use std::ops::Deref;

use tracing::{debug, info};

use crate::server::config::RepoDetails;

#[derive(Debug, derive_more::From, derive_more::Display)]
pub enum Error {
    UnableToOpenRepo(Box<gix::open::Error>),
    NoFetchRemoteFound,
    Connect(Box<gix::remote::connect::Error>),
    Fetch(String),
}
impl std::error::Error for Error {}

#[tracing::instrument(skip_all, fields(repo = %repo_details))]
pub fn fetch(repo_details: &RepoDetails) -> Result<(), Error> {
    // INFO: gitdir validate tests that the default fetch remote matches the configured remote
    let repository = gix::ThreadSafeRepository::open(repo_details.gitdir.deref())
        .map_err(Box::new)?
        .to_thread_local();
    debug!(?repository, "opened repo");
    let Some(remote) = repository.find_default_remote(gix::remote::Direction::Fetch) else {
        return Err(Error::NoFetchRemoteFound);
    };
    debug!(?remote, "fetch remote");

    remote
        .map_err(|e| Error::Fetch(e.to_string()))?
        .connect(gix::remote::Direction::Fetch)
        .map_err(Box::new)?
        .prepare_fetch(gix::progress::Discard, Default::default())
        .map_err(|e| Error::Fetch(e.to_string()))?
        .receive(gix::progress::Discard, &Default::default())
        .map_err(|e| Error::Fetch(e.to_string()))?;

    info!("fetched");

    Ok(())
}