class LocaleConfigManager

class LocaleConfigManager {
    
    /**
     * The storage instance for reading configuration data.
     *
     * @var \Drupal\Core\Config\StorageInterface
     */
    protected $configStorage;
    
    /**
     * The string storage for reading and writing translations.
     *
     * @var \Drupal\locale\StringStorageInterface
     */
    protected $localeStorage;
    
    /**
     * Array with preloaded string translations.
     *
     * @var array
     */
    protected $translations;
    
    /**
     * The configuration factory.
     *
     * @var \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected $configFactory;
    
    /**
     * The language manager.
     *
     * @var \Drupal\language\ConfigurableLanguageManagerInterface
     */
    protected $languageManager;
    
    /**
     * The typed config manager.
     *
     * @var \Drupal\Core\Config\TypedConfigManagerInterface
     */
    protected $typedConfigManager;
    
    /**
     * Whether or not configuration translations are being updated from locale.
     *
     * @see self::isUpdatingFromLocale()
     *
     * @var bool
     */
    protected $isUpdatingFromLocale = FALSE;
    
    /**
     * The locale default config storage instance.
     *
     * @var \Drupal\locale\LocaleDefaultConfigStorage
     */
    protected $defaultConfigStorage;
    
    /**
     * The configuration manager.
     *
     * @var \Drupal\Core\Config\ConfigManagerInterface
     */
    protected $configManager;
    
    /**
     * Creates a new typed configuration manager.
     *
     * @param \Drupal\Core\Config\StorageInterface $config_storage
     *   The storage object to use for reading configuration data.
     * @param \Drupal\locale\StringStorageInterface $locale_storage
     *   The locale storage to use for reading string translations.
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The configuration factory
     * @param \Drupal\Core\Config\TypedConfigManagerInterface $typed_config
     *   The typed configuration manager.
     * @param \Drupal\language\ConfigurableLanguageManagerInterface $language_manager
     *   The language manager.
     * @param \Drupal\locale\LocaleDefaultConfigStorage $default_config_storage
     *   The locale default configuration storage.
     * @param \Drupal\Core\Config\ConfigManagerInterface $config_manager
     *   The configuration manager.
     */
    public function __construct(StorageInterface $config_storage, StringStorageInterface $locale_storage, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config, ConfigurableLanguageManagerInterface $language_manager, LocaleDefaultConfigStorage $default_config_storage, ConfigManagerInterface $config_manager) {
        $this->configStorage = $config_storage;
        $this->localeStorage = $locale_storage;
        $this->configFactory = $config_factory;
        $this->typedConfigManager = $typed_config;
        $this->languageManager = $language_manager;
        $this->defaultConfigStorage = $default_config_storage;
        $this->configManager = $config_manager;
    }
    
    /**
     * Gets array of translated strings for Locale translatable configuration.
     *
     * @param string $name
     *   Configuration object name.
     *
     * @return array
     *   Array of Locale translatable elements of the default configuration in
     *   $name.
     */
    public function getTranslatableDefaultConfig($name) {
        if ($this->isSupported($name)) {
            // Create typed configuration wrapper based on install storage data.
            $data = $this->defaultConfigStorage
                ->read($name);
            $typed_config = $this->typedConfigManager
                ->createFromNameAndData($name, $data);
            if ($typed_config instanceof TraversableTypedDataInterface) {
                return $this->getTranslatableData($typed_config);
            }
        }
        return [];
    }
    
    /**
     * Gets translatable configuration data for a typed configuration element.
     *
     * @param \Drupal\Core\TypedData\TypedDataInterface $element
     *   Typed configuration element.
     *
     * @return array|\Drupal\Core\StringTranslation\TranslatableMarkup
     *   A nested array matching the exact structure under $element with only the
     *   elements that are translatable wrapped into a TranslatableMarkup. If the
     *   provided $element is not traversable, the return value is a single
     *   TranslatableMarkup.
     */
    protected function getTranslatableData(TypedDataInterface $element) {
        $translatable = [];
        if ($element instanceof TraversableTypedDataInterface) {
            foreach ($element as $key => $property) {
                $value = $this->getTranslatableData($property);
                if (!empty($value)) {
                    $translatable[$key] = $value;
                }
            }
        }
        else {
            // Something is only translatable by Locale if there is a string in the
            // first place.
            $value = $element->getValue();
            $definition = $element->getDataDefinition();
            if (!empty($definition['translatable']) && $value !== '' && $value !== NULL) {
                $options = [];
                if (isset($definition['translation context'])) {
                    $options['context'] = $definition['translation context'];
                }
                return new TranslatableMarkup($value, [], $options);
            }
        }
        return $translatable;
    }
    
    /**
     * Process the translatable data array with a given language.
     *
     * If the given language is translatable, will return the translated copy
     * which will only contain strings that had translations. If the given
     * language is English and is not translatable, will return a simplified
     * array of the English source strings only.
     *
     * @param string $name
     *   The configuration name.
     * @param array $active
     *   The active configuration data.
     * @param array|\Drupal\Core\StringTranslation\TranslatableMarkup[] $translatable
     *   The translatable array structure. A nested array matching the exact
     *   structure under of the default configuration for $name with only the
     *   elements that are translatable wrapped into a TranslatableMarkup.
     * @param string $langcode
     *   The language code to process the array with.
     *
     * @return array
     *   Processed translatable data array. Will only contain translations
     *   different from source strings or in case of untranslatable English, the
     *   source strings themselves.
     *
     * @see self::getTranslatableData()
     */
    protected function processTranslatableData($name, array $active, array $translatable, $langcode) {
        $translated = [];
        foreach ($translatable as $key => $item) {
            if (!isset($active[$key])) {
                continue;
            }
            if (is_array($item)) {
                // Only add this key if there was a translated value underneath.
                $value = $this->processTranslatableData($name, $active[$key], $item, $langcode);
                if (!empty($value)) {
                    $translated[$key] = $value;
                }
            }
            else {
                if (locale_is_translatable($langcode)) {
                    $value = $this->translateString($name, $langcode, $item->getUntranslatedString(), $item->getOption('context'));
                }
                else {
                    $value = $item->getUntranslatedString();
                }
                if (!empty($value)) {
                    $translated[$key] = $value;
                }
            }
        }
        return $translated;
    }
    
    /**
     * Saves translated configuration override.
     *
     * @param string $name
     *   Configuration object name.
     * @param string $langcode
     *   Language code.
     * @param array $data
     *   Configuration data to be saved, that will be only the translated values.
     */
    protected function saveTranslationOverride($name, $langcode, array $data) {
        $this->isUpdatingFromLocale = TRUE;
        $this->languageManager
            ->getLanguageConfigOverride($langcode, $name)
            ->setData($data)
            ->save();
        $this->isUpdatingFromLocale = FALSE;
    }
    
    /**
     * Saves translated configuration data.
     *
     * @param string $name
     *   Configuration object name.
     * @param array $data
     *   Configuration data to be saved with translations merged in.
     */
    protected function saveTranslationActive($name, array $data) {
        $this->isUpdatingFromLocale = TRUE;
        $this->configFactory
            ->getEditable($name)
            ->setData($data)
            ->save();
        $this->isUpdatingFromLocale = FALSE;
    }
    
    /**
     * Deletes translated configuration data.
     *
     * @param string $name
     *   Configuration object name.
     * @param string $langcode
     *   Language code.
     */
    protected function deleteTranslationOverride($name, $langcode) {
        $this->isUpdatingFromLocale = TRUE;
        $this->languageManager
            ->getLanguageConfigOverride($langcode, $name)
            ->delete();
        $this->isUpdatingFromLocale = FALSE;
    }
    
    /**
     * Gets configuration names associated with components.
     *
     * @param array $components
     *   (optional) Array of component lists indexed by type. If not present or it
     *   is an empty array, it will update all components.
     *
     * @return array
     *   Array of configuration object names.
     */
    public function getComponentNames(array $components = []) {
        $components = array_filter($components);
        if ($components) {
            $names = [];
            foreach ($components as $type => $list) {
                // InstallStorage::getComponentNames returns a list of folders keyed by
                // config name.
                $names = array_merge($names, $this->defaultConfigStorage
                    ->getComponentNames($type, $list));
            }
            return $names;
        }
        else {
            return $this->defaultConfigStorage
                ->listAll();
        }
    }
    
    /**
     * Gets configuration names associated with strings.
     *
     * @param array $lids
     *   Array with string identifiers.
     *
     * @return array
     *   Array of configuration object names.
     */
    public function getStringNames(array $lids) {
        $names = [];
        $locations = $this->localeStorage
            ->getLocations([
            'sid' => $lids,
            'type' => 'configuration',
        ]);
        foreach ($locations as $location) {
            $names[$location->name] = $location->name;
        }
        return $names;
    }
    
    /**
     * Deletes configuration for language.
     *
     * @param string $langcode
     *   Language code to delete.
     */
    public function deleteLanguageTranslations($langcode) {
        $this->isUpdatingFromLocale = TRUE;
        $storage = $this->languageManager
            ->getLanguageConfigOverrideStorage($langcode);
        foreach ($storage->listAll() as $name) {
            $this->languageManager
                ->getLanguageConfigOverride($langcode, $name)
                ->delete();
        }
        $this->isUpdatingFromLocale = FALSE;
    }
    
    /**
     * Translates string using the localization system.
     *
     * So far we only know how to translate strings from English so the source
     * string should be in English.
     * Unlike regular t() translations, strings will be added to the source
     * tables only if this is marked as default data.
     *
     * @param string $name
     *   Name of the configuration location.
     * @param string $langcode
     *   Language code to translate to.
     * @param string $source
     *   The source string, should be English.
     * @param string $context
     *   The string context.
     *
     * @return string|false
     *   Translated string if there is a translation, FALSE if not.
     */
    public function translateString($name, $langcode, $source, $context) {
        if ($source) {
            // If translations for a language have not been loaded yet.
            if (!isset($this->translations[$name][$langcode])) {
                // Preload all translations for this configuration name and language.
                $this->translations[$name][$langcode] = [];
                foreach ($this->localeStorage
                    ->getTranslations([
                    'language' => $langcode,
                    'type' => 'configuration',
                    'name' => $name,
                ]) as $string) {
                    $this->translations[$name][$langcode][$string->context][$string->source] = $string;
                }
            }
            if (!isset($this->translations[$name][$langcode][$context][$source])) {
                // There is no translation of the source string in this config location
                // to this language for this context.
                if ($translation = $this->localeStorage
                    ->findTranslation([
                    'source' => $source,
                    'context' => $context,
                    'language' => $langcode,
                ])) {
                    // Look for a translation of the string. It might have one, but not
                    // be saved in this configuration location yet.
                    // If the string has a translation for this context to this language,
                    // save it in the configuration location so it can be looked up faster
                    // next time.
                    $this->localeStorage
                        ->createString((array) $translation)
                        ->addLocation('configuration', $name)
                        ->save();
                }
                else {
                    // No translation was found. Add the source to the configuration
                    // location so it can be translated, and the string is faster to look
                    // for next time.
                    $translation = $this->localeStorage
                        ->createString([
                        'source' => $source,
                        'context' => $context,
                    ])
                        ->addLocation('configuration', $name)
                        ->save();
                }
                // Add an entry, either the translation found, or a blank string object
                // to track the source string, to this configuration location, language,
                // and context.
                $this->translations[$name][$langcode][$context][$source] = $translation;
            }
            // Return the string only when the string object had a translation.
            if ($this->translations[$name][$langcode][$context][$source]
                ->isTranslation()) {
                return $this->translations[$name][$langcode][$context][$source]
                    ->getString();
            }
        }
        return FALSE;
    }
    
    /**
     * Reset static cache of configuration string translations.
     *
     * @return $this
     */
    public function reset() {
        $this->translations = [];
        return $this;
    }
    
    /**
     * Get the translation object for the given source/context and language.
     *
     * @param string $name
     *   Name of the configuration location.
     * @param string $langcode
     *   Language code to translate to.
     * @param string $source
     *   The source string, should be English.
     * @param string $context
     *   The string context.
     *
     * @return \Drupal\locale\TranslationString|false
     *   The translation object if the string was not empty or FALSE otherwise.
     */
    public function getStringTranslation($name, $langcode, $source, $context) {
        if ($source) {
            $this->translateString($name, $langcode, $source, $context);
            if ($string = $this->translations[$name][$langcode][$context][$source]) {
                if (!$string->isTranslation()) {
                    $conditions = [
                        'lid' => $string->lid,
                        'language' => $langcode,
                    ];
                    $translation = $this->localeStorage
                        ->createTranslation($conditions);
                    $this->translations[$name][$langcode][$context][$source] = $translation;
                    return $translation;
                }
                else {
                    return $string;
                }
            }
        }
        return FALSE;
    }
    
    /**
     * Checks whether a language has configuration translation.
     *
     * @param string $name
     *   Configuration name.
     * @param string $langcode
     *   A language code.
     *
     * @return bool
     *   A boolean indicating if a language has configuration translations.
     */
    public function hasTranslation($name, $langcode) {
        $translation = $this->languageManager
            ->getLanguageConfigOverride($langcode, $name);
        return !$translation->isNew();
    }
    
    /**
     * Returns the original language code for this shipped configuration.
     *
     * @param string $name
     *   The configuration name.
     *
     * @return null|string
     *   Language code of the default configuration for $name. If the default
     *   configuration data for $name did not contain a language code, it is
     *   assumed to be English. The return value is NULL if no such default
     *   configuration exists.
     */
    public function getDefaultConfigLangcode($name) {
        // Config entities that do not have the 'default_config_hash' cannot be
        // shipped configuration regardless of whether there is a name match.
        // configurable_language entities are a special case since they can be
        // translated regardless of whether they are shipped if they in the standard
        // language list.
        $config_entity_type = $this->configManager
            ->getEntityTypeIdByName($name);
        if (!$config_entity_type || $config_entity_type === 'configurable_language' || !empty($this->configFactory
            ->get($name)
            ->get('_core.default_config_hash'))) {
            $shipped = $this->defaultConfigStorage
                ->read($name);
            if (!empty($shipped)) {
                return !empty($shipped['langcode']) ? $shipped['langcode'] : 'en';
            }
        }
        return NULL;
    }
    
    /**
     * Returns the current language code for this active configuration.
     *
     * @param string $name
     *   The configuration name.
     *
     * @return null|string
     *   Language code of the current active configuration for $name. If the
     *   configuration data for $name did not contain a language code, it is
     *   assumed to be English. The return value is NULL if no such active
     *   configuration exists.
     */
    public function getActiveConfigLangcode($name) {
        $active = $this->configStorage
            ->read($name);
        if (!empty($active)) {
            return !empty($active['langcode']) ? $active['langcode'] : 'en';
        }
    }
    
    /**
     * Whether the given configuration is supported for interface translation.
     *
     * @param string $name
     *   The configuration name.
     *
     * @return bool
     *   TRUE if interface translation is supported.
     */
    public function isSupported($name) {
        return $this->getDefaultConfigLangcode($name) == 'en' && $this->configStorage
            ->read($name);
    }
    
    /**
     * Indicates whether configuration translations are being updated from locale.
     *
     * @return bool
     *   Whether or not configuration translations are currently being updated.
     *   If TRUE, LocaleConfigManager is in control of the process and the
     *   reference data is locale's storage. Changes made to active configuration
     *   and overrides in this case should not feed back to locale storage.
     *   On the other hand, when not updating from locale and configuration
     *   translations change, we need to feed back to the locale storage.
     */
    public function isUpdatingTranslationsFromLocale() {
        return $this->isUpdatingFromLocale;
    }
    
    /**
     * Updates all configuration translations for the names / languages provided.
     *
     * To be used when interface translation changes result in the need to update
     * configuration translations to keep them in sync.
     *
     * @param array $names
     *   Array of names of configuration objects to update.
     * @param array $langcodes
     *   (optional) Array of language codes to update. Defaults to all
     *   configurable languages.
     *
     * @return int
     *   Total number of configuration override and active configuration objects
     *   updated (saved or removed).
     */
    public function updateConfigTranslations(array $names, array $langcodes = []) {
        $langcodes = $langcodes ? $langcodes : array_keys($this->languageManager
            ->getLanguages());
        $count = 0;
        foreach ($names as $name) {
            $translatable = $this->getTranslatableDefaultConfig($name);
            if (empty($translatable)) {
                // If there is nothing translatable in this configuration or not
                // supported, skip it.
                continue;
            }
            $active_langcode = $this->getActiveConfigLangcode($name);
            $active = $this->configStorage
                ->read($name);
            foreach ($langcodes as $langcode) {
                $processed = $this->processTranslatableData($name, $active, $translatable, $langcode);
                // If the language code is not the same as the active storage
                // language, we should update the configuration override.
                if ($langcode != $active_langcode) {
                    $override = $this->languageManager
                        ->getLanguageConfigOverride($langcode, $name);
                    // Filter out locale managed configuration keys so that translations
                    // removed from Locale will be reflected in the config override.
                    $data = $this->filterOverride($override->get(), $translatable);
                    if (!empty($processed)) {
                        // Merge in the Locale managed translations with existing data.
                        $data = NestedArray::mergeDeepArray([
                            $data,
                            $processed,
                        ], TRUE);
                    }
                    if (empty($data) && !$override->isNew()) {
                        // The configuration override contains Locale overrides that no
                        // longer exist.
                        $this->deleteTranslationOverride($name, $langcode);
                        $count++;
                    }
                    elseif (!empty($data)) {
                        // Update translation data in configuration override.
                        $this->saveTranslationOverride($name, $langcode, $data);
                        $count++;
                    }
                }
                elseif (locale_is_translatable($langcode)) {
                    // If the language code is the active storage language, we should
                    // update. If it is English, we should only update if English is also
                    // translatable.
                    $active = NestedArray::mergeDeepArray([
                        $active,
                        $processed,
                    ], TRUE);
                    $this->saveTranslationActive($name, $active);
                    $count++;
                }
            }
        }
        return $count;
    }
    
    /**
     * Filters override data based on default translatable items.
     *
     * @param array $override_data
     *   Configuration override data.
     * @param array $translatable
     *   Translatable data array. @see self::getTranslatableData()
     *
     * @return array
     *   Nested array of any items of $override_data which did not have keys in
     *   $translatable. May be empty if $override_data only had items which were
     *   also in $translatable.
     */
    protected function filterOverride(array $override_data, array $translatable) {
        $filtered_data = [];
        foreach ($override_data as $key => $value) {
            if (isset($translatable[$key])) {
                // If the translatable default configuration has this key, look further
                // for subkeys or ignore this element for scalar values.
                if (is_array($value)) {
                    $value = $this->filterOverride($value, $translatable[$key]);
                    if (!empty($value)) {
                        $filtered_data[$key] = $value;
                    }
                }
            }
            else {
                // If this key was not in the translatable default configuration,
                // keep it.
                $filtered_data[$key] = $value;
            }
        }
        return $filtered_data;
    }
    
    /**
     * Updates default configuration when new modules or themes are installed.
     */
    public function updateDefaultConfigLangcodes() {
        $this->isUpdatingFromLocale = TRUE;
        // Need to rewrite some default configuration language codes if the default
        // site language is not English.
        $default_langcode = $this->languageManager
            ->getDefaultLanguage()
            ->getId();
        if ($default_langcode != 'en') {
            // Update active configuration copies of all prior shipped configuration if
            // they are still English. It is not enough to change configuration shipped
            // with the components just installed, because installing a component such
            // as views may bring in default configuration from prior components.
            $names = $this->getComponentNames();
            foreach ($names as $name) {
                $config = $this->configFactory
                    ->reset($name)
                    ->getEditable($name);
                // Should only update if still exists in active configuration. If locale
                // module is enabled later, then some configuration may not exist anymore.
                if (!$config->isNew()) {
                    $typed_config = $this->typedConfigManager
                        ->createFromNameAndData($config->getName(), $config->getRawData());
                    $langcode = $config->get('langcode');
                    // Only set a `langcode` if this config actually contains translatable
                    // data.
                    // @see \Drupal\Core\Config\Plugin\Validation\Constraint\LangcodeRequiredIfTranslatableValuesConstraint
                    if (!empty($this->getTranslatableData($typed_config)) && (empty($langcode) || $langcode == 'en')) {
                        $config->set('langcode', $default_langcode)
                            ->save();
                    }
                }
            }
        }
        $this->isUpdatingFromLocale = FALSE;
    }

}