use std::collections::HashMap;
use std::fs::File;
use std::io::{self, BufRead};
use std::path::Path;
use std::path::PathBuf;

pub fn load_groups(path: &PathBuf) -> io::Result<HashMap<String, Vec<String>>> {
    let lines = read_lines(path)?;
    let mut groups = HashMap::new();
    let mut group_name = String::new();
    for mut line in lines.map_while(Result::ok) {
        line.truncate(line.trim_end().len());
        if line.starts_with("#") || line.is_empty() {
            continue;
        }
        if line.starts_with("[") && line.ends_with("]") {
            group_name = line[1..line.len() - 2].to_string();
            if !groups.contains_key(&group_name) {
                groups.insert(group_name.clone(), vec![]);
            }
            continue;
        }
        if group_name.is_empty() {
            groups.insert(group_name.clone(), vec![]);
        }
        groups.get_mut(&group_name).unwrap().push(line);
    }
    Ok(groups)
}

fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
where
    P: AsRef<Path>,
{
    let file = File::open(filename)?;
    Ok(io::BufReader::new(file).lines())
}