use crate::utils::Result;

use super::packet::Packet;
use byteorder::{BigEndian, ByteOrder};

use tracing::{debug, error};

use serde_repr::*;

use crate::utils::*;

#[derive(Debug)]
pub struct Common<'a> {
    pub packet_id: u16,
    pub version: u8,
    // client's uuid
    pub id: &'a str,

    pub token: u64,

    pub ttl: u8,
    // packet type
    pub pc: PacketType,
    pub flags: u16,
}

impl<'a> Common<'a> {
    pub fn encode(&self) -> Vec<u8> {
        let mut result = vec![];
        result.extend_from_slice(&self.packet_id.to_be_bytes());
        encode_u8(&mut result, self.version);

        encode_buf_without_size(&mut result, &self.id.as_bytes(), 32);
        // result.extend_from_slice(self.id.as_bytes());
        result.extend_from_slice(&self.token.to_be_bytes());
        // encode_buf_with_size_1(&mut result, self.id.as_bytes());

        encode_u8(&mut result, self.ttl);

        encode_u16(&mut result, self.flags);

        let flag = self.pc.to_u8();
        encode_u8(&mut result, flag);

        result
    }

    pub fn from_slice(value: &'a [u8]) -> Result<(Common, &'a [u8])> {
        const id_len: usize = 32;
        const token_len: usize = 8;

        if value.len() < 7 + id_len + token_len {
            return Err("common header length error".into());
        }
        let packet_id = u16::from_be_bytes(value[0..2].try_into().unwrap());
        let version = value[2];

        let v1 = &value[3..3 + id_len];
        let mut id = match std::str::from_utf8(v1) {
            Ok(s) => s,
            Err(e) => return Err(SDLanError::ConvertError(e.to_string())),
        };
        // let id = u64::from_be_bytes(v1);
        id = id.trim_end_matches('\0');

        let token = u64::from_be_bytes(
            value[3 + id_len..3 + id_len + token_len]
                .try_into()
                .unwrap(),
        );

        let ttl = value[3 + id_len + token_len];
        let flags = BigEndian::read_u16(&value[4 + id_len + token_len..6 + id_len + token_len]);
        let pc = value[6 + id_len + token_len];

        let common = Self {
            packet_id,
            version,
            id,
            ttl,
            token,
            pc: pc.into(),
            flags: flags,
        };
        Ok((common, &value[7 + id_len + token_len..]))
    }

    pub fn from_old_common(cmn: &'a Common) -> Self {
        return Common {
            packet_id: cmn.packet_id,
            id: cmn.id,
            token: cmn.token,
            version: cmn.version,
            ttl: cmn.ttl,
            pc: cmn.pc,
            flags: cmn.flags,
        };
    }

    pub fn new(id: &'a str) -> Self {
        return Common {
            packet_id: 0,
            id,
            token: 0,
            version: 1,
            ttl: 2,
            pc: PacketType::PKTInvalid,
            flags: 0,
        };
    }
}

#[derive(Debug, PartialEq, Serialize_repr, Deserialize_repr, Copy, Clone)]
#[repr(u8)]
pub enum PacketType {
    PKTInvalid,
    // 向sn注册
    PKTRegisterSuper,
    // 数据转发
    PKTPacket,
    // 打洞消息
    PKTRegister,
    // 打洞消息ACK
    PKTRegisterACK,
    // RegisterSuperACK,
    PKTRegisterSuperACK,
    PKTRegisterSuperAcknowledge,
    PKTRegisterSuperNAK,
    PKTUnregisterSuper,

    // 客户端向服务端发送另一个客户端的信息
    PKTQueryPeer,
    // 服务端向客户端返回消息
    PKTPeerInfo,
    // sn send command to other sn or edges
    PKTCommand,
    PKTCommandResp,
}

impl std::convert::From<u8> for PacketType {
    fn from(value: u8) -> Self {
        match value {
            // 0 => Self::PacketInvalid,
            1 => Self::PKTRegisterSuper,
            2 => Self::PKTPacket,
            3 => Self::PKTRegister,
            4 => Self::PKTRegisterACK,
            5 => Self::PKTRegisterSuperACK,
            6 => Self::PKTRegisterSuperAcknowledge,
            7 => Self::PKTRegisterSuperNAK,
            8 => Self::PKTUnregisterSuper,
            9 => Self::PKTQueryPeer,
            10 => Self::PKTPeerInfo,
            11 => Self::PKTCommand,
            12 => Self::PKTCommandResp,
            _ => Self::PKTInvalid,
        }
    }
}

impl PacketType {
    pub fn to_u8(&self) -> u8 {
        match *self {
            Self::PKTInvalid => 0,
            Self::PKTRegisterSuper => 1,
            Self::PKTPacket => 2,
            Self::PKTRegister => 3,
            Self::PKTRegisterACK => 4,
            Self::PKTRegisterSuperACK => 5,
            Self::PKTRegisterSuperAcknowledge => 6,
            Self::PKTRegisterSuperNAK => 7,
            Self::PKTUnregisterSuper => 8,
            Self::PKTQueryPeer => 9,
            Self::PKTPeerInfo => 10,
            Self::PKTCommand => 11,
            Self::PKTCommandResp => 12,
        }
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn test_common_encode_and_decode() {
        use super::*;

        let id = "hello";
        let common = Common {
            packet_id: 0,
            version: 0,
            id,
            token: 0,
            ttl: 2,
            pc: 1.into(),
            flags: 0,
        };
        let value1 = common.encode();
        println!("value1.len: {}", value1.len());
        let (common2, _) = Common::from_slice(&value1).unwrap();
        println!("common2 = {:?}", common2);
        assert_eq!(common.id, common2.id);
        assert_eq!(common.version, common2.version);
        assert_eq!(common.ttl, common2.ttl);
        assert_eq!(common.pc, common2.pc);
        assert_eq!(common.flags, common2.flags);
    }
}

pub fn encode_packet_encrypted<T: serde::Serialize>(
    cmn: &Common,
    pkt: &T,
    header_pass: &[u8],
) -> Result<Vec<u8>> {
    let hdr = cmn.encode();
    let body = serde_json::to_vec(pkt)?;
    let body = aes_encrypt(header_pass, &body)?;

    let mut result = Vec::with_capacity(2 + hdr.len() + body.len());
    let total_size = (hdr.len() + body.len()) as u16;
    // insert total size
    result.extend_from_slice(&total_size.to_be_bytes());
    // packet_id
    // result.extend_from_slice(&[0, 0]);
    // insert header
    result.extend_from_slice(&hdr);
    // insert body
    result.extend_from_slice(&body);

    Ok(result)
}

/*
pub fn encode_packet_packet_encrypt(
    cmn: &Common,
    pkt: &Packet<'_>,
    header_pass: &[u8],
) -> Result<Vec<u8>> {
    let data2 = aes_encrypt(header_pass, pkt.data)?;
    pkt.data = &data2;
    encode_packet_packet(cmn, pkt)
}
*/

pub fn encode_packet_packet(cmn: &Common, pkt: &Packet<'_>) -> Result<Vec<u8>> {
    let hdr = cmn.encode();
    let body = pkt.marshal()?;

    let mut result = Vec::with_capacity(2 + hdr.len() + body.len());
    let total_size = (hdr.len() + body.len()) as u16;
    // insert total size
    result.extend_from_slice(&total_size.to_be_bytes());
    // packet_id
    // result.extend_from_slice(&[0, 0]);
    // insert header
    result.extend_from_slice(&hdr);
    // insert body
    result.extend_from_slice(&body);

    Ok(result)
}

pub fn encode_packet<T: serde::Serialize>(cmn: &Common, pkt: &T) -> Result<Vec<u8>> {
    // header
    let hdr = cmn.encode();
    // body
    let body = serde_json::to_vec(pkt)?;

    debug!(
        "body({}): {}",
        body.len(),
        std::str::from_utf8(&body).unwrap()
    );

    let mut result = Vec::with_capacity(2 + hdr.len() + body.len());
    let total_size = (hdr.len() + body.len()) as u16;
    // insert total size
    result.extend_from_slice(&total_size.to_be_bytes());
    // packet_id
    // result.extend_from_slice(&[0, 0]);
    // insert header
    result.extend_from_slice(&hdr);
    // insert body
    result.extend_from_slice(&body);

    debug!("enocded packet size: {}", result.len());
    // debug!("encoded packet: {:?}", result);

    Ok(result)
}

// decode the common, and return the encrypted bytes;
pub fn decode_common<'a>(value: &'a [u8]) -> Result<(Common<'a>, &'a [u8])> {
    if value.len() < 4 {
        return Err(SDLanError::NormalError("decode pkt length error"));
    }
    let size_bytes = value[0..2].try_into().expect("never goes here");
    let size = u16::from_be_bytes(size_bytes);
    if value.len() < 2 + size as usize {
        error!("decode pkt header error: {}: {}", value.len(), 2 + size);
        return Err(SDLanError::NormalError("decode pkt header size error"));
    }

    let value2 = &value[2..2 + size as usize];
    let Ok((cmn, value2)) = Common::from_slice(value2) else {
        error!("failed to decode common");
        return Err(SDLanError::NormalError("failed to deocde common"));
    };
    Ok((cmn, value2))
}

// decode the whole packet, suitable for un-encrypted packet info
pub fn decode_packet<'a, T: serde::Deserialize<'a>>(value: &'a [u8]) -> Result<(Common<'a>, T)> {
    // let value2 = &value[4..2 + size as usize];
    let (cmn, value2) = decode_common(value)?;
    // let (cmn, value2) = Common::from_slice(value2)?;
    let res = serde_json::from_slice(value2)?;
    Ok((cmn, res))
}