trait CKEditor5TestTrait

trait CKEditor5TestTrait {
    
    /**
     * Gets CKEditor 5 instance data as a PHP DOMDocument.
     *
     * @return \DOMDocument
     *   The result of parsing CKEditor 5's data into a PHP DOMDocument.
     */
    protected function getEditorDataAsDom() : \DOMDocument {
        return Html::load($this->getEditorDataAsHtmlString());
    }
    
    /**
     * Gets CKEditor 5 instance data as a HTML string.
     *
     * @return string
     *   The result of retrieving CKEditor 5's data.
     *
     * @see https://ckeditor.com/docs/ckeditor5/latest/api/module_editor-classic_classiceditor-ClassicEditor.html#function-getData
     */
    protected function getEditorDataAsHtmlString() : string {
        // We cannot trust on CKEditor updating the textarea every time model
        // changes. Therefore, the most reliable way to get downcasted data is to
        // use the CKEditor API.
        $javascript = <<<JS
(function(){
  return Drupal.CKEditor5Instances.get(Drupal.CKEditor5Instances.keys().next().value).getData();
})();
JS;
        return $this->getSession()
            ->evaluateScript($javascript);
    }
    
    /**
     * Waits for CKEditor to initialize.
     */
    protected function waitForEditor() {
        $assert_session = $this->assertSession();
        $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-editor'));
    }
    
    /**
     * Clicks a CKEditor button.
     *
     * @param string $name
     *   The name of the button, such as `drupallink`, `source`, etc.
     */
    protected function pressEditorButton($name) {
        $this->getEditorButton($name)
            ->click();
    }
    
    /**
     * Waits for a CKEditor button and returns it when available and visible.
     *
     * @param string $name
     *   The name of the button, such as `drupallink`, `source`, etc.
     *
     * @return \Behat\Mink\Element\NodeElement|null
     *   The page element node if found, NULL if not.
     */
    protected function getEditorButton($name) {
        $button = $this->assertSession()
            ->waitForElementVisible('xpath', "//button[span[text()='{$name}']]");
        $this->assertNotEmpty($button);
        return $button;
    }
    
    /**
     * Asserts a CKEditor button is disabled.
     *
     * @param string $name
     *   The name of the button, such as `drupallink`, `source`, etc.
     */
    protected function assertEditorButtonDisabled($name) {
        $button = $this->getEditorButton($name);
        $this->assertTrue($button->hasAttribute('aria-disabled'));
        $this->assertTrue($button->hasClass('ck-disabled'));
    }
    
    /**
     * Asserts a CKEditor button is enabled.
     *
     * @param string $name
     *   The name of the button, such as `drupallink`, `source`, etc.
     */
    protected function assertEditorButtonEnabled($name) {
        $button = $this->getEditorButton($name);
        $this->assertFalse($button->hasAttribute('aria-disabled'));
        $this->assertFalse($button->hasClass('ck-disabled'));
    }
    
    /**
     * Asserts a particular balloon is visible.
     *
     * @param string $balloon_content_selector
     *   A CSS selector.
     *
     * @return \Behat\Mink\Element\NodeElement
     *   The asserted balloon.
     */
    protected function assertVisibleBalloon(string $balloon_content_selector) : NodeElement {
        $this->assertSession()
            ->elementExists('css', '.ck-balloon-panel_visible');
        $selector = ".ck-balloon-panel_visible .ck-balloon-rotator__content > .ck{$balloon_content_selector}";
        $this->assertSession()
            ->elementExists('css', $selector);
        return $this->getSession()
            ->getPage()
            ->find('css', $selector);
    }
    
    /**
     * Gets a button from the currently visible balloon.
     *
     * @param string $name
     *   The label of the button to find.
     *
     * @return \Behat\Mink\Element\NodeElement
     *   The requested button.
     */
    protected function getBalloonButton(string $name) : NodeElement {
        $button = $this->getSession()
            ->getPage()
            ->find('css', '.ck-balloon-panel_visible .ck-balloon-rotator__content')
            ->find('xpath', "//button[span[text()='{$name}']]");
        $this->assertNotEmpty($button);
        return $button;
    }
    
    /**
     * Selects text inside an element.
     *
     * @param string $selector
     *   A CSS selector for the element which contents should be selected.
     */
    protected function selectTextInsideElement(string $selector) : void {
        $javascript = <<<JS
(function() {
  const el = document.querySelector(".ck-editor__main {<span class="php-variable">$selector</span>}");
  const range = document.createRange();
  range.selectNodeContents(el);
  const sel = window.getSelection();
  sel.removeAllRanges();
  sel.addRange(range);
})();
JS;
        $this->getSession()
            ->evaluateScript($javascript);
    }

}