from lib import get_data, str_to_ints, add2
from d9 import Amp


DIRS = {1: (-1, 0), 2: (1, 0), 3: (0, -1), 4: (0, 1)}
PATH_REVERSED = {1: 2, 2: 1, 3: 4, 4: 3}


def print_field(fields, walls, pos):
    dim = 40
    for y in range(-dim, dim + 1):
        row = ""
        for x in range(-dim, dim + 1):
            if (y, x) == pos:
                row += "X"
            elif (y, x) in fields:
                row += "."
            elif (y, x) in walls:
                row += "|"
            else:
                row += " "
        print(row)


def part_1(data):
    xs = str_to_ints(data)
    a = Amp(xs)

    walls = set()
    pos = (0, 0)
    target = None
    dir = None
    path = []
    dir_cmds_for_pos = {pos: [1, 2, 3, 4]}

    while not a.done:
        if len(dir_cmds_for_pos[pos]) > 0:
            dir_cmd = dir_cmds_for_pos[pos].pop()
            dir = DIRS[dir_cmd]

            new_pos = add2(pos, dir)
            if new_pos in dir_cmds_for_pos:
                continue

            a.feed(dir_cmd)
            a.go()
            status = a.pop()

            if status == 0:
                walls.add(new_pos)
            elif status == 1:
                pos = new_pos
                path.append(dir_cmd)
            elif status == 2:
                pos = new_pos
                path.append(dir_cmd)
                target = pos

            if pos not in dir_cmds_for_pos:
                dir_cmds_for_pos[pos] = [1, 2, 3, 4]

        elif len(path) > 0:
            dir_cmd = PATH_REVERSED[path.pop()]
            dir = DIRS[dir_cmd]
            pos = add2(pos, dir)
            a.feed(dir_cmd)
            a.go()
            status = a.pop()
            assert status == 1 or status == 2
        elif target is not None:
            break
        else:
            break
    fields = set(dir_cmds_for_pos.keys())
    # print_field(fields, walls, pos)

    seen = set()
    to_visit = [(0, 0)]
    steps = 0
    while len(to_visit) > 0:
        new = []
        for current in to_visit:
            if current == target:
                print(steps)
            seen.add(current)
            for dir in DIRS.values():
                nb = add2(current, dir)
                if nb in fields and nb not in seen:
                    new.append(nb)
        to_visit = new
        steps += 1

    seen = set()
    to_visit = [target]
    steps = 0
    while len(to_visit) > 0:
        new = []
        for current in to_visit:
            seen.add(current)
            for dir in DIRS.values():
                nb = add2(current, dir)
                if nb in fields and nb not in seen:
                    new.append(nb)
        to_visit = new
        steps += 1
    print(steps - 1)


def main():
    data = get_data(__file__)
    part_1(data)


if __name__ == "__main__":
    main()