use std::{fs, io::Read};

pub mod prelude {
    pub use std::error::Error;
}

pub fn read_input(day: usize) -> String {
    let mut s = String::new();
    let path = if let Some(arg) = std::env::args().nth(1) {
        if arg == "-" {
            std::io::stdin().read_to_string(&mut s).unwrap();
            return s;
        }
        arg
    } else {
        format!("day{}/input", day)
    };
    fs::read_to_string(path).expect("Could not read input")
}