social_event_invite_flow-1.0.0-beta3/src/Form/InviteMessagesForm.php

<?php

namespace Drupal\social_event_invite_flow\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Provides a Social event invite flow form.
 */
class InviteMessagesForm extends FormBase {

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'social_event_invite_flow_invite_messages';
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {

    $form['message'] = [
      '#type' => 'textarea',
      '#title' => $this->t('Message'),
      '#required' => TRUE,
    ];
    
    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function validateForm(array &$form, FormStateInterface $form_state) {
    if (mb_strlen($form_state->getValue('message')) < 10) {
      $form_state->setErrorByName('message', $this->t('Message should be at least 10 characters.'));
    }
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
  }

}