import reduceDocument, {createTypeGetter} from '../graphql/reduceDocument';
import {addTypenameToDocument} from 'apollo-client/queries/queryTransform';

/**
 * createHistory returns the history service for react router
 * @param  {string}  basename  base path of the url
 * @return {Object}  histor service
 */
export function createGraphQLService(registry, introspectionData) {
  const typeGetter = createTypeGetter(introspectionData);

  // Use shared fragment map.
  // Attention: Fragment names must be unique otherwise weird things will happen.
  const fragmentMap = {};

  return {
    registry,
    resolveDocument(documentOrCallback, props, context) {
      let document = typeof documentOrCallback === 'function'
        ? documentOrCallback(props, context)
        : documentOrCallback;
      document = reduceDocument(registry.resolveFragments(document), {typeGetter, fragmentMap});

      // We also add typenames to the document which apollo would usually do,
      // but we also use the network interface in subscriptions directly
      // which require the resolved typenames.
      return addTypenameToDocument(document);
    },
  };
}