use std::{
    fs::File,
    io::{BufRead, BufReader},
};

fn main() -> () {
    let path = "input.txt";

    let input = File::open(path).unwrap();
    let buf = BufReader::new(input);

    let score: i32 = buf
        .lines()
        .map(|line| {
            let line = line.unwrap();
            let opponent: i32 = match &line[0..1] {
                "A" => 0,
                "B" => 1,
                "C" => 2,
                _ => panic!("Invalid input"),
            };
            match &line[2..3] {
                "X" => 0 + pick_score(opponent, -1),
                "Y" => 3 + pick_score(opponent, 0),
                "Z" => 6 + pick_score(opponent, 1),
                _ => panic!("Invalid input"),
            }
        })
        .sum();

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

fn pick_score(opponent: i32, outcome: i32) -> i32 {
    (opponent + outcome + 3) % 3 + 1
}