class NegotiationConfigureForm

class NegotiationConfigureForm extends ConfigFormBase {
    
    /**
     * Stores the configuration object for language.types.
     *
     * @var \Drupal\Core\Config\Config
     */
    protected $languageTypes;
    
    /**
     * The language manager.
     *
     * @var \Drupal\language\ConfigurableLanguageManagerInterface
     */
    protected $languageManager;
    
    /**
     * The language negotiator.
     *
     * @var \Drupal\language\LanguageNegotiatorInterface
     */
    protected $negotiator;
    
    /**
     * The block manager.
     *
     * @var \Drupal\Core\Block\BlockManagerInterface
     */
    protected $blockManager;
    
    /**
     * The block storage.
     *
     * @var \Drupal\Core\Entity\EntityStorageInterface|null
     */
    protected $blockStorage;
    
    /**
     * The theme handler.
     *
     * @var \Drupal\Core\Extension\ThemeHandlerInterface
     */
    protected $themeHandler;
    
    /**
     * Constructs a NegotiationConfigureForm object.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The factory for configuration objects.
     * @param \Drupal\language\ConfigurableLanguageManagerInterface $language_manager
     *   The language manager.
     * @param \Drupal\language\LanguageNegotiatorInterface $negotiator
     *   The language negotiation methods manager.
     * @param \Drupal\Core\Block\BlockManagerInterface $block_manager
     *   The block manager.
     * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
     *   The theme handler.
     * @param \Drupal\Core\Entity\EntityStorageInterface $block_storage
     *   The block storage, or NULL if not available.
     */
    public function __construct(ConfigFactoryInterface $config_factory, ConfigurableLanguageManagerInterface $language_manager, LanguageNegotiatorInterface $negotiator, BlockManagerInterface $block_manager, ThemeHandlerInterface $theme_handler, EntityStorageInterface $block_storage = NULL) {
        parent::__construct($config_factory);
        $this->languageTypes = $this->config('language.types');
        $this->languageManager = $language_manager;
        $this->negotiator = $negotiator;
        $this->blockManager = $block_manager;
        $this->themeHandler = $theme_handler;
        $this->blockStorage = $block_storage;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        $entity_type_manager = $container->get('entity_type.manager');
        $block_storage = $entity_type_manager->hasHandler('block', 'storage') ? $entity_type_manager->getStorage('block') : NULL;
        return new static($container->get('config.factory'), $container->get('language_manager'), $container->get('language_negotiator'), $container->get('plugin.manager.block'), $container->get('theme_handler'), $block_storage);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'language_negotiation_configure_form';
    }
    
    /**
     * {@inheritdoc}
     */
    protected function getEditableConfigNames() {
        return [
            'language.types',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $configurable = $this->languageTypes
            ->get('configurable');
        $form = [
            '#theme' => 'language_negotiation_configure_form',
            '#language_types_info' => $this->languageManager
                ->getDefinedLanguageTypesInfo(),
            '#language_negotiation_info' => $this->negotiator
                ->getNegotiationMethods(),
        ];
        $form['#language_types'] = [];
        foreach ($form['#language_types_info'] as $type => $info) {
            // Show locked language types only if they are configurable.
            if (empty($info['locked']) || in_array($type, $configurable)) {
                $form['#language_types'][] = $type;
            }
        }
        foreach ($form['#language_types'] as $type) {
            $this->configureFormTable($form, $type);
        }
        $form['actions'] = [
            '#type' => 'actions',
        ];
        $form['actions']['submit'] = [
            '#type' => 'submit',
            '#button_type' => 'primary',
            '#value' => $this->t('Save settings'),
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $configurable_types = $form['#language_types'];
        $stored_values = $this->languageTypes
            ->get('configurable');
        $customized = [];
        $method_weights_type = [];
        foreach ($configurable_types as $type) {
            $customized[$type] = in_array($type, $stored_values);
            $method_weights = [];
            $enabled_methods = $form_state->getValue([
                $type,
                'enabled',
            ]);
            $enabled_methods[LanguageNegotiationSelected::METHOD_ID] = TRUE;
            $method_weights_input = $form_state->getValue([
                $type,
                'weight',
            ]);
            if ($form_state->hasValue([
                $type,
                'configurable',
            ])) {
                $customized[$type] = !$form_state->isValueEmpty([
                    $type,
                    'configurable',
                ]);
            }
            foreach ($method_weights_input as $method_id => $weight) {
                if ($enabled_methods[$method_id]) {
                    $method_weights[$method_id] = $weight;
                }
            }
            $method_weights_type[$type] = $method_weights;
            $this->languageTypes
                ->set('negotiation.' . $type . '.method_weights', $method_weights_input)
                ->save();
        }
        // Update non-configurable language types and the related language
        // negotiation configuration.
        $this->negotiator
            ->updateConfiguration(array_keys(array_filter($customized)));
        // Update the language negotiations after setting the configurability.
        foreach ($method_weights_type as $type => $method_weights) {
            $this->negotiator
                ->saveConfiguration($type, $method_weights);
        }
        // Clear block definitions cache since the available blocks and their names
        // may have been changed based on the configurable types.
        if ($this->blockStorage) {
            // If there is an active language switcher for a language type that has
            // been made not configurable, deactivate it first.
            $non_configurable = array_keys(array_diff($customized, array_filter($customized)));
            $this->disableLanguageSwitcher($non_configurable);
        }
        $this->blockManager
            ->clearCachedDefinitions();
        $form_state->setRedirect('language.negotiation');
        $this->messenger()
            ->addStatus($this->t('Language detection configuration saved.'));
    }
    
    /**
     * Builds a language negotiation method configuration table.
     *
     * @param array $form
     *   The language negotiation configuration form.
     * @param string $type
     *   The language type to generate the table for.
     */
    protected function configureFormTable(array &$form, $type) {
        $info = $form['#language_types_info'][$type];
        $table_form = [
            '#title' => $this->t('@type language detection', [
                '@type' => $info['name'],
            ]),
            '#tree' => TRUE,
            '#description' => $info['description'],
            '#language_negotiation_info' => [],
            '#show_operations' => FALSE,
            'weight' => [
                '#tree' => TRUE,
            ],
        ];
        // Only show configurability checkbox for the unlocked language types.
        if (empty($info['locked'])) {
            $configurable = $this->languageTypes
                ->get('configurable');
            $table_form['configurable'] = [
                '#type' => 'checkbox',
                '#title' => $this->t('Customize %language_name language detection to differ from Interface text language detection settings', [
                    '%language_name' => $info['name'],
                ]),
                '#default_value' => in_array($type, $configurable),
                '#attributes' => [
                    'class' => [
                        'language-customization-checkbox',
                    ],
                ],
                '#attached' => [
                    'library' => [
                        'language/drupal.language.admin',
                    ],
                ],
            ];
        }
        $negotiation_info = $form['#language_negotiation_info'];
        $enabled_methods = $this->languageTypes
            ->get('negotiation.' . $type . '.enabled') ?: [];
        $methods_weight = $this->languageTypes
            ->get('negotiation.' . $type . '.method_weights') ?: [];
        // Add missing data to the methods lists.
        foreach ($negotiation_info as $method_id => $method) {
            if (!isset($methods_weight[$method_id])) {
                $methods_weight[$method_id] = $method['weight'] ?? 0;
            }
        }
        // Order methods list by weight.
        asort($methods_weight);
        foreach ($methods_weight as $method_id => $weight) {
            // A language method might be no more available if the defining module has
            // been disabled after the last configuration saving.
            if (!isset($negotiation_info[$method_id])) {
                continue;
            }
            $enabled = isset($enabled_methods[$method_id]);
            $method = $negotiation_info[$method_id];
            // List the method only if the current type is defined in its 'types' key.
            // If it is not defined default to all the configurable language types.
            $types = array_flip($method['types'] ?? $form['#language_types']);
            if (isset($types[$type])) {
                $table_form['#language_negotiation_info'][$method_id] = $method;
                $method_name = $method['name'];
                $table_form['weight'][$method_id] = [
                    '#type' => 'weight',
                    '#title' => $this->t('Weight for @title language detection method', [
                        '@title' => mb_strtolower($method_name),
                    ]),
                    '#title_display' => 'invisible',
                    '#default_value' => $weight,
                    '#attributes' => [
                        'class' => [
                            "language-method-weight-{$type}",
                        ],
                    ],
                    '#delta' => 20,
                ];
                $table_form['title'][$method_id] = [
                    '#plain_text' => $method_name,
                ];
                $table_form['enabled'][$method_id] = [
                    '#type' => 'checkbox',
                    '#title' => $this->t('Enable @title language detection method', [
                        '@title' => mb_strtolower($method_name),
                    ]),
                    '#title_display' => 'invisible',
                    '#default_value' => $enabled,
                ];
                if ($method_id === LanguageNegotiationSelected::METHOD_ID) {
                    $table_form['enabled'][$method_id]['#default_value'] = TRUE;
                    $table_form['enabled'][$method_id]['#attributes'] = [
                        'disabled' => 'disabled',
                    ];
                }
                $table_form['description'][$method_id] = [
                    '#markup' => $method['description'],
                ];
                $config_op = [];
                if (isset($method['config_route_name'])) {
                    $config_op['configure'] = [
                        'title' => $this->t('Configure'),
                        'url' => Url::fromRoute($method['config_route_name']),
                    ];
                    // If there is at least one operation enabled show the operation
                    // column.
                    $table_form['#show_operations'] = TRUE;
                }
                $table_form['operation'][$method_id] = [
                    '#type' => 'operations',
                    '#links' => $config_op,
                ];
            }
        }
        $form[$type] = $table_form;
    }
    
    /**
     * Disables the language switcher blocks.
     *
     * @param array $language_types
     *   An array containing all language types whose language switchers need to
     *   be disabled.
     */
    protected function disableLanguageSwitcher(array $language_types) {
        $theme = $this->themeHandler
            ->getDefault();
        $blocks = $this->blockStorage
            ->loadByProperties([
            'theme' => $theme,
        ]);
        foreach ($language_types as $language_type) {
            foreach ($blocks as $block) {
                if ($block->getPluginId() == 'language_block:' . $language_type) {
                    $block->delete();
                }
            }
        }
    }

}