use std::env::args;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;

fn get_data() -> (Vec<bool>, Vec<Vec<bool>>) {
    let path = args().nth(1).unwrap();
    let file = File::open(path).unwrap();

    let mut lines = BufReader::new(file).lines();

    let cypher = lines
        .next()
        .unwrap()
        .unwrap()
        .chars()
        .map(|c| c == '#')
        .collect();

    assert_eq!(lines.next().unwrap().unwrap(), "");

    let img = lines
        .map(|l| l
            .unwrap()
            .chars()
            .map(|c| c == '#')
            .collect())
        .collect();

    return (cypher, img);
}

fn enhance(img: &Vec<Vec<bool>>, outside: bool, cypher: &Vec<bool>) -> (Vec<Vec<bool>>, bool) {
    let rows = img.len();
    let cols = img[0].len();

    let mut result = vec![vec![false; cols + 2]; rows + 2];
    let mut i;

    for x in 0..cols+2 {
        i = if outside {0b111111111} else {0};
        for y in 0..rows+2 {
            i &= 0b111111;
            if y >= rows {
                i <<= 3;
                if outside {
                    i |= 0b111;
                }
            } else {
                for dx in [0, 1, 2].iter() {
                    i <<= 1;
                    if x + dx < 2 || x + dx >= cols + 2 {
                        if outside {
                            i |= 1;
                        }
                    } else if img[y][x + dx - 2] {
                        i |= 1;
                    }
                }
            }
            result[y][x] = cypher[i];
        }
    }

    let outside_i = if outside {0b111111111} else {0};
    return (result, cypher[outside_i]);
}

fn count(img: &Vec<Vec<bool>>) -> usize {
    return img
        .iter()
        .map(|row| row
            .iter()
            .filter(|b| **b)
            .count())
        .sum();
}

fn main() {
    let (cypher, mut img) = get_data();
    let mut outside = false;

    for i in 0..50 {
        let data = enhance(&img, outside, &cypher);
        img = data.0;
        outside = data.1;

        if i == 1 {
            println!("{}", count(&img));
        }
    }

    println!("{}", count(&img));
}