--- Tic-tac-toe is a paper-and-pencil game for two players who take turns marking the spaces
--- in a three-by-three grid with X or O.
--- The player who succeeds in placing three of their marks in a horizontal, vertical, or
--- diagonal row is the winner. It is a solved game, with a forced draw assuming best play from both players.
--- The module Logic.Game contains the game logic.
module CLI.TicTacToe;

import Stdlib.Prelude open;
import Logic.Game open;

--- A ;String; that prompts the user for their input
prompt (x : GameState) : String :=
  "\n"
    ++str showGameState x
    ++str "\nPlayer "
    ++str showSymbol (player x)
    ++str ": ";

nextMove (s : GameState) : String → GameState :=
  stringToNat >> validMove >> flip playMove s;

--- Main loop
terminating
run : GameState → IO
  | (state b p (terminate msg)) :=
    printStringLn
      ("\n" ++str showGameState (state b p noError) ++str "\n" ++str msg)
  | (state b p (continue msg)) :=
    printString (msg ++str prompt (state b p noError))
      >>> readLn (run << nextMove (state b p noError))
  | x := printString (prompt x) >>> readLn (run << nextMove x);

--- The welcome message
welcome : String :=
  "MiniTicTacToe\n-------------\n\nType a number then ENTER to make a move";

--- The entry point of the program
main : IO := printStringLn welcome >>> run beginState;