use crate::daemon::{events::Event, signals::Signal, DaemonResult};
use crate::xpc::interface::SERVICE_NAME;
use futures_util::StreamExt;
use std::collections::HashMap;
use std::ffi::CString;
use std::sync::Arc;
use tokio::sync::{mpsc, oneshot, Mutex};
use xpc_connection::{Message, MessageError, XpcClient, XpcListener};


static LOG_TARGET: &str = "xpc";

/// XPC IPC agent that forwards daemon events and signals over libxpc.
#[derive(Clone)]
pub struct XpcAgent {
    event_sink: mpsc::Sender<Event>,
    signal_receiver: Arc<Mutex<Option<mpsc::Receiver<Signal>>>>,
}

impl XpcAgent {
    /// Create a new XPC agent with an event sink and signal receiver.
    pub fn new(event_sink: mpsc::Sender<Event>, signal_receiver: mpsc::Receiver<Signal>) -> Self {
        Self {
            event_sink,
            signal_receiver: Arc::new(Mutex::new(Some(signal_receiver))),
        }
    }

    /// Run the XPC agent and host the XPC service. Implements `GetVersion`.
    pub async fn run(self) {
        log::info!(target: LOG_TARGET, "XPCAgent running");

        // Construct the Mach service name without a trailing NUL for CString.
        let service_name = SERVICE_NAME.trim_end_matches('\0');
        let mach_port_name = match CString::new(service_name) {
            Ok(c) => c,
            Err(e) => {
                log::error!(target: LOG_TARGET, "Invalid XPC service name: {e}");
                return;
            }
        };

        log::info!(
            target: LOG_TARGET,
            "Waiting for XPC connections on {}",
            service_name
        );

        let mut listener = XpcListener::listen(&mach_port_name);

        while let Some(client) = listener.next().await {
            tokio::spawn(handle_client(client));
        }

        log::info!(target: LOG_TARGET, "XPC listener shutting down");
    }

    /// Send an event to the daemon and await its reply.
    pub async fn send_event<T>(
        &self,
        make_event: impl FnOnce(crate::daemon::events::Reply<T>) -> Event,
    ) -> DaemonResult<T> {
        let (tx, rx) = oneshot::channel();
        self.event_sink
            .send(make_event(tx))
            .await
            .map_err(|_| "Failed to send event")?;
        rx.await.map_err(|_| "Failed to receive reply".into())
    }
}

async fn handle_client(mut client: XpcClient) {
    log::info!(target: LOG_TARGET, "New XPC connection");

    while let Some(message) = client.next().await {
        match message {
            Message::Error(MessageError::ConnectionInterrupted) => {
                log::warn!(target: LOG_TARGET, "XPC connection interrupted");
            }
            Message::Dictionary(map) => {
                // Try keys "method" or "type" to identify the call.
                let method_key = CString::new("method").unwrap();
                let type_key = CString::new("type").unwrap();

                let maybe_method = map
                    .get(&method_key)
                    .or_else(|| map.get(&type_key))
                    .and_then(|v| match v {
                        Message::String(s) => Some(s.to_string_lossy().into_owned()),
                        _ => None,
                    });

                match maybe_method.as_deref() {
                    Some("GetVersion") => {
                        let mut reply: HashMap<CString, Message> = HashMap::new();
                        reply.insert(
                            CString::new("type").unwrap(),
                            Message::String(CString::new("GetVersionResponse").unwrap()),
                        );
                        reply.insert(
                            CString::new("version").unwrap(),
                            Message::String(CString::new(env!("CARGO_PKG_VERSION")).unwrap()),
                        );
                        client.send_message(Message::Dictionary(reply));
                    }
                    Some(other) => {
                        log::warn!(target: LOG_TARGET, "Unknown XPC method: {}", other);
                        let mut reply: HashMap<CString, Message> = HashMap::new();
                        reply.insert(
                            CString::new("type").unwrap(),
                            Message::String(CString::new("Error").unwrap()),
                        );
                        reply.insert(
                            CString::new("error").unwrap(),
                            Message::String(CString::new("UnknownMethod").unwrap()),
                        );
                        reply.insert(
                            CString::new("message").unwrap(),
                            Message::String(CString::new(other).unwrap_or_else(|_| CString::new("").unwrap())),
                        );
                        client.send_message(Message::Dictionary(reply));
                    }
                    None => {
                        log::warn!(target: LOG_TARGET, "XPC message missing method/type");
                        let mut reply: HashMap<CString, Message> = HashMap::new();
                        reply.insert(
                            CString::new("type").unwrap(),
                            Message::String(CString::new("Error").unwrap()),
                        );
                        reply.insert(
                            CString::new("error").unwrap(),
                            Message::String(CString::new("InvalidRequest").unwrap()),
                        );
                        client.send_message(Message::Dictionary(reply));
                    }
                }
            }
            other => {
                // For now just echo any non-dictionary messages (useful for testing).
                log::info!(target: LOG_TARGET, "Echoing message: {:?}", other);
                client.send_message(other);
            }
        }
    }

    log::info!(target: LOG_TARGET, "XPC connection closed");
}