import sys
import os

class GridPoint:
    def __init__(self, x, y):
        self.x = x
        self.y = y
        self.blocked = False
        self.is_start = False
        self.is_exit = False

    def can_step(self):
        return not self.blocked

class Labyrinth:
    def __init__(self, w, h):
        self.w = w
        self.h = h
        self.grid = [[GridPoint(x, y) for x in range(w)] for y in range(h)]
        self.start_point = None
        self.exit_point = None

    def get_point(self, x, y):
        if 0 <= x < self.w and 0 <= y < self.h:
            return self.grid[y][x]
        return None

    def set_point(self, x, y, typ):
        p = self.get_point(x, y)
        if not p:
            return
        if typ == 'wall':
            p.blocked = True
        elif typ == 'start':
            if self.start_point:
                self.start_point.is_start = False
            p.is_start = True
            p.blocked = False
            self.start_point = p
        elif typ == 'exit':
            if self.exit_point:
                self.exit_point.is_exit = False
            p.is_exit = True
            p.blocked = False
            self.exit_point = p
        elif typ == 'path':
            p.blocked = False

class MazeLoader:
    def load(self, filename):
        raise NotImplementedError

class TextMazeLoader(MazeLoader):
    def load(self, filename):
        with open(filename, 'r') as f:
            lines = [line.rstrip('\n') for line in f]
        h = len(lines)
        w = max(len(line) for line in lines) if h > 0 else 0
        start_cnt = 0
        exit_cnt = 0
        lab = Labyrinth(w, h)

        for y, line in enumerate(lines):
            for x, ch in enumerate(line):
                if ch == '#':
                    lab.set_point(x, y, 'wall')
                elif ch == 'S':
                    lab.set_point(x, y, 'start')
                    start_cnt += 1
                elif ch == 'E':
                    lab.set_point(x, y, 'exit')
                    exit_cnt += 1
                else:
                    lab.set_point(x, y, 'path')
        if start_cnt != 1 or exit_cnt != 1:
            raise ValueError(f"Need exactly one S and one E. Found S={start_cnt}, E={exit_cnt}")
        return lab

class TextView:
    def display(self, lab):
        os.system('cls' if os.name == 'nt' else 'clear')
        print("=" * (lab.w * 2 + 4))
        print("   LABYRINTH")
        print("=" * (lab.w * 2 + 4))
        for y in range(lab.h):
            print("  ", end='')
            for x in range(lab.w):
                p = lab.get_point(x, y)
                if p == lab.start_point:
                    print('S', end=' ')
                elif p == lab.exit_point:
                    print('E', end=' ')
                elif p.blocked:
                    print('#', end=' ')
                else:
                    print('.', end=' ')
            print()
        print("=" * (lab.w * 2 + 4))
        print("  S - start  E - exit  # - wall  . - path")

if __name__ == "__main__":
    loader = TextMazeLoader()
    lab = loader.load("maze/maze1.txt")
    view = TextView()
    view.display(lab)