let readline = require('readline')
let rl = readline.createInterface(process.stdin, process.stdout)

function ageIsValid (x) {
  if ((parseInt(x) > 99) || isNaN(x)) {
    return false
  }
  else {
    return true
  }
}

function askBirthday (x) {
  rl.question(`Did you turn ${x} this year? (Y/N)\n -->  `, function (answer) {
    let currentYear = ((new Date()).getFullYear())
    if (answer === 'Y') {
      console.log('You were born in ' + (currentYear - x))
      rl.close()
    } else if (answer === 'N') {
      console.log('You were born in ' + (currentYear - x - 1))
      rl.close()
    } else {
      console.log('ERROR: Please respond with Y or N\n')
      askBirthday(x)
    }
  })
}

function ageApp () {
  rl.question('How old are you?\n -->  ', function (age) {
    if (ageIsValid(age)) {
      askBirthday(age)
    } else {
      console.log('ERROR: Enter a correct age.')
      ageApp()
    }
  })
}

console.log('<------ AGE APP <3 Made with love at the WCS-------->')
ageApp()