use std::io::Write;
use std::io::{stdin, stdout};

fn print_prompt() {
    print!("$ ");
    stdout().flush().unwrap();
}

pub fn get_user_input() -> Option<String> {
    print_prompt();

    let mut user_input = String::new();

    let bytes_read = stdin()
        .read_line(&mut user_input)
        .expect("error reading user input");

    match bytes_read {
        0 => None,
        _ => Some(user_input),
    }
}