code-archaeologist

# Codebase Evolution Analysis: E-Commerce Platform (2015-2023)

## Key Architectural Changes

### 2017: Microservices Transition
- **Change**: Monolithic architecture split into microservices
- **Motivation**: Scalability issues with increasing user base
- **Code Example**:
```python
# Original monolithic service
class OrderService:
    def __init__(self):
        self.inventory = InventoryService()
        self.payment = PaymentService()
```

### 2019: Introduction of Event Sourcing
- **Change**: Event-driven architecture implemented
- **Motivation**: Need for better audit trails and data consistency
- **Code Example**:
```python
# Event sourcing implementation
class OrderEventHandler:
    def handle_order_created(self, event):
        # Process order creation event
        self.publish_event('OrderCreatedEvent', event)
```

## Major Refactoring Efforts

### 2020: Payment Processing Refactor
- **Reason**: PCI compliance requirements
- **Impact**: 3-week downtime for payment subsystem

## Technical Debt Accumulation

### 2018: Legacy Payment Gateway Integration
- **Debt**: Tight coupling with obsolete payment provider
- **Consequence**: Increased maintenance costs and migration challenges

## Evolution Timeline

1. **2015**: Initial monolithic architecture
2. **2017**: Microservices transition begins
3. **2019**: Event sourcing implemented
4. **2020**: Payment processing refactor
5. **2022**: Migration to cloud-native infrastructure