<?php

namespace Drupal\FunctionalJavascriptTests\Ajax;

use Drupal\Component\Render\FormattableMarkup;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\field\Entity\FieldConfig;
use Drupal\field\Entity\FieldStorageConfig;
use Drupal\FunctionalJavascriptTests\WebDriverTestBase;

/**
 * Tests that AJAX-enabled forms work when multiple instances of the same form
 * are on a page.
 *
 * @group Ajax
 */
class MultiFormTest extends WebDriverTestBase {

  /**
   * {@inheritdoc}
   */
  public static $modules = ['node', 'form_test'];

  /**
   * {@inheritdoc}
   */
  protected function setUp() {
    parent::setUp();

    $this->drupalCreateContentType(['type' => 'page', 'name' => 'Page']);

    // Create a multi-valued field for 'page' nodes to use for Ajax testing.
    $field_name = 'field_ajax_test';
    FieldStorageConfig::create([
      'entity_type' => 'node',
      'field_name' => $field_name,
      'type' => 'text',
      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
    ])->save();
    FieldConfig::create([
      'field_name' => $field_name,
      'entity_type' => 'node',
      'bundle' => 'page',
    ])->save();
    entity_get_form_display('node', 'page', 'default')
      ->setComponent($field_name, ['type' => 'text_textfield'])
      ->save();

    // Log in a user who can create 'page' nodes.
    $this->drupalLogin($this->drupalCreateUser(['create page content']));
  }

  /**
   * Tests that pages with the 'node_page_form' included twice work correctly.
   */
  public function testMultiForm() {
    // HTML IDs for elements within the field are potentially modified with
    // each Ajax submission, but these variables are stable and help target the
    // desired elements.
    $field_name = 'field_ajax_test';

    $form_xpath = '//form[starts-with(@id, "node-page-form")]';
    $field_xpath = '//div[contains(@class, "field--name-field-ajax-test")]';
    $button_name = $field_name . '_add_more';
    $button_value = t('Add another item');
    $button_xpath_suffix = '//input[@name="' . $button_name . '"]';
    $field_items_xpath_suffix = '//input[@type="text"]';

    // Ensure the initial page contains both node forms and the correct number
    // of field items and "add more" button for the multi-valued field within
    // each form.
    $this->drupalGet('form-test/two-instances-of-same-form');

    // Wait for javascript on the page to prepare the form attributes.
    $this->assertSession()->assertWaitOnAjaxRequest();

    $session = $this->getSession();
    $page = $session->getPage();
    $fields = $page->findAll('xpath', $form_xpath . $field_xpath);
    $this->assertEqual(count($fields), 2);
    foreach ($fields as $field) {
      $this->assertCount(1, $field->findAll('xpath', '.' . $field_items_xpath_suffix), 'Found the correct number of field items on the initial page.');
      $this->assertFieldsByValue($field->find('xpath', '.' . $button_xpath_suffix), NULL, 'Found the "add more" button on the initial page.');
    }

    $this->assertNoDuplicateIds();

    // Submit the "add more" button of each form twice. After each corresponding
    // page update, ensure the same as above.

    for ($i = 0; $i < 2; $i++) {
      $forms = $page->find('xpath', $form_xpath);
      foreach ($forms as $offset => $form) {
        $button = $form->findButton($button_value);
        $this->assertNotNull($button, 'Add Another Item button exists');
        $button->press();

        // Wait for page update.
        $this->assertSession()->assertWaitOnAjaxRequest();

        // After AJAX request and response page will update.
        $page_updated = $session->getPage();
        $field = $page_updated->findAll('xpath', '.' . $field_xpath);
        $this->assertEqual(count($field[0]->find('xpath', '.' . $field_items_xpath_suffix)), $i + 2, 'Found the correct number of field items after an AJAX submission.');
        $this->assertFieldsByValue($field[0]->find('xpath', '.' . $button_xpath_suffix), NULL, 'Found the "add more" button after an AJAX submission.');
        $this->assertNoDuplicateIds();
      }
    }
  }

  /**
   * Asserts that each HTML ID is used for just a single element on the page.
   *
   * @param string $message
   *   (optional) A message to display with the assertion.
   */
  protected function assertNoDuplicateIds($message = '') {
    $args = ['@url' => $this->getUrl()];

    if (!$elements = $this->xpath('//*[@id]')) {
      $this->fail(new FormattableMarkup('The page @url contains no HTML IDs.', $args));
      return;
    }

    $message = $message ?: new FormattableMarkup('The page @url does not contain duplicate HTML IDs', $args);

    $seen_ids = [];
    foreach ($elements as $element) {
      $id = $element->getAttribute('id');
      if (isset($seen_ids[$id])) {
        $this->fail($message);
        return;
      }
      $seen_ids[$id] = TRUE;
    }
    $this->assertTrue(TRUE, $message);
  }

}
