server.js

const fox = require('fox-js'); // Some custom functions etc

const low = require('lowdb') // Database
const FileSync = require('lowdb/adapters/FileSync')

const path = require('path'),
      express = require('express'),
      app = express(),   
      Twit = require('twit'),
      config = {     
        twitter: {
          consumer_key:         process.env.CONSUMER_KEY,
          consumer_secret:      process.env.CONSUMER_SECRET,
          access_token:         process.env.ACCESS_TOKEN,
          access_token_secret:  process.env.ACCESS_TOKEN_SECRET,
          timeout_ms:           60*1000,
        }
      },
      T = new Twit(config.twitter);

// Setting up the lowdb local database
const adapter = new FileSync('.data/db.json');
const db = low(adapter);

// Uncomment to immediately clear the database
// dropEntireDatabase();

// A few constants and/or variables
const currentUser = process.env.USERNAME;
const targets = require('./targets.json').targets;

// Set DB defaults
db.defaults({ posted: [] })
  .write();

// Changable options
let mute = true;


// Things to run when script loads
init();



// Serve the public directory directly
app.use(express.static('public'));

// Triggered by uptime robot
app.all("/" + process.env.BOT_ENDPOINT, function (request, response) {
  console.log("The bot has been triggered!!!");
  
  runTriggerLoop();
  
  response.sendStatus(200);
}); // app.all Express call


app.all("/test", function (request, response) {
  console.log("The bot has been triggered!!!");
  
  runTestLoop();
  
  response.sendStatus(200);
}); // app.all Express call





var listener = app.listen(process.env.PORT, function () {
  console.log('Your bot is running on port ' + listener.address().port);
});



// Get the difference between two arrays
Array.prototype.diff = function(a) {
    return this.filter(function(i) {return a.indexOf(i) < 0;});
};

// test

function init() {
  checkTargetInDb(targets);
}


function checkTargetInDb(targets) {
  targets.forEach(user => {
    let userInDb = db.has(user).value();
    console.log("Checking if " + user + " is in the database...", userInDb);
    if (userInDb) return;
    // If user not in DB try to set them up after a delay
    setTimeout(() => {
      setupNewTargets(user);
    }, 5000)
  });
}


// Function to drop the database for testing (be careful)
function dropEntireDatabase() {
  const newState = {}
  db.setState(newState)
  db.write()
}



async function setupNewTargets (userName) {
  console.log('Setting up ' + userName + " in the database...");
  
  let favesRaw = await getRawFaves(userName);
  let favesExtracted = favesRaw.map(elem => {
    return elem.id_str + "," + elem.user.screen_name
  });
  
  db.set(userName, favesExtracted)
    .write();
}


// Some async await functions to try
async function getRawFaves(username) {
  var faves = await T.get('favorites/list', { screen_name: username })
    .catch(function (err) {
      console.log('Caught error:', err.stack)
    });
  return faves.data;
}

async function getExtractedFaves(username) {
  let favesExtracted = extractFaves(await getRawFaves(username));
  return favesExtracted;
}

function extractFaves(rawFaves) {
  return rawFaves.map(elem => {
    return elem.id_str + "," + elem.user.screen_name
  });
}

function storeTweetID(tweetID, screenName) {
  db.get("posted")
    .push(tweetID + "," + screenName)
    .write();
  console.log('wrote tweetID and screenName to db');
}

function isAlreadyTweeted(tweetID, screenName) {
  let postedTweets = db.get("posted").value();
  
  console.log("Checking database of:", postedTweets);
  console.log("For: " + tweetID + "," + screenName);
  
  if (postedTweets.indexOf(tweetID + "," + screenName) > -1) return true;
  else return false;
}

// Test loop
function runTestLoop() {
  
  // db.get("posted")
  //   .push("586374546615218177,swm0904")
  //   .write();
  // let posted = db.get("posted")
    // .find("586374546615218177,swm0904")
    // .value();
  
  // console.log(posted);
  
  // db.unset('posted')
  // .write()
  
  storeTweetID("874724911704489984","samanthamaiden");
  
  console.log(isAlreadyTweeted("874724911704489984","samanthamaiden"));
}

/*
 * THE MAIN LOOP
 *--------------------------------------*/

// This gets processed every 25 minutes
function runTriggerLoop() {
  console.log("Checking all targets for new faves...")

  
  targets.forEach(async target => {
    // Connect to Twitter and grab the faves
    let currentFaves = await getExtractedFaves(target);

    // Get stored faves from the time before
    let previouslyFaved = db.get(target).value() || [];

    // See if there are any new faves by minusing the old ones
    let newFaves = currentFaves.diff(previouslyFaved);
  
    console.log(newFaves); 
    
    // Tweet any new faves
    newFaves.forEach(async commaSeparatedFav => {
      
      // Split up our string of values to we can parse them
      let faves = commaSeparatedFav.split(",");
      
      // Check for already tweeted tweet otherwise return without processing
      if (isAlreadyTweeted(faves[0], faves[1])) {
        console.log("Found already tweeted tweet. Not continuing...")
        return;
      }
      
      // WONT PROCESS BELOW HERE IF ALREADY TWEETED THIS TWEET
      //----------------------------------------------------------------------------
      
      console.log('Tweeting faved tweet...')
      let response = await T.post('statuses/update', 
             { status: target + ' liked this tweet: ' + "https://twitter.com/" + faves[1] + "/status/" + faves[0] })
      .catch(function (err) {
        console.log('Caught error:', err.stack)
      });
      
      console.log('Tweeting finished!');
      
      console.log('Storing tweet ID...')
      
      // Store the tweet to avoid double posting
      storeTweetID(faves[0], faves[1]);
    });
    
    // Write current faves to database ready for next check
    db.set(target, currentFaves)
      .write();
  });
}

/*
 * Test loop
 */