Decouple label building from Twig extension (#138)

It can be reused from PHP

README.md

@@ -148,6 +148,50 @@ final class MyEnum extends AbstractEnum
 }
 ```
 
+### Get label from a service
+
+If you want to get the constant label behind an enum value, you can instantiate 
+the `GetLabel` class and invoke it.
+
+```php
+use Greg0ire\Enum\Bridge\Symfony\Translator\GetLabel;
+
+$label = new GetLabel();
+$label($value, 'Your\Enum\Class');
+```
+
+To enable translation, require the `symfony/translation` component
+and pass a `Symfony\Contracts\Translation\TranslationInterface` instance on the 
+`GetLabel` constructor
+
+```php
+use Greg0ire\Enum\Bridge\Symfony\Translator\GetLabel;
+use Symfony\Contracts\Translation\TranslationInterface;
+
+$label = new GetLabel($translator);
+$label($value, 'Your\Enum\Class');
+```
+
+If you're using Symfony, tag the service and simply inject it.
+If translations are enabled, the `TranslatorInterface` will be automatically injected.
+
+```yaml
+services:
+    # ...
+    Greg0ire\Enum\Bridge\Symfony\Translator\Label: "@greg0ire_enum.symfony.translator.label"
+```
+
+```php
+public function index(GetLabel $label)
+{
+    $label($value, 'Your\Enum\Class');
+    $label($value, 'Your\Enum\Class', 'another_domain'); // Change the translation domain
+    $label($value, 'Your\Enum\Class', false); // Disable translation. In this case the class prefix wont be added
+    $label($value, 'Your\Enum\Class', false, true); // Disable translation but keep class prefix
+    $label($value, 'Your\Enum\Class', false, true, '.'); // Disable translation but keep class prefix with a custom separator
+}
+```
+
 ### Integration with other libraries
 
 `greg0ire/enum` integrates with other libraries. The list is available in the
@@ -230,8 +274,11 @@ You have to require the `twig/twig` package to get it working.
 
 The `enum_label` filter will try to return the constant label corresponding to the given value.
 
+This filter relies on the `Greg0ire\Enum\Bridge\Symfony\Translator\GetLabel` service.
+
 It will try to translate it if possible. To enable translation, require the `symfony/translation` component
-and pass a `Symfony\Contracts\Translation\TranslationInterface` instance on the `EnumExtension` constructor.
+and pass a `Symfony\Contracts\Translation\TranslationInterface` instance on the `GetLabel` constructor. 
+`GetLabel` instance will be injected on the `EnumExtension` constructor.
 
 If translation is not available, you will have the default label with class prefixing.
 

src/Bridge/Symfony/DependencyInjection/Compiler/TranslatorCompilerPass.php

@@ -18,7 +18,7 @@ final class TranslatorCompilerPass implements CompilerPassInterface
     public function process(ContainerBuilder $container): void
     {
         if (class_exists(AbstractExtension::class) && $container->hasDefinition('translator.default')) {
-            $container->getDefinition('greg0ire_enum.twig.extension.enum')
+            $container->getDefinition('greg0ire_enum.symfony.translator.label')
                 ->addArgument(new Reference('translator.default'));
         }
     }

src/Bridge/Symfony/DependencyInjection/Greg0ireEnumExtension.php

@@ -23,5 +23,7 @@ public function load(array $configs, ContainerBuilder $container): void
         if (class_exists(AbstractExtension::class)) {
             $loader->load('twig.xml');
         }
+
+        $loader->load('services.xml');
     }
 }

src/Bridge/Symfony/Resources/config/services.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<container xmlns="http://symfony.com/schema/dic/services"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+    <services>
+        <defaults public="false" />
+
+        <service id="greg0ire_enum.symfony.translator.label" class="Greg0ire\Enum\Bridge\Symfony\Translator\Label" public="true">
+            <argument type="service" id="translator.default" />
+        </service>
+
+    </services>
+</container>

src/Bridge/Symfony/Translator/GetLabel.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace Greg0ire\Enum\Bridge\Symfony\Translator;
+
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+final class GetLabel
+{
+    /**
+     * @var TranslatorInterface
+     */
+    private $translator;
+
+    public function __construct(TranslatorInterface $translator = null)
+    {
+        $this->translator = $translator;
+    }
+
+    /**
+     * Displays the label corresponding to a specific value of an enumeration.
+     *
+     * @param mixed       $value              Must exists in the enumeration class specified with $class
+     * @param string      $class              The enum class name
+     * @param string|bool $translationDomain  the translation domain to use if the translator if available.
+     *                                        string: Use the specified one
+     *                                        null: Use the default one
+     *                                        false: Do not use the translator
+     * @param bool        $classPrefixed      Prefix the label with the enum class. Defaults to true if the translator
+     *                                        is available and enabled, false otherwise.
+     * @param string      $namespaceSeparator namespace separator to use with the class prefix.
+     *                                        This takes effect only if $classPrefixed is true
+     */
+    public function __invoke(
+        $value,
+        string $class,
+        $translationDomain = null,
+        ?bool $classPrefixed = null,
+        ?string $namespaceSeparator = null
+    ): string {
+        // Determine if the translator can be used or not.
+        $useTranslation = $this->translator instanceof TranslatorInterface
+            && (is_null($translationDomain) || is_string($translationDomain));
+
+        // If not defined, guess the default behavior.
+        if (is_null($classPrefixed)) {
+            $classPrefixed = $useTranslation;
+        }
+
+        $label = array_search(
+            $value,
+            call_user_func([$class, 'getConstants'], 'strtolower', $classPrefixed, $namespaceSeparator)
+        );
+
+        if ($useTranslation) {
+            $translatedLabel = $this->translator->trans($label, [], $translationDomain);
+
+            return $translatedLabel ?: $label;
+        }
+
+        return $label;
+    }
+}

src/Bridge/Twig/Extension/EnumExtension.php

@@ -3,6 +3,7 @@
 namespace Greg0ire\Enum\Bridge\Twig\Extension;
 
 use Greg0ire\Enum\AbstractEnum;
+use Greg0ire\Enum\Bridge\Symfony\Translator\GetLabel;
 use Symfony\Contracts\Translation\TranslatorInterface;
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFilter;
@@ -14,16 +15,24 @@
 final class EnumExtension extends AbstractExtension
 {
     /**
-     * @var TranslatorInterface
+     * @var GetLabel
      */
-    private $translator;
+    private $label;
 
-    /**
-     * @param TranslatorInterface $translator
-     */
-    public function __construct(TranslatorInterface $translator = null)
+    public function __construct($label)
     {
-        $this->translator = $translator;
+        if ($label instanceof TranslatorInterface) {
+            @trigger_error(sprintf(
+                'Providing a %s instance to %s is deprecated and will not be supported in 5.0. Please provide a %s instance instead.',
+                TranslatorInterface::class,
+                __METHOD__,
+                GetLabel::class
+            ), E_USER_DEPRECATED);
+            $this->label = new GetLabel($label);
+
+            return;
+        }
+        $this->label = $label;
     }
 
     /**
@@ -67,27 +76,7 @@ public function label(
         ?bool $classPrefixed = null,
         ?string $namespaceSeparator = null
     ): string {
-        // Determine if the translator can be used or not.
-        $useTranslation = $this->translator instanceof TranslatorInterface
-            && (is_null($translationDomain) || is_string($translationDomain));
-
-        // If not defined, guess the default behavior.
-        if (is_null($classPrefixed)) {
-            $classPrefixed = $useTranslation;
-        }
-
-        $label = array_search(
-            $value,
-            call_user_func([$class, 'getConstants'], 'strtolower', $classPrefixed, $namespaceSeparator)
-        );
-
-        if ($useTranslation) {
-            $translatedLabel = $this->translator->trans($label, [], $translationDomain);
-
-            return $translatedLabel ?: $label;
-        }
-
-        return $label;
+        return ($this->label)($value, $class, $translationDomain, $classPrefixed, $namespaceSeparator);
     }
 
     /**

tests/Bridge/Symfony/DependencyInjection/Greg0ireEnumExtensionTest.php

@@ -60,7 +60,7 @@ public function testLoadWithoutATranslator()
         );
     }
 
-    public function testTwigExtensionHasTheTranslator()
+    public function testLabelServiceHasTheTranslator()
     {
         $this->registerService('translator.logging.inner', \stdClass::class);
         $this->registerService('logger', \stdClass::class);
@@ -74,7 +74,7 @@ public function testTwigExtensionHasTheTranslator()
         $compilerPass->process($this->container);
 
         $this->assertContainerBuilderHasServiceDefinitionWithArgument(
-            'greg0ire_enum.twig.extension.enum',
+            'greg0ire_enum.symfony.translator.label',
             0,
             new Reference('translator.default')
         );

tests/Bridge/Twig/Extension/EnumExtensionTest.php

@@ -2,6 +2,7 @@
 
 namespace Greg0ire\Enum\Tests\Bridge\Twig\Extension;
 
+use Greg0ire\Enum\Bridge\Symfony\Translator\GetLabel;
 use Greg0ire\Enum\Bridge\Twig\Extension\EnumExtension;
 use Greg0ire\Enum\Tests\Fixtures\FooEnum;
 use Greg0ire\Enum\Tests\Fixtures\FooInterface;
@@ -32,7 +33,7 @@ final class EnumExtensionTest extends TestCase
     protected function setUp(): void
     {
         $this->translator = $this->createMock(TranslatorInterface::class);
-        $this->extension = new EnumExtension($this->translator);
+        $this->extension = new EnumExtension(new GetLabel($this->translator));
     }
 
     public function testEnvironment()