AoC-2022/day2/src/step1.rs

use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;
use std::path::PathBuf;

use clap::Parser;

#[derive(Parser)]
struct Cli {
    filename: PathBuf,
}

fn main() {
    let cli = Cli::parse();
    let file = File::open(cli.filename).expect("Can't read file");
    let reader = BufReader::new(file);

    let mut score = 0;
    for line in reader.lines() {
        let line = line.unwrap();
        if line.is_empty() {
            continue;
        }
        let mut play = line.trim().split(" ");
        let their_play = play.next().unwrap();
        let my_play = play.next().unwrap();

        // A/X => Rock
        // B/Y => Paper
        // C/Z => Scissors
        match (their_play, my_play) {
            ("A", "Y") | ("B", "Z") | ("C", "X") => score += 6, // win
            ("A", "X") | ("B", "Y") | ("C", "Z") => score += 3, // draw
            _ => (),                                            // loss
        }

        match my_play {
            "Z" => score += 3,
            "Y" => score += 2,
            "X" => score += 1,
            _ => (),
        }
    }

    println!("Your score: {}", score);
}