codive-relay 0.1.0

//! Tunnel connection management

use codive_tunnel::{DataMessage, WireMessage};
use anyhow::Result;
use chrono::{DateTime, Utc};
use dashmap::DashMap;
use tokio::sync::{mpsc, oneshot, RwLock};

/// WebSocket message wrapper to distinguish between text and binary
#[derive(Debug, Clone)]
pub enum WsMessage {
    /// Text message (for control messages like Welcome, Ping, Pong)
    Text(String),
    /// Binary message (for encrypted data)
    Binary(Vec<u8>),
}

/// Sender type for WebSocket messages
pub type WsSender = mpsc::Sender<WsMessage>;

/// Response sender type - either oneshot for single responses or mpsc for streaming
pub enum ResponseSender {
    /// Single response (normal HTTP requests)
    Single(oneshot::Sender<DataMessage>),
    /// Streaming responses (SSE)
    Streaming(mpsc::Sender<DataMessage>),
}

/// A pending HTTP request waiting for a response
pub struct PendingRequest {
    /// Channel to send the response back
    pub response_tx: ResponseSender,
    /// Request timestamp for timeout tracking
    pub started_at: DateTime<Utc>,
    /// Is this a streaming request?
    pub is_streaming: bool,
}

/// Represents an active tunnel connection from a local agent
pub struct TunnelConnection {
    /// Unique tunnel identifier
    pub tunnel_id: String,
    /// WebSocket sender for sending messages to the agent
    pub ws_sender: WsSender,
    /// Pending HTTP requests awaiting responses
    pub pending_requests: DashMap<String, PendingRequest>,
    /// Creation timestamp
    pub created_at: DateTime<Utc>,
    /// Last activity timestamp
    pub last_activity: RwLock<DateTime<Utc>>,
    /// Source IP address
    pub source_ip: String,
}

impl TunnelConnection {
    /// Create a new tunnel connection
    pub fn new(tunnel_id: String, ws_sender: WsSender, source_ip: String) -> Self {
        let now = Utc::now();
        Self {
            tunnel_id,
            ws_sender,
            pending_requests: DashMap::new(),
            created_at: now,
            last_activity: RwLock::new(now),
            source_ip,
        }
    }

    /// Send a data message through the tunnel (already encrypted)
    pub async fn send_encrypted(&self, message_type: u8, encrypted: Vec<u8>) -> Result<()> {
        let wire_msg = WireMessage::encode_encrypted(message_type, encrypted);
        self.ws_sender
            .send(WsMessage::Binary(wire_msg))
            .await
            .map_err(|_| anyhow::anyhow!("Failed to send to tunnel"))?;

        // Update last activity
        *self.last_activity.write().await = Utc::now();
        Ok(())
    }

    /// Register a pending request and get a receiver for the response
    pub fn register_request(&self, request_id: String) -> oneshot::Receiver<DataMessage> {
        let (tx, rx) = oneshot::channel();
        tracing::debug!(request_id = %request_id, "Registering regular request");
        self.pending_requests.insert(
            request_id.clone(),
            PendingRequest {
                response_tx: ResponseSender::Single(tx),
                started_at: Utc::now(),
                is_streaming: false,
            },
        );
        tracing::debug!(request_id = %request_id, count = self.pending_requests.len(), "Request registered");
        rx
    }

    /// Register a streaming request (for SSE) and get a receiver for chunks
    pub fn register_streaming_request(
        &self,
        request_id: String,
    ) -> mpsc::Receiver<DataMessage> {
        let (tx, rx) = mpsc::channel(100); // Buffer up to 100 chunks
        self.pending_requests.insert(
            request_id,
            PendingRequest {
                response_tx: ResponseSender::Streaming(tx),
                started_at: Utc::now(),
                is_streaming: true,
            },
        );
        rx
    }

    /// Complete a pending request with a response
    pub fn complete_request(&self, request_id: &str, response: DataMessage) -> bool {
        tracing::debug!(
            request_id = %request_id,
            pending_count = self.pending_requests.len(),
            "Attempting to complete request"
        );
        if let Some((_, pending)) = self.pending_requests.remove(request_id) {
            match pending.response_tx {
                ResponseSender::Single(tx) => {
                    tracing::debug!(request_id = %request_id, "Sending response via oneshot");
                    let _ = tx.send(response);
                }
                ResponseSender::Streaming(tx) => {
                    tracing::debug!(request_id = %request_id, "Sending response via streaming channel");
                    let _ = tx.try_send(response);
                }
            }
            true
        } else {
            tracing::warn!(request_id = %request_id, "Request not found in pending_requests");
            false
        }
    }

    /// Send a chunk to a streaming request (returns false if request not found or not streaming)
    pub async fn send_chunk(&self, request_id: &str, chunk: DataMessage) -> bool {
        if let Some(pending) = self.pending_requests.get(request_id) {
            if let ResponseSender::Streaming(ref tx) = pending.response_tx {
                tracing::debug!(request_id = %request_id, "Sending chunk to streaming request");
                return tx.send(chunk).await.is_ok();
            }
            tracing::warn!(request_id = %request_id, "Found request but it's not streaming");
        }
        false
    }

    /// Complete a streaming request (removes it from pending)
    pub fn complete_streaming_request(&self, request_id: &str) {
        self.pending_requests.remove(request_id);
    }

    /// Cancel all pending requests (called on disconnect)
    pub fn cancel_all_requests(&self) {
        self.pending_requests.clear();
    }
}

/// Alphanumeric characters for tunnel IDs
const ALPHANUMERIC: [char; 62] = [
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
];

/// Generate a unique tunnel ID
pub fn generate_tunnel_id() -> String {
    nanoid::nanoid!(8, &ALPHANUMERIC)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::collections::HashMap;

    // ============================================================================
    // WsMessage Tests
    // ============================================================================

    #[test]
    fn test_ws_message_text() {
        let msg = WsMessage::Text("hello".to_string());
        match msg {
            WsMessage::Text(s) => assert_eq!(s, "hello"),
            _ => panic!("Expected Text message"),
        }
    }

    #[test]
    fn test_ws_message_binary() {
        let data = vec![1, 2, 3, 4, 5];
        let msg = WsMessage::Binary(data.clone());
        match msg {
            WsMessage::Binary(d) => assert_eq!(d, data),
            _ => panic!("Expected Binary message"),
        }
    }

    #[test]
    fn test_ws_message_clone() {
        let text = WsMessage::Text("test".to_string());
        let text_clone = text.clone();
        assert!(matches!(text_clone, WsMessage::Text(s) if s == "test"));

        let binary = WsMessage::Binary(vec![1, 2, 3]);
        let binary_clone = binary.clone();
        assert!(matches!(binary_clone, WsMessage::Binary(d) if d == vec![1, 2, 3]));
    }

    // ============================================================================
    // TunnelConnection Tests
    // ============================================================================

    fn create_test_tunnel() -> (TunnelConnection, mpsc::Receiver<WsMessage>) {
        let (tx, rx) = mpsc::channel(100);
        let tunnel = TunnelConnection::new(
            "test-tunnel-123".to_string(),
            tx,
            "127.0.0.1".to_string(),
        );
        (tunnel, rx)
    }

    #[test]
    fn test_tunnel_connection_creation() {
        let (tunnel, _rx) = create_test_tunnel();

        assert_eq!(tunnel.tunnel_id, "test-tunnel-123");
        assert_eq!(tunnel.source_ip, "127.0.0.1");
        assert!(tunnel.pending_requests.is_empty());
    }

    #[tokio::test]
    async fn test_register_request() {
        let (tunnel, _rx) = create_test_tunnel();

        let _receiver = tunnel.register_request("req-1".to_string());

        assert_eq!(tunnel.pending_requests.len(), 1);
        assert!(tunnel.pending_requests.contains_key("req-1"));

        // Check that it's marked as non-streaming
        let pending = tunnel.pending_requests.get("req-1").unwrap();
        assert!(!pending.is_streaming);
    }

    #[tokio::test]
    async fn test_register_streaming_request() {
        let (tunnel, _rx) = create_test_tunnel();

        let _receiver = tunnel.register_streaming_request("req-sse-1".to_string());

        assert_eq!(tunnel.pending_requests.len(), 1);
        assert!(tunnel.pending_requests.contains_key("req-sse-1"));

        // Check that it's marked as streaming
        let pending = tunnel.pending_requests.get("req-sse-1").unwrap();
        assert!(pending.is_streaming);
    }

    #[tokio::test]
    async fn test_complete_request_success() {
        let (tunnel, _rx) = create_test_tunnel();

        let receiver = tunnel.register_request("req-1".to_string());

        let response = DataMessage::HttpResponse {
            request_id: "req-1".to_string(),
            status: 200,
            headers: HashMap::new(),
            body: None,
            streaming: false,
        };

        let completed = tunnel.complete_request("req-1", response);
        assert!(completed);
        assert!(tunnel.pending_requests.is_empty());

        // The receiver should have the response
        let received = receiver.await.unwrap();
        match received {
            DataMessage::HttpResponse { status, .. } => {
                assert_eq!(status, 200);
            }
            _ => panic!("Expected HttpResponse"),
        }
    }

    #[tokio::test]
    async fn test_complete_request_not_found() {
        let (tunnel, _rx) = create_test_tunnel();

        let response = DataMessage::HttpResponse {
            request_id: "nonexistent".to_string(),
            status: 200,
            headers: HashMap::new(),
            body: None,
            streaming: false,
        };

        let completed = tunnel.complete_request("nonexistent", response);
        assert!(!completed);
    }

    #[tokio::test]
    async fn test_send_chunk_to_streaming_request() {
        let (tunnel, _rx) = create_test_tunnel();

        let mut receiver = tunnel.register_streaming_request("req-sse-1".to_string());

        // Send initial response
        let initial = DataMessage::HttpResponse {
            request_id: "req-sse-1".to_string(),
            status: 200,
            headers: HashMap::new(),
            body: None,
            streaming: true,
        };

        let sent = tunnel.send_chunk("req-sse-1", initial).await;
        assert!(sent);

        // Receive it
        let received = receiver.recv().await.unwrap();
        assert!(matches!(received, DataMessage::HttpResponse { streaming: true, .. }));

        // Send chunk
        let chunk = DataMessage::HttpResponseChunk {
            request_id: "req-sse-1".to_string(),
            chunk: "ZGF0YQ==".to_string(),
            is_final: false,
        };

        let sent = tunnel.send_chunk("req-sse-1", chunk).await;
        assert!(sent);

        // Request should still be pending
        assert!(tunnel.pending_requests.contains_key("req-sse-1"));
    }

    #[tokio::test]
    async fn test_send_chunk_to_nonexistent_request() {
        let (tunnel, _rx) = create_test_tunnel();

        let chunk = DataMessage::HttpResponseChunk {
            request_id: "nonexistent".to_string(),
            chunk: "ZGF0YQ==".to_string(),
            is_final: false,
        };

        let sent = tunnel.send_chunk("nonexistent", chunk).await;
        assert!(!sent);
    }

    #[tokio::test]
    async fn test_send_chunk_to_non_streaming_request() {
        let (tunnel, _rx) = create_test_tunnel();

        // Register a regular (non-streaming) request
        let _receiver = tunnel.register_request("req-regular".to_string());

        let chunk = DataMessage::HttpResponseChunk {
            request_id: "req-regular".to_string(),
            chunk: "ZGF0YQ==".to_string(),
            is_final: false,
        };

        // This should fail because it's not a streaming request
        let sent = tunnel.send_chunk("req-regular", chunk).await;
        assert!(!sent);
    }

    #[tokio::test]
    async fn test_complete_streaming_request() {
        let (tunnel, _rx) = create_test_tunnel();

        let _receiver = tunnel.register_streaming_request("req-sse-1".to_string());
        assert!(tunnel.pending_requests.contains_key("req-sse-1"));

        tunnel.complete_streaming_request("req-sse-1");
        assert!(!tunnel.pending_requests.contains_key("req-sse-1"));
    }

    #[tokio::test]
    async fn test_cancel_all_requests() {
        let (tunnel, _rx) = create_test_tunnel();

        let _r1 = tunnel.register_request("req-1".to_string());
        let _r2 = tunnel.register_request("req-2".to_string());
        let _r3 = tunnel.register_streaming_request("req-sse-1".to_string());

        assert_eq!(tunnel.pending_requests.len(), 3);

        tunnel.cancel_all_requests();

        assert!(tunnel.pending_requests.is_empty());
    }

    #[tokio::test]
    async fn test_multiple_concurrent_requests() {
        let (tunnel, _rx) = create_test_tunnel();

        // Register multiple requests
        let r1 = tunnel.register_request("req-1".to_string());
        let r2 = tunnel.register_request("req-2".to_string());
        let r3 = tunnel.register_streaming_request("req-sse-1".to_string());

        assert_eq!(tunnel.pending_requests.len(), 3);

        // Complete them in different order
        let response2 = DataMessage::HttpResponse {
            request_id: "req-2".to_string(),
            status: 201,
            headers: HashMap::new(),
            body: None,
            streaming: false,
        };
        tunnel.complete_request("req-2", response2);
        assert_eq!(tunnel.pending_requests.len(), 2);

        let response1 = DataMessage::HttpResponse {
            request_id: "req-1".to_string(),
            status: 200,
            headers: HashMap::new(),
            body: None,
            streaming: false,
        };
        tunnel.complete_request("req-1", response1);
        assert_eq!(tunnel.pending_requests.len(), 1);

        // Verify responses
        let received1 = r1.await.unwrap();
        assert!(matches!(received1, DataMessage::HttpResponse { status: 200, .. }));

        let received2 = r2.await.unwrap();
        assert!(matches!(received2, DataMessage::HttpResponse { status: 201, .. }));

        // Complete streaming request
        tunnel.complete_streaming_request("req-sse-1");
        assert!(tunnel.pending_requests.is_empty());
        drop(r3);
    }

    #[tokio::test]
    async fn test_send_encrypted() {
        let (tunnel, mut rx) = create_test_tunnel();

        let encrypted = vec![0xAB, 0xCD, 0xEF];
        let result = tunnel.send_encrypted(0x01, encrypted.clone()).await;
        assert!(result.is_ok());

        // Check that the message was sent
        let msg = rx.recv().await.unwrap();
        match msg {
            WsMessage::Binary(data) => {
                assert_eq!(data[0], 0x01); // Message type
                assert_eq!(&data[1..], &encrypted[..]);
            }
            _ => panic!("Expected Binary message"),
        }
    }

    // ============================================================================
    // Tunnel ID Generation Tests
    // ============================================================================

    #[test]
    fn test_generate_tunnel_id_length() {
        let id = generate_tunnel_id();
        assert_eq!(id.len(), 8);
    }

    #[test]
    fn test_generate_tunnel_id_alphanumeric() {
        let id = generate_tunnel_id();
        assert!(id.chars().all(|c| c.is_ascii_alphanumeric()));
    }

    #[test]
    fn test_generate_tunnel_id_uniqueness() {
        let ids: std::collections::HashSet<String> = (0..100)
            .map(|_| generate_tunnel_id())
            .collect();

        // All 100 IDs should be unique
        assert_eq!(ids.len(), 100);
    }

    // ============================================================================
    // Timestamp Tests
    // ============================================================================

    #[tokio::test]
    async fn test_tunnel_timestamps() {
        let (tunnel, _rx) = create_test_tunnel();

        let created = tunnel.created_at;
        let initial_activity = *tunnel.last_activity.read().await;

        // Timestamps should be approximately equal at creation
        assert!((created - initial_activity).num_milliseconds().abs() < 100);

        // Sleep briefly to ensure time passes
        tokio::time::sleep(tokio::time::Duration::from_millis(10)).await;

        // Send a message to update last_activity
        let _ = tunnel.send_encrypted(0x01, vec![1, 2, 3]).await;

        let updated_activity = *tunnel.last_activity.read().await;
        assert!(updated_activity > initial_activity);
    }

    // ============================================================================
    // Edge Cases
    // ============================================================================

    #[tokio::test]
    async fn test_complete_same_request_twice() {
        let (tunnel, _rx) = create_test_tunnel();

        let receiver = tunnel.register_request("req-1".to_string());

        let response = DataMessage::HttpResponse {
            request_id: "req-1".to_string(),
            status: 200,
            headers: HashMap::new(),
            body: None,
            streaming: false,
        };

        // First completion should succeed
        let first = tunnel.complete_request("req-1", response.clone());
        assert!(first);

        // Second completion should fail (request already removed)
        let second = tunnel.complete_request("req-1", response);
        assert!(!second);

        drop(receiver);
    }

    #[tokio::test]
    async fn test_request_with_empty_id() {
        let (tunnel, _rx) = create_test_tunnel();

        let _receiver = tunnel.register_request("".to_string());
        assert!(tunnel.pending_requests.contains_key(""));

        let response = DataMessage::HttpResponse {
            request_id: "".to_string(),
            status: 200,
            headers: HashMap::new(),
            body: None,
            streaming: false,
        };

        let completed = tunnel.complete_request("", response);
        assert!(completed);
    }
}