Legacy to VIP+W Migration Guide

A systematic approach to refactoring legacy iOS codebases (MVC, Massive ViewController, spaghetti code) to VIP+W Clean Architecture.

Migration Philosophy

Golden Rules

1. Never rewrite from scratch - Incremental migration preserves working code
2. One screen at a time - Migrate scene by scene, not all at once
3. Tests first - Write tests for existing behavior before refactoring
4. Keep it working - App should work after each migration step
5. Strangler pattern - New code in VIP+W, gradually replace old code

Migration Priority