ -278,26 +226,25 @@ extension ProfileStatusesViewController {
     }
 }
 
-extension ProfileStatusesViewController: StatusTableViewCellDelegate {
+extension ProfileStatusesViewController: TuskerNavigationDelegate {
     var apiController: MastodonController { mastodonController }
+}
 
+extension ProfileStatusesViewController: StatusTableViewCellDelegate {
     func statusCellCollapsedStateChanged(_ cell: BaseStatusTableViewCell) {
-        // causes the table view to recalculate the cell heights
+        cellHeightChanged()
-        tableView.beginUpdates()
-        tableView.endUpdates()
     }
 }
 
 extension ProfileStatusesViewController: UITableViewDataSourcePrefetching {
     func tableView(_ tableView: UITableView, prefetchRowsAt indexPaths: [IndexPath]) {
         for indexPath in indexPaths {
-            let statusID: String
+            let statusID = item(for: indexPath).id
-            if indexPath.section == 0 {
+            
-                statusID = pinnedStatuses[indexPath.row].id
+            guard let status = mastodonController.persistentContainer.status(for: statusID) else {
-            } else {
+                continue
-                statusID = timelineSegments[indexPath.section - 1][indexPath.row].id
             }
-            guard let status = mastodonController.persistentContainer.status(for: statusID) else { continue }
+            
             _ = ImageCache.avatars.get(status.account.avatar, completion: nil)
             for attachment in status.attachments where attachment.kind == .image {
                 _ = ImageCache.attachments.get(attachment.url, completion: nil)
@@ -307,13 +254,11 @@ extension ProfileStatusesViewController: UITableViewDataSourcePrefetching {
     
     func tableView(_ tableView: UITableView, cancelPrefetchingForRowsAt indexPaths: [IndexPath]) {
         for indexPath in indexPaths {
-            let statusID: String
+            let statusID = item(for: indexPath).id
-            if indexPath.section == 0 {
+            
-                statusID = pinnedStatuses[indexPath.row].id
+            guard let status = mastodonController.persistentContainer.status(for: statusID) else {
-            } else {
+                continue
-                statusID = timelineSegments[indexPath.section - 1][indexPath.row].id
             }
-            guard let status = mastodonController.persistentContainer.status(for: statusID) else { continue }
             ImageCache.avatars.cancelWithoutCallback(status.account.avatar)
             for attachment in status.attachments where attachment.kind == .image {
                 ImageCache.avatars.cancelWithoutCallback(attachment.url)
@@ -321,9 +266,3 @@ extension ProfileStatusesViewController: UITableViewDataSourcePrefetching {
         }
     }
 }
-
-extension ProfileStatusesViewController: RefreshableViewController {
-    func refresh() {
-        refreshStatuses()
-    }
-}

Tusker/Screens/Timeline/TimelineTableViewController.swift

@@ -1,5 +1,5 @@
 //
-//  StatusesTableViewController.swift
+//  TimelineTableViewController.swift
 //  Tusker
 //
 //  Created by Shadowfacts on 8/15/18.
@@ -9,41 +9,29 @@
 import UIKit
 import Pachyderm
 
-class TimelineTableViewController: EnhancedTableViewController, StatusTableViewCellDelegate {
+typealias TimelineEntry = (id: String, state: StatusState)
 
-    var timeline: Timeline!
+class TimelineTableViewController: TimelineLikeTableViewController<TimelineEntry> {
+    
+    let timeline: Timeline
     weak var mastodonController: MastodonController!
     
-    private var loaded = false
-    
-    var timelineSegments: [[(id: String, state: StatusState)]] = []
-    
-    private let pageSize = 20
     private var newer: RequestRange?
     private var older: RequestRange?
     
-    private var lastLastVisibleRow: IndexPath?
-    
     init(for timeline: Timeline, mastodonController: MastodonController) {
         self.timeline = timeline
         self.mastodonController = mastodonController
         
-        super.init(style: .plain)
+        super.init()
         
         title = timeline.title
         tabBarItem.image = timeline.tabBarImage
         
-        #if !targetEnvironment(macCatalyst)
-        self.refreshControl = UIRefreshControl()
-        refreshControl!.addTarget(self, action: #selector(refreshStatuses), for: .valueChanged)
-        #endif
-        
-        addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: NSLocalizedString("Refresh Statuses", comment: "refresh statuses command discoverability title")))
-        
         userActivity = UserActivityManager.showTimelineActivity(timeline: timeline)
     }
     
-    required init?(coder aDecoder: NSCoder) {
+    required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
     
@@ -52,120 +40,89 @@ class TimelineTableViewController: EnhancedTableViewController, StatusTableViewC
         // decrement reference counts of any statuses we still have
         // if the app is currently being quit, this will not affect the persisted data because
         // the persistent container would already have been saved in SceneDelegate.sceneDidEnterBackground(_:)
-        for segment in timelineSegments {
+        for section in sections {
-            for (id, _) in segment {
+            for (id, _) in section {
                 persistentContainer.status(for: id)?.decrementReferenceCount()
             }
         }
     }
     
-    func statusID(for indexPath: IndexPath) -> String {
-        return timelineSegments[indexPath.section][indexPath.row].id
-    }
-    
     override func viewDidLoad() {
         super.viewDidLoad()
         
-        tableView.rowHeight = UITableView.automaticDimension
+        tableView.register(UINib(nibName: "TimelineStatusTableViewCell", bundle: .main), forCellReuseIdentifier: "statusCell")
-        tableView.estimatedRowHeight = 140
-        
-        tableView.register(UINib(nibName: "TimelineStatusTableViewCell", bundle: nil), forCellReuseIdentifier: "statusCell")
-        
-        tableView.prefetchDataSource = self
     }
     
-    override func viewWillAppear(_ animated: Bool) {
+    override class func refreshCommandTitle() -> String {
-        super.viewWillAppear(animated)
+        return NSLocalizedString("Refresh Statuses", comment: "refresh status command discoverability title")
-        
-        loadInitialStatuses()
     }
     
-    override func viewWillDisappear(_ animated: Bool) {
+    override func willRemoveRows(at indexPaths: [IndexPath]) {
-        super.viewWillDisappear(animated)
+        for indexPath in indexPaths {
-        
+            let id = item(for: indexPath).id
-        pruneOffscreenRows()
+            mastodonController.persistentContainer.status(for: id)?.decrementReferenceCount()
+        }
     }
     
-    func loadInitialStatuses() {
+    override func loadInitialItems(completion: @escaping ([TimelineEntry]) -> Void) {
-        guard !loaded else { return }
-        loaded = true
-        
         let request = Client.getStatuses(timeline: timeline)
-        mastodonController.run(request) { response in
+        
+        mastodonController?.run(request) { (response) in
             guard case let .success(statuses, pagination) = response else { fatalError() }
-            // todo: possible race condition here? we update the underlying data before waiting to reload the table view
+            
-            self.timelineSegments.insert(statuses.map { ($0.id, .unknown) }, at: 0)
             self.newer = pagination?.newer
             self.older = pagination?.older
-            self.mastodonController.persistentContainer.addAll(statuses: statuses) {
+            
-                DispatchQueue.main.async {
+            self.mastodonController?.persistentContainer.addAll(statuses: statuses) {
-                    self.tableView.reloadData()
+                completion(statuses.map { ($0.id, .unknown) })
-                }
             }
         }
     }
     
-    private func pruneOffscreenRows() {
+    override func loadOlder(completion: @escaping ([TimelineEntry]) -> Void) {
-        guard let lastVisibleRow = lastLastVisibleRow else {
+        guard let older = older else {
+            completion([])
             return
         }
-        let lastSectionIndex = timelineSegments.count - 1
         
-        if lastVisibleRow.section < lastSectionIndex {
+        let request = Client.getStatuses(timeline: timeline, range: older)
-            // if there is a section below the last visible one
         
-            let sectionsToRemove = (lastVisibleRow.section + 1)...lastSectionIndex
+        mastodonController.run(request) { (response) in
+            guard case let .success(statuses, pagination) = response else { fatalError() }
             
-            for section in sectionsToRemove {
+            self.older = pagination?.older
-                for (id, _) in timelineSegments.remove(at: section) {
-                    mastodonController.persistentContainer.status(for: id)?.decrementReferenceCount()
-                }
-            }
-            
-            UIView.performWithoutAnimation {
-                tableView.deleteSections(IndexSet(sectionsToRemove), with: .none)
-            }
-            
-        } else if lastVisibleRow.section == lastSectionIndex {
-            let lastSection = timelineSegments.last!
-            let lastRowIndex = lastSection.count - 1
-            
-            if lastVisibleRow.row < lastRowIndex - 20 {
-                // if there are more than 20 rows in the current section below the last visible one
-                
-                let rowIndicesInLastSectionToRemove = (lastVisibleRow.row + 20)..<lastSection.count
-                
-                let statusesToRemove = lastSection[rowIndicesInLastSectionToRemove]
-                for (id, _) in statusesToRemove {
-                    mastodonController.persistentContainer.status(for: id)?.decrementReferenceCount()
-                }
-                
-                timelineSegments[lastSectionIndex].removeSubrange(rowIndicesInLastSectionToRemove)
-
-                let removedIndexPaths = rowIndicesInLastSectionToRemove.map { IndexPath(row: $0, section: lastSectionIndex) }
-                UIView.performWithoutAnimation {
-                    tableView.deleteRows(at: removedIndexPaths, with: .none)
-                }
             
+            self.mastodonController?.persistentContainer.addAll(statuses: statuses) {
+                completion(statuses.map { ($0.id, .unknown) })
             }
         }
     }
     
-    // MARK: - Table view data source
+    override func loadNewer(completion: @escaping ([TimelineEntry]) -> Void) {
-
+        guard let newer = newer else {
-    override func numberOfSections(in tableView: UITableView) -> Int {
+            completion([])
-        return timelineSegments.count
+            return
         }
         
-    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+        let request = Client.getStatuses(timeline: timeline, range: newer)
-        return timelineSegments[section].count
+        
+        mastodonController.run(request) { (response) in
+            guard case let .success(statuses, pagination) = response else { fatalError() }
+            
+            self.newer = pagination?.newer
+            
+            self.mastodonController?.persistentContainer.addAll(statuses: statuses) {
+                completion(statuses.map { ($0.id, .unknown) })
+            }
+        }
     }
     
+    // MARK: - UITableViewDataSource
     
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         guard let cell = tableView.dequeueReusableCell(withIdentifier: "statusCell", for: indexPath) as? TimelineStatusTableViewCell else { fatalError() }
 
-        let (id, state) = timelineSegments[indexPath.section][indexPath.row]
+        let (id, state) = item(for: indexPath)
         cell.delegate = self
 
         cell.updateUI(statusID: id, state: state)
@@ -173,104 +130,24 @@ class TimelineTableViewController: EnhancedTableViewController, StatusTableViewC
         return cell
     }
     
-    // MARK: - Table view delegate
-    
-    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
-        // this assumes that indexPathsForVisibleRows is always in order
-        lastLastVisibleRow = tableView.indexPathsForVisibleRows?.last
-        
-        // load older statuses, if necessary
-        if indexPath.section == timelineSegments.count - 1,
-            indexPath.row == timelineSegments[indexPath.section].count - 1 {
-            guard let older = older else { return }
-            
-            let request = Client.getStatuses(timeline: timeline, range: older)
-            mastodonController.run(request) { response in
-                guard case let .success(newStatuses, pagination) = response else { fatalError() }
-                self.older = pagination?.older
-                self.mastodonController.persistentContainer.addAll(statuses: newStatuses) {
-                    DispatchQueue.main.async {
-                        let newRows = self.timelineSegments.last!.count..<(self.timelineSegments.last!.count + newStatuses.count)
-                        let newIndexPaths = newRows.map { IndexPath(row: $0, section: self.timelineSegments.count - 1) }
-                        self.timelineSegments[self.timelineSegments.count - 1].append(contentsOf: newStatuses.map { ($0.id, .unknown) })
-                        
-                        UIView.performWithoutAnimation {
-                            self.tableView.insertRows(at: newIndexPaths, with: .none)
-                        }
-                    }
-                }
-            }
-        }
 }
 
-    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
+extension TimelineTableViewController: TuskerNavigationDelegate {
-        return true
-    }
-    
-    override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
-        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
-    }
-    
-    override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
-        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
-    }
-    
-    // MARK: - Interaction
-    
-    @objc func refreshStatuses() {
-        guard let newer = newer else { return }
-        
-        let request = Client.getStatuses(timeline: timeline, range: newer)
-        mastodonController.run(request) { response in
-            guard case let .success(newStatuses, pagination) = response else { fatalError() }
-            
-            // If there is no new newer pagination, don't reset it, so that the user can continue refreshing for more recent statuses
-            // Otherwise, when no new statuses were loaded, it would get reset and the the user would be unable to refresh
-            if let newer = pagination?.newer {
-                self.newer = newer
-            }
-            
-            self.mastodonController.persistentContainer.addAll(statuses: newStatuses) {
-                DispatchQueue.main.async {
-                    self.timelineSegments[0].insert(contentsOf: newStatuses.map { ($0.id, .unknown) }, at: 0)
-                    let newIndexPaths = (0..<newStatuses.count).map {
-                        IndexPath(row: $0, section: 0)
-                    }
-                    UIView.performWithoutAnimation {
-                        self.tableView.insertRows(at: newIndexPaths, with: .automatic)
-                    }
-                    
-                    self.refreshControl?.endRefreshing()
-                    
-                    // maintain the current position in the list (don't scroll to the top)
-                    self.tableView.scrollToRow(at: IndexPath(row: newStatuses.count, section: 0), at: .top, animated: false)
-                }
-            }
-        }
-    }
-
-    @objc func composePressed(_ sender: Any) {
-        compose()
-    }
-    
-    // MARK: - TuskerNavigationDelegate
-    
     var apiController: MastodonController { mastodonController }
-    
-    // MARK: - StatusTableViewCellDelegate
-    
-    func statusCellCollapsedStateChanged(_ cell: BaseStatusTableViewCell) {
-        // causes the table view to recalculate the cell heights
-        tableView.beginUpdates()
-        tableView.endUpdates()
 }
 
+extension TimelineTableViewController: StatusTableViewCellDelegate {
+    func statusCellCollapsedStateChanged(_ cell: BaseStatusTableViewCell) {
+        cellHeightChanged()
+    }
 }
 
 extension TimelineTableViewController: UITableViewDataSourcePrefetching {
     func tableView(_ tableView: UITableView, prefetchRowsAt indexPaths: [IndexPath]) {
         for indexPath in indexPaths {
-            guard let status = mastodonController.persistentContainer.status(for: statusID(for: indexPath)) else { continue }
+            guard let status = mastodonController.persistentContainer.status(for: item(for: indexPath).id) else {
+                continue
+            }
             _ = ImageCache.avatars.get(status.account.avatar, completion: nil)
             for attachment in status.attachments where attachment.kind == .image {
                 _ = ImageCache.attachments.get(attachment.url, completion: nil)
@@ -282,8 +159,11 @@ extension TimelineTableViewController: UITableViewDataSourcePrefetching {
         for indexPath in indexPaths {
             // todo: this means when removing cells, we can't cancel prefetching
             // is this an issue?
-            guard indexPath.section < timelineSegments.count, indexPath.row < timelineSegments[indexPath.section].count,
+            guard indexPath.section < sections.count,
-                let status = mastodonController.persistentContainer.status(for: statusID(for: indexPath)) else { continue }
+                  indexPath.row < sections[indexPath.section].count,
+                  let status = mastodonController.persistentContainer.status(for: item(for: indexPath).id) else {
+                continue
+            }
             ImageCache.avatars.cancelWithoutCallback(status.account.avatar)
             for attachment in status.attachments where attachment.kind == .image {
                 ImageCache.attachments.cancelWithoutCallback(attachment.url)
@@ -291,15 +171,3 @@ extension TimelineTableViewController: UITableViewDataSourcePrefetching {
         }
     }
 }
-
-extension TimelineTableViewController: RefreshableViewController {
-    func refresh() {
-        refreshStatuses()
-    }
-}
-
-extension TimelineTableViewController: BackgroundableViewController {
-    func sceneDidEnterBackground() {
-        pruneOffscreenRows()
-    }
-}

Tusker/Screens/Utilities/TimelineLikeTableViewController.swift

@@ -0,0 +1,243 @@
+//
+//  TimelineLikeTableViewController.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 11/15/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+
+/// A table view controller that manages common functionality  between timeline-like UIs.
+// For example, this class handles loading new items when the user scrolls to the end,
+// refreshing, and pruning offscreen rows automatically.
+class TimelineLikeTableViewController<Item>: EnhancedTableViewController, RefreshableViewController {
+
+    private(set) var loaded = false
+    
+    var sections: [[Item]] = []
+    
+    private let pageSize = 20
+    
+    private var lastLastVisibleRow: IndexPath?
+    
+    init() {
+        super.init(style: .plain)
+        
+        #if !targetEnvironment(macCatalyst)
+        self.refreshControl = UIRefreshControl()
+        self.refreshControl!.addTarget(self, action: #selector(refresh), for: .valueChanged)
+        #endif
+        
+        addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: Self.refreshCommandTitle()))
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    func item(for indexPath: IndexPath) -> Item {
+        return sections[indexPath.section][indexPath.row]
+    }
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        
+        tableView.rowHeight = UITableView.automaticDimension
+        tableView.estimatedRowHeight = 140
+        
+        if let prefetchSource = self as? UITableViewDataSourcePrefetching {
+            tableView.prefetchDataSource = prefetchSource
+        }
+    }
+    
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        
+        loadInitial()
+    }
+    
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        
+        pruneOffscreenRows()
+    }
+    
+    func loadInitial() {
+        guard !loaded else { return }
+        loaded = true
+        
+        loadInitialItems() { (items) in
+            guard items.count > 0 else { return }
+            DispatchQueue.main.async {
+                if self.sections.count < self.headerSectionsCount() {
+                    self.sections.insert(contentsOf: Array(repeating: [], count: self.headerSectionsCount() - self.sections.count), at: 0)
+                }
+                
+                self.sections.append(items)
+                
+                self.tableView.reloadData()
+            }
+        }
+    }
+    
+    func reloadInitialItems() {
+        loaded = false
+        sections = []
+        loadInitial()
+    }
+    
+    func cellHeightChanged() {
+        // causes the table view to recalculate the cell heights
+        tableView.beginUpdates()
+        tableView.endUpdates()
+    }
+    
+    class func refreshCommandTitle() -> String {
+        return "Refresh"
+    }
+    
+    func loadInitialItems(completion: @escaping ([Item]) -> Void) {
+        fatalError("loadInitialItems(completion:) must be implemented by subclasses")
+    }
+    
+    func loadOlder(completion: @escaping ([Item]) -> Void) {
+        fatalError("loadOlder(completion:) must be implemented by subclasses")
+    }
+    
+    func loadNewer(completion: @escaping ([Item]) -> Void) {
+        fatalError("loadNewer(completion:) must be implemented by subclasses")
+    }
+    
+    func willRemoveRows(at indexPaths: [IndexPath]) {
+    }
+    
+    func headerSectionsCount() -> Int {
+        return 0
+    }
+    
+    private func pruneOffscreenRows() {
+        guard let lastVisibleRow = lastLastVisibleRow else {
+            return
+        }
+        let lastSectionIndex = sections.count - 1
+        
+        if lastVisibleRow.section < lastSectionIndex {
+            // if there is a section below the last visible one
+            
+            let sectionsToRemove = (lastVisibleRow.section + 1)...lastSectionIndex
+            
+            let indexPathsToRemove = sectionsToRemove.flatMap { (section) in
+                sections[section].indices.map { (row) in
+                    IndexPath(row: row, section: section)
+                }
+            }
+            willRemoveRows(at: indexPathsToRemove)
+            
+            sections.removeSubrange(sectionsToRemove)
+            
+            UIView.performWithoutAnimation {
+                tableView.deleteSections(IndexSet(sectionsToRemove), with: .none)
+            }
+        } else if lastVisibleRow.section == lastSectionIndex {
+            let lastSection = sections.last!
+            let lastRowIndex = lastSection.count - 1
+            
+            if lastVisibleRow.row < lastRowIndex - pageSize {
+                // if there are more than pageSize rows in the current section below the last visible one
+                
+                let rowIndicesInLastSectionToRemove = (lastVisibleRow.row + 20)..<lastSection.count
+                
+                let indexPathsToRemove = rowIndicesInLastSectionToRemove.map {
+                    IndexPath(row: $0, section: lastSectionIndex)
+                }
+                willRemoveRows(at: indexPathsToRemove)
+                
+                sections[lastSectionIndex].removeSubrange(rowIndicesInLastSectionToRemove)
+                
+                UIView.performWithoutAnimation {
+                    tableView.deleteRows(at: indexPathsToRemove, with: .none)
+                }
+            }
+        }
+        
+    }
+    
+    // MARK: - UITableViewDataSource
+    override func numberOfSections(in tableView: UITableView) -> Int {
+        return sections.count
+    }
+    
+    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+        return sections[section].count
+    }
+    
+    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
+        fatalError("tableView(_:cellForRowAt:) must be implemented by subclasses")
+    }
+    
+    // MARK: - UITableViewDelegate
+    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
+        // this assumes that indexPathsForVisibleRows is always in order
+        lastLastVisibleRow = tableView.indexPathsForVisibleRows?.last
+        
+        if indexPath.section == sections.count - 1,
+           indexPath.row == sections[indexPath.section].count - 1 {
+            loadOlder() { (newItems) in
+                guard newItems.count > 0 else { return }
+                
+                DispatchQueue.main.async {
+                    let newRows = self.sections.last!.count..<(self.sections.last!.count + newItems.count)
+                    let newIndexPaths = newRows.map { IndexPath(row: $0, section: self.sections.count - 1) }
+                    
+                    self.sections[self.sections.count - 1].append(contentsOf: newItems)
+                    
+                    UIView.performWithoutAnimation {
+                        self.tableView.insertRows(at: newIndexPaths, with: .none)
+                    }
+                }
+            }
+        }
+    }
+    
+    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
+        return true
+    }
+    
+    override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
+        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
+    }
+    
+    override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
+        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
+    }
+    
+    // MARK: - RefreshableViewController
+    func refresh() {
+        loadNewer() { (newItems) in
+            DispatchQueue.main.async {
+                self.refreshControl?.endRefreshing()
+                
+                guard newItems.count > 0 else { return }
+                
+                let firstNonHeaderSection = self.headerSectionsCount()
+                
+                self.sections[firstNonHeaderSection].insert(contentsOf: newItems, at: 0)
+                
+                let newIndexPaths = (0..<newItems.count).map { IndexPath(row: $0, section: firstNonHeaderSection) }
+                UIView.performWithoutAnimation {
+                    self.tableView.insertRows(at: newIndexPaths, with: .none)
+                }
+
+                // maintain the current position in the list (don't scroll to top)
+                self.tableView.scrollToRow(at: IndexPath(row: newItems.count, section: firstNonHeaderSection), at: .top, animated: false)
+            }
+        }
+    }
+}
+
+extension TimelineLikeTableViewController: BackgroundableViewController {
+    func sceneDidEnterBackground() {
+        pruneOffscreenRows()
+    }
+}