From d0cb683b03454afc830e5bc37af9633753757cbf Mon Sep 17 00:00:00 2001
From: Murat Bataray <murat.bataray@crelan.be>
Date: Thu, 9 Feb 2023 23:42:39 +0100
Subject: [PATCH] Extracted range checks and added helper methods + constants

---
 swift/Sources/GildedRose/GildedRose.swift | 99 ++++++++++++-----------
 1 file changed, 53 insertions(+), 46 deletions(-)

diff --git a/swift/Sources/GildedRose/GildedRose.swift b/swift/Sources/GildedRose/GildedRose.swift
index ea0aa861..6ce65fdf 100644
--- a/swift/Sources/GildedRose/GildedRose.swift
+++ b/swift/Sources/GildedRose/GildedRose.swift
@@ -1,59 +1,66 @@
+import Foundation
+
 public class GildedRose {
+    private static let agedBrieString = "Aged Brie"
+    private static let backstagePassString = "Backstage passes to a TAFKAL80ETC concert"
+    private static let sulfurasString = "Sulfuras, Hand of Ragnaros"
+    
+    private static let itemQualityDegradationAmount = -1
+    private static let minimumQuality = 0
+    private static let maximumQuality = 50
+    
     var items: [Item]
 
     public init(items: [Item]) {
         self.items = items
     }
+    
+    private func adjustQuality(_ item: Item, adjustment: Int) {
+        let adjustedQuality = item.quality + adjustment
+        if adjustedQuality <= GildedRose.maximumQuality && adjustedQuality >= GildedRose.minimumQuality {
+            item.quality += adjustment
+        }
+    }
 
-    public func updateQuality() {
-        for i in 0 ..< items.count {
-            if items[i].name != "Aged Brie", items[i].name != "Backstage passes to a TAFKAL80ETC concert" {
-                if items[i].quality > 0 {
-                    if items[i].name != "Sulfuras, Hand of Ragnaros" {
-                        items[i].quality = items[i].quality - 1
-                    }
-                }
-            } else {
-                if items[i].quality < 50 {
-                    items[i].quality = items[i].quality + 1
-
-                    if items[i].name == "Backstage passes to a TAFKAL80ETC concert" {
-                        if items[i].sellIn < 11 {
-                            if items[i].quality < 50 {
-                                items[i].quality = items[i].quality + 1
-                            }
-                        }
-
-                        if items[i].sellIn < 6 {
-                            if items[i].quality < 50 {
-                                items[i].quality = items[i].quality + 1
-                            }
-                        }
-                    }
-                }
+    private func updateItemQuality(_ item: Item) {
+        if item.name != GildedRose.agedBrieString, item.name != GildedRose.backstagePassString {
+            if item.name != GildedRose.sulfurasString {
+                self.adjustQuality(item, adjustment: item.name.lowercased().range(of: "conjured") != nil ? GildedRose.itemQualityDegradationAmount * 2 : GildedRose.itemQualityDegradationAmount)
             }
-
-            if items[i].name != "Sulfuras, Hand of Ragnaros" {
-                items[i].sellIn = items[i].sellIn - 1
-            }
-
-            if items[i].sellIn < 0 {
-                if items[i].name != "Aged Brie" {
-                    if items[i].name != "Backstage passes to a TAFKAL80ETC concert" {
-                        if items[i].quality > 0 {
-                            if items[i].name != "Sulfuras, Hand of Ragnaros" {
-                                items[i].quality = items[i].quality - 1
-                            }
-                        }
-                    } else {
-                        items[i].quality = items[i].quality - items[i].quality
-                    }
-                } else {
-                    if items[i].quality < 50 {
-                        items[i].quality = items[i].quality + 1
-                    }
+        } else {
+            self.adjustQuality(item, adjustment: 1)
+            
+            if item.name == GildedRose.backstagePassString {
+                if item.sellIn < 11 {
+                    self.adjustQuality(item, adjustment: 1)
+                }
+                
+                if item.sellIn < 6 {
+                    self.adjustQuality(item, adjustment: 1)
                 }
             }
         }
+        if item.name != GildedRose.sulfurasString {
+            item.sellIn = item.sellIn - 1
+        }
+        if item.sellIn < 0 {
+            if item.name != GildedRose.agedBrieString {
+                if item.name != GildedRose.backstagePassString {
+                    if item.name != GildedRose.sulfurasString {
+                        self.adjustQuality(item, adjustment: item.name.lowercased().range(of: "conjured") != nil ? GildedRose.itemQualityDegradationAmount * 2 : GildedRose.itemQualityDegradationAmount)
+                    }
+                } else {
+                    self.adjustQuality(item, adjustment: -item.quality)
+                }
+            } else {
+                self.adjustQuality(item, adjustment: 1)
+            }
+        }
+    }
+    
+    public func updateQuality() {
+        items.forEach({ item in
+            updateItemQuality(item)
+        })
     }
 }