from collections import deque
import heapq
import time
from abc import ABC, abstractmethod

# Модель 
class Cell:
    def __init__(self, x, y, is_wall=False, is_start=False, is_exit=False):
        self.x = x
        self.y = y
        self.is_wall = is_wall
        self.is_start = is_start
        self.is_exit = is_exit
        self.visited = False  

    def is_passable(self):
        return not self.is_wall


class Player:
    def __init__(self, start_cell):
        self.current_cell = start_cell
        
        
class Maze:
    def __init__(self, width, height):
        self.width = width
        self.height = height
        self.cells = [[Cell(x, y) for x in range(width)] for y in range(height)]
        self.start_cell = self.cells[0][0] 
        self.exit_cell = self.cells[height-1][width-1] 
 
    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:
            neighbor = self.get_cell(cell.x + dx, cell.y + dy)
            if neighbor and neighbor.is_passable():
                neighbors.append(neighbor)
        return neighbors

# Строитель 
class MazeBuilder:
    def buildFromFile(self, filename):
        with open(filename, 'r') as f:
            lines = f.readlines()
        height = len(lines)
        width = len(lines[0].strip())
        maze = Maze(width, height)
        for y, line in enumerate(lines):
            for x, char in enumerate(line.strip()):
                cell = maze.get_cell(x, y)
                if char == '#': cell.is_wall = True
                elif char == 'S':
                    cell.is_start = True
                    maze.start_cell = cell
                elif char == 'E':
                    cell.is_exit = True
                    maze.exit_cell = cell
        if not maze.start_cell or not maze.exit_cell:
            raise ValueError("Лабиринт сломан")
        return maze


#  Strategy 
class PathFindingStrategy:
    def findPath(self, maze, start, exit):
        raise NotImplementedError("Этот метод должен быть реализован в стратегии!")

    def _reconstruct_path(self, parents, current):
        path = []
        while current:
            path.append(current)
            current = parents.get(current)
        return path[::-1]
class Command(ABC):
    @abstractmethod
    def execute(self): pass
    @abstractmethod
    def undo(self): pass

class MoveCommand(Command):
    def __init__(self, player, dx, dy, maze):
        self.player = player
        self.dx = dx
        self.dy = dy
        self.maze = maze
        self.prev_cell = None

    def execute(self):
        self.prev_cell = self.player.current_cell
        target = self.maze.get_cell(self.prev_cell.x + self.dx, self.prev_cell.y + self.dy)
        if target and target.is_passable():
            self.player.current_cell = target
            return True
        return False

    def undo(self):
        self.player.current_cell = self.prev_cell

class BFSStrategy(PathFindingStrategy):
    def findPath(self, maze, start, exit):
        queue = deque([start])
        parents = {start: None}
        start.visited = True
        while queue:
            current = queue.popleft()
            if current == exit:
                return self._reconstruct_path(parents, exit)
            for neighbor in maze.get_neighbors(current):
                if not neighbor.visited:
                    neighbor.visited = True
                    parents[neighbor] = current
                    queue.append(neighbor)
        return []

class AStarStrategy(PathFindingStrategy):
    def _heuristic(self, a, b):
        return abs(a.x - b.x) + abs(a.y - b.y)

    def findPath(self, maze, start, exit):
        heap = [(0, start)]
        parents = {start: None}
        g_score = {start: 0}
        while heap:
            _, current = heapq.heappop(heap)
            if current == exit:
                return self._reconstruct_path(parents, exit)
            for neighbor in maze.get_neighbors(current):
                new_g = g_score[current] + 1
                if new_g < g_score.get(neighbor, float('inf')):
                    parents[neighbor] = current
                    g_score[neighbor] = new_g
                    f = new_g + self._heuristic(neighbor, exit)
                    heapq.heappush(heap, (f, neighbor))
        return []

# Статистика 
class SearchStats:
    def __init__(self, time_ms, visited, length):
        self.time_ms = time_ms
        self.visited = visited
        self.length = length

# Паттерн Observer 
class Observer(ABC):
    @abstractmethod
    def update(self, event: str, data=None):
        pass

class ConsoleView(Observer):
    def update(self, event: str, data=None):
        if event == "path_found":
            print(f"Событие '{event}': время={data.time_ms:.2f}мс, посещено={data.visited}, путь={data.length}")
        elif event == "maze_loaded":
            print(f"Событие '{event}': Лабиринт загружен.")

# --- 6. Оркестратор (MazeSolver) ---
class MazeSolver:
    def __init__(self, maze, player):
        self.maze = maze
        self.player = player
        self.strat = None
        self._observers = []
        self._history = [] # Стек для undo

    def attach(self, observer):
        self._observers.append(observer)

    def notify(self, event, data=None):
        for obs in self._observers:
            obs.update(event, data)

    # Метод для ручного управления (Command)
    def move_player(self, dx, dy):
        cmd = MoveCommand(self.player, dx, dy, self.maze)
        if cmd.execute():
            self._history.append(cmd)
            self.notify("player_moved", self.player.current_cell)
        else:
            self.notify("error", "Стена!")

    def undo_move(self):
        if self._history:
            cmd = self._history.pop()
            cmd.undo()
            self.notify("player_moved", self.player.current_cell)

    

    def solve(self):
        if not self.strat: return None
        
        t0 = time.perf_counter()
        path = self.strat.findPath(self.maze, self.maze.start_cell, self.maze.exit_cell)
        t1 = time.perf_counter()
        
        visited_count = sum(c.visited for row in self.maze.cells for c in row)
        stats = SearchStats((t1 - t0) * 1000, visited_count, len(path))
        
        self.notify("path_found", stats)
        return stats

# --- Запуск ---
if __name__ == "__main__":
    maze = Maze(10, 10) 
    player = Player(maze.start_cell)
    solver = MazeSolver(maze, player)
    solver.attach(ConsoleView())

    solver.move_player(1, 0) 
    solver.undo_move()          
    
    print("Используйте WASD для движения, Z для отмены хода, Q для выхода")
while True:
    cmd = input("Введите команду: ").lower()
    if cmd == 'd': 
        solver.move_player(1, 0)
    elif cmd == 'a': 
        solver.move_player(-1, 0)
    elif cmd == 's': 
        solver.move_player(0, 1)
    elif cmd == 'w': 
        solver.move_player(0, -1)
    elif cmd == 'z': 
        solver.undo_move()
    elif cmd == 'q': 
        break