import {Injectable, NgZone} from '@angular/core';
import {Observable} from 'rxjs/Observable';
import {Observer} from 'rxjs/Observer';

import {SebmGoogleMapKmlLayer} from './../../directives/google-map-kml-layer';
import {GoogleMapsAPIWrapper} from './../google-maps-api-wrapper';
import {KmlLayer, KmlLayerOptions} from './../google-maps-types';

declare var google: any;

/**
 * Manages all KML Layers for a Google Map instance.
 */
@Injectable()
export class KmlLayerManager {
  private _layers: Map<SebmGoogleMapKmlLayer, Promise<KmlLayer>> =
      new Map<SebmGoogleMapKmlLayer, Promise<KmlLayer>>();

  constructor(private _wrapper: GoogleMapsAPIWrapper, private _zone: NgZone) {}

  /**
   * Adds a new KML Layer to the map.
   */
  addKmlLayer(layer: SebmGoogleMapKmlLayer) {
    const newLayer = this._wrapper.getNativeMap().then(m => {
      return new google.maps.KmlLayer(<KmlLayerOptions>{
        clickable: layer.clickable,
        map: m,
        preserveViewport: layer.preserveViewport,
        screenOverlays: layer.screenOverlays,
        suppressInfoWindows: layer.suppressInfoWindows,
        url: layer.url,
        zIndex: layer.zIndex
      });
    });
    this._layers.set(layer, newLayer);
  }

  setOptions(layer: SebmGoogleMapKmlLayer, options: KmlLayerOptions) {
    this._layers.get(layer).then(l => l.setOptions(options));
  }

  deleteKmlLayer(layer: SebmGoogleMapKmlLayer) {
    this._layers.get(layer).then(l => {
      l.setMap(null);
      this._layers.delete(layer);
    });
  }

  /**
   * Creates a Google Maps event listener for the given KmlLayer as an Observable
   */
  createEventObservable<T>(eventName: string, layer: SebmGoogleMapKmlLayer): Observable<T> {
    return Observable.create((observer: Observer<T>) => {
      this._layers.get(layer).then((m: KmlLayer) => {
        m.addListener(eventName, (e: T) => this._zone.run(() => observer.next(e)));
      });
    });
  }
}