class Config

class Config extends StorableConfigBase {
    
    /**
     * An event dispatcher instance to use for configuration events.
     *
     * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
     */
    protected $eventDispatcher;
    
    /**
     * The current runtime data.
     *
     * The configuration data from storage merged with module and settings
     * overrides.
     *
     * @var array
     */
    protected $overriddenData;
    
    /**
     * The current module overrides.
     *
     * @var array
     */
    protected $moduleOverrides;
    
    /**
     * The current settings overrides.
     *
     * @var array
     */
    protected $settingsOverrides;
    
    /**
     * Constructs a configuration object.
     *
     * @param string $name
     *   The name of the configuration object being constructed.
     * @param \Drupal\Core\Config\StorageInterface $storage
     *   A storage object to use for reading and writing the
     *   configuration data.
     * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
     *   An event dispatcher instance to use for configuration events.
     * @param \Drupal\Core\Config\TypedConfigManagerInterface $typed_config
     *   The typed configuration manager service.
     */
    public function __construct($name, StorageInterface $storage, EventDispatcherInterface $event_dispatcher, TypedConfigManagerInterface $typed_config) {
        $this->name = $name;
        $this->storage = $storage;
        $this->eventDispatcher = $event_dispatcher;
        $this->typedConfigManager = $typed_config;
    }
    
    /**
     * {@inheritdoc}
     */
    public function initWithData(array $data) {
        parent::initWithData($data);
        $this->resetOverriddenData();
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function get($key = '') {
        if (!isset($this->overriddenData)) {
            $this->setOverriddenData();
        }
        if (empty($key)) {
            return $this->overriddenData;
        }
        else {
            $parts = explode('.', $key);
            if (count($parts) == 1) {
                return isset($this->overriddenData[$key]) ? $this->overriddenData[$key] : NULL;
            }
            else {
                $value = NestedArray::getValue($this->overriddenData, $parts, $key_exists);
                return $key_exists ? $value : NULL;
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function setData(array $data) {
        parent::setData($data);
        $this->resetOverriddenData();
        return $this;
    }
    
    /**
     * Sets settings.php overrides for this configuration object.
     *
     * The overridden data only applies to this configuration object.
     *
     * @param array $data
     *   The overridden values of the configuration data.
     *
     * @return $this
     *   The configuration object.
     */
    public function setSettingsOverride(array $data) {
        $this->settingsOverrides = $data;
        $this->resetOverriddenData();
        return $this;
    }
    
    /**
     * Sets module overrides for this configuration object.
     *
     * @param array $data
     *   The overridden values of the configuration data.
     *
     * @return $this
     *   The configuration object.
     */
    public function setModuleOverride(array $data) {
        $this->moduleOverrides = $data;
        $this->resetOverriddenData();
        return $this;
    }
    
    /**
     * Sets the current data for this configuration object.
     *
     * Configuration overrides operate at two distinct layers: modules and
     * settings.php. Overrides in settings.php take precedence over values
     * provided by modules. Precedence or different module overrides is
     * determined by the priority of the config.factory.override tagged services.
     *
     * @return $this
     *   The configuration object.
     */
    protected function setOverriddenData() {
        $this->overriddenData = $this->data;
        if (isset($this->moduleOverrides) && is_array($this->moduleOverrides)) {
            $this->overriddenData = NestedArray::mergeDeepArray([
                $this->overriddenData,
                $this->moduleOverrides,
            ], TRUE);
        }
        if (isset($this->settingsOverrides) && is_array($this->settingsOverrides)) {
            $this->overriddenData = NestedArray::mergeDeepArray([
                $this->overriddenData,
                $this->settingsOverrides,
            ], TRUE);
        }
        return $this;
    }
    
    /**
     * Resets the current data, so overrides are re-applied.
     *
     * This method should be called after the original data or the overridden data
     * has been changed.
     *
     * @return $this
     *   The configuration object.
     */
    protected function resetOverriddenData() {
        unset($this->overriddenData);
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function set($key, $value) {
        parent::set($key, $value);
        $this->resetOverriddenData();
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function clear($key) {
        parent::clear($key);
        $this->resetOverriddenData();
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function save($has_trusted_data = FALSE) {
        // Validate the configuration object name before saving.
        static::validateName($this->name);
        // If there is a schema for this configuration object, cast all values to
        // conform to the schema.
        if (!$has_trusted_data) {
            if ($this->typedConfigManager
                ->hasConfigSchema($this->name)) {
                // Ensure that the schema wrapper has the latest data.
                $this->schemaWrapper = NULL;
                foreach ($this->data as $key => $value) {
                    $this->data[$key] = $this->castValue($key, $value);
                }
            }
            else {
                foreach ($this->data as $key => $value) {
                    $this->validateValue($key, $value);
                }
            }
        }
        // Potentially configuration schema could have changed the underlying data's
        // types.
        $this->resetOverriddenData();
        $this->storage
            ->write($this->name, $this->data);
        if (!$this->isNew) {
            Cache::invalidateTags($this->getCacheTags());
        }
        $this->isNew = FALSE;
        $this->eventDispatcher
            ->dispatch(ConfigEvents::SAVE, new ConfigCrudEvent($this));
        $this->originalData = $this->data;
        return $this;
    }
    
    /**
     * Deletes the configuration object.
     *
     * @return $this
     *   The configuration object.
     */
    public function delete() {
        $this->data = [];
        $this->storage
            ->delete($this->name);
        Cache::invalidateTags($this->getCacheTags());
        $this->isNew = TRUE;
        $this->resetOverriddenData();
        $this->eventDispatcher
            ->dispatch(ConfigEvents::DELETE, new ConfigCrudEvent($this));
        $this->originalData = $this->data;
        return $this;
    }
    
    /**
     * Gets the raw data without overrides.
     *
     * @return array
     *   The raw data.
     */
    public function getRawData() {
        return $this->data;
    }
    
    /**
     * Gets original data from this configuration object.
     *
     * Original data is the data as it is immediately after loading from
     * configuration storage before any changes. If this is a new configuration
     * object it will be an empty array.
     *
     * @see \Drupal\Core\Config\Config::get()
     *
     * @param string $key
     *   A string that maps to a key within the configuration data.
     * @param bool $apply_overrides
     *   Apply any overrides to the original data. Defaults to TRUE.
     *
     * @return mixed
     *   The data that was requested.
     */
    public function getOriginal($key = '', $apply_overrides = TRUE) {
        $original_data = $this->originalData;
        if ($apply_overrides) {
            // Apply overrides.
            if (isset($this->moduleOverrides) && is_array($this->moduleOverrides)) {
                $original_data = NestedArray::mergeDeepArray([
                    $original_data,
                    $this->moduleOverrides,
                ], TRUE);
            }
            if (isset($this->settingsOverrides) && is_array($this->settingsOverrides)) {
                $original_data = NestedArray::mergeDeepArray([
                    $original_data,
                    $this->settingsOverrides,
                ], TRUE);
            }
        }
        if (empty($key)) {
            return $original_data;
        }
        else {
            $parts = explode('.', $key);
            if (count($parts) == 1) {
                return isset($original_data[$key]) ? $original_data[$key] : NULL;
            }
            else {
                $value = NestedArray::getValue($original_data, $parts, $key_exists);
                return $key_exists ? $value : NULL;
            }
        }
    }
    
    /**
     * Determines if overrides are applied to a key for this configuration object.
     *
     * @param string $key
     *   (optional) A string that maps to a key within the configuration data.
     *   For instance in the following configuration array:
     *   @code
     *   array(
     *     'foo' => array(
     *       'bar' => 'baz',
     *     ),
     *   );
     *   @endcode
     *   A key of 'foo.bar' would map to the string 'baz'. However, a key of 'foo'
     *   would map to the array('bar' => 'baz').
     *   If not supplied TRUE will be returned if there are any overrides at all
     *   for this configuration object.
     *
     * @return bool
     *   TRUE if there are any overrides for the key, otherwise FALSE.
     */
    public function hasOverrides($key = '') {
        if (empty($key)) {
            return !(empty($this->moduleOverrides) && empty($this->settingsOverrides));
        }
        else {
            $parts = explode('.', $key);
            $override_exists = FALSE;
            if (isset($this->moduleOverrides) && is_array($this->moduleOverrides)) {
                $override_exists = NestedArray::keyExists($this->moduleOverrides, $parts);
            }
            if (!$override_exists && isset($this->settingsOverrides) && is_array($this->settingsOverrides)) {
                $override_exists = NestedArray::keyExists($this->settingsOverrides, $parts);
            }
            return $override_exists;
        }
    }

}