use std::path::{Path, PathBuf};

use walkdir::WalkDir;

// Returns an ordered list of relative paths for files inside a directory recursively.
pub fn list_files<P: AsRef<Path>>(dir_path: P) -> Result<Vec<PathBuf>, std::io::Error> {
    let mut files = vec![];
    let dir_path = dir_path.as_ref();
    if !dir_path.exists() {
        return Ok(files);
    }
    for entry in WalkDir::new(dir_path) {
        let entry = entry?;
        if entry.file_type().is_file() {
            let path = entry.path();
            let path = path.strip_prefix(dir_path).unwrap();
            let path = path.to_path_buf();
            files.push(path);
        }
    }
    files.sort();
    Ok(files)
}