feat: update navigation stack when transition from .regular to .compact

Mastodon.xcodeproj/project.pbxproj

@@ -2536,6 +2536,8 @@
 			isa = PBXGroup;
 			children = (
 				DB852D1B26FB021500FC9D81 /* RootSplitViewController.swift */,
+				DB852D1A26FAED0100FC9D81 /* Sidebar */,
+				DB8AF54E25C13703002E6C99 /* MainTab */,
 			);
 			path = Root;
 			sourceTree = "<group>";
@@ -2652,8 +2654,6 @@
 				2D7631A425C1532200929FB9 /* Share */,
 				DB6180E426391A500018D199 /* Transition */,
 				DB852D1D26FB021900FC9D81 /* Root */,
-				DB852D1A26FAED0100FC9D81 /* Sidebar */,
-				DB8AF54E25C13703002E6C99 /* MainTab */,
 				DB01409B25C40BB600F9F3CF /* Onboarding */,
 				DB9F58ED26EF435800E7BBE9 /* Account */,
 				2D38F1D325CD463600561493 /* HomeTimeline */,

Mastodon/Coordinator/SceneCoordinator.swift

@@ -18,6 +18,8 @@ final public class SceneCoordinator {
     
     let id = UUID().uuidString
     
+    weak var splitViewController: RootSplitViewController?
+    
     init(scene: UIScene, sceneDelegate: SceneDelegate, appContext: AppContext) {
         self.scene = scene
         self.sceneDelegate = sceneDelegate
@@ -119,6 +121,7 @@ extension SceneCoordinator {
     
     func setup() {
         let splitViewController = RootSplitViewController(context: appContext, coordinator: self)
+        self.splitViewController = splitViewController
         sceneDelegate.window?.rootViewController = splitViewController
     }
     
@@ -172,8 +175,14 @@ extension SceneCoordinator {
         
         switch transition {
         case .show:
-            presentingViewController.show(viewController, sender: sender)
+            if let splitViewController = splitViewController, !splitViewController.isCollapsed,
-            
+               let supplementaryViewController = splitViewController.viewController(for: .supplementary) as? UINavigationController,
+               (supplementaryViewController === presentingViewController || supplementaryViewController.viewControllers.contains(presentingViewController))
+            {
+                fallthrough
+            } else {
+                presentingViewController.show(viewController, sender: sender)
+            }
         case .showDetail:
             let navigationController = AdaptiveStatusBarStyleNavigationController(rootViewController: viewController)
             presentingViewController.showDetailViewController(navigationController, sender: sender)

Mastodon/Protocol/StatusProvider/StatusProviderFacade.swift

@@ -111,10 +111,10 @@ extension StatusProviderFacade {
                     if provider.navigationController == nil {
                         let from = provider.presentingViewController ?? provider
                         provider.dismiss(animated: true) {
-                            provider.coordinator.present(scene: .thread(viewModel: threadViewModel), from: from, transition: .showDetail)
+                            provider.coordinator.present(scene: .thread(viewModel: threadViewModel), from: from, transition: .show)
                         }
                     } else {
-                        provider.coordinator.present(scene: .thread(viewModel: threadViewModel), from: provider, transition: .showDetail)
+                        provider.coordinator.present(scene: .thread(viewModel: threadViewModel), from: provider, transition: .show)
                     }
                 }
             }

Mastodon/Scene/Root/MainTab/MainTabBarController.swift

@@ -24,7 +24,7 @@ class MainTabBarController: UITabBarController {
 
     let wizard = Wizard()
     
-    var currentTab = Tab.home
+    var currentTab = CurrentValueSubject<Tab, Never>(.home)
         
     enum Tab: Int, CaseIterable {
         case home
@@ -361,10 +361,10 @@ extension MainTabBarController: UITabBarControllerDelegate {
         os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s: select %s", ((#file as NSString).lastPathComponent), #line, #function, viewController.debugDescription)
         defer {
             if let tab = Tab(rawValue: tabBarController.selectedIndex) {
-                currentTab = tab
+                currentTab.value = tab
             }
         }
-        guard currentTab.rawValue == tabBarController.selectedIndex,
+        guard currentTab.value.rawValue == tabBarController.selectedIndex,
               let navigationController = viewController as? UINavigationController,
               navigationController.viewControllers.count == 1,
               let scrollViewContainer = navigationController.topViewController as? ScrollViewContainer else {
@@ -535,7 +535,7 @@ extension MainTabBarController {
         let previousTab = Tab(rawValue: selectedIndex)
         selectedIndex = index
         if let tab = Tab(rawValue: index) {
-            currentTab = tab
+            currentTab.value = tab
         }
 
         if let previousTab = previousTab {

Mastodon/Scene/Root/RootSplitViewController.swift

@@ -7,9 +7,12 @@
 
 import os.log
 import UIKit
+import Combine
 
 final class RootSplitViewController: UISplitViewController, NeedsDependency {
     
+    var disposeBag = Set<AnyCancellable>()
+    
     weak var context: AppContext! { willSet { precondition(!isViewLoaded) } }
     weak var coordinator: SceneCoordinator! { willSet { precondition(!isViewLoaded) } }
     
@@ -22,6 +25,13 @@ final class RootSplitViewController: UISplitViewController, NeedsDependency {
         return sidebarViewController
     }()
         
+    var currentSupplementaryTab: MainTabBarController.Tab = .home
+    private(set) lazy var supplementaryViewControllers: [UIViewController] = {
+        return MainTabBarController.Tab.allCases.map { tab in
+            tab.viewController(context: context, coordinator: coordinator)
+        }
+    }()
+    
     private(set) lazy var mainTabBarController = MainTabBarController(context: context, coordinator: coordinator)
     
     init(context: AppContext, coordinator: SceneCoordinator) {
@@ -32,6 +42,7 @@ final class RootSplitViewController: UISplitViewController, NeedsDependency {
         primaryBackgroundStyle = .sidebar
         preferredDisplayMode = .oneBesideSecondary
         preferredSplitBehavior = .tile
+        delegate = self
         
         if #available(iOS 14.5, *) {
             displayModeButtonVisibility = .always
@@ -40,7 +51,7 @@ final class RootSplitViewController: UISplitViewController, NeedsDependency {
         }
         
         setViewController(sidebarViewController, for: .primary)
-        setViewController(mainTabBarController.viewControllers!.first, for: .supplementary)
+        setViewController(supplementaryViewControllers[0], for: .supplementary)
         setViewController(UIViewController(), for: .secondary)
         setViewController(mainTabBarController, for: .compact)
     }
@@ -61,6 +72,18 @@ extension RootSplitViewController {
         super.viewDidLoad()
         
         updateBehavior(size: view.frame.size)
+        
+        mainTabBarController.currentTab
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] tab in
+                guard let self = self else { return }
+                guard tab != self.currentSupplementaryTab else { return }
+                guard let index = MainTabBarController.Tab.allCases.firstIndex(of: tab) else { return }
+                self.currentSupplementaryTab = tab
+                self.setViewController(self.supplementaryViewControllers[index], for: .supplementary)
+                
+            }
+            .store(in: &disposeBag)
     }
     
     override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
@@ -86,16 +109,76 @@ extension RootSplitViewController {
 extension RootSplitViewController: SidebarViewControllerDelegate {
     func sidebarViewController(_ sidebarViewController: SidebarViewController, didSelectTab tab: MainTabBarController.Tab) {
         
-        // FIXME: remove hard code
+        guard let index = MainTabBarController.Tab.allCases.firstIndex(of: tab) else {
-        switch tab {
+            assertionFailure()
-        case .home:
+            return
-            setViewController(mainTabBarController._viewControllers[0], for: .supplementary)
+        }
-        case .search:
+        currentSupplementaryTab = tab
-            setViewController(mainTabBarController._viewControllers[1], for: .supplementary)
+        setViewController(supplementaryViewControllers[index], for: .supplementary)
-        case .notification:
+    }
-            setViewController(mainTabBarController._viewControllers[2], for: .supplementary)
+}
-        case .me:
+
-            setViewController(mainTabBarController._viewControllers[3], for: .supplementary)
+// MARK: - UISplitViewControllerDelegate
+extension RootSplitViewController: UISplitViewControllerDelegate {
+    
+    // .regular to .compact
+    // move navigation stack from .supplementary & .secondary to .compact
+    func splitViewController(
+        _ svc: UISplitViewController,
+        topColumnForCollapsingToProposedTopColumn proposedTopColumn: UISplitViewController.Column
+    ) -> UISplitViewController.Column {
+        switch proposedTopColumn {
+        case .compact:
+            guard let index = MainTabBarController.Tab.allCases.firstIndex(of: currentSupplementaryTab) else {
+                assertionFailure()
+                break
+            }
+            mainTabBarController.selectedIndex = index
+            mainTabBarController.currentTab.value = currentSupplementaryTab
+            
+            guard let navigationController = mainTabBarController.selectedViewController as? UINavigationController else { break }
+            navigationController.popToRootViewController(animated: false)
+            var viewControllers = navigationController.viewControllers      // init navigation stack with topMost
+
+            if let supplementaryNavigationController = viewController(for: .supplementary) as? UINavigationController {
+                // append supplementary
+                viewControllers.append(contentsOf: supplementaryNavigationController.popToRootViewController(animated: true) ?? [])
+            }
+            if let secondaryNavigationController = viewController(for: .secondary) as? UINavigationController {
+                // append secondary
+                viewControllers.append(contentsOf: secondaryNavigationController.popToRootViewController(animated: true) ?? [])
+            }
+            // set navigation stack
+            navigationController.setViewControllers(viewControllers, animated: false)
+            
+        default:
+            assertionFailure()
+        }
+
+        return proposedTopColumn
+    }
+    
+    // .compact to .regular
+    // restore navigation stack to .supplementary & .secondary
+    func splitViewController(
+        _ svc: UISplitViewController,
+        displayModeForExpandingToProposedDisplayMode proposedDisplayMode: UISplitViewController.DisplayMode
+    ) -> UISplitViewController.DisplayMode {
+        
+        return proposedDisplayMode
+    }
+    
+    func splitViewController(
+        _ splitViewController: UISplitViewController,
+        show vc: UIViewController,
+        sender: Any?
+    ) -> Bool {
+        if !splitViewController.isCollapsed {
+            // display in .secondary when expand
+            splitViewController.showDetailViewController(vc, sender: sender)
+            return true
+        } else {
+            return false
         }
     }
 }