feat: Add WalletService with createWallet Impl

bdk_demo/lib/providers/wallet_providers.dart

@@ -1,8 +1,15 @@
+import 'package:bdk_demo/models/wallet_record.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
-
-import '../models/wallet_record.dart';
+import 'package:bdk_dart/bdk.dart';
 import 'settings_providers.dart';
 
+typedef WalletDisposer = void Function(Wallet wallet);
+
+final walletDisposerProvider = Provider<WalletDisposer>(
+  (ref) =>
+      (wallet) => wallet.dispose(),
+);
+
 final activeWalletRecordProvider =
     NotifierProvider<ActiveWalletRecordNotifier, WalletRecord?>(
       ActiveWalletRecordNotifier.new,
@@ -16,6 +23,43 @@ class ActiveWalletRecordNotifier extends Notifier<WalletRecord?> {
   void clear() => state = null;
 }
 
+final activeWalletProvider = NotifierProvider<ActiveWalletNotifier, Wallet?>(
+  ActiveWalletNotifier.new,
+);
+
+class ActiveWalletNotifier extends Notifier<Wallet?> {
+  late WalletDisposer _walletDisposer;
+  Wallet? _currentWallet;
+
+  void _disposeWallet(Wallet? wallet) {
+    if (wallet == null) return;
+    _walletDisposer(wallet);
+  }
+
+  @override
+  Wallet? build() {
+    _walletDisposer = ref.read(walletDisposerProvider);
+    _currentWallet = null;
+    ref.onDispose(() => _disposeWallet(_currentWallet));
+    return null;
+  }
+
+  void set(Wallet wallet) {
+    if (identical(_currentWallet, wallet)) {
+      return;
+    }
+    _disposeWallet(_currentWallet);
+    _currentWallet = wallet;
+    state = wallet;
+  }
+
+  void clear() {
+    _disposeWallet(_currentWallet);
+    _currentWallet = null;
+    state = null;
+  }
+}
+
 final walletRecordsProvider =
     NotifierProvider<WalletRecordsNotifier, List<WalletRecord>>(
       WalletRecordsNotifier.new,
@@ -48,5 +92,4 @@ class WalletRecordsNotifier extends Notifier<List<WalletRecord>> {
   }
 }
 
-// TODO: Add activeWalletProvider.
 // TODO: Add balanceProvider, syncStateProvider.

bdk_demo/lib/services/storage_service.dart

@@ -1,9 +1,8 @@
 import 'dart:convert';
+import 'package:bdk_demo/models/wallet_record.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
-import '../models/wallet_record.dart';
-
 abstract final class _PrefKeys {
   static const introDone = 'intro_done';
   static const darkTheme = 'dark_theme';

bdk_demo/lib/services/wallet_network_mapper.dart

@@ -0,0 +1,10 @@
+import 'package:bdk_dart/bdk.dart';
+import 'package:bdk_demo/models/wallet_record.dart';
+
+extension WalletNetworkX on WalletNetwork {
+  Network toBdkNetwork() => switch (this) {
+    WalletNetwork.signet => Network.signet,
+    WalletNetwork.testnet => Network.testnet,
+    WalletNetwork.regtest => Network.regtest,
+  };
+}

bdk_demo/test/README.md

@@ -0,0 +1,12 @@
+# Test Layout
+
+Tests are grouped by app layer to keep the suite easy to navigate as features grow.
+
+- `test/presentation/`: widget and UI behavior tests
+- `test/providers/`: Riverpod notifier/provider state tests
+- `test/services/`: service and mapping/unit logic tests
+- `test/integration/` (future): multi-service or app-flow integration tests
+
+Naming convention:
+- Use `*_test.dart` suffix.
+- Prefer behavior-focused names (example: `app_shell_test.dart`).

bdk_demo/test/providers/active_wallet_notifier_test.dart

@@ -0,0 +1,91 @@
+import 'package:bdk_dart/bdk.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:bdk_demo/providers/wallet_providers.dart';
+
+const _testExtendedPrivKey =
+    'tprv8ZgxMBicQKsPf2qfrEygW6fdYseJDDrVnDv26PH5BHdvSuG6ecCbHqLVof9yZcMoM31z9ur3tTYbSnr1WBqbGX97CbXcmp5H6qeMpyvx35B';
+
+Wallet _createTestWallet() {
+  final descriptor = Descriptor(
+    descriptor: 'wpkh($_testExtendedPrivKey/84h/1h/0h/0/*)',
+    network: Network.testnet,
+  );
+  final changeDescriptor = Descriptor(
+    descriptor: 'wpkh($_testExtendedPrivKey/84h/1h/0h/1/*)',
+    network: Network.testnet,
+  );
+  return Wallet(
+    descriptor: descriptor,
+    changeDescriptor: changeDescriptor,
+    network: Network.testnet,
+    persister: Persister.newInMemory(),
+    lookahead: 25,
+  );
+}
+
+void main() {
+  group('ActiveWalletNotifier', () {
+    test('set() with same wallet twice keeps state and avoids disposal', () {
+      var disposeCalls = 0;
+      final container = ProviderContainer(
+        overrides: [
+          walletDisposerProvider.overrideWithValue((wallet) {
+            disposeCalls += 1;
+            wallet.dispose();
+          }),
+        ],
+      );
+      addTearDown(container.dispose);
+
+      final notifier = container.read(activeWalletProvider.notifier);
+      final wallet = _createTestWallet();
+
+      notifier.set(wallet);
+      notifier.set(wallet);
+
+      expect(disposeCalls, 0);
+      expect(identical(container.read(activeWalletProvider), wallet), isTrue);
+    });
+
+    test('disposes current wallet when provider is disposed', () {
+      var disposeCalls = 0;
+      final container = ProviderContainer(
+        overrides: [
+          walletDisposerProvider.overrideWithValue((wallet) {
+            disposeCalls += 1;
+            wallet.dispose();
+          }),
+        ],
+      );
+
+      final notifier = container.read(activeWalletProvider.notifier);
+      notifier.set(_createTestWallet());
+
+      container.dispose();
+
+      expect(disposeCalls, 1);
+    });
+
+    test('clear() disposes wallet and sets state to null', () {
+      var disposeCalls = 0;
+      final container = ProviderContainer(
+        overrides: [
+          walletDisposerProvider.overrideWithValue((wallet) {
+            disposeCalls += 1;
+            wallet.dispose();
+          }),
+        ],
+      );
+      addTearDown(container.dispose);
+
+      final notifier = container.read(activeWalletProvider.notifier);
+      notifier.set(_createTestWallet());
+
+      notifier.clear();
+
+      expect(disposeCalls, 1);
+      expect(container.read(activeWalletProvider), isNull);
+    });
+  });
+}

bdk_demo/test/services/wallet_network_mapper_test.dart

@@ -0,0 +1,20 @@
+import 'package:bdk_dart/bdk.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:bdk_demo/models/wallet_record.dart';
+import 'package:bdk_demo/services/wallet_network_mapper.dart';
+
+void main() {
+  group('WalletNetworkX.toBdkNetwork', () {
+    test('maps signet correctly', () {
+      expect(WalletNetwork.signet.toBdkNetwork(), Network.signet);
+    });
+
+    test('maps testnet correctly', () {
+      expect(WalletNetwork.testnet.toBdkNetwork(), Network.testnet);
+    });
+
+    test('maps regtest correctly', () {
+      expect(WalletNetwork.regtest.toBdkNetwork(), Network.regtest);
+    });
+  });
+}