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

export interface CanComponentDeactivate {
    canDeactivate: () => Observable<boolean> | boolean;
}

@Injectable()
export class CanDeactivateGuardService implements CanDeactivate<CanComponentDeactivate> {
    canDeactivate(
        component: CanComponentDeactivate,
        currentRoute: ActivatedRouteSnapshot,
        currentState: RouterStateSnapshot,
        nextState?: RouterStateSnapshot): boolean | Observable<boolean> {
        return component.canDeactivate() ? component.canDeactivate() : true;
    }
}