index.js

'use strict';

const admin = require('firebase-admin');
admin.initializeApp();
const functions = require('firebase-functions'); // Cloud Functions for Firebase library
const DialogflowApp = require('actions-on-google').DialogflowApp; // Google Assistant helper library
exports.dialogflowFirebaseFulfillment = functions.https.onRequest((request, response) => {
  console.log('Dialogflow Request headers: ' + JSON.stringify(request.headers));
  console.log('Dialogflow Request body: ' + JSON.stringify(request.body));
  if (request.body.queryResult) {
    processV2Request(request, response);
  } else {
    console.log('Invalid Request');
    return response.status(400).end('Invalid Webhook Request (expecting v2 webhook request)');
  }
});


/*
* Function to handle v2 webhook requests from Dialogflow
*/
function processV2Request (request, response) {
  // An action is a string used to identify what needs to be done in fulfillment
  let action = (request.body.queryResult.action) ? request.body.queryResult.action : 'default';
  // Parameters are any entites that Dialogflow has extracted from the request.
  let parameters = request.body.queryResult.parameters || {}; // https://dialogflow.com/docs/actions-and-parameters
  // Contexts are objects used to track and store conversation state
  let inputContexts = request.body.queryResult.contexts; // https://dialogflow.com/docs/contexts
  // Get the request source (Google Assistant, Slack, API, etc)
  let requestSource = (request.body.originalDetectIntentRequest) ? request.body.originalDetectIntentRequest.source : undefined;
  // Get the session ID to differentiate calls from different users
  let session = (request.body.session) ? request.body.session : undefined;
  // Create handlers for Dialogflow actions as well as a 'default' handler
  const actionHandlers = {
    // The default welcome intent has been matched, welcome the user (https://dialogflow.com/docs/events#default_welcome_intent)
    'input.welcome': () => {
      sendResponse('Hello, Welcome to Brighton Tide. Try asking for the next low tide.'); // Send simple response to user
    },
    // The default fallback intent has been matched, try to recover (https://dialogflow.com/docs/intents#fallback_intents)
    'input.unknown': () => {
      // Use the Actions on Google lib to respond to Google requests; for other requests use JSON
      sendResponse('I\'m having trouble understanding. Try asking for the next low tide.'); // Send simple response to user
    },
    'next-low': () => {

        var db = admin.firestore();

        const now = new Date();
        const nowUtc = now.getTime();
        
        const sameDay = (tide, date) => date.toISOString().substr(0, 10) === tide.date;

        function express(tide, now) {
            if (sameDay(tide, now)) {
                return `There's a ${tide.height} metre low at ${tide.time12}.`
             } else {
                return `There's a ${tide.height} metre low at ${tide.time12} on ${tide.dow}.`
            }
        }

        db.collection('tide-times')
          .where('instant', '>=', nowUtc)
          .where('highOrLow', '=', 'low')
          .orderBy('instant', 'asc')
          .limit(1)
          .get().then((snapshot) => {
            if (snapshot._size === 0) {
                console.log('No tides', nowUtc);
                sendResponse('Sorry, I can\'t find any tide times.');
            } else {
                snapshot.forEach((doc) => {
                    var tide = doc.data();
                    var replyText = express(tide, now);
                    sendResponse(replyText);
                });
            }
        })
        .catch((err) => {
            console.log('Error getting documents', err);
            sendResponse('Sorry, something went wrong. Maybe try again later.');  
        });

    },
    // Default handler for unknown or undefined actions
    'default': () => {
      let responseToUser = {
        //fulfillmentMessages: richResponsesV2, // Optional, uncomment to enable
        //outputContexts: [{ 'name': `${session}/contexts/weather`, 'lifespanCount': 2, 'parameters': {'city': 'Rome'} }], // Optional, uncomment to enable
        fulfillmentText: 'Sorry, I didn\'t understand that. You can ask for the next low tide.' // displayed response
      };
      sendResponse(responseToUser);
    }
  };
  // If undefined or unknown action use the default handler
  if (!actionHandlers[action]) {
    action = 'default';
  }
  // Run the proper handler function to handle the request from Dialogflow
  actionHandlers[action]();
  // Function to send correctly formatted responses to Dialogflow which are then sent to the user
  function sendResponse (responseToUser) {
    // if the response is a string send it as a response to the user
    if (typeof responseToUser === 'string') {
        let responseJson = {fulfillmentText: responseToUser}; // displayed response
        console.log('Text Response to Dialogflow: ' + JSON.stringify(responseJson));
        response.json(responseJson); // Send response to Dialogflow
    } else {
      // If the response to the user includes rich responses or contexts send them to Dialogflow
      let responseJson = {};
      // Define the text response
      responseJson.fulfillmentText = responseToUser.fulfillmentText;
      // Optional: add rich messages for integrations (https://dialogflow.com/docs/rich-messages)
      if (responseToUser.fulfillmentMessages) {
        responseJson.fulfillmentMessages = responseToUser.fulfillmentMessages;
      }
      // Optional: add contexts (https://dialogflow.com/docs/contexts)
      if (responseToUser.outputContexts) {
        responseJson.outputContexts = responseToUser.outputContexts;
      }
      // Send the response to Dialogflow
      console.log('Response to Dialogflow: ' + JSON.stringify(responseJson));
      response.json(responseJson);
    }
  }
}