Lists in new sidebar

Tusker/Screens/Main/NewMainTabBarViewController.swift

@@ -7,12 +7,20 @@
 //
 
 import UIKit
+import Combine
+import Pachyderm
 
 @available(iOS 18.0, *)
 class NewMainTabBarViewController: BaseMainTabBarViewController {
     
     private let composePlaceholder = UIViewController()
     
+    private var listsGroup: UITabGroup!
+    
+    private var cancellables = Set<AnyCancellable>()
+    
+    private var navigationStacks = [String: [UIViewController]]()
+
     override func viewDidLoad() {
         super.viewDidLoad()
         
@@ -26,19 +34,54 @@ class NewMainTabBarViewController: BaseMainTabBarViewController {
             self.makeViewController(for: tab)
         }
         
-        let topLevelTabs = [
+        let homeTab = UITab(title: "Home", image: UIImage(systemName: "house"), identifier: Tab.home.rawValue, viewControllerProvider: viewControllerProvider)
-            Tab.home,
+        let notificationsTab = UITab(title: "Notifications", image: UIImage(systemName: "bell"), identifier: Tab.notifications.rawValue, viewControllerProvider: viewControllerProvider)
-            .notifications,
+        let composeTab = UITab(title: "Compose", image: UIImage(systemName: "pencil"), identifier: Tab.compose.rawValue, viewControllerProvider: viewControllerProvider)
-            .compose,
+        let exploreTab = UITab(title: "Explore", image: UIImage(systemName: "magnifyingglass"), identifier: Tab.explore.rawValue, viewControllerProvider: viewControllerProvider)
-            .explore,
+        let bookmarksTab = UITab(title: "Bookmarks", image: UIImage(systemName: "bookmark"), identifier: Tab.bookmarks.rawValue, viewControllerProvider: viewControllerProvider)
-            .myProfile
+        bookmarksTab.preferredPlacement = .optional
-        ].map {
+        let favoritesTab = UITab(title: "Favorites", image: UIImage(systemName: "star"), identifier: Tab.favorites.rawValue, viewControllerProvider: viewControllerProvider)
-            UITab(title: $0.title, image: UIImage(systemName: $0.imageName), identifier: $0.rawValue, viewControllerProvider: viewControllerProvider)
+        favoritesTab.preferredPlacement = .optional
+        let myProfileTab = UITab(title: "My Profile", image: UIImage(systemName: "person"), identifier: Tab.myProfile.rawValue, viewControllerProvider: viewControllerProvider)
+        
+        listsGroup = UITabGroup(title: "Lists", image: nil, identifier: Tab.lists.rawValue, children: []) { _ in
+            // this closure is necessary to prevent UIKit from crashing (FB14860961)
+            return MultiColumnNavigationController()
+        }
+        listsGroup.preferredPlacement = .sidebarOnly
+        listsGroup.sidebarActions = [
+            UIAction(title: "New List…", image: UIImage(systemName: "plus"), handler: { _ in
+                fatalError("TODO")
+            })
+        ]
+        reloadLists(mastodonController.lists)
+        
+        if UIDevice.current.userInterfaceIdiom == .phone {
+            self.tabs = [
+                homeTab,
+                notificationsTab,
+                composeTab,
+                exploreTab,
+                myProfileTab,
+            ]
+        } else {
+            self.tabs = [
+                homeTab,
+                notificationsTab,
+                exploreTab,
+                bookmarksTab,
+                favoritesTab,
+                myProfileTab,
+                composeTab,
+                listsGroup,
+            ]
         }
         
-        self.tabs = topLevelTabs
-        
         setupFastAccountSwitcher()
+        
+        mastodonController.$lists
+            .sink { [unowned self] in self.reloadLists($0) }
+            .store(in: &cancellables)
     }
     
     private func makeViewController(for tab: UITab) -> UIViewController {
@@ -55,9 +98,19 @@ class NewMainTabBarViewController: BaseMainTabBarViewController {
             return composePlaceholder
         case .explore:
             root = ExploreViewController(mastodonController: mastodonController)
+        case .bookmarks:
+            root = BookmarksViewController(mastodonController: mastodonController)
+        case .favorites:
+            root = FavoritesViewController(mastodonController: mastodonController)
         case .myProfile:
             root = MyProfileViewController(mastodonController: mastodonController)
+        case .lists:
+            fatalError("unreachable")
         }
+        return NewMainTabBarViewController.embedInNavigationController(root)
+    }
+    
+    private static func embedInNavigationController(_ vc: UIViewController) -> UIViewController {
         let nav: any NavigationControllerProtocol
         if UIDevice.current.userInterfaceIdiom == .phone {
             nav = EnhancedNavigationViewController()
@@ -72,10 +125,18 @@ class NewMainTabBarViewController: BaseMainTabBarViewController {
                 nav = MultiColumnNavigationController()
             }
         }
-        nav.viewControllers = [root]
+        nav.viewControllers = [vc]
         return nav
     }
     
+    private func reloadLists(_ lists: [List]) {
+        listsGroup.children = lists.map { list in
+            UITab(title: list.title, image: UIImage(systemName: "list.bullet"), identifier: "list:\(list.id)") { [unowned self] _ in
+                NewMainTabBarViewController.embedInNavigationController(ListTimelineViewController(for: list, mastodonController: self.mastodonController))
+            }
+        }
+    }
+    
     @objc func handleComposeKeyCommand() {
         compose(editing: nil)
     }
@@ -94,37 +155,11 @@ extension NewMainTabBarViewController {
         case notifications
         case compose
         case explore
+        case bookmarks
+        case favorites
         case myProfile
         
-        var title: String {
+        case lists
-            switch self {
-            case .home:
-                "Home"
-            case .notifications:
-                "Notifications"
-            case .compose:
-                "Compose"
-            case .explore:
-                "Explore"
-            case .myProfile:
-                "My Profile"
-            }
-        }
-        
-        var imageName: String {
-            switch self {
-            case .home:
-                "house"
-            case .notifications:
-                "bell"
-            case .compose:
-                "pencil"
-            case .explore:
-                "magnifyingglass"
-            case .myProfile:
-                "person"
-            }
-        }
     }
 }
 
@@ -156,6 +191,34 @@ extension NewMainTabBarViewController: UITabBarControllerDelegate {
         if let vc = newTab.viewController as? MultiColumnNavigationController {
             self.updateViewControllerSafeAreaInsets(vc)
         }
+        
+        // All tabs in a tab group deliberately share the same view controller, so we have to do this ourselves.
+        // I think this is pretty unfortunate API design--half the time, the tab bar controller takes care of
+        // this, but the rest of the time it's up to you.
+        // The managingNavigationController API would theoretically solve this, but split-screen/multi-column
+        // nav can't straightforwardly be implemented as UINavigationController subclasses.
+        // Unfortunately this, in turn, means that when switching between tabs in the same group, we don't
+        // get the new transition animation.
+        // This would be much less complicated if the controller just used the individual VCs of items in a group.
+        if let group = newTab.parent,
+           group.identifier == Tab.lists.rawValue,
+           let nav = group.viewController as? any NavigationControllerProtocol {
+            if let multiColumn = nav as? MultiColumnNavigationController {
+                updateViewControllerSafeAreaInsets(multiColumn)
+            }
+            
+            if let previousTab {
+                navigationStacks[previousTab.identifier] = nav.viewControllers
+            }
+            
+            if let existing = navigationStacks[newTab.identifier] {
+                nav.viewControllers = existing
+            } else if let newNav = newTab.viewController as? any NavigationControllerProtocol {
+                nav.viewControllers = newNav.viewControllers
+            } else {
+                fatalError("unreachable")
+            }
+        }
     }
 }