use itertools::Itertools;
use std::{fs, io};

fn format_path(day_num: usize, file: &str) -> String {
    format!("data/day{day_num:02}/{file}")
}

pub fn read_string(day_num: usize, file: &str) -> io::Result<String> {
    Ok(fs::read_to_string(format_path(day_num, file))?)
}

pub fn split_lines<'a>(lines: &'a str) -> impl Iterator<Item = &'a str> + 'a {
    lines
        .split('\n')
        .with_position()
        .filter_map(|(pos, line)| match pos {
            itertools::Position::Last if line.is_empty() => None,
            _ => Some(line),
        })
}