refactor: extract GameService for Connect 4 NATS/chat handling

Move NATS subscription and chat room management into a dedicated
GameService, following the portigo service pattern. Handlers now
receive the service and call its methods instead of managing
NATS connections directly.

features/c4game/handlers.go

@@ -1,46 +1,23 @@
 package c4game
 
 import (
-	"fmt"
 	"net/http"
 	"strconv"
 	"time"
 
 	"github.com/alexedwards/scs/v2"
 	"github.com/go-chi/chi/v5"
-	"github.com/nats-io/nats.go"
 	"github.com/starfederation/datastar-go/datastar"
 
 	"github.com/ryanhamamura/games/chat"
 	chatcomponents "github.com/ryanhamamura/games/chat/components"
 	"github.com/ryanhamamura/games/connect4"
-	"github.com/ryanhamamura/games/db/repository"
 	"github.com/ryanhamamura/games/features/c4game/pages"
+	"github.com/ryanhamamura/games/features/c4game/services"
 	"github.com/ryanhamamura/games/sessions"
 )
 
-// c4ChatColors maps player color (1=Red, 2=Yellow) to CSS background colors.
-var c4ChatColors = map[int]string{
-	0: "#4a2a3a", // color 1 stored as slot 0
-	1: "#2a4545", // color 2 stored as slot 1
-}
-
-func c4ChatColor(slot int) string {
-	if c, ok := c4ChatColors[slot]; ok {
-		return c
-	}
-	return "#666"
-}
-
-func c4ChatConfig(gameID string) chatcomponents.Config {
-	return chatcomponents.Config{
-		CSSPrefix: "c4",
-		PostURL:   fmt.Sprintf("/games/%s/chat", gameID),
-		Color:     c4ChatColor,
-	}
-}
-
-func HandleGamePage(store *connect4.Store, sm *scs.SessionManager, queries *repository.Queries) http.HandlerFunc {
+func HandleGamePage(store *connect4.Store, svc *services.GameService, sm *scs.SessionManager) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		gameID := chi.URLParam(r, "id")
 
@@ -84,15 +61,15 @@ func HandleGamePage(store *connect4.Store, sm *scs.SessionManager, queries *repo
 		}
 
 		g := gi.GetGame()
-		room := chat.NewPersistentRoom(nil, "", queries, gameID)
+		room := svc.ChatRoom(gameID)
 
-		if err := pages.GamePage(g, myColor, room.Messages(), c4ChatConfig(gameID)).Render(r.Context(), w); err != nil {
+		if err := pages.GamePage(g, myColor, room.Messages(), svc.ChatConfig(gameID)).Render(r.Context(), w); err != nil {
 			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 		}
 	}
 }
 
-func HandleGameEvents(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManager, queries *repository.Queries) http.HandlerFunc {
+func HandleGameEvents(store *connect4.Store, svc *services.GameService, sm *scs.SessionManager) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		ctx := r.Context()
 		gameID := chi.URLParam(r, "id")
@@ -106,8 +83,7 @@ func HandleGameEvents(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManag
 		playerID := sessions.GetPlayerID(sm, r)
 
 		// Subscribe to game state updates BEFORE creating SSE
-		gameCh := make(chan *nats.Msg, 64)
-		gameSub, err := nc.ChanSubscribe(connect4.GameSubject(gameID), gameCh)
+		gameSub, gameCh, err := svc.SubscribeGameUpdates(gameID)
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 			return
@@ -115,8 +91,8 @@ func HandleGameEvents(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManag
 		defer gameSub.Unsubscribe() //nolint:errcheck
 
 		// Subscribe to chat messages BEFORE creating SSE
-		chatCfg := c4ChatConfig(gameID)
-		room := chat.NewPersistentRoom(nc, connect4.ChatSubject(gameID), queries, gameID)
+		chatCfg := svc.ChatConfig(gameID)
+		room := svc.ChatRoom(gameID)
 		chatCh, cleanupChat := room.Subscribe()
 		defer cleanupChat()
 
@@ -209,7 +185,7 @@ func HandleDropPiece(store *connect4.Store, sm *scs.SessionManager) http.Handler
 	}
 }
 
-func HandleSendChat(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManager, queries *repository.Queries) http.HandlerFunc {
+func HandleSendChat(store *connect4.Store, svc *services.GameService, sm *scs.SessionManager) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		gameID := chi.URLParam(r, "id")
 
@@ -256,7 +232,7 @@ func HandleSendChat(store *connect4.Store, nc *nats.Conn, sm *scs.SessionManager
 			Message:  signals.ChatMsg,
 			Time:     time.Now().UnixMilli(),
 		}
-		room := chat.NewPersistentRoom(nc, connect4.ChatSubject(gameID), queries, gameID)
+		room := svc.ChatRoom(gameID)
 		room.Send(msg)
 
 		sse := datastar.NewSSE(w, r)

features/c4game/routes.go

@@ -4,24 +4,22 @@ package c4game
 import (
 	"github.com/alexedwards/scs/v2"
 	"github.com/go-chi/chi/v5"
-	"github.com/nats-io/nats.go"
 
 	"github.com/ryanhamamura/games/connect4"
-	"github.com/ryanhamamura/games/db/repository"
+	"github.com/ryanhamamura/games/features/c4game/services"
 )
 
 func SetupRoutes(
 	router chi.Router,
 	store *connect4.Store,
-	nc *nats.Conn,
+	svc *services.GameService,
 	sessions *scs.SessionManager,
-	queries *repository.Queries,
 ) {
 	router.Route("/games/{id}", func(r chi.Router) {
-		r.Get("/", HandleGamePage(store, sessions, queries))
-		r.Get("/events", HandleGameEvents(store, nc, sessions, queries))
+		r.Get("/", HandleGamePage(store, svc, sessions))
+		r.Get("/events", HandleGameEvents(store, svc, sessions))
 		r.Post("/drop", HandleDropPiece(store, sessions))
-		r.Post("/chat", HandleSendChat(store, nc, sessions, queries))
+		r.Post("/chat", HandleSendChat(store, svc, sessions))
 		r.Post("/join", HandleSetNickname(store, sessions))
 		r.Post("/rematch", HandleRematch(store, sessions))
 	})

features/c4game/services/game_service.go

@@ -0,0 +1,70 @@
+// Package services provides the game service layer for Connect 4,
+// handling NATS subscriptions and chat room management.
+package services
+
+import (
+	"fmt"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/ryanhamamura/games/chat"
+	chatcomponents "github.com/ryanhamamura/games/chat/components"
+	"github.com/ryanhamamura/games/connect4"
+	"github.com/ryanhamamura/games/db/repository"
+)
+
+// c4ChatColors maps player slot (0-indexed) to CSS background colors.
+var c4ChatColors = map[int]string{
+	0: "#4a2a3a", // Red player
+	1: "#2a4545", // Yellow player
+}
+
+func c4ChatColor(slot int) string {
+	if c, ok := c4ChatColors[slot]; ok {
+		return c
+	}
+	return "#666"
+}
+
+// GameService manages NATS subscriptions and chat for Connect 4 games.
+type GameService struct {
+	nc      *nats.Conn
+	queries *repository.Queries
+}
+
+// NewGameService creates a new game service.
+func NewGameService(nc *nats.Conn, queries *repository.Queries) *GameService {
+	return &GameService{
+		nc:      nc,
+		queries: queries,
+	}
+}
+
+// SubscribeGameUpdates returns a NATS subscription and channel for game state updates.
+func (s *GameService) SubscribeGameUpdates(gameID string) (*nats.Subscription, <-chan *nats.Msg, error) {
+	ch := make(chan *nats.Msg, 64)
+	sub, err := s.nc.ChanSubscribe(connect4.GameSubject(gameID), ch)
+	if err != nil {
+		return nil, nil, fmt.Errorf("subscribing to game updates: %w", err)
+	}
+	return sub, ch, nil
+}
+
+// ChatConfig returns the chat configuration for a game.
+func (s *GameService) ChatConfig(gameID string) chatcomponents.Config {
+	return chatcomponents.Config{
+		CSSPrefix: "c4",
+		PostURL:   fmt.Sprintf("/games/%s/chat", gameID),
+		Color:     c4ChatColor,
+	}
+}
+
+// ChatRoom returns a persistent chat room for a game.
+func (s *GameService) ChatRoom(gameID string) *chat.Room {
+	return chat.NewPersistentRoom(s.nc, connect4.ChatSubject(gameID), s.queries, gameID)
+}
+
+// PublishGameUpdate sends a notification that the game state has changed.
+func (s *GameService) PublishGameUpdate(gameID string) error {
+	return s.nc.Publish(connect4.GameSubject(gameID), nil)
+}