From 742f659b10e814179d8869624a37839800996af5 Mon Sep 17 00:00:00 2001
From: Jon Robson <jdlrobson@gmail.com>
Date: Thu, 1 Sep 2022 09:58:56 -0700
Subject: [PATCH] FeatureManagement: All features have an associated class on
 the body tag

This is a common need for features, and having these use a standardized
class name will make using them a lot easier.

Change-Id: I0e16c26878e7d4399d2bf57f236523d214951a27
---
 includes/FeatureManagement/FeatureManager.php | 15 ++++++++++++++
 includes/Hooks.php                            |  5 ++---
 .../components/LanguageButton.less            |  2 +-
 .../FeatureManagement/FeatureManagerTest.php  | 20 +++++++++++++++++++
 4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/includes/FeatureManagement/FeatureManager.php b/includes/FeatureManagement/FeatureManager.php
index cbcb508c..497fbeef 100644
--- a/includes/FeatureManagement/FeatureManager.php
+++ b/includes/FeatureManagement/FeatureManager.php
@@ -126,6 +126,21 @@ final class FeatureManager {
 		$this->features[$feature] = $requirements;
 	}
 
+	/**
+	 * Return a list of classes that should be added to the body tag
+	 *
+	 * @return array
+	 */
+	public function getFeatureBodyClass() {
+		$featureManager = $this;
+		return array_map( static function ( $featureName ) use ( $featureManager ) {
+			// switch to lower case and switch from camel case to hyphens
+			$featureClass = ltrim( strtolower( preg_replace( '/[A-Z]([A-Z](?![a-z]))*/', '-$0', $featureName ) ), '-' );
+			$prefix = 'vector-feature-' . $featureClass . '-';
+			return $featureManager->isFeatureEnabled( $featureName ) ? $prefix . 'enabled' : $prefix . 'disabled';
+		}, array_keys( $this->features ) );
+	}
+
 	/**
 	 * Gets whether the feature's requirements are met.
 	 *
diff --git a/includes/Hooks.php b/includes/Hooks.php
index 32b51853..1e3db76c 100644
--- a/includes/Hooks.php
+++ b/includes/Hooks.php
@@ -650,9 +650,8 @@ class Hooks implements
 		}
 
 		$featureManager = VectorServices::getFeatureManager();
-		if ( $featureManager->isFeatureEnabled( Constants::FEATURE_LANGUAGE_IN_MAIN_PAGE_HEADER ) ) {
-			$bodyAttrs['class'] .= ' vector-language-in-header-enabled';
-		}
+		$bodyAttrs['class'] .= ' ' . implode( ' ', $featureManager->getFeatureBodyClass() );
+		$bodyAttrs['class'] = trim( $bodyAttrs['class'] );
 	}
 
 	/**
diff --git a/resources/skins.vector.styles/components/LanguageButton.less b/resources/skins.vector.styles/components/LanguageButton.less
index cd03a03f..c2234c32 100644
--- a/resources/skins.vector.styles/components/LanguageButton.less
+++ b/resources/skins.vector.styles/components/LanguageButton.less
@@ -2,7 +2,7 @@
 @import '../../common/variables.less';
 @import 'mediawiki.mixins.less';
 
-// Note vector-language-in-header-enabled class is not used here as that class
+// Note vector-feature-language-in-header-enabled class is not used here as that class
 // only applies to main page.
 // This must be limited to mw-body-header as the mw-portlet-lang class is shared with
 // the language portlet that can display in the sidebar.
diff --git a/tests/phpunit/unit/FeatureManagement/FeatureManagerTest.php b/tests/phpunit/unit/FeatureManagement/FeatureManagerTest.php
index 73de2fe2..5f7309ee 100644
--- a/tests/phpunit/unit/FeatureManagement/FeatureManagerTest.php
+++ b/tests/phpunit/unit/FeatureManagement/FeatureManagerTest.php
@@ -61,6 +61,26 @@ class FeatureManagerTest extends \MediaWikiUnitTestCase {
 		];
 	}
 
+	/**
+	 * @covers ::getFeatureBodyClass
+	 */
+	public function testGetFeatureBodyClass() {
+		$featureManager = new FeatureManager();
+		$featureManager->registerSimpleRequirement( 'requirement', true );
+		$featureManager->registerSimpleRequirement( 'disabled', false );
+		$featureManager->registerFeature( 'sticky-header', [ 'requirement' ] );
+		$featureManager->registerFeature( 'TableOfContents', [ 'requirement' ] );
+		$featureManager->registerFeature( 'Test', [ 'disabled' ] );
+		$this->assertEquals(
+			[
+				'vector-feature-sticky-header-enabled',
+				'vector-feature-table-of-contents-enabled',
+				'vector-feature-test-disabled'
+			],
+			$featureManager->getFeatureBodyClass()
+		);
+	}
+
 	/**
 	 * @dataProvider provideInvalidFeatureConfig
 	 * @covers ::registerFeature