Python - CLI Minesweeper

Question

I've written the following single-script minesweeper console game and would appreciate your feedback!

What I'm interested in:

• Enums: I think the usage of Enums could be better. It feels weird that I need to make the player_field a List[List[Union[int, PlayerFieldState]]] instead of simply a List[List[PlayerFieldState]]
• Separation of I/O and game logic: I think there is quite a bit of code which only deals with fixing user input / outputting the field to the user. Is there a nice way to separate both?
• Anything that would make the code easier to read / more concise

What I'm not interested in:

• Pure formatting: I use black and isort and I'm pretty happy with that.

Code

You need Python 3.6+ with numpy to execute the following:

# Core Library modules
import enum
from typing import List, Tuple, cast, Union

# Third party modules
import numpy as np


def main():
    game = Game(n=10, m=10, nb_mines=10)
    while game.is_running:
        game.take_step()


class PlayerFieldState(enum.Enum):
    ZERO = 0
    ONE = 1
    TWO = 2
    THREE = 3
    FOUR = 4
    FIVE = 5
    SIX = 6
    SEVEN = 7
    EIGHT = 8
    UNDISCOVERED = 9
    EXPLODED_BOMB = 10
    MARKED = 11


class PlayerAction(enum.Enum):
    EXPLORE = 0
    MARK = 1


field_state2str = {
    0: "  ",
    1: "1 ",
    2: "2 ",
    3: "3 ",
    4: "4 ",
    5: "5 ",
    6: "6 ",
    7: "7 ",
    8: "8 ",
    PlayerFieldState.UNDISCOVERED: "? ",
    PlayerFieldState.EXPLODED_BOMB: "💥",
    PlayerFieldState.MARKED: "📌",
}


class Game:
    def __init__(self, n: int, m: int, nb_mines: int):
        self.mine_field = Game.create_field(n, m, nb_mines)
        self.player_field: List[List[Union[int, PlayerFieldState]]] = [
            [PlayerFieldState.UNDISCOVERED for _ in range(m)] for _ in range(n)
        ]
        self.is_running = True
        self.nb_mines = nb_mines
        self.nb_marked = 0

    @staticmethod
    def create_field(n: int, m: int, nb_mines: int) -> List[List[bool]]:
        field = np.zeros(n * m, dtype=bool)
        for i in range(nb_mines):
            field[i] = True
        np.random.shuffle(field)
        field = field.reshape((n, m))
        return field.tolist()

    def print_field(self, uncover: bool = False):
        top_line = ["  "] + [str(y) + " " for y in range(len(self.player_field[0]))]
        top_line_str = " ".join(top_line)
        print(top_line_str)
        print("-" * len(top_line_str))
        for x, line in enumerate(self.player_field):
            to_print = [str(x) + "|"]
            for y, field in enumerate(line):
                el = field_state2str[field]
                if uncover:
                    if (
                        self.mine_field[x][y]
                        and field != PlayerFieldState.EXPLODED_BOMB
                    ):
                        el = "💣"
                    if field == PlayerFieldState.MARKED:
                        if not self.mine_field[x][y]:
                            el = "😖"
                        else:
                            el = "📌"
                to_print.append(el)
            print(" ".join(to_print))
        print("-" * len(top_line_str))
        print(top_line_str)

    def take_step(self):
        self.print_field()
        x, y, step_type = self.get_valid_input()
        if step_type == PlayerAction.MARK:
            self.take_step_mark_bomb(x, y)
        elif step_type == PlayerAction.EXPLORE:
            self.take_step_explore(x, y)
        else:
            raise ValueError(f"step_type={step_type} is not known")

    def take_step_mark_bomb(self, x: int, y: int):
        if self.player_field[x][y] == PlayerFieldState.MARKED:
            self.player_field[x][y] = PlayerFieldState.UNDISCOVERED
            self.nb_marked -= 1
        elif self.player_field[x][y] == PlayerFieldState.UNDISCOVERED:
            self.player_field[x][y] = PlayerFieldState.MARKED
            self.nb_marked += 1
            self.check_win_condition()

    def take_step_explore(self, x: int, y: int):
        if self.player_field[x][y] == PlayerFieldState.MARKED:
            print(f"Please unmark ({x},{y}) before you hit it.")
        elif self.mine_field[x][y]:
            self.player_field[x][y] = PlayerFieldState.EXPLODED_BOMB
            self.is_running = False
            print("Game over")
            self.print_field(uncover=True)
        else:
            self.uncover(x, y)

    def check_win_condition(self):
        if self.nb_marked == self.nb_mines:
            print(
                f"You have marked {self.nb_marked} fields with mines. "
                "This is equal to the number of hidden mines."
            )
            stop_game = get_yes_no("Do you want to finish the game?")
            if stop_game:
                self.is_running = False
                if self.are_mines_marked_correctly():
                    print("You won!")
                else:
                    print("You lose!")
                    self.print_field(uncover=True)

    def uncover(self, x: int, y: int):
        adjacent_mines = self.get_adjacent_mines(x, y)
        self.player_field[x][y] = adjacent_mines
        if adjacent_mines == 0:
            for xn, yn in self.get_neighbors(x, y):
                if self.player_field[xn][yn] == PlayerFieldState.UNDISCOVERED:
                    self.uncover(xn, yn)

    def get_neighbors(self, x: int, y: int) -> List[Tuple[int, int]]:
        neighbors = []
        for xd in [-1, 0, 1]:
            for yd in [-1, 0, 1]:
                if xd == 0 and yd == 0:
                    continue
                if self.is_on_field(x + xd, y + yd):
                    neighbors.append((x + xd, y + yd))
        return neighbors

    def get_adjacent_mines(self, x: int, y: int) -> int:
        adjacent_mines = 0
        for xn, yn in self.get_neighbors(x, y):
            adjacent_mines += self.is_mine(xn, yn)
        return adjacent_mines

    def is_on_field(self, x: int, y: int) -> bool:
        return 0 <= x < len(self.mine_field) and 0 <= y < len(self.mine_field[0])

    def is_mine(self, x: int, y: int) -> bool:
        if not self.is_on_field(x, y):
            return False
        return self.mine_field[x][y]

    def get_valid_input(self) -> Tuple[int, int, PlayerAction]:
        position = None
        while not self.is_valid_input(position):
            position = input(
                "Where would you like to hit " "(add ',m' if you want to mark a bomb)? "
            )
        position = cast(str, position)
        splitted = position.split(",")
        x = int(splitted[0])
        y = int(splitted[1])
        if len(splitted) == 3:
            if splitted[2] == "m":
                t = PlayerAction.MARK
            else:
                t = PlayerAction.EXPLORE
        else:
            t = PlayerAction.EXPLORE
        return x, y, t

    def is_valid_input(self, position):
        if position is None:
            return False
        if "," not in position:
            return False
        splitted = position.split(",")
        x = splitted[0]
        y = splitted[1]
        if len(splitted) == 3:
            t = splitted[2]
            if t not in ["m", "b"]:
                return False
        try:
            x = int(x)
            y = int(y)
            if not self.is_on_field(x, y):
                return False
            return True
        except:
            return False

    def are_mines_marked_correctly(self):
        for x, line in enumerate(self.mine_field):
            for y, is_mine in enumerate(line):
                if is_mine:
                    if self.player_field[x][y] != PlayerFieldState.MARKED:
                        return False
                else:
                    if self.player_field[x][y] == PlayerFieldState.MARKED:
                        return False
        return True


def get_yes_no(message: str) -> bool:
    value = input(message)
    while value not in ["Y", "y", "N", "n", "yes", "no", "1", "0"]:
        value = input(message + " [y/n] ")
    return value in ["Y", "y", "yes", "1"]


if __name__ == "__main__":
    main()

Answer 1

Requirements

You need Python 3.6+

So at the least, you should add a shebang:

#!/usr/bin/env python3

with numpy

should go in a requirements.txt.

Definition order

You define main at the top. Call me old-fashioned, but I'm used to stricter languages where the referred symbols in a function need to be defined before that function. I still consider defining things in dependence order to be more legible, and suggest that main go at the bottom.

Enum

Use unique and auto:

@unique
class PlayerFieldState(Enum):
    UNDISCOVERED = auto()
    EXPLODED_BOMB = auto()
    MARKED = auto()

I think it's probably inappropriate to represent the values 0-8 in that enum; they should be stored in a different variable. It looks like you're already going in that direction? given this:

self.player_field: List[List[Union[int, PlayerFieldState]]]

In other words: why have an int-state union if your state captures ints?

Numpy

    return field.tolist()

Why the tolist call? Wouldn't leaving the field as a Numpy array be a more efficient representation?

Iterating coordinates

get_neighbors probably shouldn't return a list. Instead, make it a generator, and don't do iterative concatenation. Something like:

    for xd in [-1, 0, 1]:
        xa = x + xd
        for yd in [-1, 0, 1]:
            ya = y + yd
            if self.is_on_field(xa, ya) and not (xd == 0 and yd == 0):
                yield xa, ya

The same goes for get_adjacent_mines.

Boolean expressions

    if not self.is_on_field(x, y):
        return False
    return self.mine_field[x][y]

can be

return self.is_on_field(x, y) and self.mine_field[x][y]

Sets for validation

while value not in ["Y", "y", "N", "n", "yes", "no", "1", "0"]:
    value = input(message + " [y/n] ")
return value in ["Y", "y", "yes", "1"]

can be

yes_vals = {"Y", "y", "yes", "1"}
no_vals = {"N", "n", "no", "0"}
while value not in yes_vals|no_vals:
    value = input(message + " [y/n] ")
return value in yes_vals

Your loop structure could also be simplified. Just do a while True, do one input, check for membership and return:

yes_vals = {"Y", "y", "yes", "1"}
no_vals = {"N", "n", "no", "0"}
while True:
    value = input(message + " [y/n] ")
    if value in yes_vals|no_vals:
        return value in yes_vals