import os,re,telnetlib
from collections import namedtuple

Dir = namedtuple("Dir", ["char", "dy", "dx"])
tn = telnetlib.Telnet()

class Maze:

    START = "S"
    END   = "E"
    WALL  = "#"
    PATH  = " "
    OPEN  = {PATH, END}  # map locations you can move to (not WALL or already explored)

    RIGHT = Dir("D",  0,  1)
    DOWN  = Dir("X",  1,  0)
    LEFT  = Dir("A",  0, -1)
    UP    = Dir("W", -1,  0)
    DIRS  = [RIGHT, DOWN, LEFT, UP]

    movelist = "";

    @classmethod
    def load_maze(cls, fname):
        with open(fname) as inf:
            lines = (line.rstrip("\r\n") for line in inf)
            maze  = [list(line) for line in lines]
        return cls(maze)

    def __init__(self, maze):
        self.maze = maze

    def __str__(self):
        return "\n".join(''.join(line) for line in self.maze)

    def find_start(self):
        for y,line in enumerate(self.maze):
            try:
                x = line.index("S")
                return y, x
            except ValueError:
                pass

        # not found!
        raise ValueError("Start location not found")

    def solve(self, y, x):
        if self.maze[y][x] == Maze.END:
            # base case - endpoint has been found
            return True
        else:
            # search recursively in each direction from here
            for dir in Maze.DIRS:
                ny, nx = y + dir.dy, x + dir.dx
                if self.maze[ny][nx] in Maze.OPEN:  # can I go this way?
                    if self.maze[y][x] != Maze.START: # don't overwrite Maze.START

                        self.maze[y][x] = dir.char  # mark direction chosen

                    if self.solve(ny, nx):          # recurse...
                        self.movelist += dir.char
                        return True                 # solution found!

            # no solution found from this location
            if self.maze[y][x] != Maze.START:       # don't overwrite Maze.START
                self.maze[y][x] = Maze.PATH         # clear failed search from map
            return False

def main():

    host = "bufferoverflow.disappointedmama.com"
    port = 9000

    tn.open(host, port)

    os.remove("test.txt")
    os.remove("checkback.txt");

    while True:
        line = tn.read_until("\n", 5)
        if ( "[]" ) not in line:
            break

        origLine = line;
        line = line.replace( "  ", " " ).replace( "[]", "#" ).replace( "<>", "S" ).replace( "######################################### #", "#########################################E#" )

        with open("test.txt", "a") as myfile:
            myfile.write(line)

        with open("checkback.txt", "a") as myfile:
            myfile.write(origLine)

    maze = Maze.load_maze("test.txt")

    print("Maze loaded:")
    print(maze)

    try:
        sy, sx = maze.find_start()
        print("solving...")
        if maze.solve(sy, sx):

            print(maze)
            print(maze.movelist.replace("X", "S")[::-1])


        else:
            print("no solution found")
    except ValueError:
        print("No start point found.")

if __name__=="__main__":
    main()