Changes to Goods, PriceList and Market

src/Bread.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types=1);
+
+namespace ClansOfCaledonia;
+
+final class Bread extends Good
+{
+
+}

src/Cheese.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types=1);
+
+namespace ClansOfCaledonia;
+
+final class Cheese extends Good
+{
+
+}

src/Good.php

@@ -3,13 +3,4 @@
 
 abstract class Good
 {
-    public static function milk(): self
-    {
-        return new Milk;
-    }
-
-    public function isMilk(): bool
-    {
-        return false;
-    }
 }

src/Grain.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types=1);
+
+namespace ClansOfCaledonia;
+
+final class Grain extends Good
+{
+
+}

src/Market.php

@@ -3,16 +3,38 @@
 
 final class Market
 {
-    public function priceFor(Good $milk): Pound
+    /** @var PriceListCollection */
+    private $priceListCollection;
+
+    public function __construct(PriceListCollection $priceListCollection)
+    {
+        $this->priceListCollection = $priceListCollection;
+    }
+
+    public function priceFor(Good $good): Pound
     {
-        return new Pound(5);
+        return $this->priceListCollection->currentFor($good);
     }
 
     public function sellTo(Offer $offer): Pound
     {
-        return new Pound(
-            $offer->amount()->amount() *
-            $this->priceFor($offer->good())->amount()
-        );
+        $cost = $this
+            ->priceFor($offer->good())
+            ->mult($offer->amount()->amount());
+
+        $this->priceListCollection->moveFor($offer->good(), -$offer->amount()->amount());
+
+        return $cost;
+    }
+
+    public function buyFrom(Offer $offer): Pound
+    {
+        $cost = $this
+            ->priceFor($offer->good())
+            ->mult($offer->amount()->amount());
+
+        $this->priceListCollection->moveFor($offer->good(), $offer->amount()->amount());
+
+        return $cost;
     }
 }

src/Milk.php

@@ -3,8 +3,4 @@
 
 final class Milk extends Good
 {
-    public function isMilk(): bool
-    {
-        return true;
-    }
 }

src/Pound.php

@@ -17,4 +17,9 @@ public function amount(): int
     {
         return $this->amount;
     }
+
+    public function mult(int $multiplier): Pound
+    {
+        return new Pound($this->amount * $multiplier);
+    }
 }

src/PriceList.php

@@ -30,4 +30,25 @@ public function current(): Pound
     {
         return $this->prices[$this->position];
     }
+
+    public function move(int $positions): Pound
+    {
+        $nextPosition = $this->position + $positions;
+
+        if ($nextPosition >= count($this->prices)) {
+            $this->position = count($this->prices) - 1;
+
+            return $this->current();
+        }
+
+        if ($nextPosition < 0) {
+            $this->position = 0;
+
+            return $this->current();
+        }
+
+        $this->position = $nextPosition;
+
+        return $this->current();
+    }
 }

src/PriceListBuilder.php

@@ -15,7 +15,87 @@ public function milkPrices(): PriceList
             new Pound(7),
             new Pound(7),
             new Pound(8),
-            new Pound(8)
+            new Pound(8),
         );
     }
+
+    public function woolPrices(): PriceList
+    {
+        return PriceList::fromList(
+            new Pound(3),
+            new Pound(3),
+            new Pound(4),
+            new Pound(4),
+            new Pound(5),
+            new Pound(5),
+            new Pound(6),
+            new Pound(6),
+            new Pound(7),
+            new Pound(8),
+        );
+    }
+
+    public function grainPrices(): PriceList
+    {
+        return PriceList::fromList(
+            new Pound(3),
+            new Pound(3),
+            new Pound(4),
+            new Pound(5),
+            new Pound(6),
+            new Pound(6),
+            new Pound(7),
+            new Pound(7),
+            new Pound(8),
+            new Pound(8),
+        );
+    }
+
+    public function breadPrices(): PriceList
+    {
+        return PriceList::fromList(
+            new Pound(7),
+            new Pound(8),
+            new Pound(9),
+            new Pound(10),
+            new Pound(11),
+            new Pound(11),
+            new Pound(12),
+            new Pound(13),
+            new Pound(14),
+            new Pound(15),
+            );
+    }
+
+    public function cheesePrices(): PriceList
+    {
+        return PriceList::fromList(
+            new Pound(7),
+            new Pound(8),
+            new Pound(9),
+            new Pound(10),
+            new Pound(11),
+            new Pound(12),
+            new Pound(13),
+            new Pound(14),
+            new Pound(14),
+            new Pound(15),
+            );
+    }
+
+    public function whiskyPrices(): PriceList
+    {
+        return PriceList::fromList(
+            new Pound(7),
+            new Pound(8),
+            new Pound(9),
+            new Pound(10),
+            new Pound(11),
+            new Pound(12),
+            new Pound(13),
+            new Pound(14),
+            new Pound(15),
+            new Pound(16),
+            );
+    }
 }

src/PriceListCollection.php

@@ -0,0 +1,44 @@
+<?php declare(strict_types=1);
+
+namespace ClansOfCaledonia;
+
+use function get_class;
+use InvalidArgumentException;
+use function sprintf;
+
+final class PriceListCollection
+{
+    /** @var PriceList[] */
+    private $priceLists;
+
+    public function __construct()
+    {
+        $this->priceLists = [];
+    }
+
+    public function registerPriceListForGood(Good $good, PriceList $priceList): void
+    {
+        $this->priceLists[get_class($good)] = $priceList;
+    }
+
+    public function currentFor(Good $good): Pound
+    {
+        $this->ensureGoodHasPriceList($good);
+
+        return $this->priceLists[get_class($good)]->current();
+    }
+
+    public function moveFor(Good $good, int $positions): Pound
+    {
+        $this->ensureGoodHasPriceList($good);
+
+        return $this->priceLists[get_class($good)]->move($positions);
+    }
+
+    private function ensureGoodHasPriceList(Good $good): void
+    {
+        if (!isset($this->priceLists[get_class($good)])) {
+            throw new InvalidArgumentException(sprintf("Good: %s is unknown", get_class($good)));
+        }
+    }
+}

src/Whisky.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types=1);
+
+namespace ClansOfCaledonia;
+
+final class Whisky extends Good
+{
+
+}

src/Wool.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types=1);
+
+namespace  ClansOfCaledonia;
+
+final class Wool extends Good
+{
+
+}

src/autoload.php

@@ -16,7 +16,9 @@ function($class) {
                 'clansofcaledonia\\pound' => '/Pound.php',
                 'clansofcaledonia\\pricelist' => '/PriceList.php',
                 'clansofcaledonia\\pricelistbuilder' => '/PriceListBuilder.php',
-                'clansofcaledonia\\unit' => '/Unit.php'
+                'clansofcaledonia\\unit' => '/Unit.php',
+                'clansofcaledonia\\pricelistcollection' => '/PriceListCollection.php',
+                'clansofcaledonia\\wool' => '/Wool.php'
             );
         }
         $cn = strtolower($class);