/**
 * @author Martin Karkowski
 * @email m.karkowski@zema.de
 */

import { getSingleton } from "../helpers/singletonMethod";
import {
  IDispatcherConstructor,
  INopeDispatcherOptions,
  INopePackageLoader,
  INopePackageLoaderConstructor,
} from "../types/nope";
import { generateNopeBasicPackage } from "./generateNopeBasicPackage";
import { NopePackageLoader } from "./nopePackageLoader";

/**
 * Function to extract the Package-Loader.
 * @param {INopeDispatcherOptions} dispatcherOptions The provided options for the Dispatcher
 * @param options Settings for the creation of the Dispatcher etc.
 * @returns {INopePackageLoader} The Package loader.
 */
export function getPackageLoader(
  dispatcherOptions: INopeDispatcherOptions,
  options: {
    packageLoaderConstructorClass?: INopePackageLoaderConstructor;
    dispatcherConstructorClass?: IDispatcherConstructor;
    singleton?: boolean;
    useBaseServices?: boolean;
  } = {}
): INopePackageLoader {
  if (
    options.packageLoaderConstructorClass === null ||
    options.packageLoaderConstructorClass === undefined
  ) {
    options.packageLoaderConstructorClass = NopePackageLoader;
  }

  options = Object.assign(
    {
      packageLoaderConstructorClass: null,
      dispatcherConstructorClass: null,
      singleton: true,
      useBaseServices: true,
    },
    options
  );

  const create = () => {
    // Create a loader
    const loader = new options.packageLoaderConstructorClass();

    // load the default Package:
    loader
      .addPackage(
        generateNopeBasicPackage(dispatcherOptions, options.singleton)
      )
      .catch((e) => {
        throw e;
      });

    return loader;
  };

  if (options.singleton) {
    // Create a singaleton if required.
    // use the container to receive the
    // singleton object
    const container = getSingleton("nopeBackendPackageLoader.instance", create);

    return container.instance;
  }

  // No singleton is required =>
  // create a new instance.
  return create();
}