#!/usr/bin/python3
# -*- coding: utf-8 -*-
"""
Tic Tac Toe
"""

import random
from typing import List


def drawBoard(board: List[str]) -> None:
    """
    This function prints out the board that it was passed.
    "board" is a list of 10 strings representing the board
    (ignore index 0)
    """
    print(board[7] + "|" + board[8] + "|" + board[9])
    print("-+-+-")
    print(board[4] + "|" + board[5] + "|" + board[6])
    print("-+-+-")
    print(board[1] + "|" + board[2] + "|" + board[3])


def inputPlayerLetter() -> List[str]:
    """
    Lets the player type which letter they want to be.
    Returns a list with the player's letter as the first item,
    and the computer's letter as the second.
    """
    letter = ""
    while not (letter == "X" or letter == "O"):
        print("Do you want to be X or O?")
        letter = input().upper()

    # the first element in the list is the player's letter,
    # the second is the computer's letter.
    if letter == "X":
        return ["X", "O"]
    else:
        return ["O", "X"]


def whoGoesFirst() -> str:
    """Randomly choose the player who goes first."""
    random.seed(0)
    if random.randint(0, 1) == 0:
        return "computer"
    else:
        return "player"


def makeMove(board: List[str], letter: str, move: int) -> None:
    """Assigns move to board list"""
    board[move] = letter


def isWinner(bo: List[str], le: str) -> bool:
    """
    Given a board and a player's letter,
    this function returns True if that player has won.
    We use bo instead of board and le instead of letter
    so we don't have to type as much.
    """
    return (
        (bo[7] == le and bo[8] == le and bo[9] == le)
        or (bo[4] == le and bo[5] == le and bo[6] == le)  # across the top
        or (bo[1] == le and bo[2] == le and bo[3] == le)  # across the middle
        or (bo[7] == le and bo[4] == le and bo[1] == le)  # across the bottom
        or (bo[8] == le and bo[5] == le and bo[2] == le)  # down the left side
        or (bo[9] == le and bo[6] == le and bo[3] == le)  # down the middle
        or (bo[7] == le and bo[5] == le and bo[3] == le)  # down the right side
        or (bo[9] == le and bo[5] == le and bo[1] == le)  # diagonal
    )  # diagonal


def getBoardCopy(board: List[str]) -> List[str]:
    """Make a copy of the board list and return it."""
    boardCopy = []
    for i in board:
        boardCopy.append(i)
    return boardCopy


def isSpaceFree(board: List[str], move: int) -> bool:
    """Return true if the passed move is free on the passed board"""
    return board[move] == " "


def getPlayerMove(board: List[str]) -> int:
    """Let the player type in their move."""
    move = " "
    while move not in "1 2 3 4 5 6 7 8 9".split() or not isSpaceFree(board, int(move)):
        print("What is your next move? (1-9)")
        move = input()
    return int(move)


def chooseRandomMoveFromList(board: List[str], movesList: List[int]) -> int:
    """
    Returns a valid move from the passed list on the passed board.
    Returns None if there is no valid move.
    """
    possibleMoves = []
    for i in movesList:
        if isSpaceFree(board, i):
            possibleMoves.append(i)

    assert len(possibleMoves) > 0, "Must have space on board"
    return random.choice(possibleMoves)


def getComputerMove(board: List[str], computerLetter: str) -> int:
    """
    Given a board and the computer's letter,
    determine where to move and return that move.
    """
    if computerLetter == "X":
        playerLetter = "O"
    else:
        playerLetter = "X"

    # Here is our algorithm for our Tic Tac Toe AI:
    # First, check if we can win in the next move
    # This is entertaining a possible future world.
    # Who says computers don't have imagination?
    for i in range(1, 10):
        boardCopy = getBoardCopy(board)
        if isSpaceFree(boardCopy, i):
            makeMove(boardCopy, computerLetter, i)
            if isWinner(boardCopy, computerLetter):
                return i

    # Check if the player could win on his next move, and block them.
    for i in range(1, 10):
        boardCopy = getBoardCopy(board)
        if isSpaceFree(boardCopy, i):
            makeMove(boardCopy, playerLetter, i)
            if isWinner(boardCopy, playerLetter):
                return i

    # Try to take one of the corners, if they are free.
    move = chooseRandomMoveFromList(board, [1, 3, 7, 9])
    if move is not None:
        return move

    # Try to take the center, if it is free.
    if isSpaceFree(board, 5):
        return 5

    # Move on one of the sides.
    return chooseRandomMoveFromList(board, [2, 4, 6, 8])


def isBoardFull(board: List[str]) -> bool:
    """
    Return True if every space on the board has been taken.
    Otherwise return False.
    """
    for i in range(1, 10):
        if isSpaceFree(board, i):
            return False
    return True


def main() -> None:
    print("Welcome to Tic Tac Toe!")

    while True:
        # Reset the board
        theBoard = [" "] * 10
        playerLetter, computerLetter = inputPlayerLetter()
        turn = whoGoesFirst()
        print("The " + turn + " will go first.")
        gameIsPlaying = True

        while gameIsPlaying:
            if turn == "player":
                # Player's turn.
                drawBoard(theBoard)
                move = getPlayerMove(theBoard)
                makeMove(theBoard, playerLetter, move)

                if isWinner(theBoard, playerLetter):
                    drawBoard(theBoard)
                    print("Hooray! You have won the game!")
                    gameIsPlaying = False
                else:
                    if isBoardFull(theBoard):
                        drawBoard(theBoard)
                        print("The game is a tie!")
                        break
                    else:
                        turn = "computer"

            else:
                # Computer's turn.
                move = getComputerMove(theBoard, computerLetter)
                makeMove(theBoard, computerLetter, move)

                if isWinner(theBoard, computerLetter):
                    drawBoard(theBoard)
                    print("The computer has beaten you! You lose.")
                    gameIsPlaying = False
                else:
                    if isBoardFull(theBoard):
                        drawBoard(theBoard)
                        print("The game is a tie!")
                        break
                    else:
                        turn = "player"

        print("Do you want to play again? (yes or no)")
        if not input().lower().startswith("y"):
            break


if __name__ == "__main__":
    main()