Rename and re-organise custom modules

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

web/modules/custom/opdavies_blog/src/Entity/Node/Post.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\opdavies_blog\Entity\Node;
+
+use Drupal\discoverable_entity_bundle_classes\ContentEntityBundleInterface;
+use Drupal\node\Entity\Node;
+
+/**
+ * Defines an blog post node class.
+ *
+ * @ContentEntityBundleClass(
+ *   label = @Translation("Blog post"),
+ *   entity_type = "node",
+ *   bundle = "post"
+ * );
+ */
+class Post extends Node implements ContentEntityBundleInterface {
+
+  public function getExternalLink(): ?array {
+    return ($link = $this->get('field_external_link')->get(0))
+      ? $link->getValue()
+      : NULL;
+  }
+
+  public function hasBeenSentToSocialMedia(): bool {
+    return (bool) $this->get('field_sent_to_social_media')->getString();
+  }
+
+  public function hasTweet(): bool {
+    return (bool) $this->get('field_has_tweet')->getString();
+  }
+
+  public function isExternalPost(): bool {
+    return (bool) $this->getExternalLink();
+  }
+
+  public function toTweet(): string {
+    // TODO: Add tags.
+
+    $parts = [$this->label(), $this->url('canonical', ['absolute' => TRUE])];
+
+    return implode(PHP_EOL . PHP_EOL, $parts);
+  }
+
+}