import { isPlatformServer } from '@angular/common';
import { Inject, Injectable, PLATFORM_ID } from '@angular/core';
import { EMPTY, fromEvent, Observable } from 'rxjs';
import { filter, map } from 'rxjs/operators';

@Injectable({
  providedIn: 'root',
})
/**
 * Post Message Service handles communication with child iframe
 */
export class PostMessageIframeService {
  constructor(@Inject(PLATFORM_ID) private platformId: object) {}

  /**
   * Sends post message to child iframe
   * @param iframeElement
   * @param data
   */
  sendMessage(iframeElement: HTMLIFrameElement, data: any): void {
    iframeElement.contentWindow.postMessage(data, '*');
  }

  getMessages(): Observable<any> {
    return fromEvent<MessageEvent>(window, 'message').pipe(
      filter((e) => e.origin.includes('dane.gov.pl')),
      map((e) => e.data),
    );
  }
}
