"use strict";

// get a random number between 1 and 20
const num = Math.ceil(Math.random() * 20);

// get the computer's guess
const computerGuess = Math.ceil(Math.random() * 20); 

// get the user's guess
const userGuess = parseInt(prompt("Enter a number between 1 and 20"));

if (isNaN(userGuess)) {
    alert("Not a valid number. Computer wins.")
} else if (userGuess < 1 || userGuess > 20) {
    alert("Not a number between 1 and 20. Computer wins.");
} else {
    let message = "The number is " + num + ".\n" +
        "You guessed " + userGuess + 
        " and the computer guessed " + computerGuess + ".\n";

    // compute the difference between the guesses and the number
    const computerDiff = Math.abs(num - computerGuess);
    const userDiff = Math.abs(num - userGuess);

    // determine the winner
    if (userDiff === computerDiff) {
        message += "It's a tie!";
    } else if (userDiff < computerDiff) {
        message += "You WIN!";
    } else {
        message += "Computer wins.";
    }
    
    alert(message);
}