use std::path::{Path, PathBuf};
use sha1_smol::Digest;

pub trait Download {
    fn get_url(&self) -> &str;
    fn get_path(&self) -> &Path;
    fn get_expect_digest(&self) -> Option<Digest>;
    fn get_expect_size(&self) -> Option<usize>;

    fn always_redownload(&self) -> bool;
}

pub type DownloadJob = dyn Download + Sync + Send;

pub struct MultiDownloader<'j, 'js> {
    jobs: &'js [&'j DownloadJob],
    nhandles: usize
}

impl<'j, 'js> MultiDownloader<'j, 'js> {
    pub fn new(jobs: &'js [&'j DownloadJob]) -> MultiDownloader<'j, 'js> {
        Self::with_handles(jobs, 8)
    }

    pub fn with_handles(jobs: &'js [&'j DownloadJob], nhandles: usize) -> MultiDownloader<'j, 'js> {
        assert!(nhandles > 0);
        
        MultiDownloader {
            jobs, nhandles
        }
    }

    fn do_it(&self) {
        
    }
}