tictactoe.py

""" Tic tac toe code exercise with dataclasses.

Usage:
	import tictactoe as ttt
	game = ttt.Game()
	game.make_move(x, y)

"""

from dataclasses import dataclass
import collections

@dataclass
class Game:
	"""Class for keeping track of the game state."""
	rows: int = 3
	columns: int = 3
	board: str = None
	players: str = None
	whose_turn: str = 'X'
	empty_char: str = '*'
	winner = None

	def __init__(self):
		self.board = []
		for pos in range(self.rows):
			self.board.append(
				[self.empty_char] * self.columns)
		self.players = ['X', 'O']
		self.print_board()
		self.message_next_turn()

	def message_next_turn(self):
		print(f'{self.whose_turn}\'s move')

	def is_winning_set(self, positions):
		if (len(positions) is 1) and (self.empty_char not in positions):
			return ''.join(positions)
		else:
			return None

	def find_horizontal_winner(self, board):
		for row in board:
			row_set = set(row)
			is_winner = self.is_winning_set(set(row))
			if is_winner is not None:
				return is_winner

	def evaluate_game(self):
		# Check rows for winner
		winner = self.find_horizontal_winner(self.board)
		if winner is not None:
			return winner

		# Check columns (rotated board) for winner
		rotated_board = ("\n".join(map(
			"".join,zip(*self.board)))).split('\n')
		winner = self.find_horizontal_winner(rotated_board)
		if winner is not None:
			return winner

		# Check diamond for winner, only do it on an odd-sized square board
		if (
			(self.rows * self.columns) % 2 == 1
		) and self.rows == self.columns:
			winner = self.is_winning_set(set([
				# Rewrite as list comprehension?
				self.board[0][0],
				self.board[1][1],
				self.board[2][2]
			]))
			if winner is not None:
				return winner

			winner = self.is_winning_set(set([
				# Rewrite as list comprehension?
				self.board[2][0],
				self.board[1][1],
				self.board[0][2]
			]))
			if winner is not None:
				return winner

		return winner

	def print_board(self):
		for row in self.board:
			print(' '.join(row))

	def make_move(self, x, y):
		# Lock out making moves on a won game
		if self.winner is None:
			# Lock out making moves on a filled position
			if self.board[x][y] == self.empty_char:
				# Add the move to the position whose turn it is
				self.board[x][y] = self.whose_turn
				# Rotate the player whose turn it is
				self.whose_turn = self.players[(
						self.players.index(self.whose_turn) + 1
					) % len(self.players)]
				# Show the updated board results
				self.print_board()
				# Find a winner
				self.winner = self.evaluate_game()
				# If no winner say whose turn it is next
				if self.winner is None:
					self.message_next_turn()
				else:
					print(f'{self.winner} wins!')
			else:
				raise ValueError(f'Board is already filled at {x}, {y}')
		else:
			print(f'Game completed.\n{self.winner} Won!\n\nStart a new game.')