/**
 * Copyright since 2025 Mifos Initiative
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

import { inject } from '@angular/core';
import { ActivatedRouteSnapshot, CanActivateFn, Router } from '@angular/router';
import { Observable, of } from 'rxjs';
import { catchError, map } from 'rxjs/operators';

import { ClientsService } from '../clients.service';
import { familyAllowed, nomineeAllowed } from './client-rules';

/**
 * Walk up the route snapshot tree until we find a `clientId` path param. The
 * family-members / nominees routes are nested two levels under the client
 * shell, so simple `route.params['clientId']` returns undefined.
 */
function findClientId(route: ActivatedRouteSnapshot): string | null {
  let cur: ActivatedRouteSnapshot | null = route;
  while (cur) {
    const id = cur.params?.['clientId'];
    if (id) return id;
    cur = cur.parent;
  }
  return null;
}

/**
 * Build a guard that redirects to the client's General tab when the client
 * isn't eligible for the section. Resolves the client lazily so we don't
 * couple the guard to any specific parent resolver.
 */
function makeEligibilityGuard(
  predicate: (legalFormId: number | null | undefined, constitutionLabel?: string | null) => boolean
): CanActivateFn {
  return (route) => {
    const router = inject(Router);
    const clientsService = inject(ClientsService);
    const clientId = findClientId(route);
    // No clientId in the URL — let the framework's own missing-param handling kick in.
    if (!clientId) return true;

    return clientsService.getClientData(clientId).pipe(
      map((client: any) => {
        const legalFormId = client?.legalForm?.id;
        const constitutionLabel = client?.clientNonPersonDetails?.constitution?.name || '';
        if (predicate(legalFormId, constitutionLabel)) return true;
        return router.createUrlTree([
          '/clients',
          clientId,
          'general'
        ]);
      }),
      // If the client lookup fails, fail open and let downstream handle it
      // rather than redirecting users into an infinite loop on a stale URL.
      catchError(() => of(true))
    ) as Observable<boolean | ReturnType<Router['createUrlTree']>>;
  };
}

export const familyAllowedGuard: CanActivateFn = makeEligibilityGuard(familyAllowed);
export const nomineeAllowedGuard: CanActivateFn = makeEligibilityGuard(nomineeAllowed);