fix: exit lnurl screens whose payment data is gone

Bitkit/ViewModels/AppViewModel.swift

@@ -359,7 +359,11 @@ class AppViewModel: ObservableObject {
     private let navigationViewModel: NavigationViewModel
     private let scanPaymentOperations: ScanPaymentOperations
     private let usdtBalance: () -> UInt64?
-    private var scannedDataHandlingId: UUID?
+    @Published private var scannedDataHandlingId: UUID?
+    var isHandlingScannedData: Bool {
+        scannedDataHandlingId != nil
+    }
+
     private var manualEntryValidationSequence: UInt64 = 0
 
     // Combine infrastructure for debounced validation

Bitkit/Views/Wallets/Send/SendSheet.swift

@@ -179,6 +179,15 @@ struct SendSheet: View {
         config.preparation != nil && incomingPaymentRequest == nil
     }
 
+    private var isMissingLnurlPayData: Bool {
+        guard app.lnurlPayData == nil, !app.isHandlingScannedData, !isSubmittingPayment else { return false }
+        return Self.isLnurlPayRoute(navigationPath.last ?? currentRoot)
+    }
+
+    private static func isLnurlPayRoute(_ route: SendRoute) -> Bool {
+        route == .lnurlPayAmount || route == .lnurlPayConfirm
+    }
+
     private var shouldDismissUnavailableRequest: Bool {
         guard let request = incomingPaymentRequest else { return false }
         return Self.shouldDismissUnavailableRequest(
@@ -285,6 +294,10 @@ struct SendSheet: View {
             guard shouldDismiss else { return }
             sheets.hideSheetIfActive(isEmbedded ? .subscription : .send, reason: "Incoming payment request is no longer available")
         }
+        .onChange(of: isMissingLnurlPayData, initial: true) { _, isMissing in
+            guard isMissing, isCurrentPresentation else { return }
+            exitMissingLnurlPayment()
+        }
         .onChange(of: shouldShowSyncOverlay, initial: true) { _, isShowing in
             Logger.debug("shouldShowSyncOverlay: \(isShowing) (node: \(wallet.nodeLifecycleState))", context: "SendSheet")
         }
@@ -1249,6 +1262,14 @@ struct SendSheet: View {
         navigationPath = [route]
     }
 
+    private func exitMissingLnurlPayment() {
+        if !Self.isLnurlPayRoute(currentRoot), let index = navigationPath.firstIndex(where: Self.isLnurlPayRoute) {
+            navigationPath.removeSubrange(index...)
+        } else {
+            sheets.hideSheetIfActive(isEmbedded ? .subscription : .send, reason: "LNURL payment data is no longer available")
+        }
+    }
+
     private func replaceRootRoute(with route: SendRoute) {
         rootOverride = nil
         rootRoute = route

BitkitTests/SendSheetLifecycleTests.swift

@@ -80,11 +80,40 @@ final class SendSheetLifecycleTests: XCTestCase {
         XCTAssertNil(app.lnurlPayData, "Ending the presentation must still clean up")
     }
 
-    func testEmbeddedSendExitCleansStateWhileSubscriptionRemainsActive() async throws {
-        let (app, sheets, prompt, window) = makeHost(isEmbedded: true)
+    func testMissingLnurlDataClosesItsPresentation() async throws {
+        let (app, sheets, _, window) = makeHost()
         defer { window.isHidden = true; window.rootViewController = nil }
         app.lnurlPayData = makeLnurlData()
         app.selectedWalletToPayFrom = .lightning
+        sheets.showSheet(.send, data: SendConfig(view: .lnurlPayConfirm))
+        try await Task.sleep(for: .seconds(1))
+        XCTAssertEqual(sheets.activeSheetConfiguration?.id, .send)
+        app.lnurlPayData = nil
+        try await Task.sleep(for: .milliseconds(500))
+        XCTAssertNil(sheets.activeSheetConfiguration, "A confirmation without LNURL data must close instead of staying blank")
+    }
+
+    func testMissingLnurlDataClosesAmountRootedPresentation() async throws {
+        let (app, sheets, _, window) = makeHost()
+        defer { window.isHidden = true; window.rootViewController = nil }
+        app.lnurlPayData = LnurlPayData(
+            uri: "https://example.com/variable", callback: "https://example.com/callback",
+            minSendable: 149_500, maxSendable: 200_999,
+            metadataStr: "[]", commentAllowed: 12, allowsNostr: false, nostrPubkey: nil
+        )
+        app.selectedWalletToPayFrom = .lightning
+        sheets.showSheet(.send, data: SendConfig(view: .lnurlPayAmount))
+        try await Task.sleep(for: .seconds(1))
+        XCTAssertEqual(sheets.activeSheetConfiguration?.id, .send)
+        app.lnurlPayData = nil
+        try await Task.sleep(for: .milliseconds(500))
+        XCTAssertNil(sheets.activeSheetConfiguration, "An amount root without LNURL data must close, not stay unusable")
+    }
+
+    func testEmbeddedSendExitCleansStateWhileSubscriptionRemainsActive() async throws {
+        // Subscriptions route embedded Send to LNURL confirmation only once its data is set.
+        let (app, sheets, prompt, window) = makeHost(isEmbedded: true, lnurlPayData: makeLnurlData())
+        defer { window.isHidden = true; window.rootViewController = nil }
         try await Task.sleep(for: .seconds(1))
         let presentationID = try XCTUnwrap(sheets.activeSheetConfiguration?.presentationID)
         XCTAssertEqual(app.lnurlPayData?.minSendable, 222_222)
@@ -101,10 +130,17 @@ final class SendSheetLifecycleTests: XCTestCase {
                      commentAllowed: nil, allowsNostr: false, nostrPubkey: nil)
     }
 
-    private func makeHost(isEmbedded: Bool = false) -> (AppViewModel, SheetViewModel, ScanPromptState, UIWindow) {
+    private func makeHost(
+        isEmbedded: Bool = false,
+        lnurlPayData: LnurlPayData? = nil
+    ) -> (AppViewModel, SheetViewModel, ScanPromptState, UIWindow) {
         snapshotAppDefaultsDomain()
         snapshotAppGroupDefaults("home_screen_display_currency_code_v1", "home_screen_display_currency_symbol_v1")
         let app = AppViewModel()
+        if let lnurlPayData {
+            app.lnurlPayData = lnurlPayData
+            app.selectedWalletToPayFrom = .lightning
+        }
         let wallet = WalletViewModel()
         wallet.nodeLifecycleState = .running
         let sheets = SheetViewModel()