pub fn part_1(input: &str) -> u64 {
    let mut priorities_sum: u64 = 0;
    let backpacks = input.lines();

    for backpack in backpacks {
        // todo this should be .chars() or something
        let items: Vec<&str> = backpack.split("").collect();
        let items_per_compartment = items.len() / 2;
        let first_compartment = &items[1..items_per_compartment];
        let second_compartment= &items[items_per_compartment..(items.len() - 1)];

        for item in first_compartment {
            if second_compartment.contains(item) {
                let mut byte = item.as_bytes()[0] as u64;

                // this is kind of diabolical
                if item.to_string() == item.to_uppercase() {
                    byte -= 38;
                } else {
                    byte -= 96;
                }

                priorities_sum += byte;

                break;
            }
        }
    }

    priorities_sum
}