fix: various fixes

Bitkit/Managers/ToastWindowManager.swift

@@ -35,13 +35,22 @@ class ToastWindowManager: ObservableObject {
     }
 
     func showToast(_ toast: Toast) {
+        // Ensure window is set up before showing toast
+        ensureWindowExists()
+
+        // If window still doesn't exist after trying to set it up, log and return
+        guard let window = toastWindow else {
+            Logger.error("ToastWindowManager: Cannot show toast - window not available")
+            return
+        }
+
         // Dismiss any existing toast first
         cancelAutoHide()
-        toastWindow?.hasToast = false
-        toastWindow?.toastFrame = .zero
+        window.hasToast = false
+        window.toastFrame = .zero
 
         // Update window's toast state for hit testing
-        toastWindow?.hasToast = true
+        window.hasToast = true
 
         // Show the toast with animation
         withAnimation(.easeInOut(duration: 0.4)) {
@@ -68,7 +77,7 @@ class ToastWindowManager: ObservableObject {
     }
 
     func pauseAutoHide() {
-        guard autoHideStartTime != nil else { return } // Already paused or no auto-hide
+        guard autoHideStartTime != nil else { return } // No active auto-hide to pause
         cancelAutoHide()
 
         // Calculate remaining time
@@ -124,11 +133,32 @@ class ToastWindowManager: ObservableObject {
         autoHideDuration = 0
     }
 
+    private func ensureWindowExists() {
+        // Check if window already exists and is still valid
+        if let existingWindow = toastWindow,
+           existingWindow.windowScene != nil,
+           !existingWindow.isHidden
+        {
+            return
+        }
+
+        // Window doesn't exist or is invalid, try to set it up
+        setupToastWindow()
+    }
+
     private func setupToastWindow() {
-        guard let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene else {
+        // Try to find an active window scene
+        guard let windowScene = findActiveWindowScene() else {
+            Logger.warn("ToastWindowManager: No active window scene available")
             return
         }
 
+        // Clean up old window if it exists
+        if let oldWindow = toastWindow {
+            oldWindow.isHidden = true
+            oldWindow.rootViewController = nil
+        }
+
         let window = PassThroughWindow(windowScene: windowScene)
         window.windowLevel = UIWindow.Level.alert + 1 // Above alerts and sheets
         window.backgroundColor = .clear
@@ -143,6 +173,20 @@ class ToastWindowManager: ObservableObject {
         toastWindow = window
         toastHostingController = hostingController
     }
+
+    private func findActiveWindowScene() -> UIWindowScene? {
+        // Try to find an active window scene from connected scenes
+        for scene in UIApplication.shared.connectedScenes {
+            if let windowScene = scene as? UIWindowScene,
+               windowScene.activationState == .foregroundActive || windowScene.activationState == .foregroundInactive
+            {
+                return windowScene
+            }
+        }
+
+        // Fallback to any window scene if no active one found
+        return UIApplication.shared.connectedScenes.first as? UIWindowScene
+    }
 }
 
 // Custom window that only intercepts touches on interactive elements

Bitkit/ViewModels/AmountInputViewModel.swift

@@ -96,8 +96,12 @@ class AmountInputViewModel: ObservableObject {
         amountSats = newAmountSats
         displayText = formatDisplayTextFromAmount(newAmountSats, currency: currency)
         // Update raw input text based on the formatted display
+        // Remove formatting separators (spaces for modern Bitcoin, commas for fiat)
         if currency.primaryDisplay == .fiat {
             rawInputText = displayText.replacingOccurrences(of: ",", with: "")
+        } else if currency.displayUnit == .modern {
+            // Modern Bitcoin uses spaces as grouping separators
+            rawInputText = displayText.replacingOccurrences(of: " ", with: "")
         } else {
             rawInputText = displayText
         }
@@ -115,8 +119,12 @@ class AmountInputViewModel: ObservableObject {
         if amountSats > 0 {
             displayText = formatDisplayTextFromAmount(amountSats, currency: currency)
             // Update raw input text based on the formatted display
+            // Remove formatting separators (spaces for modern Bitcoin, commas for fiat)
             if currency.primaryDisplay == .fiat {
                 rawInputText = displayText.replacingOccurrences(of: ",", with: "")
+            } else if currency.displayUnit == .modern {
+                // Modern Bitcoin uses spaces as grouping separators
+                rawInputText = displayText.replacingOccurrences(of: " ", with: "")
             } else {
                 rawInputText = displayText
             }
@@ -135,8 +143,14 @@ class AmountInputViewModel: ObservableObject {
                 // First convert fiat to sats, then format for Bitcoin display
                 let cleanFiat = currentRawInput.replacingOccurrences(of: ",", with: "")
                 if let fiatValue = Double(cleanFiat), let sats = currency.convert(fiatAmount: fiatValue) {
-                    rawInputText = formatBitcoinFromSats(sats, isModern: currency.displayUnit == .modern)
-                    displayText = rawInputText
+                    let formatted = formatBitcoinFromSats(sats, isModern: currency.displayUnit == .modern)
+                    displayText = formatted
+                    // Remove spaces from rawInputText for modern Bitcoin
+                    if currency.displayUnit == .modern {
+                        rawInputText = formatted.replacingOccurrences(of: " ", with: "")
+                    } else {
+                        rawInputText = formatted
+                    }
                 }
             }
         }

Bitkit/Views/Settings/DevSettingsView.swift

@@ -102,6 +102,12 @@ struct DevSettingsView: View {
                         SettingsListLabel(title: "Test Push Notification", rightIcon: nil)
                     }
 
+                    Button {
+                        fatalError("Simulate Crash")
+                    } label: {
+                        SettingsListLabel(title: "Simulate Crash", rightIcon: nil)
+                    }
+
                     Button {
                         Task {
                             do {

Bitkit/Views/Wallets/Send/SendAmountView.swift

@@ -174,6 +174,14 @@ struct SendAmountView: View {
                 maxSendableAmount = nil
             }
         }
+        .onChange(of: wallet.selectedFeeRateSatsPerVByte) { _ in
+            // Recalculate max sendable amount when fee rate becomes available or changes
+            if app.selectedWalletToPayFrom == .onchain {
+                Task {
+                    await calculateMaxSendableAmount()
+                }
+            }
+        }
     }
 
     private func onContinue() async {
@@ -258,8 +266,8 @@ struct SendAmountView: View {
         } catch {
             Logger.error("Failed to calculate max sendable amount: \(error)")
             await MainActor.run {
-                // Fall back to total balance if calculation fails
-                maxSendableAmount = UInt64(wallet.spendableOnchainBalanceSats)
+                // Keep as nil on error - availableAmount will fall back to total balance
+                maxSendableAmount = nil
             }
         }
     }

BitkitTests/NumberPadTests.swift

@@ -179,6 +179,33 @@ final class NumberPadTests: XCTestCase {
         XCTAssertEqual(viewModel.amountSats, 0)
     }
 
+    func testDeleteAfterMaxAmountModernBitcoin() {
+        let viewModel = AmountInputViewModel()
+        let currency = mockCurrency(primaryDisplay: .bitcoin, displayUnit: .modern)
+
+        // Set max amount using updateFromSats (simulates tapping max button)
+        // This creates formatted text with spaces (e.g., "100 000 000")
+        viewModel.updateFromSats(100_000_000, currency: currency)
+        XCTAssertEqual(viewModel.displayText, "100 000 000")
+        XCTAssertEqual(viewModel.amountSats, 100_000_000)
+
+        // Delete should remove digits, not spaces
+        // After first delete, should be "10 000 000" (one digit removed)
+        viewModel.handleNumberPadInput("delete", currency: currency)
+        XCTAssertEqual(viewModel.displayText, "10 000 000")
+        XCTAssertEqual(viewModel.amountSats, 10_000_000)
+
+        // Delete again
+        viewModel.handleNumberPadInput("delete", currency: currency)
+        XCTAssertEqual(viewModel.displayText, "1 000 000")
+        XCTAssertEqual(viewModel.amountSats, 1_000_000)
+
+        // Delete again
+        viewModel.handleNumberPadInput("delete", currency: currency)
+        XCTAssertEqual(viewModel.displayText, "100 000")
+        XCTAssertEqual(viewModel.amountSats, 100_000)
+    }
+
     // MARK: - Leading Zero Tests
 
     func testLeadingZeroBehavior() {