Gilded Rose Requirements Specification

Hi and welcome to team Gilded Rose. As you know, we are a small inn with a prime location in a prominent city ran by a friendly innkeeper named Allison. We also buy and sell only the finest goods. Unfortunately, our goods are constantly degrading in quality as they approach their sell by date.

We have a system in place that updates our inventory for us. It was developed by a no-nonsense type named Leeroy, who has moved on to new adventures. Your task is to add the new feature to our system so that we can begin selling a new category of items. First an introduction to our system:

• All items have a sell_in value which denotes the number of days we have to sell the items
• All items have a quality value which denotes how valuable the item is
• At the end of each day our system lowers both values for every item

Pretty simple, right? Well this is where it gets interesting:

• Once the sell by date has passed, quality degrades twice as fast
• The quality of an item is never negative
• "Aged Brie" actually increases in quality the older it gets
• The quality of an item is never more than 50
• "Sulfuras", being a legendary item, never has to be sold or decreases in quality
• "Backstage passes", like aged brie, increases in quality as its sell_in value approaches;
  • quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less but
  • quality drops to 0 after the concert

We have recently signed a supplier of conjured items. This requires an update to our system:

• "Conjured" items degrade in quality twice as fast as normal items

Feel free to make any changes to the update_quality method and add any new code as long as everything still works correctly. However, do not alter the Item module/struct as those belong to the goblin in the corner who will insta-rage and one-shot you as he doesn't believe in shared code ownership.

Just for clarification, an item can never have its quality increase above 50, however "Sulfuras" is a legendary item and as such its quality is 80 and it never alters.