# Clean Architecture Export Files Documentation

This document describes all barrel export files created for the retail POS application, following clean architecture principles.

## Overview

Barrel export files provide a clean, organized way to import code by:
- Simplifying imports across the codebase
- Enforcing layer separation and boundaries
- Making refactoring easier
- Improving IDE autocomplete
- Documenting module structure

## File Structure

```
lib/
├── core/
│   ├── core.dart                      # Main core export
│   ├── config/
│   │   └── config.dart                # Configuration exports
│   ├── constants/
│   │   └── constants.dart             # All constants
│   ├── database/
│   │   └── database.dart              # Database utilities
│   ├── di/
│   │   └── di.dart                    # Dependency injection
│   ├── errors/
│   │   └── errors.dart                # Exceptions & failures
│   ├── network/
│   │   └── network.dart               # HTTP & network
│   ├── storage/
│   │   └── storage.dart               # Secure storage
│   ├── theme/
│   │   └── theme.dart                 # Material 3 theme
│   ├── utils/
│   │   └── utils.dart                 # Utilities & helpers
│   └── widgets/
│       └── widgets.dart               # Core widgets (already exists)
├── features/
│   ├── features.dart                  # Main features export
│   ├── auth/
│   │   ├── auth.dart                  # Main auth export
│   │   ├── data/
│   │   │   ├── data.dart              # Auth data layer
│   │   │   ├── datasources/
│   │   │   └── models/
│   │   │       └── models.dart        # Auth models
│   │   ├── domain/
│   │   │   ├── domain.dart            # Auth domain layer
│   │   │   └── entities/
│   │   │       └── entities.dart      # Auth entities
│   │   └── presentation/
│   │       ├── presentation.dart      # Auth presentation layer
│   │       ├── pages/
│   │       │   └── pages.dart         # Auth pages
│   │       └── widgets/
│   │           └── widgets.dart       # Auth widgets
│   ├── categories/
│   │   ├── categories.dart            # Main categories export
│   │   ├── data/
│   │   │   ├── data.dart              # Categories data layer
│   │   │   ├── datasources/
│   │   │   │   └── datasources.dart   # Category data sources
│   │   │   └── models/
│   │   │       └── models.dart        # Category models
│   │   ├── domain/
│   │   │   ├── domain.dart            # Categories domain layer
│   │   │   ├── entities/
│   │   │   │   └── entities.dart      # Category entities
│   │   │   └── usecases/
│   │   │       └── usecases.dart      # Category use cases
│   │   └── presentation/
│   │       ├── presentation.dart      # Categories presentation layer
│   │       ├── pages/
│   │       │   └── pages.dart         # Category pages
│   │       ├── providers/
│   │       │   └── providers.dart     # Category providers (already exists)
│   │       └── widgets/
│   │           └── widgets.dart       # Category widgets (already exists)
│   ├── home/
│   │   ├── home.dart                  # Main home/cart export
│   │   ├── data/
│   │   │   ├── data.dart              # Cart data layer
│   │   │   ├── datasources/
│   │   │   │   └── datasources.dart   # Cart data sources
│   │   │   └── models/
│   │   │       └── models.dart        # Cart models
│   │   ├── domain/
│   │   │   ├── domain.dart            # Cart domain layer
│   │   │   ├── entities/
│   │   │   │   └── entities.dart      # Cart entities
│   │   │   └── usecases/
│   │   │       └── usecases.dart      # Cart use cases
│   │   └── presentation/
│   │       ├── presentation.dart      # Cart presentation layer
│   │       ├── pages/
│   │       │   └── pages.dart         # Cart pages
│   │       ├── providers/
│   │       │   └── providers.dart     # Cart providers (already exists)
│   │       └── widgets/
│   │           └── widgets.dart       # Cart widgets (already exists)
│   ├── products/
│   │   ├── products.dart              # Main products export
│   │   ├── data/
│   │   │   ├── data.dart              # Products data layer
│   │   │   ├── datasources/
│   │   │   │   └── datasources.dart   # Product data sources
│   │   │   └── models/
│   │   │       └── models.dart        # Product models
│   │   ├── domain/
│   │   │   ├── domain.dart            # Products domain layer
│   │   │   ├── entities/
│   │   │   │   └── entities.dart      # Product entities
│   │   │   └── usecases/
│   │   │       └── usecases.dart      # Product use cases
│   │   └── presentation/
│   │       ├── presentation.dart      # Products presentation layer
│   │       ├── pages/
│   │       │   └── pages.dart         # Product pages
│   │       ├── providers/
│   │       │   └── providers.dart     # Product providers
│   │       └── widgets/
│   │           └── widgets.dart       # Product widgets (already exists)
│   └── settings/
│       ├── settings.dart              # Main settings export
│       ├── data/
│       │   ├── data.dart              # Settings data layer
│       │   ├── datasources/
│       │   │   └── datasources.dart   # Settings data sources
│       │   └── models/
│       │       └── models.dart        # Settings models
│       ├── domain/
│       │   ├── domain.dart            # Settings domain layer
│       │   ├── entities/
│       │   │   └── entities.dart      # Settings entities
│       │   └── usecases/
│       │       └── usecases.dart      # Settings use cases
│       └── presentation/
│           ├── presentation.dart      # Settings presentation layer
│           ├── pages/
│           │   └── pages.dart         # Settings pages
│           ├── providers/
│           │   └── providers.dart     # Settings providers (already exists)
│           └── widgets/
│               └── widgets.dart       # Settings widgets
└── shared/
    └── shared.dart                    # Shared components export
```

## Usage Examples

### 1. Importing Entire Features

```dart
// Import complete auth feature (all layers)
import 'package:retail/features/auth/auth.dart';

// Import complete products feature
import 'package:retail/features/products/products.dart';

// Import all features at once
import 'package:retail/features/features.dart';
```

### 2. Importing Specific Layers

```dart
// Import only auth domain layer (entities + repositories)
import 'package:retail/features/auth/domain/domain.dart';

// Import only products presentation layer (pages + widgets + providers)
import 'package:retail/features/products/presentation/presentation.dart';

// Import only cart data layer
import 'package:retail/features/home/data/data.dart';
```

### 3. Importing Specific Components

```dart
// Import only auth entities
import 'package:retail/features/auth/domain/entities/entities.dart';

// Import only product models
import 'package:retail/features/products/data/models/models.dart';

// Import only category use cases
import 'package:retail/features/categories/domain/usecases/usecases.dart';

// Import only product providers
import 'package:retail/features/products/presentation/providers/providers.dart';
```

### 4. Importing Core Utilities

```dart
// Import all core utilities
import 'package:retail/core/core.dart';

// Import only constants
import 'package:retail/core/constants/constants.dart';

// Import only theme
import 'package:retail/core/theme/theme.dart';

// Import only network utilities
import 'package:retail/core/network/network.dart';

// Import only error handling
import 'package:retail/core/errors/errors.dart';
```

### 5. Importing Shared Components

```dart
// Import shared widgets
import 'package:retail/shared/shared.dart';
```

## Clean Architecture Benefits

### Layer Isolation

The export structure enforces clean architecture principles:

```dart
// ✅ GOOD: Domain layer importing from domain
import 'package:retail/features/products/domain/domain.dart';

// ❌ BAD: Domain layer importing from data/presentation
// Domain should never depend on outer layers
import 'package:retail/features/products/data/data.dart';
```

### Dependency Flow

Dependencies flow inward:
- **Presentation** → Domain ← Data
- **Data** → Domain (implements interfaces)
- **Domain** → Independent (pure business logic)

```dart
// In presentation layer - ✅ GOOD
import 'package:retail/features/products/domain/domain.dart';

// In data layer - ✅ GOOD
import 'package:retail/features/products/domain/domain.dart';

// In domain layer - ❌ NEVER
// import 'package:retail/features/products/data/data.dart';
// import 'package:retail/features/products/presentation/presentation.dart';
```

## Feature Export Hierarchy

Each feature follows this export hierarchy:

```
feature.dart                    # Top-level feature export
├── data/data.dart              # Data layer export
│   ├── datasources/datasources.dart
│   ├── models/models.dart
│   └── repositories/           # Implementations (exported directly)
├── domain/domain.dart          # Domain layer export
│   ├── entities/entities.dart
│   ├── repositories/           # Interfaces (exported directly)
│   └── usecases/usecases.dart
└── presentation/presentation.dart  # Presentation layer export
    ├── pages/pages.dart
    ├── providers/providers.dart
    └── widgets/widgets.dart
```

## Import Guidelines

### DO's

1. **Import at the appropriate level**
   ```dart
   // If you need the entire feature
   import 'package:retail/features/auth/auth.dart';

   // If you only need domain entities
   import 'package:retail/features/auth/domain/entities/entities.dart';
   ```

2. **Use barrel exports for cleaner code**
   ```dart
   // ✅ Clean and maintainable
   import 'package:retail/features/products/presentation/presentation.dart';

   // ❌ Messy and fragile
   import 'package:retail/features/products/presentation/pages/products_page.dart';
   import 'package:retail/features/products/presentation/widgets/product_card.dart';
   import 'package:retail/features/products/presentation/widgets/product_grid.dart';
   import 'package:retail/features/products/presentation/providers/products_provider.dart';
   ```

3. **Respect layer boundaries**
   ```dart
   // In a use case (domain layer)
   import 'package:retail/features/products/domain/domain.dart'; // ✅
   import 'package:retail/core/core.dart'; // ✅ (core is shared)
   ```

### DON'Ts

1. **Don't bypass barrel exports**
   ```dart
   // ❌ Bypasses barrel export
   import 'package:retail/features/products/data/models/product_model.dart';

   // ✅ Use barrel export
   import 'package:retail/features/products/data/models/models.dart';
   ```

2. **Don't violate layer dependencies**
   ```dart
   // In domain layer
   // ❌ Domain depends on outer layers
   import 'package:retail/features/products/data/data.dart';
   import 'package:retail/features/products/presentation/presentation.dart';
   ```

3. **Don't import entire feature when you need one layer**
   ```dart
   // ❌ Over-importing
   import 'package:retail/features/products/products.dart'; // Imports all layers
   // When you only need:
   import 'package:retail/features/products/domain/entities/entities.dart';
   ```

## Benefits Summary

### 1. Clean Imports
Before:
```dart
import 'package:retail/features/products/data/models/product_model.dart';
import 'package:retail/features/products/domain/entities/product.dart';
import 'package:retail/features/products/domain/repositories/product_repository.dart';
import 'package:retail/features/products/presentation/pages/products_page.dart';
import 'package:retail/features/products/presentation/widgets/product_card.dart';
import 'package:retail/features/products/presentation/widgets/product_grid.dart';
```

After:
```dart
import 'package:retail/features/products/products.dart';
```

### 2. Layer Isolation
- Domain layer never imports from data/presentation
- Each layer has clear boundaries
- Enforces dependency inversion

### 3. Easy Refactoring
- Change internal structure without breaking imports
- Move files within a layer without updating imports
- Rename files without affecting external code

### 4. Better IDE Support
- Autocomplete shows only exported items
- Easier to navigate code structure
- Clear module boundaries

### 5. Documentation
- Export files serve as documentation
- Shows what's public vs private
- Makes architecture explicit

## Migration Guide

If you have existing imports, migrate them gradually:

### Step 1: Update feature-level imports
```dart
// Old
import 'package:retail/features/products/presentation/pages/products_page.dart';

// New
import 'package:retail/features/products/presentation/pages/pages.dart';
```

### Step 2: Consolidate layer imports
```dart
// Old
import 'package:retail/features/products/presentation/pages/pages.dart';
import 'package:retail/features/products/presentation/widgets/widgets.dart';
import 'package:retail/features/products/presentation/providers/providers.dart';

// New
import 'package:retail/features/products/presentation/presentation.dart';
```

### Step 3: Use top-level feature import when appropriate
```dart
// If you need multiple layers
import 'package:retail/features/products/products.dart';
```

## Complete File List

Total export files created: **54 files**

### Core Module (10 files)
1. `/Users/ssg/project/retail/lib/core/core.dart`
2. `/Users/ssg/project/retail/lib/core/config/config.dart`
3. `/Users/ssg/project/retail/lib/core/constants/constants.dart`
4. `/Users/ssg/project/retail/lib/core/database/database.dart`
5. `/Users/ssg/project/retail/lib/core/di/di.dart`
6. `/Users/ssg/project/retail/lib/core/errors/errors.dart`
7. `/Users/ssg/project/retail/lib/core/network/network.dart`
8. `/Users/ssg/project/retail/lib/core/storage/storage.dart`
9. `/Users/ssg/project/retail/lib/core/theme/theme.dart`
10. `/Users/ssg/project/retail/lib/core/utils/utils.dart`

### Auth Feature (8 files)
11. `/Users/ssg/project/retail/lib/features/auth/auth.dart`
12. `/Users/ssg/project/retail/lib/features/auth/data/data.dart`
13. `/Users/ssg/project/retail/lib/features/auth/data/models/models.dart`
14. `/Users/ssg/project/retail/lib/features/auth/domain/domain.dart`
15. `/Users/ssg/project/retail/lib/features/auth/domain/entities/entities.dart`
16. `/Users/ssg/project/retail/lib/features/auth/presentation/presentation.dart`
17. `/Users/ssg/project/retail/lib/features/auth/presentation/pages/pages.dart`
18. `/Users/ssg/project/retail/lib/features/auth/presentation/widgets/widgets.dart` *(updated by flutter expert)*

### Products Feature (10 files)
19. `/Users/ssg/project/retail/lib/features/products/products.dart`
20. `/Users/ssg/project/retail/lib/features/products/data/data.dart`
21. `/Users/ssg/project/retail/lib/features/products/data/datasources/datasources.dart`
22. `/Users/ssg/project/retail/lib/features/products/data/models/models.dart`
23. `/Users/ssg/project/retail/lib/features/products/domain/domain.dart`
24. `/Users/ssg/project/retail/lib/features/products/domain/entities/entities.dart`
25. `/Users/ssg/project/retail/lib/features/products/domain/usecases/usecases.dart`
26. `/Users/ssg/project/retail/lib/features/products/presentation/presentation.dart`
27. `/Users/ssg/project/retail/lib/features/products/presentation/pages/pages.dart`
28. `/Users/ssg/project/retail/lib/features/products/presentation/providers/providers.dart`

### Categories Feature (10 files)
29. `/Users/ssg/project/retail/lib/features/categories/categories.dart`
30. `/Users/ssg/project/retail/lib/features/categories/data/data.dart`
31. `/Users/ssg/project/retail/lib/features/categories/data/datasources/datasources.dart`
32. `/Users/ssg/project/retail/lib/features/categories/data/models/models.dart`
33. `/Users/ssg/project/retail/lib/features/categories/domain/domain.dart`
34. `/Users/ssg/project/retail/lib/features/categories/domain/entities/entities.dart`
35. `/Users/ssg/project/retail/lib/features/categories/domain/usecases/usecases.dart`
36. `/Users/ssg/project/retail/lib/features/categories/presentation/presentation.dart`
37. `/Users/ssg/project/retail/lib/features/categories/presentation/pages/pages.dart`
38. `/Users/ssg/project/retail/lib/features/categories/presentation/providers/providers.dart` *(already exists)*

### Home/Cart Feature (10 files)
39. `/Users/ssg/project/retail/lib/features/home/home.dart`
40. `/Users/ssg/project/retail/lib/features/home/data/data.dart`
41. `/Users/ssg/project/retail/lib/features/home/data/datasources/datasources.dart`
42. `/Users/ssg/project/retail/lib/features/home/data/models/models.dart`
43. `/Users/ssg/project/retail/lib/features/home/domain/domain.dart`
44. `/Users/ssg/project/retail/lib/features/home/domain/entities/entities.dart`
45. `/Users/ssg/project/retail/lib/features/home/domain/usecases/usecases.dart`
46. `/Users/ssg/project/retail/lib/features/home/presentation/presentation.dart`
47. `/Users/ssg/project/retail/lib/features/home/presentation/pages/pages.dart`
48. `/Users/ssg/project/retail/lib/features/home/presentation/providers/providers.dart` *(already exists)*

### Settings Feature (10 files)
49. `/Users/ssg/project/retail/lib/features/settings/settings.dart`
50. `/Users/ssg/project/retail/lib/features/settings/data/data.dart`
51. `/Users/ssg/project/retail/lib/features/settings/data/datasources/datasources.dart`
52. `/Users/ssg/project/retail/lib/features/settings/data/models/models.dart`
53. `/Users/ssg/project/retail/lib/features/settings/domain/domain.dart`
54. `/Users/ssg/project/retail/lib/features/settings/domain/entities/entities.dart`
55. `/Users/ssg/project/retail/lib/features/settings/domain/usecases/usecases.dart`
56. `/Users/ssg/project/retail/lib/features/settings/presentation/presentation.dart`
57. `/Users/ssg/project/retail/lib/features/settings/presentation/pages/pages.dart`
58. `/Users/ssg/project/retail/lib/features/settings/presentation/providers/providers.dart` *(already exists)*
59. `/Users/ssg/project/retail/lib/features/settings/presentation/widgets/widgets.dart`

### Top-Level Exports (2 files)
60. `/Users/ssg/project/retail/lib/features/features.dart`
61. `/Users/ssg/project/retail/lib/shared/shared.dart`

### Documentation (1 file)
62. `/Users/ssg/project/retail/lib/EXPORTS_DOCUMENTATION.md`

---

## Maintenance

When adding new files to the project:

1. **New file in existing module**: Update the appropriate barrel export
2. **New module**: Create new barrel exports following the pattern
3. **Removing files**: Update barrel exports to remove deleted exports
4. **Renaming files**: Update barrel exports to reflect new names

## Support

For questions or issues with the export structure, refer to:
- This documentation
- Clean Architecture principles
- Feature-first organization patterns