class BigPipeTestController

class BigPipeTestController implements TrustedCallbackInterface {
    
    /**
     * Returns all BigPipe placeholder test case render arrays.
     *
     * @return array
     */
    public function test() {
        $has_session = \Drupal::service('session_configuration')->hasSession(\Drupal::requestStack()->getMainRequest());
        $build = [];
        $cases = BigPipePlaceholderTestCases::cases(\Drupal::getContainer());
        // 1. HTML placeholder: status messages. Drupal renders those automatically,
        // so all that we need to do in this controller is set a message.
        if ($has_session) {
            // Only set a message if a session already exists, otherwise we always
            // trigger a session, which means we can't test no-session requests.
            \Drupal::messenger()->addStatus('Hello from BigPipe!');
        }
        $build['html'] = $cases['html']->renderArray;
        // 2. HTML attribute value placeholder: form action.
        $build['html_attribute_value'] = $cases['html_attribute_value']->renderArray;
        // 3. HTML attribute value subset placeholder: CSRF token in link.
        $build['html_attribute_value_subset'] = $cases['html_attribute_value_subset']->renderArray;
        // 4. Edge case: custom string to be considered as a placeholder that
        // happens to not be valid HTML.
        $build['edge_case__invalid_html'] = $cases['edge_case__invalid_html']->renderArray;
        // 5. Edge case: non-#lazy_builder placeholder.
        $build['edge_case__html_non_lazy_builder'] = $cases['edge_case__html_non_lazy_builder']->renderArray;
        // 6. Exception: #lazy_builder that throws an exception.
        $build['exception__lazy_builder'] = $cases['exception__lazy_builder']->renderArray;
        // 7. Exception: placeholder that causes response filter to throw exception.
        $build['exception__embedded_response'] = $cases['exception__embedded_response']->renderArray;
        return $build;
    }
    
    /**
     * @return array
     */
    public static function nope() {
        return [
            '#markup' => '<p>Nope.</p>',
        ];
    }
    
    /**
     * A page with multiple occurrences of the same placeholder.
     *
     * @see \Drupal\Tests\big_pipe\Functional\BigPipeTest::testBigPipeMultiOccurrencePlaceholders()
     *
     * @return array
     */
    public function multiOccurrence() {
        return [
            'item1' => [
                '#lazy_builder' => [
                    static::class . '::counter',
                    [],
                ],
                '#create_placeholder' => TRUE,
            ],
            'item2' => [
                '#lazy_builder' => [
                    static::class . '::counter',
                    [],
                ],
                '#create_placeholder' => TRUE,
            ],
            'item3' => [
                '#lazy_builder' => [
                    static::class . '::counter',
                    [],
                ],
                '#create_placeholder' => TRUE,
            ],
        ];
    }
    
    /**
     * #lazy_builder callback; builds <time> markup with current time.
     *
     * Note: does not actually use current time, that would complicate testing.
     *
     * @return array
     */
    public static function currentTime() {
        return [
            '#markup' => '<time datetime="' . date('Y-m-d', 668948400) . '"></time>',
            '#cache' => [
                'max-age' => 0,
            ],
        ];
    }
    
    /**
     * #lazy_builder callback; says "hello" or "yarhar".
     *
     * @return array
     */
    public static function helloOrYarhar() {
        return [
            '#markup' => BigPipeMarkup::create('<marquee>Yarhar llamas forever!</marquee>'),
            '#cache' => [
                'max-age' => 0,
                'tags' => [
                    'cache_tag_set_in_lazy_builder',
                ],
            ],
        ];
    }
    
    /**
     * #lazy_builder callback; throws exception.
     *
     * @throws \Exception
     */
    public static function exception() {
        throw new \Exception('You are not allowed to say llamas are not cool!');
    }
    
    /**
     * #lazy_builder callback; returns content that will trigger an exception.
     *
     * @see \Drupal\big_pipe_test\EventSubscriber\BigPipeTestSubscriber::onRespondTriggerException()
     *
     * @return array
     */
    public static function responseException() {
        return [
            '#plain_text' => BigPipeTestSubscriber::CONTENT_TRIGGER_EXCEPTION,
        ];
    }
    
    /**
     * #lazy_builder callback; returns the current count.
     *
     * @see \Drupal\Tests\big_pipe\Functional\BigPipeTest::testBigPipeMultiOccurrencePlaceholders()
     *
     * @return array
     *   The render array.
     */
    public static function counter() {
        // Lazy builders are not allowed to build their own state like this function
        // does, but in this case we're intentionally doing that for testing
        // purposes: so we can ensure that each lazy builder is only ever called
        // once with the same parameters.
        static $count;
        if (!isset($count)) {
            $count = 0;
        }
        $count++;
        return [
            '#markup' => BigPipeMarkup::create("<p>The count is {$count}.</p>"),
            '#cache' => [
                'max-age' => 0,
            ],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public static function trustedCallbacks() {
        return [
            'currentTime',
            'helloOrYarhar',
            'exception',
            'responseException',
            'counter',
        ];
    }

}