import { Injectable } from '@angular/core';
import { ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree, CanDeactivate } from '@angular/router';
import { Observable } from 'rxjs';

export interface GuardedComponent {
  destroyMsg: string;
  canDestroy(): boolean;
}

@Injectable({
  providedIn: 'root',
})
export class ConfirmDeactivateGuardGuard implements CanDeactivate<GuardedComponent> {
  canDeactivate(component: GuardedComponent,
      currentRoute: ActivatedRouteSnapshot,
      currentState: RouterStateSnapshot,
      nextState?: RouterStateSnapshot): boolean | UrlTree | Observable<boolean | UrlTree> | Promise<boolean | UrlTree> {
    // console.log('deactivate check');
    if (component.canDestroy()) {
      return true;
    } else {
      return window.confirm(component.destroyMsg);
    }
  }
}