Rename and re-organise custom modules

- Rename `opd_talks` to `opdavies_talks`
- Rename `custom` to `opdavies_blog`

web/modules/custom/opdavies_blog/src/EventSubscriber/PushBlogPostToSocialMedia.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\opdavies_blog\EventSubscriber;
+
+use Drupal\hook_event_dispatcher\Event\Entity\BaseEntityEvent;
+use Drupal\hook_event_dispatcher\HookEventDispatcherInterface;
+use Drupal\opdavies_blog\Entity\Node\Post;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+final class PushBlogPostToSocialMedia implements EventSubscriberInterface {
+
+  /**
+   * @inheritDoc
+   */
+  public static function getSubscribedEvents() {
+    return [
+      HookEventDispatcherInterface::ENTITY_PRE_SAVE => 'onEntityPreSave',
+    ];
+  }
+
+  public function onEntityPresave(BaseEntityEvent $event): void {
+    $entity = $event->getEntity();
+
+    if ($entity->getEntityTypeId() != 'node') {
+      return;
+    }
+
+    /** @var Post $entity */
+    if ($entity->bundle() != 'post') {
+      return;
+    }
+
+    if (!$entity->isPublished()) {
+      return;
+    }
+
+    // If this post has already been sent to social media, do not send it again.
+    if ($entity->hasBeenSentToSocialMedia()) {
+      return;
+    }
+
+    if ($entity->isExternalPost()) {
+      return;
+    }
+
+    $url = \Drupal::configFactory()->get('opdavies_talks.config')
+      ->get('zapier_post_tweet_url');
+
+    \Drupal::httpClient()->post($url, [
+      'form_params' => [
+        'message' => $entity->toTweet(),
+      ],
+    ]);
+
+    $entity->set('field_sent_to_social_media', TRUE);
+  }
+
+}