use bytes::Bytes;
use bytes::{Buf, BytesMut};
use std::io;
use tokio_util::codec::Decoder;

use tokio_util::codec::Encoder;

use crate::protocol::tcp::{self};

/******************************************************************************
 * Encoder/Decoder trait
 ******************************************************************************/

#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Default)]
pub struct TcpCodec(());

impl TcpCodec {
    pub fn new() -> TcpCodec {
        TcpCodec(())
    }
}

impl Decoder for TcpCodec {
    type Item = BytesMut;
    type Error = io::Error;

    fn decode(&mut self, data: &mut BytesMut) -> Result<Option<BytesMut>, io::Error> {
        println!("TcpCodec->decode(), handle data len: {}", data.len());

        if data.len() < 20 {
            return Ok(None);
        } else {
            let parsed_tcp = tcp::parse_tcp(data);
            if let Ok((tcp_payload, tcp_header)) = parsed_tcp {
                println!("{:?}, Payload {}", tcp_header, tcp_payload.len());

                // skip the tcp header
                data.advance(tcp_header.data_offset.into());

                // TODO return Ok(Some(XXX))
                return Ok(None);
            } else {
                return Err(std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("Invalid TCP header"),
                ));
            }
        }
    }
}

impl Encoder<Bytes> for TcpCodec {
    type Error = io::Error;

    fn encode(&mut self, _data: Bytes, _buf: &mut BytesMut) -> Result<(), io::Error> {
        // TODO
        Ok(())
    }
}