// src/hooks/mutations/useAddWatchedItemMutation.ts
import { useMutation, useQueryClient } from '@tanstack/react-query';
import * as apiClient from '../../services/apiClient';
import { notifySuccess, notifyError } from '../../services/notificationService';

interface AddWatchedItemParams {
  itemName: string;
  category?: string;
}

/**
 * Mutation hook for adding an item to the user's watched items list.
 *
 * This hook provides optimistic updates and automatic cache invalidation.
 * When the mutation succeeds, it invalidates the watched-items query to
 * trigger a refetch of the updated list.
 *
 * @returns Mutation object with mutate function and state
 *
 * @example
 * ```tsx
 * const addWatchedItem = useAddWatchedItemMutation();
 *
 * const handleAdd = () => {
 *   addWatchedItem.mutate(
 *     { itemName: 'Milk', category: 'Dairy' },
 *     {
 *       onSuccess: () => console.log('Added!'),
 *       onError: (error) => console.error(error),
 *     }
 *   );
 * };
 * ```
 */
export const useAddWatchedItemMutation = () => {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: async ({ itemName, category }: AddWatchedItemParams) => {
      const response = await apiClient.addWatchedItem(itemName, category ?? '');

      if (!response.ok) {
        const error = await response.json().catch(() => ({
          message: `Request failed with status ${response.status}`,
        }));
        throw new Error(error.message || 'Failed to add watched item');
      }

      return response.json();
    },
    onSuccess: () => {
      // Invalidate and refetch watched items to get the updated list
      queryClient.invalidateQueries({ queryKey: ['watched-items'] });
      notifySuccess('Item added to watched list');
    },
    onError: (error: Error) => {
      notifyError(error.message || 'Failed to add item to watched list');
    },
  });
};