/// Integration test: starts a mock gRPC server and connects the client.
/// Tests the full bidirectional stream lifecycle without needing Sol or Mistral.

use std::pin::Pin;
use std::sync::Arc;

use futures::Stream;
use sunbeam_proto::sunbeam_code_v1::code_agent_server::{CodeAgent, CodeAgentServer};
use sunbeam_proto::sunbeam_code_v1::*;
use tokio::sync::mpsc;
use tokio_stream::wrappers::ReceiverStream;
use tonic::{Request, Response, Status, Streaming};

/// Mock server that echoes back user input as assistant text.
struct MockCodeAgent;

#[tonic::async_trait]
impl CodeAgent for MockCodeAgent {
    type SessionStream = Pin<Box<dyn Stream<Item = Result<ServerMessage, Status>> + Send>>;

    async fn session(
        &self,
        request: Request<Streaming<ClientMessage>>,
    ) -> Result<Response<Self::SessionStream>, Status> {
        let mut in_stream = request.into_inner();
        let (tx, rx) = mpsc::channel(32);

        tokio::spawn(async move {
            // Wait for StartSession
            if let Ok(Some(msg)) = in_stream.message().await {
                if let Some(client_message::Payload::Start(start)) = msg.payload {
                    let _ = tx.send(Ok(ServerMessage {
                        payload: Some(server_message::Payload::Ready(SessionReady {
                            session_id: "test-session-123".into(),
                            room_id: "!test-room:local".into(),
                            model: if start.model.is_empty() {
                                "devstral-2".into()
                            } else {
                                start.model
                            },
                        })),
                    })).await;
                }
            }

            // Echo loop
            while let Ok(Some(msg)) = in_stream.message().await {
                match msg.payload {
                    Some(client_message::Payload::Input(input)) => {
                        let _ = tx.send(Ok(ServerMessage {
                            payload: Some(server_message::Payload::Done(TextDone {
                                full_text: format!("[echo] {}", input.text),
                                input_tokens: 10,
                                output_tokens: 5,
                            })),
                        })).await;
                    }
                    Some(client_message::Payload::End(_)) => {
                        let _ = tx.send(Ok(ServerMessage {
                            payload: Some(server_message::Payload::End(SessionEnd {
                                summary: "Session ended.".into(),
                            })),
                        })).await;
                        break;
                    }
                    _ => {}
                }
            }
        });

        Ok(Response::new(Box::pin(ReceiverStream::new(rx))))
    }
}

#[tokio::test]
async fn test_session_lifecycle() {
    // Start mock server on a random port
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
    let addr = listener.local_addr().unwrap();

    tokio::spawn(async move {
        let incoming = tokio_stream::wrappers::TcpListenerStream::new(listener);
        tonic::transport::Server::builder()
            .add_service(CodeAgentServer::new(MockCodeAgent))
            .serve_with_incoming(incoming)
            .await
            .unwrap();
    });

    // Give server a moment to start
    tokio::time::sleep(std::time::Duration::from_millis(100)).await;

    // Connect client
    let endpoint = format!("http://{addr}");

    use sunbeam_proto::sunbeam_code_v1::code_agent_client::CodeAgentClient;
    let mut client = CodeAgentClient::connect(endpoint).await.unwrap();

    let (tx, client_rx) = mpsc::channel::<ClientMessage>(32);
    let client_stream = ReceiverStream::new(client_rx);
    let response = client.session(client_stream).await.unwrap();
    let mut rx = response.into_inner();

    // Send StartSession
    tx.send(ClientMessage {
        payload: Some(client_message::Payload::Start(StartSession {
            project_path: "/test/project".into(),
            prompt_md: "test prompt".into(),
            config_toml: String::new(),
            git_branch: "main".into(),
            git_status: String::new(),
            file_tree: vec!["src/".into(), "Cargo.toml".into()],
            model: "test-model".into(),
            client_tools: vec![],
        })),
    }).await.unwrap();

    // Receive SessionReady
    let msg = rx.message().await.unwrap().unwrap();
    match msg.payload {
        Some(server_message::Payload::Ready(ready)) => {
            assert_eq!(ready.session_id, "test-session-123");
            assert_eq!(ready.model, "test-model");
        }
        other => panic!("Expected SessionReady, got {other:?}"),
    }

    // Send a chat message
    tx.send(ClientMessage {
        payload: Some(client_message::Payload::Input(UserInput {
            text: "hello sol".into(),
        })),
    }).await.unwrap();

    // Receive echo response
    let msg = rx.message().await.unwrap().unwrap();
    match msg.payload {
        Some(server_message::Payload::Done(done)) => {
            assert_eq!(done.full_text, "[echo] hello sol");
            assert_eq!(done.input_tokens, 10);
            assert_eq!(done.output_tokens, 5);
        }
        other => panic!("Expected TextDone, got {other:?}"),
    }

    // End session
    tx.send(ClientMessage {
        payload: Some(client_message::Payload::End(EndSession {})),
    }).await.unwrap();

    let msg = rx.message().await.unwrap().unwrap();
    match msg.payload {
        Some(server_message::Payload::End(end)) => {
            assert_eq!(end.summary, "Session ended.");
        }
        other => panic!("Expected SessionEnd, got {other:?}"),
    }
}

#[tokio::test]
async fn test_multiple_messages() {
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
    let addr = listener.local_addr().unwrap();

    tokio::spawn(async move {
        let incoming = tokio_stream::wrappers::TcpListenerStream::new(listener);
        tonic::transport::Server::builder()
            .add_service(CodeAgentServer::new(MockCodeAgent))
            .serve_with_incoming(incoming)
            .await
            .unwrap();
    });

    tokio::time::sleep(std::time::Duration::from_millis(100)).await;

    let endpoint = format!("http://{addr}");
    use sunbeam_proto::sunbeam_code_v1::code_agent_client::CodeAgentClient;
    let mut client = CodeAgentClient::connect(endpoint).await.unwrap();

    let (tx, client_rx) = mpsc::channel::<ClientMessage>(32);
    let client_stream = ReceiverStream::new(client_rx);
    let response = client.session(client_stream).await.unwrap();
    let mut rx = response.into_inner();

    // Start
    tx.send(ClientMessage {
        payload: Some(client_message::Payload::Start(StartSession {
            project_path: "/test".into(),
            model: "devstral-2".into(),
            ..Default::default()
        })),
    }).await.unwrap();

    let _ = rx.message().await.unwrap().unwrap(); // SessionReady

    // Send 3 messages and verify each echo
    for i in 0..3 {
        tx.send(ClientMessage {
            payload: Some(client_message::Payload::Input(UserInput {
                text: format!("message {i}"),
            })),
        }).await.unwrap();

        let msg = rx.message().await.unwrap().unwrap();
        match msg.payload {
            Some(server_message::Payload::Done(done)) => {
                assert_eq!(done.full_text, format!("[echo] message {i}"));
            }
            other => panic!("Expected TextDone for message {i}, got {other:?}"),
        }
    }
}