interact.ts

import RuntimeClientFactory, { TraceType } from '@voiceflow/runtime-client-js';
import dotenv from 'dotenv';
import { RequestHandler } from 'express';

import { sendImage, sendMessage, sendTypingStatus } from './request';
import kvstore from './store';

// load in environment variables from .env file
dotenv.config();

const runtimeClientFactory = new RuntimeClientFactory({
  versionID: process.env.VOICEFLOW_VERSION_ID!, // voiceflow project versionID
  apiKey: process.env.VOICEFLOW_API_KEY!, // voiceflow api key
  endpoint: process.env.VOICEFLOW_RUNTIME_ENDPOINT,
});

// fetch the conversation state from persistence
const getState = async (senderID: string, appID: string): Promise<any | undefined> => {
  const stateKey = `${appID}-${senderID}`;
  return kvstore.get(stateKey);
};

// save the conversations tate to persistence
const saveState = async (senderID: string, appID: string, state: any) => {
  const stateKey = `${appID}-${senderID}`;
  return kvstore.set(stateKey, state);
};

const handleMessage = async (senderID: string, appID: string, message: string): Promise<any> => {
  const state = await getState(senderID, appID);
  const client = runtimeClientFactory.createClient(state);

  client.onSpeak(async (trace, context, index) => {
    // get the index of the last speak trace
    const lastSpeakIndex = context
      .getTrace()
      .map(({ type }) => type)
      .lastIndexOf(TraceType.SPEAK);
    const chips = context.getChips().map(({ name }) => name);

    const quickReplies = index === lastSpeakIndex ? chips : [];
    await sendMessage(trace.payload.message, quickReplies, senderID);
  });

  client.onVisual(async (trace) => {
    if (trace.payload.image) {
      await sendImage(trace.payload.image, senderID);
    }
  });

  const context = await client.sendText(message);
  await saveState(senderID, appID, context.toJSON().state);

  return 'ok';
};

const interact: RequestHandler = async (req, res) => {
  const { body } = req;
  if (body.object !== 'page') {
    res.sendStatus(404);
    return;
  }

  // Iterates over each entry - there may be multiple if batched
  body.entry.forEach(async (entry: any) => {
    // do not handle messages older than 5 seconds
    if (Date.now() - entry.time > 5000) {
      return;
    }

    // Gets the body of the webhook event
    const webhookEvent = entry.messaging[0];

    // Discard uninteresting events
    if ('read' in webhookEvent) {
      // console.log("Got a read event");
      return;
    }

    if ('delivery' in webhookEvent) {
      // console.log("Got a delivery event");
      return;
    }

    // SenderID -> Who is interacting with the app?
    // AppID -> What is the target "skill"?
    // Message -> Text
    await sendTypingStatus(true, webhookEvent.sender.id);
    await handleMessage(webhookEvent.sender.id, webhookEvent.recipient.id, webhookEvent.message.text);
    await sendTypingStatus(false, webhookEvent.sender.id);
  });

  res.send('EVENT_RECEIVED');
};

export default interact;