add bulls and cows game

src/app.js

@@ -1,3 +1,43 @@
+/* eslint-disable no-console */
 'use strict';
 
-// Write your code here
+const readline = require('node:readline');
+
+const { generateRandomNumber } = require('./modules/generateRandomNumber');
+const { checkIsValidUserInput } = require('./modules/checkIsValidUserInput');
+const { getBullsAndCows } = require('./modules/getBullsAndCows');
+
+const randomNum = generateRandomNumber();
+
+console.log('Random number:', randomNum);
+askQuestion(randomNum);
+
+function askQuestion(randomNumber) {
+  const rl = readline.createInterface({
+    input: process.stdin,
+    output: process.stdout,
+  });
+
+  const promptUser = () => {
+    rl.question('Guess the number:\n', (userNumber) => {
+      if (checkIsValidUserInput(userNumber)) {
+        const userTry = getBullsAndCows(userNumber, randomNumber);
+
+        console.log(userTry);
+
+        if (userTry.bulls === 4) {
+          console.log('You win!');
+          rl.close();
+        } else {
+          console.log('Try again');
+          promptUser();
+        }
+      } else {
+        console.log('Number should include 4 unique digits from 1 to 9');
+        promptUser();
+      }
+    });
+  };
+
+  promptUser();
+}

src/modules/checkIsValidUserInput.js

@@ -9,7 +9,25 @@
  * @return {boolean} - True if the user input is valid, false otherwise
  */
 function checkIsValidUserInput(userInput) {
-  /* Write your code here */
+  if (userInput.startsWith('0')) {
+    return false;
+  }
+
+  if (userInput.length !== 4) {
+    return false;
+  }
+
+  if (Number.isNaN(Number(userInput))) {
+    return false;
+  }
+
+  for (let i = 0; i < 3; i++) {
+    if (userInput.includes(userInput[i], i + 1)) {
+      return false;
+    }
+  }
+
+  return true;
 }
 
 module.exports = {

src/modules/generateRandomNumber.js

@@ -7,7 +7,19 @@
  * @return {number} A random 4-digit number
  */
 function generateRandomNumber() {
-  /* Write your code here */
+  const digits = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+  const availableDigits = [...digits];
+  let number = '';
+
+  for (let i = 0; i < 4; i++) {
+    const randomIndex = Math.floor(Math.random() * availableDigits.length);
+    const randomDigit = availableDigits[randomIndex];
+
+    number = number.concat(randomDigit);
+    availableDigits.splice(randomIndex, 1);
+  }
+
+  return Number(number);
 }
 
 module.exports = {

src/modules/getBullsAndCows.js

@@ -13,7 +13,25 @@
  * Example: { bulls: 1, cows: 2 }
  */
 function getBullsAndCows(userInput, numberToGuess) {
-  /* Write your code here */
+  let bulls = 0;
+  let cows = 0;
+
+  const userNumbers = Array.from(String(userInput), (num) => +num);
+  const gameNumbers = Array.from(String(numberToGuess), (num) => +num);
+
+  gameNumbers.forEach((n, ind) => {
+    if (n === userNumbers[ind]) {
+      bulls += 1;
+    }
+  });
+
+  gameNumbers.forEach((n, ind) => {
+    if (userNumbers.includes(n) && ind !== userNumbers.indexOf(n)) {
+      cows += 1;
+    }
+  });
+
+  return { bulls, cows };
 }
 
 module.exports = {