Draft: Issue #3526657 Create new SwitcherManager service and deprecate ToolbarHandler methods getLinks, getCachetags

Closes #3526657

src/Service/SwitcherManager.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\environment_indicator\Service;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Routing\CurrentRouteMatch;
+use Drupal\Core\Url;
+
+/**
+ * Manages active environment switcher entities and builds UI-ready link data.
+ *
+ * This service centralizes logic related to the environment switcher list,
+ * including filtering active switchers and formatting their metadata as
+ * render-ready link arrays. It also provides cache tags to support proper
+ * cache invalidation when switcher configuration changes.
+ *
+ * Responsibilities:
+ * - Load and filter switchers based on status (and eventually permissions).
+ * - Build renderable links for UI components (e.g., page top, toolbar).
+ * - Provide cache tags related to switcher listings.
+ *
+ * Future enhancements may include:
+ * - Per-switcher access checks (once fixed in the module).
+ * - Domain/path/language-aware filtering.
+ * - Grouping, prioritization, or transformations.
+ *
+ * This service intentionally keeps responsibilities simple and centralized.
+ * If needed, future refactors may extract access filtering, link rendering,
+ * or entity loading into dedicated services or helpers.
+ */
+class SwitcherManager {
+
+  /**
+   * The entity type manager service.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected EntityTypeManagerInterface $entityTypeManager;
+
+  /**
+   * The current route match service.
+   *
+   * @var \Drupal\Core\Routing\CurrentRouteMatch
+   */
+  protected CurrentRouteMatch $routeMatch;
+
+  /**
+   * Constructs a new SwitcherManager instance.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entityTypeManager
+   *   The entity type manager service.
+   * @param \Drupal\Core\Routing\CurrentRouteMatch $routeMatch
+   *   The current route match service.
+   */
+  public function __construct(EntityTypeManagerInterface $entityTypeManager, CurrentRouteMatch $routeMatch) {
+    $this->entityTypeManager = $entityTypeManager;
+    $this->routeMatch = $routeMatch;
+  }
+
+  /**
+   * Builds an array of environment switcher links.
+   *
+   * @return array[]
+   *   A render array of link definitions for each active environment.
+   */
+  public function getLinks(): array {
+    /** @var \Drupal\environment_indicator\Entity\EnvironmentIndicator[] $entities */
+    $entities = $this->entityTypeManager->getStorage('environment_indicator')->loadMultiple();
+
+    $current_path = Url::fromRoute('<current>')->toString();
+
+    $links = [];
+    foreach ($entities as $entity) {
+      if (!$entity->status() || empty($entity->getUrl())) {
+        continue;
+      }
+
+      $links[] = [
+        'attributes' => [
+          'style' => sprintf('color: %s; background-color: %s;', $entity->getFgColor(), $entity->getBgColor()),
+          'title' => t('Opens the current page in the selected environment.'),
+        ],
+        'title' => t('Open on @label', ['@label' => $entity->label()]),
+        'url' => Url::fromUri($entity->getUrl() . $current_path),
+        'type' => 'link',
+        'weight' => $entity->getWeight(),
+      ];
+    }
+
+    uasort($links, ['Drupal\Component\Utility\SortArray', 'sortByWeightElement']);
+
+    return $links;
+  }
+
+  /**
+   * Returns cache tags related to the switcher list.
+   *
+   * @return string[]
+   *   An array of cache tags.
+   */
+  public function getCacheTags(): array {
+    return $this->entityTypeManager
+      ->getDefinition('environment_indicator')
+      ->getListCacheTags();
+  }
+
+}