Feat/basic strategy

src/Domain/BasicStrategy.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Domain;
+
+final class BasicStrategy
+{
+    public function decide(Hand $hand, Card $dealerCard): Decision
+    {
+        $value = $hand->value();
+        $dealerValue = $dealerCard->numericValue();
+
+        if ($hand->isSoft() && $value === 18 && $dealerValue >= 3 && $dealerValue <= 6) {
+            return Decision::Double;
+        }
+
+        if ($hand->isSoft() && $value === 17 && $dealerValue >= 3 && $dealerValue <= 6) {
+            return Decision::Double;
+        }
+
+        if ($value >= 17) {
+            return Decision::Stand;
+        }
+
+        if ($value >= 13 && $value <= 16 && $dealerValue >= 2 && $dealerValue <= 6) {
+            return Decision::Stand;
+        }
+
+        if ($value === 12 && $dealerValue >= 4 && $dealerValue <= 6) {
+            return Decision::Stand;
+        }
+
+        if ($value === 11 && $dealerValue >= 2 && $dealerValue <= 10) {
+            return Decision::Double;
+        }
+
+        if ($value === 10 && $dealerValue >= 2 && $dealerValue <= 9) {
+            return Decision::Double;
+        }
+
+        if ($value === 9 && $dealerValue >= 3 && $dealerValue <= 6) {
+            return Decision::Double;
+        }
+
+        return Decision::Hit;
+    }
+}

src/Domain/Decision.php

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+<?php
+
+namespace App\Domain;
+
+enum Decision
+{
+    case Hit;
+    case Stand;
+    case Double;
+    case Split;
+}

tests/Domain/BasicStrategyTest.php

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+<?php
+
+namespace App\Tests\Domain;
+
+use App\Domain\BasicStrategy;
+use App\Domain\Card;
+use App\Domain\Decision;
+use App\Domain\Hand;
+use PHPUnit\Framework\TestCase;
+
+final class BasicStrategyTest extends TestCase
+{
+    public function testHard16AgainstDealerTenShouldHit(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('9', 'Hearts'));
+        $hand->addCard(new Card('7', 'Spades'));
+
+        $dealerCard = new Card('10', 'Diamonds');
+
+        $this->assertSame(Decision::Hit, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testHard17ShouldStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('King', 'Hearts'));
+        $hand->addCard(new Card('7', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
+    public function testHard12AgainstDealer4ShouldStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('7', 'Hearts'));
+        $hand->addCard(new Card('5', 'Spades'));
+
+        $dealerCard = new Card('4', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testHard13AgainstDealer2ShouldStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('7', 'Hearts'));
+        $hand->addCard(new Card('6', 'Spades'));
+
+        $dealerCard = new Card('2', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testHard11AgainstDealer6ShouldDouble(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('7', 'Hearts'));
+        $hand->addCard(new Card('4', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Double, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testHard10AgainstDealer5ShouldDouble(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('6', 'Hearts'));
+        $hand->addCard(new Card('4', 'Spades'));
+
+        $dealerCard = new Card('5', 'Diamonds');
+
+        $this->assertSame(Decision::Double, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testHard9AgainstDealer3ShouldDouble(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('5', 'Hearts'));
+        $hand->addCard(new Card('4', 'Spades'));
+
+        $dealerCard = new Card('3', 'Diamonds');
+
+        $this->assertSame(Decision::Double, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testSoft18AgainstDealer5ShouldDouble(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('Ace', 'Hearts'));
+        $hand->addCard(new Card('7', 'Spades'));
+
+        $dealerCard = new Card('5', 'Diamonds');
+
+        $this->assertSame(Decision::Double, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testSoft18AgainstDealer2ShouldStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('Ace', 'Hearts'));
+        $hand->addCard(new Card('7', 'Spades'));
+
+        $dealerCard = new Card('2', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testSoft17AgainstDealer4ShouldDouble(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('Ace', 'Hearts'));
+        $hand->addCard(new Card('6', 'Spades'));
+
+        $dealerCard = new Card('4', 'Diamonds');
+
+        $this->assertSame(Decision::Double, $strategy->decide($hand, $dealerCard));
+    }
+
+    public function testSoft19ShouldAlwaysStand(): void
+    {
+        $strategy = new BasicStrategy();
+
+        $hand = new Hand();
+        $hand->addCard(new Card('Ace', 'Hearts'));
+        $hand->addCard(new Card('8', 'Spades'));
+
+        $dealerCard = new Card('6', 'Diamonds');
+
+        $this->assertSame(Decision::Stand, $strategy->decide($hand, $dealerCard));
+    }
+}