///
/// Copyright 2015-2026 Micro Focus or one of its affiliates.
///
/// 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.
///

import { Injectable, OnDestroy } from '@angular/core';
import { BehaviorSubject, Subscription } from 'rxjs';
import { filter } from 'rxjs/operators';
import { CardTabComponent } from './card-tab/card-tab.component';

@Injectable()
export class CardTabsService implements OnDestroy {
  tab$ = new BehaviorSubject<CardTabComponent>(null);
  tabs$ = new BehaviorSubject<CardTabComponent[]>([]);
  position$ = new BehaviorSubject<string>('top');

  private readonly _subscription: Subscription;

  constructor() {
    // when a tab is added or removed ensure we always select one if any are available
    this._subscription = this.tabs$
      .pipe(filter(tabs => !this.tab$.value || !tabs.find(tab => tab === this.tab$.value)))
      .subscribe(tabs => this.tab$.next(tabs.length > 0 ? tabs[0] : null));
  }

  ngOnDestroy(): void {
    this._subscription.unsubscribe();
  }

  /**
   * Add a tab to the list of tabs
   */
  addTab(tab: CardTabComponent): void {
    this.tabs$.next([...this.tabs$.value, tab]);
  }

  /**
   * Remove a tab from the list
   */
  removeTab(tab: CardTabComponent): void {
    this.tabs$.next(this.tabs$.value.filter(_tab => _tab !== tab));
  }

  /**
   * Select the tab
   */
  select(tab: CardTabComponent): void {
    this.tab$.next(tab);
  }

  /**
   * Set the position of the tab content
   */
  setPosition(position: string): void {
    this.position$.next(position);
  }
}