synchronize both player sockets on game start

game.go

@@ -58,6 +58,10 @@ func gameActor(ctx context.Context, g *game.Match, dealer, chall person, join <-
 	// definitely expired.
 	ctx, stop := context.WithTimeoutCause(ctx, 4*time.Hour, errMatchExpired)
 	defer stop()
+	// Accept joins from the dealer and challenger. We don't care which is
+	// which, but we need to get both to synchronize the socket.
+	<-join
+	<-join
 	var obs []observer
 	actions := make(chan action, 2)
 	go playerActor(ctx, dealer, actions)

main.go

@@ -46,6 +46,7 @@ func main() {
 		creds:    db,
 		sessions: db,
 		pp:       map[player.ID]*websocket.Conn{},
+		j:        map[lobby.GameID]chan person{},
 	}
 
 	r := chi.NewRouter()

server.go

@@ -26,6 +26,7 @@ type Server struct {
 
 	mu sync.Mutex
 	pp map[player.ID]*websocket.Conn
+	j  map[lobby.GameID]chan person
 }
 
 type db interface {
@@ -214,10 +215,25 @@ func (s *Server) joinAndServe(p person) {
 		return
 	}
 	if deal {
+		ch := make(chan person, 2)
+		s.mu.Lock()
+		s.j[id] = ch
+		s.mu.Unlock()
 		g := game.New(p.id, chall)
 		other := s.person(chall)
-		// TODO(zeph): save the game state s.t. we can provide a join channel
-		go gameActor(context.TODO(), g, p, other, nil)
+		go gameActor(context.TODO(), g, p, other, ch)
+		ch <- p
+	} else {
+		// very gross, but i just want this to exist
+		for {
+			s.mu.Lock()
+			ch := s.j[id]
+			s.mu.Unlock()
+			if ch != nil {
+				ch <- p
+				break
+			}
+		}
 	}
 	// Reply with the game ID so they can share.
 	r := serve.GameStart{