import { errors, request as spreeSdkRequestHelpers } from '@spree/storefront-api-v2-sdk';
import type { CreateCustomizedFetchFetcher } from '@spree/storefront-api-v2-sdk/types/interfaces/CreateCustomizedFetchFetcher';
import isJsonContentType from './is-json-content-type';

export const fetchResponseKey = Symbol('fetch-response-key');

const createCustomizedFetchFetcher: CreateCustomizedFetchFetcher = (fetcherOptions) => {
  const { FetchError } = errors;
  const sharedHeaders = {
    'Content-Type': 'application/json'
  };

  const { host, fetch, requestConstructor } = fetcherOptions;

  return {
    fetch: async (fetchOptions) => {
      // This fetcher always returns request equal null,
      // because @vercel/fetch doesn't accept a Request object as argument
      // and it's not used by NJC anyway.
      try {
        const { url, params, method, headers, responseParsing } = fetchOptions;
        const absoluteUrl = new URL(url, host);
        let payload;

        switch (method.toUpperCase()) {
          case 'PUT':
          case 'POST':
          case 'DELETE':
          case 'PATCH':
            payload = { body: JSON.stringify(params) };
            break;
          default:
            payload = null;
            absoluteUrl.search = spreeSdkRequestHelpers.objectToQuerystring(params);
        }

        const request: Request = new requestConstructor(absoluteUrl.toString(), {
          method: method.toUpperCase(),
          headers: { ...sharedHeaders, ...headers },
          ...payload
        });

        try {
          const response: Response = await fetch(request);
          const responseContentType = response.headers.get('content-type');
          let data;

          if (responseParsing === 'automatic') {
            if (responseContentType && isJsonContentType(responseContentType)) {
              data = await response.json();
            } else {
              data = await response.text();
            }
          } else if (responseParsing === 'text') {
            data = await response.text();
          } else if (responseParsing === 'json') {
            data = await response.json();
          } else if (responseParsing === 'stream') {
            data = await response.body;
          }

          if (!response.ok) {
            // Use the "traditional" approach and reject non 2xx responses.
            throw new FetchError(response, request, data);
          }

          data[fetchResponseKey] = response;

          return { data };
        } catch (error) {
          if (error instanceof FetchError) {
            throw error;
          }

          if (!(error instanceof Error)) {
            throw error;
          }

          throw new FetchError(null, request, null, error.message);
        }
      } catch (error) {
        if (error instanceof FetchError) {
          throw error;
        }

        if (!(error instanceof Error)) {
          throw error;
        }

        throw new FetchError(null, null, null, error.message);
      }
    }
  };
};

export default createCustomizedFetchFetcher;