rust_minecraft_server/src/server/player/helper.rs

use std::{
    io::Read,
    sync::Arc,
    time::{Duration, SystemTime},
};

use rust_mc_proto::{DataReader, DataWriter, Packet};

use crate::server::{
    ServerError,
    data::{ReadWriteNBT, text_component::TextComponent},
    protocol::{
        id::{clientbound, serverbound},
        *,
    },
};

use super::context::ClientContext;

// Помощник в работе с протоколом
// Может быть использован где угодно, но сделан именно для листенеров и пакет хандлеров
// Через него удобно делать всякую одинаковую херь
// Возможно надо было бы сделать прям обязательный какойто структ через который только можно было отправлять пакеты ...
// ... но мне лень
// Пусть юзают подключение и отправляют пакеты через него если хотят
// Почему бы и нет если да
pub struct ProtocolHelper {
    client: Arc<ClientContext>,
    state: ConnectionState,
}

impl ProtocolHelper {
    pub fn new(client: Arc<ClientContext>) -> Self {
        Self {
            state: client.state(),
            client,
        }
    }

    pub fn reset_chat(&self) -> Result<(), ServerError> {
        match self.state {
            ConnectionState::Configuration => {
                self.client
                    .write_packet(&Packet::empty(clientbound::configuration::RESET_CHAT))?;
                Ok(())
            }
            _ => Err(ServerError::UnexpectedState),
        }
    }

    pub fn store_cookie(&self, id: &str, data: &[u8]) -> Result<(), ServerError> {
        self.client.write_packet(&Packet::build(
            match self.state {
                ConnectionState::Configuration => clientbound::configuration::STORE_COOKIE,
                ConnectionState::Play => clientbound::play::STORE_COOKIE,
                _ => { return Err(ServerError::UnexpectedState) },
            },
            |p| {
                p.write_string(id)?;
                p.write_bytes(data)
            },
        )?)?;
        Ok(())
    }

    /// Leave from Configuration to Play state
    pub fn leave_configuration(&self) -> Result<(), ServerError> {
        match self.state {
            ConnectionState::Configuration => {
                self.client
                    .write_packet(&Packet::empty(clientbound::configuration::FINISH))?;
                self.client
                    .read_packet(serverbound::configuration::ACKNOWLEDGE_FINISH)?;
                self.client.set_state(ConnectionState::Play)?;
                Ok(())
            }
            _ => Err(ServerError::UnexpectedState),
        }
    }

    /// Enter to Configuration from Play state
    pub fn enter_configuration(&self) -> Result<(), ServerError> {
        match self.state {
            ConnectionState::Play => {
                self.client
                    .write_packet(&Packet::empty(clientbound::play::START_CONFIGURATION))?;
                self.client
                    .read_packet(serverbound::play::ACKNOWLEDGE_CONFIGURATION)?;
                self.client.set_state(ConnectionState::Configuration)?;
                Ok(())
            }
            _ => Err(ServerError::UnexpectedState),
        }
    }

    /// Enter to Configuration from Play state
    pub fn ping(&self) -> Result<Duration, ServerError> {
        match self.state {
            ConnectionState::Play => {
                let time = SystemTime::now();
                self.client
                    .write_packet(&Packet::empty(clientbound::play::PING))?;
                self.client.read_packet(serverbound::play::PONG)?;
                Ok(SystemTime::now().duration_since(time).unwrap())
            }
            ConnectionState::Configuration => {
                let time = SystemTime::now();
                self.client
                    .write_packet(&Packet::empty(clientbound::configuration::PING))?;
                self.client.read_packet(serverbound::configuration::PONG)?;
                Ok(SystemTime::now().duration_since(time).unwrap())
            }
            _ => Err(ServerError::UnexpectedState),
        }
    }

    pub fn disconnect(&self, reason: TextComponent) -> Result<(), ServerError> {
        let packet = match self.state {
            ConnectionState::Login => {
                let text = reason.as_json()?;
                Packet::build(0x00, |p| p.write_string(&text))?
            }
            ConnectionState::Configuration => {
                let mut packet = Packet::empty(0x02);
                packet.write_nbt(&reason)?;
                packet
            }
            ConnectionState::Play => {
                let mut packet = Packet::empty(0x1C);
                packet.write_nbt(&reason)?;
                packet
            }
            _ => {
                self.client.close();
                return Ok(());
            }
        };
        self.client.write_packet(&packet)?;
        Ok(())
    }

    /// Returns cookie content
    pub fn request_cookie(&self, id: &str) -> Result<Option<Vec<u8>>, ServerError> {
        match self.state {
            ConnectionState::Configuration => {
                let mut packet = Packet::empty(clientbound::configuration::COOKIE_REQUEST);
                packet.write_string(id)?;
                self.client.write_packet(&packet)?;

                let mut packet = self
                    .client
                    .read_packet(serverbound::configuration::COOKIE_RESPONSE)?;
                packet.read_string()?;
                let data = if packet.read_boolean()? {
                    let n = packet.read_usize_varint()?;
                    Some(packet.read_bytes(n)?)
                } else {
                    None
                };

                Ok(data)
            },
            ConnectionState::Play => {
                let mut packet = Packet::empty(clientbound::play::COOKIE_REQUEST);
                packet.write_string(id)?;
                self.client.write_packet(&packet)?;

                let mut packet = self
                    .client
                    .read_packet(serverbound::play::COOKIE_RESPONSE)?;
                packet.read_string()?;
                let data = if packet.read_boolean()? {
                    let n = packet.read_usize_varint()?;
                    Some(packet.read_bytes(n)?)
                } else {
                    None
                };

                Ok(data)
            }
            _ => Err(ServerError::UnexpectedState),
        }
    }

    /// Returns login plugin response - (message_id, payload)
    pub fn send_login_plugin_request(
        &self,
        id: i32,
        channel: &str,
        data: &[u8],
    ) -> Result<(i32, Option<Vec<u8>>), ServerError> {
        match self.state {
            ConnectionState::Login => {
                let mut packet = Packet::empty(clientbound::login::PLUGIN_REQUEST);
                packet.write_varint(id)?;
                packet.write_string(channel)?;
                packet.write_bytes(data)?;
                self.client.write_packet(&packet)?;

                let mut packet = self
                    .client
                    .read_packet(serverbound::login::PLUGIN_RESPONSE)?;
                let identifier = packet.read_varint()?;
                let data = if packet.read_boolean()? {
                    let mut data = Vec::new();
                    packet.get_mut().read_to_end(&mut data).unwrap();
                    Some(data)
                } else {
                    None
                };

                Ok((identifier, data))
            }
            _ => Err(ServerError::UnexpectedState),
        }
    }

    pub fn send_plugin_message(&self, channel: &str, data: &[u8]) -> Result<(), ServerError> {
        let mut packet = match self.state {
            ConnectionState::Configuration => {
                Packet::empty(clientbound::configuration::PLUGIN_MESSAGE)
            }
            ConnectionState::Play => Packet::empty(clientbound::play::PLUGIN_MESSAGE),
            _ => return Err(ServerError::UnexpectedState),
        };
        packet.write_string(channel)?;
        packet.write_bytes(data)?;
        self.client.write_packet(&packet)?;
        Ok(())
    }
}