Add base code for Shotgun Surgery illustration

Author: Dani Santamaría

examples/php/php-step_shotgun_surgery-01_base/composer.json

@@ -27,7 +27,7 @@
         }
     ],
     "require": {
-        "php": "^7.2"
+        "php": "^7.4"
     },
     "require-dev": {
         "jakub-onderka/php-parallel-lint": "^1.0",

examples/php/php-step_shotgun_surgery-01_base/composer.lock

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Application;
+
+use CodelyTv\StepShotgunSurgery\Domain\StepDurationCalculatorFactory;
+use CodelyTv\StepShotgunSurgery\Domain\StepRepository;
+
+class GetStepDuration
+{
+    private StepRepository $steps;
+
+    public function __construct(StepRepository $steps)
+    {
+        $this->steps = $steps;
+    }
+
+    public function __invoke(string $stepId): float
+    {
+        $step = $this->steps->find($stepId);
+        return StepDurationCalculatorFactory::build()->calculate($step);
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Application/GetStepDuration.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+class DurationMultiplier
+{
+    public static function multiplierFor(Step $step): float
+    {
+        if ($step->type() === StepEnums::STEP_TYPE_VIDEO) {
+            return StepEnums::STEP_DURATION_MULTIPLIER_VIDEO;
+        }
+
+        if ($step->type() === StepEnums::STEP_TYPE_QUIZ) {
+            return StepEnums::STEP_DURATION_MULTIPLIER_QUIZ;
+        }
+
+        return 1.0;
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Codelyber.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+class Question
+{
+
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/DurationMultiplier.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+final class QuizStep extends Step
+{
+    private array $questions;
+
+    public function __construct(string $id, Question ...$questions)
+    {
+        parent::__construct($id);
+        $this->questions = $questions;
+    }
+
+    public function type(): string
+    {
+        return StepEnums::STEP_TYPE_QUIZ;
+    }
+
+    public function videoDuration(): int
+    {
+        throw new Exception('Ques doesn\'t contain any video.');
+    }
+
+    public function questionCount(): int
+    {
+        return count($this->questions);
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/Question.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+abstract class Step
+{
+    private string $id;
+
+    public function __construct(string $id)
+    {
+        $this->id = $id;
+    }
+
+    public function id(): string
+    {
+        return $this->id;
+    }
+
+    abstract function type(): string;
+
+    abstract function videoDuration(): int;
+
+    abstract function questionCount(): int;
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/QuizStep.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+interface StepDurationCalculator
+{
+    public function supports(Step $step): bool;
+
+    public function calculate(Step $step): float;
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/Step.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+class StepDurationCalculatorChain implements StepDurationCalculator
+{
+    /** @var StepDurationCalculator[] */
+    private array $calculators;
+
+    public function __construct(StepDurationCalculator ...$calculators)
+    {
+        $this->calculators = $calculators;
+    }
+
+    public function supports(Step $step): bool
+    {
+        return in_array($step->type(), StepEnums::STEP_TYPES);
+    }
+
+    public function calculate(Step $step): float
+    {
+        foreach ($this->calculators as $calculator) {
+            if ($calculator->supports($step)) {
+                return $calculator->calculate($step);
+            }
+        }
+
+        throw new RuntimeException("Missing calculator for step type {$step->type()}");
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepDurationCalculator.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+class StepDurationCalculatorFactory
+{
+    public static function build(): StepDurationCalculator
+    {
+        // Remember to add the calculator!!
+        return new StepDurationCalculatorChain(
+            new StepDurationCalculatorVideo(),
+            new StepDurationCalculatorQuiz()
+        );
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepDurationCalculatorChain.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+class StepDurationCalculatorQuiz implements StepDurationCalculator
+{
+    public function supports(Step $step): bool
+    {
+        return $step instanceof QuizStep;
+    }
+
+    public function calculate(Step $step): float
+    {
+        return $step->questionCount() * StepEnums::QUIZ_QUESTION_DURATION * DurationMultiplier::multiplierFor($step);
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepDurationCalculatorFactory.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+class StepDurationCalculatorVideo implements StepDurationCalculator
+{
+    public function supports(Step $step): bool
+    {
+        return $step instanceof VideoStep;
+    }
+
+    public function calculate(Step $step): float
+    {
+        return $step->videoDuration() * DurationMultiplier::multiplierFor($step);
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepDurationCalculatorQuiz.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+final class StepEnums
+{
+    const STEP_TYPE_VIDEO = 'video';
+    const STEP_TYPE_QUIZ = 'quiz';
+
+    const STEP_DURATION_MULTIPLIER_VIDEO = 1.1;
+    const STEP_DURATION_MULTIPLIER_QUIZ = 1.5;
+
+    const QUIZ_QUESTION_DURATION = 5;
+
+    # Important: don't forget to add here the type!!
+    const STEP_TYPES = [
+        self::STEP_TYPE_VIDEO,
+        self::STEP_TYPE_QUIZ
+    ];
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepDurationCalculatorVideo.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+interface StepRepository
+{
+    public function find(string $id): Step;
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepEnums.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CodelyTv\StepShotgunSurgery\Domain;
+
+final class VideoStep extends Step
+{
+    private int $videoDuration;
+
+    public function __construct(string $id, int $videoDuration)
+    {
+        parent::__construct($id);
+        $this->videoDuration = $videoDuration;
+    }
+
+    function type(): string
+    {
+        return StepEnums::STEP_TYPE_VIDEO;
+    }
+
+    function videoDuration(): int
+    {
+        return $this->videoDuration;
+    }
+
+    function questionCount(): int
+    {
+        throw new Exception('Video doesn\'t contain any quiz questions.');
+    }
+}

examples/php/php-step_shotgun_surgery-01_base/src/Domain/StepRepository.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace CodelyTv\StepShotgunSurgery\Tests\Application;
+
+use CodelyTv\StepShotgunSurgery\Application\GetStepDuration;
+use CodelyTv\StepShotgunSurgery\Domain\StepRepository;
+use CodelyTv\StepShotgunSurgery\Domain\VideoStep;
+use PHPUnit\Framework\TestCase;
+
+final class GetStepDurationTest extends TestCase
+{
+    /** @test */
+    public function shouldReturnVideoStepDuration()
+    {
+        $steps = $this->createMock(StepRepository::class);
+        $steps
+            ->method('find')
+            ->willReturn(new VideoStep('videoId', 10));
+
+        $getStepDuration = new GetStepDuration($steps);
+
+        $duration = $getStepDuration->__invoke('videoId');
+
+        $this->assertSame(11.0, $duration);
+    }
+}