package playground

import scala.annotation.tailrec
import scala.io.StdIn
import scala.util.Random

trait Action {
  def actionType(): String
}

case class GuessAction(wasRight: Boolean, result: String) extends Action {
  override def actionType(): String = "GUESS"
}

case class GameState(tries: Int, wins: Int, lastResult: String, continue: Boolean = true)

object GameState {
  def update(state: GameState, action: Action): GameState = action match {
    case GuessAction(true, result) => state.copy(tries = state.tries + 1, wins = state.wins + 1, lastResult = result)
    case GuessAction(false, result) => state.copy(tries = state.tries + 1, lastResult = result)
    case _ => state
  }
}

object PlayerInteraction {

  def inputOption(): String = StdIn.readLine.toUpperCase
}

object GameInterface {

  def showPrompt() = print("\n(h)eads, (t)ails or (q)quit? ")
  def showState(state: GameState) = println(s"tries: ${state.tries}, wins: ${state.wins}")
  def showAttemptResult(wasRight: Boolean) =
    if(wasRight) println("Yes! You guessed it!")
    else println("Sorry! You're wrong")

  def showGameOver(state: GameState) = {
    println("================")
    println("Game Over")
    println("================")
  }
}

object Game extends App {

  def start = gameLoop(GameState(0, 0, "", true), Random)

  @tailrec
  def gameLoop(state: GameState, random: Random): Unit = {
    // Shows the prompt
    GameInterface.showPrompt()

    // get user input (heads, tails or quit)
    val userOption = PlayerInteraction.inputOption()

    // Check user input
    userOption match {
      case "H" | "T" => {
        val side = flipCoin(random.nextInt(2))
        val rightGuess = isGuessRight(userOption, side)

        val action =
          if(rightGuess) new GuessAction(true, side)
          else new GuessAction(false, side)

        val nextState = GameState.update(state, action)

        guessResult(nextState, rightGuess)
        gameLoop(nextState, random)
      }
      case "Q" => endGame(state)
      case _ => gameLoop(state, random)
    }
  }

  def isGuessRight(playerGuess: String, side: String) =
    playerGuess == side

  def guessResult(state: GameState, wasRight: Boolean) = {
    GameInterface.showAttemptResult(wasRight)
    GameInterface.showState(state)
  }

  def endGame(state: GameState) = {
    GameInterface.showGameOver(state)
    GameInterface.showState(state)
  }

  def flipCoin(value: Int): String = value match {
    case 0 => "H"
    case 1 => "T"
    case _ => "?"
  }

  Game.start
}