const {
  createDynamoDBEventProcessor,
  createWsHandler,
  DynamoDBConnectionManager,
  DynamoDBEventStore,
  DynamoDBSubscriptionManager,
  PubSub,
} = require('aws-lambda-graphql');
import { makeExecutableSchema } from 'graphql-tools';

// this only processes AWS Api Gateway v2 events
// if you want to process HTTP too, use createHttpHandler
// or you can use both, see chat-example-server

// instantiate event store
// by default uses Events table (can be changed)
const eventStore = new DynamoDBEventStore();
const pubSub = new PubSub({ eventStore });
const connectionManager = new DynamoDBConnectionManager();
const subscriptionManager = new DynamoDBSubscriptionManager();

const schema = makeExecutableSchema({
  typeDefs: /* GraphQL */ `
    type Mutation {
      publish(message: String!): String!
    }

    type Query {
      dummy: String!
    }

    type Subscription {
      messageFeed: String!
    }
  `,
  resolvers: {
    Query: {
      dummy: () => 'dummy',
    },
    Mutation: {
      publish: async (rootValue, { message }) => {
        await pubSub.publish('NEW_MESSAGE)', { message });

        return message;
      },
    },
    Subscription: {
      messageFeed: {
        // rootValue is same as object published using pubSub.publish
        resolve: rootValue => rootValue.message,
        subscribe: pubSub.subscribe('NEW_MESSAGE'),
      },
    },
  },
});

const eventProcessor = createDynamoDBEventProcessor({
  connectionManager,
  schema,
  subscriptionManager,
});
const wsHandler = createWsHandler({
  connectionManager,
  schema,
  subscriptionManager,
});

// use these handlers from your lambda and map them to
// api gateway v2 and DynamoDB events table
module.exports.consumeWsEvent = wsHandler;
module.exports.consumeDynamoDBStream = eventProcessor;

import { Client, WebSocketLink } from 'aws-lambda-ws-link';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloClient } from 'apollo-client';

const wsClient = new Client({
  uri: 'ws://localhost:8000',
});
const link = new WebSocketLink(client);
const client = new ApolloClient({
  cache: new InMemoryCache(),
  link,
});

// ...