use crate::http::context::{AppContext, PermissionDecision};
use crate::http::workflow::{PipelineState, load_pipeline_state};
use crate::io::onboarding;
use crate::io::watcher::WatcherEvent;
use crate::llm::chat;
use crate::llm::types::Message;
use futures::{SinkExt, StreamExt};
use poem::handler;
use poem::web::Data;
use poem::web::websocket::{Message as WsMessage, WebSocket};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::{mpsc, oneshot};

#[derive(Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
/// WebSocket request messages sent by the client.
///
/// - `chat` starts a streaming chat session.
/// - `cancel` stops the active session.
/// - `permission_response` approves or denies a pending permission request.
enum WsRequest {
    Chat {
        messages: Vec<Message>,
        config: chat::ProviderConfig,
    },
    Cancel,
    PermissionResponse {
        request_id: String,
        approved: bool,
        #[serde(default)]
        always_allow: bool,
    },
    /// Heartbeat ping from the client. The server responds with `Pong` so the
    /// client can detect stale (half-closed) connections.
    Ping,
    /// A quick side question answered from current conversation context.
    /// The question and response are NOT added to the conversation history
    /// and no tool calls are made.
    SideQuestion {
        question: String,
        context_messages: Vec<Message>,
        config: chat::ProviderConfig,
    },
}

#[derive(Serialize)]
#[serde(tag = "type", rename_all = "snake_case")]
/// WebSocket response messages sent by the server.
///
/// - `token` streams partial model output.
/// - `update` pushes the updated message history.
/// - `error` reports a request or processing failure.
/// - `work_item_changed` notifies that a `.story_kit/work/` file changed.
/// - `agent_config_changed` notifies that `.story_kit/project.toml` was modified.
enum WsResponse {
    Token {
        content: String,
    },
    Update {
        messages: Vec<Message>,
    },
    /// Session ID for Claude Code conversation resumption.
    SessionId {
        session_id: String,
    },
    Error {
        message: String,
    },
    /// Filesystem watcher notification: a work-pipeline file was created or
    /// modified and auto-committed. The frontend can use this to refresh its
    /// story/bug list without polling.
    WorkItemChanged {
        stage: String,
        item_id: String,
        action: String,
        commit_msg: String,
    },
    /// Full pipeline state pushed on connect and after every work-item watcher event.
    PipelineState {
        backlog: Vec<crate::http::workflow::UpcomingStory>,
        current: Vec<crate::http::workflow::UpcomingStory>,
        qa: Vec<crate::http::workflow::UpcomingStory>,
        merge: Vec<crate::http::workflow::UpcomingStory>,
        done: Vec<crate::http::workflow::UpcomingStory>,
    },
    /// `.story_kit/project.toml` was modified; the frontend should re-fetch the
    /// agent roster. Does NOT trigger a pipeline state refresh.
    AgentConfigChanged,
    /// An agent's state changed (started, stopped, completed, etc.).
    /// Triggers a pipeline state refresh and tells the frontend to re-fetch
    /// the agent list.
    AgentStateChanged,
    /// Claude Code is requesting user approval before executing a tool.
    PermissionRequest {
        request_id: String,
        tool_name: String,
        tool_input: serde_json::Value,
    },
    /// The agent started assembling a tool call; shows live status in the UI.
    ToolActivity {
        tool_name: String,
    },
    /// Real-time progress from the server startup reconciliation pass.
    /// `status` is one of: "checking", "gates_running", "advanced", "skipped",
    /// "failed", "done". `story_id` is empty for the overall "done" event.
    ReconciliationProgress {
        story_id: String,
        status: String,
        message: String,
    },
    /// Heartbeat response to a client `Ping`. Lets the client confirm the
    /// connection is alive and cancel any stale-connection timeout.
    Pong,
    /// Streaming thinking token from an extended-thinking block.
    /// Sent separately from `Token` so the frontend can render them in
    /// a constrained, scrollable ThinkingBlock rather than inline.
    ThinkingToken {
        content: String,
    },
    /// Sent on connect when the project's spec files still contain scaffold
    /// placeholder content and the user needs to go through onboarding.
    OnboardingStatus {
        needs_onboarding: bool,
    },
    /// Streaming token from a `/btw` side question response.
    SideQuestionToken {
        content: String,
    },
    /// Final signal that the `/btw` side question has been fully answered.
    SideQuestionDone {
        response: String,
    },
}

impl From<WatcherEvent> for Option<WsResponse> {
    fn from(e: WatcherEvent) -> Self {
        match e {
            WatcherEvent::WorkItem {
                stage,
                item_id,
                action,
                commit_msg,
            } => Some(WsResponse::WorkItemChanged {
                stage,
                item_id,
                action,
                commit_msg,
            }),
            WatcherEvent::ConfigChanged => Some(WsResponse::AgentConfigChanged),
            WatcherEvent::AgentStateChanged => Some(WsResponse::AgentStateChanged),
            // MergeFailure is handled by the Matrix notification listener only;
            // no WebSocket message is needed for the frontend.
            WatcherEvent::MergeFailure { .. } => None,
        }
    }
}

impl From<PipelineState> for WsResponse {
    fn from(s: PipelineState) -> Self {
        WsResponse::PipelineState {
            backlog: s.backlog,
            current: s.current,
            qa: s.qa,
            merge: s.merge,
            done: s.done,
        }
    }
}

#[handler]
/// WebSocket endpoint for streaming chat responses, cancellation, and
/// filesystem watcher notifications.
///
/// Accepts JSON `WsRequest` messages and streams `WsResponse` messages.
pub async fn ws_handler(ws: WebSocket, ctx: Data<&Arc<AppContext>>) -> impl poem::IntoResponse {
    let ctx = ctx.0.clone();
    ws.on_upgrade(move |socket| async move {
        let (mut sink, mut stream) = socket.split();
        let (tx, mut rx) = mpsc::unbounded_channel::<WsResponse>();

        let forward = tokio::spawn(async move {
            while let Some(msg) = rx.recv().await {
                if let Ok(text) = serde_json::to_string(&msg)
                    && sink.send(WsMessage::Text(text)).await.is_err()
                {
                    break;
                }
            }
        });

        // Push initial pipeline state to the client on connect.
        if let Ok(state) = load_pipeline_state(ctx.as_ref()) {
            let _ = tx.send(state.into());
        }

        // Push onboarding status so the frontend knows whether to show
        // the onboarding welcome flow.
        {
            let needs = ctx
                .state
                .get_project_root()
                .map(|root| onboarding::check_onboarding_status(&root).needs_onboarding())
                .unwrap_or(false);
            let _ = tx.send(WsResponse::OnboardingStatus {
                needs_onboarding: needs,
            });
        }

        // Subscribe to filesystem watcher events and forward them to the client.
        // After each work-item event, also push the updated pipeline state.
        // Config-changed events are forwarded as-is without a pipeline refresh.
        let tx_watcher = tx.clone();
        let ctx_watcher = ctx.clone();
        let mut watcher_rx = ctx.watcher_tx.subscribe();
        tokio::spawn(async move {
            loop {
                match watcher_rx.recv().await {
                    Ok(evt) => {
                        let needs_pipeline_refresh = matches!(
                            evt,
                            crate::io::watcher::WatcherEvent::WorkItem { .. }
                                | crate::io::watcher::WatcherEvent::AgentStateChanged
                        );
                        let ws_msg: Option<WsResponse> = evt.into();
                        if let Some(msg) = ws_msg && tx_watcher.send(msg).is_err() {
                            break;
                        }
                        // Push refreshed pipeline state after work-item changes and
                        // agent state changes (so the board updates agent lozenges).
                        if needs_pipeline_refresh
                            && let Ok(state) = load_pipeline_state(ctx_watcher.as_ref())
                            && tx_watcher.send(state.into()).is_err()
                        {
                            break;
                        }
                    }
                    // Lagged: skip missed events, keep going.
                    Err(tokio::sync::broadcast::error::RecvError::Lagged(_)) => continue,
                    Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
                }
            }
        });

        // Subscribe to startup reconciliation events and forward them to the client.
        let tx_reconcile = tx.clone();
        let mut reconcile_rx = ctx.reconciliation_tx.subscribe();
        tokio::spawn(async move {
            loop {
                match reconcile_rx.recv().await {
                    Ok(evt) => {
                        if tx_reconcile
                            .send(WsResponse::ReconciliationProgress {
                                story_id: evt.story_id,
                                status: evt.status,
                                message: evt.message,
                            })
                            .is_err()
                        {
                            break;
                        }
                    }
                    Err(tokio::sync::broadcast::error::RecvError::Lagged(_)) => continue,
                    Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
                }
            }
        });

        // Map of pending permission request_id → oneshot responder.
        // Permission requests arrive from the MCP `prompt_permission` tool via
        // `ctx.perm_rx` and are forwarded to the client as `PermissionRequest`.
        // When the client responds, we resolve the corresponding oneshot.
        let mut pending_perms: HashMap<String, oneshot::Sender<PermissionDecision>> = HashMap::new();

        loop {
            // Outer loop: wait for the next WebSocket message.
            let Some(Ok(WsMessage::Text(text))) = stream.next().await else {
                break;
            };

            let parsed: Result<WsRequest, _> = serde_json::from_str(&text);
            match parsed {
                Ok(WsRequest::Chat { messages, config }) => {
                    let tx_updates = tx.clone();
                    let tx_tokens = tx.clone();
                    let tx_thinking = tx.clone();
                    let tx_activity = tx.clone();
                    let ctx_clone = ctx.clone();

                    // Build the chat future without driving it yet so we can
                    // interleave it with permission-request forwarding.
                    let chat_fut = chat::chat(
                        messages,
                        config,
                        &ctx_clone.state,
                        ctx_clone.store.as_ref(),
                        move |history| {
                            let _ = tx_updates.send(WsResponse::Update {
                                messages: history.to_vec(),
                            });
                        },
                        move |token| {
                            let _ = tx_tokens.send(WsResponse::Token {
                                content: token.to_string(),
                            });
                        },
                        move |thinking: &str| {
                            let _ = tx_thinking.send(WsResponse::ThinkingToken {
                                content: thinking.to_string(),
                            });
                        },
                        move |tool_name: &str| {
                            let _ = tx_activity.send(WsResponse::ToolActivity {
                                tool_name: tool_name.to_string(),
                            });
                        },
                    );
                    tokio::pin!(chat_fut);

                    // Lock the permission receiver for the duration of this chat
                    // session. Permission requests from the MCP tool arrive here.
                    let mut perm_rx = ctx.perm_rx.lock().await;

                    // Inner loop: drive the chat while concurrently handling
                    // permission requests (from MCP) and WebSocket messages.
                    let chat_result = loop {
                        tokio::select! {
                            result = &mut chat_fut => break result,

                            // Forward permission requests from MCP tool to the client.
                            Some(perm_fwd) = perm_rx.recv() => {
                                let _ = tx.send(WsResponse::PermissionRequest {
                                    request_id: perm_fwd.request_id.clone(),
                                    tool_name: perm_fwd.tool_name.clone(),
                                    tool_input: perm_fwd.tool_input.clone(),
                                });
                                pending_perms.insert(
                                    perm_fwd.request_id,
                                    perm_fwd.response_tx,
                                );
                            }

                            // Handle WebSocket messages during an active chat
                            // (permission responses and cancellations).
                            Some(Ok(WsMessage::Text(inner_text))) = stream.next() => {
                                match serde_json::from_str::<WsRequest>(&inner_text) {
                                    Ok(WsRequest::PermissionResponse { request_id, approved, always_allow }) => {
                                        if let Some(resp_tx) = pending_perms.remove(&request_id) {
                                            let decision = if always_allow {
                                                PermissionDecision::AlwaysAllow
                                            } else if approved {
                                                PermissionDecision::Approve
                                            } else {
                                                PermissionDecision::Deny
                                            };
                                            let _ = resp_tx.send(decision);
                                        }
                                    }
                                    Ok(WsRequest::Cancel) => {
                                        let _ = chat::cancel_chat(&ctx.state);
                                    }
                                    Ok(WsRequest::Ping) => {
                                        let _ = tx.send(WsResponse::Pong);
                                    }
                                    Ok(WsRequest::SideQuestion { question, context_messages, config }) => {
                                        let tx_side = tx.clone();
                                        let store = ctx.store.clone();
                                        tokio::spawn(async move {
                                            let result = chat::side_question(
                                                context_messages,
                                                question,
                                                config,
                                                store.as_ref(),
                                                |token| {
                                                    let _ = tx_side.send(WsResponse::SideQuestionToken {
                                                        content: token.to_string(),
                                                    });
                                                },
                                            ).await;
                                            match result {
                                                Ok(response) => {
                                                    let _ = tx_side.send(WsResponse::SideQuestionDone { response });
                                                }
                                                Err(err) => {
                                                    let _ = tx_side.send(WsResponse::SideQuestionDone {
                                                        response: format!("Error: {err}"),
                                                    });
                                                }
                                            }
                                        });
                                    }
                                    _ => {}
                                }
                            }
                        }
                    };

                    match chat_result {
                        Ok(chat_result) => {
                            if let Some(sid) = chat_result.session_id {
                                let _ = tx.send(WsResponse::SessionId { session_id: sid });
                            }
                        }
                        Err(err) => {
                            let _ = tx.send(WsResponse::Error { message: err });
                        }
                    }
                }
                Ok(WsRequest::Cancel) => {
                    let _ = chat::cancel_chat(&ctx.state);
                }
                Ok(WsRequest::Ping) => {
                    let _ = tx.send(WsResponse::Pong);
                }
                Ok(WsRequest::PermissionResponse { .. }) => {
                    // Permission responses outside an active chat are ignored.
                }
                Ok(WsRequest::SideQuestion {
                    question,
                    context_messages,
                    config,
                }) => {
                    let tx_side = tx.clone();
                    let store = ctx.store.clone();
                    tokio::spawn(async move {
                        let result = chat::side_question(
                            context_messages,
                            question,
                            config,
                            store.as_ref(),
                            |token| {
                                let _ = tx_side.send(WsResponse::SideQuestionToken {
                                    content: token.to_string(),
                                });
                            },
                        )
                        .await;
                        match result {
                            Ok(response) => {
                                let _ = tx_side
                                    .send(WsResponse::SideQuestionDone { response });
                            }
                            Err(err) => {
                                let _ = tx_side.send(WsResponse::SideQuestionDone {
                                    response: format!("Error: {err}"),
                                });
                            }
                        }
                    });
                }
                Err(err) => {
                    let _ = tx.send(WsResponse::Error {
                        message: format!("Invalid request: {err}"),
                    });
                }
            }
        }

        drop(tx);
        let _ = forward.await;
    })
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::http::workflow::{PipelineState, UpcomingStory};
    use crate::io::watcher::WatcherEvent;

    // ── WsRequest deserialization ────────────────────────────────────

    #[test]
    fn deserialize_chat_request() {
        let json = r#"{
            "type": "chat",
            "messages": [
                {"role": "user", "content": "hello"}
            ],
            "config": {
                "provider": "ollama",
                "model": "llama3"
            }
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::Chat { messages, config } => {
                assert_eq!(messages.len(), 1);
                assert_eq!(messages[0].content, "hello");
                assert_eq!(config.provider, "ollama");
                assert_eq!(config.model, "llama3");
            }
            _ => panic!("expected Chat variant"),
        }
    }

    #[test]
    fn deserialize_chat_request_with_optional_fields() {
        let json = r#"{
            "type": "chat",
            "messages": [],
            "config": {
                "provider": "anthropic",
                "model": "claude-3-5-sonnet",
                "base_url": "https://api.anthropic.com",
                "enable_tools": true,
                "session_id": "sess-123"
            }
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::Chat { messages, config } => {
                assert!(messages.is_empty());
                assert_eq!(config.base_url.as_deref(), Some("https://api.anthropic.com"));
                assert_eq!(config.enable_tools, Some(true));
                assert_eq!(config.session_id.as_deref(), Some("sess-123"));
            }
            _ => panic!("expected Chat variant"),
        }
    }

    #[test]
    fn deserialize_cancel_request() {
        let json = r#"{"type": "cancel"}"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        assert!(matches!(req, WsRequest::Cancel));
    }

    #[test]
    fn deserialize_ping_request() {
        let json = r#"{"type": "ping"}"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        assert!(matches!(req, WsRequest::Ping));
    }

    #[test]
    fn deserialize_permission_response_approved() {
        let json = r#"{
            "type": "permission_response",
            "request_id": "req-42",
            "approved": true
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::PermissionResponse {
                request_id,
                approved,
                always_allow,
            } => {
                assert_eq!(request_id, "req-42");
                assert!(approved);
                assert!(!always_allow);
            }
            _ => panic!("expected PermissionResponse variant"),
        }
    }

    #[test]
    fn deserialize_permission_response_denied() {
        let json = r#"{
            "type": "permission_response",
            "request_id": "req-99",
            "approved": false
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::PermissionResponse {
                request_id,
                approved,
                always_allow,
            } => {
                assert_eq!(request_id, "req-99");
                assert!(!approved);
                assert!(!always_allow);
            }
            _ => panic!("expected PermissionResponse variant"),
        }
    }

    #[test]
    fn deserialize_permission_response_always_allow() {
        let json = r#"{
            "type": "permission_response",
            "request_id": "req-100",
            "approved": true,
            "always_allow": true
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::PermissionResponse {
                request_id,
                approved,
                always_allow,
            } => {
                assert_eq!(request_id, "req-100");
                assert!(approved);
                assert!(always_allow);
            }
            _ => panic!("expected PermissionResponse variant"),
        }
    }

    #[test]
    fn deserialize_unknown_type_fails() {
        let json = r#"{"type": "unknown_type"}"#;
        let result: Result<WsRequest, _> = serde_json::from_str(json);
        assert!(result.is_err());
    }

    #[test]
    fn deserialize_invalid_json_fails() {
        let result: Result<WsRequest, _> = serde_json::from_str("not json");
        assert!(result.is_err());
    }

    #[test]
    fn deserialize_missing_type_tag_fails() {
        let json = r#"{"messages": [], "config": {"provider": "x", "model": "y"}}"#;
        let result: Result<WsRequest, _> = serde_json::from_str(json);
        assert!(result.is_err());
    }

    // ── WsResponse serialization ────────────────────────────────────

    #[test]
    fn serialize_token_response() {
        let resp = WsResponse::Token {
            content: "hello world".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "token");
        assert_eq!(json["content"], "hello world");
    }

    #[test]
    fn serialize_update_response() {
        let msg = Message {
            role: crate::llm::types::Role::Assistant,
            content: "response".to_string(),
            tool_calls: None,
            tool_call_id: None,
        };
        let resp = WsResponse::Update {
            messages: vec![msg],
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "update");
        assert_eq!(json["messages"].as_array().unwrap().len(), 1);
        assert_eq!(json["messages"][0]["content"], "response");
    }

    #[test]
    fn serialize_session_id_response() {
        let resp = WsResponse::SessionId {
            session_id: "sess-abc".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "session_id");
        assert_eq!(json["session_id"], "sess-abc");
    }

    #[test]
    fn serialize_error_response() {
        let resp = WsResponse::Error {
            message: "something broke".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "error");
        assert_eq!(json["message"], "something broke");
    }

    #[test]
    fn serialize_work_item_changed_response() {
        let resp = WsResponse::WorkItemChanged {
            stage: "2_current".to_string(),
            item_id: "42_story_foo".to_string(),
            action: "start".to_string(),
            commit_msg: "story-kit: start 42_story_foo".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "work_item_changed");
        assert_eq!(json["stage"], "2_current");
        assert_eq!(json["item_id"], "42_story_foo");
        assert_eq!(json["action"], "start");
        assert_eq!(json["commit_msg"], "story-kit: start 42_story_foo");
    }

    #[test]
    fn serialize_pipeline_state_response() {
        let story = crate::http::workflow::UpcomingStory {
            story_id: "10_story_test".to_string(),
            name: Some("Test".to_string()),
            error: None,
            merge_failure: None,
            agent: None,
            review_hold: None,
            manual_qa: None,
        };
        let resp = WsResponse::PipelineState {
            backlog: vec![story],
            current: vec![],
            qa: vec![],
            merge: vec![],
            done: vec![],
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "pipeline_state");
        assert_eq!(json["backlog"].as_array().unwrap().len(), 1);
        assert_eq!(json["backlog"][0]["story_id"], "10_story_test");
        assert!(json["current"].as_array().unwrap().is_empty());
        assert!(json["done"].as_array().unwrap().is_empty());
    }

    #[test]
    fn serialize_agent_config_changed_response() {
        let resp = WsResponse::AgentConfigChanged;
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "agent_config_changed");
    }

    #[test]
    fn serialize_pong_response() {
        let resp = WsResponse::Pong;
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "pong");
    }

    #[test]
    fn serialize_thinking_token_response() {
        let resp = WsResponse::ThinkingToken {
            content: "I need to think about this...".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "thinking_token");
        assert_eq!(json["content"], "I need to think about this...");
    }

    #[test]
    fn serialize_onboarding_status_true() {
        let resp = WsResponse::OnboardingStatus {
            needs_onboarding: true,
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "onboarding_status");
        assert_eq!(json["needs_onboarding"], true);
    }

    #[test]
    fn serialize_onboarding_status_false() {
        let resp = WsResponse::OnboardingStatus {
            needs_onboarding: false,
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "onboarding_status");
        assert_eq!(json["needs_onboarding"], false);
    }

    #[test]
    fn serialize_permission_request_response() {
        let resp = WsResponse::PermissionRequest {
            request_id: "perm-1".to_string(),
            tool_name: "Bash".to_string(),
            tool_input: serde_json::json!({"command": "ls"}),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "permission_request");
        assert_eq!(json["request_id"], "perm-1");
        assert_eq!(json["tool_name"], "Bash");
        assert_eq!(json["tool_input"]["command"], "ls");
    }

    #[test]
    fn serialize_tool_activity_response() {
        let resp = WsResponse::ToolActivity {
            tool_name: "Read".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "tool_activity");
        assert_eq!(json["tool_name"], "Read");
    }

    #[test]
    fn serialize_reconciliation_progress_response() {
        let resp = WsResponse::ReconciliationProgress {
            story_id: "50_story_x".to_string(),
            status: "gates_running".to_string(),
            message: "Running clippy...".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "reconciliation_progress");
        assert_eq!(json["story_id"], "50_story_x");
        assert_eq!(json["status"], "gates_running");
        assert_eq!(json["message"], "Running clippy...");
    }

    // ── From<WatcherEvent> for Option<WsResponse> ───────────────────

    #[test]
    fn watcher_work_item_converts_to_ws_response() {
        let evt = WatcherEvent::WorkItem {
            stage: "2_current".to_string(),
            item_id: "42_story_foo".to_string(),
            action: "start".to_string(),
            commit_msg: "story-kit: start 42_story_foo".to_string(),
        };
        let ws_msg: Option<WsResponse> = evt.into();
        let ws_msg = ws_msg.expect("WorkItem should produce Some");
        let json = serde_json::to_value(&ws_msg).unwrap();
        assert_eq!(json["type"], "work_item_changed");
        assert_eq!(json["stage"], "2_current");
        assert_eq!(json["item_id"], "42_story_foo");
        assert_eq!(json["action"], "start");
    }

    #[test]
    fn watcher_config_changed_converts_to_ws_response() {
        let evt = WatcherEvent::ConfigChanged;
        let ws_msg: Option<WsResponse> = evt.into();
        let ws_msg = ws_msg.expect("ConfigChanged should produce Some");
        let json = serde_json::to_value(&ws_msg).unwrap();
        assert_eq!(json["type"], "agent_config_changed");
    }

    // ── From<PipelineState> for WsResponse ──────────────────────────

    #[test]
    fn pipeline_state_converts_to_ws_response() {
        let state = PipelineState {
            backlog: vec![UpcomingStory {
                story_id: "1_story_a".to_string(),
                name: Some("Story A".to_string()),
                error: None,
                merge_failure: None,
                agent: None,
                review_hold: None,
                manual_qa: None,
            }],
            current: vec![UpcomingStory {
                story_id: "2_story_b".to_string(),
                name: Some("Story B".to_string()),
                error: None,
                merge_failure: None,
                agent: None,
                review_hold: None,
                manual_qa: None,
            }],
            qa: vec![],
            merge: vec![],
            done: vec![UpcomingStory {
                story_id: "50_story_done".to_string(),
                name: Some("Done Story".to_string()),
                error: None,
                merge_failure: None,
                agent: None,
                review_hold: None,
                manual_qa: None,
            }],
        };
        let resp: WsResponse = state.into();
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "pipeline_state");
        assert_eq!(json["backlog"].as_array().unwrap().len(), 1);
        assert_eq!(json["backlog"][0]["story_id"], "1_story_a");
        assert_eq!(json["current"].as_array().unwrap().len(), 1);
        assert_eq!(json["current"][0]["story_id"], "2_story_b");
        assert!(json["qa"].as_array().unwrap().is_empty());
        assert!(json["merge"].as_array().unwrap().is_empty());
        assert_eq!(json["done"].as_array().unwrap().len(), 1);
        assert_eq!(json["done"][0]["story_id"], "50_story_done");
    }

    #[test]
    fn empty_pipeline_state_converts_to_ws_response() {
        let state = PipelineState {
            backlog: vec![],
            current: vec![],
            qa: vec![],
            merge: vec![],
            done: vec![],
        };
        let resp: WsResponse = state.into();
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "pipeline_state");
        assert!(json["backlog"].as_array().unwrap().is_empty());
        assert!(json["current"].as_array().unwrap().is_empty());
        assert!(json["qa"].as_array().unwrap().is_empty());
        assert!(json["merge"].as_array().unwrap().is_empty());
        assert!(json["done"].as_array().unwrap().is_empty());
    }

    // ── WsResponse JSON round-trip (string form) ────────────────────

    #[test]
    fn ws_response_serializes_to_parseable_json_string() {
        let resp = WsResponse::Error {
            message: "test error".to_string(),
        };
        let text = serde_json::to_string(&resp).unwrap();
        let parsed: serde_json::Value = serde_json::from_str(&text).unwrap();
        assert_eq!(parsed["type"], "error");
        assert_eq!(parsed["message"], "test error");
    }

    #[test]
    fn ws_response_update_with_empty_messages() {
        let resp = WsResponse::Update { messages: vec![] };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "update");
        assert!(json["messages"].as_array().unwrap().is_empty());
    }

    #[test]
    fn ws_response_token_with_empty_content() {
        let resp = WsResponse::Token {
            content: String::new(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["type"], "token");
        assert_eq!(json["content"], "");
    }

    #[test]
    fn ws_response_error_with_special_characters() {
        let resp = WsResponse::Error {
            message: "error: \"quoted\" & <tagged>".to_string(),
        };
        let text = serde_json::to_string(&resp).unwrap();
        let parsed: serde_json::Value = serde_json::from_str(&text).unwrap();
        assert_eq!(parsed["message"], "error: \"quoted\" & <tagged>");
    }

    // ── WsRequest edge cases ────────────────────────────────────────

    #[test]
    fn deserialize_chat_with_multiple_messages() {
        let json = r#"{
            "type": "chat",
            "messages": [
                {"role": "system", "content": "You are a helpful assistant."},
                {"role": "user", "content": "Hello"},
                {"role": "assistant", "content": "Hi there!"},
                {"role": "user", "content": "How are you?"}
            ],
            "config": {
                "provider": "ollama",
                "model": "llama3"
            }
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::Chat { messages, .. } => {
                assert_eq!(messages.len(), 4);
                assert_eq!(messages[0].role, crate::llm::types::Role::System);
                assert_eq!(messages[3].role, crate::llm::types::Role::User);
            }
            _ => panic!("expected Chat variant"),
        }
    }

    #[test]
    fn deserialize_chat_with_tool_call_message() {
        let json = r#"{
            "type": "chat",
            "messages": [
                {
                    "role": "assistant",
                    "content": "",
                    "tool_calls": [
                        {
                            "id": "call_1",
                            "type": "function",
                            "function": {
                                "name": "read_file",
                                "arguments": "{\"path\": \"/tmp/test.rs\"}"
                            }
                        }
                    ]
                }
            ],
            "config": {
                "provider": "anthropic",
                "model": "claude-3-5-sonnet"
            }
        }"#;
        let req: WsRequest = serde_json::from_str(json).unwrap();
        match req {
            WsRequest::Chat { messages, .. } => {
                assert_eq!(messages.len(), 1);
                let tc = messages[0].tool_calls.as_ref().unwrap();
                assert_eq!(tc.len(), 1);
                assert_eq!(tc[0].function.name, "read_file");
            }
            _ => panic!("expected Chat variant"),
        }
    }

    // ── Pipeline state with agent assignment ────────────────────────

    #[test]
    fn pipeline_state_with_agent_converts_correctly() {
        let state = PipelineState {
            backlog: vec![],
            current: vec![UpcomingStory {
                story_id: "10_story_x".to_string(),
                name: Some("Story X".to_string()),
                error: None,
                merge_failure: None,
                agent: Some(crate::http::workflow::AgentAssignment {
                    agent_name: "coder-1".to_string(),
                    model: Some("claude-3-5-sonnet".to_string()),
                    status: "running".to_string(),
                }),
                review_hold: None,
                manual_qa: None,
            }],
            qa: vec![],
            merge: vec![],
            done: vec![],
        };
        let resp: WsResponse = state.into();
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["current"][0]["agent"]["agent_name"], "coder-1");
        assert_eq!(json["current"][0]["agent"]["model"], "claude-3-5-sonnet");
        assert_eq!(json["current"][0]["agent"]["status"], "running");
    }

    // ── Reconciliation progress done event ──────────────────────────

    #[test]
    fn reconciliation_done_event_has_empty_story_id() {
        let resp = WsResponse::ReconciliationProgress {
            story_id: String::new(),
            status: "done".to_string(),
            message: "Reconciliation complete".to_string(),
        };
        let json = serde_json::to_value(&resp).unwrap();
        assert_eq!(json["story_id"], "");
        assert_eq!(json["status"], "done");
    }

    // ── ws_handler integration tests (real WebSocket connection) ─────

    use futures::stream::SplitSink;
    use poem::EndpointExt;
    use tokio_tungstenite::tungstenite;

    /// Helper: construct a tungstenite text message from a string.
    fn ws_text(s: &str) -> tungstenite::Message {
        tungstenite::Message::Text(s.into())
    }

    /// Helper: start a poem server with ws_handler on an ephemeral port
    /// and return the WebSocket URL.
    async fn start_test_server() -> (String, Arc<AppContext>) {
        let tmp = tempfile::tempdir().unwrap();
        let root = tmp.path().to_path_buf();

        // Create minimal pipeline dirs so load_pipeline_state succeeds.
        for stage in &["1_backlog", "2_current", "3_qa", "4_merge"] {
            std::fs::create_dir_all(root.join(".story_kit").join("work").join(stage)).unwrap();
        }

        let ctx = Arc::new(AppContext::new_test(root));
        let ctx_data = ctx.clone();

        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
        let addr = listener.local_addr().unwrap();

        let app = poem::Route::new()
            .at("/ws", poem::get(ws_handler))
            .data(ctx_data);

        tokio::spawn(async move {
            let acceptor = poem::listener::TcpAcceptor::from_tokio(listener).unwrap();
            let _ = poem::Server::new_with_acceptor(acceptor)
                .run(app)
                .await;
        });

        // Small delay to let the server start.
        tokio::time::sleep(std::time::Duration::from_millis(50)).await;

        let url = format!("ws://127.0.0.1:{}/ws", addr.port());
        (url, ctx)
    }

    type WsSink = SplitSink<
        tokio_tungstenite::WebSocketStream<
            tokio_tungstenite::MaybeTlsStream<tokio::net::TcpStream>,
        >,
        tungstenite::Message,
    >;

    /// Helper: connect and return (sink, stream) plus read the initial
    /// pipeline_state and onboarding_status messages that are always sent
    /// on connect.
    async fn connect_ws(
        url: &str,
    ) -> (
        WsSink,
        futures::stream::SplitStream<
            tokio_tungstenite::WebSocketStream<
                tokio_tungstenite::MaybeTlsStream<tokio::net::TcpStream>,
            >,
        >,
        serde_json::Value,
    ) {
        let (ws, _resp) = tokio_tungstenite::connect_async(url).await.unwrap();
        let (sink, mut stream) = futures::StreamExt::split(ws);

        // The first message should be the initial pipeline_state.
        let first = tokio::time::timeout(std::time::Duration::from_secs(2), stream.next())
            .await
            .expect("timeout waiting for initial message")
            .expect("stream ended")
            .expect("ws error");

        let initial: serde_json::Value = match first {
            tungstenite::Message::Text(t) => serde_json::from_str(t.as_ref()).unwrap(),
            other => panic!("expected text message, got: {other:?}"),
        };

        // The second message is the onboarding_status — consume it so
        // callers only see application-level messages.
        let second = tokio::time::timeout(std::time::Duration::from_secs(2), stream.next())
            .await
            .expect("timeout waiting for onboarding_status")
            .expect("stream ended")
            .expect("ws error");
        let onboarding: serde_json::Value = match second {
            tungstenite::Message::Text(t) => serde_json::from_str(t.as_ref()).unwrap(),
            other => panic!("expected text message, got: {other:?}"),
        };
        assert_eq!(
            onboarding["type"], "onboarding_status",
            "expected onboarding_status, got: {onboarding}"
        );

        (sink, stream, initial)
    }

    /// Read next text message from the stream with a timeout.
    async fn next_msg(
        stream: &mut futures::stream::SplitStream<
            tokio_tungstenite::WebSocketStream<
                tokio_tungstenite::MaybeTlsStream<tokio::net::TcpStream>,
            >,
        >,
    ) -> serde_json::Value {
        let msg = tokio::time::timeout(std::time::Duration::from_secs(2), stream.next())
            .await
            .expect("timeout waiting for message")
            .expect("stream ended")
            .expect("ws error");
        match msg {
            tungstenite::Message::Text(t) => serde_json::from_str(t.as_ref()).unwrap(),
            other => panic!("expected text message, got: {other:?}"),
        }
    }

    #[tokio::test]
    async fn ws_handler_sends_initial_pipeline_state_on_connect() {
        let (url, _ctx) = start_test_server().await;
        let (_sink, _stream, initial) = connect_ws(&url).await;

        assert_eq!(initial["type"], "pipeline_state");
        // All stages should be empty arrays since no .md files were created.
        assert!(initial["backlog"].as_array().unwrap().is_empty());
        assert!(initial["current"].as_array().unwrap().is_empty());
        assert!(initial["qa"].as_array().unwrap().is_empty());
        assert!(initial["merge"].as_array().unwrap().is_empty());
    }

    #[tokio::test]
    async fn ws_handler_returns_error_for_invalid_json() {
        let (url, _ctx) = start_test_server().await;
        let (mut sink, mut stream, _initial) = connect_ws(&url).await;

        // Send invalid JSON.
        sink.send(ws_text("not valid json"))
            .await
            .unwrap();

        let msg = next_msg(&mut stream).await;
        assert_eq!(msg["type"], "error");
        assert!(
            msg["message"]
                .as_str()
                .unwrap()
                .contains("Invalid request"),
            "error message should indicate invalid request, got: {}",
            msg["message"]
        );
    }

    #[tokio::test]
    async fn ws_handler_returns_error_for_unknown_type() {
        let (url, _ctx) = start_test_server().await;
        let (mut sink, mut stream, _initial) = connect_ws(&url).await;

        // Send a message with an unknown type.
        sink.send(ws_text(r#"{"type": "bogus"}"#))
        .await
        .unwrap();

        let msg = next_msg(&mut stream).await;
        assert_eq!(msg["type"], "error");
        assert!(msg["message"].as_str().unwrap().contains("Invalid request"));
    }

    #[tokio::test]
    async fn ws_handler_cancel_outside_chat_does_not_error() {
        let (url, _ctx) = start_test_server().await;
        let (mut sink, mut stream, _initial) = connect_ws(&url).await;

        // Send cancel when no chat is active — should not produce an error.
        sink.send(ws_text(r#"{"type": "cancel"}"#))
        .await
        .unwrap();

        // Send another invalid message to check the connection is still alive.
        sink.send(ws_text("{}"))
            .await
            .unwrap();

        let msg = next_msg(&mut stream).await;
        // The invalid JSON message should produce an error, confirming
        // the cancel didn't break the connection.
        assert_eq!(msg["type"], "error");
    }

    #[tokio::test]
    async fn ws_handler_permission_response_outside_chat_is_ignored() {
        let (url, _ctx) = start_test_server().await;
        let (mut sink, mut stream, _initial) = connect_ws(&url).await;

        // Send permission response outside an active chat.
        sink.send(ws_text(
            r#"{"type": "permission_response", "request_id": "x", "approved": true}"#,
        ))
        .await
        .unwrap();

        // Send a probe message to check the connection is still alive.
        sink.send(ws_text("bad"))
            .await
            .unwrap();

        let msg = next_msg(&mut stream).await;
        assert_eq!(msg["type"], "error");
        assert!(msg["message"].as_str().unwrap().contains("Invalid request"));
    }

    #[tokio::test]
    async fn ws_handler_forwards_watcher_events() {
        let (url, ctx) = start_test_server().await;
        let (_sink, mut stream, _initial) = connect_ws(&url).await;

        // Broadcast a watcher event.
        ctx.watcher_tx
            .send(WatcherEvent::WorkItem {
                stage: "2_current".to_string(),
                item_id: "99_story_test".to_string(),
                action: "start".to_string(),
                commit_msg: "story-kit: start 99_story_test".to_string(),
            })
            .unwrap();

        let msg = next_msg(&mut stream).await;
        assert_eq!(msg["type"], "work_item_changed");
        assert_eq!(msg["item_id"], "99_story_test");
        assert_eq!(msg["stage"], "2_current");

        // After a work-item event, a pipeline_state refresh is pushed.
        let state_msg = next_msg(&mut stream).await;
        assert_eq!(state_msg["type"], "pipeline_state");
    }

    #[tokio::test]
    async fn ws_handler_forwards_config_changed_without_pipeline_refresh() {
        let (url, ctx) = start_test_server().await;
        let (_sink, mut stream, _initial) = connect_ws(&url).await;

        // Broadcast a config-changed event.
        ctx.watcher_tx.send(WatcherEvent::ConfigChanged).unwrap();

        let msg = next_msg(&mut stream).await;
        assert_eq!(msg["type"], "agent_config_changed");

        // Config-changed should NOT be followed by a pipeline_state refresh.
        // Send a probe to check no extra message is queued.
        ctx.watcher_tx.send(WatcherEvent::ConfigChanged).unwrap();
        let msg2 = next_msg(&mut stream).await;
        assert_eq!(msg2["type"], "agent_config_changed");
    }

    #[tokio::test]
    async fn ws_handler_forwards_reconciliation_events() {
        let (url, ctx) = start_test_server().await;
        let (_sink, mut stream, _initial) = connect_ws(&url).await;

        // Broadcast a reconciliation event.
        ctx.reconciliation_tx
            .send(crate::agents::ReconciliationEvent {
                story_id: "50_story_recon".to_string(),
                status: "checking".to_string(),
                message: "Checking story...".to_string(),
            })
            .unwrap();

        let msg = next_msg(&mut stream).await;
        assert_eq!(msg["type"], "reconciliation_progress");
        assert_eq!(msg["story_id"], "50_story_recon");
        assert_eq!(msg["status"], "checking");
        assert_eq!(msg["message"], "Checking story...");
    }

    #[tokio::test]
    async fn ws_handler_handles_client_disconnect_gracefully() {
        let (url, _ctx) = start_test_server().await;
        let (mut sink, _stream, _initial) = connect_ws(&url).await;

        // Close the connection — should not panic the server.
        sink.close().await.unwrap();

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

        // Connect again to verify server is still alive.
        let (_sink2, _stream2, initial2) = connect_ws(&url).await;
        assert_eq!(initial2["type"], "pipeline_state");
    }
}