use std::net::TcpStream;
use std::path::PathBuf;

use ssh2::Session;

use crate::config::RemoteBackupConfig;
use crate::error;
use crate::error::AlbatrossError;
use crate::remote::{PathLocation, RemoteBackupSite};

/// SFTP Remote Site
pub struct SFTPBackup {
    /// SSH Session
    session: Session,
    /// Remote target directory
    target_dir: PathBuf,
    /// Number of backups to keep
    backups_to_keep: usize,
}

impl SFTPBackup {
    /// New SFTPBackup
    pub fn new(config: &RemoteBackupConfig) -> error::Result<Self> {
        let sftp_config = config
            .sftp
            .as_ref()
            .ok_or_else(|| AlbatrossError::RemoteConfigError("SFTP".to_string()))?;

        let tcp = TcpStream::connect(&sftp_config.server_addr)?;
        let mut sess = Session::new()?;
        sess.set_tcp_stream(tcp);
        sess.handshake().unwrap();

        if let Some(password) = &sftp_config.password {
            sess.userauth_password(&sftp_config.username, password)?;
        } else if let Some(key) = &sftp_config.private_key {
            let public_key = sftp_config.public_key.as_deref();
            sess.userauth_pubkey_file(&sftp_config.username, public_key, key, None)?;
        } else {
            return Err(AlbatrossError::NoSSHAuth);
        }

        Ok(Self {
            session: sess,
            target_dir: sftp_config.remote_dir.clone(),
            backups_to_keep: config.backups_to_keep as usize,
        })
    }
}

impl RemoteBackupSite for SFTPBackup {
    type FileType = PathLocation;

    fn backup_to_remote(&mut self, file: PathBuf) -> error::Result<()> {
        let remote_path = self.target_dir.join(file.file_name().unwrap());

        let mut local_file = std::fs::File::open(&file)?;

        let sftp = self.session.sftp()?;

        let mut remote_file = sftp.create(&remote_path)?;

        std::io::copy(&mut local_file, &mut remote_file)?;

        Ok(())
    }

    fn get_backups(&mut self) -> error::Result<Vec<Self::FileType>> {
        let files = self.session.sftp()?.readdir(&self.target_dir)?;
        Ok(files
            .into_iter()
            .filter_map(|(file, _)| Self::FileType::new(file))
            .collect())
    }

    fn remove_backup(&mut self, backup: Self::FileType) -> error::Result<()> {
        Ok(self.session.sftp()?.unlink(&*backup.location)?)
    }

    fn backups_to_keep(&self) -> usize {
        self.backups_to_keep
    }
}