#!/usr/bin/env python3

import sys


ENERGY = []


# direction given as tuple, e.g., (1,0) for right
def move_beam(x,y,d,grid):
    while True:
        if (x > len(grid[0])-1) or (x < 0) or (y > len(grid)-1) or (y < 0): break
        if d in ENERGY[x+y*len(grid[0])]: break
        ENERGY[x+y*len(grid[0])].append(d)
        tile = grid[y][x]
        if tile == '.':
            x, y = x+d[0], y+d[1]
        elif (tile == '-' and d[1] == 0) or (tile == '|' and d[0] == 0):
            x,y = x+d[0], y+d[1]
        elif tile == '\\':
            d = (d[1],d[0])
            x,y = x+d[0], y+d[1]
        elif tile == '/':
            d = (-d[1],-d[0])
            x,y = x+d[0], y+d[1]
        elif tile == '-':
            move_beam(x-1, y, (-1,0), grid)
            move_beam(x+1, y, (1,0), grid)
        elif tile == '|':
            move_beam(x, y-1, (0,-1), grid)
            move_beam(x, y+1, (0,1), grid)


def energize(x,y,d,grid):
    global ENERGY
    ENERGY = []
    for i in range(len(grid) * len(grid[0])):
        ENERGY.append([])
    move_beam(x,y,d,grid)
    return len(ENERGY) - ENERGY.count([])


if __name__ == '__main__':
    grid = [list(line.strip('\n')) for line in open(sys.argv[1])]
    res2 = 0
    for i in range(len(grid)):
        res2 = max(energize(0,i,(1,0),grid),res2)
    for i in range(len(grid[0])):
        res2 = max(energize(i,0,(0,1),grid),res2)
    for i in range(len(grid)):
        res2 = max(energize(len(grid)-1,i,(-1,0),grid),res2)
    for i in range(len(grid[0])):
        res2 = max(energize(i,len(grid[0])-1,(0,-1),grid),res2)

    # challenge 1
    res1 = str(energize(0,0,(1,0),grid))
    print(f"challenge 1:\n{res1}\n")

    # challenge 2
    res2 = str(res2)
    print(f"challenge 2:\n{res2}\n")