class MessageForm

class MessageForm extends ContentEntityForm {
    
    /**
     * The message being used by this form.
     *
     * @var \Drupal\contact\MessageInterface
     */
    protected $entity;
    
    /**
     * The flood control mechanism.
     *
     * @var \Drupal\Core\Flood\FloodInterface
     */
    protected $flood;
    
    /**
     * The language manager service.
     *
     * @var \Drupal\Core\Language\LanguageManagerInterface
     */
    protected $languageManager;
    
    /**
     * The contact mail handler service.
     *
     * @var \Drupal\contact\MailHandlerInterface
     */
    protected $mailHandler;
    
    /**
     * The date formatter service.
     *
     * @var \Drupal\Core\Datetime\DateFormatterInterface
     */
    protected $dateFormatter;
    
    /**
     * Constructs a MessageForm object.
     *
     * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
     *   The entity repository.
     * @param \Drupal\Core\Flood\FloodInterface $flood
     *   The flood control mechanism.
     * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
     *   The language manager service.
     * @param \Drupal\contact\MailHandlerInterface $mail_handler
     *   The contact mail handler service.
     * @param \Drupal\Core\Datetime\DateFormatterInterface $date_formatter
     *   The date service.
     * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
     *   The entity type bundle service.
     * @param \Drupal\Component\Datetime\TimeInterface $time
     *   The time service.
     */
    public function __construct(EntityRepositoryInterface $entity_repository, FloodInterface $flood, LanguageManagerInterface $language_manager, MailHandlerInterface $mail_handler, DateFormatterInterface $date_formatter, EntityTypeBundleInfoInterface $entity_type_bundle_info = NULL, TimeInterface $time = NULL) {
        parent::__construct($entity_repository, $entity_type_bundle_info, $time);
        $this->flood = $flood;
        $this->languageManager = $language_manager;
        $this->mailHandler = $mail_handler;
        $this->dateFormatter = $date_formatter;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity.repository'), $container->get('flood'), $container->get('language_manager'), $container->get('contact.mail_handler'), $container->get('date.formatter'), $container->get('entity_type.bundle.info'), $container->get('datetime.time'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function form(array $form, FormStateInterface $form_state) {
        $user = $this->currentUser();
        $message = $this->entity;
        $form = parent::form($form, $form_state, $message);
        $form['#attributes']['class'][] = 'contact-form';
        if (!empty($message->preview)) {
            $form['preview'] = [
                '#theme_wrappers' => [
                    'container__preview',
                ],
                '#attributes' => [
                    'class' => [
                        'preview',
                    ],
                ],
            ];
            $form['preview']['message'] = $this->entityTypeManager
                ->getViewBuilder('contact_message')
                ->view($message, 'full');
        }
        $form['name'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Your name'),
            '#maxlength' => 255,
            '#required' => TRUE,
        ];
        $form['mail'] = [
            '#type' => 'email',
            '#title' => $this->t('Your email address'),
            '#required' => TRUE,
        ];
        if ($user->isAnonymous()) {
            $form['#attached']['library'][] = 'core/drupal.form';
            $form['#attributes']['data-user-info-from-browser'] = TRUE;
        }
        else {
            $form['name']['#type'] = 'item';
            $form['name']['#value'] = $user->getDisplayName();
            $form['name']['#required'] = FALSE;
            $form['name']['#plain_text'] = $user->getDisplayName();
            $form['mail']['#type'] = 'item';
            $form['mail']['#value'] = $user->getEmail();
            $form['mail']['#required'] = FALSE;
            $form['mail']['#plain_text'] = $user->getEmail();
        }
        // The user contact form has a preset recipient.
        if ($message->isPersonal()) {
            $form['recipient'] = [
                '#type' => 'item',
                '#title' => $this->t('To'),
                '#value' => $message->getPersonalRecipient()
                    ->id(),
                'name' => [
                    '#theme' => 'username',
                    '#account' => $message->getPersonalRecipient(),
                ],
            ];
        }
        $form['copy'] = [
            '#type' => 'checkbox',
            '#title' => $this->t('Send yourself a copy'),
            // Do not allow anonymous users to send themselves a copy, because it can
            // be abused to spam people.
'#access' => $user->isAuthenticated(),
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function actions(array $form, FormStateInterface $form_state) {
        $elements = parent::actions($form, $form_state);
        $elements['submit']['#value'] = $this->t('Send message');
        $elements['preview'] = [
            '#type' => 'submit',
            '#value' => $this->t('Preview'),
            '#submit' => [
                '::submitForm',
                '::preview',
            ],
            '#access' => !empty($form_state->getStorage()['form_display']
                ->getComponent('preview')),
        ];
        return $elements;
    }
    
    /**
     * Form submission handler for the 'preview' action.
     */
    public function preview(array $form, FormStateInterface $form_state) {
        $message = $this->entity;
        $message->preview = TRUE;
        $form_state->setRebuild();
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        $message = parent::validateForm($form, $form_state);
        // Check if flood control has been activated for sending emails.
        if (!$this->currentUser()
            ->hasPermission('administer contact forms') && (!$message->isPersonal() || !$this->currentUser()
            ->hasPermission('administer users'))) {
            $limit = $this->config('contact.settings')
                ->get('flood.limit');
            $interval = $this->config('contact.settings')
                ->get('flood.interval');
            if (!$this->flood
                ->isAllowed('contact', $limit, $interval)) {
                $form_state->setErrorByName('', $this->t('You cannot send more than %limit messages in @interval. Try again later.', [
                    '%limit' => $limit,
                    '@interval' => $this->dateFormatter
                        ->formatInterval($interval),
                ]));
            }
        }
        return $message;
    }
    
    /**
     * {@inheritdoc}
     */
    public function save(array $form, FormStateInterface $form_state) {
        $message = $this->entity;
        $user = $this->currentUser();
        // Save the message. In core this is a no-op but should contrib wish to
        // implement message storage, this will make the task of swapping in a real
        // storage controller straight-forward.
        $message->save();
        $this->mailHandler
            ->sendMailMessages($message, $user);
        $contact_form = $message->getContactForm();
        $this->flood
            ->register('contact', $this->config('contact.settings')
            ->get('flood.interval'));
        if ($submission_message = $contact_form->getMessage()) {
            $this->messenger()
                ->addStatus($submission_message);
        }
        // To avoid false error messages caused by flood control, redirect away from
        // the contact form; either to the contacted user account or the front page.
        if ($message->isPersonal() && $user->hasPermission('access user profiles')) {
            $form_state->setRedirectUrl($message->getPersonalRecipient()
                ->toUrl());
        }
        else {
            $form_state->setRedirectUrl($contact_form->getRedirectUrl());
        }
    }

}