1 files changed, 304 insertions, 0 deletions
diff --git a/planetwars-server/src/modules/client_api.rs b/planetwars-server/src/modules/client_api.rs
new file mode 100644
index 0000000..7026671
--- /dev/null
+++ b/planetwars-server/src/modules/client_api.rs
@@ -0,0 +1,304 @@
+pub mod pb {
+    tonic::include_proto!("grpc.planetwars.client_api");
+
+    pub use player_api_client_message::ClientMessage as PlayerApiClientMessageType;
+    pub use player_api_server_message::ServerMessage as PlayerApiServerMessageType;
+}
+
+use std::collections::HashMap;
+use std::net::SocketAddr;
+use std::sync::{Arc, Mutex};
+use std::time::Duration;
+
+use runner::match_context::{EventBus, PlayerHandle, RequestError, RequestMessage};
+use runner::match_log::MatchLogger;
+use tokio::sync::{mpsc, oneshot};
+use tokio_stream::wrappers::UnboundedReceiverStream;
+use tonic;
+use tonic::transport::Server;
+use tonic::{Request, Response, Status, Streaming};
+
+use planetwars_matchrunner as runner;
+
+use crate::db;
+use crate::util::gen_alphanumeric;
+use crate::ConnectionPool;
+use crate::GlobalConfig;
+
+use super::matches::{MatchPlayer, RunMatch};
+
+pub struct ClientApiServer {
+    conn_pool: ConnectionPool,
+    runner_config: Arc<GlobalConfig>,
+    router: PlayerRouter,
+}
+
+/// Routes players to their handler
+#[derive(Clone)]
+struct PlayerRouter {
+    routing_table: Arc<Mutex<HashMap<String, SyncThingData>>>,
+}
+
+impl PlayerRouter {
+    pub fn new() -> Self {
+        PlayerRouter {
+            routing_table: Arc::new(Mutex::new(HashMap::new())),
+        }
+    }
+}
+
+impl Default for PlayerRouter {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+// TODO: implement a way to expire entries
+impl PlayerRouter {
+    fn put(&self, player_key: String, entry: SyncThingData) {
+        let mut routing_table = self.routing_table.lock().unwrap();
+        routing_table.insert(player_key, entry);
+    }
+
+    fn take(&self, player_key: &str) -> Option<SyncThingData> {
+        // TODO: this design does not allow for reconnects. Is this desired?
+        let mut routing_table = self.routing_table.lock().unwrap();
+        routing_table.remove(player_key)
+    }
+}
+
+#[tonic::async_trait]
+impl pb::client_api_service_server::ClientApiService for ClientApiServer {
+    type ConnectPlayerStream = UnboundedReceiverStream<Result<pb::PlayerApiServerMessage, Status>>;
+
+    async fn connect_player(
+        &self,
+        req: Request<Streaming<pb::PlayerApiClientMessage>>,
+    ) -> Result<Response<Self::ConnectPlayerStream>, Status> {
+        // TODO: clean up errors
+        let player_key = req
+            .metadata()
+            .get("player_key")
+            .ok_or_else(|| Status::unauthenticated("no player_key provided"))?;
+
+        let player_key_str = player_key
+            .to_str()
+            .map_err(|_| Status::invalid_argument("unreadable string"))?;
+
+        let sync_data = self
+            .router
+            .take(player_key_str)
+            .ok_or_else(|| Status::not_found("player_key not found"))?;
+
+        let stream = req.into_inner();
+
+        sync_data.tx.send(stream).unwrap();
+        Ok(Response::new(UnboundedReceiverStream::new(
+            sync_data.server_messages,
+        )))
+    }
+
+    async fn create_match(
+        &self,
+        req: Request<pb::CreateMatchRequest>,
+    ) -> Result<Response<pb::CreateMatchResponse>, Status> {
+        // TODO: unify with matchrunner module
+        let conn = self.conn_pool.get().await.unwrap();
+
+        let match_request = req.get_ref();
+
+        let (opponent_bot, opponent_bot_version) =
+            db::bots::find_bot_with_version_by_name(&match_request.opponent_name, &conn)
+                .map_err(|_| Status::not_found("opponent not found"))?;
+
+        let player_key = gen_alphanumeric(32);
+
+        let remote_bot_spec = Box::new(RemoteBotSpec {
+            player_key: player_key.clone(),
+            router: self.router.clone(),
+        });
+        let run_match = RunMatch::from_players(
+            self.runner_config.clone(),
+            vec![
+                MatchPlayer::BotSpec {
+                    spec: remote_bot_spec,
+                },
+                MatchPlayer::BotVersion {
+                    bot: Some(opponent_bot),
+                    version: opponent_bot_version,
+                },
+            ],
+        );
+        let (created_match, _) = run_match
+            .run(self.conn_pool.clone())
+            .await
+            .expect("failed to create match");
+
+        Ok(Response::new(pb::CreateMatchResponse {
+            match_id: created_match.base.id,
+            player_key,
+            // TODO: can we avoid hardcoding this?
+            match_url: format!(
+                "{}/matches/{}",
+                self.runner_config.root_url, created_match.base.id
+            ),
+        }))
+    }
+}
+
+// TODO: please rename me
+struct SyncThingData {
+    tx: oneshot::Sender<Streaming<pb::PlayerApiClientMessage>>,
+    server_messages: mpsc::UnboundedReceiver<Result<pb::PlayerApiServerMessage, Status>>,
+}
+
+struct RemoteBotSpec {
+    player_key: String,
+    router: PlayerRouter,
+}
+
+#[tonic::async_trait]
+impl runner::BotSpec for RemoteBotSpec {
+    async fn run_bot(
+        &self,
+        player_id: u32,
+        event_bus: Arc<Mutex<EventBus>>,
+        _match_logger: MatchLogger,
+    ) -> Box<dyn PlayerHandle> {
+        let (tx, rx) = oneshot::channel();
+        let (server_msg_snd, server_msg_recv) = mpsc::unbounded_channel();
+        self.router.put(
+            self.player_key.clone(),
+            SyncThingData {
+                tx,
+                server_messages: server_msg_recv,
+            },
+        );
+
+        let fut = tokio::time::timeout(Duration::from_secs(10), rx);
+        match fut.await {
+            Ok(Ok(client_messages)) => {
+                // let client_messages = rx.await.unwrap();
+                tokio::spawn(handle_bot_messages(
+                    player_id,
+                    event_bus.clone(),
+                    client_messages,
+                ));
+            }
+            _ => {
+                // ensure router cleanup
+                self.router.take(&self.player_key);
+            }
+        };
+
+        // If the player did not connect, the receiving half of `sender`
+        // will be dropped here, resulting in a time-out for every turn.
+        // This is fine for now, but
+        // TODO: provide a formal mechanism for player startup failure
+        Box::new(RemoteBotHandle {
+            sender: server_msg_snd,
+            player_id,
+            event_bus,
+        })
+    }
+}
+
+async fn handle_bot_messages(
+    player_id: u32,
+    event_bus: Arc<Mutex<EventBus>>,
+    mut messages: Streaming<pb::PlayerApiClientMessage>,
+) {
+    // TODO: can this be writte nmore nicely?
+    while let Some(message) = messages.message().await.unwrap() {
+        match message.client_message {
+            Some(pb::PlayerApiClientMessageType::Action(resp)) => {
+                let request_id = (player_id, resp.action_request_id as u32);
+                event_bus
+                    .lock()
+                    .unwrap()
+                    .resolve_request(request_id, Ok(resp.content));
+            }
+            _ => (),
+        }
+    }
+}
+
+struct RemoteBotHandle {
+    sender: mpsc::UnboundedSender<Result<pb::PlayerApiServerMessage, Status>>,
+    player_id: u32,
+    event_bus: Arc<Mutex<EventBus>>,
+}
+
+impl PlayerHandle for RemoteBotHandle {
+    fn send_request(&mut self, r: RequestMessage) {
+        let req = pb::PlayerActionRequest {
+            action_request_id: r.request_id as i32,
+            content: r.content,
+        };
+
+        let server_message = pb::PlayerApiServerMessage {
+            server_message: Some(pb::PlayerApiServerMessageType::ActionRequest(req)),
+        };
+
+        let res = self.sender.send(Ok(server_message));
+        match res {
+            Ok(()) => {
+                // schedule a timeout. See comments at method implementation
+                tokio::spawn(schedule_timeout(
+                    (self.player_id, r.request_id),
+                    r.timeout,
+                    self.event_bus.clone(),
+                ));
+            }
+            Err(_send_error) => {
+                // cannot contact the remote bot anymore;
+                // directly mark all requests as timed out.
+                // TODO: create a dedicated error type for this.
+                // should it be logged?
+                println!("send error: {:?}", _send_error);
+                self.event_bus
+                    .lock()
+                    .unwrap()
+                    .resolve_request((self.player_id, r.request_id), Err(RequestError::Timeout));
+            }
+        }
+    }
+}
+
+// TODO: this will spawn a task for every request, which might not be ideal.
+// Some alternatives:
+//  - create a single task that manages all time-outs.
+//  - intersperse timeouts with incoming client messages
+//  - push timeouts upwards, into the matchrunner logic (before we hit the playerhandle).
+//    This was initially not done to allow timer start to be delayed until the message actually arrived
+//    with the player. Is this still needed, or is there a different way to do this?
+//
+async fn schedule_timeout(
+    request_id: (u32, u32),
+    duration: Duration,
+    event_bus: Arc<Mutex<EventBus>>,
+) {
+    tokio::time::sleep(duration).await;
+    event_bus
+        .lock()
+        .unwrap()
+        .resolve_request(request_id, Err(RequestError::Timeout));
+}
+
+pub async fn run_client_api(runner_config: Arc<GlobalConfig>, pool: ConnectionPool) {
+    let router = PlayerRouter::new();
+    let server = ClientApiServer {
+        router,
+        conn_pool: pool,
+        runner_config,
+    };
+
+    let addr = SocketAddr::from(([127, 0, 0, 1], 50051));
+    Server::builder()
+        .add_service(pb::client_api_service_server::ClientApiServiceServer::new(
+            server,
+        ))
+        .serve(addr)
+        .await
+        .unwrap()
+}