import { ContentControlModel } from '../../models/controls/ContentControlModel';
import { IRegion } from '../IRegion';
import { Region } from '../Region';
import { RegionAdapterBase } from '../RegionAdapterBase';
import { IRegionBehaviorFactory } from '../IRegionBehaviorFactory';
import { injectable, inject } from 'tsyringe';
import { regionBehaviorFactoryInjectionToken } from '../injectionTokens';
import {
  CollectionChangeAction,
  iuCount,
  iuFirstOrDefault,
} from '../../baseframework/collections';
import { SingleActiveRegion } from '../SingleActiveRegion';

/**
 *  Adapter for content control
 *  Allows the use of content control to host regions
 *
 * @export
 * @class AdapterForContentControl
 * @extends {RegionAdapterBase<ContentControlModel>}
 * @wType Microsoft.Practices.Prism.Regions.ContentControlRegionAdapter
 */
@injectable()
export class AdapterForContentControl extends RegionAdapterBase<ContentControlModel> {
  /**
   * Creates an instance of AdapterForContentControl.
   * @param {IRegionBehaviorFactory} factory
   * @memberof AdapterForContentControl
   */
  constructor(
    @inject(regionBehaviorFactoryInjectionToken) factory: IRegionBehaviorFactory
  ) {
    super(factory);
  }

  /**
   * Adapts the content control with the specific region
   *
   * @protected
   * @param {IRegion} region  region to adapt
   * @param {ContentControlModel} regionTarget  content control to adapt
   * @memberof AdapterForContentControl
   */
  protected Adapt(region: IRegion, regionTarget: ContentControlModel): void {
    region.ActiveViews.CollectionChanged.addHandler((e, a) => {
      regionTarget.Content = iuFirstOrDefault(region.ActiveViews);
    });

    region.Views.CollectionChanged.addHandler((sender, e) => {
      if (
        e.action != CollectionChangeAction.Add ||
        iuCount(region.ActiveViews) != 0
      )
        return;

      region.Activate(e.NewItems.getItem(0));
    });
  }

  protected CreateRegion(): IRegion {
    return new SingleActiveRegion();
  }
}