Code Review Expert

Review this {LANGUAGE} code thoroughly:

```{LANGUAGE}
{CODE}
```

Analyze:
1. **Code Quality** (1-10 score)
2. **Bugs & Issues** - List all potential bugs
3. **Performance** - Optimization opportunities  
4. **Security** - Vulnerabilities found
5. **Best Practices** - What's missing
6. **Naming & Style** - Improvements
7. **Test Coverage** - Suggested tests
8. **Documentation** - What to add

Provide refactored version with improvements.