use super::challenge::{update_server::UpdateServer, Empty, Keys, NodeUpdate};
use crate::{datastore::State, grpc::challenge::update_server::Update};
use detee_sgx::RaTlsConfig;
use rustls::pki_types::CertificateDer;
use std::{pin::Pin, sync::Arc};
use tokio::sync::broadcast::Sender;
use tokio_stream::{Stream, StreamExt};
use tonic::{Request, Response, Status, Streaming};

pub struct MyServer {
    state: Arc<State>,
    tx: Sender<NodeUpdate>,
    ratls_config: RaTlsConfig,
    keys: Keys, // For sending secret keys to new nodes ;)
}

impl MyServer {
    pub fn init(
        state: Arc<State>,
        keys: Keys,
        ratls_config: RaTlsConfig,
        tx: Sender<NodeUpdate>,
    ) -> Self {
        Self { state, tx, keys, ratls_config }
    }

    pub async fn start(self) {
        use detee_sgx::RaTlsConfigBuilder;
        use hyper::server::conn::http2::Builder;
        use hyper_util::{
            rt::{TokioExecutor, TokioIo},
            service::TowerToHyperService,
        };
        use std::sync::Arc;
        use tokio::net::TcpListener;
        use tokio_rustls::{rustls::ServerConfig, TlsAcceptor};
        use tonic::{body::boxed, service::Routes};
        use tower::{ServiceBuilder, ServiceExt};

        // TODO: error handling, shouldn't have expects

        let mut tls = ServerConfig::from_ratls_config(self.ratls_config.clone()).unwrap();
        tls.alpn_protocols = vec![b"h2".to_vec()];

        let state = self.state.clone();
        let svc = Routes::new(UpdateServer::new(self)).prepare();

        let http = Builder::new(TokioExecutor::new());

        let listener = TcpListener::bind("0.0.0.0:31373").await.expect("failed to bind listener");
        let tls_acceptor = TlsAcceptor::from(Arc::new(tls));

        loop {
            let (conn, addr) = match listener.accept().await {
                Ok(incoming) => incoming,
                Err(e) => {
                    println!("Error accepting connection: {}", e);
                    state.increase_net_attacks();
                    continue;
                }
            };

            let http = http.clone();
            let tls_acceptor = tls_acceptor.clone();
            let svc = svc.clone();

            let state = state.clone();
            tokio::spawn(async move {
                let mut certificates = Vec::new();

                let conn = tls_acceptor
                    .accept_with(conn, |info| {
                        if let Some(certs) = info.peer_certificates() {
                            for cert in certs {
                                certificates.push(cert.clone());
                            }
                        }
                    })
                    .await;

                let conn = if let Err(e) = conn {
                    println!("Error accepting TLS connection: {}", e);
                    state.increase_net_attacks();
                    return;
                } else {
                    conn.unwrap()
                };

                let extension_layer =
                    tower_http::add_extension::AddExtensionLayer::new(Arc::new(ConnInfo {
                        addr,
                        certificates,
                    }));
                let svc = ServiceBuilder::new().layer(extension_layer).service(svc);

                if let Err(e) = http
                    .serve_connection(
                        TokioIo::new(conn),
                        TowerToHyperService::new(
                            svc.map_request(|req: hyper::Request<_>| req.map(boxed)),
                        ),
                    )
                    .await
                {
                    println!("Error serving connection: {}", e);
                }
            });
        }
    }
}

#[derive(Debug)]
struct ConnInfo {
    addr: std::net::SocketAddr,
    certificates: Vec<CertificateDer<'static>>,
}

#[tonic::async_trait]
impl Update for MyServer {
    type GetUpdatesStream = Pin<Box<dyn Stream<Item = Result<NodeUpdate, Status>> + Send>>;

    async fn get_keys(&self, _request: Request<Empty>) -> Result<Response<Keys>, Status> {
        Ok(Response::new(self.keys.clone()))
    }

    async fn get_updates(
        &self,
        req: Request<Streaming<NodeUpdate>>,
    ) -> Result<Response<Self::GetUpdatesStream>, Status> {
        let conn_info = req.extensions().get::<Arc<ConnInfo>>().unwrap();
        self.state.increase_mratls_conns();
        let remote_ip = conn_info.addr.ip().to_string();
        let tx = self.tx.clone();
        let mut rx = self.tx.subscribe();
        let mut inbound = req.into_inner();
        let ds = self.state.clone();

        let stream = async_stream::stream! {
            let full_update_list: Vec<NodeUpdate> = ds.get_node_list().into_iter().map(Into::<NodeUpdate>::into).collect();
            for update in full_update_list {
                yield Ok(update);
            }

            loop {
                tokio::select! {
                    Some(msg) = inbound.next() => {
                        match msg {
                            Ok(mut update) => {
                                if update.ip == "localhost" {
                                    update.ip = remote_ip.clone();
                                    // note that we don't set this node online,
                                    // as it can be behind NAT
                                }
                                if update.ip != "127.0.0.1" && ds.process_node_update(update.clone().into()) && tx.send(update.clone()).is_err() {
                                    println!("tokio broadcast receivers had an issue consuming the channel");
                                };
                            }
                            Err(e) => {
                                yield Err(Status::internal(format!("Error receiving client stream: {}", e)));
                                break;
                            }
                        }
                    }
                    Ok(update) = rx.recv() => {
                        yield Ok(update);
                        // disconnect client if too many connections are active
                        if tx.receiver_count() > 9 {
                            yield Err(Status::internal("Already have too many clients. Connect to another server."));
                            return;
                        }
                    }

                }
            }
        };

        Ok(Response::new(Box::pin(stream) as Self::GetUpdatesStream))
    }
}