import { Injectable } from '@angular/core';
import { Params } from '@angular/router';
import {
  ActivatedRouterStateSnapshot,
  Breadcrumb,
  PageType,
  ProductSearchPage,
  RoutingService,
} from '@spartacus/core';
import { Observable } from 'rxjs';
import { filter, map, pluck, switchMap } from 'rxjs/operators';
import { ProductListComponentService } from '../../container/product-list-component.service';
import { FacetList } from '../facet.model';

/**
 * Provides access to all the facets and active facets for the Product Listing Page.
 */
@Injectable({
  providedIn: 'root',
})
export class ProductFacetService {
  constructor(
    protected routing: RoutingService,
    protected productListComponentService: ProductListComponentService
  ) {}

  protected readonly routeState$ = this.routing
    .getRouterState()
    .pipe(pluck('state'));

  /**
   * Returns the search results for the current page.
   */
  protected readonly searchResult$: Observable<ProductSearchPage> =
    this.routeState$.pipe(
      switchMap((state) =>
        this.productListComponentService.model$.pipe(
          filter((page) => this.filterForPage(state, page)),
          map((page) => ({
            ...page,
            breadcrumbs: this.filterBreadcrumbs(
              page?.breadcrumbs ?? [],
              state.params
            ),
          }))
        )
      )
    );

  /**
   * Observes the facets and active facets for the given page. The facet data
   * is provided in a `FacetList`.
   */
  readonly facetList$: Observable<FacetList> = this.searchResult$.pipe(
    map(
      (result: ProductSearchPage) =>
        ({
          facets: result.facets,
          activeFacets: result.breadcrumbs,
        } as FacetList)
    )
  );

  /**
   * Filters the current result by verifying if the result is related to the page.
   * This is done to avoid a combination of the next page and the current search results.
   */
  protected filterForPage(
    state: ActivatedRouterStateSnapshot,
    page: ProductSearchPage
  ): boolean {
    if (!page.currentQuery?.query?.value) {
      return false;
    }
    if (state.context.type === PageType.CATEGORY_PAGE) {
      return (
        page.currentQuery.query.value.indexOf(
          `allCategories:${state.context.id}`
        ) > -1
      );
    }

    if (
      state.context.type === PageType.CONTENT_PAGE &&
      state.context.id === 'search'
    ) {
      return page.currentQuery.query.value.startsWith(`${state.params.query}:`);
    }
    return false;
  }

  /**
   * Filter breadcrumbs which are not actively selected but coming from
   * the route navigation.
   *
   * The breadcrumbs might include the active category page code, which is not actively
   * selected by the user.
   */
  protected filterBreadcrumbs(
    breadcrumbs: Breadcrumb[],
    params: Params
  ): Breadcrumb[] {
    return breadcrumbs
      ? breadcrumbs.filter(
          (breadcrumb) =>
            !(
              breadcrumb.facetCode === 'allCategories' &&
              (breadcrumb.facetValueCode === params.categoryCode ||
                breadcrumb.facetValueCode === params.brandCode)
            )
        )
      : [];
  }
}