Added Involved Parties block for case page

src/Plugin/Block/InvolvedParties.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Drupal\zencrm\Plugin\Block;
+
+use Drupal\Core\Block\BlockBase;
+
+/**
+ * Provides a 'Involved Parties' block.
+ * Block contains links to the people involved in a case
+ *
+ * @Block(
+ *  id = "involved_parties",
+ *  admin_label = @Translation("Involved Parties"),
+ * )
+ */
+class InvolvedParties extends BlockBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build() {
+    $case_id = \Drupal::routeMatch()->getParameter('case_entity')->id();
+    $markup = "";    
+    
+    $case = $entity = \Drupal::entityTypeManager()->getStorage('case_entity')->load($case_id);
+    $hats_involved = $case->hats_involved->referencedEntities();
+    foreach($hats_involved as $hat) {
+      $person_id = $hat->person->first()->getValue()['target_id'];
+      $markup .= "<p><a href='/zencrm/person/$person_id?backto=case&backtoid=$case_id'>" . $hat->name->getString() . "</a></p>";
+    }
+    return [
+      '#cache' => [
+         'max-age' => 0,
+       ],
+      '#markup' => "<div class='zencrm_links'>$markup</div>"
+    ];
+
+  }
+
+}