//! Awful...

use std::{cmp::Ordering, collections::{HashMap, HashSet}, error::Error, fs::File, io::{BufRead, BufReader}};

fn main() -> Result<(), Box<dyn Error>> {
    let f = File::open("input/5.test")?;
    let mut f = BufReader::new(f);

    let mut must_precede: HashMap<i64, HashSet<i64>> = HashMap::new();
    let mut line = String::new();

    loop {
        line.clear();
        f.read_line(&mut line)?;
        let line = line.trim_end();
        if line.is_empty() { break };
        let (lhs, rhs) = line.split_once('|').ok_or("Invalid dependency line")?;
        must_precede.entry(lhs.parse()?).or_default().insert(rhs.parse()?);
    }

    let mut pages: Vec<i64> = Vec::new();
    let mut p1_total = 0;
    let mut p2_total = 0;

    loop {
        line.clear();
        if f.read_line(&mut line)? == 0 {
            break;
        };
        pages.clear();
        // Ugh...
        pages.extend(line.trim_end().split(',').map(|p| p.parse::<i64>().unwrap()));
        let mut valid = true;
        'outer: for (i, page) in pages.iter().enumerate().skip(1) {
            let Some(succ) = must_precede.get(page) else {
                continue;
            };
            for p in &pages[0..i] {
                if succ.contains(p) {
                    valid = false;
                    break 'outer;
                }
            }
        }
        if valid {
            p1_total += pages[pages.len() / 2];
        } else {
            pages.sort_by(|a, b| {
                if let Some(succ) = must_precede.get(a) {
                    if succ.contains(b) {
                        Ordering::Less
                    } else {
                        Ordering::Greater
                    }
                } else {
                    Ordering::Equal
                }
            });
            p2_total += pages[pages.len() / 2];
        }
    }
    println!("{p1_total}\n{p2_total}");
    Ok(())
}