package adventofcode;

import adventofcode.utils.Utils;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

public class Day8 {
    private static final int WIDTH = 25;
    private static final int HEIGHT = 6;

    public static void solve() {
        String input = Utils.getInput(8).get(0);

        int imageSize = WIDTH * HEIGHT;
        int layers = input.length() / imageSize;

        List<char[]> data = new ArrayList<>(layers);

        for(int c = 0 ; c < input.length() ; c += imageSize) {
            data.add(input.substring(c, c + imageSize).toCharArray());
        }

        System.out.println(part1(data));
        System.out.println(part2(data, imageSize, layers));
    }

    private static long part1(List<char[]> data) {
        char[] leastZeroes = data.stream()
                .min(Comparator.comparingInt(e -> frequency(e, '0'))).get();

        return frequency(leastZeroes, '1') * frequency(leastZeroes, '2');
    }

    private static String part2(List<char[]> data, int imageSize, int layers) {
        StringBuilder finalImage = new StringBuilder();

        for(int i = 0 ; i < imageSize ; i++) {
            for(int layer = 0 ; layer < layers ; layer++) {
                int colour = data.get(layer)[i];
                if(colour == '2') {
                    continue;
                }

                finalImage.append(colour == '0' ? " " : "X");
                break;
            }

            if(i % WIDTH == WIDTH - 1) {
                finalImage.append("\n");
            }
        }

        return finalImage.toString();
    }

    private static int frequency(char[] array, char number) {
        int n = 0;
        for(char c : array) {
            if(c == number) {
                n++;
            }
        }

        return n;
    }
}