/*
 * Copyright (c) 2022. Deutsche Telekom AG
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 */


import { Injectable } from '@angular/core';
import { Observable, Subject } from 'rxjs';
import { filter } from 'rxjs/operators';

import { Alert, AlertType } from './alert.model';

@Injectable({ providedIn: 'root' })
export class AlertService {
  private subject = new Subject<Alert>();
  private defaultId = 'default-alert';

  // enable subscribing to alerts observable
  onAlert(id = this.defaultId): Observable<Alert> {
    return this.subject.asObservable().pipe(filter(x => x && x.id === id));
  }
  get alerts() {
    return this.subject;
  }

  // convenience methods
  success(message: string, options?: Partial<Alert>) {
    this.alert(new Alert({ ...options, type: AlertType.Success, message }));
  }

  error(message: string, options?: Partial<Alert>) {
    this.alert(new Alert({ ...options, type: AlertType.Error, message }));
  }

  info(message: string, options?: Partial<Alert>) {
    this.alert(new Alert({ ...options, type: AlertType.Info, message }));
  }

  warn(message: string, options?: Partial<Alert>) {
    this.alert(new Alert({ ...options, type: AlertType.Warning, message }));
  }

  // main alert method
  alert(alert: Alert) {
    alert.id = alert.id || this.defaultId;
    this.subject.next(alert);
  }

  // clear alerts
  clear(id = this.defaultId) {
    this.subject.next(new Alert({ id }));
  }
}