<?php

namespace Drupal\form_test\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Symfony\Component\HttpFoundation\JsonResponse;

/**
 * Tests checkboxes zero.
 *
 * @internal
 */
class FormTestCheckboxesZeroForm extends FormBase {

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

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, $json = TRUE) {
    $form_state->set('json', $json);
    $form['checkbox_off'] = [
      '#title' => t('Checkbox off'),
      '#type' => 'checkboxes',
      '#options' => ['foo', 'bar', 'baz'],
    ];
    $form['checkbox_zero_default'] = [
      '#title' => t('Zero default'),
      '#type' => 'checkboxes',
      '#options' => ['foo', 'bar', 'baz'],
      '#default_value' => [0],
    ];
    $form['checkbox_string_zero_default'] = [
      '#title' => t('Zero default (string)'),
      '#type' => 'checkboxes',
      '#options' => ['foo', 'bar', 'baz'],
      '#default_value' => ['0'],
    ];
    $form['submit'] = [
      '#type' => 'submit',
      '#value' => 'Save',
    ];
    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    if ($form_state->get('json')) {
      $form_state->setResponse(new JsonResponse($form_state->getValues()));
    }
    else {
      $form_state->disableRedirect();
    }
  }

}