#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use std::fs::File;
use std::io::Read;

fn hash(s: &str) -> usize {
    let mut h: usize = 0;

    for b in s.bytes() {
        h = ((h + (b as usize)) * 17) % 256;
    }
    h
}

#[derive(Debug, PartialEq, Clone)]
struct Lens {
    name: String,
    h: usize,
    f: Option<usize>,
}

fn main() {
    // let filename = "in/day15.ref";
    let filename = "in/day15.pzl";

    let mut f = File::open(filename).expect("cannot open file");
    let mut content = String::new();
    f.read_to_string(&mut content).expect("cannot read file");
    let token = content.trim_end().split(',');

    let mut ls: Vec<Lens> = Vec::new();
    let mut res1: usize = 0;
    for t in token {
        res1 += hash(t);

        if t.contains('=') {
            let (n, f) = t.split_once('=').unwrap();
            ls.push(Lens {
                name: n.to_owned(),
                h: hash(n),
                f: Some(f.parse().unwrap()),
            });
        } else {
            let n = t.trim_end_matches('-');
            ls.push(Lens {
                name: n.to_owned(),
                h: hash(n),
                f: None,
            });
        }
    }

    let mut hm: Vec<Vec<Lens>> = vec![[].to_vec(); 256];
    for l in ls {
        if let Some(f) = l.f {
            let mut found = false;
            for ll in 0..hm[l.h].len() {
                if hm[l.h][ll].name == l.name {
                    hm[l.h][ll].f = l.f;
                    found = true;
                    break;
                }
            }
            if !found {
                hm[l.h].push(l);
            }
        } else {
            hm[l.h].retain(|x| x.name != l.name);
        }
    }

    let mut res2 = 0;
    for b in 0..hm.len() {
        for l in 0..hm[b].len() {
            res2 += (b + 1) * (l + 1) * hm[b][l].f.unwrap();
        }
    }

    println!("res1: {}", res1);
    println!("res2: {}", res2);
    assert_eq!(res1, 506437);
    assert_eq!(res2, 288521);
}