Refactored GildedRose

Signed-off-by: Atul Anand <atulanand206@gmail.com>

scala/src/main/scala/com/gildedrose/GildedRose.scala

@@ -2,57 +2,106 @@ package com.gildedrose
 
 class GildedRose(val items: Array[Item]) {
 
-
   def updateQuality() {
-    for (i <- 0 until items.length) {
-      if (!items(i).name.equals("Aged Brie")
-        && !items(i).name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-        if (items(i).quality > 0) {
-          if (!items(i).name.equals("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.equals("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
-              }
-            }
-          }
-        }
-      }
-
-      if (!items(i).name.equals("Sulfuras, Hand of Ragnaros")) {
-        items(i).sellIn = items(i).sellIn - 1
-      }
-
-      if (items(i).sellIn < 0) {
-        if (!items(i).name.equals("Aged Brie")) {
-          if (!items(i).name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-            if (items(i).quality > 0) {
-              if (!items(i).name.equals("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
-          }
-        }
-      }
+    for (i <- items.indices) {
+      if (isItemNotIncremental(i)) {
+        if (isQualityPositive(i))
+          incrementQuality(i, -1)
+      } else
+        incrementQualityForIncrementalItems(i)
+      decrementSellInIfNotSulfuras(i)
+      if (isSellInLessThanThreshold(i, 0))
+        updateQualityIfSellInZero(i)
     }
   }
+
+  private def incrementQualityForIncrementalItems(i: Int): Unit = {
+    if (isQualityLessThan50(i)) {
+      incrementQuality(i, 1)
+      additionalIncrementForBackstagePasses(i)
+    }
+  }
+
+  private def updateQualityIfSellInZero(i: Int): Unit = {
+    if (isAgedBrie(i))
+      incrementQualityBy1IfLessThan50(i)
+    else if (isBackstagePass(i))
+      dropQualityTo0(i)
+    else if (!isSulfuras(i) && isQualityPositive(i))
+      incrementQuality(i, -1)
+  }
+
+  private def additionalIncrementForBackstagePasses(i: Int): Unit = {
+    if (isBackstagePass(i))
+      incrementBackstagePassQuality(i)
+  }
+
+  private def incrementBackstagePassQuality(i: Int): Unit = {
+    incrementForBackstagePassesIfSellInBetween5and10(i)
+    incrementForBackstagePassesIfSellInBetween0and5(i)
+  }
+
+  private def incrementForBackstagePassesIfSellInBetween0and5(i: Int): Unit = {
+    if (isSellInLessThanThreshold(i, 6))
+      incrementQualityBy1IfLessThan50(i)
+  }
+
+  private def incrementForBackstagePassesIfSellInBetween5and10(i: Int): Unit = {
+    if (isSellInLessThanThreshold(i, 11))
+      incrementQualityBy1IfLessThan50(i)
+  }
+
+  private def decrementSellInIfNotSulfuras(i: Int): Unit = {
+    if (!isSulfuras(i))
+      decrementSellIn(i)
+  }
+
+  private def incrementQualityBy1IfLessThan50(i: Int): Unit = {
+    if (isQualityLessThan50(i))
+      incrementQuality(i, 1)
+  }
+
+  private def isSellInLessThanThreshold(i: Int, threshold: Int) = {
+    items(i).sellIn < threshold
+  }
+
+  private def decrementSellIn(i: Int): Unit = {
+    items(i).sellIn = items(i).sellIn - 1
+  }
+
+  private def isQualityPositive(i: Int) = {
+    items(i).quality > 0
+  }
+
+  private def isQualityLessThan50(i: Int) = {
+    items(i).quality < 50
+  }
+
+  private def incrementQuality(i: Int, delta: Int): Unit = {
+    items(i).quality = items(i).quality + delta
+  }
+
+  private def dropQualityTo0(i: Int): Unit = {
+    items(i).quality = 0
+  }
+
+  private def isItemNotIncremental(i: Int) = {
+    !isAgedBrie(i) && !isBackstagePass(i) && !isSulfuras(i)
+  }
+
+  private def isBackstagePass(i: Int) = {
+    items(i).name.equals("Backstage passes to a TAFKAL80ETC concert")
+  }
+
+  private def isAgedBrie(i: Int) = {
+    items(i).name.equals("Aged Brie")
+  }
+
+  private def isSulfuras(i: Int) = {
+    items(i).name.equals("Sulfuras, Hand of Ragnaros")
+  }
+
+  private def isConjured(i: Int) = {
+    items(i).name.equals("Conjured Mana Cake")
+  }
 }