diff --git a/php/src/GildedRose.php b/php/src/GildedRose.php
index cfb7f78a..5b65330c 100644
--- a/php/src/GildedRose.php
+++ b/php/src/GildedRose.php
@@ -6,11 +6,21 @@ namespace GildedRose;
 
 final class GildedRose
 {
+    private const AGED_BRIE = 'Aged Brie';
+    private const BACKSTAGE = 'Backstage passes to a TAFKAL80ETC concert';
+    private const SHR = 'Sulfuras, Hand of Ragnaros';
+
+    private const MAX_THRESHOLD = 50;
+    private const MIN_THRESHOLD = 0;
+
     /**
      * @var Item[]
      */
-    private $items;
+    private array $items;
 
+    /**
+     * @param array $items
+     */
     public function __construct(array $items)
     {
         $this->items = $items;
@@ -19,51 +29,72 @@ final class GildedRose
     public function updateQuality(): void
     {
         foreach ($this->items as $item) {
-            if ($item->name != 'Aged Brie' and $item->name != 'Backstage passes to a TAFKAL80ETC concert') {
-                if ($item->quality > 0) {
-                    if ($item->name != 'Sulfuras, Hand of Ragnaros') {
-                        $item->quality = $item->quality - 1;
+            if (!$this->isLegendaryItem($item)) {
+                $item->quality = $this->subtractQuality($item);
+            }
+
+            if ($this->qualityIncreases($item)) {
+                $item->quality = $this->addQuality($item);
+
+                if ($item->name === self::BACKSTAGE) {
+                    if ($item->sell_in <= 10) {
+                        $item->quality = $this->addQuality($item);
                     }
-                }
-            } else {
-                if ($item->quality < 50) {
-                    $item->quality = $item->quality + 1;
-                    if ($item->name == 'Backstage passes to a TAFKAL80ETC concert') {
-                        if ($item->sell_in < 11) {
-                            if ($item->quality < 50) {
-                                $item->quality = $item->quality + 1;
-                            }
-                        }
-                        if ($item->sell_in < 6) {
-                            if ($item->quality < 50) {
-                                $item->quality = $item->quality + 1;
-                            }
-                        }
+                    if ($item->sell_in <= 5) {
+                        $item->quality = $this->addQuality($item);
                     }
                 }
             }
 
-            if ($item->name != 'Sulfuras, Hand of Ragnaros') {
-                $item->sell_in = $item->sell_in - 1;
+            if (!$this->isLegendaryItem($item)) {
+                $item->sell_in = --$item->sell_in;
             }
 
-            if ($item->sell_in < 0) {
-                if ($item->name != 'Aged Brie') {
-                    if ($item->name != 'Backstage passes to a TAFKAL80ETC concert') {
-                        if ($item->quality > 0) {
-                            if ($item->name != 'Sulfuras, Hand of Ragnaros') {
-                                $item->quality = $item->quality - 1;
-                            }
-                        }
-                    } else {
-                        $item->quality = $item->quality - $item->quality;
-                    }
-                } else {
-                    if ($item->quality < 50) {
-                        $item->quality = $item->quality + 1;
-                    }
+            if ($this->sellDateReached($item)) {
+                if ($item->name === self::AGED_BRIE) {
+                    $item->quality = $this->addQuality($item);
+                    continue;
+                }
+
+                if ($item->name === self::BACKSTAGE) {
+                    // Quality of backstage passes drops to 0 when sell date has been reached
+                    $item->quality = 0;
+                    continue;
+                }
+
+                if (!$this->isLegendaryItem($item)) {
+                    $item->quality = $this->subtractQuality($item);
                 }
             }
         }
     }
+
+    private function qualityIncreases(Item $item): bool
+    {
+        return in_array($item->name, [self::AGED_BRIE, self::BACKSTAGE]);
+    }
+
+    private function isLegendaryItem(Item $item): bool
+    {
+        return $item->name === self::SHR;
+    }
+
+    private function sellDateReached(Item $item): bool
+    {
+        return $item->sell_in < 0;
+    }
+
+    private function subtractQuality(Item $item): int
+    {
+        $quality = $item->quality;
+
+        return $quality > self::MIN_THRESHOLD ? --$quality : $quality;
+    }
+
+    private function addQuality(Item $item): int
+    {
+        $quality = $item->quality;
+
+        return $quality < self::MAX_THRESHOLD ? ++$quality : $quality;
+    }
 }
diff --git a/php/tests/GildedRoseTest.php b/php/tests/GildedRoseTest.php
index 52e7ddc6..e7f97887 100644
--- a/php/tests/GildedRoseTest.php
+++ b/php/tests/GildedRoseTest.php
@@ -12,9 +12,23 @@ class GildedRoseTest extends TestCase
 {
     public function testFoo(): void
     {
-        $items = [new Item('foo', 0, 0)];
+        $items = [
+            new Item('+5 Dexterity Vest', 10, 20),
+            new Item('Aged Brie', 2, 0),
+            new Item('Sulfuras, Hand of Ragnaros', 0, 80),
+        ];
+
         $gildedRose = new GildedRose($items);
+
         $gildedRose->updateQuality();
-        $this->assertSame('fixme', $items[0]->name);
+
+        $this->assertSame(9, $items[0]->sell_in);
+        $this->assertSame(19, $items[0]->quality);
+
+        $this->assertSame(1, $items[1]->sell_in);
+        $this->assertSame(1, $items[1]->quality);
+
+        $this->assertSame(0, $items[2]->sell_in);
+        $this->assertSame(80, $items[2]->quality);
     }
 }