mcstatusface/src/status.rs

use std::io::{Error, ErrorKind, Read, Write, Result};
use std::net::{SocketAddr, TcpStream};

use crate::leb128::LEB128;

#[derive(serde::Serialize, serde::Deserialize)]
pub struct MinecraftVersion {
    pub name: String,
    pub protocol: u32,
}

#[derive(serde::Serialize, serde::Deserialize)]
pub struct MinecraftPlayer {
    pub name: String,
    pub id: String,
}

#[derive(serde::Serialize, serde::Deserialize)]
pub struct MinecraftPlayers {
    pub online: u32,
    pub max: u32,
    pub sample: Vec<MinecraftPlayer>,
}

#[derive(serde::Serialize, serde::Deserialize)]
#[serde(untagged)]
enum MinecraftDescriptionExtra {
    Extra(MinecraftDescription),
    String(String),
}

#[derive(serde::Serialize, serde::Deserialize)]
pub struct MinecraftDescription {
    text: String,
    extra: Option<Vec<MinecraftDescriptionExtra>>,
    bold: Option<bool>,
    color: Option<String>,
}

#[derive(serde::Serialize, serde::Deserialize)]
pub struct MinecraftStatus {
    pub version: MinecraftVersion,
    pub players: MinecraftPlayers,
    description: MinecraftDescription,
    pub favicon: Option<String>,
    #[serde(alias = "enforcesSecureChat")]
    enforces_secure_chat: Option<bool>,
}

impl MinecraftStatus {
    pub fn fetch(address: SocketAddr) -> Result<MinecraftStatus> {
        // println!("Connecting to {address}...");

        let mut stream = TcpStream::connect(address.to_string()).unwrap();
        // println!("Connected!");

        let mut send_buffer: Vec<u8> = Vec::new();

        // println!("Sending payload...");
        send_buffer.push(0x00);
        LEB128::write_leb128(&mut send_buffer, 769); // 1.21.4
        LEB128::write_leb128(&mut send_buffer, address.ip().to_string().len().try_into().unwrap());
        send_buffer.extend_from_slice(address.ip().to_string().as_bytes());
        send_buffer.extend_from_slice(&address.port().to_be_bytes());
        LEB128::write_leb128(&mut send_buffer, 1);
        send_packet(&mut stream, &send_buffer).unwrap();

        send_packet(&mut stream, &[0x00]).unwrap();

        let mut data: Vec<u8> = Vec::new();
        let mut len: usize = 0;
        let mut msg_len: usize = 0;
        let mut object_len: usize = 0;
        let mut offset: usize = 0;

        loop {
            let mut recv_buffer: [u8; 10240] = [0; 10240];
            len += stream.read(&mut recv_buffer)?;

            if len > 0 {
                if msg_len == 0 {
                    let mut val: u32;
                    (val, offset) = LEB128::read_leb128(&recv_buffer);
                    msg_len = val as usize;

                    if recv_buffer[offset] != 0x00 {
                        return Err(Error::new(ErrorKind::InvalidData, format!("Expected packet type 0x00, but got 0x{:02x?}!", recv_buffer[offset])));
                    }
                    offset += 1; // skip message type bit

                    let offset2: usize;
                    (val, offset2) = LEB128::read_leb128(&recv_buffer[offset..]);
                    object_len = val as usize;
                    offset += offset2;
                }
                data.extend_from_slice(&recv_buffer);
                if len >= offset + object_len {
                    break;
                }
            }
        }
        let msg = std::str::from_utf8(&data[offset..]).unwrap().trim();
        let sanitised: String = msg.chars().filter(|&c| c >= '\u{20}' || c == '\n' || c == '\r' || c == '\t').collect();
        // println!("{sanitised}");
        let status: MinecraftStatus = serde_json::from_slice(sanitised.as_bytes()).unwrap();

        Ok(status)
    }

    pub fn parse_description(&self) -> String {
        _description(&self.description)
    }

    pub fn enforces_secure_chat(&self) -> bool {
        self.enforces_secure_chat.unwrap_or(false)
    }
}

fn _description(description: &MinecraftDescription) -> String {
    if description.extra.is_some() {
        let mut extras = String::new();
        for extra in description.extra.as_ref().unwrap() {
            match extra {
                MinecraftDescriptionExtra::Extra(description) => {
                    extras += &_description(&description);
                }
                MinecraftDescriptionExtra::String(string) => {
                    extras += &string;
                }
            }
        }
        return description.text.clone() + &extras;
    }
    description.text.clone()
}

fn send_packet(stream: &mut TcpStream, data: &[u8]) -> Result<()> {
    let mut packet: Vec<u8> = Vec::new();
    LEB128::write_leb128(&mut packet, data.len() as u64);
    packet.extend_from_slice(&data);

    stream.write(&packet).unwrap();
    Ok(())
}