imp: add operation, action link

src/Form/EventTicketMaticForm.php

+<?php
+
+namespace Drupal\druplan_ticketmatic\Form;
+
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+use Drupal\druplan_ticketmatic\DruplanTicketmatic;
+use Drupal\resource_planning\Entity\Event;
+
+/**
+ * Provides a Druplan TicketMatic form.
+ */
+class EventTicketMaticForm extends FormBase {
+
+  /**
+   * The TicketMatic API.
+   *
+   * @var \Drupal\druplan_ticketmatic\DruplanTicketmatic
+   */
+  protected $ticketmatic;
+
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * The event.
+   *
+   * @var \Drupal\resource_planning\Entity\Event
+   */
+  protected $event;
+
+  /**
+   * Constructs a Drupal\druplan_ticketmatic\Form\EventTicketMaticForm object.
+   */
+  public function __construct(DruplanTicketmatic $ticketmatic, EntityTypeManagerInterface $entity_type_manager) {
+    $this->ticketmatic = $ticketmatic;
+    $this->entityTypeManager = $entity_type_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('druplan_ticketmatic.default'),
+      $container->get('entity_type.manager'),
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'druplan_ticketmatic_event_ticket_matic';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state, Event $rp_event = NULL) {
+    if ($rp_event) {
+      $this->event = $rp_event;
+    }
+
+    $form['intro'] = [
+      '#markup' => $this->t('Are you sure you wish to create a TicketMatic event?'),
+    ];
+
+    $view_builder = $this->entityTypeManager->getViewBuilder('rp_event');
+    $form['details'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Event Details'),
+      '#open' => TRUE,
+      'details' => $view_builder->build(
+        $view_builder->view($this->event)
+      ),
+    ];
+
+    $form['actions'] = [
+      '#type' => 'actions',
+    ];
+    $form['actions']['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Send'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {
+    if ($this->event->get('ticketmatic_id')->value) {
+      $form_state->setErrorByName(
+        'actions',
+        $this->t('This event already has a ticketmatic ID')
+      );
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $this->ticketmatic->createEvent(
+      $this->event);
+    $this->messenger()->addStatus($this->t('The Event has been created.'));
+  }
+
+}