# System Architecture

## 3.1 Backend Architecture

### Laravel Framework Structure
```
app/
├── Console/           # Artisan commands
├── Http/              # HTTP layer
│   ├── Controllers/   # Request handlers
│   ├── Middleware/    # Request filters
│   └── Requests/      # Form validation
├── Models/            # Eloquent models
├── Services/          # Business logic
├── Observers/         # Model events
├── Notifications/     # Email notifications
├── Mail/              # Email templates
└── Providers/         # Service providers
```

### MVC Pattern Implementation
- **Models**: Data layer with Eloquent ORM
- **Views**: Frontend components (React)
- **Controllers**: Request handling and business logic
- **Services**: Complex business logic separation
- **Repositories**: Data access abstraction (future)

### Service Layer Architecture
```php
// Example service structure
class TournamentBracketService
{
    public function generateBracket(array $participants, string $type): Bracket
    public function advanceRound(Bracket $bracket, int $round): array
    public function applySeeding(array $participants): array
}
```

### API Design Principles
- **RESTful Endpoints**: Standard HTTP methods
- **Resource-Based URLs**: Clear resource identification
- **Consistent Responses**: Standardized JSON responses
- **Error Handling**: Comprehensive error responses
- **Authentication**: Token-based authentication

## 3.2 Frontend Architecture

### React Component Structure
```
resources/js/
├── components/        # Reusable components
├── pages/            # Page components
├── layouts/          # Layout components
├── hooks/            # Custom hooks
├── contexts/         # React contexts
├── lib/              # Utility functions
└── types/            # TypeScript types
```

### Component Architecture
- **Atomic Design**: Atoms, molecules, organisms
- **Composition**: Component composition over inheritance
- **Props Interface**: TypeScript interfaces for props
- **State Management**: React hooks and context
- **Event Handling**: Standard React patterns

### State Management
```typescript
// Context-based state management
interface AppContextType {
  user: User | null;
  tournaments: Tournament[];
  loading: boolean;
  error: string | null;
}
```

### Routing Strategy
- **Inertia.js**: Server-side routing with client-side navigation
- **Route Guards**: Authentication and authorization
- **Lazy Loading**: Component lazy loading
- **Nested Routes**: Hierarchical routing structure

## 3.3 Database Design

### Entity Relationship Diagram
```
Users (1) ──┐
            ├── (1) Teams (1) ──┐
            │                   ├── (M) Players
            │                   ├── (M) TeamOfficials
            │                   └── (M) Formations
            │
            ├── (M) Tournaments
            │
            └── (M) Payments

Tournaments (1) ──┐
                  ├── (M) Brackets
                  ├── (M) GameMatches
                  ├── (M) Teams (M) ──┐
                  │                  └── (M) Players
                  └── (M) Media
```

### Database Normalization
- **First Normal Form**: Atomic values
- **Second Normal Form**: No partial dependencies
- **Third Normal Form**: No transitive dependencies
- **BCNF**: Boyce-Codd Normal Form compliance

### Key Relationships
```php
// User relationships
User::hasMany(Team::class);
User::hasMany(Tournament::class);
User::hasMany(Payment::class);

// Tournament relationships
Tournament::hasMany(Bracket::class);
Tournament::hasMany(GameMatch::class);
Tournament::belongsToMany(Team::class);

// Team relationships
Team::belongsTo(User::class, 'captain_id');
Team::hasMany(Player::class);
Team::hasMany(TeamOfficial::class);
```

## 3.4 API Design

### RESTful Endpoints
```
GET    /api/tournaments           # List tournaments
POST   /api/tournaments           # Create tournament
GET    /api/tournaments/{id}      # Get tournament
PUT    /api/tournaments/{id}      # Update tournament
DELETE /api/tournaments/{id}      # Delete tournament

GET    /api/teams                 # List teams
POST   /api/teams                 # Create team
GET    /api/teams/{id}            # Get team
PUT    /api/teams/{id}            # Update team
DELETE /api/teams/{id}            # Delete team
```

### API Response Format
```json
{
  "success": true,
  "data": {
    "id": 1,
    "name": "Tournament Name",
    "status": "active"
  },
  "message": "Tournament retrieved successfully",
  "meta": {
    "pagination": {
      "current_page": 1,
      "total": 10
    }
  }
}
```

### Error Response Format
```json
{
  "success": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Validation failed",
    "details": {
      "name": ["The name field is required"]
    }
  }
}
```

## 3.5 Security Architecture

### Authentication System
- **Laravel Sanctum**: Token-based authentication
- **Session Management**: Secure session handling
- **Password Hashing**: bcrypt password hashing
- **Remember Tokens**: Persistent login tokens

### Authorization System
```php
// Role-based permissions
$user->hasRole('admin');
$user->hasPermission('tournaments.create');
$user->can('edit', $tournament);
```

### Security Measures
- **CSRF Protection**: Cross-site request forgery protection
- **XSS Prevention**: Input sanitization and output encoding
- **SQL Injection**: Parameterized queries with Eloquent
- **File Upload Security**: File type and size validation
- **Rate Limiting**: API rate limiting
- **HTTPS Enforcement**: SSL/TLS encryption

### Data Protection
- **Input Validation**: Comprehensive input validation
- **Output Encoding**: XSS prevention
- **File Security**: Secure file handling
- **Database Security**: Parameterized queries
- **API Security**: Token-based authentication

## 3.6 Deployment Architecture

### Production Environment
```
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   Load Balancer │    │   Web Server    │    │   Database      │
│   (Nginx)       │◄──►│   (Apache/Nginx)│◄──►│   (MySQL)       │
└─────────────────┘    └─────────────────┘    └─────────────────┘
         │                       │                       │
         │                       │                       │
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   CDN           │    │   File Storage  │    │   Backup        │
│   (CloudFlare)  │    │   (Local/Cloud) │    │   (Automated)   │
└─────────────────┘    └─────────────────┘    └─────────────────┘
```

### Development Environment
```
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   Development   │    │   Local Server  │    │   SQLite        │
│   Machine       │◄──►│   (Laravel)     │◄──►│   Database      │
└─────────────────┘    └─────────────────┘    └─────────────────┘
```

### Containerization (Future)
```dockerfile
# Dockerfile example
FROM php:8.2-fpm
RUN docker-php-ext-install pdo pdo_mysql
COPY . /var/www/html
WORKDIR /var/www/html
RUN composer install
```

### Monitoring and Logging
- **Application Logs**: Laravel logging system
- **Error Tracking**: Comprehensive error logging
- **Performance Monitoring**: Response time tracking
- **Security Monitoring**: Failed login attempts
- **Database Monitoring**: Query performance

---

## Architecture Benefits

### Scalability
- **Horizontal Scaling**: Load balancer support
- **Database Optimization**: Efficient queries and indexing
- **Caching Strategy**: Redis/Memcached support
- **CDN Integration**: Static asset optimization

### Maintainability
- **Clean Architecture**: Separation of concerns
- **SOLID Principles**: Object-oriented design
- **Code Standards**: PSR-12 compliance
- **Documentation**: Comprehensive documentation

### Performance
- **Optimized Queries**: Efficient database operations
- **Caching**: Multiple caching layers
- **Asset Optimization**: Minified and compressed assets
- **Database Indexing**: Strategic database indexes

### Security
- **Defense in Depth**: Multiple security layers
- **Input Validation**: Comprehensive input sanitization
- **Authentication**: Secure user authentication
- **Authorization**: Granular permission system

---

## Next Steps

- [Data Models](04_Data_Models.md) - Detailed data model documentation
- [API Documentation](05_API_Documentation.md) - Complete API reference
- [Security](11_Security.md) - Security implementation details
- [Deployment](14_Deployment.md) - Production deployment guide
