missiond-core 0.1.0

//! WebSocket Server implementation
//!
//! Compatible with the Node implementation:
//! - PTY attach: `ws://host:port/pty/<slotId>`
//! - Tasks events: `ws://host:port/tasks`
//!
//! Messages (PTY):
//! - { type: "screen", data: string }
//! - { type: "data", data: string }
//! - { type: "state", state: string, prevState: string }
//! - { type: "exit", code: number }

use crate::cc_tasks::{CCTask, CCTaskChangeEvent, CCTasksOverview, CCTasksWatcher, WatcherEvent};
use crate::pty::{PTYManager, SessionEvent, SessionState};
use futures_util::{SinkExt, StreamExt};
use serde::{Deserialize, Serialize};
use std::net::SocketAddr;
use std::sync::{Arc, Mutex as StdMutex};
use tokio::net::{TcpListener, TcpStream};
use tokio::sync::{broadcast, Mutex};
use tokio_tungstenite::tungstenite::handshake::server::{Request as WsRequest, Response as WsResponse};
use tokio_tungstenite::tungstenite::protocol::frame::coding::CloseCode;
use tokio_tungstenite::tungstenite::protocol::CloseFrame;
use tokio_tungstenite::{accept_hdr_async, tungstenite::Message};
use tracing::{error, info, warn};

/// WebSocket server options
pub struct WSServerOptions {
    /// Server port
    pub port: u16,
    /// PTY manager (optional, for PTY attach)
    pub pty_manager: Option<Arc<PTYManager>>,
    /// CC Tasks watcher (optional, for tasks events)
    pub cc_tasks_watcher: Option<Arc<Mutex<CCTasksWatcher>>>,
}

/// PTY WebSocket Server
pub struct PTYWebSocketServer {
    port: u16,
    pty_manager: Option<Arc<PTYManager>>,
    cc_tasks_watcher: Option<Arc<Mutex<CCTasksWatcher>>>,
    shutdown_tx: Option<broadcast::Sender<()>>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum Route<'a> {
    Pty { slot_id: &'a str },
    Tasks,
    Invalid,
}

fn parse_route(path: &str) -> Route<'_> {
    if path == "/tasks" {
        return Route::Tasks;
    }
    if let Some(slot_id) = path.strip_prefix("/pty/") {
        if !slot_id.is_empty() && !slot_id.contains('/') {
            return Route::Pty { slot_id };
        }
    }
    Route::Invalid
}

fn close_frame(code: u16, reason: impl Into<String>) -> CloseFrame<'static> {
    CloseFrame {
        code: CloseCode::from(code),
        reason: reason.into().into(),
    }
}

async fn send_json<S: Serialize>(
    ws_tx: &mut futures_util::stream::SplitSink<tokio_tungstenite::WebSocketStream<TcpStream>, Message>,
    msg: &S,
) -> anyhow::Result<()> {
    let text = serde_json::to_string(msg)?;
    ws_tx.send(Message::Text(text)).await?;
    Ok(())
}

/// Messages from PTY to client
#[derive(Debug, Serialize)]
#[serde(tag = "type", rename_all = "lowercase")]
enum PtyOutMessage {
    Screen { data: String },
    Data { data: String },
    State {
        state: SessionState,
        #[serde(rename = "prevState")]
        prev_state: SessionState,
    },
    Exit { code: i32 },
}

/// Messages from client to PTY
#[derive(Debug, Deserialize)]
#[serde(tag = "type", rename_all = "lowercase")]
enum PtyInMessage {
    Input { data: String },
}

/// CC Tasks event messages
#[derive(Debug, Serialize)]
#[serde(tag = "type", rename_all = "snake_case")]
enum TasksEventMessage {
    CcTasksOverview { payload: CCTasksOverview },
    CcTasksChanged { payload: CCTaskChangeEvent },
    CcTaskStarted { payload: TaskEventPayload },
    CcTaskCompleted { payload: TaskEventPayload },
    CcSessionActive { payload: SessionEventPayload },
    CcSessionInactive { payload: SessionEventPayload },
}

#[derive(Debug, Serialize)]
#[serde(rename_all = "camelCase")]
struct TaskEventPayload {
    session_id: String,
    project_name: String,
    task: CCTask,
}

#[derive(Debug, Serialize)]
#[serde(rename_all = "camelCase")]
struct SessionEventPayload {
    session_id: String,
    project_name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    summary: Option<String>,
}

impl PTYWebSocketServer {
    /// Create a new WebSocket server
    pub fn new(options: WSServerOptions) -> Self {
        Self {
            port: options.port,
            pty_manager: options.pty_manager,
            cc_tasks_watcher: options.cc_tasks_watcher,
            shutdown_tx: None,
        }
    }

    /// Start the server
    pub async fn start(&mut self) -> anyhow::Result<()> {
        let addr = format!("0.0.0.0:{}", self.port);
        let listener = TcpListener::bind(&addr).await?;

        info!(port = self.port, "PTY WebSocket server started");

        let (shutdown_tx, _) = broadcast::channel::<()>(1);
        self.shutdown_tx = Some(shutdown_tx.clone());

        let pty_manager = self.pty_manager.clone();
        let cc_tasks_watcher = self.cc_tasks_watcher.clone();

        tokio::spawn(async move {
            let mut shutdown_rx = shutdown_tx.subscribe();
            loop {
                tokio::select! {
                    result = listener.accept() => {
                        match result {
                            Ok((stream, addr)) => {
                                let pty_manager = pty_manager.clone();
                                let cc_tasks_watcher = cc_tasks_watcher.clone();
                                tokio::spawn(async move {
                                    if let Err(e) = Self::handle_connection(stream, addr, pty_manager, cc_tasks_watcher).await {
                                        error!(?e, ?addr, "WebSocket connection error");
                                    }
                                });
                            }
                            Err(e) => {
                                error!(?e, "Failed to accept connection");
                            }
                        }
                    }
                    _ = shutdown_rx.recv() => {
                        info!("WebSocket server shutting down");
                        break;
                    }
                }
            }
        });

        Ok(())
    }

    /// Stop the server
    pub async fn stop(&mut self) {
        if let Some(tx) = self.shutdown_tx.take() {
            let _ = tx.send(());
        }
        info!("PTY WebSocket server stopped");
    }

    async fn handle_connection(
        stream: TcpStream,
        addr: SocketAddr,
        pty_manager: Option<Arc<PTYManager>>,
        cc_tasks_watcher: Option<Arc<Mutex<CCTasksWatcher>>>,
    ) -> anyhow::Result<()> {
        // Capture path from handshake
        let path_cell = Arc::new(StdMutex::new(String::new()));
        let path_cell2 = Arc::clone(&path_cell);

        let ws_stream = accept_hdr_async(stream, move |req: &WsRequest, resp: WsResponse| {
            if let Ok(mut path) = path_cell2.lock() {
                *path = req.uri().path().to_string();
            }
            Ok(resp)
        })
        .await?;

        let path = path_cell
            .lock()
            .map(|p| p.clone())
            .unwrap_or_else(|_| "/".to_string());

        match parse_route(&path) {
            Route::Tasks => Self::handle_tasks_subscription(addr, ws_stream, cc_tasks_watcher).await,
            Route::Pty { slot_id } => {
                Self::handle_pty_subscription(addr, ws_stream, pty_manager, slot_id).await
            }
            Route::Invalid => {
                let (mut ws_tx, _ws_rx) = ws_stream.split();
                let _ = ws_tx
                    .send(Message::Close(Some(close_frame(
                        4000,
                        "Invalid URL. Use /pty/<slotId> or /tasks",
                    ))))
                    .await;
                warn!(?addr, %path, "Invalid WebSocket URL");
                Ok(())
            }
        }
    }

    async fn handle_pty_subscription(
        addr: SocketAddr,
        ws_stream: tokio_tungstenite::WebSocketStream<TcpStream>,
        pty_manager: Option<Arc<PTYManager>>,
        slot_id: &str,
    ) -> anyhow::Result<()> {
        let pty_manager = match pty_manager {
            Some(pm) => pm,
            None => {
                let (mut ws_tx, _ws_rx) = ws_stream.split();
                let _ = ws_tx
                    .send(Message::Close(Some(close_frame(
                        4000,
                        "PTY manager not available",
                    ))))
                    .await;
                warn!(?addr, "PTY manager not available");
                return Ok(());
            }
        };

        // Check if PTY session exists
        let status = pty_manager.get_status(slot_id).await;
        if status
            .as_ref()
            .map(|s| s.state == SessionState::Exited)
            .unwrap_or(true)
        {
            let (mut ws_tx, _ws_rx) = ws_stream.split();
            let _ = ws_tx
                .send(Message::Close(Some(close_frame(
                    4001,
                    format!("PTY session not found: {}", slot_id),
                ))))
                .await;
            warn!(?addr, slot_id, "PTY session not found");
            return Ok(());
        }

        let (mut ws_tx, mut ws_rx) = ws_stream.split();

        info!(?addr, slot_id, "Client attached to PTY");

        // Send current screen content first
        if let Ok(screen) = pty_manager.get_screen(slot_id).await {
            let msg = PtyOutMessage::Screen { data: screen };
            let _ = send_json(&mut ws_tx, &msg).await;
        }

        // Subscribe to session events
        let mut session_rx = match pty_manager.subscribe_session(slot_id).await {
            Ok(rx) => rx,
            Err(e) => {
                warn!(?addr, slot_id, error = %e, "Cannot subscribe to PTY events");
                let _ = ws_tx
                    .send(Message::Close(Some(close_frame(
                        4002,
                        format!("Cannot attach to PTY: {}", slot_id),
                    ))))
                    .await;
                return Ok(());
            }
        };

        loop {
            tokio::select! {
                // PTY -> client
                evt = session_rx.recv() => {
                    let evt = match evt {
                        Ok(e) => e,
                        Err(_) => break,
                    };

                    match evt {
                        SessionEvent::Data(bytes) => {
                            let data = String::from_utf8_lossy(&bytes).to_string();
                            let msg = PtyOutMessage::Data { data };
                            if send_json(&mut ws_tx, &msg).await.is_err() {
                                break;
                            }
                        }
                        SessionEvent::StateChange { new_state, prev_state } => {
                            let msg = PtyOutMessage::State { state: new_state, prev_state };
                            if send_json(&mut ws_tx, &msg).await.is_err() {
                                break;
                            }
                        }
                        SessionEvent::Exit(code) => {
                            let msg = PtyOutMessage::Exit { code };
                            let _ = send_json(&mut ws_tx, &msg).await;
                            let _ = ws_tx.send(Message::Close(Some(close_frame(4003, format!("PTY exited with code {}", code))))).await;
                            break;
                        }
                        _ => {}
                    }
                }

                // client -> PTY
                msg = ws_rx.next() => {
                    match msg {
                        Some(Ok(Message::Text(text))) => {
                            if let Ok(input) = serde_json::from_str::<PtyInMessage>(&text) {
                                match input {
                                    PtyInMessage::Input { data } => {
                                        let _ = pty_manager.write(slot_id, &data).await;
                                    }
                                }
                            } else {
                                // Raw input fallback
                                let _ = pty_manager.write(slot_id, &text).await;
                            }
                        }
                        Some(Ok(Message::Binary(data))) => {
                            let text = String::from_utf8_lossy(&data).to_string();
                            let _ = pty_manager.write(slot_id, &text).await;
                        }
                        Some(Ok(Message::Close(_))) | None => break,
                        Some(Err(e)) => {
                            warn!(?addr, slot_id, error = %e, "WebSocket error");
                            break;
                        }
                        _ => {}
                    }
                }
            }
        }

        info!(?addr, slot_id, "Client disconnected from PTY");
        Ok(())
    }

    async fn handle_tasks_subscription(
        addr: SocketAddr,
        ws_stream: tokio_tungstenite::WebSocketStream<TcpStream>,
        cc_tasks_watcher: Option<Arc<Mutex<CCTasksWatcher>>>,
    ) -> anyhow::Result<()> {
        let watcher = match cc_tasks_watcher {
            Some(w) => w,
            None => {
                let (mut ws_tx, _ws_rx) = ws_stream.split();
                let _ = ws_tx
                    .send(Message::Close(Some(close_frame(
                        4000,
                        "CC Tasks watcher not available",
                    ))))
                    .await;
                warn!(?addr, "CC Tasks watcher not available");
                return Ok(());
            }
        };

        let (mut ws_tx, mut ws_rx) = ws_stream.split();

        info!(?addr, "Client subscribing to Tasks events");

        // Send current overview on connect
        let overview = watcher.lock().await.get_overview().await;
        let msg = TasksEventMessage::CcTasksOverview { payload: overview };
        let _ = send_json(&mut ws_tx, &msg).await;

        // Subscribe to watcher events
        let mut events_rx = watcher.lock().await.subscribe();

        loop {
            tokio::select! {
                event = events_rx.recv() => {
                    let event = match event {
                        Ok(e) => e,
                        Err(_) => break,
                    };

                    let msg = match event {
                        WatcherEvent::TasksChanged(e) => TasksEventMessage::CcTasksChanged { payload: e },
                        WatcherEvent::TaskStarted { session, task } => TasksEventMessage::CcTaskStarted {
                            payload: TaskEventPayload {
                                session_id: session.session_id,
                                project_name: session.project_name,
                                task,
                            }
                        },
                        WatcherEvent::TaskCompleted { session, task } => TasksEventMessage::CcTaskCompleted {
                            payload: TaskEventPayload {
                                session_id: session.session_id,
                                project_name: session.project_name,
                                task,
                            }
                        },
                        WatcherEvent::SessionActive(session) => TasksEventMessage::CcSessionActive {
                            payload: SessionEventPayload {
                                session_id: session.session_id,
                                project_name: session.project_name,
                                summary: Some(session.summary),
                            }
                        },
                        WatcherEvent::SessionInactive(session) => TasksEventMessage::CcSessionInactive {
                            payload: SessionEventPayload {
                                session_id: session.session_id,
                                project_name: session.project_name,
                                summary: None,
                            }
                        },
                    };

                    if send_json(&mut ws_tx, &msg).await.is_err() {
                        break;
                    }
                }

                msg = ws_rx.next() => {
                    match msg {
                        Some(Ok(Message::Close(_))) | None => break,
                        Some(Err(e)) => {
                            warn!(?addr, error = %e, "WebSocket error");
                            break;
                        }
                        _ => {}
                    }
                }
            }
        }

        info!(?addr, "Client unsubscribed from Tasks events");
        Ok(())
    }
}