class AjaxFormPageCacheTest

class AjaxFormPageCacheTest extends WebDriverTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected static $modules = [
        'ajax_test',
        'ajax_forms_test',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        $config = $this->config('system.performance');
        $config->set('cache.page.max_age', 300);
        $config->save();
    }
    
    /**
     * Return the build id of the current form.
     */
    protected function getFormBuildId() {
        // Ensure the hidden 'form_build_id' field is unique.
        $this->assertSession()
            ->elementsCount('xpath', '//input[@name="form_build_id"]', 1);
        return $this->assertSession()
            ->hiddenFieldExists('form_build_id')
            ->getValue();
    }
    
    /**
     * Create a simple form, then submit the form via AJAX to change to it.
     */
    public function testSimpleAJAXFormValue() : void {
        $this->drupalGet('ajax_forms_test_get_form');
        $build_id_initial = $this->getFormBuildId();
        // Changing the value of a select input element, triggers an AJAX
        // request/response. The callback on the form responds with three AJAX
        // commands:
        // - UpdateBuildIdCommand
        // - HtmlCommand
        // - DataCommand
        $session = $this->getSession();
        $session->getPage()
            ->selectFieldOption('select', 'green');
        // Wait for the DOM to update. The HtmlCommand will update
        // #ajax_selected_color to reflect the color change.
        $green_span = $this->assertSession()
            ->waitForElement('css', "#ajax_selected_color:contains('green')");
        $this->assertNotNull($green_span, 'DOM update: The selected color SPAN is green.');
        // Confirm the operation of the UpdateBuildIdCommand.
        $build_id_first_ajax = $this->getFormBuildId();
        $this->assertNotEquals($build_id_initial, $build_id_first_ajax, 'Build id is changed in the form_build_id element on first AJAX submission');
        // Changing the value of a select input element, triggers an AJAX
        // request/response.
        $session->getPage()
            ->selectFieldOption('select', 'red');
        // Wait for the DOM to update.
        $red_span = $this->assertSession()
            ->waitForElement('css', "#ajax_selected_color:contains('red')");
        $this->assertNotNull($red_span, 'DOM update: The selected color SPAN is red.');
        // Confirm the operation of the UpdateBuildIdCommand.
        $build_id_second_ajax = $this->getFormBuildId();
        $this->assertNotEquals($build_id_first_ajax, $build_id_second_ajax, 'Build id changes on subsequent AJAX submissions');
        // Emulate a push of the reload button and then repeat the test sequence
        // this time with a page loaded from the cache.
        $session->reload();
        $build_id_from_cache_initial = $this->getFormBuildId();
        $this->assertEquals($build_id_initial, $build_id_from_cache_initial, 'Build id is the same as on the first request');
        // Changing the value of a select input element, triggers an AJAX
        // request/response.
        $session->getPage()
            ->selectFieldOption('select', 'green');
        // Wait for the DOM to update.
        $green_span2 = $this->assertSession()
            ->waitForElement('css', "#ajax_selected_color:contains('green')");
        $this->assertNotNull($green_span2, 'DOM update: After reload - the selected color SPAN is green.');
        $build_id_from_cache_first_ajax = $this->getFormBuildId();
        $this->assertNotEquals($build_id_from_cache_initial, $build_id_from_cache_first_ajax, 'Build id is changed in the DOM on first AJAX submission');
        $this->assertNotEquals($build_id_first_ajax, $build_id_from_cache_first_ajax, 'Build id from first user is not reused');
        // Changing the value of a select input element, triggers an AJAX
        // request/response.
        $session->getPage()
            ->selectFieldOption('select', 'red');
        // Wait for the DOM to update.
        $red_span2 = $this->assertSession()
            ->waitForElement('css', "#ajax_selected_color:contains('red')");
        $this->assertNotNull($red_span2, 'DOM update: After reload - the selected color SPAN is red.');
        $build_id_from_cache_second_ajax = $this->getFormBuildId();
        $this->assertNotEquals($build_id_from_cache_first_ajax, $build_id_from_cache_second_ajax, 'Build id changes on subsequent AJAX submissions');
    }
    
    /**
     * Tests that updating the text field trigger an AJAX request/response.
     *
     * @see \Drupal\system\Tests\Ajax\ElementValidationTest::testAjaxElementValidation()
     */
    public function testAjaxElementValidation() : void {
        $this->drupalGet('ajax_validation_test');
        // Changing the value of the textfield will trigger an AJAX
        // request/response.
        $field = $this->getSession()
            ->getPage()
            ->findField('driver_text');
        $field->setValue('some dumb text');
        $field->blur();
        // When the AJAX command updates the DOM a <ul> unsorted list
        // "message__list" structure will appear on the page echoing back the
        // "some dumb text" message.
        $placeholder = $this->assertSession()
            ->waitForElement('css', "[aria-label='Status message'] > ul > li > em:contains('some dumb text')");
        $this->assertNotNull($placeholder, 'Message structure containing input data located.');
    }

}