Fix some app route navigation bugs. (#4415)

- Opening a notification would update the stack with an animated pop.
- Opening a permalink from the timeline wouldn't push the room as a child.

ElementX/Sources/FlowCoordinators/UserSessionFlowCoordinator.swift

@@ -157,20 +157,32 @@ class UserSessionFlowCoordinator: FlowCoordinatorProtocol {
              .roomDetails, .roomMemberDetails, .userProfile,
              .event, .eventOnRoomAlias, .childEvent, .childEventOnRoomAlias,
              .call, .genericCallLink, .share, .transferOwnership:
-            clearRoute(animated: animated) // Make sure the presented route is visible.
+            clearPresentedSheets(animated: animated) // Make sure the presented route is visible.
             chatsFlowCoordinator.handleAppRoute(appRoute, animated: animated)
-            navigationTabCoordinator.selectedTab = .chats
+            if navigationTabCoordinator.selectedTab != .chats {
+                navigationTabCoordinator.selectedTab = .chats
+            }
         }
     }
     
     func clearRoute(animated: Bool) {
+        clearPresentedSheets(animated: animated)
+        chatsFlowCoordinator.clearRoute(animated: animated)
+    }
+    
+    // Clearing routes is more complicated than it first seems. When passing routes
+    // to the chats flow we can't clear all routes as e.g. childRoom/childEvent etc
+    // expect to push into the existing stack. But we do need to hide any sheets that
+    // might cover up the presented route. BUT! We probably shouldn't dismiss onboarding
+    // or verification flows until they're complete… This needs more thought before we
+    // codify it all into the state machine.
+    private func clearPresentedSheets(animated: Bool) {
         switch stateMachine.state {
         case .initial, .tabBar:
             break
         case .settingsScreen:
             navigationTabCoordinator.setSheetCoordinator(nil, animated: animated)
         }
-        chatsFlowCoordinator.clearRoute(animated: animated)
     }
     
     func isDisplayingRoomScreen(withRoomID roomID: String) -> Bool {
@@ -258,7 +270,7 @@ class UserSessionFlowCoordinator: FlowCoordinatorProtocol {
     
     // MARK: - Onboarding
     
-    func attemptStartingOnboarding() {
+    private func attemptStartingOnboarding() {
         MXLog.info("Attempting to start onboarding")
         
         if onboardingFlowCoordinator.shouldStart {

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -5,7 +5,6 @@
 // Please see LICENSE files in the repository root for full details.
 //
 
-import Algorithms
 import Combine
 import Foundation
 import MatrixRustSDK

ElementX/Sources/Services/Room/RoomProxyProtocol.swift

@@ -5,6 +5,7 @@
 // Please see LICENSE files in the repository root for full details.
 //
 
+import Algorithms
 import Combine
 import Foundation
 import MatrixRustSDK

UnitTests/Sources/UserSessionFlowCoordinatorTests.swift

@@ -68,6 +68,32 @@ class UserSessionFlowCoordinatorTests: XCTestCase {
         XCTAssertNotNil(detailCoordinator)
     }
     
+    func testRoomPresentationClearsSettings() async throws {
+        try await process(route: .settings, expectedUserSessionState: .settingsScreen)
+        XCTAssertTrue((tabCoordinator?.sheetCoordinator as? NavigationStackCoordinator)?.rootCoordinator is SettingsScreenCoordinator)
+        XCTAssertNil(detailCoordinator)
+        
+        try await process(route: .room(roomID: "1", via: []), expectedChatsState: .roomList(roomListSelectedRoomID: "1"))
+        XCTAssertNil((tabCoordinator?.sheetCoordinator))
+        XCTAssertTrue(detailNavigationStack?.rootCoordinator is RoomScreenCoordinator)
+        XCTAssertNotNil(detailCoordinator)
+    }
+    
+    func testChildRoomPresentation() async throws {
+        try await process(route: .room(roomID: "1", via: []), expectedChatsState: .roomList(roomListSelectedRoomID: "1"))
+        let detailNavigationStack = try XCTUnwrap(detailNavigationStack, "There must be a navigation stack.")
+        XCTAssertTrue(detailNavigationStack.rootCoordinator is RoomScreenCoordinator)
+        XCTAssertNotNil(detailCoordinator)
+        
+        let deferred = deferFulfillment(detailNavigationStack.observe(\.stackCoordinators.count)) { $0 == 1 }
+        try await process(route: .childRoom(roomID: "2", via: []))
+        try await deferred.fulfill()
+        XCTAssertTrue(detailNavigationStack.rootCoordinator is RoomScreenCoordinator)
+        XCTAssertNotNil(detailCoordinator)
+        XCTAssertEqual(detailNavigationStack.stackCoordinators.count, 1)
+        XCTAssertTrue(detailNavigationStack.stackCoordinators.first is RoomScreenCoordinator)
+    }
+    
     func testShareMediaRouteWithoutRoom() async throws {
         try await process(route: .settings, expectedUserSessionState: .settingsScreen)
         XCTAssertTrue((tabCoordinator?.sheetCoordinator as? NavigationStackCoordinator)?.rootCoordinator is SettingsScreenCoordinator)