GildedRose-Refactoring-Kata/python/Design_Explanation.txt

GILDED ROSE REFACTORING - DESIGN EXPLANATION

MAJOR ISSUES IN ORIGINAL CODE:
The original code has a complex structure of nested if-statements (7+ levels) that check item names 
repeatedly in the update_quality() method. This is a nightmare to maintain and does not follow the Open/Closed Principle, 
as adding a new item type ("Conjured") means modifying existing code and possibly breaking it. 
The entire business logic is packed into a single 50-line method with no encapsulation, 
making it hard to test the behavior of individual items or trace the code execution.

DESIGN SOLUTION - STRATEGY PATTERN:
I applied the Strategy Pattern to move the update logic for each item type into a separate 
strategy class: NormalItemStrategy, AgedBrieStrategy, SulfurasStrategy, BackstagePassStrategy, and ConjuredItemStrategy. 
The GildedRose class holds a dictionary of item names to their corresponding strategies and calls the update strategy accordingly. 
This design is SOLID, with a focus on Single Responsibility (each class has one task) 
and Open/Closed (adding new item types means implementing new strategy classes without changing existing code).

HOW THIS SOLVES THE PROBLEMS:
The Strategy Pattern completely eliminates the need for nested conditionals. 
Each strategy class is simple, clean, and handles only one type of item. The addition of the Conjured item feature 
requires nothing more than creating the ConjuredItemStrategy class without modifying any existing code.

POTENTIAL DRAWBACKS:
The Strategy Pattern requires increasing the number of classes from 2 to 8. 
While this may be overkill for such a small number of item types, it does give us excellent scalability should 
additional item types be added in the future. It does introduce a slight complexity due to the need for a dictionary
to select which strategy to use. There is a slight performance hit due to object creation.