import { Optional, Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { SwPush } from '@angular/service-worker';
import { Observable } from 'rxjs';

import { environment } from '../../environments/environment';
import { PushNotification } from './notification';

@Injectable({
  providedIn: 'root'
})
export class NotificationService {

  constructor(
    private http: HttpClient,
    @Optional() private swPush: SwPush
  ) { }

  activate(): Observable<void> {
    return Observable.create((observer) => {
      this.swPush.requestSubscription({
        serverPublicKey: environment.webPush.publicKey
      }).then((subscription: PushSubscription) => {
        this.http.post(`${environment.serverUrl}/subscription`, subscription).subscribe(() => {
          observer.next();
          observer.complete();
        }, (err) => {
          observer.error(err);
        });
      }).catch((err) => {
        console.log(err): // => Here an error occurs on Safari : TypeError: undefined is not an object (evaluating 't.subscribe')
        observer.error(err);
      });
    });
  }

  sendNotification(notification: PushNotification): Observable<void> {
    return this.http.post<void>(`${environment.serverUrl}/notification`, notification);
  }

  messages(): Observable<PushNotification> {
    return <Observable<PushNotification>>this.swPush.messages;
  }
}