class SystemController

class SystemController extends ControllerBase {
    use ModuleDependencyMessageTrait;
    
    /**
     * System Manager Service.
     *
     * @var \Drupal\system\SystemManager
     */
    protected $systemManager;
    
    /**
     * The theme access checker service.
     *
     * @var \Drupal\Core\Theme\ThemeAccessCheck
     */
    protected $themeAccess;
    
    /**
     * The form builder service.
     *
     * @var \Drupal\Core\Form\FormBuilderInterface
     */
    protected $formBuilder;
    
    /**
     * The theme handler service.
     *
     * @var \Drupal\Core\Extension\ThemeHandlerInterface
     */
    protected $themeHandler;
    
    /**
     * The menu link tree service.
     *
     * @var \Drupal\Core\Menu\MenuLinkTreeInterface
     */
    protected $menuLinkTree;
    
    /**
     * The module extension list.
     *
     * @var \Drupal\Core\Extension\ModuleExtensionList
     */
    protected $moduleExtensionList;
    
    /**
     * Constructs a new SystemController.
     *
     * @param \Drupal\system\SystemManager $systemManager
     *   System manager service.
     * @param \Drupal\Core\Theme\ThemeAccessCheck $theme_access
     *   The theme access checker service.
     * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
     *   The form builder.
     * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
     *   The theme handler.
     * @param \Drupal\Core\Menu\MenuLinkTreeInterface $menu_link_tree
     *   The menu link tree service.
     * @param \Drupal\Core\Extension\ModuleExtensionList $module_extension_list
     *   The module extension list.
     */
    public function __construct(SystemManager $systemManager, ThemeAccessCheck $theme_access, FormBuilderInterface $form_builder, ThemeHandlerInterface $theme_handler, MenuLinkTreeInterface $menu_link_tree, ModuleExtensionList $module_extension_list = NULL) {
        $this->systemManager = $systemManager;
        $this->themeAccess = $theme_access;
        $this->formBuilder = $form_builder;
        $this->themeHandler = $theme_handler;
        $this->menuLinkTree = $menu_link_tree;
        if ($module_extension_list === NULL) {
            @trigger_error('The extension.list.module service must be passed to ' . __NAMESPACE__ . '\\SystemController::__construct. It was added in Drupal 8.9.0 and will be required before Drupal 10.0.0.', E_USER_DEPRECATED);
            $module_extension_list = \Drupal::service('extension.list.module');
        }
        $this->moduleExtensionList = $module_extension_list;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('system.manager'), $container->get('access_check.theme'), $container->get('form_builder'), $container->get('theme_handler'), $container->get('menu.link_tree'), $container->get('extension.list.module'));
    }
    
    /**
     * Provide the administration overview page.
     *
     * @param string $link_id
     *   The ID of the administrative path link for which to display child links.
     *
     * @return array
     *   A renderable array of the administration overview page.
     */
    public function overview($link_id) {
        // Check for status report errors.
        if ($this->systemManager
            ->checkRequirements() && $this->currentUser()
            ->hasPermission('administer site configuration')) {
            $this->messenger()
                ->addError($this->t('One or more problems were detected with your Drupal installation. Check the <a href=":status">status report</a> for more information.', [
                ':status' => Url::fromRoute('system.status')->toString(),
            ]));
        }
        // Load all menu links below it.
        $parameters = new MenuTreeParameters();
        $parameters->setRoot($link_id)
            ->excludeRoot()
            ->setTopLevelOnly()
            ->onlyEnabledLinks();
        $tree = $this->menuLinkTree
            ->load(NULL, $parameters);
        $manipulators = [
            [
                'callable' => 'menu.default_tree_manipulators:checkAccess',
            ],
            [
                'callable' => 'menu.default_tree_manipulators:generateIndexAndSort',
            ],
        ];
        $tree = $this->menuLinkTree
            ->transform($tree, $manipulators);
        $tree_access_cacheability = new CacheableMetadata();
        $blocks = [];
        foreach ($tree as $key => $element) {
            $tree_access_cacheability = $tree_access_cacheability->merge(CacheableMetadata::createFromObject($element->access));
            // Only render accessible links.
            if (!$element->access
                ->isAllowed()) {
                continue;
            }
            $link = $element->link;
            $block['title'] = $link->getTitle();
            $block['description'] = $link->getDescription();
            $block['content'] = [
                '#theme' => 'admin_block_content',
                '#content' => $this->systemManager
                    ->getAdminBlock($link),
            ];
            if (!empty($block['content']['#content'])) {
                $blocks[$key] = $block;
            }
        }
        if ($blocks) {
            ksort($blocks);
            $build = [
                '#theme' => 'admin_page',
                '#blocks' => $blocks,
            ];
            $tree_access_cacheability->applyTo($build);
            return $build;
        }
        else {
            $build = [
                '#markup' => $this->t('You do not have any administrative items.'),
            ];
            $tree_access_cacheability->applyTo($build);
            return $build;
        }
    }
    
    /**
     * Sets whether the admin menu is in compact mode or not.
     *
     * @param string $mode
     *   Valid values are 'on' and 'off'.
     *
     * @return \Symfony\Component\HttpFoundation\RedirectResponse
     */
    public function compactPage($mode) {
        user_cookie_save([
            'admin_compact_mode' => $mode == 'on',
        ]);
        return $this->redirect('<front>');
    }
    
    /**
     * Provides a single block from the administration menu as a page.
     */
    public function systemAdminMenuBlockPage() {
        return $this->systemManager
            ->getBlockContents();
    }
    
    /**
     * Returns a theme listing.
     *
     * @return string
     *   An HTML string of the theme listing page.
     *
     * @todo Move into ThemeController.
     */
    public function themesPage() {
        $config = $this->config('system.theme');
        // Get all available themes.
        $themes = $this->themeHandler
            ->rebuildThemeData();
        uasort($themes, 'system_sort_modules_by_info_name');
        $theme_default = $config->get('default');
        $theme_groups = [
            'installed' => [],
            'uninstalled' => [],
        ];
        $admin_theme = $config->get('admin');
        $admin_theme_options = [];
        foreach ($themes as &$theme) {
            if (!empty($theme->info['hidden'])) {
                continue;
            }
            $theme->is_default = $theme->getName() == $theme_default;
            $theme->is_admin = $theme->getName() == $admin_theme || $theme->is_default && empty($admin_theme);
            $theme->is_experimental = isset($theme->info['experimental']) && $theme->info['experimental'];
            // Identify theme screenshot.
            $theme->screenshot = NULL;
            // Create a list which includes the current theme and all its base themes.
            if (isset($themes[$theme->getName()]->base_themes)) {
                $theme_keys = array_keys($themes[$theme->getName()]->base_themes);
                $theme_keys[] = $theme->getName();
            }
            else {
                $theme_keys = [
                    $theme->getName(),
                ];
            }
            // Look for a screenshot in the current theme or in its closest ancestor.
            foreach (array_reverse($theme_keys) as $theme_key) {
                if (isset($themes[$theme_key]) && file_exists($themes[$theme_key]->info['screenshot'])) {
                    $theme->screenshot = [
                        'uri' => $themes[$theme_key]->info['screenshot'],
                        'alt' => $this->t('Screenshot for @theme theme', [
                            '@theme' => $theme->info['name'],
                        ]),
                        'title' => $this->t('Screenshot for @theme theme', [
                            '@theme' => $theme->info['name'],
                        ]),
                        'attributes' => [
                            'class' => [
                                'screenshot',
                            ],
                        ],
                    ];
                    break;
                }
            }
            if (empty($theme->status)) {
                // Require the 'content' region to make sure the main page
                // content has a common place in all themes.
                $theme->incompatible_region = !isset($theme->info['regions']['content']);
                $theme->incompatible_php = version_compare(phpversion(), $theme->info['php']) < 0;
                // Confirm that all base themes are available.
                $theme->incompatible_base = isset($theme->info['base theme']) && !($theme->base_themes === array_filter($theme->base_themes));
                // Confirm that the theme engine is available.
                $theme->incompatible_engine = isset($theme->info['engine']) && !isset($theme->owner);
                // Confirm that module dependencies are available.
                $theme->incompatible_module = FALSE;
                // Confirm that the user has permission to enable modules.
                $theme->insufficient_module_permissions = FALSE;
            }
            // Check module dependencies.
            if ($theme->module_dependencies) {
                $modules = $this->moduleExtensionList
                    ->getList();
                foreach ($theme->module_dependencies as $dependency => $dependency_object) {
                    if ($incompatible = $this->checkDependencyMessage($modules, $dependency, $dependency_object)) {
                        $theme->module_dependencies_list[$dependency] = $incompatible;
                        $theme->incompatible_module = TRUE;
                        continue;
                    }
                    // @todo Add logic for not displaying hidden modules in
                    //   https://drupal.org/node/3117829.
                    $module_name = $modules[$dependency]->info['name'];
                    $theme->module_dependencies_list[$dependency] = $modules[$dependency]->status ? $this->t('@module_name', [
                        '@module_name' => $module_name,
                    ]) : $this->t('@module_name (<span class="admin-disabled">disabled</span>)', [
                        '@module_name' => $module_name,
                    ]);
                    // Create an additional property that contains only disabled module
                    // dependencies. This will determine if it is possible to install the
                    // theme, or if modules must first be enabled.
                    if (!$modules[$dependency]->status) {
                        $theme->module_dependencies_disabled[$dependency] = $module_name;
                        if (!$this->currentUser()
                            ->hasPermission('administer modules')) {
                            $theme->insufficient_module_permissions = TRUE;
                        }
                    }
                }
            }
            $theme->operations = [];
            if (!empty($theme->status) || !$theme->info['core_incompatible'] && !$theme->incompatible_php && !$theme->incompatible_base && !$theme->incompatible_engine && !$theme->incompatible_module && empty($theme->module_dependencies_disabled)) {
                // Create the operations links.
                $query['theme'] = $theme->getName();
                if ($this->themeAccess
                    ->checkAccess($theme->getName())) {
                    $theme->operations[] = [
                        'title' => $this->t('Settings'),
                        'url' => Url::fromRoute('system.theme_settings_theme', [
                            'theme' => $theme->getName(),
                        ]),
                        'attributes' => [
                            'title' => $this->t('Settings for @theme theme', [
                                '@theme' => $theme->info['name'],
                            ]),
                        ],
                    ];
                }
                if (!empty($theme->status)) {
                    if (!$theme->is_default) {
                        $theme_uninstallable = TRUE;
                        if ($theme->getName() == $admin_theme) {
                            $theme_uninstallable = FALSE;
                        }
                        // Check it isn't the base of theme of an installed theme.
                        foreach ($theme->required_by as $themename => $dependency) {
                            if (!empty($themes[$themename]->status)) {
                                $theme_uninstallable = FALSE;
                            }
                        }
                        if ($theme_uninstallable) {
                            $theme->operations[] = [
                                'title' => $this->t('Uninstall'),
                                'url' => Url::fromRoute('system.theme_uninstall'),
                                'query' => $query,
                                'attributes' => [
                                    'title' => $this->t('Uninstall @theme theme', [
                                        '@theme' => $theme->info['name'],
                                    ]),
                                ],
                            ];
                        }
                        $theme->operations[] = [
                            'title' => $this->t('Set as default'),
                            'url' => Url::fromRoute('system.theme_set_default'),
                            'query' => $query,
                            'attributes' => [
                                'title' => $this->t('Set @theme as default theme', [
                                    '@theme' => $theme->info['name'],
                                ]),
                            ],
                        ];
                    }
                    $admin_theme_options[$theme->getName()] = $theme->info['name'] . ($theme->is_experimental ? ' (' . t('Experimental') . ')' : '');
                }
                else {
                    $theme->operations[] = [
                        'title' => $this->t('Install'),
                        'url' => Url::fromRoute('system.theme_install'),
                        'query' => $query,
                        'attributes' => [
                            'title' => $this->t('Install @theme theme', [
                                '@theme' => $theme->info['name'],
                            ]),
                        ],
                    ];
                    $theme->operations[] = [
                        'title' => $this->t('Install and set as default'),
                        'url' => Url::fromRoute('system.theme_set_default'),
                        'query' => $query,
                        'attributes' => [
                            'title' => $this->t('Install @theme as default theme', [
                                '@theme' => $theme->info['name'],
                            ]),
                        ],
                    ];
                }
            }
            // Add notes to default theme, administration theme and experimental
            // themes.
            $theme->notes = [];
            if ($theme->is_default) {
                $theme->notes[] = $this->t('default theme');
            }
            if ($theme->is_admin) {
                $theme->notes[] = $this->t('administration theme');
            }
            if ($theme->is_experimental) {
                $theme->notes[] = $this->t('experimental theme');
            }
            // Sort installed and uninstalled themes into their own groups.
            $theme_groups[$theme->status ? 'installed' : 'uninstalled'][] = $theme;
        }
        // There are two possible theme groups.
        $theme_group_titles = [
            'installed' => $this->formatPlural(count($theme_groups['installed']), 'Installed theme', 'Installed themes'),
        ];
        if (!empty($theme_groups['uninstalled'])) {
            $theme_group_titles['uninstalled'] = $this->formatPlural(count($theme_groups['uninstalled']), 'Uninstalled theme', 'Uninstalled themes');
        }
        uasort($theme_groups['installed'], 'system_sort_themes');
        $this->moduleHandler()
            ->alter('system_themes_page', $theme_groups);
        $build = [];
        $build[] = [
            '#theme' => 'system_themes_page',
            '#theme_groups' => $theme_groups,
            '#theme_group_titles' => $theme_group_titles,
        ];
        $build[] = $this->formBuilder
            ->getForm('Drupal\\system\\Form\\ThemeAdminForm', $admin_theme_options);
        return $build;
    }

}