class ModuleInstaller

class ModuleInstaller implements ModuleInstallerInterface {
    
    /**
     * The module handler.
     *
     * @var \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected $moduleHandler;
    
    /**
     * The drupal kernel.
     *
     * @var \Drupal\Core\DrupalKernelInterface
     */
    protected $kernel;
    
    /**
     * The app root.
     *
     * @var string
     */
    protected $root;
    
    /**
     * The uninstall validators.
     *
     * @var \Drupal\Core\Extension\ModuleUninstallValidatorInterface[]
     */
    protected $uninstallValidators;
    
    /**
     * Constructs a new ModuleInstaller instance.
     *
     * @param string $root
     *   The app root.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler.
     * @param \Drupal\Core\DrupalKernelInterface $kernel
     *   The drupal kernel.
     *
     * @see \Drupal\Core\DrupalKernel
     * @see \Drupal\Core\CoreServiceProvider
     */
    public function __construct($root, ModuleHandlerInterface $module_handler, DrupalKernelInterface $kernel) {
        $this->root = $root;
        $this->moduleHandler = $module_handler;
        $this->kernel = $kernel;
    }
    
    /**
     * {@inheritdoc}
     */
    public function addUninstallValidator(ModuleUninstallValidatorInterface $uninstall_validator) {
        $this->uninstallValidators[] = $uninstall_validator;
    }
    
    /**
     * {@inheritdoc}
     */
    public function install(array $module_list, $enable_dependencies = TRUE) {
        $extension_config = \Drupal::configFactory()->getEditable('core.extension');
        // Get all module data so we can find dependencies and sort and find the
        // core requirements. The module list needs to be reset so that it can
        // re-scan and include any new modules that may have been added directly
        // into the filesystem.
        $module_data = \Drupal::service('extension.list.module')->reset()
            ->getList();
        foreach ($module_list as $module) {
            if (!empty($module_data[$module]->info['core_incompatible'])) {
                throw new MissingDependencyException("Unable to install modules: module '{$module}' is incompatible with this version of Drupal core.");
            }
        }
        if ($enable_dependencies) {
            $module_list = $module_list ? array_combine($module_list, $module_list) : [];
            if ($missing_modules = array_diff_key($module_list, $module_data)) {
                // One or more of the given modules doesn't exist.
                throw new MissingDependencyException(sprintf('Unable to install modules %s due to missing modules %s.', implode(', ', $module_list), implode(', ', $missing_modules)));
            }
            // Only process currently uninstalled modules.
            $installed_modules = $extension_config->get('module') ?: [];
            if (!($module_list = array_diff_key($module_list, $installed_modules))) {
                // Nothing to do. All modules already installed.
                return TRUE;
            }
            // Add dependencies to the list. The new modules will be processed as
            // the foreach loop continues.
            foreach ($module_list as $module => $value) {
                foreach (array_keys($module_data[$module]->requires) as $dependency) {
                    if (!isset($module_data[$dependency])) {
                        // The dependency does not exist.
                        throw new MissingDependencyException("Unable to install modules: module '{$module}' is missing its dependency module {$dependency}.");
                    }
                    // Skip already installed modules.
                    if (!isset($module_list[$dependency]) && !isset($installed_modules[$dependency])) {
                        if ($module_data[$dependency]->info['core_incompatible']) {
                            throw new MissingDependencyException("Unable to install modules: module '{$module}'. Its dependency module '{$dependency}' is incompatible with this version of Drupal core.");
                        }
                        $module_list[$dependency] = $dependency;
                    }
                }
            }
            // Set the actual module weights.
            $module_list = array_map(function ($module) use ($module_data) {
                return $module_data[$module]->sort;
            }, $module_list);
            // Sort the module list by their weights (reverse).
            arsort($module_list);
            $module_list = array_keys($module_list);
        }
        // Required for module installation checks.
        include_once $this->root . '/core/includes/install.inc';
        
        /** @var \Drupal\Core\Config\ConfigInstaller $config_installer */
        $config_installer = \Drupal::service('config.installer');
        $sync_status = $config_installer->isSyncing();
        if ($sync_status) {
            $source_storage = $config_installer->getSourceStorage();
        }
        $modules_installed = [];
        foreach ($module_list as $module) {
            $enabled = $extension_config->get("module.{$module}") !== NULL;
            if (!$enabled) {
                // Throw an exception if the module name is too long.
                if (strlen($module) > DRUPAL_EXTENSION_NAME_MAX_LENGTH) {
                    throw new ExtensionNameLengthException("Module name '{$module}' is over the maximum allowed length of " . DRUPAL_EXTENSION_NAME_MAX_LENGTH . ' characters');
                }
                // Load a new config object for each iteration, otherwise changes made
                // in hook_install() are not reflected in $extension_config.
                $extension_config = \Drupal::configFactory()->getEditable('core.extension');
                // Check the validity of the default configuration. This will throw
                // exceptions if the configuration is not valid.
                $config_installer->checkConfigurationToInstall('module', $module);
                // Save this data without checking schema. This is a performance
                // improvement for module installation.
                $extension_config->set("module.{$module}", 0)
                    ->set('module', module_config_sort($extension_config->get('module')))
                    ->save(TRUE);
                // Prepare the new module list, sorted by weight, including filenames.
                // This list is used for both the ModuleHandler and DrupalKernel. It
                // needs to be kept in sync between both. A DrupalKernel reboot or
                // rebuild will automatically re-instantiate a new ModuleHandler that
                // uses the new module list of the kernel. However, DrupalKernel does
                // not cause any modules to be loaded.
                // Furthermore, the currently active (fixed) module list can be
                // different from the configured list of enabled modules. For all active
                // modules not contained in the configured enabled modules, we assume a
                // weight of 0.
                $current_module_filenames = $this->moduleHandler
                    ->getModuleList();
                $current_modules = array_fill_keys(array_keys($current_module_filenames), 0);
                $current_modules = module_config_sort(array_merge($current_modules, $extension_config->get('module')));
                $module_filenames = [];
                foreach ($current_modules as $name => $weight) {
                    if (isset($current_module_filenames[$name])) {
                        $module_filenames[$name] = $current_module_filenames[$name];
                    }
                    else {
                        $module_path = \Drupal::service('extension.list.module')->getPath($name);
                        $pathname = "{$module_path}/{$name}.info.yml";
                        $filename = file_exists($module_path . "/{$name}.module") ? "{$name}.module" : NULL;
                        $module_filenames[$name] = new Extension($this->root, 'module', $pathname, $filename);
                    }
                }
                // Update the module handler in order to have the correct module list
                // for the kernel update.
                $this->moduleHandler
                    ->setModuleList($module_filenames);
                // Clear the static cache of the "extension.list.module" service to pick
                // up the new module, since it merges the installation status of modules
                // into its statically cached list.
                \Drupal::service('extension.list.module')->reset();
                // Update the kernel to include it.
                $this->updateKernel($module_filenames);
                // Load the module's .module and .install files.
                $this->moduleHandler
                    ->load($module);
                module_load_install($module);
                // Replace the route provider service with a version that will rebuild
                // if routes used during installation. This ensures that a module's
                // routes are available during installation. This has to occur before
                // any services that depend on it are instantiated otherwise those
                // services will have the old route provider injected. Note that, since
                // the container is rebuilt by updating the kernel, the route provider
                // service is the regular one even though we are in a loop and might
                // have replaced it before.
                \Drupal::getContainer()->set('router.route_provider.old', \Drupal::service('router.route_provider'));
                \Drupal::getContainer()->set('router.route_provider', \Drupal::service('router.route_provider.lazy_builder'));
                // Allow modules to react prior to the installation of a module.
                $this->moduleHandler
                    ->invokeAll('module_preinstall', [
                    $module,
                ]);
                // Now install the module's schema if necessary.
                drupal_install_schema($module);
                // Clear plugin manager caches.
                \Drupal::getContainer()->get('plugin.cache_clearer')
                    ->clearCachedDefinitions();
                // Set the schema version to the number of the last update provided by
                // the module, or the minimum core schema version.
                $version = \Drupal::CORE_MINIMUM_SCHEMA_VERSION;
                $versions = drupal_get_schema_versions($module);
                if ($versions) {
                    $version = max(max($versions), $version);
                }
                // Notify interested components that this module's entity types and
                // field storage definitions are new. For example, a SQL-based storage
                // handler can use this as an opportunity to create the necessary
                // database tables.
                // @todo Clean this up in https://www.drupal.org/node/2350111.
                $entity_type_manager = \Drupal::entityTypeManager();
                $update_manager = \Drupal::entityDefinitionUpdateManager();
                
                /** @var \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager */
                $entity_field_manager = \Drupal::service('entity_field.manager');
                foreach ($entity_type_manager->getDefinitions() as $entity_type) {
                    $is_fieldable_entity_type = $entity_type->entityClassImplements(FieldableEntityInterface::class);
                    if ($entity_type->getProvider() == $module) {
                        if ($is_fieldable_entity_type) {
                            $update_manager->installFieldableEntityType($entity_type, $entity_field_manager->getFieldStorageDefinitions($entity_type->id()));
                        }
                        else {
                            $update_manager->installEntityType($entity_type);
                        }
                    }
                    elseif ($is_fieldable_entity_type) {
                        // The module being installed may be adding new fields to existing
                        // entity types. Field definitions for any entity type defined by
                        // the module are handled in the if branch.
                        foreach ($entity_field_manager->getFieldStorageDefinitions($entity_type->id()) as $storage_definition) {
                            if ($storage_definition->getProvider() == $module) {
                                // If the module being installed is also defining a storage key
                                // for the entity type, the entity schema may not exist yet. It
                                // will be created later in that case.
                                try {
                                    $update_manager->installFieldStorageDefinition($storage_definition->getName(), $entity_type->id(), $module, $storage_definition);
                                } catch (EntityStorageException $e) {
                                    watchdog_exception('system', $e, 'An error occurred while notifying the creation of the @name field storage definition: "!message" in %function (line %line of %file).', [
                                        '@name' => $storage_definition->getName(),
                                    ]);
                                }
                            }
                        }
                    }
                }
                // Install default configuration of the module.
                $config_installer = \Drupal::service('config.installer');
                if ($sync_status) {
                    $config_installer->setSyncing(TRUE)
                        ->setSourceStorage($source_storage);
                }
                \Drupal::service('config.installer')->installDefaultConfig('module', $module);
                // If the module has no current updates, but has some that were
                // previously removed, set the version to the value of
                // hook_update_last_removed().
                if ($last_removed = $this->moduleHandler
                    ->invoke($module, 'update_last_removed')) {
                    $version = max($version, $last_removed);
                }
                drupal_set_installed_schema_version($module, $version);
                // Ensure that all post_update functions are registered already. This
                // should include existing post-updates, as well as any specified as
                // having been previously removed, to ensure that newly installed and
                // updated sites have the same entries in the registry.
                
                /** @var \Drupal\Core\Update\UpdateRegistry $post_update_registry */
                $post_update_registry = \Drupal::service('update.post_update_registry');
                $post_update_registry->registerInvokedUpdates(array_merge($post_update_registry->getModuleUpdateFunctions($module), array_keys($post_update_registry->getRemovedPostUpdates($module))));
                // Record the fact that it was installed.
                $modules_installed[] = $module;
                // Drupal's stream wrappers needs to be re-registered in case a
                // module-provided stream wrapper is used later in the same request. In
                // particular, this happens when installing Drupal via Drush, as the
                // 'translations' stream wrapper is provided by Interface Translation
                // module and is later used to import translations.
                \Drupal::service('stream_wrapper_manager')->register();
                // Update the theme registry to include it.
                drupal_theme_rebuild();
                // Modules can alter theme info, so refresh theme data.
                // @todo ThemeHandler cannot be injected into ModuleHandler, since that
                //   causes a circular service dependency.
                // @see https://www.drupal.org/node/2208429
                \Drupal::service('theme_handler')->refreshInfo();
                // Allow the module to perform install tasks.
                $this->moduleHandler
                    ->invoke($module, 'install', [
                    $sync_status,
                ]);
                // Record the fact that it was installed.
                \Drupal::logger('system')->info('%module module installed.', [
                    '%module' => $module,
                ]);
            }
        }
        // If any modules were newly installed, invoke hook_modules_installed().
        if (!empty($modules_installed)) {
            // If the container was rebuilt during hook_install() it might not have
            // the 'router.route_provider.old' service.
            if (\Drupal::hasService('router.route_provider.old')) {
                \Drupal::getContainer()->set('router.route_provider', \Drupal::service('router.route_provider.old'));
            }
            if (!\Drupal::service('router.route_provider.lazy_builder')->hasRebuilt()) {
                // Rebuild routes after installing module. This is done here on top of
                // \Drupal\Core\Routing\RouteBuilder::destruct to not run into errors on
                // fastCGI which executes ::destruct() after the module installation
                // page was sent already.
                \Drupal::service('router.builder')->rebuild();
            }
            $this->moduleHandler
                ->invokeAll('modules_installed', [
                $modules_installed,
                $sync_status,
            ]);
        }
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
        // Get all module data so we can find dependencies and sort.
        $module_data = \Drupal::service('extension.list.module')->getList();
        $sync_status = \Drupal::service('config.installer')->isSyncing();
        $module_list = $module_list ? array_combine($module_list, $module_list) : [];
        if (array_diff_key($module_list, $module_data)) {
            // One or more of the given modules doesn't exist.
            return FALSE;
        }
        $extension_config = \Drupal::configFactory()->getEditable('core.extension');
        $installed_modules = $extension_config->get('module') ?: [];
        if (!($module_list = array_intersect_key($module_list, $installed_modules))) {
            // Nothing to do. All modules already uninstalled.
            return TRUE;
        }
        if ($uninstall_dependents) {
            $theme_list = \Drupal::service('extension.list.theme')->getList();
            // Add dependent modules to the list. The new modules will be processed as
            // the foreach loop continues.
            foreach ($module_list as $module => $value) {
                foreach (array_keys($module_data[$module]->required_by) as $dependent) {
                    if (!isset($module_data[$dependent]) && !isset($theme_list[$dependent])) {
                        // The dependent module or theme does not exist.
                        return FALSE;
                    }
                    // Skip already uninstalled modules.
                    if (isset($installed_modules[$dependent]) && !isset($module_list[$dependent])) {
                        $module_list[$dependent] = $dependent;
                    }
                }
            }
        }
        // Use the validators and throw an exception with the reasons.
        if ($reasons = $this->validateUninstall($module_list)) {
            foreach ($reasons as $reason) {
                $reason_message[] = implode(', ', $reason);
            }
            throw new ModuleUninstallValidatorException('The following reasons prevent the modules from being uninstalled: ' . implode('; ', $reason_message));
        }
        // Set the actual module weights.
        $module_list = array_map(function ($module) use ($module_data) {
            return $module_data[$module]->sort;
        }, $module_list);
        // Sort the module list by their weights.
        asort($module_list);
        $module_list = array_keys($module_list);
        // Only process modules that are enabled. A module is only enabled if it is
        // configured as enabled. Custom or overridden module handlers might contain
        // the module already, which means that it might be loaded, but not
        // necessarily installed.
        foreach ($module_list as $module) {
            // Clean up all entity bundles (including fields) of every entity type
            // provided by the module that is being uninstalled.
            // @todo Clean this up in https://www.drupal.org/node/2350111.
            $entity_type_manager = \Drupal::entityTypeManager();
            $entity_type_bundle_info = \Drupal::service('entity_type.bundle.info');
            foreach ($entity_type_manager->getDefinitions() as $entity_type_id => $entity_type) {
                if ($entity_type->getProvider() == $module) {
                    foreach (array_keys($entity_type_bundle_info->getBundleInfo($entity_type_id)) as $bundle) {
                        \Drupal::service('entity_bundle.listener')->onBundleDelete($bundle, $entity_type_id);
                    }
                }
            }
            // Allow modules to react prior to the uninstallation of a module.
            $this->moduleHandler
                ->invokeAll('module_preuninstall', [
                $module,
            ]);
            // Uninstall the module.
            module_load_install($module);
            $this->moduleHandler
                ->invoke($module, 'uninstall', [
                $sync_status,
            ]);
            // Remove all configuration belonging to the module.
            \Drupal::service('config.manager')->uninstall('module', $module);
            // In order to make uninstalling transactional if anything uses routes.
            \Drupal::getContainer()->set('router.route_provider.old', \Drupal::service('router.route_provider'));
            \Drupal::getContainer()->set('router.route_provider', \Drupal::service('router.route_provider.lazy_builder'));
            // Notify interested components that this module's entity types are being
            // deleted. For example, a SQL-based storage handler can use this as an
            // opportunity to drop the corresponding database tables.
            // @todo Clean this up in https://www.drupal.org/node/2350111.
            $update_manager = \Drupal::entityDefinitionUpdateManager();
            
            /** @var \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager */
            $entity_field_manager = \Drupal::service('entity_field.manager');
            foreach ($entity_type_manager->getDefinitions() as $entity_type) {
                if ($entity_type->getProvider() == $module) {
                    $update_manager->uninstallEntityType($entity_type);
                }
                elseif ($entity_type->entityClassImplements(FieldableEntityInterface::CLASS)) {
                    // The module being uninstalled might have added new fields to
                    // existing entity types. This will add them to the deleted fields
                    // repository so their data will be purged on cron.
                    foreach ($entity_field_manager->getFieldStorageDefinitions($entity_type->id()) as $storage_definition) {
                        if ($storage_definition->getProvider() == $module) {
                            $update_manager->uninstallFieldStorageDefinition($storage_definition);
                        }
                    }
                }
            }
            // Remove the schema.
            drupal_uninstall_schema($module);
            // Remove the module's entry from the config. Don't check schema when
            // uninstalling a module since we are only clearing a key.
            \Drupal::configFactory()->getEditable('core.extension')
                ->clear("module.{$module}")
                ->save(TRUE);
            // Update the module handler to remove the module.
            // The current ModuleHandler instance is obsolete with the kernel rebuild
            // below.
            $module_filenames = $this->moduleHandler
                ->getModuleList();
            unset($module_filenames[$module]);
            $this->moduleHandler
                ->setModuleList($module_filenames);
            // Remove any potential cache bins provided by the module.
            $this->removeCacheBins($module);
            // Clear the static cache of the "extension.list.module" service to pick
            // up the new module, since it merges the installation status of modules
            // into its statically cached list.
            \Drupal::service('extension.list.module')->reset();
            // Clear plugin manager caches.
            \Drupal::getContainer()->get('plugin.cache_clearer')
                ->clearCachedDefinitions();
            // Update the kernel to exclude the uninstalled modules.
            $this->updateKernel($module_filenames);
            // Update the theme registry to remove the newly uninstalled module.
            drupal_theme_rebuild();
            // Modules can alter theme info, so refresh theme data.
            // @todo ThemeHandler cannot be injected into ModuleHandler, since that
            //   causes a circular service dependency.
            // @see https://www.drupal.org/node/2208429
            \Drupal::service('theme_handler')->refreshInfo();
            \Drupal::logger('system')->info('%module module uninstalled.', [
                '%module' => $module,
            ]);
            $schema_store = \Drupal::keyValue('system.schema');
            $schema_store->delete($module);
            
            /** @var \Drupal\Core\Update\UpdateRegistry $post_update_registry */
            $post_update_registry = \Drupal::service('update.post_update_registry');
            $post_update_registry->filterOutInvokedUpdatesByModule($module);
        }
        // Rebuild routes after installing module. This is done here on top of
        // \Drupal\Core\Routing\RouteBuilder::destruct to not run into errors on
        // fastCGI which executes ::destruct() after the Module uninstallation page
        // was sent already.
        \Drupal::service('router.builder')->rebuild();
        drupal_get_installed_schema_version(NULL, TRUE);
        // Let other modules react.
        $this->moduleHandler
            ->invokeAll('modules_uninstalled', [
            $module_list,
            $sync_status,
        ]);
        // Flush all persistent caches.
        // Any cache entry might implicitly depend on the uninstalled modules,
        // so clear all of them explicitly.
        $this->moduleHandler
            ->invokeAll('cache_flush');
        foreach (Cache::getBins() as $service_id => $cache_backend) {
            $cache_backend->deleteAll();
        }
        return TRUE;
    }
    
    /**
     * Helper method for removing all cache bins registered by a given module.
     *
     * @param string $module
     *   The name of the module for which to remove all registered cache bins.
     */
    protected function removeCacheBins($module) {
        $service_yaml_file = drupal_get_path('module', $module) . "/{$module}.services.yml";
        if (!file_exists($service_yaml_file)) {
            return;
        }
        $definitions = Yaml::decode(file_get_contents($service_yaml_file));
        $cache_bin_services = array_filter(isset($definitions['services']) ? $definitions['services'] : [], function ($definition) {
            $tags = isset($definition['tags']) ? $definition['tags'] : [];
            foreach ($tags as $tag) {
                if (isset($tag['name']) && $tag['name'] == 'cache.bin') {
                    return TRUE;
                }
            }
            return FALSE;
        });
        foreach (array_keys($cache_bin_services) as $service_id) {
            $backend = $this->kernel
                ->getContainer()
                ->get($service_id);
            if ($backend instanceof CacheBackendInterface) {
                $backend->removeBin();
            }
        }
    }
    
    /**
     * Updates the kernel module list.
     *
     * @param string $module_filenames
     *   The list of installed modules.
     */
    protected function updateKernel($module_filenames) {
        // This reboots the kernel to register the module's bundle and its services
        // in the service container. The $module_filenames argument is taken over as
        // %container.modules% parameter, which is passed to a fresh ModuleHandler
        // instance upon first retrieval.
        $this->kernel
            ->updateModules($module_filenames, $module_filenames);
        // After rebuilding the container we need to update the injected
        // dependencies.
        $container = $this->kernel
            ->getContainer();
        $this->moduleHandler = $container->get('module_handler');
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateUninstall(array $module_list) {
        $reasons = [];
        foreach ($module_list as $module) {
            foreach ($this->uninstallValidators as $validator) {
                $validation_reasons = $validator->validate($module);
                if (!empty($validation_reasons)) {
                    if (!isset($reasons[$module])) {
                        $reasons[$module] = [];
                    }
                    $reasons[$module] = array_merge($reasons[$module], $validation_reasons);
                }
            }
        }
        return $reasons;
    }

}