text: import {RegistryBase} from './base';
  import {applyNamespaces, deepCopy, merge} from '../helpers/layouts';
  import * as layouts from '../layouts';
  
  /**
   * Helper for working with predefined layouts
   *
   * This is part of the public interface with LocusZoom and a major way that users interact to configure plots.
   *
   * Each layout object that is added or retrieved here is a deep copy and totally independent from any other object
   * @public
   * @extends module:registry/base:RegistryBase
   * @inheritDoc
   */
  class LayoutRegistry extends RegistryBase {
      // Implemented as a "registry of registries"- one lookup each for panels, plots, etc...
      get(type, name, overrides = {}) {
          if (!(type && name)) {
              throw new Error('Must specify both the type and name for the layout desired. See .list() for available options');
          }
          // This is a registry of registries. Fetching an item may apply additional custom behaviors, such as
          //  applying overrides or using namespaces to convert an abstract layout into a concrete one.
          let base = super.get(type).get(name);
          base = merge(overrides, base);
          if (base.unnamespaced) {
              delete base.unnamespaced;
              return deepCopy(base);
          }
          let default_namespace = '';
          if (typeof base.namespace == 'string') {
              default_namespace = base.namespace;
          } else if (typeof base.namespace == 'object' && Object.keys(base.namespace).length) {
              if (typeof base.namespace.default != 'undefined') {
                  default_namespace = base.namespace.default;
              } else {
                  default_namespace = base.namespace[Object.keys(base.namespace)[0]].toString();
              }
          }
          default_namespace += default_namespace.length ? ':' : '';
          const result = applyNamespaces(base, base.namespace, default_namespace);
  
          return deepCopy(result);
      }
  
      /**
       * Add a type of layout to the registry
       * @param {String} type The type of layout to add (plot, panel, data_layer, toolbar, toolbar_widgets, or tooltip)
       * @param {String} name The name of the layout object to add
       * @param {Object} item The layout object describing parameters
       * @param {boolean} override Whether to replace an existing item by that name
       * @return {*}
       */
      add(type, name, item, override = false) {
          if (!(type && name && item)) {
              throw new Error('To add a layout, type, name, and item must all be specified');
          }
          if (!(typeof item === 'object')) {
              throw new Error('The configuration to be added must be an object');
          }
  
          if (!this.has(type)) {
              super.add(type, new RegistryBase());
          }
          // Ensure that each use of a layout can be modified, by returning a copy is independent
          const copy = deepCopy(item);
          return super.get(type).add(name, copy, override);
      }
  
      /**
       * List all available types of layout (eg toolbar, panel, etc). If a specific type name is provided, list the
       *  layouts for that type of element ("just predefined panels").
       * @param {String} [type] The type of layout (eg toolbar, panel, etc)
       * @return {String[]|Object}
       */
      list(type) {
          if (!type) {
              let result = {};
              for (let [type, contents] of this._items) {
                  result[type] = contents.list();
              }
              return result;
          }
          return super.get(type).list();
      }
  
      /**
       * Static alias to a helper method. Preserved for backwards compatibility, so that UMD users can access this method.
       * @static
       * @private
       */
      merge(custom_layout, default_layout) {
          return merge(custom_layout, default_layout);
      }
  }
  
  /**
   * A plugin registry that allows plots to use both pre-defined and user-provided data adapters.
   * @alias module:LocusZoom~Layouts
   * @type {LayoutRegistry}
   */
  const registry = new LayoutRegistry();
  
  for (let [type, entries] of Object.entries(layouts)) {
      for (let [name, config] of Object.entries(entries)) {
          registry.add(type, name, config);
      }
  }
  
  
  export default registry;
  
  // Export base class for unit testing
  export {LayoutRegistry as _LayoutRegistry};
  