const luhnCheck = num => {
  let arr = (num + '')
    .split('')
    .reverse()
    .map(x => parseInt(x));
  let lastDigit = arr.splice(0, 1)[0];
  let sum = arr.reduce(
    (acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val *= 2) > 9 ? val - 9 : val)),
    0
  );
  sum += lastDigit;
  return sum % 10 === 0;
};

luhnCheck('4485275742308327'); // true
luhnCheck(6011329933655299); //  true
luhnCheck(123456789); // false

const heapsort = arr => {
  const a = [...arr];
  let l = a.length;

  const heapify = (a, i) => {
    const left = 2 * i + 1;
    const right = 2 * i + 2;
    let max = i;
    if (left < l && a[left] > a[max]) max = left;
    if (right < l && a[right] > a[max]) max = right;
    if (max !== i) {
      [a[max], a[i]] = [a[i], a[max]];
      heapify(a, max);
    }
  };

  for (let i = Math.floor(l / 2); i >= 0; i -= 1) heapify(a, i);
  for (i = a.length - 1; i > 0; i--) {
    [a[0], a[i]] = [a[i], a[0]];
    l--;
    heapify(a, 0);
  }
  return a;
};

heapsort([6, 3, 4, 1]); // [1, 3, 4, 6]

const insertionSort = arr =>
  arr.reduce((acc, x) => {
    if (!acc.length) return [x];
    acc.some((y, j) => {
      if (x <= y) {
        acc.splice(j, 0, x);
        return true;
      }
      if (x > y && j === acc.length - 1) {
        acc.splice(j + 1, 0, x);
        return true;
      }
      return false;
    });
    return acc;
  }, []);
  
insertionSort([6, 3, 4, 1]); // [1, 3, 4, 6]

//Allegedly never tested on the twitter website
function scrapeScreen(){
    let articles = Array.from(document.getElementsByTagName("article"));
    let results = [];
    for(let tweet of articles){
        const isAnAd = Array.from(tweet.querySelectorAll("span")).map((e)=>e.textContent).includes("Ad");
        if(isAnAd){
            //console.log(tweet, "is an ad. Skipping...");
            continue;
        }
        const userName = tweet.querySelector("[data-testid='User-Name'] > div:nth-child(2) > div > div")?.textContent;
        const tweetContent = tweet.querySelector("[data-testid='tweetText']")?.textContent;
        const timeStamp = tweet.querySelector("time")?.getAttribute("datetime");
        const tweetLink = tweet.querySelector("time")?.parentElement?.getAttribute("href");
        if((!userName) || (!tweetContent)) continue;
        results.push({
            username: userName,
            tweetText: tweetContent,
            timeStamp: timeStamp,
            tweetLink: tweetLink
        });
    }
    return results;
}
let scraped = scrapeScreen();
setInterval(()=>{
    scraped = scraped.concat(
        scrapeScreen().filter((tweet)=>{
            for(let scrapedTweet of scraped){
                if(scrapedTweet.username == tweet.username && scrapedTweet.tweetText == tweet.tweetText) return false;
            }
            return true;
        })
    );
}, 500); //Scrape everything on the screen twice a second

window.scrollIntervalId = setInterval(function(){
    window.scrollBy(0, 1000);
}, 500); //Scroll for me


//http://bgrins.github.io/devtools-snippets/#console-save
(function(console){

console.save = function(data, filename){

 if(!data) {
 console.error('Console.save: No data')
 return;
 }

 if(!filename) filename = 'console.json'

 if(typeof data === "object"){
 data = JSON.stringify(data, undefined, '\t')
 }

 var blob = new Blob([data], {type: 'text/json'}),
 e = document.createEvent('MouseEvents'),
 a = document.createElement('a')

 a.download = filename
 a.href = window.URL.createObjectURL(blob)
 a.dataset.downloadurl = ['text/json', a.download, a.href].join(':')
 e.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null)
 a.dispatchEvent(e)
 }
})(console)

setTimeout(()=>{
    clearTimeout(window.scrollIntervalId);
    delete window.scrollIntervalId;

    console.save(scraped, "TwitterScrape" + Date.now() + ".json");
}, 60 * 1000 * 20); //Twenty minutes

// `date` is a `Date` object
const formatYmd = date => date.toISOString().slice(0, 10);

// Example
formatYmd(new Date());      // 2020-05-06

class DoublyLinkedList {
  constructor() {
    this.nodes = [];
  }

  get size() {
    return this.nodes.length;
  }

  get head() {
    return this.size ? this.nodes[0] : null;
  }

  get tail() {
    return this.size ? this.nodes[this.size - 1] : null;
  }

  insertAt(index, value) {
    const previousNode = this.nodes[index - 1] || null;
    const nextNode = this.nodes[index] || null;
    const node = { value, next: nextNode, previous: previousNode };

    if (previousNode) previousNode.next = node;
    if (nextNode) nextNode.previous = node;
    this.nodes.splice(index, 0, node);
  }

  insertFirst(value) {
    this.insertAt(0, value);
  }

  insertLast(value) {
    this.insertAt(this.size, value);
  }

  getAt(index) {
    return this.nodes[index];
  }

  removeAt(index) {
    const previousNode = this.nodes[index - 1] || null;
    const nextNode = this.nodes[index + 1] || null;

    if (previousNode) previousNode.next = nextNode;
    if (nextNode) nextNode.previous = previousNode;

    return this.nodes.splice(index, 1);
  }

  clear() {
    this.nodes = [];
  }

  reverse() {
    this.nodes = this.nodes.reduce((acc, { value }) => {
      const nextNode = acc[0] || null;
      const node = { value, next: nextNode, previous: null };
      if (nextNode) nextNode.previous = node;
      return [node, ...acc];
    }, []);
  }

  *[Symbol.iterator]() {
    yield* this.nodes;
  }
}

const list = new DoublyLinkedList();

list.insertFirst(1);
list.insertFirst(2);
list.insertFirst(3);
list.insertLast(4);
list.insertAt(3, 5);

list.size;                      // 5
list.head.value;                // 3
list.head.next.value;           // 2
list.tail.value;                // 4
list.tail.previous.value;       // 5
[...list.map(e => e.value)];    // [3, 2, 1, 5, 4]

list.removeAt(1);               // 2
list.getAt(1).value;            // 1
list.head.next.value;           // 1
[...list.map(e => e.value)];    // [3, 1, 5, 4]

list.reverse();
[...list.map(e => e.value)];    // [4, 5, 1, 3]

list.clear();
list.size;                      // 0