Add multilanguage support

src/Http/Router.php

@@ -4,6 +4,8 @@
 
 use KittyShare\Model\Dependencies;
 use KittyShare\Manager\ConfigManager;
+use KittyShare\Manager\TranslationManager;
+use KittyShare\Translations\Language;
 
 /**
  * The router is responsible for dispatching requests to the correct handler
@@ -95,6 +97,7 @@ public function dispatch(Method $method, string $path): Response
             parameters: [
                 'path' => $path,
                 'baseUrl' => ConfigManager::get()->baseUrl,
+                'translationManager' => new TranslationManager(Language::EN), // TODO: Do not hardcode
             ],
             statusCode: 404,
         );

src/Manager/TranslationManager.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace KittyShare\Manager;
+
+use KittyShare\Translations\Language;
+use KittyShare\Translations\TranslationKeys;
+use OutOfBoundsException;
+
+/**
+ * Manages the translation values the application uses
+ */
+final class TranslationManager
+{
+    /**
+     * @var array<string, pure-callable(string...): string|string> The key-value store for the translations
+     */
+    private readonly array $translations;
+
+    public function __construct(Language $language)
+    {
+        /** @var array<string, pure-callable(string...): string|string> $translations */
+        $translations = require __DIR__ . '/../Translations/' . $language->value . '.php';
+
+        $this->translations = $translations;
+    }
+
+    public function get(TranslationKeys $key, string ...$values): string
+    {
+        // If the key does not exist, something went wrong... badly.
+        if (!array_key_exists($key->value, $this->translations)) {
+            throw new OutOfBoundsException(
+                sprintf('Translation key "%s" does not exist.', $key->value),
+            );
+        }
+
+        $translation = $this->translations[$key->value];
+
+        if (is_string($translation)) {
+            return $translation;
+        }
+
+        return $translation(...$values);
+    }
+}

src/Template/error/404.php

@@ -1,18 +1,23 @@
 <?php
-/** @var string $path */
+use KittyShare\Manager\TranslationManager;
+use KittyShare\Translations\TranslationKeys;
+/**
+ * @var string $path
+ * @var TranslationManager $translationManager
+ */
 ?>
 <?php
 require_once __DIR__ . '/../partials/base.php';
 
 $GLOBALS['__kittyshare_base'] = $baseUrl ?? '';
 
-renderHeader("404 Page not found");
+renderHeader($translationManager->get(TranslationKeys::PAGE_404_TITLE));
 ?>
 <main>
-    <h1 class="title">404 Page not found</h1>
-    <p>Hey! It seems like the site that you've tried to access does not exist.</p>
+    <h1 class="title"><?= $translationManager->get(TranslationKeys::PAGE_404_TITLE) ?></h1>
+    <p><?= $translationManager->get(TranslationKeys::PAGE_404_SUBTITLE) ?></p>
 
-    <p class="margin-top-6">Your requested path was &quot;<?= htmlspecialchars($path) ?>&quot;.</p>
+    <p class="margin-top-6"><?= e($translationManager->get(TranslationKeys::PAGE_404_PATHDESC, $path)) ?></p>
 </main>
 <?php
 renderFooter();

src/Translations/Language.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace KittyShare\Translations;
+
+enum Language: string
+{
+    case EN = 'en';
+}

src/Translations/TranslationKeys.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace KittyShare\Translations;
+
+enum TranslationKeys: string
+{
+    case KITTYSHARE_LOGO   = 'kittyshare.logo';
+    case PAGE_404_TITLE    = 'page.404.title';
+    case PAGE_404_SUBTITLE = 'page.404.subtitle';
+    case PAGE_404_PATHDESC = 'page.404.path';
+}

src/Translations/en.php

@@ -0,0 +1,10 @@
+<?php
+
+use KittyShare\Translations\TranslationKeys;
+
+return [
+    TranslationKeys::KITTYSHARE_LOGO->value   => 'KittyShare Logo',
+    TranslationKeys::PAGE_404_TITLE->value    => '404 Page not found',
+    TranslationKeys::PAGE_404_SUBTITLE->value => 'Hey! It seems like the site that you\'ve tried to access does not exist.',
+    TranslationKeys::PAGE_404_PATHDESC->value => fn(string $path) => "Your requested path was \"$path\".",
+];

tests/Http/TemplateResponseTest.php

@@ -2,6 +2,8 @@
 
 use KittyShare\Http\Response;
 use KittyShare\Http\TemplateResponse;
+use KittyShare\Manager\TranslationManager;
+use KittyShare\Translations\Language;
 use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 
@@ -51,7 +53,7 @@ public function rendersTemplateWithStatusCode(): void
     {
         $response = new TemplateResponse(
             'error/404',
-            ['path' => '/missing', 'baseUrl' => ''],
+            ['path' => '/missing', 'baseUrl' => '', 'translationManager' => new TranslationManager(Language::EN)],
             404,
         );
 
@@ -72,7 +74,7 @@ public function escapesTemplateParameters(): void
     {
         $response = new TemplateResponse(
             'error/404',
-            ['path' => '/a<b>&"c"', 'baseUrl' => ''],
+            ['path' => '/a<b>&"c"', 'baseUrl' => '', 'translationManager' => new TranslationManager(Language::EN)],
             404,
         );