use crate::command_processor::*;
use crate::tools::*;
use serde::de::DeserializeOwned;
use std::cell::RefCell;
use std::net::SocketAddr;
use std::rc::Rc;
use stop_token::{future::FutureExt as _, StopSource, StopToken};

use veilid_tools::*;
cfg_if! {
    if #[cfg(feature="rt-async-std")] {
        use async_std::io::prelude::BufReadExt;
        use async_std::io::WriteExt;
        use async_std::io::BufReader;
    } else if #[cfg(feature="rt-tokio")] {
        use tokio::io::AsyncBufReadExt;
        use tokio::io::AsyncWriteExt;
        use tokio::io::BufReader;
    }
}

// fn map_to_internal_error<T: ToString>(e: T) -> VeilidAPIError {
//     VeilidAPIError::Internal {
//         message: e.to_string(),
//     }
// }

// fn decode_api_result<T: DeserializeOwned + fmt::Debug>(
//     reader: &api_result::Reader,
// ) -> VeilidAPIResult<T> {
//     match reader.which().map_err(map_to_internal_error)? {
//         api_result::Which::Ok(v) => {
//             let ok_val = v.map_err(map_to_internal_error)?;
//             let res: T = veilid_core::deserialize_json(ok_val).map_err(map_to_internal_error)?;
//             Ok(res)
//         }
//         api_result::Which::Err(e) => {
//             let err_val = e.map_err(map_to_internal_error)?;
//             let res: VeilidAPIError =
//                 veilid_core::deserialize_json(err_val).map_err(map_to_internal_error)?;
//             Err(res)
//         }
//     }
// }

// struct VeilidClientImpl {
//     comproc: CommandProcessor,
// }

// impl VeilidClientImpl {
//     pub fn new(comproc: CommandProcessor) -> Self {
//         Self { comproc }
//     }
// }

// }

struct ClientApiConnectionInner {
    comproc: CommandProcessor,
    connect_addr: Option<SocketAddr>,
    server: Option<flume::Sender<String>>,
    server_settings: Option<String>,
    disconnector: Option<StopSource>,
    disconnect_requested: bool,
    cancel_eventual: Eventual,
}

type Handle<T> = Rc<RefCell<T>>;

#[derive(Clone)]
pub struct ClientApiConnection {
    inner: Handle<ClientApiConnectionInner>,
}

impl ClientApiConnection {
    pub fn new(comproc: CommandProcessor) -> Self {
        Self {
            inner: Rc::new(RefCell::new(ClientApiConnectionInner {
                comproc,
                connect_addr: None,
                server: None,
                server_settings: None,
                disconnector: None,
                disconnect_requested: false,
                cancel_eventual: Eventual::new(),
            })),
        }
    }

    pub fn cancel(&self) {
        let eventual = {
            let inner = self.inner.borrow();
            inner.cancel_eventual.clone()
        };
        eventual.resolve(); // don't need to await this
    }

    // async fn process_veilid_state<'a>(
    //     &'a mut self,
    //     veilid_state: VeilidState,
    // ) -> Result<(), String> {
    //     let mut inner = self.inner.borrow_mut();
    //     inner.comproc.update_attachment(veilid_state.attachment);
    //     inner.comproc.update_network_status(veilid_state.network);
    //     inner.comproc.update_config(veilid_state.config);
    //     Ok(())
    // }

    async fn process_update(&self, update: json::JsonValue) {
        let comproc = self.inner.borrow().comproc.clone();
        let Some(kind) = update["kind"].as_str() else {
            comproc.log_message(format!("missing update kind: {}", update));
            return;
        };
        match kind {
            "Log" => {
                comproc.update_log(update);
            }
            "AppMessage" => {
                comproc.update_app_message(update);
            }
            "AppCall" => {
                comproc.update_app_call(update);
            }
            "Attachment" => {
                comproc.update_attachment(update);
            }
            "Network" => {
                comproc.update_network_status(update);
            }
            "Config" => {
                comproc.update_config(update);
            }
            "RouteChange" => {
                comproc.update_route(update);
            }
            "Shutdown" => comproc.update_shutdown(),
            "ValueChange" => {
                comproc.update_value_change(update);
            }
            _ => {
                comproc.log_message(format!("unknown update kind: {}", update));
            }
        }
    }

    // async fn spawn_rpc_system(
    //     &mut self,
    //     connect_addr: SocketAddr,
    //     mut rpc_system: RpcSystem<rpc_twoparty_capnp::Side>,
    // ) -> Result<(), String> {
    //     let mut request;
    //     {
    //         let mut inner = self.inner.borrow_mut();

    //         // Get the bootstrap server connection object
    //         inner.server = Some(Rc::new(RefCell::new(
    //             rpc_system.bootstrap(rpc_twoparty_capnp::Side::Server),
    //         )));

    //         // Store our disconnector future for later (must happen after bootstrap, contrary to documentation)
    //         inner.disconnector = Some(rpc_system.get_disconnector());

    //         // Get a client object to pass to the server for status update callbacks
    //         let client = capnp_rpc::new_client(VeilidClientImpl::new(inner.comproc.clone()));

    //         // Register our client and get a registration object back
    //         request = inner
    //             .server
    //             .as_ref()
    //             .unwrap()
    //             .borrow_mut()
    //             .register_request();
    //         request.get().set_veilid_client(client);

    //         inner
    //             .comproc
    //             .set_connection_state(ConnectionState::Connected(
    //                 connect_addr,
    //                 std::time::SystemTime::now(),
    //             ));
    //     }

    //     let rpc_jh = spawn_local(rpc_system);

    //     let reg_res: Result<registration::Client, String> = (async {
    //         // Send the request and get the state object and the registration object
    //         let response = request
    //             .send()
    //             .promise
    //             .await
    //             .map_err(|e| format!("failed to send register request: {}", e))?;
    //         let response = response
    //             .get()
    //             .map_err(|e| format!("failed to get register response: {}", e))?;

    //         // Get the registration object, which drops our connection when it is dropped
    //         let registration = response
    //             .get_registration()
    //             .map_err(|e| format!("failed to get registration object: {}", e))?;

    //         // Get the initial veilid state
    //         let veilid_state = response
    //             .get_state()
    //             .map_err(|e| format!("failed to get initial veilid state: {}", e))?;

    //         // Set up our state for the first time
    //         let veilid_state: VeilidState = deserialize_json(veilid_state)
    //             .map_err(|e| format!("failed to get deserialize veilid state: {}", e))?;
    //         self.process_veilid_state(veilid_state).await?;

    //         // Save server settings
    //         let server_settings = response
    //             .get_settings()
    //             .map_err(|e| format!("failed to get initial veilid server settings: {}", e))?
    //             .to_owned();
    //         self.inner.borrow_mut().server_settings = Some(server_settings.clone());

    //         // Don't drop the registration, doing so will remove the client
    //         // object mapping from the server which we need for the update backchannel
    //         Ok(registration)
    //     })
    //     .await;

    //     let _registration = match reg_res {
    //         Ok(v) => v,
    //         Err(e) => {
    //             rpc_jh.abort().await;
    //             return Err(e);
    //         }
    //     };

    //     // Wait until rpc system completion or disconnect was requested
    //     let res = rpc_jh.await;
    //     res.map_err(|e| format!("client RPC system error: {}", e))
    // }

    async fn handle_connection(&mut self, connect_addr: SocketAddr) -> Result<(), String> {
        trace!("ClientApiConnection::handle_connection");

        let stop_token = {
            let stop_source = StopSource::new();
            let token = stop_source.token();
            let mut inner = self.inner.borrow_mut();
            inner.connect_addr = Some(connect_addr);
            inner.disconnector = Some(stop_source);
            token
        };

        // Connect the TCP socket
        let stream = TcpStream::connect(connect_addr)
            .await
            .map_err(map_to_string)?;

        // If it succeed, disable nagle algorithm
        stream.set_nodelay(true).map_err(map_to_string)?;

        // Split the stream
        cfg_if! {
            if #[cfg(feature="rt-async-std")] {
                use futures::AsyncReadExt;
                let (reader, writer) = stream.split();
                let mut reader = BufReader::new(reader);
            } else if #[cfg(feature="rt-tokio")] {
                let (reader, writer) = stream.into_split();
                let mut reader = BufReader::new(reader);
            }
        }

        // Process lines
        let mut line = String::new();
        while let Ok(r) = reader
            .read_line(&mut line)
            .timeout_at(stop_token.clone())
            .await
        {
            match r {
                Ok(size) => {
                    // Exit on EOF
                    if size == 0 {
                        // Disconnected
                        return Err("Connection closed".to_owned());
                    }
                }
                Err(e) => {
                    // Disconnected
                    return Err("Connection lost".to_owned());
                }
            }

            // Unmarshal json
            let j = match json::parse(line.trim()) {
                Ok(v) => v,
                Err(e) => {
                    error!("failed to parse server response: {}", e);
                    continue;
                }
            };

            if j["type"] == "Update" {
                self.process_update(j).await;
            }
        }

        // Connection finished
        Ok(())

        // let rpc_network = Box::new(twoparty::VatNetwork::new(
        //     reader,
        //     writer,
        //     rpc_twoparty_capnp::Side::Client,
        //     Default::default(),
        // ));

        // // Create the rpc system
        // let rpc_system = RpcSystem::new(rpc_network, None);

        // // Process the rpc system until we decide we're done
        // match self.spawn_rpc_system(connect_addr, rpc_system).await {
        //     Ok(()) => {}
        //     Err(e) => {
        //         error!("Failed to spawn client RPC system: {}", e);
        //     }
        // }

        // // Drop the server and disconnector too (if we still have it)
        // let mut inner = self.inner.borrow_mut();
        // let disconnect_requested = inner.disconnect_requested;
        // inner.server_settings = None;
        // inner.server = None;
        // inner.disconnector = None;
        // inner.disconnect_requested = false;
        // inner.connect_addr = None;
    }

    // pub fn cancellable<T>(&mut self, p: Promise<T, capnp::Error>) -> Promise<T, capnp::Error>
    // where
    //     T: 'static,
    // {
    //     let (mut cancel_instance, cancel_eventual) = {
    //         let inner = self.inner.borrow();
    //         (
    //             inner.cancel_eventual.instance_empty().fuse(),
    //             inner.cancel_eventual.clone(),
    //         )
    //     };
    //     let mut p = p.fuse();

    //     Promise::from_future(async move {
    //         let out = select! {
    //             a = p => {
    //                 a
    //             },
    //             _ = cancel_instance => {
    //                 Err(capnp::Error::failed("cancelled".into()))
    //             }
    //         };
    //         drop(cancel_instance);
    //         cancel_eventual.reset();
    //         out
    //     })
    // }

    pub async fn server_attach(&mut self) -> Result<(), String> {
        trace!("ClientApiConnection::server_attach");
        let server = {
            let inner = self.inner.borrow();
            inner
                .server
                .as_ref()
                .ok_or_else(|| "Not connected, ignoring attach request".to_owned())?
                .clone()
        };
        let request = server.borrow().attach_request();
        let response = self
            .cancellable(request.send().promise)
            .await
            .map_err(map_to_string)?;
        let reader = response
            .get()
            .map_err(map_to_string)?
            .get_result()
            .map_err(map_to_string)?;
        let res: VeilidAPIResult<()> = decode_api_result(&reader);
        res.map_err(map_to_string)
    }

    pub async fn server_detach(&mut self) -> Result<(), String> {
        trace!("ClientApiConnection::server_detach");
        let server = {
            let inner = self.inner.borrow();
            inner
                .server
                .as_ref()
                .ok_or_else(|| "Not connected, ignoring detach request".to_owned())?
                .clone()
        };
        let request = server.borrow().detach_request();
        let response = self
            .cancellable(request.send().promise)
            .await
            .map_err(map_to_string)?;
        let reader = response
            .get()
            .map_err(map_to_string)?
            .get_result()
            .map_err(map_to_string)?;
        let res: VeilidAPIResult<()> = decode_api_result(&reader);
        res.map_err(map_to_string)
    }

    pub async fn server_shutdown(&mut self) -> Result<(), String> {
        trace!("ClientApiConnection::server_shutdown");
        let server = {
            let inner = self.inner.borrow();
            inner
                .server
                .as_ref()
                .ok_or_else(|| "Not connected, ignoring attach request".to_owned())?
                .clone()
        };
        let request = server.borrow().shutdown_request();
        let response = self
            .cancellable(request.send().promise)
            .await
            .map_err(map_to_string)?;
        response.get().map(drop).map_err(map_to_string)
    }

    pub async fn server_debug(&mut self, what: String) -> Result<String, String> {
        trace!("ClientApiConnection::server_debug");
        let server = {
            let inner = self.inner.borrow();
            inner
                .server
                .as_ref()
                .ok_or_else(|| "Not connected, ignoring debug request".to_owned())?
                .clone()
        };
        let mut request = server.borrow().debug_request();
        request.get().set_command(&what);
        let response = self
            .cancellable(request.send().promise)
            .await
            .map_err(map_to_string)?;
        let reader = response
            .get()
            .map_err(map_to_string)?
            .get_result()
            .map_err(map_to_string)?;
        let res: VeilidAPIResult<String> = decode_api_result(&reader);
        res.map_err(map_to_string)
    }

    pub async fn server_change_log_level(
        &mut self,
        layer: String,
        log_level: VeilidConfigLogLevel,
    ) -> Result<(), String> {
        trace!("ClientApiConnection::change_log_level");
        let server = {
            let inner = self.inner.borrow();
            inner
                .server
                .as_ref()
                .ok_or_else(|| "Not connected, ignoring change_log_level request".to_owned())?
                .clone()
        };
        let mut request = server.borrow().change_log_level_request();
        request.get().set_layer(&layer);
        let log_level_json = veilid_core::serialize_json(&log_level);
        request.get().set_log_level(&log_level_json);
        let response = self
            .cancellable(request.send().promise)
            .await
            .map_err(map_to_string)?;
        let reader = response
            .get()
            .map_err(map_to_string)?
            .get_result()
            .map_err(map_to_string)?;
        let res: VeilidAPIResult<()> = decode_api_result(&reader);
        res.map_err(map_to_string)
    }

    pub async fn server_appcall_reply(
        &mut self,
        id: OperationId,
        msg: Vec<u8>,
    ) -> Result<(), String> {
        trace!("ClientApiConnection::appcall_reply");
        let server = {
            let inner = self.inner.borrow();
            inner
                .server
                .as_ref()
                .ok_or_else(|| "Not connected, ignoring change_log_level request".to_owned())?
                .clone()
        };
        let mut request = server.borrow().app_call_reply_request();
        request.get().set_id(id.as_u64());
        request.get().set_message(&msg);
        let response = self
            .cancellable(request.send().promise)
            .await
            .map_err(map_to_string)?;
        let reader = response
            .get()
            .map_err(map_to_string)?
            .get_result()
            .map_err(map_to_string)?;
        let res: VeilidAPIResult<()> = decode_api_result(&reader);
        res.map_err(map_to_string)
    }

    // Start Client API connection
    pub async fn connect(&mut self, connect_addr: SocketAddr) -> Result<(), String> {
        trace!("ClientApiConnection::connect");
        // Save the address to connect to
        self.handle_connection(connect_addr).await
    }

    // End Client API connection
    pub async fn disconnect(&mut self) {
        trace!("ClientApiConnection::disconnect");
        let disconnector = self.inner.borrow_mut().disconnector.take();
        match disconnector {
            Some(d) => {
                self.inner.borrow_mut().disconnect_requested = true;
                d.await.unwrap();
            }
            None => {
                debug!("disconnector doesn't exist");
            }
        }
    }
}