import ExtraInfo from '../../../features/extraInfo/core';
import AutoRefresh from '../../../features/autoRefresh/core/autoRefresh';

export const AutoRefreshDependency = 'autoRefresh';
export const ExtraInfoDependency = 'extraInfo';
export const DependenciesToClass = {
  [AutoRefreshDependency]: AutoRefresh,
  [ExtraInfoDependency]: ExtraInfo,
};

interface OurWindow extends Window {
  TWPTDependencies?: Dependencies;
}

export type ClassFromDependency<T extends Dependency> = InstanceType<
  (typeof DependenciesToClass)[T]
>;

type Dependencies = {
  [K in Dependency]?: ClassFromDependency<K>;
};

export type Dependency = keyof typeof DependenciesToClass;

class DependenciesProvider {
  private dependencies: Dependencies;

  constructor() {
    const ourWindow = window as OurWindow;
    if (!ourWindow.TWPTDependencies) {
      ourWindow.TWPTDependencies = {};
    }
    this.dependencies = ourWindow.TWPTDependencies;
  }

  /**
   * Gets an instance of a dependency, and creates it beforehand if it doesn't exist yet.
   */
  getDependency<T extends Dependency>(dependency: T): ClassFromDependency<T> {
    this.setUpDependency(dependency);
    const dep = this.dependencies[dependency];
    if (!dep) {
      throw new Error(`Dependency ${dependency} not found.`);
    }
    return dep;
  }

  setUpDependency<T extends Dependency>(dependency: T): void {
    if (!this.dependencies[dependency]) {
      const dependencyClass = DependenciesToClass[dependency];
      this.dependencies[dependency] = new dependencyClass() as Dependencies[T];
    }
  }
}

export default class DependenciesProviderSingleton {
  private static instance: DependenciesProvider;

  /**
   * @see {@link DependenciesProviderSingleton.getInstance}
   */
  private constructor() {}

  public static getInstance(): DependenciesProvider {
    if (!DependenciesProviderSingleton.instance) {
      DependenciesProviderSingleton.instance = new DependenciesProvider();
    }
    return DependenciesProviderSingleton.instance;
  }
}