- Code Refactoring

swift/Sources/GildedRose/CustomisedItemFactory.swift

@@ -8,10 +8,12 @@
 import Foundation
 
 protocol CustomisedItem {
+    var item: Item {get set}
     func updateItemState()
 }
 
 class CustomisedItemFactory {
+    // Returns the Customised Item based on the Item name
      func getCustomisedItem(item: Item) -> CustomisedItem {
         switch item.name {
         case ItemNameConstants.kAgedBrieItem:

swift/Sources/GildedRose/ItemQualityUpdater.swift

@@ -7,8 +7,7 @@
 
 import Foundation
 
-protocol ItemQualityUpdater {
-    var item: Item {get set}
+protocol ItemQualityUpdater: CustomisedItem {
 }
 
 extension ItemQualityUpdater {
@@ -32,3 +31,6 @@ extension ItemQualityUpdater {
         item.quality = value
     }
 }
+
+typealias ItemStateUpdater = ItemSellInUpdater & ItemQualityUpdater
+

swift/Sources/GildedRose/ItemSellInUpdater.swift

@@ -7,8 +7,7 @@
 
 import Foundation
 
-protocol ItemSellInUpdater {
-    var item: Item { get set }
+protocol ItemSellInUpdater: CustomisedItem{
     func reduceSellInDays(by days: Int)
 }
 

swift/Sources/GildedRose/Items/AgedBrieItem.swift

@@ -7,15 +7,15 @@
 
 import Foundation
 
-struct AgedBrieItem: CustomisedItem, ItemSellInUpdater, ItemQualityUpdater {
+struct AgedBrieItem: ItemStateUpdater{
     var item: Item
-    
+        
     public init(item: Item) {
         self.item = item
     }
     
     func updateItemState() {
-        // update the sell in days
+        // update the sell in days. Reduce the Sell In days by 1
         reduceSellInDays(by: 1)
         
         // Increment the Item quality by 1 if the quality is less than 50

swift/Sources/GildedRose/Items/BackstagePassesItem.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-struct BackstagePassesItem: CustomisedItem, ItemQualityUpdater, ItemSellInUpdater {
+struct BackstagePassesItem: ItemStateUpdater {
     var item: Item
     
     public init(item: Item) {
@@ -15,23 +15,26 @@ struct BackstagePassesItem: CustomisedItem, ItemQualityUpdater, ItemSellInUpdate
     }
     
     func updateItemState() {
+        // Reduce the Sell in days by 1
         reduceSellInDays(by: 1)
         
+        // If the sell in date id passed, sets the quality of item to 0
         guard !isSellInDatePassed else {
             setItemQuality(to: ValueConstants.kLowestQualityValue)
             return
         }
+        // If the Quality of item is above 50, return
         guard isItemUnderHighestQuality else {
             setItemQuality(to: ValueConstants.kHightestQualityValue)
             return
         }
         switch item.sellIn {
         case 10...:
-            increaseItemQuality(by: 1)
+            increaseItemQuality(by: 1) // If the sell in days is more than 10, increase quality by 1
         case 5..<10:
-            increaseItemQuality(by: 2)
+            increaseItemQuality(by: 2) // If sell in days is between 5 and 10, increase quality by 2
         case 0..<5:
-            increaseItemQuality(by: 3)
+            increaseItemQuality(by: 3) // If sell in days is between 0 and 5, increase quality by 3
         default:
             break
         }

swift/Sources/GildedRose/Items/StandardItem.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-struct StandardItem: CustomisedItem, ItemQualityUpdater, ItemSellInUpdater {
+struct StandardItem: ItemStateUpdater {
     var item: Item
     
     public init(item: Item) {
@@ -18,9 +18,11 @@ struct StandardItem: CustomisedItem, ItemQualityUpdater, ItemSellInUpdater {
         // Reduce the sellIn days for Item by 1
         reduceSellInDays(by: 1)
 
-        // Reduce the item quality by 1 , if the sell in date is passed decrement by 2
+        // Reduce the item quality by 1 , if the sell in date is passed decrement by double the value
         isSellInDatePassed ? reduceItemQuality(by: decreasingValueForZeroOrLessDaysToSell()) : reduceItemQuality(by: decreasingValueOverZeroDaysToSell())
+        
         guard isItemMoreThanLowestQuality else {
+            // Sets the quality to zero if the quality is negative
             setItemQuality(to: ValueConstants.kLowestQualityValue)
             return
         }

swift/Sources/GildedRose/Items/SulfurasItem.swift

@@ -15,5 +15,6 @@ struct SulfurasItem: CustomisedItem {
     }
     func updateItemState() {
         // No code as there is no change in quality or sell in days of sulfuras item
+        return
     }
 }