Bowling

README.md

@@ -6,6 +6,7 @@ Includes:
 
 - **Anagrams**: select an anagram for a word from a list of condidates.
 - **Bob**: returns different responses based on input.
+- **Bowling**: calculate the score for a game of bowling.
 - **Grade School**: given students' names along with the grade that they are in, create a roster for the school.
 - **Roman numerals**: convert a number into its roman numeral value.
 

src/BowlingGame.php

@@ -0,0 +1,88 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App;
+
+use Assert\Assert;
+use Tightenco\Collect\Support\Collection;
+
+final class BowlingGame
+{
+    private const MAX_PINS_PER_FRAME = 10;
+    private const NUMBER_OF_FRAMES = 10;
+
+    private Collection $rolls;
+
+    public function __construct()
+    {
+        $this->rolls = new Collection();
+    }
+
+    public function roll(int $pins): void
+    {
+        Assert::that($pins)
+            ->greaterOrEqualThan(0,
+                'You cannot knock down a negative number of pins. Knocked down %d.')
+            ->lessOrEqualThan(self::MAX_PINS_PER_FRAME,
+                'You can only knock down a maximum of 10 pins in a roll. Knocked down 12.');
+
+        $this->rolls->push($pins);
+    }
+
+    public function getScore(): int
+    {
+        $score = 0;
+        $roll = 0;
+
+        foreach (range(1, self::NUMBER_OF_FRAMES) as $frame) {
+            if ($this->isStrike($roll)) {
+                $score += $this->rolls[$roll];
+                $score += $this->bonusForStrike($roll);
+
+                $roll += 1;
+                continue;
+            }
+
+            if ($this->isSpare($roll)) {
+                $score += $this->defaultFrameScore($roll);
+                $score += $this->bonusForSpare($roll);
+
+                $roll += 2;
+                continue;
+            }
+
+            $score += $this->defaultFrameScore($roll);
+
+            $roll += 2;
+        }
+
+        return $score;
+    }
+
+    private function bonusForSpare(int $roll): int
+    {
+        return $this->rolls->get($roll + 2);
+    }
+
+    private function bonusForStrike(int $roll): int
+    {
+        return $this->rolls[$roll + 1] + $this->rolls[$roll + 2];
+    }
+
+    private function defaultFrameScore(int $roll): int
+    {
+        return $this->rolls[$roll] + $this->rolls[$roll + 1];
+    }
+
+    private function isSpare(int $roll): bool
+    {
+        return $this->defaultFrameScore($roll)
+            == self::MAX_PINS_PER_FRAME;
+    }
+
+    private function isStrike(int $roll): bool
+    {
+        return $this->rolls[$roll] == self::MAX_PINS_PER_FRAME;
+    }
+}

tests/BowlingGameTest.php

@@ -0,0 +1,134 @@
+<?php
+
+declare(strict_types=1);
+
+use App\BowlingGame;
+use Assert\Assert;
+use Assert\AssertionFailedException;
+
+beforeEach(function (): void {
+   $this->game = new BowlingGame();
+});
+
+it('counts an empty game', function (): void {
+    foreach (range(1, 20) as $roll) {
+        $this->game->roll(0);
+    }
+
+    assertSame(0, $this->game->getScore());
+});
+
+it('counts all single pins', function (): void {
+    foreach (range(1, 20) as $roll) {
+        $this->game->roll(1);
+    }
+
+    assertSame(20, $this->game->getScore());
+});
+
+it('adds a roll one bonus for a spare', function (): void {
+    $this->game->roll(5);
+    $this->game->roll(5); // Spare
+
+    $this->game->roll(2);
+
+    foreach (range(1, 17) as $roll) {
+        $this->game->roll(0);
+    }
+
+    assertSame(14, $this->game->getScore());
+});
+
+it('adds a two roll bonus for a strike', function (): void {
+   $this->game->roll(10); // Strike
+
+   $this->game->roll(3);
+   $this->game->roll(6);
+
+   foreach (range(1, 16) as $roll) {
+       $this->game->roll(0);
+   }
+
+   assertSame(28, $this->game->getScore());
+});
+
+it('adds an extra ball for a spare on the final frame', function (): void {
+   foreach (range(1, 18) as $roll) {
+       $this->game->roll(0);
+   }
+
+   $this->game->roll(7);
+   $this->game->roll(3); // Spare
+
+   $this->game->roll(5);
+
+   assertSame(15, $this->game->getScore());
+});
+
+it('adds an two extra balls for a strike on the final frame', function (): void {
+   foreach (range(1, 18) as $roll) {
+       $this->game->roll(0);
+   }
+
+   $this->game->roll(10); // Strike
+
+   $this->game->roll(4);
+   $this->game->roll(2);
+
+   assertSame(16, $this->game->getScore());
+});
+
+it('scores a perfect game', function (): void {
+    foreach (range(1, 12) as $roll) {
+        $this->game->roll(10);
+    }
+
+    assertSame(300, $this->game->getScore());
+});
+
+it('scores a normal game', function (): void {
+    $this->game->roll(4);
+    $this->game->roll(3);
+
+    $this->game->roll(10);
+
+    $this->game->roll(4);
+    $this->game->roll(1);
+
+    $this->game->roll(0);
+    $this->game->roll(2);
+
+    $this->game->roll(3);
+    $this->game->roll(7);
+
+    $this->game->roll(8);
+    $this->game->roll(1);
+
+    $this->game->roll(10);
+
+    $this->game->roll(0);
+    $this->game->roll(7);
+
+    $this->game->roll(1);
+    $this->game->roll(5);
+
+    $this->game->roll(10);
+    $this->game->roll(6);
+    $this->game->roll(1);
+
+    assertSame(103, $this->game->getScore());
+});
+
+it('cannot knock down a negative pins', function (): void {
+    $this->game->roll(-1);
+})->throws(
+    AssertionFailedException::class,
+    'You cannot knock down a negative number of pins. Knocked down -1.'
+);
+
+it('cannot knock down more than 10 pins in a roll', function (): void {
+    $this->game->roll(12);
+})->throws(
+    AssertionFailedException::class,
+    'You can only knock down a maximum of 10 pins in a roll. Knocked down 12.'
+);