feat(lobby): enter the game immediately and wait for the opponent inside it

Quick auto-match no longer waits on a separate screen: Enqueue opens a real game seating the caller with an empty opponent seat (new game status 'open') and the player enters it at once. A second human searching the same variant+rule joins that open game; otherwise a background reaper seats a robot after a 90s + random 0-90s wait, pushing a new in-app opponent_joined event that fills the opponent card and re-enables resign and chat in place.

Matchmaking state is now the open games in the database (the in-memory pool, lobby.poll and lobby.cancel are gone), serialised by a per-bucket advisory lock. While a game is open the starter may move on their turn, but resign, chat and nudge are refused; the lobby and opponent card show "searching for opponent".

Schema edited in the baseline (no prod data): 'open' status, nullable game_players.account_id for the empty seat, and a games.open_deadline_at stamp; jet code regenerated.

backend/internal/inttest/helpers.go

@@ -56,11 +56,21 @@ func newRobotService(t *testing.T, games *game.Service) *robot.Service {
 	return robot.NewService(games, account.NewStore(testDB), newSocialService(), noop.NewMeterProvider().Meter("robot-test"), zap.NewNop())
 }
 
-// newMatchmaker builds a matchmaker starting real games and substituting from
-// robots after wait.
-func newMatchmaker(t *testing.T, robots lobby.RobotProvider, wait time.Duration) *lobby.Matchmaker {
+// newMatchmaker builds a matchmaker opening real games and substituting from robots
+// after minWait plus a random jitter in [0, jitter).
+func newMatchmaker(t *testing.T, robots lobby.RobotProvider, minWait, jitter time.Duration) *lobby.Matchmaker {
 	t.Helper()
-	return lobby.NewMatchmaker(newGameService(), robots, wait, zap.NewNop())
+	return lobby.NewMatchmaker(newGameService(), robots, minWait, jitter, zap.NewNop())
+}
+
+// clearOpenGames deletes every open (awaiting-opponent) game so a matchmaking test
+// starts from a clean slate: the shared test database is FIFO-joined across tests, so a
+// leftover open game would otherwise be joined (or opened-into) instead of a fresh one.
+func clearOpenGames(t *testing.T) {
+	t.Helper()
+	if _, err := testDB.ExecContext(context.Background(), `DELETE FROM backend.games WHERE status = 'open'`); err != nil {
+		t.Fatalf("clear open games: %v", err)
+	}
 }
 
 // provisionAccount creates a fresh durable account and returns its id.

backend/internal/inttest/lobby_test.go

@@ -30,31 +30,67 @@ func englishInvite() lobby.InvitationSettings {
 	}
 }
 
-func TestMatchmakingPairsAndStartsGame(t *testing.T) {
+func TestMatchmakingOpensThenJoins(t *testing.T) {
 	ctx := context.Background()
-	mm := newMatchmaker(t, newRobotService(t, newGameService()), 10*time.Second)
+	clearOpenGames(t)
+	mm := newMatchmaker(t, newRobotService(t, newGameService()), 90*time.Second, 90*time.Second)
 	a, b := provisionAccount(t), provisionAccount(t)
 
+	// The first player opens a game and enters it immediately, still awaiting an opponent.
 	r1, err := mm.Enqueue(ctx, a, engine.VariantEnglish, true)
 	if err != nil {
 		t.Fatalf("enqueue a: %v", err)
 	}
 	if r1.Matched {
-		t.Fatal("first enqueue must wait")
+		t.Fatal("first enqueue must open a game awaiting an opponent, not match")
 	}
+	if _, _, status, err := newGameService().Participants(ctx, r1.Game.ID); err != nil || status != "open" {
+		t.Fatalf("opened game status = %q err %v, want open", status, err)
+	}
+
+	// A second player for the same variant and rule joins that open game, which starts.
 	r2, err := mm.Enqueue(ctx, b, engine.VariantEnglish, true)
 	if err != nil {
 		t.Fatalf("enqueue b: %v", err)
 	}
-	if !r2.Matched {
-		t.Fatal("second enqueue must match")
+	if !r2.Matched || r2.Game.ID != r1.Game.ID {
+		t.Fatalf("second enqueue = (matched %v, game %s), want it to join the open game %s", r2.Matched, r2.Game.ID, r1.Game.ID)
 	}
 	seats, _, status, err := newGameService().Participants(ctx, r2.Game.ID)
 	if err != nil {
 		t.Fatalf("participants: %v", err)
 	}
-	if status != "active" || len(seats) != 2 {
-		t.Fatalf("matched game state: status %q seats %v", status, seats)
+	has := func(id uuid.UUID) bool {
+		for _, s := range seats {
+			if s == id {
+				return true
+			}
+		}
+		return false
+	}
+	if status != "active" || len(seats) != 2 || !has(a) || !has(b) {
+		t.Fatalf("joined game: status %q seats %v (want active with a=%s and b=%s)", status, seats, a, b)
+	}
+}
+
+// TestMatchmakingReEnqueueReturnsOwnOpenGame checks a re-enqueue is idempotent: the
+// caller gets their existing open game rather than a second one.
+func TestMatchmakingReEnqueueReturnsOwnOpenGame(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	mm := newMatchmaker(t, newRobotService(t, newGameService()), 90*time.Second, 90*time.Second)
+	a := provisionAccount(t)
+
+	r1, err := mm.Enqueue(ctx, a, engine.VariantEnglish, true)
+	if err != nil {
+		t.Fatalf("enqueue: %v", err)
+	}
+	r2, err := mm.Enqueue(ctx, a, engine.VariantEnglish, true)
+	if err != nil {
+		t.Fatalf("re-enqueue: %v", err)
+	}
+	if r2.Game.ID != r1.Game.ID || r2.Matched {
+		t.Fatalf("re-enqueue = (game %s, matched %v), want the same open game %s unmatched", r2.Game.ID, r2.Matched, r1.Game.ID)
 	}
 }
 

backend/internal/inttest/open_match_test.go

@@ -0,0 +1,254 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
+	"scrabble/backend/internal/social"
+)
+
+// The open-game suite covers an auto-match game that a player enters immediately and
+// waits inside (status 'open', the opponent seat empty) until a human or a robot joins.
+
+// evenOpeningSeed returns an even seed (so OpenOrJoin seats the starter at seat 0, which
+// moves first) whose fresh two-player English opening rack has a legal move.
+func evenOpeningSeed(t *testing.T) int64 {
+	t.Helper()
+	for seed := int64(2); seed <= 400; seed += 2 {
+		g, err := engine.New(testRegistry, engine.Options{Variant: engine.VariantEnglish, Version: testDictVersion, Players: 2, Seed: seed})
+		if err != nil {
+			t.Fatalf("engine new: %v", err)
+		}
+		if _, ok := g.HintView(); ok {
+			return seed
+		}
+	}
+	t.Fatal("no even opening seed found")
+	return 0
+}
+
+// openParams are the casual auto-match settings with a pinned seed.
+func openParams(seed int64) game.CreateParams {
+	return game.CreateParams{
+		Variant:              engine.VariantEnglish,
+		TurnTimeout:          24 * time.Hour,
+		HintsAllowed:         true,
+		HintsPerPlayer:       1,
+		MultipleWordsPerTurn: true,
+		Seed:                 seed,
+	}
+}
+
+func openGame(t *testing.T, svc *game.Service, starter uuid.UUID, seed int64) game.Game {
+	t.Helper()
+	g, joined, err := svc.OpenOrJoin(context.Background(), starter, openParams(seed), time.Now().Add(time.Minute))
+	if err != nil {
+		t.Fatalf("open game: %v", err)
+	}
+	if joined || g.Status != game.StatusOpen {
+		t.Fatalf("opened game = (joined %v, status %q), want (false, open)", joined, g.Status)
+	}
+	return g
+}
+
+// TestOpenGameStarterMovesThenWaits checks the starter (seat 0) may move on their turn
+// while the game is open, after which it is the empty opponent seat's turn and the
+// starter just waits.
+func TestOpenGameStarterMovesThenWaits(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	seed := evenOpeningSeed(t)
+	g := openGame(t, svc, provisionAccount(t), seed)
+	starter := g.Seats[0].AccountID
+
+	hint, ok := newMirror(t, seed, 2).HintView()
+	if !ok || len(hint.Tiles) == 0 {
+		t.Fatal("no opening move for the seed")
+	}
+	res, err := svc.SubmitPlay(ctx, g.ID, starter, hint.Tiles)
+	if err != nil {
+		t.Fatalf("starter play while open: %v", err)
+	}
+	if res.Game.Status != game.StatusOpen {
+		t.Errorf("after the starter's move the game must stay open, got %q", res.Game.Status)
+	}
+	if res.Game.ToMove != 1 {
+		t.Errorf("after the starter's move it must be the empty seat's turn (to_move 1), got %d", res.Game.ToMove)
+	}
+	if _, err := svc.Pass(ctx, g.ID, starter); !errors.Is(err, game.ErrNotYourTurn) {
+		t.Fatalf("starter acting on the opponent's turn = %v, want ErrNotYourTurn", err)
+	}
+}
+
+// TestOpenGameStarterWaitsWhenOpponentMovesFirst checks that when the starter is seated
+// at seat 1 (odd seed), the still-empty seat 0 is to move, so the starter cannot act.
+func TestOpenGameStarterWaitsWhenOpponentMovesFirst(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	starter := provisionAccount(t)
+	g, _, err := svc.OpenOrJoin(ctx, starter, openParams(1), time.Now().Add(time.Minute))
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	if g.ToMove != 0 || g.Seats[0].AccountID != uuid.Nil {
+		t.Fatalf("odd-seed open game: to_move %d seat0 %s, want the empty seat 0 to move", g.ToMove, g.Seats[0].AccountID)
+	}
+	if _, err := svc.Pass(ctx, g.ID, starter); !errors.Is(err, game.ErrNotYourTurn) {
+		t.Fatalf("starter acting on the empty seat's turn = %v, want ErrNotYourTurn", err)
+	}
+}
+
+// TestOpenGameJoinAfterStarterMoved checks a second human joins an open game even after
+// the starter has already made their first move, landing on the board mid-opening and
+// able to act on their turn.
+func TestOpenGameJoinAfterStarterMoved(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	seed := evenOpeningSeed(t)
+	g := openGame(t, svc, provisionAccount(t), seed)
+	starter := g.Seats[0].AccountID
+
+	hint, ok := newMirror(t, seed, 2).HintView()
+	if !ok {
+		t.Fatal("no opening move")
+	}
+	if _, err := svc.SubmitPlay(ctx, g.ID, starter, hint.Tiles); err != nil {
+		t.Fatalf("starter play: %v", err)
+	}
+
+	joiner := provisionAccount(t)
+	g2, joined, err := svc.OpenOrJoin(ctx, joiner, openParams(0), time.Now().Add(time.Minute))
+	if err != nil {
+		t.Fatalf("join: %v", err)
+	}
+	if !joined || g2.ID != g.ID {
+		t.Fatalf("join = (joined %v, game %s), want it to join %s", joined, g2.ID, g.ID)
+	}
+	if g2.Status != game.StatusActive || g2.MoveCount != 1 || g2.ToMove != 1 {
+		t.Fatalf("joined game = (status %q, moves %d, to_move %d), want (active, 1, 1)", g2.Status, g2.MoveCount, g2.ToMove)
+	}
+	// It is the joiner's turn (seat 1); they can act.
+	if _, err := svc.Pass(ctx, g.ID, joiner); err != nil {
+		t.Fatalf("joiner pass on their turn: %v", err)
+	}
+}
+
+// TestOpenGameResignRejectedUntilOpponent checks resign is refused while the game is
+// open and allowed once an opponent (a robot here) has joined.
+func TestOpenGameResignRejectedUntilOpponent(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	robots := newRobotService(t, svc)
+	if err := robots.EnsurePool(ctx); err != nil {
+		t.Fatalf("ensure pool: %v", err)
+	}
+	g := openGame(t, svc, provisionAccount(t), evenOpeningSeed(t))
+	starter := g.Seats[0].AccountID
+
+	if _, err := svc.Resign(ctx, g.ID, starter); !errors.Is(err, game.ErrNoOpponentYet) {
+		t.Fatalf("resign while open = %v, want ErrNoOpponentYet", err)
+	}
+
+	robotID, err := robots.Pick(engine.VariantEnglish)
+	if err != nil {
+		t.Fatalf("pick: %v", err)
+	}
+	if _, attached, err := svc.AttachRobot(ctx, g.ID, robotID); err != nil || !attached {
+		t.Fatalf("attach robot = (attached %v, err %v), want attached", attached, err)
+	}
+	res, err := svc.Resign(ctx, g.ID, starter)
+	if err != nil {
+		t.Fatalf("resign after the opponent joined: %v", err)
+	}
+	if res.Game.Status != game.StatusFinished {
+		t.Errorf("resign must finish the game, got %q", res.Game.Status)
+	}
+}
+
+// TestOpenGameChatAndNudgeRejected checks chat and nudge are refused while the game is
+// open (no opponent to converse with).
+func TestOpenGameChatAndNudgeRejected(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	soc := newSocialService()
+	g := openGame(t, svc, provisionAccount(t), evenOpeningSeed(t))
+	starter := g.Seats[0].AccountID
+
+	if _, err := soc.PostMessage(ctx, g.ID, starter, "hello", ""); !errors.Is(err, social.ErrGameNotActive) {
+		t.Errorf("chat while open = %v, want ErrGameNotActive", err)
+	}
+	if _, err := soc.Nudge(ctx, g.ID, starter); !errors.Is(err, social.ErrGameNotActive) {
+		t.Errorf("nudge while open = %v, want ErrGameNotActive", err)
+	}
+}
+
+// TestOpenGameSweeperSkips checks the turn-timeout sweeper never finishes an open game,
+// even with a long-stale turn clock (its seat is the empty opponent's).
+func TestOpenGameSweeperSkips(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	g := openGame(t, svc, provisionAccount(t), evenOpeningSeed(t))
+
+	setTurnStarted(t, g.ID, time.Now().Add(-1000*time.Hour))
+	if _, err := svc.SweepTimeouts(ctx, time.Now()); err != nil {
+		t.Fatalf("sweep: %v", err)
+	}
+	g2, err := svc.GameByID(ctx, g.ID)
+	if err != nil {
+		t.Fatalf("get game: %v", err)
+	}
+	if g2.Status != game.StatusOpen {
+		t.Errorf("open game must survive the sweeper, got %q", g2.Status)
+	}
+}
+
+// TestOpenGameLobbyShowsEmptySeat checks an open game appears in the starter's lobby
+// with two seats, one of them the still-empty opponent (uuid.Nil).
+func TestOpenGameLobbyShowsEmptySeat(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	starter := provisionAccount(t)
+	g := openGame(t, svc, starter, evenOpeningSeed(t))
+
+	games, err := svc.ListForAccount(ctx, starter)
+	if err != nil {
+		t.Fatalf("list for account: %v", err)
+	}
+	var found *game.Game
+	for i := range games {
+		if games[i].ID == g.ID {
+			found = &games[i]
+			break
+		}
+	}
+	if found == nil {
+		t.Fatal("open game must appear in the starter's lobby")
+	}
+	var hasStarter, hasEmpty bool
+	for _, s := range found.Seats {
+		switch s.AccountID {
+		case starter:
+			hasStarter = true
+		case uuid.Nil:
+			hasEmpty = true
+		}
+	}
+	if len(found.Seats) != 2 || !hasStarter || !hasEmpty {
+		t.Errorf("open game seats = %+v, want the starter and one empty (nil) seat", found.Seats)
+	}
+}

backend/internal/inttest/robot_test.go

@@ -138,36 +138,29 @@ func TestRobotPlaysAutoMatchToEnd(t *testing.T) {
 	}
 }
 
-// TestMatchmakerSubstitutesRobotEndToEnd checks a waiting human is paired with a
-// real robot account after the wait window, discoverable through Poll.
+// TestMatchmakerSubstitutesRobotEndToEnd checks the reaper fills an open game's empty
+// seat with a real robot account once its wait window has elapsed.
 func TestMatchmakerSubstitutesRobotEndToEnd(t *testing.T) {
 	ctx := context.Background()
+	clearOpenGames(t)
 	robots := newRobotService(t, newGameService())
 	if err := robots.EnsurePool(ctx); err != nil {
 		t.Fatalf("ensure pool: %v", err)
 	}
-	mm := newMatchmaker(t, robots, 10*time.Second)
+	// Zero wait and jitter so the opened game is immediately due for a robot.
+	mm := newMatchmaker(t, robots, 0, 0)
 	human := provisionAccount(t)
 
-	before := time.Now()
 	r, err := mm.Enqueue(ctx, human, engine.VariantEnglish, true)
 	if err != nil {
 		t.Fatalf("enqueue: %v", err)
 	}
 	if r.Matched {
-		t.Fatal("first enqueue must wait")
+		t.Fatal("first enqueue must open a game awaiting an opponent")
 	}
 
-	mm.Reap(ctx, before.Add(11*time.Second))
-	got, err := mm.Poll(ctx, human)
-	if err != nil {
-		t.Fatalf("poll: %v", err)
-	}
-	if !got.Matched {
-		t.Fatal("expected a substituted game after the wait window")
-	}
-
-	seats, _, status, err := newGameService().Participants(ctx, got.Game.ID)
+	mm.Reap(ctx, time.Now().Add(time.Second)) // past the (zero) wait window
+	seats, _, status, err := newGameService().Participants(ctx, r.Game.ID)
 	if err != nil {
 		t.Fatalf("participants: %v", err)
 	}