From 9dc82146c91b78feccb86b07e265e6140ecd1a05 Mon Sep 17 00:00:00 2001
From: Aydin Hassan <aydin@hotmail.co.uk>
Date: Tue, 1 Dec 2020 19:21:22 +0100
Subject: [PATCH 1/2] Allow exercises to provide initial code

---
 app/config.php                            | 17 ++++--
 src/Exercise/ProvidesInitialCode.php      | 21 ++++++++
 src/Factory/MenuFactory.php               |  8 +--
 src/Listener/InitialCodeListener.php      | 46 ++++++++++++++++
 src/Solution/SingleFileSolution.php       |  4 ++
 src/Solution/SolutionFile.php             |  2 +-
 test/Asset/ExerciseWithInitialCode.php    | 53 ++++++++++++++++++
 test/Asset/initial-code/init-solution.php |  5 ++
 test/Listener/InitialCodeListenerTest.php | 66 +++++++++++++++++++++++
 9 files changed, 211 insertions(+), 11 deletions(-)
 create mode 100644 src/Exercise/ProvidesInitialCode.php
 create mode 100644 src/Listener/InitialCodeListener.php
 create mode 100644 test/Asset/ExerciseWithInitialCode.php
 create mode 100644 test/Asset/initial-code/init-solution.php
 create mode 100644 test/Listener/InitialCodeListenerTest.php

diff --git a/app/config.php b/app/config.php
index 17d0ffbb..e59ea364 100644
--- a/app/config.php
+++ b/app/config.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use Colors\Color;
+use PhpSchool\PhpWorkshop\Listener\InitialCodeListener;
 use function DI\create;
 use function DI\factory;
 use Kadet\Highlighter\KeyLighter;
@@ -201,17 +202,20 @@
     },
 
     //Listeners
-    PrepareSolutionListener::class       => create(),
-    CodePatchListener::class             => function (ContainerInterface $c) {
+    InitialCodeListener::class => function (ContainerInterface $c) {
+        return new InitialCodeListener(getcwd());
+    },
+    PrepareSolutionListener::class => create(),
+    CodePatchListener::class => function (ContainerInterface $c) {
         return new CodePatchListener($c->get(CodePatcher::class));
     },
-    SelfCheckListener::class             => function (ContainerInterface $c) {
+    SelfCheckListener::class => function (ContainerInterface $c) {
         return new SelfCheckListener($c->get(ResultAggregator::class));
     },
     CheckExerciseAssignedListener::class => function (ContainerInterface $c) {
         return new CheckExerciseAssignedListener($c->get(UserState::class));
     },
-    ConfigureCommandListener::class      => function (ContainerInterface $c) {
+    ConfigureCommandListener::class => function (ContainerInterface $c) {
         return new ConfigureCommandListener(
             $c->get(UserState::class),
             $c->get(ExerciseRepository::class),
@@ -393,5 +397,10 @@ function (CgiResult $result) use ($c) {
                 containerListener(SelfCheckListener::class)
             ],
         ],
+        'create-initial-code' => [
+            'exercise.selected' => [
+                containerListener(InitialCodeListener::class)
+            ]
+        ]
     ],
 ];
diff --git a/src/Exercise/ProvidesInitialCode.php b/src/Exercise/ProvidesInitialCode.php
new file mode 100644
index 00000000..708fb996
--- /dev/null
+++ b/src/Exercise/ProvidesInitialCode.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpSchool\PhpWorkshop\Exercise;
+
+use PhpSchool\PhpWorkshop\Solution\SolutionInterface;
+
+/**
+ * Exercises can implement this method if they want to provide some
+ * code for the user to start with, eg a failing solution.
+ */
+interface ProvidesInitialCode
+{
+    /**
+     * Get the exercise solution.
+     *
+     * @return SolutionInterface
+     */
+    public function getInitialCode(): SolutionInterface;
+}
diff --git a/src/Factory/MenuFactory.php b/src/Factory/MenuFactory.php
index 3249018d..2bc10dc2 100644
--- a/src/Factory/MenuFactory.php
+++ b/src/Factory/MenuFactory.php
@@ -146,13 +146,9 @@ private function isExerciseDisabled(ExerciseInterface $exercise, UserState $user
      */
     private function dispatchExerciseSelectedEvent(EventDispatcher $eventDispatcher, ExerciseInterface $exercise): void
     {
+        $eventDispatcher->dispatch(new Event('exercise.selected', ['exercise' => $exercise]));
         $eventDispatcher->dispatch(
-            new Event(
-                sprintf(
-                    'exercise.selected.%s',
-                    AbstractExercise::normaliseName($exercise->getName())
-                )
-            )
+            new Event(sprintf('exercise.selected.%s', AbstractExercise::normaliseName($exercise->getName())))
         );
     }
 }
diff --git a/src/Listener/InitialCodeListener.php b/src/Listener/InitialCodeListener.php
new file mode 100644
index 00000000..a7948bac
--- /dev/null
+++ b/src/Listener/InitialCodeListener.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpSchool\PhpWorkshop\Listener;
+
+use PhpSchool\PhpWorkshop\Event\Event;
+use PhpSchool\PhpWorkshop\Exercise\ProvidesInitialCode;
+use PhpSchool\PhpWorkshop\Solution\SolutionFile;
+
+/**
+ * Copy over any initial files for this exercise when
+ * it is selected in the menu - only if they do not exist already
+ *
+ * We might want to ask the user to force this if the files exist, we could also check
+ * the contents match what we expect.
+ */
+class InitialCodeListener
+{
+    /**
+     * @var string
+     */
+    private $workingDirectory;
+
+    public function __construct(string $workingDirectory)
+    {
+        $this->workingDirectory = $workingDirectory;
+    }
+
+    /**
+     * @param Event $event
+     */
+    public function __invoke(Event $event): void
+    {
+        $exercise = $event->getParameter('exercise');
+
+        if ($exercise instanceof ProvidesInitialCode) {
+            foreach ($exercise->getInitialCode()->getFiles() as $file) {
+                /** @var SolutionFile $file */
+                if (!file_exists($this->workingDirectory . '/' . $file->getRelativePath())) {
+                    copy($file->getAbsolutePath(), $this->workingDirectory . '/' . $file->getRelativePath());
+                }
+            }
+        }
+    }
+}
diff --git a/src/Solution/SingleFileSolution.php b/src/Solution/SingleFileSolution.php
index 151b9b8a..b32aac67 100644
--- a/src/Solution/SingleFileSolution.php
+++ b/src/Solution/SingleFileSolution.php
@@ -22,6 +22,10 @@ class SingleFileSolution implements SolutionInterface
      */
     public function __construct(string $file)
     {
+        if (!file_exists($file)) {
+            throw new InvalidArgumentException(sprintf('File: "%s" does not exist', $file));
+        }
+
         $this->file = SolutionFile::fromFile((string) realpath($file));
     }
 
diff --git a/src/Solution/SolutionFile.php b/src/Solution/SolutionFile.php
index fe4af028..b9a89d44 100644
--- a/src/Solution/SolutionFile.php
+++ b/src/Solution/SolutionFile.php
@@ -53,7 +53,7 @@ public static function fromFile(string $file): self
      *
      * @return string
      */
-    private function getAbsolutePath(): string
+    public function getAbsolutePath(): string
     {
         return sprintf('%s/%s', $this->baseDirectory, $this->relativePath);
     }
diff --git a/test/Asset/ExerciseWithInitialCode.php b/test/Asset/ExerciseWithInitialCode.php
new file mode 100644
index 00000000..e32a9467
--- /dev/null
+++ b/test/Asset/ExerciseWithInitialCode.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace PhpSchool\PhpWorkshopTest\Asset;
+
+use PhpSchool\PhpWorkshop\Exercise\ExerciseInterface;
+use PhpSchool\PhpWorkshop\Exercise\ExerciseType;
+use PhpSchool\PhpWorkshop\Exercise\ProvidesInitialCode;
+use PhpSchool\PhpWorkshop\ExerciseDispatcher;
+use PhpSchool\PhpWorkshop\Solution\SingleFileSolution;
+use PhpSchool\PhpWorkshop\Solution\SolutionInterface;
+
+class ExerciseWithInitialCode implements ExerciseInterface, ProvidesInitialCode
+{
+    public function getName(): string
+    {
+        // TODO: Implement getName() method.
+    }
+
+    public function getDescription(): string
+    {
+        // TODO: Implement getDescription() method.
+    }
+
+    public function getSolution(): string
+    {
+        // TODO: Implement getSolution() method.
+    }
+
+    public function getProblem(): string
+    {
+        // TODO: Implement getProblem() method.
+    }
+
+    public function tearDown(): void
+    {
+        // TODO: Implement tearDown() method.
+    }
+
+    public function getType(): ExerciseType
+    {
+        // TODO: Implement getType() method.
+    }
+
+    public function configure(ExerciseDispatcher $dispatcher): void
+    {
+        // TODO: Implement configure() method.
+    }
+
+    public function getInitialCode(): SolutionInterface
+    {
+        return SingleFileSolution::fromFile(__DIR__ . '/initial-code/init-solution.php');
+    }
+}
diff --git a/test/Asset/initial-code/init-solution.php b/test/Asset/initial-code/init-solution.php
new file mode 100644
index 00000000..b415a705
--- /dev/null
+++ b/test/Asset/initial-code/init-solution.php
@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+echo "This is an initial solution";
diff --git a/test/Listener/InitialCodeListenerTest.php b/test/Listener/InitialCodeListenerTest.php
new file mode 100644
index 00000000..18a55671
--- /dev/null
+++ b/test/Listener/InitialCodeListenerTest.php
@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpSchool\PhpWorkshopTest\Listener;
+
+use PhpSchool\PhpWorkshop\Event\Event;
+use PhpSchool\PhpWorkshop\Listener\InitialCodeListener;
+use PhpSchool\PhpWorkshopTest\Asset\CliExerciseImpl;
+use PhpSchool\PhpWorkshopTest\Asset\ExerciseWithInitialCode;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Filesystem\Filesystem;
+
+class InitialCodeListenerTest extends TestCase
+{
+    /**
+     * @var Filesystem
+     */
+    private $filesystem;
+
+    /**
+     * @var string
+     */
+    private $cwd;
+
+    public function setUp(): void
+    {
+        $this->filesystem = new Filesystem();
+
+        $this->cwd = sprintf('%s/%s', str_replace('\\', '/', sys_get_temp_dir()), $this->getName());
+        mkdir($this->cwd, 0775, true);
+    }
+
+    public function testExerciseCodeIsCopiedIfExerciseProvidesInitialCode(): void
+    {
+        $exercise = new ExerciseWithInitialCode();
+
+        $event = new Event('exercise.selected', ['exercise' => $exercise]);
+
+        $listener = new InitialCodeListener($this->cwd);
+        $listener->__invoke($event);
+
+        $this->assertFileExists($this->cwd . '/init-solution.php');
+        $this->assertFileEquals(
+            $exercise->getInitialCode()->getFiles()[0]->getAbsolutePath(),
+            $this->cwd . '/init-solution.php'
+        );
+    }
+
+    public function testExerciseCodeIsNotCopiedIfExerciseDoesNotProvideInitialCode(): void
+    {
+        $exercise = new CliExerciseImpl();
+
+        $event = new Event('exercise.selected', ['exercise' => $exercise]);
+
+        $listener = new InitialCodeListener($this->cwd);
+        $listener->__invoke($event);
+
+        $this->assertEmpty(array_diff(scandir($this->cwd), ['.', '..']));
+    }
+
+    public function tearDown(): void
+    {
+        $this->filesystem->remove($this->cwd);
+    }
+}

From d50b6425f6f5961076d32a5ef6c3449eb595bb99 Mon Sep 17 00:00:00 2001
From: Aydin Hassan <aydin@hotmail.co.uk>
Date: Tue, 1 Dec 2020 19:56:17 +0100
Subject: [PATCH 2/2] Return early

---
 src/Listener/InitialCodeListener.php | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/Listener/InitialCodeListener.php b/src/Listener/InitialCodeListener.php
index a7948bac..93e1cadd 100644
--- a/src/Listener/InitialCodeListener.php
+++ b/src/Listener/InitialCodeListener.php
@@ -34,12 +34,14 @@ public function __invoke(Event $event): void
     {
         $exercise = $event->getParameter('exercise');
 
-        if ($exercise instanceof ProvidesInitialCode) {
-            foreach ($exercise->getInitialCode()->getFiles() as $file) {
-                /** @var SolutionFile $file */
-                if (!file_exists($this->workingDirectory . '/' . $file->getRelativePath())) {
-                    copy($file->getAbsolutePath(), $this->workingDirectory . '/' . $file->getRelativePath());
-                }
+        if (!$exercise instanceof ProvidesInitialCode) {
+            return;
+        }
+
+        foreach ($exercise->getInitialCode()->getFiles() as $file) {
+            /** @var SolutionFile $file */
+            if (!file_exists($this->workingDirectory . '/' . $file->getRelativePath())) {
+                copy($file->getAbsolutePath(), $this->workingDirectory . '/' . $file->getRelativePath());
             }
         }
     }