import { fadeIn, fadeInOut } from '../../shared/animations/fade';
import { ChangeDetectionStrategy, Component, Injector, OnInit } from '@angular/core';
import { ActivatedRoute, CanActivate, Route, Router } from '@angular/router';
import { RemoteData } from '../../core/data/remote-data';
import { Item } from '../../core/shared/item.model';
import { combineLatest as observableCombineLatest, Observable, of as observableOf } from 'rxjs';
import { map } from 'rxjs/operators';
import { isNotEmpty } from '../../shared/empty.util';
import { getItemPageRoute } from '../item-page-routing-paths';
import { GenericConstructor } from '../../core/shared/generic-constructor';

@Component({
  selector: 'ds-edit-item-page',
  templateUrl: './edit-item-page.component.html',
  changeDetection: ChangeDetectionStrategy.OnPush,
  animations: [
    fadeIn,
    fadeInOut
  ]
})
/**
 * Page component for editing an item
 */
export class EditItemPageComponent implements OnInit {

  /**
   * The item to edit
   */
  itemRD$: Observable<RemoteData<Item>>;

  /**
   * The current page outlet string
   */
  currentPage: string;

  /**
   * All possible page outlet strings
   */
  pages: { page: string, enabled: Observable<boolean> }[];

  constructor(private route: ActivatedRoute, private router: Router, private injector: Injector) {
    this.router.events.subscribe(() => {
      this.currentPage = this.route.snapshot.firstChild.routeConfig.path;
    });
  }

  ngOnInit(): void {
    this.pages = this.route.routeConfig.children
      .filter((child: Route) => isNotEmpty(child.path))
      .map((child: Route) => {
        let enabled = observableOf(true);
        if (isNotEmpty(child.canActivate)) {
          enabled = observableCombineLatest(child.canActivate.map((guardConstructor: GenericConstructor<CanActivate>) => {
              const guard: CanActivate = this.injector.get<CanActivate>(guardConstructor);
              return guard.canActivate(this.route.snapshot, this.router.routerState.snapshot);
            })
          ).pipe(
            map((canActivateOutcomes: any[]) => canActivateOutcomes.every((e) => e === true))
          );
        }
        return { page: child.path, enabled: enabled };
      }); // ignore reroutes
    this.itemRD$ = this.route.data.pipe(map((data) => data.dso));
  }

  /**
   * Get the item page url
   * @param item The item for which the url is requested
   */
  getItemPage(item: Item): string {
    return getItemPageRoute(item);
  }
}