use std::fs::read_to_string;
use std::time::Instant;

fn get_hash(data: &[u8]) -> u8 {
    let mut state: u16 = 0;
    for &c in data {
        state += c as u16;
        state *= 17;
        state &= 255;
    }
    state as u8
}

fn main() {
    let time_start = Instant::now();
    let input_str = read_to_string("input.txt").unwrap();
    let input_line = input_str.lines().next().unwrap();
    let time_start_no_io = Instant::now();
    // Task 1
    let mut sum1: u32 = 0;
    // Task 2
    let mut sum2: u32 = 0;
    // Rust is annoying
    const NEW_VEC: Vec<(&[u8], u8)> = vec![];
    let mut boxes: [Vec<(&[u8], u8)>; 256] = [NEW_VEC; 256];
    // Processing the input
    for str in input_line.split(',') {
        let bytes = str.as_bytes();
        // Task 1
        sum1 += get_hash(bytes) as u32;
        // Task 2
        if *bytes.last().unwrap() == b'-' {
            // Remove
            let label = &bytes[..bytes.len()-1];
            let hash = get_hash(label);
            let target_box = &mut boxes[hash as usize];
            if let Some(index) = target_box.iter().position(|(str, _)| *str == label ) {
                target_box.remove(index);
            }
        } else {
            // Insert / modify
            let focal = bytes.last().unwrap() - b'0';
            let label = &bytes[..bytes.len()-2];
            let hash = get_hash(label);
            let target_box = &mut boxes[hash as usize];
            if let Some(index) = target_box.iter().position(|(str, _)| *str == label ) {
                target_box[index] = (label, focal);
            } else {
                target_box.push((label, focal));
            }
        }
    }
    for (i, current_box) in boxes.iter().enumerate() {
        let box_value = i + 1;
        for (i, (_, focal)) in current_box.iter().enumerate() {
            sum2 += (box_value * (i + 1) * *focal as usize) as u32;
        }
    }
    let elapsed = time_start.elapsed().as_micros();
    let elapsed_no_io = time_start_no_io.elapsed().as_micros();
    println!("Time: {}us", elapsed);
    println!("Time without file i/o: {}us", elapsed_no_io);
    println!("Sum1: {}", sum1);
    println!("Sum2: {}", sum2);
}