werewolves/werewolves-server/src/host.rs

// Copyright (C) 2025 Emilis Bliūdžius
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
use core::net::SocketAddr;

use axum::{
    extract::{
        ConnectInfo, State, WebSocketUpgrade,
        ws::{self, Message, WebSocket},
    },
    response::IntoResponse,
};
use axum_extra::{TypedHeader, headers};
use colored::Colorize;
use tokio::sync::{broadcast::Receiver, mpsc::Sender};
use werewolves_proto::message::host::{HostMessage, ServerToHostMessage};

use crate::{AppState, LogError, XForwardedFor};

pub async fn handler(
    ws: WebSocketUpgrade,
    user_agent: Option<TypedHeader<headers::UserAgent>>,
    x_forwarded_for: Option<TypedHeader<XForwardedFor>>,
    ConnectInfo(addr): ConnectInfo<SocketAddr>,
    State(state): State<AppState>,
) -> impl IntoResponse {
    let who = x_forwarded_for
        .map(|x| x.to_string())
        .unwrap_or_else(|| addr.to_string());
    log::info!(
        "{who}{} connected.",
        user_agent
            .map(|agent| format!(" (User-Agent: {})", agent.as_str()))
            .unwrap_or_default(),
    );

    // finalize the upgrade process by returning upgrade callback.
    // we can customize the callback by sending additional info such as address.
    ws.on_upgrade(move |socket| async move {
        Host::new(
            socket,
            state.host_send.clone(),
            state.host_recv.resubscribe(),
        )
        .run()
        .await
    })
}

struct Host {
    socket: WebSocket,
    host_send: Sender<HostMessage>,
    server_recv: Receiver<ServerToHostMessage>,
}

impl Host {
    pub fn new(
        socket: WebSocket,
        host_send: Sender<HostMessage>,
        server_recv: Receiver<ServerToHostMessage>,
    ) -> Self {
        Self {
            host_send,
            server_recv,
            socket,
        }
    }

    async fn on_recv(
        &mut self,
        msg: Option<Result<Message, axum::Error>>,
    ) -> Result<(), anyhow::Error> {
        #[cfg(not(feature = "cbor"))]
        let msg: HostMessage = serde_json::from_slice(
            &match msg {
                Some(Ok(msg)) => msg,
                Some(Err(err)) => return Err(err.into()),
                None => {
                    log::warn!("[host] no message");
                    return Ok(());
                }
            }
            .into_data(),
        )?;
        #[cfg(feature = "cbor")]
        let msg: HostMessage = {
            let bytes = match msg {
                Some(Ok(msg)) => msg.into_data(),
                Some(Err(err)) => return Err(err.into()),
                None => {
                    log::warn!("[host] no message");
                    return Ok(());
                }
            };
            let slice: &[u8] = &bytes;
            ciborium::from_reader(slice)?
        };
        log::debug!(
            "{} {}",
            "[host::incoming::message]".bold(),
            format!("{msg:?}").dimmed()
        );
        Ok(self.host_send.send(msg).await?)
    }

    async fn send_message(&mut self, msg: &ServerToHostMessage) -> Result<(), anyhow::Error> {
        Ok(self
            .socket
            .send(
                #[cfg(not(feature = "cbor"))]
                ws::Message::Text(serde_json::to_string(msg)?.into()),
                #[cfg(feature = "cbor")]
                ws::Message::Binary({
                    let mut bytes = Vec::new();
                    ciborium::into_writer(msg, &mut bytes)?;
                    bytes.into()
                }),
            )
            .await?)
    }

    pub async fn run(mut self) {
        loop {
            tokio::select! {
                msg = self.socket.recv() => {
                    if let Err(err) = self.on_recv(msg).await  {
                        log::error!("{} {err}", "[host::incoming]".bold());
                        return;
                    }
                },
                msg = self.server_recv.recv() => {
                    match msg {
                        Ok(msg) => {
                            if let Err(err) = self.send_message(&msg).await {
                                log::error!("{} {err}", "[host::outgoing]".bold())
                            }
                        },
                        Err(err) => {
                            log::error!("{} {err}", "[host::mpsc]".bold());
                            return;
                        }
                    }
                }
            };
        }
    }
}