class HelpTopicsSyntaxTest

class HelpTopicsSyntaxTest extends BrowserTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected static $modules = [
        'help',
        'help_topics_twig_tester',
        'locale',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * Tests that all Core help topics can be rendered and have good syntax.
     */
    public function testHelpTopics() : void {
        $this->drupalLogin($this->createUser([
            'administer modules',
            'access help pages',
        ]));
        // Enable all modules and themes, so that all routes mentioned in topics
        // will be defined.
        $module_directories = $this->listDirectories('module');
        $modules_to_install = array_keys($module_directories);
        \Drupal::service('module_installer')->install($modules_to_install);
        $theme_directories = $this->listDirectories('theme');
        \Drupal::service('theme_installer')->install(array_keys($theme_directories));
        $directories = $module_directories + $theme_directories + $this->listDirectories('profile');
        $directories['core'] = \Drupal::root() . '/core/help_topics';
        $directories['bad_help_topics'] = \Drupal::service('extension.list.module')->getPath('help_topics_test') . '/bad_help_topics/syntax/';
        // Filter out directories outside of core. If you want to run this test
        // on a contrib/custom module, remove the next line.
        $directories = array_filter($directories, function ($directory) {
            return str_starts_with($directory, 'core');
        });
        // Verify that a few key modules, themes, and profiles are listed, so that
        // we can be certain our directory list is complete and we will be testing
        // all existing help topics. If these lines in the test fail in the future,
        // it is probably because something we chose to list here is being removed.
        // Substitute another item of the same type that still exists, so that this
        // test can continue.
        $this->assertArrayHasKey('system', $directories, 'System module is being scanned');
        $this->assertArrayHasKey('help', $directories, 'Help module is being scanned');
        $this->assertArrayHasKey('claro', $directories, 'Claro theme is being scanned');
        $this->assertArrayHasKey('standard', $directories, 'Standard profile is being scanned');
        $definitions = (new HelpTopicDiscovery($directories))->getDefinitions();
        $this->assertGreaterThan(0, count($definitions), 'At least 1 topic was found');
        // Test each topic for compliance with standards, or for failing in the
        // right way.
        foreach (array_keys($definitions) as $id) {
            if (str_starts_with($id, 'bad_help_topics.')) {
                $this->verifyBadTopic($id, $definitions);
            }
            else {
                $this->verifyTopic($id, $definitions);
            }
        }
    }
    
    /**
     * Verifies rendering and standards compliance of one help topic.
     *
     * @param string $id
     *   ID of the topic to verify.
     * @param array $definitions
     *   Array of all topic definitions, keyed by ID.
     * @param int $response
     *   Expected response from visiting the page for the topic.
     */
    protected function verifyTopic($id, $definitions, $response = 200) {
        $definition = $definitions[$id];
        HelpTestTwigNodeVisitor::setStateValue('manner', 0);
        // Visit the URL for the topic.
        $this->drupalGet('admin/help/topic/' . $id);
        // Verify the title and response.
        $session = $this->assertSession();
        $session->statusCodeEquals($response);
        if ($response == 200) {
            $session->titleEquals($definition['label'] . ' | Drupal');
        }
        // Verify that all the related topics exist. Also check to see if any of
        // them are top-level (we will need that in the next section).
        $has_top_level_related = FALSE;
        if (isset($definition['related'])) {
            foreach ($definition['related'] as $related_id) {
                $this->assertArrayHasKey($related_id, $definitions, 'Topic ' . $id . ' is only related to topics that exist: ' . $related_id);
                $has_top_level_related = $has_top_level_related || !empty($definitions[$related_id]['top_level']);
            }
        }
        // Verify this is either top-level or related to a top-level topic.
        $this->assertTrue(!empty($definition['top_level']) || $has_top_level_related, 'Topic ' . $id . ' is either top-level or related to at least one other top-level topic');
        // Verify that the label is not empty.
        $this->assertNotEmpty($definition['label'], 'Topic ' . $id . ' has a non-empty label');
        // Test the syntax and contents of the Twig file (without the front
        // matter, which is tested in other ways above). We need to render the
        // template several times with variations, so read it in once.
        $template = file_get_contents($definition[HelpTopicDiscovery::FILE_KEY]);
        $template_text = FrontMatter::create($template)->getContent();
        // Verify that the body is not empty and is valid HTML.
        $text = $this->renderHelpTopic($template_text, 'bare_body');
        $this->assertNotEmpty($text, 'Topic ' . $id . ' contains some text outside of front matter');
        $this->validateHtml($text, $id);
        $max_chunk_num = HelpTestTwigNodeVisitor::getState()['max_chunk'];
        $this->assertTrue($max_chunk_num >= 0, 'Topic ' . $id . ' has at least one translated chunk');
        // Verify that each chunk of the translated text is locale-safe and
        // valid HTML.
        $chunk_num = 0;
        $number_checked = 0;
        while ($chunk_num <= $max_chunk_num) {
            $chunk_str = $id . ' section ' . $chunk_num;
            // Render the topic, asking for just one chunk, and extract the chunk.
            // Note that some chunks may not actually get rendered, if they are inside
            // set statements, because we skip rendering variable output.
            HelpTestTwigNodeVisitor::setStateValue('return_chunk', $chunk_num);
            $text = $this->renderHelpTopic($template_text, 'translated_chunk');
            $matches = [];
            $matched = preg_match('|' . HelpTestTwigNodeVisitor::DELIMITER . '(.*)' . HelpTestTwigNodeVisitor::DELIMITER . '|', $text, $matches);
            if ($matched) {
                $number_checked++;
                $text = $matches[1];
                $this->assertNotEmpty($text, 'Topic ' . $chunk_str . ' contains text');
                // Verify the chunk is OK.
                $this->assertTrue(locale_string_is_safe($text), 'Topic ' . $chunk_str . ' translatable string is locale-safe');
                $this->validateHtml($text, $chunk_str);
            }
            $chunk_num++;
        }
        $this->assertTrue($number_checked > 0, 'Tested at least one translated chunk in ' . $id);
        // Validate the HTML in the body with the translated text replaced by a
        // dummy string, to verify that HTML syntax is not partly in and partly out
        // of the translated text.
        $text = $this->renderHelpTopic($template_text, 'replace_translated');
        $this->validateHtml($text, $id);
        // Verify that if we remove all the translated text, whitespace, and
        // HTML tags, there is nothing left (that is, all text is translated).
        $text = preg_replace('|\\s+|', '', $this->renderHelpTopic($template_text, 'remove_translated'));
        $this->assertEmpty($text, 'Topic ' . $id . ' Twig file has all of its text translated');
        // Verify that the Twig url() function was not used.
        $this->assertStringNotContainsString('url(', $template, 'Topic ' . $id . ' appears to use the url() function. Replace with help_topic_link() or help_topic_route(). See https://drupal.org/node/3074421');
    }
    
    /**
     * Validates the HTML and header hierarchy for topic text.
     *
     * @param string $body
     *   Body text to validate.
     * @param string $id
     *   ID of help topic (for error messages).
     */
    protected function validateHtml(string $body, string $id) {
        $doc = new \DOMDocument();
        $doc->strictErrorChecking = TRUE;
        $doc->validateOnParse = FALSE;
        libxml_use_internal_errors(TRUE);
        if (!$doc->loadXML('<html><body>' . $body . '</body></html>')) {
            foreach (libxml_get_errors() as $error) {
                $this->fail('Topic ' . $id . ' fails HTML validation: ' . $error->message);
            }
            libxml_clear_errors();
        }
        // Check for headings hierarchy.
        $levels = [
            1,
            2,
            3,
            4,
            5,
            6,
        ];
        foreach ($levels as $level) {
            $num_headings[$level] = $doc->getElementsByTagName('h' . $level)->length;
            if ($level == 1) {
                $this->assertSame(0, $num_headings[1], 'Topic ' . $id . ' has no H1 tag');
                // Set num_headings to 1 for this level, so the rest of the hierarchy
                // can be tested using simpler code.
                $num_headings[1] = 1;
            }
            else {
                // We should either not have this heading, or if we do have one at this
                // level, we should also have the next-smaller level. That is, if we
                // have an h3, we should have also had an h2.
                $this->assertTrue($num_headings[$level - 1] > 0 || $num_headings[$level] == 0, 'Topic ' . $id . ' has the correct H2-H6 heading hierarchy');
            }
        }
    }
    
    /**
     * Verifies that a bad topic fails in the expected way.
     *
     * @param string $id
     *   ID of the topic to verify. It should start with "bad_help_topics.".
     * @param array $definitions
     *   Array of all topic definitions, keyed by ID.
     */
    protected function verifyBadTopic($id, $definitions) {
        $bad_topic_type = substr($id, 16);
        // Topics should fail verifyTopic() in specific ways.
        $found_error = FALSE;
        try {
            $this->verifyTopic($id, $definitions, 404);
        } catch (ExpectationFailedException|AssertionFailedError $e) {
            $found_error = TRUE;
            $message = $e->getMessage();
            switch ($bad_topic_type) {
                case 'related':
                    $this->assertStringContainsString('only related to topics that exist', $message);
                    break;
                case 'bad_html':
                case 'bad_html2':
                case 'bad_html3':
                    $this->assertStringContainsString('Opening and ending tag mismatch', $message);
                    break;
                case 'top_level':
                    $this->assertStringContainsString('is either top-level or related to at least one other top-level topic', $message);
                    break;
                case 'empty':
                    $this->assertStringContainsString('contains some text outside of front matter', $message);
                    break;
                case 'translated':
                    $this->assertStringContainsString('Twig file has all of its text translated', $message);
                    break;
                case 'locale':
                    $this->assertStringContainsString('translatable string is locale-safe', $message);
                    break;
                case 'h1':
                    $this->assertStringContainsString('has no H1 tag', $message);
                    break;
                case 'hierarchy':
                    $this->assertStringContainsString('has the correct H2-H6 heading hierarchy', $message);
                    break;
                case 'url_func_used':
                    $this->assertStringContainsString('appears to use the url() function', $message);
                    break;
                default:
                    // This was an unexpected error.
                    throw $e;
            }
        }
        if (!$found_error) {
            $this->fail('Bad help topic ' . $bad_topic_type . ' did not fail as expected');
        }
    }
    
    /**
     * Lists the extension help topic directories of a certain type.
     *
     * @param string $type
     *   The type of extension to list: module, theme, or profile.
     *
     * @return string[]
     *   An array of all of the help topic directories for this type of
     *   extension, keyed by extension short name.
     */
    protected function listDirectories($type) {
        $directories = [];
        // Find the extensions of this type, even if they are not installed, but
        // excluding test ones.
        $lister = \Drupal::service('extension.list.' . $type);
        foreach ($lister->getAllAvailableInfo() as $name => $info) {
            // Skip obsolete and deprecated modules.
            if ($info[ExtensionLifecycle::LIFECYCLE_IDENTIFIER] === ExtensionLifecycle::OBSOLETE || $info[ExtensionLifecycle::LIFECYCLE_IDENTIFIER] === ExtensionLifecycle::DEPRECATED) {
                continue;
            }
            $path = $lister->getPath($name);
            // You can tell test modules because they are in package 'Testing', but
            // test themes are only known by being found in test directories. So...
            // exclude things in test directories.
            if (!str_contains($path, '/tests') && !str_contains($path, '/testing')) {
                $directories[$name] = $path . '/help_topics';
            }
        }
        return $directories;
    }
    
    /**
     * Renders a help topic in a special manner.
     *
     * @param string $content
     *   Template text, without the front matter.
     * @param string $manner
     *   The special processing choice for topic rendering.
     *
     * @return string
     *   The rendered topic.
     */
    protected function renderHelpTopic(string $content, string $manner) {
        // Set up the special state variables for rendering.
        HelpTestTwigNodeVisitor::setStateValue('manner', $manner);
        HelpTestTwigNodeVisitor::setStateValue('max_chunk', -1);
        HelpTestTwigNodeVisitor::setStateValue('chunk_count', -1);
        // Add a random comment to the end, to thwart caching, and render. We need
        // the HelpTestTwigNodeVisitor class to hit it each time we render.
        $build = [
            '#type' => 'inline_template',
            '#template' => $content . "\n{# " . rand() . " #}",
        ];
        return (string) \Drupal::service('renderer')->renderInIsolation($build);
    }

}