import lib

EXAMPLE = r"""
.|...\....
|.-.\.....
.....|-...
........|.
..........
.........\
..../.\\..
.-.-/..|..
.|....-|.\
..//.|....
"""

NEW = {
    '.': {
        'w': (0, -1, 'w'),
        'e': (0,  1, 'e'),
        's': (1,  0, 's'),
        'n': (-1, 0, 'n'),
    },
    '|': {
        'w': [(1, 0, 's'), (-1, 0, 'n')],
        'e': [(1, 0, 's'), (-1, 0, 'n')],
        's': (1,  0, 's'),
        'n': (-1, 0, 'n'),
    },
    '-': {
        's': [(0, -1, 'w'), (0, 1, 'e')],
        'n': [(0, -1, 'w'), (0, 1, 'e')],
        'e': (0,  1, 'e'),
        'w': (0, -1, 'w'),
    },
    '/': {
        's': (0, -1, 'w'),
        'n': (0, 1, 'e'),
        'e': (-1,  0, 'n'),
        'w': (1, 0, 's'),
    },
    '\\': {
        's': (0, 1, 'e'),
        'n': (0, -1, 'w'),
        'e': (1,  0, 's'),
        'w': (-1, 0, 'n'),
    },
}

def solve(lines: list[str], second=False):
    res = 0

    g = list(map(list, lines))

    rows = len(g)
    cols = len(g[0])

    if not second:
        starts = [(0, 0, 'e')]
    else:
        starts = [(r, 0, 'e') for r in range(rows)]
        starts += [(r, cols - 1, 'w') for r in range(rows)]
        starts += [(0, c, 's') for c in range(cols)]
        starts += [(rows - 1, c, 'n') for c in range(cols)]

    for start in starts:
        visited = set()
        beams = [start]
        while beams:
            b = beams.pop()
            row, col, d = b
            visited.add((row, col, d))

            f = g[row][col]
            new = NEW[f][d]
            if isinstance(new, tuple):
                r, c, nd = new
                nr = row + r
                nc = col + c
                if nr >= 0 and nc >= 0 and nr < rows and nc < cols:
                    if not (nr, nc, nd) in visited:
                        beams.append((nr, nc, nd))
            else:
                for r, c, nd in new:
                    nr = row + r
                    nc = col + c
                    if nr >= 0 and nc >= 0 and nr < rows and nc < cols:
                        if not (nr, nc, nd) in visited:
                            beams.append((nr, nc, nd))

        v = set([(r, c) for (r, c, _) in list(visited)])
        res = max(res, len(v))
    return res


def main():
    lines = lib.str_to_lines_no_empty(EXAMPLE)
    print("Example  1:", solve(lines))

    lines = lib.str_to_lines_no_empty(open("i16.txt").read())
    print("Solution 1:", solve(lines))

    lines = lib.str_to_lines_no_empty(EXAMPLE)
    print("Example  2:", solve(lines, True))

    lines = lib.str_to_lines_no_empty(open("i16.txt").read())
    print("Solution 2:", solve(lines, True))

if __name__ == "__main__":
    main()