import {
  Inject,
  Injectable,
  Optional,
} from '@angular/core';
import { ReplaySubject } from 'rxjs';
import {
  mergeMapTo,
  tap,
} from 'rxjs/operators';
import { RXAP_REQUEST_CLOUD_MESSAGING_TOKEN } from './tokens';
import { AngularFireMessaging } from '@angular/fire/compat/messaging';

export interface Message {
  collapse_key: string;
  from: string;
  notification: {
    body: string;
    click_action: string;
    title: string;
  };
}

@Injectable({ providedIn: 'root' })
export class RxapFirebaseMessagingService {
  public token$ = new ReplaySubject<string | null>(1);

  constructor(
    @Inject(AngularFireMessaging)
    public readonly messaging: AngularFireMessaging,
    @Optional()
    @Inject(RXAP_REQUEST_CLOUD_MESSAGING_TOKEN)
    public readonly requestPermissionImminently = false,
  ) {
    this.messaging.messages
        .pipe(
          tap((message: any) =>
            this.showNotification(
              message.notification.title,
              message.notification.body,
            ),
          ),
        )
        .subscribe();
    if (this.requestPermissionImminently) {
      this.requestPermission();
    }
  }

  public requestPermission() {
    console.log('request notification permission');
    this.messaging.requestPermission
        .pipe(mergeMapTo(this.messaging.tokenChanges))
        .subscribe(
          (token) => {
            console.info('cloud messaging permission is granted');
            this.token$.next(token);
          },
          () => console.error('cloud messaging permission is denied'),
        );
  }

  public showNotification(title: string, body: string): void {
    // Let's check if the browser supports notifications
    if (!('Notification' in window)) {
      alert('This browser does not support desktop notification');
    }

    // Let's check whether notification permissions have already been granted
    else if (Notification.permission === 'granted') {
      // If it's okay let's create a notification
      new Notification(title, { body });
    } else {
      console.warn('Notification permission is not granted');
    }
  }
}