graycoreio/daffodil

import {
  Injectable,
  Inject,
} from '@angular/core';
import {
  Router,
  UrlTree,
} from '@angular/router';
import { Observable } from 'rxjs';
import {
  tap,
  filter,
  take,
  map,
} from 'rxjs/operators';

import {
  DaffCartFacade,
  DaffCartResolveState,
} from '@daffodil/cart/state';

import {
  DaffCartRoutingConfiguration,
  DAFF_CART_ROUTING_CONFIG,
} from '../../config/config';

/**
 * A routing guard that will optionally redirect to a given url if the cart is not properly resolved.
 * It will initiate cart resolution.
 * The url has no default and the guard will not redirect if no value is specified.
 * Specify a redirect path with the {@link DaffResolvedCartGuardRedirectUrl} injection token.
 * The guard will wait until the cart has been resolved before performing the check and emitting.
 */
@Injectable({
  providedIn: 'root',
})
export class DaffResolvedCartGuard  {
  constructor(
    private facade: DaffCartFacade,
    private router: Router,
    @Inject(DAFF_CART_ROUTING_CONFIG) private config: DaffCartRoutingConfiguration,
  ) {}

  canActivate(): Observable<boolean | UrlTree> {
    return this.facade.resolved$.pipe(
      filter(
        resolvedState =>
          resolvedState === DaffCartResolveState.Succeeded ||
                    resolvedState === DaffCartResolveState.ServerSide ||
                    resolvedState === DaffCartResolveState.Failed,
      ),
      map(
        resolvedState =>
          resolvedState === DaffCartResolveState.Succeeded ||
                    resolvedState === DaffCartResolveState.ServerSide,
      ),
      take(1),
      map(success =>
        !success && this.config.resolution.failedResolutionPath
          ?    this.router.parseUrl(
            this.config.resolution.failedResolutionPath,
          )
          : success,
      ),
    );
  }
}