Initial setup: Flutter blockchain explorer app

- Clean architecture with feature-based organization
- Riverpod state management, Dio HTTP, GoRouter navigation
- Dashboard, blocks, wallet, transactions, mining screens
- Dark crypto theme with JetBrains Mono font

.gitignore

@@ -0,0 +1,30 @@
+*.class
+*.lock
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.dart_tool/
+.flutter-plugins
+.flutter-plugins-dependencies
+.packages
+.pub-cache/
+.pub/
+build/
+flutter_*.png
+linked_*.ds
+unlinked.ds
+unlinked_spec.ds
+.idea/
+.vagrant/
+.sconsign.dblite
+.svn/
+*.iml
+*.ipr
+*.iws
+.env

README.md

@@ -0,0 +1,100 @@
+# blockchain-flutter
+
+Flutter app for blockchain explorer, wallet management, and mining. Connects to the blockchain node via REST API.
+
+## Architecture
+
+Clean Architecture with feature-based organization:
+
+```
+lib/
+├── main.dart
+├── core/
+│   ├── network/
+│   │   └── api_client.dart        # Dio HTTP client setup
+│   ├── theme/
+│   │   └── app_theme.dart         # Dark theme, crypto aesthetic
+│   └── utils/
+│       └── formatters.dart        # Amount, hash, date formatting
+├── features/
+│   ├── dashboard/                 # Home: chain stats, recent blocks
+│   │   ├── dashboard_screen.dart
+│   │   └── dashboard_provider.dart
+│   ├── blocks/                    # Block explorer (list + detail)
+│   │   ├── blocks_screen.dart
+│   │   ├── block_detail_screen.dart
+│   │   └── blocks_provider.dart
+│   ├── wallet/                    # Create, view balance, list wallets
+│   │   ├── wallet_screen.dart
+│   │   └── wallet_provider.dart
+│   ├── transactions/              # Send tx, pending list
+│   │   ├── transactions_screen.dart
+│   │   ├── send_tx_screen.dart
+│   │   └── transactions_provider.dart
+│   └── mining/                    # Mine button, difficulty info
+│       ├── mining_screen.dart
+│       └── mining_provider.dart
+└── routing/
+    └── app_router.dart            # GoRouter navigation
+```
+
+## Tech Stack
+
+| Component | Choice | Rationale |
+|-----------|--------|-----------|
+| State management | Riverpod | Less boilerplate than BLoC, familiar |
+| HTTP client | Dio | Interceptors, retry support |
+| Navigation | GoRouter | Declarative routing |
+| Models | Freezed + json_serializable | Immutable data classes |
+| Secure storage | flutter_secure_storage | Wallet private keys |
+| Charts | fl_chart | Chain visualization |
+| Real-time | Polling (5-10s) | Simple, no WebSocket needed |
+
+## Features
+
+- **Dashboard**: chain height, difficulty, block reward, recent blocks
+- **Block Explorer**: browse blocks, view transactions per block
+- **Wallet**: generate keypairs, check balances, manage multiple wallets
+- **Transactions**: send signed transactions, view pending pool
+- **Mining**: one-tap mining, difficulty display, reward info
+
+## Screens
+
+1. **Dashboard** - overview with chain stats and recent activity
+2. **Blocks** - paginated block list with expandable details
+3. **Block Detail** - full block info with transaction list
+4. **Wallets** - wallet list with balances, create new
+5. **Send Transaction** - form: from, to, amount, sign & submit
+6. **Pending Transactions** - current mempool
+7. **Mining** - mine button with result display
+
+## Quick Start
+
+```bash
+# Install dependencies
+flutter pub get
+
+# Generate code (Freezed models)
+dart run build_runner build --delete-conflicting-outputs
+
+# Run (blockchain-node must be running on localhost:3000)
+flutter run
+
+# Run on web
+flutter run -d chrome
+```
+
+## Configuration
+
+Node URL is configured in `lib/core/network/api_client.dart`. Defaults to `http://localhost:3000`.
+
+For Android emulator, use `http://10.0.2.2:3000` to reach host localhost.
+
+## Related Repos
+
+- [blockchain-core](../blockchain-core) - Core library + REST API node
+- [blockchain-cli](../blockchain-cli) - Rust CLI tool
+
+## License
+
+MIT

lib/core/network/api_client.dart

@@ -0,0 +1,105 @@
+import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
+
+class ApiClient {
+  static const String _defaultBaseUrl = 'http://localhost:3000';
+  // Use 10.0.2.2 for Android emulator to reach host localhost
+  static const String _androidEmulatorUrl = 'http://10.0.2.2:3000';
+
+  late final Dio dio;
+
+  ApiClient({String? baseUrl}) {
+    final url = baseUrl ?? _resolveBaseUrl();
+
+    dio = Dio(BaseOptions(
+      baseUrl: url,
+      connectTimeout: const Duration(seconds: 5),
+      receiveTimeout: const Duration(seconds: 10),
+      headers: {'Content-Type': 'application/json'},
+    ));
+
+    dio.interceptors.add(LogInterceptor(
+      requestBody: true,
+      responseBody: true,
+      logPrint: (log) => debugPrint(log.toString()),
+    ));
+  }
+
+  static String _resolveBaseUrl() {
+    // Android emulator uses 10.0.2.2 to reach host machine
+    if (defaultTargetPlatform == TargetPlatform.android) {
+      return _androidEmulatorUrl;
+    }
+    return _defaultBaseUrl;
+  }
+
+  // Chain
+  Future<Map<String, dynamic>> getChainInfo() async {
+    final response = await dio.get('/api/chain/info');
+    return response.data;
+  }
+
+  Future<Map<String, dynamic>> validateChain() async {
+    final response = await dio.post('/api/chain/validate');
+    return response.data;
+  }
+
+  // Blocks
+  Future<Map<String, dynamic>> getBlocks({int offset = 0, int limit = 10}) async {
+    final response = await dio.get('/api/blocks', queryParameters: {
+      'offset': offset,
+      'limit': limit,
+    });
+    return response.data;
+  }
+
+  Future<Map<String, dynamic>> getBlock(String hash) async {
+    final response = await dio.get('/api/blocks/$hash');
+    return response.data;
+  }
+
+  // Wallets
+  Future<Map<String, dynamic>> createWallet() async {
+    final response = await dio.post('/api/wallets');
+    return response.data;
+  }
+
+  Future<Map<String, dynamic>> getBalance(String address) async {
+    final response = await dio.get('/api/wallets/$address/balance');
+    return response.data;
+  }
+
+  // Transactions
+  Future<Map<String, dynamic>> submitTransaction(Map<String, dynamic> tx) async {
+    final response = await dio.post('/api/transactions', data: tx);
+    return response.data;
+  }
+
+  Future<List<dynamic>> getPendingTransactions() async {
+    final response = await dio.get('/api/transactions/pending');
+    return response.data;
+  }
+
+  // Mining
+  Future<Map<String, dynamic>> mine(String minerAddress) async {
+    final response = await dio.post('/api/mine', data: {
+      'miner_address': minerAddress,
+    });
+    return response.data;
+  }
+
+  Future<Map<String, dynamic>> getMiningStatus() async {
+    final response = await dio.get('/api/mining/status');
+    return response.data;
+  }
+
+  // Health
+  Future<bool> healthCheck() async {
+    try {
+      await dio.get('/api/health');
+      return true;
+    } catch (_) {
+      return false;
+    }
+  }
+}

lib/core/theme/app_theme.dart

@@ -0,0 +1,49 @@
+import 'package:flutter/material.dart';
+import 'package:google_fonts/google_fonts.dart';
+
+class AppTheme {
+  static const _primaryColor = Color(0xFF6C63FF);
+  static const _accentColor = Color(0xFF00D9FF);
+  static const _backgroundColor = Color(0xFF0D1117);
+  static const _surfaceColor = Color(0xFF161B22);
+  static const _cardColor = Color(0xFF21262D);
+
+  static ThemeData get darkTheme {
+    return ThemeData(
+      useMaterial3: true,
+      brightness: Brightness.dark,
+      colorScheme: const ColorScheme.dark(
+        primary: _primaryColor,
+        secondary: _accentColor,
+        surface: _surfaceColor,
+      ),
+      scaffoldBackgroundColor: _backgroundColor,
+      cardColor: _cardColor,
+      textTheme: GoogleFonts.jetBrainsMonoTextTheme(
+        ThemeData.dark().textTheme,
+      ),
+      appBarTheme: const AppBarTheme(
+        backgroundColor: _surfaceColor,
+        elevation: 0,
+      ),
+      elevatedButtonTheme: ElevatedButtonThemeData(
+        style: ElevatedButton.styleFrom(
+          backgroundColor: _primaryColor,
+          foregroundColor: Colors.white,
+          padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
+          shape: RoundedRectangleBorder(
+            borderRadius: BorderRadius.circular(8),
+          ),
+        ),
+      ),
+      cardTheme: CardTheme(
+        color: _cardColor,
+        elevation: 0,
+        shape: RoundedRectangleBorder(
+          borderRadius: BorderRadius.circular(12),
+          side: BorderSide(color: Colors.white.withAlpha(25)),
+        ),
+      ),
+    );
+  }
+}

lib/core/utils/formatters.dart

@@ -0,0 +1,31 @@
+import 'package:intl/intl.dart';
+
+class Formatters {
+  /// Format a hash for display (first 8 + ... + last 8).
+  static String truncateHash(String hash, {int chars = 8}) {
+    if (hash.length <= chars * 2) return hash;
+    return '${hash.substring(0, chars)}...${hash.substring(hash.length - chars)}';
+  }
+
+  /// Format amount from smallest unit to display unit.
+  /// 50_000_000 -> "50.000000"
+  static String formatAmount(int amount, {int decimals = 6}) {
+    final value = amount / 1000000;
+    return value.toStringAsFixed(decimals);
+  }
+
+  /// Format a timestamp string to readable date.
+  static String formatTimestamp(String timestamp) {
+    try {
+      final dt = DateTime.parse(timestamp);
+      return DateFormat('yyyy-MM-dd HH:mm:ss').format(dt.toLocal());
+    } catch (_) {
+      return timestamp;
+    }
+  }
+
+  /// Format large numbers with comma separators.
+  static String formatNumber(int number) {
+    return NumberFormat('#,###').format(number);
+  }
+}

lib/features/blocks/block_detail_screen.dart

@@ -0,0 +1,21 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class BlockDetailScreen extends ConsumerWidget {
+  final String hash;
+
+  const BlockDetailScreen({super.key, required this.hash});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Block Detail')),
+      body: Center(
+        child: Text(
+          'Block Detail\n\nHash: $hash',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/features/blocks/blocks_screen.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class BlocksScreen extends ConsumerWidget {
+  const BlocksScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Block Explorer')),
+      body: const Center(
+        child: Text(
+          'Block Explorer\n\nBrowse blocks with pagination.',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/features/dashboard/dashboard_screen.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class DashboardScreen extends ConsumerWidget {
+  const DashboardScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Dashboard')),
+      body: const Center(
+        child: Text(
+          'Blockchain Dashboard\n\nChain stats, recent blocks, and network overview.',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/features/mining/mining_screen.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class MiningScreen extends ConsumerWidget {
+  const MiningScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Mining')),
+      body: const Center(
+        child: Text(
+          'Mining\n\nMine blocks, view difficulty and rewards.',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/features/transactions/send_tx_screen.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class SendTxScreen extends ConsumerWidget {
+  const SendTxScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Send Transaction')),
+      body: const Center(
+        child: Text(
+          'Send Transaction\n\nForm: from, to, amount.',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/features/transactions/transactions_screen.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class TransactionsScreen extends ConsumerWidget {
+  const TransactionsScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Transactions')),
+      body: const Center(
+        child: Text(
+          'Pending Transactions\n\nView mempool.',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/features/wallet/wallet_screen.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+class WalletScreen extends ConsumerWidget {
+  const WalletScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Wallets')),
+      body: const Center(
+        child: Text(
+          'Wallet Management\n\nCreate wallets, view balances.',
+          textAlign: TextAlign.center,
+        ),
+      ),
+    );
+  }
+}

lib/main.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import 'core/theme/app_theme.dart';
+import 'routing/app_router.dart';
+
+void main() {
+  runApp(const ProviderScope(child: BlockchainApp()));
+}
+
+class BlockchainApp extends ConsumerWidget {
+  const BlockchainApp({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final router = ref.watch(appRouterProvider);
+
+    return MaterialApp.router(
+      title: 'Blockchain Explorer',
+      theme: AppTheme.darkTheme,
+      routerConfig: router,
+      debugShowCheckedModeBanner: false,
+    );
+  }
+}

lib/routing/app_router.dart

@@ -0,0 +1,95 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:go_router/go_router.dart';
+
+import '../features/dashboard/dashboard_screen.dart';
+import '../features/blocks/blocks_screen.dart';
+import '../features/blocks/block_detail_screen.dart';
+import '../features/wallet/wallet_screen.dart';
+import '../features/transactions/transactions_screen.dart';
+import '../features/transactions/send_tx_screen.dart';
+import '../features/mining/mining_screen.dart';
+
+final appRouterProvider = Provider<GoRouter>((ref) {
+  return GoRouter(
+    initialLocation: '/',
+    routes: [
+      ShellRoute(
+        builder: (context, state, child) => ScaffoldWithNav(child: child),
+        routes: [
+          GoRoute(
+            path: '/',
+            builder: (context, state) => const DashboardScreen(),
+          ),
+          GoRoute(
+            path: '/blocks',
+            builder: (context, state) => const BlocksScreen(),
+          ),
+          GoRoute(
+            path: '/blocks/:hash',
+            builder: (context, state) => BlockDetailScreen(
+              hash: state.pathParameters['hash']!,
+            ),
+          ),
+          GoRoute(
+            path: '/wallets',
+            builder: (context, state) => const WalletScreen(),
+          ),
+          GoRoute(
+            path: '/transactions',
+            builder: (context, state) => const TransactionsScreen(),
+          ),
+          GoRoute(
+            path: '/transactions/send',
+            builder: (context, state) => const SendTxScreen(),
+          ),
+          GoRoute(
+            path: '/mining',
+            builder: (context, state) => const MiningScreen(),
+          ),
+        ],
+      ),
+    ],
+  );
+});
+
+class ScaffoldWithNav extends StatelessWidget {
+  final Widget child;
+  const ScaffoldWithNav({super.key, required this.child});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: child,
+      bottomNavigationBar: NavigationBar(
+        selectedIndex: _calculateIndex(GoRouterState.of(context).uri.path),
+        onDestinationSelected: (index) => _onTap(context, index),
+        destinations: const [
+          NavigationDestination(icon: Icon(Icons.dashboard), label: 'Dashboard'),
+          NavigationDestination(icon: Icon(Icons.view_in_ar), label: 'Blocks'),
+          NavigationDestination(icon: Icon(Icons.account_balance_wallet), label: 'Wallets'),
+          NavigationDestination(icon: Icon(Icons.swap_horiz), label: 'Transactions'),
+          NavigationDestination(icon: Icon(Icons.hardware), label: 'Mining'),
+        ],
+      ),
+    );
+  }
+
+  int _calculateIndex(String path) {
+    if (path.startsWith('/blocks')) return 1;
+    if (path.startsWith('/wallets')) return 2;
+    if (path.startsWith('/transactions')) return 3;
+    if (path.startsWith('/mining')) return 4;
+    return 0;
+  }
+
+  void _onTap(BuildContext context, int index) {
+    switch (index) {
+      case 0: context.go('/');
+      case 1: context.go('/blocks');
+      case 2: context.go('/wallets');
+      case 3: context.go('/transactions');
+      case 4: context.go('/mining');
+    }
+  }
+}

pubspec.yaml

@@ -0,0 +1,34 @@
+name: blockchain_flutter
+description: Flutter app for blockchain explorer, wallet management, and mining.
+publish_to: 'none'
+version: 0.1.0
+
+environment:
+  sdk: ^3.6.0
+  flutter: ">=3.27.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  flutter_riverpod: ^2.6.1
+  riverpod_annotation: ^2.6.1
+  dio: ^5.7.0
+  go_router: ^14.8.1
+  freezed_annotation: ^2.4.4
+  json_annotation: ^4.9.0
+  flutter_secure_storage: ^9.2.4
+  fl_chart: ^0.70.2
+  intl: ^0.19.0
+  google_fonts: ^6.2.1
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  flutter_lints: ^5.0.0
+  build_runner: ^2.4.14
+  freezed: ^2.5.7
+  json_serializable: ^6.9.4
+  riverpod_generator: ^2.6.3
+
+flutter:
+  uses-material-design: true