import {Injectable} from '@angular/core';
import {ActivatedRouteSnapshot, CanActivate, Router, RouterStateSnapshot} from '@angular/router';
import {AuthService} from './auth.service';
import {Observable} from 'rxjs/internal/Observable';
import {map} from 'rxjs/operators';
import {ToasterService} from '../core/toaster.service';
import {User} from '../user/user';

@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {

  constructor(private auth: AuthService, private router: Router, private toaster: ToasterService) {
  }

  static checkUser(permission: string, user: User, router: Router, state: RouterStateSnapshot, toaster: ToasterService): boolean {
    if (!user.isAuthenticated) {
      router.navigate(['login'], {queryParams: {returnUrl: state.url}});
      toaster.show('Danger', 'User is not authenticated');
      return false;
    }
    const hasPermission = permission === undefined || user.perms.indexOf(permission) !== -1;
    if (!hasPermission) {
      toaster.show('Danger', 'You do not have the permission to access this area.');
    }
    return hasPermission;
  }

  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> | boolean {
    if (this.auth.user === undefined) {
      return this.auth.userObservable
        .pipe(
          map<User, boolean>((value: User) => AuthGuard.checkUser(
            route.data['permission'], value, this.router, state, this.toaster
          ))
        );
    }
    return AuthGuard.checkUser(route.data['permission'], this.auth.user, this.router, state, this.toaster);
  }
}