mod helpers;

fn main() {
    let input = helpers::read_std_in();
    part1(input.clone());
    part2(input.clone());
}

fn part1(input: String) {
    let max = input.chars().count()-1;
    let mut total = 0i32;
    for (i, c) in input.chars().enumerate() {
        let tst_idx = get_compare_idx(i, 1, max);
        total += get_compare_result(c, input.chars().nth(tst_idx).unwrap());
    }
    println!("Part 1: {}", total);
}

fn part2(input: String) {
    let max = input.chars().count()-1;
    let mut total = 0i32;
    for (i, c) in input.chars().enumerate() {
        let tst_idx = get_compare_idx(i, (input.chars().count() / 2), max);
        total += get_compare_result(c, input.chars().nth(tst_idx).unwrap());
    }
    println!("Part 2: {}", total);
}

fn get_compare_idx(curr: usize, add: usize, max: usize) -> usize {
    let mut ret = curr + add;
    if ret > max {
        ret -= max+1;
    }
    return ret;
}

fn get_compare_result(c1: char, c2: char) -> i32 {
    if c1 != c2 {
        return 0;
    }
    match c1.to_digit(10) {
        Some(v) => {
            return v as i32;
        },
        None => 0,
    }
}