proposal-system/web/src/domain/customers/use-cases.ts

// Customers domain — TanStack Query hooks + query keys (the only public surface).
import { keepPreviousData, useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { toast } from 'react-toastify';
import { customersApi } from './api';
import type { CreateCustomerRequest, CustomerListParams, UpdateCustomerRequest } from './types';

export const customersKeys = {
  all: ['customers'] as const,
  lists: () => [...customersKeys.all, 'list'] as const,
  list: (params: CustomerListParams) => [...customersKeys.lists(), params] as const,
  search: (query: string) => [...customersKeys.all, 'search', query] as const,
};

/** Name autocomplete (ProposalFormPage). Call with the debounced input;
 *  disabled below 2 characters, matching current page behavior. */
export function useCustomerSearch(query: string) {
  return useQuery({
    queryKey: customersKeys.search(query),
    queryFn: () => customersApi.search(query),
    enabled: query.trim().length >= 2,
  });
}

/** Paginated management list (CustomerManagementPage). keepPreviousData
 *  keeps rows/totalCount rendered while a new page/search fetches (matches
 *  the old usePaginatedList behavior and keeps TablePagination's count from
 *  collapsing to 0 mid-fetch). */
export function useCustomerList(params: CustomerListParams = {}) {
  return useQuery({
    queryKey: customersKeys.list(params),
    queryFn: () => customersApi.list(params),
    placeholderData: keepPreviousData,
  });
}

export function useCreateCustomer() {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: (data: CreateCustomerRequest) => customersApi.create(data),
    onSuccess: () => {
      // Invalidate the whole domain: lists AND cached search-autocomplete
      // results (['customers','search',q]), which lists() would not cover —
      // otherwise a just-created customer is invisible in New Proposal's
      // autocomplete for the 5-minute staleTime.
      queryClient.invalidateQueries({ queryKey: customersKeys.all });
      toast.success('Customer created');
    },
    onError: (error: Error) => {
      toast.error(`Failed to create customer: ${error.message}`);
    },
  });
}

export function useUpdateCustomer() {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: ({ id, data }: { id: string; data: UpdateCustomerRequest }) =>
      customersApi.update(id, data),
    onSuccess: () => {
      // Whole-domain invalidation — see useCreateCustomer.
      queryClient.invalidateQueries({ queryKey: customersKeys.all });
      toast.success('Customer updated');
    },
    onError: (error: Error) => {
      toast.error(`Failed to update customer: ${error.message}`);
    },
  });
}