Use OOP hooks

Closes #3497621

src/Hook/RedirectMetricsHooks.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\redirect_metrics\Hook;
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Hook\Attribute\Hook;
+use Drupal\redirect\Entity\Redirect;
+use Drupal\redirect_metrics\RedirectMetricsFieldDefinitions;
+
+/**
+ * Hook implementations for the redirect_metrics module.
+ */
+class RedirectMetricsHooks {
+
+  /**
+   * Implements hook_entity_base_field_info().
+   */
+  #[Hook('entity_base_field_info')]
+  public function entityBaseFieldInfo(EntityTypeInterface $entityType): array {
+    if ($entityType->id() !== 'redirect') {
+      return [];
+    }
+    return RedirectMetricsFieldDefinitions::getAll();
+  }
+
+  /**
+   * Implements hook_ENTITY_TYPE_presave().
+   */
+  #[Hook('redirect_presave')]
+  public function redirectPresave(Redirect $redirect): void {
+    // Initialise the default metrics when a new redirect is created.
+    if ($redirect->isNew()) {
+      // Set the access count if it's empty.
+      if ($redirect->access_count->isEmpty()) {
+        $redirect->access_count->value = 0;
+      }
+    }
+  }
+
+}