#![allow(unused_imports)]
use crate::prelude::*;

pub type I = &'static str;
pub type O = u64;

fn _silver (data: I) -> O {
    let mut sum = 0;

    let mut data = data;

    while let Some(f) = data.find("mul(") {
        data = &data[f..];
        let start = 4;
        let Some(fin) = data.find(')') else { break };
        let inside = &data[start..fin];
        if let Some((left, right)) = inside.split_once(',') {
            if let Ok(left) = left.parse::<u64>() && let Ok(right) = right.parse::<u64>() {
                sum += left * right;
            } else {
                data = &data[start..];
                continue;
            }
        } else {
            data = &data[start..];
            continue;
        }
        data = &data[fin+1..];
    }
    sum
}

fn _gold (data: I) -> O {
    let mut sum = 0;
    let mut enabled = true;
    let mut data = data;

    loop {
        let mul = data.find("mul(").unwrap_or(usize::MAX);
        let _do = data.find("do()").unwrap_or(usize::MAX);
        let dont = data.find("don't()").unwrap_or(usize::MAX);

        if [mul, _do, dont].iter().all(|&e| e == usize::MAX) {
            break;
        }

        let next = mul.min(_do).min(dont);

        if next == mul {
            data = &data[next..];
            let start = 4;
            let Some(fin) = data.find(')') else { break };
            let inside = &data[start..fin];
            if let Some((left, right)) = inside.split_once(',') {
                if let Ok(left) = left.parse::<u64>() && let Ok(right) = right.parse::<u64>() {
                    if enabled {
                        sum += left * right;
                    }
                } else {
                    data = &data[start..];
                    continue;
                }
            } else {
                data = &data[start..];
                continue;
            }
            data = &data[fin+1..];
        } else if next == _do {
            enabled = true;
            data = &data[next+4..];
        } else if next == dont {
            enabled = false;
            data = &data[next+7..];
        }
    }
    sum
}

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

    fn read () -> &'static str {
        inc!(3)
    }

    #[test]
    fn silver () {
        let data = read();
        let ans = _silver(data);

        assert_eq!(ans, 181345830)
    }

    #[test]
    fn gold () {
        let data = read();
        let ans = _gold(data);

        assert_eq!(ans, 98729041)
    }
}