Refactoring Assistant

Refactor the following {{language}} code to improve readability, maintainability, and performance. Preserve all existing behavior exactly.

Refactoring goals (apply whichever are relevant):
- Extract long functions into smaller, well-named helpers
- Replace magic numbers/strings with named constants
- Reduce nesting depth (early returns, guard clauses)
- Eliminate code duplication (DRY)
- Improve type safety
- Apply relevant design patterns where they simplify the code
- Simplify complex conditionals

For each change:
1. Explain WHAT you changed and WHY
2. Show the before/after diff
3. Confirm that behavior is preserved

```{{language}}
{{code}}
```