import useSWR, { responseInterface } from 'swr';
import _ from 'lodash';
import { get } from '../requests';

type Response<T> = responseInterface<T, Error>;

const fetcher = (endpoint: string) => get(endpoint).then(response => response.data);

const hooks: any = {};

const registerServiceHooks = <Item = any>(service: string): void => {
  if (hooks[service]) return;

  const useList = (query = '', options = {}): Response<Item[]> => {
    return useSWR(`/${service}${query}`, fetcher, options);
  };

  const useItem = (_id: string): Response<Item> => {
    const { data: preloadedItems } = useList('', { revalidateOnMount: false });
    const result = useSWR(_id && `/${service}/${_id}`, fetcher);
    if (!result.data && result.isValidating) {
      // If we are waiting for the first result, check if we can maybe
      // get the data from already cached list for the time-being
      const item = _.find(preloadedItems, { _id });
      return { ...result, data: item } as Response<Item>;
    }
    return result;
  };

  hooks[service] = { useItem, useList };
};

hooks.account = {
  useList: () => {
    const { data: transfers } = useSWR('/transfers', fetcher);
    const dates = _.groupBy(transfers, 'date');
    const dataUnsorted = _.map(dates, (dateTransfers, date) => ({
      _id: dateTransfers[0]._id, // fake: sample id for unique key
      date,
      amount: _
        .sumBy(dateTransfers, transfer => transfer.amount * (transfer.operation === 'in' ? 1 : -1))
        .toFixed(1),
    }));
    const data = _.sortBy(dataUnsorted, 'date').reverse();
    return { data };
  },
};


export { registerServiceHooks };
export default hooks;