/**
* [1,2,[3,4]] -> [1,2,3,4]
*/
let arr = [1,2,[3,4, [5,6, [7, [8, 9, 10]]]]]
function flatten(arr) {
  return arr.reduce(function(acc, next){
    let isArray =  Array.isArray(next)
    return acc.concat(isArray ? flatten(next) : next)
  }, [])
}
if (!Array.prototype.flatten) {
  Array.prototype.flatten = function() {
    return flatten(this)
  }
}
console.log(arr.flatten());

class CustomPromise {
  state = "PENDING"
  value = undefined
  thenCallbacks = []
  errorCallbacks = []
  constructor(action) {
    action(this.resolver.bind(this), this.reject.bind(this))
  }
  resolver(value) {
    this.state = "RESOLVED"
    this.value = value
    this.thenCallbacks.forEach((callback) => {
      callback(this.value)
    })
  }
  reject(value) {
    this.state = "REJECTED"
    this.value = value
    this.errorCallbacks.forEach((callback) => {
      callback(this.value)
    })
  }
  then(callback) {
    this.thenCallbacks.push(callback)
    return this
  }
  catch (callback) {
    this.errorCallbacks.push(callback)
    return this
  }
}
let promise = new CustomPromise((resolver, reject) => {
  setTimeout(() => {
    const rand = Math.ceil(Math.random(1 * 1 + 6) * 6)
    if (rand > 2) {
      resolver("Success")
    } else {
      reject("Error")
    }
  }, 1000)
})
promise
  .then(function(response){
    console.log(response)
  })
  .catch(function(error){
    console.log(error)
  })

// O(M)
function getMovies() {
  return []; // [{id, name, year}]
}
// O(R)
function getRatings() {
  return []; // [{id, movie_id, rating}]   0 <= rating <= 10   // e.g 9.3
}
/**
* minAvgRating ->
*    avgRating >= minAvgRating
*
* sort ->
*    name -> ascending order movies by name
*   -name -> descending
*
*    avgRating
*
*
* search ->
*   'ave' -> 'Avengers'
*   'avengers' -> 'Avengers'
*   'AvengersInfinitywar' -> 'Avengers'
*/
const toLower = str => str.toLocaleLowerCase()
const getAvrgRating = (movie, movingWithRatings) => {
  let count = 0;
  return movingWithRatings.reduce((acc, value, index) => {
    const movieMatch = movie.id === value.movie_id
    if (movieMatch) {
      acc+=value.rating
      count++
    }
    if (index === movingWithRatings.length - 1) {
      acc = acc/count
    }
    return acc
  }, 0)
}
const isSubString = (str1, str2) => {
  str1 = toLower(str1.split(" ").join(""))
  str2 = toLower(str2.split(" ").join(""))
  if (str1.length > str2.length) {
    return str1.startWith(str2)
  } else {
    return str2.startWith(str1)
  }
}
const moviesList = getMovies()
const movingWithRatings = getRatings();
function queryMovies({ search, sort, minAvgRating }) {
  let filteredMovies = movingWithRatings.filter(movie => getAvrgRating(movie, movingWithRatings) >= minAvgRating);
  filteredMovies = filteredMovies.map(movie => moviesList.filter(listItem => listItem.id === movie.movie_id).pop())
  filteredMovies = filteredMovies.filter(movie => isSubString(toLower(movie.name), toLower(search)))
  filteredMovies = filteredMovies.sort((a, b) => {
    const isDescending = sort[0] === '-' ? true : false
    let sortCopy = isDescending ? sort.slice(1) : sort
    const value1 = a[sortCopy]
    const value2 = b[sortCopy]
    if (isDescending) {
      return value1 > value2 ? -1 : 1
    }else {
      return value1 < value2 ? -1 : 1
    }
  })
  filteredMovies = filteredMovies.map(movie => ({
    ...movie,
    avgRating: movingWithRatings.filter(ratedMovie => ratedMovie.movie_id === movie.id)[0].rating
  }))
  return filteredMovies
}

//service.js
const POSTS_URL = `https://jsonplaceholder.typicode.com/posts`;
const COMMENTS_URL = `https://jsonplaceholder.typicode.com/comments`;
export const fetchAllPosts = () => {
  return fetch(POSTS_URL).then(res => res.json());
};
export const fetchAllComments = () => {
  return fetch(COMMENTS_URL).then(res => res.json());
};
import { fetchAllPosts, fetchAllComments } from "./service";
const fetchData = async () => {
  const [posts, comments] = await Promise.all([
    fetchAllPosts(),
    fetchAllComments()
  ]);
  const grabAllCommentsForPost = postId =>
    comments.filter(comment => comment.postId === postId);
  const mappedPostWithComment = posts.reduce((acc, post) => {
    const allComments = grabAllCommentsForPost(post.id);
    acc[post.id] = allComments;
    return acc;
  }, {});
  console.log("mappedPostWithComment ", mappedPostWithComment);
};
fetchData();

let s1 = "sample"
if (!String.prototype.getHashCode) {
  String.prototype.getHashCode = function(){
    console.log('String instance ', this)
    return this
  }
}

1+true
    true+true
    ‘1’+true
    ‘2’ > ’3’
    ‘two’>’three’

2
2
1true
false
true

//bind
if (!Function.prototype.bind) {
  Function.prototype.bind = function(...arg){
    const func = this
    const context = arg[0]
    const params = arg.slice(1)
    return function(...innerParam) {
      func.apply(context, [...params, ...innerParam])
    }
  }
}
//reduce
Array.prototype.reduce = function(func, initState) {
  const arr = this
  const callback = func
  let init = initState
  arr.forEach(function(value, index){
      init=callback(init, value)
  })
  return init
}

const debounce = function(func, interval) {
  let timerId;
  return function(e){
    clearTimeout(timerId)
    timerId = setTimeout(function(){
      func.apply()
    }, interval)
  }
}
debounce(apiCall, 3000)

const throttle = (callback, interval) => {
  let timerId;
  let allowEvents = true;
  return function() {
    let context = this;
    let args = arguments;
    if (allowEvents) {
      callback.apply(context, args)
      allowEvents = false;
      timerId = setTimeOut(function(){
        allowEvents = true
      }, interval)
    }
  }
}

//С использованием метода setInterval, декоратора throttle и флагов
setInterval=>Endpoint=>Render
//с инверсией управления
//Endpoint=>Render=>setTimeout=>Endpoint=>Render=>SetTimeout...

class Parent(name){
  constructor(name) {
    this.name=name
  }
  getName(){return this.name}
}
class Children extends Parent {
  constructor(props){
    super(props)
  }
}

function Parent(name) {
  this.name = name
}
Parent.prototype.getName = function() {
  return this.name
}
function Children(name){
  Parent.call(this, name)
}
Children.prototype = new Parent()

//Q.1
var x = 1;
var y = x;
x = 0;
console.log(x, y);
//Q.2
var x = [1];
var y = x;
x = [];
console.log(x,y);
//Q.3
function Abc() { console.log(this); };
Abc()
new Abc();
//Q.4
var x = 1;
var obj = {
  x: 2,
  getX: function () {
    return console.log(this.x);
  }
};
obj.getX()
let a = obj.getX
console.log(a)
//Q.5
//Как вывести 2 с использованием переменной a в коде из предыдущего вопроса?
//Q.6
console.log("A");
setTimeout(() => console.log("B"), 0);
setTimeout(() => console.log("C"), 0);
console.log("D");
//Q.7
setTimeout(function() {
  console.log("A");
}, 0);
Promise.resolve().then(function() {
  console.log("B");
}).then(function() {
  console.log("C");
});
console.log("D");
//Q.8
let obj1 = {
  a:1,
  b:2
}
function mutate(obj) {
  obj = {a:4, c:6}
}
console.log(obj1)
mutate(obj1)
console.log(obj1)

//A.1
0 1
//A.2
[] [1]
//A.3
Будет выведен объект window
//A.4
Будут выведены значения 2 и 1
//A.5
a.call(obj);
//A.6
A, D, B , C
//A.7
D, B, C, A
//A.8
{ a: 1, b: 2 }
{ a: 1, b: 2 }

const list = [1,2,3,4,5,6,7,8]
const filteredArray = list.filter(between(3, 6)) // [4,5]

function between(start, end) {
  return function (value,index) {
    return value>start && value<end
  }
}

A := 1
B := A*2 + 2
C := B*2 + 3 и так далее...

//A = 1
//B = A*2 +2
//C = B*2+ 3
//D = C*2+ 3
var genCharArray = function(charA, charZ) {
    var a = [], i = charA.charCodeAt(0), j = charZ.charCodeAt(0);
    for (; i <= j; ++i) {
        a.push(String.fromCharCode(i));
    }
    return a;
}
var charMap = {};
var charArray = genCharArray('a', 'z');
charArray.forEach(function(char, index){
    charMap[char] = Number(index + 1);
});
var charSequence = function(char){
    if(typeof char==="string"){
        char = charMap[char];
    }
    if(char==1){
        return 1;
    }else{
        return char + 2 * charSequence(char-1);
    }
}
var input = process.argv[2];
if(input.length===1){
    console.log(charSequence(charMap[input]));
}else if(input.length>1){
    var charTotalSequence = input.split("").reduce(function(acc, curr){
        return acc + charSequence(charMap[curr]);
    },0);
    console.log(charTotalSequence);
}

let nums = [2, 7, 10, 1, 11, 15, 9]
let target = 11
let numsMap = new Map()
let pairs = nums.reduce((acc, num) => {
  let numToFind = target - num
  if (numsMap.get(numToFind)) {
    return [...acc, [num, numToFind]]
  } else {
    numsMap.set(num, true)
    return [...acc]
  }
}, [])
console.log("Pairs ", pairs)

let x = [1, 2, 3, 5, 4] //Результаты: 5
if x.length == 1 return x[0]
else
let i = 1
for(;i<x.length-1;i++){
  if x[i-1]<x[i] and x[i] > x[i+1] return x[i]
}
if x.length - 1 == i return x[i]

[
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
//Сначала транспонируем матрицу.
//После транспонирования матрица будет выглядеть так.
[
[1, 4, 7],
[2, 5, 8],
[3, 6, 9]
]
//Теперь остается всего лишь изменить порядок элементов массива на обратный.
//В результате матрица будет выглядеть так.
[
[7, 4, 1],
[8, 5, 2],
[9, 6, 3]
]
//Первоначальная матрица развернута на 90 градусов.

let x = [1, 2, 3, 4, 5]
let target = 7
let found = []
const twoPointer = (l ,r, current) => {
  while(l<r){
    const totalSum = current + x[l] + x[r]
    if (totalSum === target) {
      found.push([current, x[l], x[r]])
      return
    } else if (totalSum > target) {
      r--
    } else {
      l++
    }
  }
}
const threeSum = (x, target) => {
    for (let i=0;i<x.length;i++) {
      const current = x[i];
      let leftPointer = i+1
      let rightPointer = x.length - 1
      if (current+x[leftPointer]+x[rightPointer] === target) {
        found.push([current, x[leftPointer], x[rightPointer]])
      } else {
        twoPointer(leftPointer, rightPointer, current)
      }
  }
  return found
}

const subStrHasSameCharCount = (str, startIndex, endIndex, totalHop) => {
  let charMap = {}
  for (let k=startIndex;k<endIndex;k++) {
    let currentChar = str[k]
    if (charMap[currentChar]) {
      charMap[currentChar]++
    } else {
      charMap[currentChar] = 1
    }
  }
  let totalCount = Object.values(charMap).length > 0
  return totalCount ? Object.values(charMap).every(item => item == totalHop) : false
}
const characterWithCountK = (str, k) => {
  if (k == 0) return ''
  let count = 0
  let initialHop = k
  while (initialHop < str.length) {
    for (let j=0;j<str.length;j++) {
      let startIndex = j
      let endIndex = j + initialHop
      if(endIndex > str.length) continue
      count = subStrHasSameCharCount(str, startIndex, endIndex, k)
        ? count + 1: count
    }
    initialHop+=k
  }
  count = subStrHasSameCharCount(str, 0, initialHop, k)
        ? count + 1: count
  return count
}
let str = 'aabbcc'
let k = 2
console.log(characterWithCountK(str, k))

let s1 = 'dadbcbc'
let s2 = 'ccbbdad'
let charMap = {}
const canBeRearranged = (s1, s2) => {
  if(s1.length!==s2.length){
    return false
  }
  for(let i=0;i<s1.length;i++){
    const charFromString1 = s1[i]
    const charFromString2 = s2[i]
    if(charFromString1 in charMap){
      charMap[charFromString1]++
    } else {
      charMap[charFromString1] = 1
    }
    if(charFromString2 in charMap){
      charMap[charFromString2]--
    } else {
      charMap[charFromString2] = -1
    }
  }
  for(let x in charMap){
    if (charMap[x]!==0){
      return false
    }
  }
  return true
}
canBeRearranged(s1, s2)

const swap = (index1, index2, arr) => {
  let temp = arr[index1]
  arr[index1] = arr[index2]
  arr[index2] = temp
}
const shuffle = (arr) => {
  let totalLength = arr.length
  while(totalLength > 0) {
    let random = Math.floor(Math.random() * totalLength)
    totalLength--
    swap(totalLength, random, arr)
  }
  return arr
}
let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
arr = shuffle(arr)

let arr = [4, 5, 7, 8, [5, 7, 9, [3, 5, 7]]]
let sum = 0
const calculateSum = (arr) => {
  arr.reduce(function(acc, currentVal) {
    const isEntryArray = Array.isArray(currentVal)
    if (isEntryArray) {
      return acc.concat(calculateSum(currentVal))
    } else {
      sum+=currentVal
      return acc.concat(currentVal)
    }
  }, [])
}
calculateSum(arr)
console.log(sum)

const obj = {
  level1: {
    level2: {
      level3: {
        more: 'stuff',
        other: 'otherz',
        level4: {
          the: 'end',
        },
      },
    },
    level2still: {
      last: 'one',
    },
    am: 'bored',
  },
  more: 'what',
  ipsum: {
    lorem: 'latin',
  },
};
var removeNesting = function(obj, parent){
  for (let key in obj){
    if (typeof obj[key] === "object") {
      removeNesting(obj[key], parent+"."+key)
    } else {
      flattenedObj[parent+'.'+key] = obj[key]
    }
  }
}
let flattenedObj = {}
const sample = removeNesting(obj, "");
console.log(flattenedObj);

const employeesData = [{
  id: 2,
  name: 'Андрей (главный технический директор)',
  reportees: [6]
}, {
  id: 3,
  name: 'Алексей (главный операционный директор)',
  reportees: []
}, {
  id: 6,
  name: 'Александр (руководитель инженерной группы)',
  reportees: [9]
}, {
  id: 9,
  name: 'Анатолий (старший инженер)',
  reportees: []
}, {
  id: 10,
  name: 'Антон (генеральный директор)',
  reportees: [2, 3],
}];
/*
A (генеральный директор)
----B (главный технический директор)
--------D (руководитель инженерной группы)
------------E (старший инженер-разработчик)
----C (главный операционный директор)
*/
const findCeo = (currentEmp) => {
  let parentEmployee = employeesData.filter(emp => emp.reportees.indexOf(currentEmp.id) > -1)
  if (parentEmployee && parentEmployee.length > 0) {
    return findCeo(parentEmployee[0])
  } else {
    return currentEmp
  }
}
const logHierarchy = (currentEmp, indent) => {
  console.log("-".repeat(indent) + currentEmp.name)
  indent+=4;
  for(let i=0;i <currentEmp.reportees.length;i++) {
    let employee = employeesData.filter(emp => emp.id === currentEmp.reportees[i])
    logHierarchy(employee[0], indent)
  }
}
const traverse = (employee) => {
  let ceo = findCeo(employee)
  logHierarchy(ceo, 0)
}
traverse(employeesData[0])

const inputMatrix = [
  [1, 2, 3, 4,  5],
  [6, 7, 8, 9, 10],
  [11,12,13,14,15],
  [16,17,18,19,20],
]
const exprectOutput = [1,2,3,4,5,10,15,20,19,18,17,16,11,6,7,8,9,14,13,12]

function spiralParser(inputMatrix){
  const output = [];
  let rows = inputMatrix.length;
  let cols = rows > 0 ? inputMatrix[0].length : 0;
  //singleEmptyRow => Edge case 1 //[]
  if (rows === 0) {
    return []
  }
  if (rows === 1) {
    //singleElementRowNoCol => Edge case 2 //[[]]
    if (cols === 0) {
      return []
    } else if (cols === 1){
      //singleElementRow => Edge case 3 //[[1]]
      output.push(inputMatrix[0][0])
      return output
    }
  }
  let top = 0;
  let bottom = rows - 1;
  let left = 0;
  let right = cols - 1;
  let direction = 0;
  //0 => left->right
  //1 => top->bottom
  //2 => right->left
  //3 => bottom->top
  while(left <= right && top <= bottom) {
    if(direction === 0) {
      //left->right
      for (let i=left; i<=right;i++) {
        output.push(inputMatrix[top][i])
      }
      top++;
    } else if (direction === 1) {
      //top->bottom
      for (let i=top; i<=bottom;i++) {
        output.push(inputMatrix[i][right])
      }
      right--
    } else if (direction === 2) {
      //right->left
      for (let i=right; i>=left;i--) {
        output.push(inputMatrix[bottom][i])
      }
      bottom--
    } else if (direction === 3) {
      //bottom->top
      for (let i=bottom; i>=top;i--) {
        output.push(inputMatrix[i][left])
      }
      left++
    }
    direction = (direction + 1) % 4
  }
  return output;
}
console.log(spiralParser(inputMatrix2))

let str = 'bbbaaaaccadd'; //Больше последовательных вхождений (4) у символа a

//псевдокод
maxNow = если длина входной строки равна1 или больше 1 ? 1 : 0
maxOverall = если длина входной строки равна1 или больше 1 ? 1 : 0
для символов входной строки с индексом 1 и больше
  если символ равен предыдущему символу
    maxNow++ //увеличить на 1
    maxOverall = max(maxOverall, maxNow)
  иначе если символ не равен предыдущему символу
    maxNow = 1

let inputArr = [2,9,1,5,2,3,1,2,7,4,3,8,29,2,4,6,54,32,2,100]
//ouput => [9,1,5,3,1,7,4,3,8,29,4,6,54,32,100,2,2,2,2,2]

let slowRunner = 0
for (let fastRunner=0;fastRunner<arr.length;fastRunner++) {
  if (arr[fastRunner]!==2 && arr[slow] == 2) {
    [arr[fastRunner], arr[slow]] = [arr[slow], arr[fastRunner]]
    slowRunner++
  }
}

//На входе = 1 -> 2 -> 3 -> 4 -> 5 -> 6
//В результате = 1 <- 2 <- 3 <- 4 <- 5 <- 6

//псевдокод
let current = head
let prev = null
let next = null
while(current) {
  next = current.next
  current.next = prev
  prev = current
  current = next
}

//псевдокод
const preorder = (root) => {
  let stack = []
  stack.push(root)
  пока(переменная stack содержит данные) {
    let current = stack.pop()
    console.log(current.value)
    if (current.right) {
      stack.push(current.right)
    }
    if (current.left) {
      stack.push(current.left)
    }
  }
}

id: уникальный идентификатор
имя: имя пользователя
товары: список товаров, заказанных пользователем
адрес: адрес пользо
индекс: почтовый индекс пользователя