var express = require("express");
var request = require("request");
var bodyParser = require("body-parser");
var controller = require('./controller');

var app = express();
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());
app.listen((process.env.PORT || 5000));

// Server index page
app.get("/", function (req, res) {
  res.send("Deployed!");
});

// Facebook Webhook
// Used for verification
app.get("/webhook", function (req, res) {
  if (req.query["hub.verify_token"] === process.env.VERIFICATION_TOKEN) {
    console.log("Verified webhook");
    res.status(200).send(req.query["hub.challenge"]);
  } else {
    console.error("Verification failed. The tokens do not match.");
    res.sendStatus(403);
  }
});


// Creates the endpoint for our webhook
app.post('/webhook', (req, res) => {

  let body = req.body;

  if (body.object === 'page') {

    // Iterates over each entry - there may be multiple if batched
    body.entry.forEach(function(entry) {

      // Gets the message. entry.messaging is an array, but
      // will only ever contain one message, so we get index 0
      let webhook_event = entry.messaging[0];
      console.log(webhook_event);

      // Get the sender PSID
      let sender_psid = webhook_event.sender.id;
      console.log('Sender PSID: ' + sender_psid);
      

      // Check if the event is a message or postback and
      // pass the event to the appropriate handler function
      if (webhook_event.message) {
        controller.handleMessage(sender_psid, webhook_event.message);
      } else if (webhook_event.postback) {
        controller.handlePostback(sender_psid, webhook_event.postback);
      }
    });

    // Returns a '200 OK' response to all requests
    res.status(200).send('EVENT_RECEIVED');
  } else {
    // Returns a '404 Not Found' if event is ninteliot from a page subscription
    res.sendStatus(404);
  }
});