import random
from itertools import product
from typing import Tuple, Set, Union, Any, List, NamedTuple
from pprint import pprint


class Cell(NamedTuple):
    x: int
    y: int


class Wall(NamedTuple):
    first_cell: Cell
    second_cell: Cell


class Maze:
    def __init__(self, width: int, height: int):
        self.cells = set(Cell(*c) for c in product(range(width), range(height)))
        self.maze = dict()
        for cell in self.cells:
            self.maze[cell] = self.get_neighbours(cell)
        self.walls = self.get_walls()
        self.generate_maze()

    def get_neighbours(self, cell: Cell) -> Set[Cell]:
        diffs = ((0, 1), (0, -1), (1, 0), (-1, 0))
        return set(Cell(cell.x + x, cell.y + y) for x, y in diffs if Cell(cell.x + x, cell.y + y) in self.cells)

    def get_walls(self) -> Set[Wall]:
        walls = set()
        for cell in self.cells:
            walls.update(set(Wall(*sorted([cell, c])) for c in self.maze[cell]))
        return walls

    def generate_maze(self) -> None:
        visited = set()
        unvisited = list(self.cells)
        node = random.choice(unvisited)
        visited.add(node)
        unvisited.remove(node)
        while unvisited:
            random_neighbour = random.choice(list(self.maze[node]))
            if random_neighbour not in visited:
                self.walls.remove(Wall(*sorted([node, random_neighbour])))
                visited.add(random_neighbour)
                try:
                    unvisited.remove(random_neighbour)
                except ValueError:
                    pass
            node = random_neighbour

    def generate_prim_maze(self) -> None:
        visited = set()
        node = random.choice(list(self.cells))
        visited.add(node)
        removed_walls = set()
        wall_list = [w for w in self.walls if node in w]
        while wall_list:
            random_wall = random.choice(wall_list)
            wall_list.remove(random_wall)
            cell1, cell2 = random_wall
            if (cell1 in visited) != (cell2 in visited):
                removed_walls.add(random_wall)
                self.walls.remove(random_wall)
                visited.add(cell1)
                visited.add(cell2)
                wall_list.extend(
                    set(w for w in self.walls if (cell1 in w) or (cell2 in w)).difference(removed_walls)
                )


if __name__ == "__main__":
    maze = Maze(3, 3)
    pprint(maze.walls)