From d0faec7d1f4deb132554db7f946df4b9d4e9711b Mon Sep 17 00:00:00 2001
From: Ilion Beyst <ilion.beyst@gmail.com>
Date: Mon, 6 Jun 2022 13:08:43 +0200
Subject: [PATCH] implement PlayerRouter

---
 planetwars-server/src/modules/bot_api.rs | 71 +++++++++++++++---------
 1 file changed, 45 insertions(+), 26 deletions(-)

diff --git a/planetwars-server/src/modules/bot_api.rs b/planetwars-server/src/modules/bot_api.rs
index 0f1ff82..2face62 100644
--- a/planetwars-server/src/modules/bot_api.rs
+++ b/planetwars-server/src/modules/bot_api.rs
@@ -2,8 +2,8 @@ pub mod pb {
     tonic::include_proto!("grpc.planetwars.bot_api");
 }
 
+use std::collections::HashMap;
 use std::net::SocketAddr;
-use std::ops::DerefMut;
 use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 
@@ -23,7 +23,35 @@ use crate::{ConnectionPool, MAPS_DIR, MATCHES_DIR};
 use super::matches::code_bundle_to_botspec;
 
 pub struct BotApiServer {
-    sync_thing: ServerSyncThing,
+    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())),
+        }
+    }
+}
+
+// TODO: implement a way to expire entries
+impl PlayerRouter {
+    fn put(&self, player_id: String, entry: SyncThingData) {
+        let mut routing_table = self.routing_table.lock().unwrap();
+        routing_table.insert(player_id, entry);
+    }
+
+    fn get(&self, player_id: &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_id)
+    }
 }
 
 #[tonic::async_trait]
@@ -36,7 +64,8 @@ impl pb::bot_api_service_server::BotApiService for BotApiServer {
     ) -> Result<Response<Self::ConnectBotStream>, Status> {
         println!("bot connected");
         let stream = req.into_inner();
-        let sync_data = self.sync_thing.streams.lock().unwrap().take().unwrap();
+        // TODO: return error when player does not exist
+        let sync_data = self.router.get("test_player").unwrap();
         sync_data.tx.send(stream).unwrap();
         Ok(Response::new(UnboundedReceiverStream::new(
             sync_data.server_messages,
@@ -44,26 +73,13 @@ impl pb::bot_api_service_server::BotApiService for BotApiServer {
     }
 }
 
-#[derive(Clone)]
-struct ServerSyncThing {
-    streams: Arc<Mutex<Option<SyncThingData>>>,
-}
-
 struct SyncThingData {
     tx: oneshot::Sender<Streaming<pb::PlayerRequestResponse>>,
     server_messages: mpsc::UnboundedReceiver<Result<pb::PlayerRequest, Status>>,
 }
 
-impl ServerSyncThing {
-    fn new() -> Self {
-        ServerSyncThing {
-            streams: Arc::new(Mutex::new(None)),
-        }
-    }
-}
-
 struct RemoteBotSpec {
-    sync_thing: ServerSyncThing,
+    router: PlayerRouter,
 }
 
 #[tonic::async_trait]
@@ -76,10 +92,13 @@ impl runner::BotSpec for RemoteBotSpec {
     ) -> Box<dyn PlayerHandle> {
         let (tx, rx) = oneshot::channel();
         let (server_msg_snd, server_msg_recv) = mpsc::unbounded_channel();
-        *self.sync_thing.streams.lock().unwrap().deref_mut() = Some(SyncThingData {
-            tx,
-            server_messages: server_msg_recv,
-        });
+        self.router.put(
+            "test_player".to_string(),
+            SyncThingData {
+                tx,
+                server_messages: server_msg_recv,
+            },
+        );
 
         let client_messages = rx.await.unwrap();
         tokio::spawn(handle_bot_messages(player_id, event_bus, client_messages));
@@ -119,7 +138,7 @@ impl PlayerHandle for RemoteBotHandle {
     }
 }
 
-async fn run_match(sync_thing: ServerSyncThing, pool: ConnectionPool) {
+async fn run_match(router: PlayerRouter, pool: ConnectionPool) {
     let conn = pool.get().await.unwrap();
 
     let opponent = db::bots::find_bot_by_name("simplebot", &conn).unwrap();
@@ -127,7 +146,7 @@ async fn run_match(sync_thing: ServerSyncThing, pool: ConnectionPool) {
 
     let log_file_name = "remote_match.log";
 
-    let remote_bot_spec = RemoteBotSpec { sync_thing };
+    let remote_bot_spec = RemoteBotSpec { router };
 
     let match_config = runner::MatchConfig {
         map_path: PathBuf::from(MAPS_DIR).join("hex.json"),
@@ -147,9 +166,9 @@ async fn run_match(sync_thing: ServerSyncThing, pool: ConnectionPool) {
 }
 
 pub async fn run_bot_api(pool: ConnectionPool) {
-    let sync_thing = ServerSyncThing::new();
-    tokio::spawn(run_match(sync_thing.clone(), pool));
-    let server = BotApiServer { sync_thing };
+    let router = PlayerRouter::new();
+    tokio::spawn(run_match(router.clone(), pool));
+    let server = BotApiServer { router };
 
     let addr = SocketAddr::from(([127, 0, 0, 1], 50051));
     Server::builder()