Merge pull request 'fix: reconnect retry for unexpected BLE disconnects' (#8) from schwifty/reconnect-on-unexpected-disconnect into main

Instead of immediately failing on disconnect during authenticating or
writing states, retry up to 2 times with backoff. Resets passwordIndex
on reconnect so re-auth starts fresh (fixes issue where burned password
attempts caused retry failures). Also fixes passwordIndex reset in the
device-info safety-net reconnect path.

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

PayfritBeacon/BeaconProvisioner.swift

@@ -179,8 +179,10 @@ class BeaconProvisioner: NSObject, ObservableObject {
     // Connection retry state
     private var connectionRetryCount = 0
     private var deviceInfoRetryCount = 0
+    private var disconnectRetryCount = 0
     private static let MAX_CONNECTION_RETRIES = 3
     private static let MAX_DEVICE_INFO_RETRIES = 2
+    private static let MAX_DISCONNECT_RETRIES = 2
     private var currentBeacon: DiscoveredBeacon?
 
     override init() {
@@ -222,6 +224,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
         self.isTerminating = false
         self.connectionRetryCount = 0
         self.deviceInfoRetryCount = 0
+        self.disconnectRetryCount = 0
         self.currentBeacon = beacon
 
         state = .connecting
@@ -270,6 +273,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
         self.allDiscoveredServices.removeAll()
         self.connectionRetryCount = 0
         self.deviceInfoRetryCount = 0
+        self.disconnectRetryCount = 0
         self.isTerminating = false
         self.currentBeacon = beacon
         self.servicesToExplore.removeAll()
@@ -308,6 +312,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
         isTerminating = false
         connectionRetryCount = 0
         deviceInfoRetryCount = 0
+        disconnectRetryCount = 0
         currentBeacon = nil
         state = .idle
         progress = ""
@@ -888,6 +893,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
         characteristics.removeAll()
         connectionRetryCount = 0
         deviceInfoRetryCount = 0
+        disconnectRetryCount = 0
         currentBeacon = nil
         operationMode = .provisioning
         state = .idle
@@ -1019,6 +1025,7 @@ extension BeaconProvisioner: CBCentralManagerDelegate {
             dxSmartNotifySubscribed = false
             dxSmartCommandQueue.removeAll()
             dxSmartWriteIndex = 0
+            passwordIndex = 0
             characteristics.removeAll()
             responseBuffer.removeAll()
             state = .connecting
@@ -1034,8 +1041,36 @@ extension BeaconProvisioner: CBCentralManagerDelegate {
             return
         }
 
-        // All other disconnects are unexpected
+        // Unexpected disconnect during auth or writing — retry with full reconnect
-        DebugLog.shared.log("BLE: UNEXPECTED disconnect — state=\(state) writeIdx=\(dxSmartWriteIndex) queueCount=\(dxSmartCommandQueue.count) authenticated=\(dxSmartAuthenticated)")
+        if (state == .authenticating || state == .writing) && disconnectRetryCount < BeaconProvisioner.MAX_DISCONNECT_RETRIES {
+            disconnectRetryCount += 1
+            DebugLog.shared.log("BLE: Disconnect during \(state) — reconnecting (attempt \(disconnectRetryCount)/\(BeaconProvisioner.MAX_DISCONNECT_RETRIES))")
+            progress = "Beacon disconnected, reconnecting (\(disconnectRetryCount)/\(BeaconProvisioner.MAX_DISCONNECT_RETRIES))..."
+
+            // Reset connection state for clean reconnect
+            dxSmartAuthenticated = false
+            dxSmartNotifySubscribed = false
+            dxSmartCommandQueue.removeAll()
+            dxSmartWriteIndex = 0
+            passwordIndex = 0
+            characteristics.removeAll()
+            responseBuffer.removeAll()
+            state = .connecting
+
+            let delay = Double(disconnectRetryCount) + 1.0  // 2s, 3s backoff
+            DispatchQueue.main.asyncAfter(deadline: .now() + delay) { [weak self] in
+                guard let self = self, let beacon = self.currentBeacon else { return }
+                guard self.state == .connecting else { return }
+                let resolvedPeripheral = self.resolvePeripheral(beacon)
+                self.peripheral = resolvedPeripheral
+                resolvedPeripheral.delegate = self
+                self.centralManager.connect(resolvedPeripheral, options: nil)
+            }
+            return
+        }
+
+        // All retries exhausted or disconnect in unexpected state — fail
+        DebugLog.shared.log("BLE: UNEXPECTED disconnect — state=\(state) writeIdx=\(dxSmartWriteIndex) queueCount=\(dxSmartCommandQueue.count) authenticated=\(dxSmartAuthenticated) disconnectRetries=\(disconnectRetryCount)")
         fail("Unexpected disconnect (state: \(state))", code: .disconnected)
     }
 }