tic-tac-toe/main.py

#!/usr/bin/env python3
from random import choice
from enum import Enum
from sys import exit
from textwrap import dedent


class CellState(Enum):
    """
    Enum to track the state for a cell on the board
    X is a cell marked by the computer,
    O is a cell marked by the player,
    U is a cell that is unmarked
    """

    X = False
    O = True
    U = None


class TicTacToe:
    def __init__(self) -> None:
        self.board: list[list[CellState]] = [
            [CellState.U, CellState.U, CellState.U],
            [CellState.U, CellState.U, CellState.U],
            [CellState.U, CellState.U, CellState.U],
        ]
        self.turn = 0

    # Duplicate code in this function because I don't think I'm getting
    # a mutable reference in Python, and I don't know a better way :pensive:
    def change_state(self, cell: int, state: CellState) -> None:
        # Data integreity check cause this is Python rip
        if cell not in range(1, 10):
            raise ValueError(f"Cell {cell} is not a number 1-9.")
        if state.value is None:
            raise ValueError("Cell cannot be reset to initial state")
        # Okay cool now actually changing the state
        # Decrements cell by one to turn into a valid index
        index: int = cell - 1
        # Decides the row using floor divison on the index
        # (the amount of times index evenly divides into 3 is what list it will be in)
        row: int = index // 3
        # Gets the remanider of the previous operation to decide what row it's in
        col: int = index % 3
        self.board[row][col] = state

    def get_cell(self, cell: int):
        if cell not in range(1, 10):
            raise ValueError(f"Cell {cell} is not a number 1-9.")
        index: int = cell - 1
        # Decides the row using floor divison on the index
        # (the amount of times index evenly divides into 3 is what list it will be in)
        row: int = index // 3
        # Gets the remanider of the previous operation to decide what row it's in
        col: int = index % 3
        return self.board[row][col]

    def display_cell(self, cell: int) -> str:
        sign = self.get_cell(cell).name
        return sign if not sign == "U" else str(cell)

    def unmarked_cells(self) -> tuple[int, ...]:
        unmarked: list[int] = []
        for i in range(1, 10):
            if self.get_cell(i).value is None:
                unmarked.append(i)
            else:
                continue
        return tuple(unmarked)


def main():
    tic_tac_toe = TicTacToe()
    # Game loop
    while True:
        # Check to see if the game tied
        # (I'm too lazy to think about using turn count to do this quicker)
        if len(tic_tac_toe.unmarked_cells()) == 0:
            print("What a tie!")
            break
        # Incriment turn count
        tic_tac_toe.turn += 1
        # Emulate computer turn
        draw_move(tic_tac_toe)
        display_board(tic_tac_toe)
        # Check if computer won
        if victory_for(tic_tac_toe, CellState.X):
            print("Computer won :(")
            break
        # Start player turn
        enter_move(tic_tac_toe)
        display_board(tic_tac_toe)
        # Check if player won
        if victory_for(tic_tac_toe, CellState.O):
            print("You won!")
            break


def display_board(board: TicTacToe):
    # The function accepts one parameter containing the board's current status
    # and prints it out to the console.
    board_display = f"""\
    +-------+-------+-------+
    |       |       |       |
    |   {board.display_cell(1)}   |   {board.display_cell(2)}   |   {board.display_cell(3)}   |
    |       |       |       |
    +-------+-------+-------+
    |       |       |       |
    |   {board.display_cell(4)}   |   {board.display_cell(5)}   |   {board.display_cell(6)}   |
    |       |       |       |
    +-------+-------+-------+
    |       |       |       |
    |   {board.display_cell(7)}   |   {board.display_cell(8)}   |   {board.display_cell(9)}   |
    |       |       |       |
    +-------+-------+-------+
    """
    print(dedent(board_display), end="")


def enter_move(board: TicTacToe) -> None:
    # The function accepts the board's current status, asks the user about their move,
    # checks the input, and updates the board according to the user's decision.
    while True:
        user_input: str = input("Enter your move: ")
        cell: int
        try:
            cell = int(user_input)
        except ValueError:
            print("Please enter a valid value")
            continue
        if cell not in board.unmarked_cells():
            print("Please choose an unoccupied sqare")
            continue
        break
    board.change_state(cell, CellState.O)


def make_list_of_free_fields(board: TicTacToe) -> list[tuple[int, int]]:
    # The function browses the board and builds a list of all the free squares;
    # the list consists of tuples, while each tuple is a pair of row and column numbers.
    free_fields: list[tuple[int, int]] = []
    unmarked_cells = board.unmarked_cells()
    for i in unmarked_cells:
        cell = i
        free_fields.append((cell // 3 + 1, cell % 3 + 1))
    return free_fields


def victory_for(board: TicTacToe, sign: CellState) -> bool:
    # The function analyzes the board's status in order to check if
    # the player using 'O's or 'X's has won the game

    # The is certainly a better way to approach this, but oh well
    # For example, if any of the spaces in a condition are unmarked, then it should be ignored
    row1 = board.board[0]
    row2 = board.board[1]
    row3 = board.board[2]
    col1 = [row1[0], row2[0], row3[0]]
    col2 = [row1[1], row2[1], row3[1]]
    col3 = [row1[2], row2[2], row3[2]]
    diag1 = [row1[0], row2[1], row3[2]]
    diag2 = [row1[2], row2[1], row3[0]]
    win_conditions = [row1, row2, row3, col1, col2, col3, diag1, diag2]
    for condition in win_conditions:
        if all(state == sign for state in condition):
            return True
    return False


def draw_move(board: TicTacToe):
    # The function draws the computer's move and updates the board.
    # Puts an X in the middle of the board on the first turn, otherwise
    computer_cell: int = 5 if board.turn == 1 else choice(board.unmarked_cells())
    board.change_state(computer_cell, CellState.X)


if __name__ == "__main__":
    try:
        main()
        exit(0)
    except KeyboardInterrupt:
        print("\nQuitting game...")
        exit(0)
    except:
        exit(1)