"""Day 11."""
with open("input") as f:
    CHART = tuple(tuple(x) for x in f.read().rstrip().split("\n"))

EMPTY = 'L'
OCCUPIED = '#'
FLOOR = '.'
MIN = 0
MAX = len(CHART[0]) - 1


def clamp(num, minimium, maximium):
    """Clamp a number in between a range."""
    if num <= minimium:
        return minimium
    if num >= maximium:
        return maximium
    return num


def get_neighbours(x, y):
    """Get neighbour cords for a point."""
    pairs = set()
    for i in range(x - 1, x + 2):
        for j in range(y - 1, y + 2):
            pairs.add(
                (
                    clamp(i, MIN, MAX),
                    clamp(j, MIN, MAX)
                )
            )
    # Remove self
    pairs.remove((x, y))
    return pairs


def get_new_seat(seat, neighbours, occupied_limit):
    """Get the new seat."""
    occupied_sum = sum(1 if x == OCCUPIED else 0 for x in neighbours)
    if seat == EMPTY and not any(x == OCCUPIED for x in neighbours):
        return OCCUPIED
    elif seat == OCCUPIED and occupied_sum >= occupied_limit:
        return EMPTY
    else:
        return seat


def iterate_over_chart_part1(chart, p=False):
    """Iterate over a chart for part 1."""
    new_map = []
    for y, row in enumerate(chart):
        new_map.append([])
        for x, col in enumerate(row):
            seat = chart[y][x]
            neighbours = tuple(chart[pair[1]][pair[0]] for pair in get_neighbours(x, y))
            new_map[y].append(get_new_seat(seat, neighbours, 4))
    return new_map


def iterate_over_chart_part2(chart, p=False):
    """Iterate over a chart for part 2."""
    new_map = []
    for y, row in enumerate(chart):
        new_map.append([])
        for x, col in enumerate(row):
            seat = chart[y][x]
            neighbours = find_first_seat(x, y, chart)
            new_map[y].append(get_new_seat(seat, neighbours, 5))
    return new_map


def print_chart(chart):
    """Pretty print a chart."""
    for y in chart:
        line = ""
        for x in y:
            line += x
        print(line)


def are_equal(chart1, chart2):
    """Check if two charts are equal."""
    for idx, _ in enumerate(chart1):
        if chart1[idx] != chart2[idx]:
            return False
    return True

def count_occupied(chart):
    """Count occupied seats in a chart."""
    count = 0
    for row in chart:
        for x in row:
            if x == OCCUPIED:
                count += 1
    return count

# Part 1
initial = CHART
count = 0
while True:
    new_chart = iterate_over_chart_part1(initial)
    if are_equal(new_chart, initial):
        print(count_occupied(new_chart))
        print("done")
        break
    else:
        # print_chart(new_chart)
        print(count)
        count += 1
    initial = new_chart


def find_first_seat(x, y, chart):
    """Find the first seat."""
    seen_seats = []
    # print("top")
    for new_y in range(y - 1, MIN - 1, -1):
        seat = chart[new_y][x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("top right")
    for idx, new_y in enumerate(range(y - 1, MIN - 1, -1)):
        new_x = x + idx + 1
        if new_x > MAX:
            break
        seat = chart[new_y][new_x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("right")
    for idx in range(len(chart[y][x:]) - 1):
        new_x = x + idx + 1
        seat = chart[y][new_x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("down right")
    for idx, new_x in enumerate(range(x + 1, MAX + 1)):
        new_y = y + idx + 1
        if new_y > MAX:
            break
        seat = chart[new_y][new_x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("down")
    for new_y in range(y + 1, MAX + 1):
        seat = chart[new_y][x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("down left")
    for idx, new_x in enumerate(range(x - 1, MIN - 1, -1)):
        new_y = y + idx + 1
        if new_y > MAX:
            break
        seat = chart[new_y][new_x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("left")
    for idx in range(len(chart[y][:x + 1]) - 1):
        new_x = x - idx - 1
        seat = chart[y][new_x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    # print("top left")
    for idx, new_x in enumerate(range(x - 1, MIN - 1, -1)):
        new_y = y - idx - 1
        if new_y < MIN:
            break
        seat = chart[new_y][new_x]
        if seat in [OCCUPIED, EMPTY]:
            seen_seats.append(seat)
            break
    return seen_seats


# Part 2
initial = CHART
count = 0
while True:
    new_chart = iterate_over_chart_part2(initial)
    if are_equal(new_chart, initial):
        print(count_occupied(new_chart))
        print("done")
        break
    else:
        # print_chart(new_chart)
        print(count)
        count += 1
    initial = new_chart