class Cell:

    def __init__(self, x, y):
        self.x = x
        self.y = y
        self.is_wall = False
        self.is_start = False
        self.is_exit = False

    def is_passable(self):
        return not self.is_wall
    def __repr__(self):
        return f"Cell({self.x}, {self.y})"
    
class Maze:

    def __init__(self, width, height):
        self.width = width
        self.height = height
        self.cells = []
        self.start = None
        self.exit = None

        for y in range(height):
            row = []
            for x in range(width):
                row.append(Cell(x, y))
            self.cells.append(row)

    def get_cell(self, x, y):

        if 0 <= x < self.width and 0 <= y < self.height:
            return self.cells[y][x]
        return None
    
    def get_neighbors(self, cell):

        neighbors = []
        directions = [(0, -1), (0, 1), (-1, 0), (1,0)]

        for dx, dy in directions:
            nx, ny = cell.x + dx, cell.y + dy
            neighbor = self.get_cell(nx, ny)
            if neighbor and neighbor.is_passable():
                neighbors.append(neighbor)
        return neighbors
    
    def __repr__(self):
        return f"Maze({self.width}x{self.height})"
    

from abc import ABC, abstractmethod

class MazeBuilder(ABC):

    @abstractmethod
    def build_from_file(self, filename):
        pass

class TextFileMazeBuilder(MazeBuilder):

    def build_from_file(self, filename):
        
        with open(filename, 'r', encoding='utf-8') as f:
            lines = f.readlines()

        lines = [line.rstrip('\n\r') for line in lines]

        height = len(lines)
        width = len(lines[0]) if height > 0 else 0
        
        for i, line in enumerate(lines):
            if len(line) != width:
                raise ValueError(f"Строка {i+1} имеет длину {len(line)}, ожидается {width}")
            
        maze = Maze(width, height)
        start = None
        exit_cell = None

        for y, line in enumerate(lines):
            for x, ch in enumerate(line):
                cell = maze.get_cell(x, y)

                if ch == '#':
                    cell.is_wall = True
                elif ch == ' ':
                    cell.is_wall = False
                elif ch == 'S':
                    cell.is_wall = False
                    cell.is_start = True
                    start = cell
                elif ch == 'E':
                    cell.is_wall = False
                    cell.ia_exit = True
                    exit_cell = cell
                else:
                    cell.is_wall = True
        
        if start is None:
            raise ValueError("В лабиринте не найден старт (S)")
        if exit_cell is None:
            raise ValueError("В лабиринте не найден выход (E)")
        
        maze.start = start
        maze.exit = exit_cell

        return maze
    
    #тест

if __name__ == "__main__":
    builder = TextFileMazeBuilder()
    maze = builder.build_from_file("maze1.txt")

    print(f"лабиринт загружен: {maze}")
    print(f"старт: {maze.start}")
    print(f"выход: {maze.exit}")

    neighbors = maze.get_neighbors(maze.start)
    print(f"соседи старта: {neighbors}")