# tictactoe.py
# YOUR NAMES HERE, and Titus Klinge
#
# A simple game of tic tac toe. It requires that Zelle's
# graphics.py is in the same directory as this file.

from graphics import *

# Draws the board to the GraphWin object given.
#
# PARAMETERS:
#   win,   a GraphWin object
#   board, a 3x3 list of "", "X", and "O" characters
#
# RETURNS:
#   nothing, it only draws to the win object
#
# POSTCONDITIONS:
#   - Four lines are drawn on the GraphWin object that separates
#     it into a 3x3 grid
#   - Each character from the board parameter is printed
#     centered in its appropriate square on the grid
def drawBoard(win, board):
    return # IMPLEMENT ME!

# Updates the board with the current player's mouse click
# location.
#
# PARAMETERS:
#   board, a 3x3 list of "", "X", and "O" characters
#   point, a graphics.py Point object of where the player clicked
#   player, either "X" or "O" depending on the current player
#
# RETURNS:
#   nothing, it only changes the board object
#
# PRECONDITONS:
#   - point is a valid location in a cell that has not been previously
#     clicked by either player
#
# POSTCONDITIONS:
#   - The 3x3 board is updated so that the appropriate cell is
#     replaced by the player's character
def updateBoard(board, point, player):
    return # IMPLEMENT ME!

# Checks if the player's selection has been previously picked
# earlier in the game.
#
# PARAMETERS
#   board, a 3x3 list of "", "X", and "O" characters
#   point, a graphics.py Point object of where the player clicked
#
# RETURNS:
#   True if the play has not been previously picked and
#   False otherwise
def validMove(board, point):
    return True # IMPLEMENT ME

# Checks if a player has won the game.
#
# PARAMETERS:
#   board, a 3x3 list of "", "X", and "O" characters
#
# RETURNS:
#   ""  if neither player has three in a row
#   "X" if player X wins
#   "O" if player O wins
def checkWinner(board):
    return "" # IMPLEMENT ME

# Shows a message to the user what the outcome of the game was.
#
# PARAMETERS:
#   win,    a GraphWin object
#   winner, "X", "O", or "" (i.e. the winner of the game)
#
# RETURNS:
#   nothing, it just draws to the window
#
# POSTCONDITIONS:
#   - If winner = "X", a message is displayed that X wins
#   - If winner = "O", a message is displayed that O wins
#   - If winner = "", a message is displayed that the game was a draw
def drawEndGameMessage(win, winner):
    return # IMPLEMENT ME


# The main function that is called when the program is run.
def main():

    # Initializes the window
    win = GraphWin("Tic-Tac-Toe", 240, 240)
    win.setBackground("white")
    win.setCoords(0.0, 0.0, 3.0, 3.0)

    # Initializes the board to all empty strings which means
    # that no player has picked any cell yet. When a spot in
    # the board is selected by a player, it will be updated
    # to either an "X" or an "O"
    board = [["", "", ""],
             ["", "", ""],
             ["", "", ""]]

    # The player characters.
    #  - Player 0 is "X"
    #  - Player 1 is "O"
    players = ["X", "O"]
    curPlayer = 0

    # To keep track of who won the game
    #  - winner = ""  if no one has won yet
    #  - winner = "X" if Player 0 won
    #  - winner = "O" if Player 1 won
    winner = ""

    # Keeps track of the number of moves so far
    movesSoFar = 0

    # The main game loop. Will continue looping until the game is over
    while movesSoFar < 9 and winner == "" and win.isOpen():

        # Waits until the current player clicks somewhere on the window
        point = win.getMouse()

        # If the selection is a valid move...
        if validMove(board, point):
            # Update the board, check for the winner, switch players,
            # and draw the updated board
            updateBoard(board, point, players[curPlayer])
            winner = checkWinner(board)
            curPlayer = 1 - curPlayer
            movesSoFar = movesSoFar + 1
            drawBoard(win, board)

    # If the window is still open when the game is finished, show a message
    if win.isOpen():
        drawEndGameMessage(win, winner)

        # Wait until the user clicks before ending the program
        win.getMouse()

if __name__ == "__main__":
    main()