lib/
├── app.dart                    # Main app widget
├── main.dart                   # App entry point
├── config/                     # Configuration
│   ├── constants.dart
│   ├── env.dart
│   ├── routes/
│   └── theme/
├── core/                       # Core utilities
│   ├── accessibility/
│   ├── animations/
│   ├── database/
│   ├── error/
│   ├── interactions/
│   ├── services/
│   ├── utils/
│   └── widgets/
├── features/                   # Feature modules
│   ├── entry/
│   ├── timeline/
│   ├── search/
│   ├── calendar/
│   ├── settings/
│   └── shared/
└── shared/                     # Shared widgets
    └── widgets/

feature_name/
├── data/
│   ├── models/               # Data models
│   └── services/             # API/database services
├── domain/
│   ├── entities/             # Business entities
│   └── repositories/         # Repository interfaces
└── presentation/
    ├── bloc/                 # State management
    ├── screens/              # Screen widgets
    └── widgets/              # Feature-specific widgets

// Good
const Text('Hello')
const SizedBox(height: 16)

// Bad
Text('Hello')
SizedBox(height: 16)

// Good
class UserProfile extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        const _ProfileHeader(),
        const _ProfileStats(),
        const _ProfileActions(),
      ],
    );
  }
}

class _ProfileHeader extends StatelessWidget {
  const _ProfileHeader();

  @override
  Widget build(BuildContext context) {
    // ...
  }
}

ListView.builder(
  itemBuilder: (context, index) {
    return ListItem(
      key: ValueKey(items[index].id),
      item: items[index],
    );
  },
)

class MyWidget extends StatefulWidget {
  @override
  State<MyWidget> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  late ScrollController _controller;

  @override
  void initState() {
    super.initState();
    _controller = ScrollController();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ListView(controller: _controller);
  }
}

try {
  final result = await apiCall();
  return result;
} catch (error, stackTrace) {
  ErrorHandler.logError(error, stackTrace: stackTrace);
  rethrow;
}

ErrorHandler.showErrorDialog(
  context,
  error,
  userMessage: 'Failed to load entries. Please try again.',
);

if (kDebugMode) {
  debugPrint('Error: $error');
}

test('should calculate total correctly', () {
  final calculator = Calculator();
  expect(calculator.add(2, 3), equals(5));
});

testWidgets('should display error message', (tester) async {
  await tester.pumpWidget(
    ErrorDisplay(message: 'Test error'),
  );

  expect(find.text('Test error'), findsOneWidget);
});

testWidgets('should create journal entry', (tester) async {
  // Navigate to create entry
  await tester.tap(find.byIcon(Icons.add));
  await tester.pumpAndSettle();

  // Fill form
  await tester.enterText(find.byKey(Key('title')), 'Test Entry');

  // Submit
  await tester.tap(find.text('Save'));
  await tester.pumpAndSettle();

  // Verify
  expect(find.text('Test Entry'), findsOneWidget);
});

/// Creates a journal entry with the given [title] and [content].
///
/// Throws [ValidationException] if title is empty.
/// Returns the created entry's ID.
Future<String> createEntry({
  required String title,
  required String content,
}) async {
  // Implementation
}

// Calculate weighted average based on emotion intensity
// Higher intensity emotions have more weight in the calculation
final weightedAverage = emotions
    .map((e) => e.value * e.intensity)
    .reduce((a, b) => a + b) / totalIntensity;

// TODO(username): Implement offline support
// TODO: Add unit tests for edge cases

class MassiveWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        // 500 lines of nested widgets
      ],
    );
  }
}

class OrganizedWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        const _Header(),
        const _Content(),
        const _Footer(),
      ],
    );
  }
}

setState(() {
  // Rebuilds entire parent and all children
});

// Use BLoC or local state in child widgets

Widget build(BuildContext context) {
  return Container(
    child: Text('Static text'), // Rebuilds on every parent rebuild
  );
}

Widget build(BuildContext context) {
  return Container(
    child: const Text('Static text'), // Never rebuilds
  );
}

class _State extends State<MyWidget> {
  late AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(...);
  }
  // Missing dispose - memory leak!
}

class _State extends State<MyWidget> {
  late AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(...);
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }
}

# Run analyzer
flutter analyze

# Fix auto-fixable issues
dart fix --apply

# Format code
dart format .

# Build in profile mode
flutter build ios --profile

# Run DevTools
flutter pub global activate devtools
flutter pub global run devtools

# Run tests with coverage
flutter test --coverage

# Generate HTML report
genhtml coverage/lcov.info -o coverage/html
open coverage/html/index.html