import { ApolloClient } from 'apollo-client';
import { ApolloLink } from 'apollo-link';
import { createHttpLink } from 'apollo-link-http';
import { defaultDataIdFromObject, InMemoryCache } from 'apollo-cache-inmemory';

import { BACKEND } from './vars';

import { AppContext, PluginParams } from './index';
const isBrowser = typeof window !== 'undefined';

const base = isBrowser ? location.origin + '/graphql' : BACKEND;

const httpLink = createHttpLink({
    uri: base,
    useGETForQueries: true,
});

export function getClient({ initialState = {} } = {}): ApolloClient<any> {
    return new ApolloClient({
        link: ApolloLink.from([httpLink]),
        cache: new InMemoryCache({
            dataIdFromObject: (object: any): any => {
                switch (object.__typename) {
                    case 'EntityUrl':
                        return `${object.type}-${object.id}`; // use `type + id` as the primary key
                    default:
                        return defaultDataIdFromObject(object); // fall back to default handling
                }
            },
        }).restore(initialState),
    });
}

export function apolloClientPlugin(params: PluginParams, appCtx: AppContext): AppContext {
    const client = getClient(params.initialGQLState);
    return {
        ...appCtx,
        client,
    };
}