use std::error::Error;
use std::fs::File;
use std::io::{self, BufRead};
use std::vec::Vec;

fn main() -> Result<(), Box<dyn Error>> {
    let file = File::open("inputs/day22.txt")?;
    let mut lines = io::BufReader::new(file).lines().map(|l| l.unwrap());

    lines.next();
    let mut deck1: Vec<u32> = Vec::new();
    while let Some(line) = lines.next() {
        if line == "" {
            break;
        }
        deck1.push(line.parse().expect("Unable to parse card number"));
    }

    lines.next();
    let mut deck2: Vec<u32> = Vec::new();
    while let Some(line) = lines.next() {
        if line == "" {
            break;
        }
        deck2.push(line.parse().expect("Unable to parse card number"));
    }

    while deck1.len() != 0 && deck2.len() != 0 {
        println!("Deck 1: {:?}", deck1);
        println!("Deck 2: {:?}", deck2);
        let card1 = deck1.remove(0);
        let card2 = deck2.remove(0);
        if card1 > card2 {
            println!("Player 1 wins");
            deck1.push(card1);
            deck1.push(card2);
        } else {
            println!("Player 2 wins");
            deck2.push(card2);
            deck2.push(card1);
        }
    }

    let winning_deck = if deck1.len() != 0 { deck1 } else { deck2 };
    let points = winning_deck
        .iter()
        .rev()
        .enumerate()
        .map(|(pos, card)| ((pos + 1) as u32) * card)
        .fold(0, |p, acc| p + acc);

    println!("Points: {}", points);

    Ok(())
}

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