use super::{
    GatewayState,
    session::{Session, handle_in_chat_command, schedule_background_history_compaction},
};
use crate::agent::EmittedMessageHandler;
use crate::bus::ChatMessage;
use crate::bus::message::{ToolMessageState, format_tool_call_content};
use crate::protocol::{SessionSummary, WsInbound, WsOutbound, parse_inbound, serialize_outbound};
use async_trait::async_trait;
use axum::extract::State;
use axum::extract::ws::{Message as WsMessage, WebSocket, WebSocketUpgrade};
use axum::response::Response;
use futures_util::{SinkExt, StreamExt};
use std::sync::Arc;
use tokio::sync::{Mutex, mpsc};

struct WsToolCallEmitter {
    sender: mpsc::Sender<WsOutbound>,
    show_tool_results: bool,
}

#[async_trait]
impl EmittedMessageHandler for WsToolCallEmitter {
    async fn handle(&self, message: ChatMessage) {
        if !should_display_message_to_user(self.show_tool_results, &message) {
            return;
        }

        for outbound in ws_outbound_from_chat_message(&message) {
            let _ = self.sender.send(outbound).await;
        }
    }
}

pub async fn ws_handler(ws: WebSocketUpgrade, State(state): State<Arc<GatewayState>>) -> Response {
    ws.on_upgrade(|socket| async {
        handle_socket(socket, state).await;
    })
}

async fn handle_socket(ws: WebSocket, state: Arc<GatewayState>) {
    let (sender, receiver) = mpsc::channel::<WsOutbound>(100);

    let provider_config = match state.config.get_provider_config("default") {
        Ok(cfg) => cfg,
        Err(e) => {
            tracing::error!(error = %e, "Failed to get provider config");
            return;
        }
    };

    let initial_record = match state.session_manager.create_cli_session(None) {
        Ok(record) => record,
        Err(e) => {
            tracing::error!(error = %e, "Failed to create initial CLI session");
            return;
        }
    };

    let channel_name = "cli".to_string();

    // 创建 CLI session
    let session = match Session::new(
        channel_name.clone(),
        provider_config,
        sender,
        state.session_manager.tools(),
        state.session_manager.skills(),
        state.session_manager.store(),
        state.config.gateway.agent_prompt_reinject_every,
    )
    .await
    {
        Ok(s) => Arc::new(Mutex::new(s)),
        Err(e) => {
            tracing::error!(error = %e, "Failed to create session");
            return;
        }
    };

    if let Err(e) = session.lock().await.ensure_chat_loaded(&initial_record.id) {
        tracing::error!(error = %e, session_id = %initial_record.id, "Failed to load initial CLI session history");
        return;
    }

    let runtime_session_id = session.lock().await.id.to_string();
    let mut current_session_id = initial_record.id.clone();
    tracing::info!(runtime_session_id = %runtime_session_id, session_id = %current_session_id, "CLI session established");

    let _ = session
        .lock()
        .await
        .send(WsOutbound::SessionEstablished {
            session_id: current_session_id.clone(),
        })
        .await;

    let (mut ws_sender, mut ws_receiver) = ws.split();

    let mut receiver = receiver;
    let session_id_for_sender = runtime_session_id.clone();
    tokio::spawn(async move {
        while let Some(msg) = receiver.recv().await {
            if let Ok(text) = serialize_outbound(&msg) {
                if ws_sender.send(WsMessage::Text(text.into())).await.is_err() {
                    #[cfg(debug_assertions)]
                    tracing::debug!(session_id = %session_id_for_sender, "WebSocket send error");
                    break;
                }
            }
        }
    });

    while let Some(msg) = ws_receiver.next().await {
        match msg {
            Ok(WsMessage::Text(text)) => {
                let text = text.to_string();
                match parse_inbound(&text) {
                    Ok(inbound) => {
                        if let Err(e) = handle_inbound(
                            &state,
                            &session,
                            &runtime_session_id,
                            &mut current_session_id,
                            inbound,
                        )
                        .await
                        {
                            tracing::warn!(error = %e, session_id = %current_session_id, "Failed to handle inbound message");
                            let _ = session
                                .lock()
                                .await
                                .send(WsOutbound::Error {
                                    code: "SESSION_ERROR".to_string(),
                                    message: e.to_string(),
                                })
                                .await;
                        }
                    }
                    Err(e) => {
                        tracing::warn!(error = %e, "Failed to parse inbound message");
                        let _ = session
                            .lock()
                            .await
                            .send(WsOutbound::Error {
                                code: "PARSE_ERROR".to_string(),
                                message: e.to_string(),
                            })
                            .await;
                    }
                }
            }
            Ok(WsMessage::Close(_)) | Err(_) => {
                #[cfg(debug_assertions)]
                tracing::debug!(session_id = %runtime_session_id, "WebSocket closed");
                break;
            }
            _ => {}
        }
    }

    tracing::info!(session_id = %runtime_session_id, current_session_id = %current_session_id, "CLI session ended");
}

fn to_session_summary(record: crate::storage::SessionRecord) -> SessionSummary {
    SessionSummary {
        session_id: record.id,
        title: record.title,
        channel_name: record.channel_name,
        chat_id: record.chat_id,
        message_count: record.message_count,
        last_active_at: record.last_active_at,
        archived_at: record.archived_at,
    }
}

fn ws_outbound_from_chat_message(message: &ChatMessage) -> Vec<WsOutbound> {
    match message.role.as_str() {
        "assistant" => {
            if let Some(tool_calls) = &message.tool_calls {
                let mut outbound = Vec::new();
                if !message.content.trim().is_empty() {
                    outbound.push(WsOutbound::AssistantResponse {
                        id: message.id.clone(),
                        content: message.content.clone(),
                        role: message.role.clone(),
                    });
                }

                outbound.extend(tool_calls.iter().map(|tool_call| WsOutbound::ToolCall {
                    id: message.id.clone(),
                    tool_call_id: tool_call.id.clone(),
                    tool_name: tool_call.name.clone(),
                    arguments: tool_call.arguments.clone(),
                    content: format_tool_call_content(&tool_call.name, &tool_call.arguments),
                    role: message.role.clone(),
                }));
                outbound
            } else {
                vec![WsOutbound::AssistantResponse {
                    id: message.id.clone(),
                    content: message.content.clone(),
                    role: message.role.clone(),
                }]
            }
        }
        "tool" => match message
            .tool_state
            .as_ref()
            .unwrap_or(&ToolMessageState::Completed)
        {
            ToolMessageState::Completed => vec![WsOutbound::ToolResult {
                id: message.id.clone(),
                tool_call_id: message.tool_call_id.clone().unwrap_or_default(),
                tool_name: message.tool_name.clone().unwrap_or_default(),
                content: message.content.clone(),
                role: message.role.clone(),
            }],
            ToolMessageState::PendingUserAction => vec![WsOutbound::ToolPending {
                id: message.id.clone(),
                tool_call_id: message.tool_call_id.clone().unwrap_or_default(),
                tool_name: message.tool_name.clone().unwrap_or_default(),
                content: message.content.clone(),
                role: message.role.clone(),
                resume_hint: "完成外部操作后，直接发一条继续消息即可。".to_string(),
            }],
        },
        _ => Vec::new(),
    }
}

fn should_display_message_to_user(show_tool_results: bool, message: &ChatMessage) -> bool {
    if message.role != "tool" {
        return true;
    }

    show_tool_results
        || matches!(
            message
                .tool_state
                .as_ref()
                .unwrap_or(&ToolMessageState::Completed),
            ToolMessageState::PendingUserAction
        )
}

async fn handle_inbound(
    state: &Arc<GatewayState>,
    session: &Arc<Mutex<Session>>,
    runtime_session_id: &str,
    current_session_id: &mut String,
    inbound: WsInbound,
) -> Result<(), crate::agent::AgentError> {
    match inbound {
        WsInbound::UserInput {
            content,
            chat_id,
            sender_id,
            ..
        } => {
            let chat_id = chat_id.unwrap_or_else(|| current_session_id.clone());
            let sender_id = resolve_ws_sender_id(sender_id.as_deref(), runtime_session_id);
            let (history, agent, user_tx) = {
                let mut session_guard = session.lock().await;

                session_guard.ensure_persistent_session(&chat_id)?;
                session_guard.ensure_chat_loaded(&chat_id)?;

                if let Some(command_response) =
                    handle_in_chat_command(&mut session_guard, &chat_id, &content)?
                {
                    let _ = session_guard
                        .send(WsOutbound::AssistantResponse {
                            id: uuid::Uuid::new_v4().to_string(),
                            content: command_response,
                            role: "assistant".to_string(),
                        })
                        .await;
                    return Ok(());
                }

                session_guard.ensure_agent_prompt_before_user_message(&chat_id)?;

                let user_message = session_guard.create_user_message(&content, Vec::new());
                let user_message_id = user_message.id.clone();
                session_guard.append_persisted_message(&chat_id, user_message)?;

                let history = session_guard.get_or_create_history(&chat_id).clone();
                session_guard.record_skill_offer(&chat_id)?;

                let live_emitter = Arc::new(WsToolCallEmitter {
                    sender: session_guard.user_tx.clone(),
                    show_tool_results: state.config.gateway.show_tool_results,
                });
                let agent = session_guard
                    .create_agent(&chat_id, Some(&sender_id), Some(&user_message_id))?
                    .with_emitted_message_handler(live_emitter);

                (history, agent, session_guard.user_tx.clone())
            };

            match agent.process(history).await {
                Ok(result) => {
                    let mut session_guard = session.lock().await;
                    session_guard
                        .append_persisted_messages(&chat_id, result.emitted_messages.clone())?;
                    for outbound in result
                        .emitted_messages
                        .iter()
                        .filter(|message| {
                            !message.is_assistant_tool_call_message()
                                && should_display_message_to_user(
                                    state.config.gateway.show_tool_results,
                                    message,
                                )
                        })
                        .flat_map(ws_outbound_from_chat_message)
                    {
                        let _ = session_guard.send(outbound).await;
                    }

                    drop(session_guard);

                    if let Err(error) =
                        schedule_background_history_compaction(session.clone(), chat_id.clone())
                            .await
                    {
                        tracing::warn!(chat_id = %chat_id, error = %error, "Failed to schedule background history compaction for CLI session");
                    }
                }
                Err(error) => {
                    tracing::error!(chat_id = %chat_id, error = %error, "Agent process error");
                    let _ = user_tx
                        .send(WsOutbound::Error {
                            code: "LLM_ERROR".to_string(),
                            message: error.to_string(),
                        })
                        .await;
                }
            }

            Ok(())
        }
        WsInbound::ClearHistory {
            session_id,
            chat_id,
        } => {
            let target = session_id
                .or(chat_id)
                .unwrap_or_else(|| current_session_id.clone());
            state.session_manager.clear_session_messages(&target)?;

            let mut session_guard = session.lock().await;
            session_guard.remove_history(&target);
            let _ = session_guard
                .send(WsOutbound::HistoryCleared { session_id: target })
                .await;
            Ok(())
        }
        WsInbound::CreateSession { title } => {
            let record = state.session_manager.create_cli_session(title.as_deref())?;
            *current_session_id = record.id.clone();

            let mut session_guard = session.lock().await;
            session_guard.ensure_chat_loaded(&record.id)?;
            let _ = session_guard
                .send(WsOutbound::SessionCreated {
                    session_id: record.id,
                    title: record.title,
                })
                .await;
            Ok(())
        }
        WsInbound::ListSessions { include_archived } => {
            let records = state.session_manager.list_cli_sessions(include_archived)?;
            let summaries = records.into_iter().map(to_session_summary).collect();

            let session_guard = session.lock().await;
            let _ = session_guard
                .send(WsOutbound::SessionList {
                    sessions: summaries,
                    current_session_id: Some(current_session_id.clone()),
                })
                .await;
            Ok(())
        }
        WsInbound::LoadSession { session_id } => {
            let Some(record) = state.session_manager.get_session_record(&session_id)? else {
                let session_guard = session.lock().await;
                let _ = session_guard
                    .send(WsOutbound::Error {
                        code: "SESSION_NOT_FOUND".to_string(),
                        message: format!("Session not found: {}", session_id),
                    })
                    .await;
                return Ok(());
            };

            *current_session_id = record.id.clone();
            let mut session_guard = session.lock().await;
            session_guard.ensure_chat_loaded(&record.id)?;
            let _ = session_guard
                .send(WsOutbound::SessionLoaded {
                    session_id: record.id,
                    title: record.title,
                    message_count: record.message_count,
                })
                .await;
            Ok(())
        }
        WsInbound::RenameSession { session_id, title } => {
            let target = session_id.unwrap_or_else(|| current_session_id.clone());
            state.session_manager.rename_session(&target, &title)?;
            let session_guard = session.lock().await;
            let _ = session_guard
                .send(WsOutbound::SessionRenamed {
                    session_id: target,
                    title,
                })
                .await;
            Ok(())
        }
        WsInbound::ArchiveSession { session_id } => {
            let target = session_id.unwrap_or_else(|| current_session_id.clone());
            state.session_manager.archive_session(&target)?;
            let session_guard = session.lock().await;
            let _ = session_guard
                .send(WsOutbound::SessionArchived { session_id: target })
                .await;
            Ok(())
        }
        WsInbound::DeleteSession { session_id } => {
            let target = session_id.unwrap_or_else(|| current_session_id.clone());
            state.session_manager.delete_session(&target)?;

            let replacement = if target == *current_session_id {
                Some(state.session_manager.create_cli_session(None)?)
            } else {
                None
            };

            let mut session_guard = session.lock().await;
            session_guard.remove_history(&target);
            let _ = session_guard
                .send(WsOutbound::SessionDeleted {
                    session_id: target.clone(),
                })
                .await;

            if let Some(record) = replacement {
                *current_session_id = record.id.clone();
                session_guard.ensure_chat_loaded(&record.id)?;
                let _ = session_guard
                    .send(WsOutbound::SessionCreated {
                        session_id: record.id,
                        title: record.title,
                    })
                    .await;
            }

            Ok(())
        }
        WsInbound::Ping => {
            let session_guard = session.lock().await;
            let _ = session_guard.send(WsOutbound::Pong).await;
            Ok(())
        }
    }
}

fn resolve_ws_sender_id(sender_id: Option<&str>, runtime_session_id: &str) -> String {
    sender_id
        .map(str::trim)
        .filter(|sender_id| !sender_id.is_empty())
        .map(ToOwned::to_owned)
        .unwrap_or_else(|| runtime_session_id.to_string())
}

#[cfg(test)]
mod tests {
    use super::{
        WsToolCallEmitter, resolve_ws_sender_id, should_display_message_to_user,
        ws_outbound_from_chat_message,
    };
    use crate::agent::EmittedMessageHandler;
    use crate::bus::ChatMessage;
    use crate::bus::message::ToolMessageState;
    use crate::protocol::WsOutbound;
    use crate::providers::ToolCall;
    use serde_json::json;
    use tokio::sync::mpsc;

    #[test]
    fn test_ws_outbound_from_chat_message_expands_tool_calls() {
        let message = ChatMessage::assistant_with_tool_calls(
            "",
            vec![ToolCall {
                id: "call-1".to_string(),
                name: "calculator".to_string(),
                arguments: json!({"expression": "1 + 1"}),
            }],
        );

        let outbound = ws_outbound_from_chat_message(&message);

        assert_eq!(outbound.len(), 1);
        match &outbound[0] {
            WsOutbound::ToolCall {
                tool_call_id,
                tool_name,
                arguments,
                content,
                ..
            } => {
                assert_eq!(tool_call_id, "call-1");
                assert_eq!(tool_name, "calculator");
                assert_eq!(arguments["expression"], "1 + 1");
                assert_eq!(content, "### calculator\n- expression: 1 + 1");
            }
            other => panic!("unexpected outbound variant: {:?}", other),
        }
    }

    #[test]
    fn test_ws_outbound_keeps_assistant_content_when_tool_calls_exist() {
        let message = ChatMessage::assistant_with_tool_calls(
            "日报已整理完成。",
            vec![ToolCall {
                id: "call-1".to_string(),
                name: "memory_manage".to_string(),
                arguments: json!({"action": "put"}),
            }],
        );

        let outbound = ws_outbound_from_chat_message(&message);

        assert_eq!(outbound.len(), 2);
        assert!(matches!(outbound[0], WsOutbound::AssistantResponse { .. }));
        assert!(matches!(outbound[1], WsOutbound::ToolCall { .. }));
    }

    #[test]
    fn test_ws_outbound_from_chat_message_includes_tool_results() {
        let message = ChatMessage::tool("call-1", "calculator", "2");

        let outbound = ws_outbound_from_chat_message(&message);

        assert_eq!(outbound.len(), 1);
        assert!(matches!(outbound[0], WsOutbound::ToolResult { .. }));
    }

    #[test]
    fn test_ws_outbound_from_chat_message_includes_tool_pending() {
        let message = ChatMessage::tool_with_state(
            "call-1",
            "bash",
            "等待你完成授权后再继续。",
            ToolMessageState::PendingUserAction,
        );

        let outbound = ws_outbound_from_chat_message(&message);

        assert_eq!(outbound.len(), 1);
        assert!(matches!(outbound[0], WsOutbound::ToolPending { .. }));
    }

    #[test]
    fn test_should_display_message_to_user_hides_completed_tool_results_by_default() {
        let completed = ChatMessage::tool("call-1", "calculator", "2");
        let pending = ChatMessage::tool_with_state(
            "call-2",
            "bash",
            "waiting",
            ToolMessageState::PendingUserAction,
        );

        assert!(!should_display_message_to_user(false, &completed));
        assert!(should_display_message_to_user(false, &pending));
        assert!(should_display_message_to_user(true, &completed));
    }

    #[test]
    fn test_resolve_ws_sender_id_prefers_inbound_sender() {
        assert_eq!(
            resolve_ws_sender_id(Some("user-42"), "runtime-1"),
            "user-42"
        );
        assert_eq!(
            resolve_ws_sender_id(Some("  user-42  "), "runtime-1"),
            "user-42"
        );
    }

    #[test]
    fn test_resolve_ws_sender_id_falls_back_to_runtime_session_id() {
        assert_eq!(resolve_ws_sender_id(None, "runtime-1"), "runtime-1");
        assert_eq!(resolve_ws_sender_id(Some("   "), "runtime-1"), "runtime-1");
    }

    #[tokio::test]
    async fn test_ws_tool_call_emitter_hides_completed_tool_results_when_disabled() {
        let (sender, mut receiver) = mpsc::channel(4);
        let emitter = WsToolCallEmitter {
            sender,
            show_tool_results: false,
        };

        emitter
            .handle(ChatMessage::tool("call-1", "calculator", "2"))
            .await;

        assert!(
            tokio::time::timeout(std::time::Duration::from_millis(50), receiver.recv())
                .await
                .is_err()
        );
    }
}