fix(nfc): stop leaking sessions that wedge polling with a 408

lib/core/core_locator.dart

@@ -7,6 +7,7 @@ import 'package:bb_mobile/core/fees/fees_locator.dart';
 import 'package:bb_mobile/features/labels/labels_facade.dart';
 import 'package:bb_mobile/core/ledger/ledger_locator.dart';
 import 'package:bb_mobile/core/mempool/mempool_locator.dart';
+import 'package:bb_mobile/core/nfc/nfc_locator.dart';
 import 'package:bb_mobile/core/payjoin/payjoin_locator.dart';
 import 'package:bb_mobile/core/recoverbull/recoverbull_locator.dart';
 import 'package:bb_mobile/core/seed/seed_locator.dart';
@@ -40,6 +41,7 @@ class CoreLocator {
     Bip85DerivationsLocator.registerDatasources(locator);
     LedgerLocator.registerDatasources(locator);
     BitBoxCoreLocator.registerDatasources(locator);
+    NfcLocator.registerDatasources(locator);
   }
 
   static void registerPorts(GetIt locator) {

lib/core/nfc/data/nfc_error_mapper.dart

@@ -0,0 +1,46 @@
+import 'dart:async';
+
+import 'package:bb_mobile/core/nfc/domain/nfc_failure.dart';
+import 'package:flutter/services.dart';
+
+const _userCancelledMarker = 'Session invalidated by user';
+
+const _tagLostMarkers = [
+  'Tag connection lost',
+  'Read NDEF error',
+  'Error connecting to card',
+  'Tag already removed',
+];
+
+NfcFailure nfcFailureFromError(Object error, {required bool isWrite}) {
+  final details = error.toString();
+
+  if (details.contains(_userCancelledMarker)) {
+    return NfcCancelledFailure(details);
+  }
+
+  if (error is TimeoutException) return NfcTimeoutFailure(details);
+
+  if (error is PlatformException) {
+    switch (error.code) {
+      case '400':
+        return NfcInvalidPayloadFailure(details);
+      case '404':
+        return NfcDisabledFailure(details);
+      case '405':
+        return NfcUnsupportedTagFailure(details);
+      case '406':
+        return NfcBusyFailure(details);
+      case '408':
+        return NfcTimeoutFailure(details);
+      case '409':
+        return NfcCancelledFailure(details);
+      case '503':
+        return NfcTagLostFailure(details);
+    }
+  }
+
+  if (_tagLostMarkers.any(details.contains)) return NfcTagLostFailure(details);
+
+  return isWrite ? NfcWriteFailure(details) : NfcUnexpectedFailure(details);
+}

lib/core/nfc/data/nfc_kit_datasource.dart

@@ -0,0 +1,66 @@
+import 'package:flutter_nfc_kit/flutter_nfc_kit.dart';
+import 'package:ndef/ndef.dart' as ndef;
+
+abstract interface class NfcKitDatasource {
+  Future<NFCAvailability> availability();
+
+  Future<NFCTag> poll({
+    required Duration timeout,
+    required String iosAlertMessage,
+  });
+
+  Future<List<ndef.NDEFRecord>> readNdefRecords();
+
+  Future<void> writeTextRecord(String data);
+
+  Future<void> finish({String? iosAlertMessage, String? iosErrorMessage});
+
+  Future<void> setIosAlertMessage(String message);
+
+  Future<void> iosRestartPolling();
+}
+
+final class FlutterNfcKitDatasource implements NfcKitDatasource {
+  const FlutterNfcKitDatasource();
+
+  @override
+  Future<NFCAvailability> availability() => FlutterNfcKit.nfcAvailability;
+
+  @override
+  Future<NFCTag> poll({
+    required Duration timeout,
+    required String iosAlertMessage,
+  }) => FlutterNfcKit.poll(
+    timeout: timeout,
+    iosAlertMessage: iosAlertMessage,
+    readIso15693: true,
+    readIso18092: false,
+  );
+
+  @override
+  Future<List<ndef.NDEFRecord>> readNdefRecords() =>
+      FlutterNfcKit.readNDEFRecords();
+
+  @override
+  Future<void> writeTextRecord(String data) => FlutterNfcKit.writeNDEFRecords([
+    ndef.TextRecord(
+      text: data,
+      language: 'en',
+      encoding: ndef.TextEncoding.UTF8,
+    ),
+  ]);
+
+  @override
+  Future<void> finish({String? iosAlertMessage, String? iosErrorMessage}) =>
+      FlutterNfcKit.finish(
+        iosAlertMessage: iosAlertMessage,
+        iosErrorMessage: iosErrorMessage,
+      );
+
+  @override
+  Future<void> setIosAlertMessage(String message) =>
+      FlutterNfcKit.setIosAlertMessage(message);
+
+  @override
+  Future<void> iosRestartPolling() => FlutterNfcKit.iosRestartPolling();
+}