<?php

declare(strict_types=1);

namespace Drupal\Tests\ckeditor5\FunctionalJavascript;

use Drupal\ckeditor5\Plugin\CKEditor5Plugin\Style;
use Drupal\ckeditor5\Plugin\Editor\CKEditor5;
use Drupal\editor\Entity\Editor;
use Drupal\filter\Entity\FilterFormat;
use Drupal\Tests\ckeditor5\Traits\CKEditor5TestTrait;
// cspell:ignore sourceediting
use PHPUnit\Framework\Attributes\CoversClass;
use PHPUnit\Framework\Attributes\Group;
use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
use Symfony\Component\Validator\ConstraintViolationInterface;

/**
 * Tests Drupal\ckeditor5\Plugin\CKEditor5Plugin\Style.
 *
 * @internal
 */
#[CoversClass(Style::class)]
#[Group('ckeditor5')]
#[RunTestsInSeparateProcesses]
class StyleTest extends CKEditor5TestBase {

  use CKEditor5TestTrait;

  /**
   * Tests style settings form.
   *
   * @legacy-covers \Drupal\ckeditor5\Plugin\CKEditor5Plugin\Style::buildConfigurationForm
   */
  public function testStyleSettingsForm(): void {
    $this->drupalLogin($this->drupalCreateUser(['administer filters']));

    $page = $this->getSession()->getPage();
    $assert_session = $this->assertSession();

    $this->createNewTextFormat($page, $assert_session);

    // The Style plugin settings form should not be present.
    $assert_session->elementNotExists('css', '[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style"]');

    $this->assertNotEmpty($assert_session->waitForElement('css', '.ckeditor5-toolbar-item-style'));
    $this->triggerKeyUp('.ckeditor5-toolbar-item-style', 'ArrowDown');
    $assert_session->assertWaitOnAjaxRequest();

    // No validation error upon enabling the Style plugin.
    $this->assertNoRealtimeValidationErrors();
    $assert_session->pageTextContains('No styles configured');

    // Still no validation error when configuring other functionality first.
    $this->triggerKeyUp('.ckeditor5-toolbar-item-undo', 'ArrowDown');
    $assert_session->assertWaitOnAjaxRequest();
    $this->assertNoRealtimeValidationErrors();

    // The Style plugin settings form should now be present and should have no
    // styles configured.
    $page->clickLink('Style');
    $this->assertNotNull($assert_session->waitForElementVisible('css', '[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"]'));

    $javascript = <<<JS
      const allowedTags = document.querySelector('[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"]');
      allowedTags.value = 'p.foo.bar  | Foobar paragraph';
      allowedTags.dispatchEvent(new Event('input'));
JS;
    $this->getSession()->executeScript($javascript);

    // Immediately save the configuration. Intentionally do nothing that would
    // trigger an AJAX rebuild.
    $page->pressButton('Save configuration');
    $assert_session->pageTextContains('Added text format');

    // Verify that the configuration was saved.
    $this->drupalGet('admin/config/content/formats/manage/ckeditor5');
    $page->clickLink('Style');
    $this->assertNotNull($styles_textarea = $assert_session->waitForElementVisible('css', '[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"]'));

    $this->assertSame("p.foo.bar|Foobar paragraph\n", $styles_textarea->getValue());
    $assert_session->pageTextContains('One style configured');
    $allowed_html_field = $assert_session->fieldExists('filters[filter_html][settings][allowed_html]');
    $this->assertStringContainsString('<p class="foo bar">', $allowed_html_field->getValue());

    // Attempt to use an unsupported HTML5 tag.
    $javascript = <<<JS
      const allowedTags = document.querySelector('[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"]');
      allowedTags.value = 's.redacted|Redacted';
      allowedTags.dispatchEvent(new Event('change'));
JS;
    $this->getSession()->executeScript($javascript);

    // The CKEditor 5 module should refuse to specify styles on tags that cannot
    // (yet) be created.
    // @see \Drupal\ckeditor5\Plugin\Validation\Constraint\FundamentalCompatibilityConstraintValidator::checkAllHtmlTagsAreCreatable()
    $assert_session->waitForElement('css', '[role=alert][data-drupal-message-type="error"]:contains("The Style plugin needs another plugin to create <s>, for it to be able to create the following attributes: <s class="redacted">. Enable a plugin that supports creating this tag. If none exists, you can configure the Source Editing plugin to support it.")');
    // The entire vertical tab for "Style" settings should be marked up as the
    // cause of the error, which means the "Styles" text area in there is marked
    // too.
    $assert_session->elementExists('css', '.vertical-tabs__pane[data-ckeditor5-plugin-id="ckeditor5_style"][aria-invalid="true"]');
    $assert_session->elementExists('css', '.vertical-tabs__pane[data-ckeditor5-plugin-id="ckeditor5_style"] textarea[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"][aria-invalid="true"]');

    // Attempt to save anyway: the warning should become an error.
    $page->pressButton('Save configuration');
    $assert_session->pageTextNotContains('Added text format');
    $assert_session->elementExists('css', '[aria-label="Error message"]:contains("The Style plugin needs another plugin to create <s>, for it to be able to create the following attributes: <s class="redacted">. Enable a plugin that supports creating this tag. If none exists, you can configure the Source Editing plugin to support it.")');

    // Now, attempt to use a supported non-HTML5 tag.
    // @see \Drupal\ckeditor5\Plugin\Validation\Constraint\StyleSensibleElementConstraintValidator
    $javascript = <<<JS
      const allowedTags = document.querySelector('[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"]');
      allowedTags.value = 'drupal-media.sensational|Sensational media';
      allowedTags.dispatchEvent(new Event('change'));
JS;
    $this->getSession()->executeScript($javascript);

    // The CKEditor 5 module should refuse to allow styles on non-HTML5 tags.
    $assert_session->waitForElement('css', '[role=alert][data-drupal-message-type="error"]:contains("A style can only be specified for an HTML 5 tag. <drupal-media> is not an HTML5 tag.")');
    // The vertical tab for "Style" settings should not be marked up as the
    // cause of the error, but only the "Styles" text area in the vertical tab.
    $assert_session->elementNotExists('css', '.vertical-tabs__pane[data-ckeditor5-plugin-id="ckeditor5_style"][aria-invalid="true"]');
    $assert_session->elementExists('css', '.vertical-tabs__pane[data-ckeditor5-plugin-id="ckeditor5_style"] textarea[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"][aria-invalid="true"]');

    // Test configuration overlaps across plugins.
    $this->drupalGet('admin/config/content/formats/manage/ckeditor5');
    $this->assertNotEmpty($assert_session->elementExists('css', '.ckeditor5-toolbar-item-sourceEditing'));
    $this->triggerKeyUp('.ckeditor5-toolbar-item-sourceEditing', 'ArrowDown');
    $assert_session->assertWaitOnAjaxRequest();
    // The Source Editing plugin settings form should now be present and should
    // have no allowed tags configured.
    $page->clickLink('Source editing');
    $this->assertNotNull($assert_session->waitForElementVisible('css', '[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-sourceediting-allowed-tags"]'));

    // Make `<aside class>` creatable.
    $javascript = <<<JS
      const allowedTags = document.querySelector('[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-sourceediting-allowed-tags"]');
      allowedTags.value = '<aside class>';
      allowedTags.dispatchEvent(new Event('change'));
JS;
    $this->getSession()->executeScript($javascript);
    $assert_session->assertWaitOnAjaxRequest();

    // Create a style with `aside` and a class name.
    $javascript = <<<JS
      const allowedTags = document.querySelector('[data-drupal-selector="edit-editor-settings-plugins-ckeditor5-style-styles"]');
      allowedTags.value = 'aside.error|Aside';
      allowedTags.dispatchEvent(new Event('change'));
JS;
    $this->getSession()->executeScript($javascript);
    $assert_session->assertWaitOnAjaxRequest();

    // The CKEditor 5 module should refuse to create configuration overlaps
    // across plugins.
    // @see \Drupal\ckeditor5\Plugin\Validation\Constraint\StyleSensibleElementConstraintValidator::findStyleConflictingPluginLabel()
    $assert_session->waitForElement('css', '[role=alert][data-drupal-message-type="error"]:contains("A style must only specify classes not supported by other plugins.")');
  }

  /**
   * Tests Style functionality: setting a class, expected style choices.
   */
  public function testStyleFunctionality(): void {
    FilterFormat::create([
      'format' => 'test_format',
      'name' => 'Test format',
      'filters' => [
        'filter_html' => [
          'status' => TRUE,
          'settings' => [
            'allowed_html' => '<p class="highlighted interesting"> <br> <a href class="reliable"> <blockquote class="famous"> <h2 class="red-heading"> <ul class="items"> <ol class="steps"> <li> <table class="data-analysis"> <tr> <td rowspan colspan> <th rowspan colspan> <thead> <tbody> <tfoot> <caption class="caution"> <div class="deep-dive">',
          ],
        ],
      ],
    ])->save();
    Editor::create([
      'editor' => 'ckeditor5',
      'format' => 'test_format',
      'settings' => [
        'toolbar' => [
          'items' => [
            'heading',
            'link',
            'blockQuote',
            'style',
            'bulletedList',
            'numberedList',
            'insertTable',
            'sourceEditing',
          ],
        ],
        'plugins' => [
          'ckeditor5_heading' => [
            'enabled_headings' => [
              'heading2',
            ],
          ],
          'ckeditor5_list' => [
            'properties' => [
              'reversed' => FALSE,
              'startIndex' => FALSE,
              'styles' => FALSE,
            ],
            'multiBlock' => TRUE,
          ],
          'ckeditor5_sourceEditing' => [
            'allowed_tags' => [
              '<div>',
            ],
          ],
          'ckeditor5_style' => [
            'styles' => [
              [
                'label' => 'Highlighted & interesting',
                'element' => '<p class="highlighted interesting">',
              ],
              [
                'label' => 'Red heading',
                'element' => '<h2 class="red-heading">',
              ],
              [
                'label' => 'Reliable source',
                'element' => '<a class="reliable">',
              ],
              [
                'label' => 'Famous',
                'element' => '<blockquote class="famous">',
              ],
              [
                'label' => 'Items',
                'element' => '<ul class="items">',
              ],
              [
                'label' => 'Steps',
                'element' => '<ol class="steps">',
              ],
              [
                'label' => 'Data analysis',
                'element' => '<table class="data-analysis">',
              ],
              [
                'label' => 'Truly deep dive',
                'element' => '<div class="deep-dive">',
              ],
              [
                'label' => 'Caution caption',
                'element' => '<caption class="caution">',
              ],
            ],
          ],
        ],
      ],
      'image_upload' => [
        'status' => FALSE,
      ],
    ])->save();
    $this->assertSame([], array_map(
      function (ConstraintViolationInterface $v) {
        return (string) $v->getMessage();
      },
      iterator_to_array(CKEditor5::validatePair(
        Editor::load('test_format'),
        FilterFormat::load('test_format')
      ))
    ));

    // Create a sample entity to test CKEditor 5.
    $node = $this->createNode([
      'type' => 'page',
      'title' => 'A selection of the history of Drupal',
      'body' => [
        'value' => '<h2>Upgrades</h2><p class="history">Drupal has historically been difficult to upgrade from one major version to the next.</p><p class="highlighted interesting">This changed with Drupal 8.</p><blockquote class="famous"><p>Updating from Drupal 8\'s latest version to Drupal 9.0.0 should be as easy as updating between minor versions of Drupal 8.</p></blockquote><p> — <a href="https://dri.es/making-drupal-upgrades-easy-forever">Dries</a></p><div><ul><li>Update Drupal core using Composer</li><li>Update Drupal core manually</li><li>Update Drupal core using Drush</li></ul><ol><li>Back up your files and database</li><li>Put your site into maintenance mode</li><li>Update the code and apply changes</li><li>Deactivate maintenance mode</li></ol><table><caption>Drupal upgrades are now easy, with a few caveats.</caption><tbody><tr><td>First</td><td>Second</td></tr><tr><td>Data value 1</td><td>Data value 2</td></tr></tbody></table></div>',
        'format' => 'test_format',
      ],
    ]);
    $node->save();

    // Observe.
    $this->drupalLogin($this->drupalCreateUser([
      'use text format test_format',
      'bypass node access',
    ]));

    // Set a taller window size to ensure all possible style choices are in view
    // because otherwise Mink's getText() will return the empty string for those
    // out of view, despite the HTML showing that text.
    $this->getSession()->resizeWindow(1024, 1000);

    $this->drupalGet($node->toUrl('edit-form'));
    $this->waitForEditor();

    // Select the <h2>, assert that no style is active currently.
    $this->selectTextInsideElement('h2');
    $assert_session = $this->assertSession();
    $style_dropdown = $assert_session->elementExists('css', '.ck-style-dropdown');
    $this->assertSame('Styles', $style_dropdown->getText());

    // Click the dropdown, check the available styles.
    $style_dropdown->click();
    $buttons = $style_dropdown->findAll('css', '.ck-dropdown__panel button');
    $this->assertCount(9, $buttons);

    $this->assertSame('Highlighted & interesting', $buttons[0]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Red heading', $buttons[1]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Famous', $buttons[2]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Items', $buttons[3]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Steps', $buttons[4]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Data analysis', $buttons[5]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Truly deep dive', $buttons[6]->find('css', '.ck-button__label')->getText());
    $this->assertSame('Caution caption', $buttons[7]->find('css', '.ck-button__label')->getText());
    // CKEditor's Style plugin first shows all block styles.
    for ($i = 0; $i <= 7; $i++) {
      $style_group = $buttons[$i]->getParent()->getParent();
      $this->assertTrue($style_group->hasClass('ck-style-panel__style-group'));
      $this->assertSame('Block styles', $style_group->find('css', 'label')->getText());
    }
    // And then all text styles.
    for ($i = 8; $i <= 8; $i++) {
      $style_group = $buttons[$i]->getParent()->getParent();
      $this->assertTrue($style_group->hasClass('ck-style-panel__style-group'));
      $this->assertSame('Text styles', $style_group->find('css', 'label')->getText());
    }
    $this->assertSame('Reliable source', $buttons[8]->find('css', '.ck-button__label')->getText());

    $this->assertSame('true', $buttons[0]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[1]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[6]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));

    // Apply the "Red heading" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main h2:not(.red-heading)');
    $buttons[1]->click();
    $assert_session->elementExists('css', '.ck-editor__main h2.red-heading');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-on'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('Red heading', $style_dropdown->getText());

    // Select the first paragraph and observe changes in:
    // - styles dropdown label
    // - button states
    $this->selectTextInsideElement('p');
    $this->assertSame('Styles', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[6]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));
    // Close the dropdown.
    $style_dropdown->click();

    // Select the blockquote and observe changes in:
    // - styles dropdown label
    // - button states
    $this->selectTextInsideElement('blockquote');
    $this->assertSame('Famous', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-on'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    // TRICKY: the blockquote contains a paragraph.
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[2]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[6]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));
    // Close the dropdown.
    $style_dropdown->click();

    // Select the <ul> and check the available styles.
    $this->selectTextInsideElement('ul');
    $this->assertSame('Styles', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    // TRICKY: the contents of the list item can be converted to a paragraph.
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[3]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    // TRICKY: the <ul> is wrapped in a <div>, so the "Truly deep dive" <div>
    // style is available!
    $this->assertFalse($buttons[6]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));

    // Apply the "Items" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main ul:not(.items)');
    $buttons[3]->click();
    $assert_session->elementExists('css', '.ck-editor__main ul.items');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-on'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('Items', $style_dropdown->getText());

    // Select the <ol> and check the available styles.
    $this->selectTextInsideElement('ol');
    $this->assertSame('Styles', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    // TRICKY: the contents of the list item can be converted to a paragraph.
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[4]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    // TRICKY: the <ol> is wrapped in a <div>, so the "Truly deep dive" <div>
    // style is available!
    $this->assertFalse($buttons[6]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));

    // Apply the "Steps" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main ol:not(.steps)');
    $buttons[4]->click();
    $assert_session->elementExists('css', '.ck-editor__main ol.steps');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-on'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('Steps', $style_dropdown->getText());

    // Select the table and check the available styles.
    $this->selectTextInsideElement('table td');
    $this->assertSame('Styles', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    // TRICKY: the contents of the table cell can be converted to a paragraph.
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[5]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[6]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));

    // Apply the "Data analysis" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main table:not(.data-analysis)');
    $buttons[5]->click();
    $assert_session->elementExists('css', '.ck-editor__main table.data-analysis');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-on'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('Data analysis', $style_dropdown->getText());

    // Select the link, assert that no style is active currently.
    $this->selectTextInsideElement('a');
    $this->assertSame('Styles', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    // TRICKY: the link is inside a paragraph.
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[6]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[8]->hasAttribute('aria-disabled'));

    // Apply the "Reliable source" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main a:not(.reliable)');
    $buttons[8]->click();
    $assert_session->elementExists('css', '.ck-editor__main a.reliable');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-on'));
    $this->assertSame('Reliable source', $style_dropdown->getText());

    // Because we cannot select the <div> directly (it's not a visible element),
    // select the <ol> AGAIN and check the available styles — because we should
    // be able to change the containing <div>'s style through here. Note that we
    // already activated the "Steps" style previously.
    $this->selectTextInsideElement('ol');
    $this->assertSame('Steps', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-on'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    // TRICKY: the contents of the list item can be converted to a paragraph.
    $this->assertFalse($buttons[0]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[4]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[5]->getAttribute('aria-disabled'));
    // TRICKY: the <ol> is wrapped in a <div>, so the "Truly deep dive" <div>
    // style is available!
    $this->assertFalse($buttons[6]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[7]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));

    // Apply the "Truly deep dive" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main div:not(.deep-dive)');
    $buttons[6]->click();
    $assert_session->elementExists('css', '.ck-editor__main div.deep-dive');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-on'));
    $this->assertTrue($buttons[5]->hasClass('ck-off'));
    $this->assertTrue($buttons[6]->hasClass('ck-on'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('Multiple styles', $style_dropdown->getText());

    // Select the table caption, assert that no style is active currently.
    $this->selectTextInsideElement('figure.table > figcaption');
    $this->assertSame('Data analysis', $style_dropdown->getText());
    $style_dropdown->click();
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    // TRICKY: the caption is inside the table, so the "Data analysis" style is
    // also active.
    $this->assertTrue($buttons[5]->hasClass('ck-on'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-off'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('true', $buttons[0]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[1]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[2]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[3]->getAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[4]->getAttribute('aria-disabled'));
    // TRICKY: the caption is inside the table, so the "Data analysis" style is
    // also active.
    $this->assertFalse($buttons[5]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[6]->getAttribute('aria-disabled'));
    $this->assertFalse($buttons[7]->hasAttribute('aria-disabled'));
    $this->assertSame('true', $buttons[8]->getAttribute('aria-disabled'));

    // Apply the "Caution caption" style and verify it has the expected effect.
    $assert_session->elementExists('css', '.ck-editor__main figure.table > figcaption:not(.caution)');
    $buttons[7]->click();
    $assert_session->elementExists('css', '.ck-editor__main figure.table > figcaption.caution');
    $this->assertTrue($buttons[0]->hasClass('ck-off'));
    $this->assertTrue($buttons[1]->hasClass('ck-off'));
    $this->assertTrue($buttons[2]->hasClass('ck-off'));
    $this->assertTrue($buttons[3]->hasClass('ck-off'));
    $this->assertTrue($buttons[4]->hasClass('ck-off'));
    $this->assertTrue($buttons[5]->hasClass('ck-on'));
    $this->assertTrue($buttons[6]->hasClass('ck-off'));
    $this->assertTrue($buttons[7]->hasClass('ck-on'));
    $this->assertTrue($buttons[8]->hasClass('ck-off'));
    $this->assertSame('Multiple styles', $style_dropdown->getText());

    // The resulting markup should be identical to the starting markup, with
    // seven changes:
    // 1. the `red-heading` class has been added to the `<h2>`
    // 2. the `history` class has been removed from the `<p>`, because CKEditor
    //    5 has not been configured for this: if a Style had configured for it,
    //    it would have been retained.
    // 3. the `items` class has been added to the `<ul>`
    // 4. the `steps` class has been added to the `<ol>`
    // 5. the `data-analysis` class has been added to the `<table>`
    // 6. the `reliable` class has been added to the `<a>`
    // 7. The `deep-dive` class has been added to the `<div>`
    // 8. The `caution` class has been added to the `<caption>`
    $this->assertSame('<h2 class="red-heading">Upgrades</h2><p>Drupal has historically been difficult to upgrade from one major version to the next.</p><p class="highlighted interesting">This changed with Drupal 8.</p><blockquote class="famous"><p>Updating from Drupal 8\'s latest version to Drupal 9.0.0 should be as easy as updating between minor versions of Drupal 8.</p></blockquote><p>— <a class="reliable" href="https://dri.es/making-drupal-upgrades-easy-forever">Dries</a></p><div class="deep-dive"><ul class="items"><li>Update Drupal core using Composer</li><li>Update Drupal core manually</li><li>Update Drupal core using Drush</li></ul><ol class="steps"><li>Back up your files and database</li><li>Put your site into maintenance mode</li><li>Update the code and apply changes</li><li>Deactivate maintenance mode</li></ol><table class="table data-analysis"><caption class="caution">Drupal upgrades are now easy, with a few caveats.</caption><tbody><tr><td>First</td><td>Second</td></tr><tr><td>Data value 1</td><td>Data value 2</td></tr></tbody></table></div>', $this->getEditorDataAsHtmlString());
  }

}
