Move tracking unsaved changes into coordinator

ios/MullvadVPN.xcodeproj/project.pbxproj

@@ -540,7 +540,7 @@
 		7A6F2FAB2AFD3097006D0856 /* CustomDNSCellFactory.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A6F2FAA2AFD3097006D0856 /* CustomDNSCellFactory.swift */; };
 		7A6F2FAD2AFD3DA7006D0856 /* CustomDNSViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A6F2FAC2AFD3DA7006D0856 /* CustomDNSViewController.swift */; };
 		7A6F2FAF2AFE36E7006D0856 /* VPNSettingsInfoButtonItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A6F2FAE2AFE36E7006D0856 /* VPNSettingsInfoButtonItem.swift */; };
-		7A7907332BC0280A00B61F81 /* InterceptibleNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A7907322BC0280A00B61F81 /* InterceptibleNavigationController.swift */; };
+		7A7907332BC0280A00B61F81 /* InterceptableNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A7907322BC0280A00B61F81 /* InterceptableNavigationController.swift */; };
 		7A7AD28D29DC677800480EF1 /* FirstTimeLaunch.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A7AD28C29DC677800480EF1 /* FirstTimeLaunch.swift */; };
 		7A818F1F29F0305800C7F0F4 /* RootConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A818F1E29F0305800C7F0F4 /* RootConfiguration.swift */; };
 		7A83A0C62B29A750008B5CE7 /* APIAccessMethodsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7A83A0C52B29A750008B5CE7 /* APIAccessMethodsTests.swift */; };
@@ -1806,7 +1806,7 @@
 		7A6F2FAA2AFD3097006D0856 /* CustomDNSCellFactory.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CustomDNSCellFactory.swift; sourceTree = "<group>"; };
 		7A6F2FAC2AFD3DA7006D0856 /* CustomDNSViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CustomDNSViewController.swift; sourceTree = "<group>"; };
 		7A6F2FAE2AFE36E7006D0856 /* VPNSettingsInfoButtonItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VPNSettingsInfoButtonItem.swift; sourceTree = "<group>"; };
-		7A7907322BC0280A00B61F81 /* InterceptibleNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InterceptibleNavigationController.swift; sourceTree = "<group>"; };
+		7A7907322BC0280A00B61F81 /* InterceptableNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InterceptableNavigationController.swift; sourceTree = "<group>"; };
 		7A7AD28C29DC677800480EF1 /* FirstTimeLaunch.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FirstTimeLaunch.swift; sourceTree = "<group>"; };
 		7A818F1E29F0305800C7F0F4 /* RootConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RootConfiguration.swift; sourceTree = "<group>"; };
 		7A83A0C52B29A750008B5CE7 /* APIAccessMethodsTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = APIAccessMethodsTests.swift; sourceTree = "<group>"; };
@@ -2696,7 +2696,7 @@
 				58138E60294871C600684F0C /* DeviceDataThrottling.swift */,
 				7A7AD28C29DC677800480EF1 /* FirstTimeLaunch.swift */,
 				582AE30F2440A6CA00E6733A /* InputTextFormatter.swift */,
-				7A7907322BC0280A00B61F81 /* InterceptibleNavigationController.swift */,
+				7A7907322BC0280A00B61F81 /* InterceptableNavigationController.swift */,
 				58DFF7D12B0256A300F864E0 /* MarkdownStylingOptions.swift */,
 				58CC40EE24A601900019D96E /* ObserverList.swift */,
 			);
@@ -5466,7 +5466,7 @@
 				7A42DEC92A05164100B209BE /* SettingsInputCell.swift in Sources */,
 				5803B4B22940A48700C23744 /* TunnelStore.swift in Sources */,
 				586A950F29012BEE007BAF2B /* AddressCacheTracker.swift in Sources */,
-				7A7907332BC0280A00B61F81 /* InterceptibleNavigationController.swift in Sources */,
+				7A7907332BC0280A00B61F81 /* InterceptableNavigationController.swift in Sources */,
 				F02F41A02B9723AF00625A4F /* AddLocationsViewController.swift in Sources */,
 				587B753D2666468F00DEF7E9 /* NotificationController.swift in Sources */,
 			);

ios/MullvadVPN/Classes/InterceptibleNavigationController.swift → ios/MullvadVPN/Classes/InterceptableNavigationController.swift

@@ -1,5 +1,5 @@
 //
-//  InterceptibleNavigationController.swift
+//  InterceptableNavigationController.swift
 //  MullvadVPN
 //
 //  Created by Jon Petersson on 2024-04-05.
@@ -8,12 +8,13 @@
 
 import UIKit
 
-class InterceptibleNavigationController: CustomNavigationController {
+class InterceptableNavigationController: CustomNavigationController {
     var shouldPopViewController: ((UIViewController) -> Bool)?
     var shouldPopToViewController: ((UIViewController) -> Bool)?
 
     // Called when popping the topmost view controller in the stack, eg. by pressing a navigation
     // bar back button.
+    @discardableResult
     override func popViewController(animated: Bool) -> UIViewController? {
         guard let viewController = viewControllers.last else { return nil }
 
@@ -26,6 +27,7 @@ class InterceptibleNavigationController: CustomNavigationController {
 
     // Called when popping to a specific view controller, eg. by long pressing a navigation bar
     // back button (revealing a navigation menu) and selecting a destination view controller.
+    @discardableResult
     override func popToViewController(_ viewController: UIViewController, animated: Bool) -> [UIViewController]? {
         if shouldPopToViewController?(viewController) ?? true {
             return super.popToViewController(viewController, animated: animated)

ios/MullvadVPN/Coordinators/CustomLists/CustomListViewController.swift

@@ -31,7 +31,7 @@ class CustomListViewController: UIViewController {
         return interactor.fetchAll().first(where: { $0.id == subject.value.id })
     }
 
-    private var hasUnsavedChanges: Bool {
+    var hasUnsavedChanges: Bool {
         persistedCustomList != subject.value.customList
     }
 
@@ -83,12 +83,12 @@ class CustomListViewController: UIViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
 
+        navigationItem.rightBarButtonItem = saveBarButton
         view.directionalLayoutMargins = UIMetrics.contentLayoutMargins
         view.backgroundColor = .secondaryColor
         isModalInPresentation = true
 
         addSubviews()
-        configureNavigationItem()
         configureDataSource()
         configureTableView()
 
@@ -98,39 +98,6 @@ class CustomListViewController: UIViewController {
         }.store(in: &cancellables)
     }
 
-    private func configureNavigationItem() {
-        if let navigationController = navigationController as? InterceptibleNavigationController {
-            interceptNavigation(navigationController)
-        }
-
-        navigationController?.interactivePopGestureRecognizer?.delegate = self
-        navigationItem.rightBarButtonItem = saveBarButton
-    }
-
-    private func interceptNavigation(_ navigationController: InterceptibleNavigationController) {
-        navigationController.shouldPopViewController = { [weak self] viewController in
-            guard
-                let self,
-                viewController is Self,
-                hasUnsavedChanges
-            else { return true }
-
-            self.onUnsavedChanges()
-            return false
-        }
-
-        navigationController.shouldPopToViewController = { [weak self] viewController in
-            guard
-                let self,
-                viewController is ListCustomListViewController,
-                hasUnsavedChanges
-            else { return true }
-
-            self.onUnsavedChanges()
-            return false
-        }
-    }
-
     private func configureTableView() {
         tableView.delegate = dataSourceConfiguration
         tableView.backgroundColor = .secondaryColor
@@ -232,68 +199,4 @@ class CustomListViewController: UIViewController {
 
         alertPresenter.showAlert(presentation: presentation, animated: true)
     }
-
-    @objc private func onUnsavedChanges() {
-        let message = NSMutableAttributedString(
-            markdownString: NSLocalizedString(
-                "CUSTOM_LISTS_UNSAVED_CHANGES_PROMPT",
-                tableName: "CustomLists",
-                value: "You have unsaved changes.",
-                comment: ""
-            ),
-            options: MarkdownStylingOptions(font: .preferredFont(forTextStyle: .body))
-        )
-
-        let presentation = AlertPresentation(
-            id: "api-custom-lists-unsaved-changes-alert",
-            icon: .alert,
-            attributedMessage: message,
-            buttons: [
-                AlertAction(
-                    title: NSLocalizedString(
-                        "CUSTOM_LISTS_DISCARD_CHANGES_BUTTON",
-                        tableName: "CustomLists",
-                        value: "Discard changes",
-                        comment: ""
-                    ),
-                    style: .destructive,
-                    handler: {
-                        // Reset subject/view model to no longer having unsaved changes.
-                        if let persistedCustomList = self.persistedCustomList {
-                            self.subject.value.update(with: persistedCustomList)
-                        }
-                        self.delegate?.customListDidSave(self.subject.value.customList)
-                    }
-                ),
-                AlertAction(
-                    title: NSLocalizedString(
-                        "CUSTOM_LISTS_BACK_TO_EDITING_BUTTON",
-                        tableName: "CustomLists",
-                        value: "Back to editing",
-                        comment: ""
-                    ),
-                    style: .default
-                ),
-            ]
-        )
-
-        alertPresenter.showAlert(presentation: presentation, animated: true)
-    }
-}
-
-extension CustomListViewController: UIGestureRecognizerDelegate {
-    // For some reason, intercepting `popViewController(animated: Bool)` in `InterceptibleNavigationController`
-    // by SWIPING back leads to weird behaviour where subsequent navigation seem to happen systemwise but not
-    // UI-wise. This leads to the UI freezing up, and the only remedy is to restart the app.
-    //
-    // To get around this issue we can intercept the back swipe gesture and manually perform the transition
-    // instead, thereby bypassing the inner mechanisms that seem to go out of sync.
-    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
-        guard gestureRecognizer == navigationController?.interactivePopGestureRecognizer else {
-            return true
-        }
-
-        navigationController?.popViewController(animated: true)
-        return false
-    }
 }

ios/MullvadVPN/Coordinators/CustomLists/EditCustomListCoordinator.swift

@@ -21,12 +21,16 @@ class EditCustomListCoordinator: Coordinator, Presentable, Presenting {
     let customList: CustomList
     let nodes: [LocationNode]
     let subject: CurrentValueSubject<CustomListViewModel, Never>
+    private lazy var alertPresenter: AlertPresenter = {
+        AlertPresenter(context: self)
+    }()
 
     var presentedViewController: UIViewController {
         navigationController
     }
 
     var didFinish: ((EditCustomListCoordinator, FinishAction, CustomList) -> Void)?
+    var didCancel: ((EditCustomListCoordinator) -> Void)?
 
     init(
         navigationController: UINavigationController,
@@ -50,7 +54,7 @@ class EditCustomListCoordinator: Coordinator, Presentable, Presenting {
         let controller = CustomListViewController(
             interactor: customListInteractor,
             subject: subject,
-            alertPresenter: AlertPresenter(context: self)
+            alertPresenter: alertPresenter
         )
         controller.delegate = self
 
@@ -61,7 +65,76 @@ class EditCustomListCoordinator: Coordinator, Presentable, Presenting {
             comment: ""
         )
 
+        navigationController.interactivePopGestureRecognizer?.delegate = self
         navigationController.pushViewController(controller, animated: true)
+
+        guard let interceptableNavigationController = navigationController as? InterceptableNavigationController else {
+            return
+        }
+
+        interceptableNavigationController.shouldPopViewController = { [weak self] viewController in
+            guard
+                let self,
+                let customListViewController = viewController as? CustomListViewController,
+                customListViewController.hasUnsavedChanges
+            else { return true }
+            presentUnsavedChangesDialog()
+            return false
+        }
+
+        interceptableNavigationController.shouldPopToViewController = { [weak self] viewController in
+            guard
+                let self,
+                let customListViewController = viewController as? CustomListViewController,
+                customListViewController.hasUnsavedChanges
+            else { return true }
+
+            presentUnsavedChangesDialog()
+            return false
+        }
+    }
+
+    private func presentUnsavedChangesDialog() {
+        let message = NSMutableAttributedString(
+            markdownString: NSLocalizedString(
+                "CUSTOM_LISTS_UNSAVED_CHANGES_PROMPT",
+                tableName: "CustomLists",
+                value: "You have unsaved changes.",
+                comment: ""
+            ),
+            options: MarkdownStylingOptions(font: .preferredFont(forTextStyle: .body))
+        )
+
+        let presentation = AlertPresentation(
+            id: "api-custom-lists-unsaved-changes-alert",
+            icon: .alert,
+            attributedMessage: message,
+            buttons: [
+                AlertAction(
+                    title: NSLocalizedString(
+                        "CUSTOM_LISTS_DISCARD_CHANGES_BUTTON",
+                        tableName: "CustomLists",
+                        value: "Discard changes",
+                        comment: ""
+                    ),
+                    style: .destructive,
+                    handler: {
+                        self.didCancel?(self)
+                    }
+                ),
+                AlertAction(
+                    title: NSLocalizedString(
+                        "CUSTOM_LISTS_BACK_TO_EDITING_BUTTON",
+                        tableName: "CustomLists",
+                        value: "Back to editing",
+                        comment: ""
+                    ),
+                    style: .default
+                ),
+            ]
+        )
+
+        alertPresenter.showAlert(presentation: presentation, animated: true)
     }
 }
 
@@ -90,3 +163,19 @@ extension EditCustomListCoordinator: CustomListViewControllerDelegate {
         addChild(coordinator)
     }
 }
+
+extension EditCustomListCoordinator: UIGestureRecognizerDelegate {
+    // For some reason, intercepting `popViewController(animated: Bool)` in `InterceptibleNavigationController`
+    // by SWIPING back leads to weird behaviour where subsequent navigation seem to happen systemwise but not
+    // UI-wise. This leads to the UI freezing up, and the only remedy is to restart the app.
+    //
+    // To get around this issue we can intercept the back swipe gesture and manually perform the transition
+    // instead, thereby bypassing the inner mechanisms that seem to go out of sync.
+    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
+        guard gestureRecognizer == navigationController.interactivePopGestureRecognizer else {
+            return true
+        }
+        navigationController.popViewController(animated: true)
+        return false
+    }
+}

ios/MullvadVPN/Coordinators/CustomLists/ListCustomListCoordinator.swift

@@ -65,6 +65,12 @@ class ListCustomListCoordinator: Coordinator, Presentable, Presenting {
             self.updateRelayConstraints(for: action, in: list)
         }
 
+        coordinator.didCancel = { [weak self] editCustomListCoordinator in
+            guard let self else { return }
+            popToList()
+            editCustomListCoordinator.removeFromParent()
+        }
+
         coordinator.start()
         addChild(coordinator)
     }

ios/MullvadVPN/Coordinators/LocationCoordinator.swift

@@ -147,7 +147,7 @@ class LocationCoordinator: Coordinator, Presentable, Presenting {
 
     private func showEditCustomLists(nodes: [LocationNode]) {
         let coordinator = ListCustomListCoordinator(
-            navigationController: InterceptibleNavigationController(),
+            navigationController: InterceptableNavigationController(),
             interactor: CustomListInteractor(repository: customListRepository),
             tunnelManager: tunnelManager,
             nodes: nodes