Merge pull request 'fix: prevent DXSmart disconnect race killing Write Config screen' (#37) from schwifty/fix-dxsmart-disconnect-race into main

After DXSmart auth completes, the beacon often drops BLE connection
due to aggressive timeouts. The disconnect handler was treating this
as a failure, stomping the .connected state before the user could see
the "Write Config" button.

Changes:
- Ignore BLE disconnects during .connected state for DXSmart beacons
  (the LED keeps flashing regardless of BLE connection)
- Auto-reconnect in writeConfigToConnectedBeacon() if BLE dropped
  while waiting for user confirmation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

PayfritBeacon/Provisioners/KBeaconProvisioner.swift

@@ -47,6 +47,9 @@ final class KBeaconProvisioner: NSObject, BeaconProvisioner {
     var diagnosticLog: ProvisionLog?
     var bleManager: BLEManager?
 
+    /// Status callback — provisioner reports what phase it's in so UI can update
+    var onStatusUpdate: ((String) -> Void)?
+
     // MARK: - Init
 
     init(peripheral: CBPeripheral, centralManager: CBCentralManager) {
@@ -62,14 +65,27 @@ final class KBeaconProvisioner: NSObject, BeaconProvisioner {
         // Connect with retry
         for attempt in 1...GATTConstants.maxRetries {
             do {
+                let attemptLabel = GATTConstants.maxRetries > 1 ? " (attempt \(attempt)/\(GATTConstants.maxRetries))" : ""
+                await MainActor.run { onStatusUpdate?("Connecting to beacon…\(attemptLabel)") }
+                await diagnosticLog?.log("connect", "Attempt \(attempt)/\(GATTConstants.maxRetries)")
                 try await connectOnce()
+
+                await MainActor.run { onStatusUpdate?("Discovering services…") }
+                await diagnosticLog?.log("connect", "Connected — discovering services…")
                 try await discoverServices()
+                await diagnosticLog?.log("connect", "Services found — write:\(writeChar != nil) notify:\(notifyChar != nil)")
+
+                await MainActor.run { onStatusUpdate?("Authenticating…") }
+                await diagnosticLog?.log("auth", "Trying \(Self.passwords.count) passwords…")
                 try await authenticate()
+                await diagnosticLog?.log("auth", "Auth success")
                 isConnected = true
                 return
             } catch {
+                await diagnosticLog?.log("connect", "Attempt \(attempt) failed: \(error.localizedDescription)", isError: true)
                 disconnect()
                 if attempt < GATTConstants.maxRetries {
+                    await MainActor.run { onStatusUpdate?("Retrying… (\(attempt)/\(GATTConstants.maxRetries))") }
                     try await Task.sleep(nanoseconds: UInt64(GATTConstants.retryDelay * 1_000_000_000))
                 } else {
                     throw error
@@ -111,17 +127,23 @@ final class KBeaconProvisioner: NSObject, BeaconProvisioner {
         params.append(UInt8(config.advInterval & 0xFF))
 
         // Send CMD_WRITE_PARAMS
+        await MainActor.run { onStatusUpdate?("Writing beacon parameters…") }
+        await diagnosticLog?.log("write", "Sending CMD_WRITE_PARAMS (\(params.count) bytes)…")
         let writeCmd = Data([CMD.writeParams.rawValue]) + params
         let writeResp = try await sendCommand(writeCmd)
         guard writeResp.first == CMD.writeParams.rawValue else {
             throw ProvisionError.writeFailed("Unexpected write response")
         }
+        await diagnosticLog?.log("write", "Params written OK — saving to flash…")
 
         // Send CMD_SAVE to flash
+        await MainActor.run { onStatusUpdate?("Saving to flash…") }
         let saveResp = try await sendCommand(Data([CMD.save.rawValue]))
         guard saveResp.first == CMD.save.rawValue else {
             throw ProvisionError.saveFailed
         }
+        await MainActor.run { onStatusUpdate?("Config saved ✓") }
+        await diagnosticLog?.log("write", "Save confirmed")
     }
 
     func disconnect() {
@@ -180,14 +202,20 @@ final class KBeaconProvisioner: NSObject, BeaconProvisioner {
     }
 
     private func authenticate() async throws {
-        for password in Self.passwords {
+        for (index, password) in Self.passwords.enumerated() {
+            let passwordLabel = String(data: password.prefix(6), encoding: .utf8) ?? "binary"
+            await MainActor.run { onStatusUpdate?("Authenticating… (\(index + 1)/\(Self.passwords.count))") }
+            await diagnosticLog?.log("auth", "Trying password \(index + 1)/\(Self.passwords.count): \(passwordLabel)…")
             let cmd = Data([CMD.auth.rawValue]) + password
             do {
                 let resp = try await sendCommand(cmd)
                 if resp.first == CMD.auth.rawValue && resp.count > 1 && resp[1] == 0x00 {
+                    await MainActor.run { onStatusUpdate?("Authenticated ✓") }
                     return // Auth success
                 }
+                await diagnosticLog?.log("auth", "Password \(index + 1) rejected (response: \(resp.map { String(format: "%02X", $0) }.joined()))")
             } catch {
+                await diagnosticLog?.log("auth", "Password \(index + 1) timeout: \(error.localizedDescription)")
                 continue
             }
         }

PayfritBeacon/Views/ScanView.swift

@@ -619,6 +619,10 @@ struct ScanView: View {
                 dxProvisioner.onStatusUpdate = { [weak self] status in
                     self?.statusMessage = status
                 }
+            } else if let kbProvisioner = provisioner as? KBeaconProvisioner {
+                kbProvisioner.onStatusUpdate = { [weak self] status in
+                    self?.statusMessage = status
+                }
             }
 
             statusMessage = "Connecting to \(beacon.displayName)…"
@@ -630,9 +634,16 @@ struct ScanView: View {
                     Task { @MainActor [weak self] in
                         let reason = error?.localizedDescription ?? "beacon timed out"
                         provisionLog?.log("disconnect", "Unexpected disconnect: \(reason)", isError: true)
-                        // If we're still in connecting or connected state, show failure
-                        if let self = self,
-                           self.provisioningState == .connecting || self.provisioningState == .connected {
+                        guard let self = self else { return }
+                        // DXSmart: disconnect during .connected is expected — beacon keeps
+                        // flashing after BLE drops. We'll reconnect when user taps Write Config.
+                        if self.provisioningState == .connected && beacon.type == .dxsmart {
+                            provisionLog?.log("disconnect", "DXSmart idle disconnect — beacon still flashing, ignoring")
+                            return
+                        }
+                        // For all other active states, treat disconnect as failure
+                        if self.provisioningState == .connecting || self.provisioningState == .connected ||
+                           self.provisioningState == .writing || self.provisioningState == .verifying {
                             self.provisioningState = .failed
                             self.errorMessage = "Beacon disconnected: \(reason)"
                         }
@@ -713,6 +724,15 @@ struct ScanView: View {
         statusMessage = "Writing config to DX-Smart…"
 
         do {
+            // Reconnect if the beacon dropped BLE during the "confirm flashing" wait
+            if !provisioner.isConnected {
+                provisionLog.log("write", "Beacon disconnected while waiting — reconnecting…")
+                statusMessage = "Reconnecting to beacon…"
+                try await provisioner.connect()
+                provisionLog.log("write", "Reconnected — writing config…")
+                statusMessage = "Writing config to DX-Smart…"
+            }
+
             try await provisioner.writeConfig(config)
             provisioner.disconnect()