# implement a simple text based tic-tac-toe game
import numpy as np

class TicTacToe():

    def __init__(self, size=(3,3)):
        self.size = size
        self.board = np.zeros(size, dtype=int)
        self.player = 1  # the player whoes turn it is to play
        self.winner = 0  # the winner, 0 for draw
        self.done = 0  # if the game is done or not
        self.turn = 0  # the current turn, maximum is 9

    def input_is_valid(self, move):
        """
        Check if the move one of the the players want to take is a valid move in
        the current situation.

        The move is valid if there is nothing where the player want to draw and
        if the move is inside the grid.
        """

        # todo catch error if out of bounds
        unraveled_index = np.unravel_index(move, self.size)

        if self.board[unraveled_index] == 0:
            return True
        else:
            return False

    def update_board(self, move):
        """
        Update board if move is valid
        """

        if self.input_is_valid(move):
            unraveled_index = np.unravel_index(move, self.size)
            self.board[unraveled_index] = self.player

        # change player
        self.player = 3 - self.player 

        # update turn counter
        self.turn += 1

    def check_win(self):
        """
        Check if the current board is in a winning position.
        Return 0 if it is not and the player id (1 or 2) if it is.
        """

        # impossible to win in less than 5 moves
        if self.turn < 5:
            return 0
        
        # check rows
        rows = self.board
        for r in rows:
            if (r == 1).all():
                self.winner = 1
            if (r == 2).all():
                self.winner = 2

        # check columns
        columns = self.board.T
        for c in columns:
            if (c == 1).all():
                self.winner = 1
            if (c == 2).all():
                self.winner = 2

        # check diagonals
        diagonals = [self.board.diagonal(), np.fliplr(self.board).diagonal()]
        for d in diagonals:
            if (d == 1).all():
                self.winner = 1
            if (d == 2).all():
                self.winner = 2

        # handle draw
        if self.turn == 9:
            self.done = 1

        # if someone won
        if self.winner != 0:
            self.done = 1

        # if no winning conidition has been found
        return self.winner

    def display_board(self):
        """
        Display a humanly readable board.

        Example:
        +---+---+---+
        | X | O |   |
        +---+---+---+
        | O | X |   |
        +---+---+---+
        | X |   | O |
        +---+---+---+
        """

        line_decorator = "+---+---+---+"
        board_decorator = "| {} | {} | {} |"

        convert = {0: " ", 1: "X", 2: "O"}

        for r in self.board:
            print(line_decorator)

            L = []
            for i in r:
                L.append(convert[i])

            print(board_decorator.format(*L))

        print(line_decorator)