CLI Application (xo game)

../bin/xo

#!/usr/bin/env ruby

require_relative '../lib/xo'

puts "Lets play XO"
board = [" ", " ", " ", " ", " ", " ", " ", " ", " "]
play(board)

../lib/xo

# self-explanatory, prints arbitrary arrangements of the board
def display_board(board)
  puts " #{board[0]} | #{board[1]} | #{board[2]} "
  puts "-----------"
  puts " #{board[3]} | #{board[4]} | #{board[5]} "
  puts "-----------"
  puts " #{board[6]} | #{board[7]} | #{board[8]} "
end

# defines a constant with arrays for each win condition
win_conditions = [
  [0, 1, 2],
  [0, 3, 6],
  [0, 4, 8],
  [1, 4, 7],
  [2, 5, 8],
  [2, 4, 6],
  [3, 4, 5],
  [6, 7, 8],
]

def input_to_index(input)
# convert input to integer and subtract 1.
  input.to_i - 1
  # users count from 1, Ruby from 0
end

def move(board, index, symbol)
  board[index] = symbol
end

def position_taken?(board, index)
  if board[index] == " " || board[index] == "" || board[index] == nil # safety measures
      taken = false
    elsif board[index] == "X" || board[index] == "O"
      taken = true
  end
end

def valid_move?(board, index)
  index.between?(0,8) && !position_taken?(board, index)
   # if the position isnt taken and is on the board, move must be valid
end

def turn(board)
  puts "Please enter 1-9:"
    userInput = gets.strip # gets the user input and calls input_to_index
    index = input_to_index(userInput)
    if !valid_move?(board, index) # asks for input again after a failed validation
      turn(board)
    else # makes valid moves
      move(board, index, current_player(board))
    end
  display_board(board)
end


def turn_count(board)
  # counts occupied positions
  count = 0
  board.each do |index|
    if index != " "
      count += 1
    end
  end
    count
 end

def current_player(board)
  if turn_count(board) % 2 == 0
  # returns the correct player, X, for the first move
    return "X"
  else
    # O for the second move
    return "O"
  end
end

def won?(board)
  win_conditions.each do |win|
  #  returns an array of matching indexes for a win
  if win.all?{|y| board[y] == "X"}
    return win
    elsif win.all?{|y| board[y] == "O"}
      return win
    end
  end
  return false # returns false for an empty board / a draw
end

def full?(board)
  board.all? do |position|
    position == "X" || position == "O"
  end
end

def draw?(board)
  # true if no winner and board is full
  !(won?(board)) && full?(board)
end

    def over?(board)
      if full?(board) == true
        return true # returns true for a won game / draw
      end
      return false # returns false for an in-progress game
    end

def winner(board)
 # returns X when X won, O when O won and nill when no winner
 if (draw?(board) || !full?(board)) && !won?(board)
    return nil
  elsif (board[won?(board)[0]] == "X")
    return "X"
  elsif (board[won?(board)[0]] == "O")
    return "O"
  end
end

def play(board)
  while !over?(board) && !won?(board) && !draw?(board) # if the game isnt over
    turn(board) # play another turn
  end

# if the game is over
  if won?(board)
   puts "Congratulations #{winner(board)}!"
 end

# if its a draw
 if draw?(board)
   puts "Cats Game!"
 end

end