1. Changed app.js to acquire better skeletal code to start from. 2. Changed .git…

…ignore to exclude directory .idea/

 node_modules
+.idea/
\ No newline at end of file

-var express = require("express");
-var request = require("request");
-var bodyParser = require("body-parser");
+'use strict';
+let express = require("express"),
+    bodyParser= require("body-parser"),
+    app = express(),
+    request = require('request'),
+    config = require('config'),
+    images = require("./pics");
 
-var app = express();
-app.use(bodyParser.urlencoded({extended: false}));
+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!");
-});
+let users = {};
 
-// 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);
+app.listen(process.env.PORT || 8989, () => console.log('Example app listening on por 8989!'));
+
+app.get('/', (req, res) => res.send('Hello World!'));
+
+
+// Adds support for GET requests to our webhook
+app.get('/webhook', (req, res) => {
+
+  // Your verify token, Should be a random string.
+  let VERIFY_TOKEN = "2016104171";
+
+  // Parse the query params
+  let mode = req.query['hub.mode'];
+  let token = req.query['hub.verify_token'];
+  let challenge = req.query['hub.challenge'];
+
+
+  // Checks if a token and mode is in the query string of the request
+  if(mode && token) {
+
+    // Checks the mode and token sent is correcct
+    if (mode === 'subscribe' && token === VERIFY_TOKEN) {
+
+      // Responds with the challenge token from the request
+      console.log('WEBHOOK_VERIFIED');
+      res.status(200).send(challenge);
+
+    } else {
+      // Responds with '403 Forbidden' if verify tokens do not match
+      res.sendStatus(403);
+    }
   }
 });
 
-// All callbacks for Messenger will be POST-ed here
-app.post("/webhook", function (req, res) {
-  // Make sure this is a page subscription
-  if (req.body.object == "page") {
-    // Iterate over each entry
-    // There may be multiple entries if batched
-    req.body.entry.forEach(function(entry) {
-      // Iterate over each messaging event
-      entry.messaging.forEach(function(event) {
-        if (event.postback) {
-          processPostback(event);
-        }
-      });
+// 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) {
+        handleMessage(sender_psid, webhook_event.message);
+      } else if (webhook_event.postback) {
+        handlePostback(sender_psid, webhook_event.postback);
+      }
     });
 
-    res.sendStatus(200);
+    // Returns a '200 OK' response to all requests
+    res.status(200).send('EVENT_RECEIVED');
+  } else {
+    // Returns a '404 Not Found' if event is not from a page subscription
+    res.sendStatus(404);
   }
+
 });
 
-function processPostback(event) {
-  var senderId = event.sender.id;
-  var payload = event.postback.payload;
-
-  if (payload === "Greeting") {
-    // Get user's first name from the User Profile API
-    // and include it in the greeting
-    request({
-      url: "https://graph.facebook.com/v2.6/" + senderId,
-      qs: {
-        access_token: process.env.PAGE_ACCESS_TOKEN,
-        fields: "first_name"
-      },
-      method: "GET"
-    }, function(error, response, body) {
-      var greeting = "";
-      if (error) {
-        console.log("Error getting user's name: " +  error);
-      } else {
-        var bodyObj = JSON.parse(body);
-        name = bodyObj.first_name;
-        greeting = "Hi " + name + ". ";
-      }
-      var message = greeting + "My name is SP Movie Bot. I can tell you various details regarding movies. What movie would you like to know about?";
-      sendMessage(senderId, {text: message});
+// Views - handle Message, handle Postback
+
+// Handles message events
+const handleMessage = (sender_psid, received_message) => {
+  let response;
+
+  if(received_message.text){
+
+    // Create the payload for a basic text message
+    response = askTemplate()
+  }
+
+  // Sends the reponse message
+  callSendAPI(sender_psid, response;
+}
+
+const handlePostback = (sender_psid, received_postback) => {
+  let response;
+
+  // Get the payload for the postback
+  let payload = received_postback.payload;
+
+  // Set the response based on the postback payload
+  if (payload === 'CAT_PICS') {
+    response = imageTemplate('cats', sender_psid);
+    callSendAPI(sender_psid, response, function(){
+      callSendAPI(sender_psid, askTemplate('Show me more'));
     });
+  } else if (payload === 'DOG_PICS') {
+    response = imageTemplate('dogs', sender_psid);
+    callSendAPI(sender_psid, response, function(){
+      callSendAPI(sender_psid, askTemplate('Show me more'));
+    });
+  } else if(payload === 'GET_STARTED'){
+    response = askTemplate('Are you a Cat or Dog Person?');
+    callSendAPI(sender_psid, response);
   }
+  // Send the message to acknowledge the postback
 }
 
-// sends message to user
-function sendMessage(recipientId, message) {
-  request({
-    url: "https://graph.facebook.com/v2.6/me/messages",
-    qs: {access_token: process.env.PAGE_ACCESS_TOKEN},
-    method: "POST",
-    json: {
-      recipient: {id: recipientId},
-      message: message,
+const askTemplate = (text) => {
+  return {
+    "attachment":{
+      "type":"template",
+      "payload":{
+        "template_type":"button",
+        "text": text,
+        "buttons":[
+          {
+            "type":"postback",
+            "title":"Cats",
+            "payload":"CAT_PICS"
+          },
+          {
+            "type":"postback",
+            "title":"Dogs",
+            "payload":"DOG_PICS"
+          }
+        ]
+      }
     }
-  }, function(error, response, body) {
-    if (error) {
-      console.log("Error sending message: " + response.error);
+  }
+}
+
+// Sends response messages via the Send API
+const callSendAPI = (sender_psid, response, cb = null) => {
+  // Construct the message body
+  let request_body = {
+    "recipient": {
+      "id": sender_psid
+    },
+    "message": response
+  };
+
+  // Send the HTTP request to the Messenger Platform
+  request({
+    "uri": "https://graph.facebook.com/v2.6/me/messages",
+    "qs": { "access_token": config.get('facebook.page.access_token') },
+    "method": "POST",
+    "json": request_body
+  }, (err, res, body) => {
+    if (!err) {
+      if(cb){
+        cb();
+      }
+    } else {
+      console.error("Unable to send message:" + err);
     }
   });
 }
+
+const imageTemplate= (type, sender_id) => {
+  return {
+    "attachment":{
+      "type":"image",
+      "payload":{
+        "url": getImage(type, sender_id),
+        "is_reusable":true
+      }
+    }
+  }
+}
+
+let users = {};
+
+const getImage= (type, sender_id) => {
+  // create user if doesn't exist
+  if(users[sender_id] === undefined){
+    users = Object.assign({
+      [sender_id] : {
+        'cats_count' : 0,
+        'dogs_count' : 0
+      }
+    }, users);
+  }
+
+  let count = images[type].length, // total available images by type
+      user = users[sender_id], // // user requesting image
+      user_type_count = user[type+'_count'];
+
+
+  // update user before returning image
+  let updated_user = {
+    [sender_id] : Object.assign(user, {
+      [type+'_count'] : count === user_type_count + 1 ? 0 : user_type_count + 1
+    })
+  };
+  // update users
+  users = Object.assign(users, updated_user);
+
+  console.log(users);
+  return images[type][user_type_count];
+}