use std::fs;
use std::io::{self, BufRead};

fn badge_find(items: &[u8]) -> u64 {
    items
        .iter()
        .fold(0, |badge, &item| badge | 1 << (item - 64))
}

fn repetition_find(items: &[u8]) -> u32 {
    let len = items.len() / 2;
    let left_pack = &items[..len];
    let right_pack = &items[len..];
    let (mut left, mut right) = (0u64, 0u64);
    let mut total = 0;

    for i in 0..len {
        left |= 1 << left_pack[i] - 64;
        right |= 1 << right_pack[i] - 64;
        let cross = left & right;
        if cross > 0 {
            total += priority(cross);
            break;
        }
    }
    total
}
fn priority(item: u64) -> u32 {
    let item = item.trailing_zeros();
    if item < 32 {
        item + 26
    } else {
        item - 32
    }
}

fn solve_prio() -> u32 {
    let file = fs::File::open("input").unwrap();
    let lines = io::BufReader::new(file).lines();
    let mut total = 0;
    for line in lines {
        total += repetition_find(line.unwrap().as_bytes());
    }
    total
}
fn solve_badge() -> u32 {
    let file = fs::File::open("input").unwrap();
    let lines = io::BufReader::new(file).lines();
    let mut total = 0;
    let mut badge = u64::MAX;
    let mut grouper = 0;

    for line in lines {
        let items = line.unwrap();
        badge &= badge_find(items.as_bytes());
        grouper += 1;
        if grouper % 3 == 0 {
            total += priority(badge);
            badge = u64::MAX;
        }
    }
    total
}
fn main() {
    assert_eq!(8072, solve_prio());
    assert_eq!(2567, solve_badge());
    println!("All test passed.")
}