import { ActivatedRouteSnapshot, CanActivate, Router, RouterStateSnapshot } from '@angular/router';
import {Injectable, Injector} from '@angular/core';
import { Observable } from "rxjs";
// code from https://stackoverflow.com/questions/45618687/angular-2-router-guards-order

@Injectable()
export class CompositeRouteGuard implements CanActivate {

  constructor(  protected router: Router,
                protected injector: Injector ) {
  }

  canActivate( route: ActivatedRouteSnapshot, state: RouterStateSnapshot ): Observable<boolean> {
    var compositeCanActivateObservable: Observable<boolean> = Observable.of(true);

    let routeGuards = route.data.routeGuards;

    if(routeGuards){
      for( var i = 0; i < routeGuards.length; i++ ){
        let routeGuard = this.injector.get(routeGuards[i]);
        let canActivateObservable = routeGuard.canActivate(route, state);
        compositeCanActivateObservable = compositeCanActivateObservable.flatMap( (bool) => {
          if(!bool){
            return Observable.of(false);
          }
          else{
            return canActivateObservable;
          }
        });
      }
    }

    return compositeCanActivateObservable;
  }
}