from typing import Text, List, Dict, Iterable
from collections import Counter


class Layers(object):

    def __init__(self, width: int, height: int, data: List[int]):
        self.layers = []
        self.width = width
        self.height = height
        self.parse_encoded_data(data)

    def parse_encoded_data(self, data: List[int]):
        lines = [data[i:i+self.width] for i in range(0, len(data), self.width)]
        assert len(lines) % self.height == 0
        [self.layers.append(lines[i:i+self.height]) for i in range(0, len(lines), self.height)]

    def generate_histograms(self) -> Iterable[Dict[int, int]]:
        """Get a histogram of pixel values per layer."""
        for layer in self.layers:
            yield Counter([x for y in layer for x in y])

    def find_part_1(self):
        least_zeros = min(self.generate_histograms(), key=lambda x: x.get(0, 0))
        return least_zeros.get(1) * least_zeros.get(2)

    def decode_image(self):
        if not self.layers:
            return
        final_image = self.layers[0]
        for layer in self.layers[1:]:
            final_image = [[a if a != 2 else b for a, b in zip(x, y)] for x, y in zip(final_image, layer)]
        return final_image

def main():
    pixels = open("day8.data").readlines()[0].strip()
    layers = Layers(25, 6, [int(x) for x in pixels])

    print(layers.find_part_1())
    for x in layers.decode_image():
        print("".join(["X" if y else " " for y in x]))


if __name__ == '__main__':
    main()