basic-computer-games/90_Tower/python/tower.py

import sys
from typing import List, Optional


class Disk:
    def __init__(self, size: int) -> None:
        self.__size = size

    def size(self) -> int:
        return self.__size

    def print(self) -> None:
        print(f"[ {self.size()} ]")


class Tower:
    def __init__(self) -> None:
        self.__disks: List[Disk] = []

    def empty(self) -> bool:
        return len(self.__disks) == 0

    def top(self) -> Optional[Disk]:
        return None if self.empty() else self.__disks[-1]

    def add(self, disk: Disk) -> None:
        if not self.empty():
            t = self.top()
            assert t is not None  # cannot happen as it's not empty
            if disk.size() > t.size():
                raise Exception(
                    "YOU CAN'T PLACE A LARGER DISK ON TOP OF A SMALLER ONE, IT MIGHT CRUSH IT!"
                )
        self.__disks.append(disk)

    def pop(self) -> Disk:
        if self.empty():
            raise Exception("empty pop")
        return self.__disks.pop()

    def print(self) -> None:
        r = f'Needle: [{", ".join([str(x.size()) for x in self.__disks])}]'
        print(r)


class Game:
    def __init__(self) -> None:
        # use fewer sizes to make debugging easier
        # self.__sizes = [3, 5, 7]  # ,9,11,13,15]
        self.__sizes = [3, 5, 7, 9, 11, 13, 15]

        self.__sizes.sort()

        self.__towers = []
        self.__moves = 0
        self.__towers = [Tower(), Tower(), Tower()]
        self.__sizes.reverse()
        for size in self.__sizes:
            disk = Disk(size)
            self.__towers[0].add(disk)

    def winner(self) -> bool:
        return self.__towers[0].empty() and self.__towers[1].empty()

    def print(self) -> None:
        for t in self.__towers:
            t.print()

    def moves(self) -> int:
        return self.__moves

    def which_disk(self) -> int:
        w = int(input("WHICH DISK WOULD YOU LIKE TO MOVE\n"))
        if w in self.__sizes:
            return w
        raise Exception()

    def pick_disk(self) -> Optional[Tower]:
        which = None
        while which is None:
            try:
                which = self.which_disk()
            except Exception:
                print("ILLEGAL ENTRY... YOU MAY ONLY TYPE 3,5,7,9,11,13, OR 15.\n")

        valids = [t for t in self.__towers if t.top() and t.top().size() == which]
        assert len(valids) in {0, 1}
        if not valids:
            print("THAT DISK IS BELOW ANOTHER ONE.  MAKE ANOTHER CHOICE.\n")
            return None
        else:
            assert valids[0].top().size() == which
            return valids[0]

    def which_tower(self) -> Optional[Tower]:
        try:
            needle = int(input("PLACE DISK ON WHICH NEEDLE\n"))
            tower = self.__towers[needle - 1]
        except Exception:
            print(
                "I'LL ASSUME YOU HIT THE WRONG KEY THIS TIME.  BUT WATCH IT,\nI ONLY ALLOW ONE MISTAKE.\n"
            )
            return None
        else:
            return tower

    def take_turn(self) -> None:
        from_tower = None
        while from_tower is None:
            from_tower = self.pick_disk()

        to_tower = self.which_tower()
        if not to_tower:
            to_tower = self.which_tower()

        if not to_tower:
            print("I TRIED TO WARN YOU, BUT YOU WOULDN'T LISTEN.\nBYE BYE, BIG SHOT.\n")
            sys.exit(0)

        disk = from_tower.pop()
        try:
            to_tower.add(disk)
            self.__moves += 1
        except Exception as err:
            print(err)
            from_tower.add(disk)


def main() -> None:
    print(
        """
    IN THIS PROGRAM, WE SHALL REFER TO DISKS BY NUMERICAL CODE.
    3 WILL REPRESENT THE SMALLEST DISK, 5 THE NEXT SIZE,
    7 THE NEXT, AND SO ON, UP TO 15.  IF YOU DO THE PUZZLE WITH
    2 DISKS, THEIR CODE NAMES WOULD BE 13 AND 15.  WITH 3 DISKS
    THE CODE NAMES WOULD BE 11, 13 AND 15, ETC.  THE NEEDLES
    ARE NUMBERED FROM LEFT TO RIGHT, 1 TO 3.  WE WILL
    START WITH THE DISKS ON NEEDLE 1, AND ATTEMPT TO MOVE THEM
    TO NEEDLE 3.

    GOOD LUCK!

    """
    )

    game = Game()
    while True:
        game.print()

        game.take_turn()

        if game.winner():
            print(
                "CONGRATULATIONS!!\nYOU HAVE PERFORMED THE TASK IN %s MOVES.\n"
                % game.moves()
            )
            while True:
                yesno = input("TRY AGAIN (YES OR NO)\n")
                if yesno.upper() == "YES":
                    game = Game()
                    break
                elif yesno.upper() == "NO":
                    print("THANKS FOR THE GAME!\n")
                    sys.exit(0)
                else:
                    print("'YES' OR 'NO' PLEASE\n")
        elif game.moves() > 128:
            print("SORRY, BUT I HAVE ORDERS TO STOP IF YOU MAKE MORE THAN 128 MOVES.")
            sys.exit(0)


if __name__ == "__main__":
    main()