from tkinter import *
from tkinter.ttk import *

PLAYER1 = "X"
PLAYER2 = "O"
SIZE = 3    # length of board side

class TicTacToe:
    '''A graphical game of Tic Tac Toe using tkinter.'''

    def __init__(self, window):
        '''Initialize the game window components.'''
        
        window.title("Tic-Tac-Toe")
        style = Style()
        style.configure('TButton', font=('Sans', '48', 'bold'), padding=30)
        style.configure('TLabel', font=('Sans', '24', 'bold'))
        
        self.display_text = StringVar()
        display = Label(window, textvariable=self.display_text)
        display.grid(row=0, column=0, columnspan=SIZE)

        self.populate_board(window)

        self.turn = PLAYER1
        self.display_text.set('Next player: ' + self.turn)   
    
    
    def populate_board(self, window):
        '''Set up the buttons making up the game board.'''
        self.board = []
        for row_num in range(SIZE):
            board_row = []
            for col_num in range(SIZE):
                button_text = StringVar()
                button = Button(
                    window,
                    textvariable = button_text,
                    command = self.button_action(row_num, col_num),
                    width = 1 # make buttons square
                )
                button.grid(row=row_num + 1, column=col_num)
                board_row.append(button_text)
            self.board.append(board_row)        


    def button_action(self, row_num, col_num):
        '''Construct a callback function for the given (row, col).'''
        
        def button_callback():
            '''Executes whenever a button is clicked to make a play.'''
            button_text = self.board[row_num][col_num]
            
            if button_text.get() == '':
            
                # making the play
                if self.turn == PLAYER1:
                    button_text.set(PLAYER1)
                else:
                    button_text.set(PLAYER2)
                    
                # check if the active player won
                if self.check_win(row_num, col_num):
                    self.display_text.set(self.turn + ' wins!')
                else:
                
                    # switch the active player
                    if self.turn == PLAYER1:
                        self.turn = PLAYER2
                    else:
                        self.turn = PLAYER1
            
                    self.display_text.set('Next player: ' + self.turn)
                
        return button_callback
    
    def check_win(self, row_clicked, col_clicked):
        '''Check whether the current player won with the last
        (row_clicked, col_clicked) play.'''
        
        # check if row row_clicked is a winner
        win_so_far = True
        for col in range(SIZE):
            # check (row_clicked, col)
            if self.board[row_clicked][col].get() != self.turn:
                # not a win in this row
                win_so_far = False
                break
        if win_so_far:
            return True
            
        # check if col col_clicked is a winner
        win_so_far = True
        for row in range(SIZE):
            # check (row, col_clicked)
            if self.board[row][col_clicked].get() != self.turn:
                # not a win in this col
                win_so_far = False
                break
        if win_so_far:
            return True        
        
        # check diags
        win_so_far = True
        for i in range(SIZE):
            if self.board[i][i].get() != self.turn:
                # not a win in this diag
                win_so_far = False
                break
        if win_so_far:
            return True       
        
        # check diags
        win_so_far = True
        for i in range(3):
            if self.board[i][SIZE - 1 - i].get() != self.turn:
                # not a win in this diag
                win_so_far = False
                break
        if win_so_far:
            return True     
        
        # otherwise, not a winner
        return False
    

def main():
    window = Tk()
    TicTacToe(window)
    window.mainloop()
    
main()