lazymc/src/protocol.rs

use std::sync::Mutex;

use crate::types;

pub const STATUS_PACKET_ID_STATUS: i32 = 0;
pub const STATUS_PACKET_ID_PING: i32 = 1;

/// Client state.
// TODO: add encryption/compression state
#[derive(Debug, Default)]
pub struct Client {
    /// Current client state.
    pub state: Mutex<ClientState>,
}

impl Client {
    /// Get client state.
    pub fn state(&self) -> ClientState {
        *self.state.lock().unwrap()
    }

    /// Set client state.
    pub fn set_state(&self, state: ClientState) {
        *self.state.lock().unwrap() = state;
    }
}

#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum ClientState {
    /// Initial client state.
    Handshake,

    /// State to query server status.
    Status,

    /// State to login to server.
    Login,

    /// State for playing.
    Play,
}

impl ClientState {
    /// From state ID.
    pub fn from_id(id: i32) -> Option<Self> {
        match id {
            // 0 => Self::Handshake,
            1 => Some(Self::Status),
            2 => Some(Self::Login),
            // 2 => Self::Play,
            _ => None,
        }
    }

    /// Get state ID.
    pub fn to_id(self) -> i32 {
        match self {
            Self::Handshake => unimplemented!(),
            Self::Status => 1,
            Self::Login => 2,
            Self::Play => unimplemented!(),
        }
    }
}

impl Default for ClientState {
    fn default() -> Self {
        Self::Handshake
    }
}

/// Raw Minecraft packet.
///
/// Having a packet ID and a raw data byte array.
pub struct RawPacket {
    /// Packet ID.
    pub id: i32,

    /// Packet data.
    pub data: Vec<u8>,
}

impl RawPacket {
    /// Construct new raw packet.
    pub fn new(id: i32, data: Vec<u8>) -> Self {
        Self { id, data }
    }

    /// Decode packet from raw buffer.
    pub fn decode(mut buf: &[u8]) -> Result<Self, ()> {
        // Read length
        let (read, len) = types::read_var_int(buf)?;
        buf = &buf[read..][..len as usize];

        Self::decode_data(len, buf)
    }

    /// Decode packet from raw buffer without the length header.
    pub fn decode_data(len: i32, mut buf: &[u8]) -> Result<Self, ()> {
        // Read packet ID, select buf
        let (read, packet_id) = types::read_var_int(buf)?;
        buf = &buf[read..];

        Ok(Self::new(packet_id, buf.to_vec()))
    }

    /// Encode packet to raw buffer.
    pub fn encode(&self) -> Result<Vec<u8>, ()> {
        let mut data = types::encode_var_int(self.id)?;
        data.extend_from_slice(&self.data);

        let len = data.len() as i32;
        let mut packet = types::encode_var_int(len)?;
        packet.append(&mut data);

        return Ok(packet);
    }
}