use directories::UserDirs;
use ssh2::KnownHostFileKind;

use crate::{Session, SessionSource};

impl SessionSource for ssh2::Session {
    type Error = ssh2::Error;

    type Iter = Vec<Session>;

    fn sessions(&self) -> Result<Self::Iter, Self::Error> {
        let mut known_hosts = self.known_hosts()?;

        let file = UserDirs::new()
            .ok_or_else(ssh2::Error::unknown)?
            .home_dir()
            .join(".ssh/known_hosts");

        known_hosts.read_file(&file, KnownHostFileKind::OpenSSH)?;

        let sessions = known_hosts
            .hosts()?
            .into_iter()
            .filter_map(|h| match h.name() {
                Some(name) => Some(name.to_owned().into()),
                None => {
                    tracing::warn!("Invalid host: No plain text host name exists");
                    None
                }
            })
            .collect();

        Ok(sessions)
    }
}