package logikujo.atuin.FunctionalSamples

import scalaz._
import Scalaz._
import scalaz.effects._

object App {
  def main(args: Array[String]):Unit = Palindrome.run
}

object Palindrome {
  def run:Unit = loop().unsafePerformIO

  def loop(a:Unit):IO[Unit] =
    showBanner >>=| readLn >>= palindrome >>= showResult >>= loop

  def showBanner:IO[Unit] = for {
    _ <- putStrLn("Little example to test if a line is a palindrome:")
    _ <- putStrLn("Enter a line:?")
  } yield ()

  def palindrome(s:String):IO[Option[Boolean]] = 
    io{(s != "quit") option ((s.reverse == s) ?? true)}

  def showResult(o:Option[Boolean]):IO[Unit] =
    o.some(_ ? (putStrLn("Is a palindrome!")) |
        (putStrLn("Is NOT a palindrome :(, try it again!"))).none(io{System.exit(0)})
}