use regex::Regex;

static DAY: u8 = 3;

fn main() {
    let input = advent::read_lines(DAY);
    println!("{DAY}a: {}", sum_multiplications(&input, true));
    println!("{DAY}b: {}", sum_multiplications(&input, false));
}

fn sum_multiplications(input: &[String], ignore_do: bool) -> u32 {
    let re = Regex::new(r"(do)\(\)|(don't)\(\)|(mul)\(([0-9]{1,3}),([0-9]{1,3})\)").unwrap();

    let mut sum = 0;
    let mut muls_enabled = true;
    for line in input {
        for cap in re.captures_iter(line) {
            if cap.get(1).is_some() { // do
                muls_enabled = true;
            } else if cap.get(2).is_some() { // don't
                muls_enabled = false;
            } else if cap.get(3).is_some() { // mul
                if ignore_do || muls_enabled {
                    let f1 = cap[4].parse::<u32>().unwrap();
                    let f2 = cap[5].parse::<u32>().unwrap();
                    sum += f1 * f2;
                }
            }
        }
    }
    sum
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test() {
        let input = [
            "xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))"
        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
        assert_eq!(sum_multiplications(&input, true), 161);

        let input = [
            "xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))"
        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
        assert_eq!(sum_multiplications(&input, false), 48);
    }
}