# Detailed Improvement Plan

## 1. Infrastructure & Deployment

### Service Isolation and Containerization
- **Microservices Architecture**
  ```
  /services
  ├── auth-service/
  │   ├── Dockerfile
  │   └── docker-compose.yml
  ├── event-service/
  │   ├── Dockerfile
  │   └── docker-compose.yml
  └── validation-service/
      ├── Dockerfile
      └── docker-compose.yml
  ```
- **Service Discovery**
  - Implement Consul for service registry
  - Add health check endpoints
  - Create service mesh with Istio

### API Gateway Implementation
```yaml
# api-gateway.yml
services:
  gateway:
    routes:
      - id: auth-service
        uri: lb://auth-service
        predicates:
          - Path=/api/auth/**
        filters:
          - RateLimit=100,1s
          - CircuitBreaker=3,10s
```

### Monitoring Stack
- **Distributed Tracing**
  ```python
  from opentelemetry import trace
  from opentelemetry.exporter import jaeger
  
  tracer = trace.get_tracer(__name__)
  with tracer.start_as_current_span("operation") as span:
      span.set_attribute("attribute", value)
  ```
- **Metrics Collection**
  - Prometheus for metrics
  - Grafana for visualization
  - Custom dashboards for each service

### Configuration Management
```python
# config_service.py
class ConfigService:
    def __init__(self):
        self.consul_client = Consul()
        
    def get_config(self, service_name: str) -> Dict:
        return self.consul_client.kv.get(f"config/{service_name}")
        
    def update_config(self, service_name: str, config: Dict):
        self.consul_client.kv.put(f"config/{service_name}", config)
```

## 2. Performance & Scaling

### Enhanced Caching Strategy
```python
# redis_cache.py
class RedisCache:
    def __init__(self):
        self.client = Redis(cluster_mode=True)
        
    async def get_or_set(self, key: str, callback: Callable):
        if value := await self.client.get(key):
            return value
        value = await callback()
        await self.client.set(key, value, ex=3600)
        return value
```

### Database Optimization
```sql
-- Sharding Example
CREATE TABLE users_shard_1 PARTITION OF users
    FOR VALUES WITH (modulus 3, remainder 0);
CREATE TABLE users_shard_2 PARTITION OF users
    FOR VALUES WITH (modulus 3, remainder 1);
```

### Event System Enhancement
```python
# event_publisher.py
class EventPublisher:
    def __init__(self):
        self.kafka_producer = KafkaProducer()
        
    async def publish(self, topic: str, event: Dict):
        await self.kafka_producer.send(
            topic,
            value=event,
            headers=[("version", "1.0")]
        )
```

### Background Processing
```python
# job_processor.py
class JobProcessor:
    def __init__(self):
        self.celery = Celery()
        self.connection_pool = ConnectionPool(max_size=100)
    
    @celery.task
    async def process_job(self, job_data: Dict):
        async with self.connection_pool.acquire() as conn:
            await conn.execute(job_data)
```

## 3. Security & Reliability

### API Security Enhancement
```python
# security.py
class SecurityMiddleware:
    def __init__(self):
        self.rate_limiter = RateLimiter()
        self.key_rotator = KeyRotator()
    
    async def process_request(self, request: Request):
        await self.rate_limiter.check(request.client_ip)
        await self.key_rotator.validate(request.api_key)
```

### Error Handling System
```python
# error_handler.py
class ErrorHandler:
    def __init__(self):
        self.sentry_client = Sentry()
        self.circuit_breaker = CircuitBreaker()
    
    async def handle_error(self, error: Exception):
        await self.sentry_client.capture_exception(error)
        await self.circuit_breaker.record_error()
```

### Testing Framework
```python
# integration_tests.py
class IntegrationTests:
    async def setup(self):
        self.containers = await TestContainers.start([
            "postgres", "redis", "kafka"
        ])
    
    async def test_end_to_end(self):
        await self.setup()
        # Test complete user journey
        await self.cleanup()
```

### Audit System
```python
# audit.py
class AuditLogger:
    def __init__(self):
        self.elastic = Elasticsearch()
    
    async def log_action(
        self,
        user_id: str,
        action: str,
        resource: str,
        changes: Dict
    ):
        await self.elastic.index({
            "user_id": user_id,
            "action": action,
            "resource": resource,
            "changes": changes,
            "timestamp": datetime.utcnow()
        })
```

## 4. Development Experience

### Domain-Driven Design
```
/src
├── domain/
│   ├── entities/
│   ├── value_objects/
│   └── aggregates/
├── application/
│   ├── commands/
│   └── queries/
└── infrastructure/
    ├── repositories/
    └── services/
```

### API Documentation
```python
# main.py
from fastapi import FastAPI
from fastapi.openapi.utils import get_openapi

app = FastAPI()

def custom_openapi():
    return get_openapi(
        title="WAG Management API",
        version="4.0.0",
        description="Complete API documentation",
        routes=app.routes
    )

app.openapi = custom_openapi
```

### Translation Management
```python
# i18n.py
class TranslationService:
    def __init__(self):
        self.translations = {}
        self.fallback_chain = ["tr", "en"]
    
    async def get_translation(
        self,
        key: str,
        lang: str,
        fallback: bool = True
    ) -> str:
        if translation := self.translations.get(f"{lang}.{key}"):
            return translation
        if fallback:
            for lang in self.fallback_chain:
                if translation := self.translations.get(f"{lang}.{key}"):
                    return translation
        return key
```

### Developer Tools
```python
# debug_toolkit.py
class DebugToolkit:
    def __init__(self):
        self.profiler = cProfile.Profile()
        self.debugger = pdb.Pdb()
    
    def profile_function(self, func: Callable):
        def wrapper(*args, **kwargs):
            self.profiler.enable()
            result = func(*args, **kwargs)
            self.profiler.disable()
            return result
        return wrapper
```

## Implementation Priority

1. **Phase 1 - Foundation** (1-2 months)
   - Service containerization
   - Basic monitoring
   - API gateway setup
   - Security enhancements

2. **Phase 2 - Scaling** (2-3 months)
   - Caching implementation
   - Database optimization
   - Event system upgrade
   - Background jobs

3. **Phase 3 - Reliability** (1-2 months)
   - Error handling
   - Testing framework
   - Audit system
   - Performance monitoring

4. **Phase 4 - Developer Experience** (1-2 months)
   - Documentation
   - Development tools
   - Translation system
   - Code organization

## Success Metrics

- **Performance**
  - Response time < 100ms for 95% of requests
  - Cache hit rate > 80%
  - Zero downtime deployments

- **Reliability**
  - 99.99% uptime
  - < 0.1% error rate
  - < 1s failover time

- **Security**
  - Zero critical vulnerabilities
  - 100% audit log coverage
  - < 1hr security incident response time

- **Development**
  - 80% test coverage
  - < 24hr PR review time
  - < 1 day developer onboarding