refactor: remove persister abstraction layer

Inline persistence logic directly into game stores and handlers:
- game/persist.go: DB mapping methods on GameStore and GameInstance
- snake/persist.go: DB mapping methods on SnakeStore and SnakeGameInstance
- Chat persistence inlined into c4game handlers
- Delete db/persister.go (GamePersister, SnakePersister, ChatPersister)
- Stores now take *repository.Queries directly instead of Persister interface

game/persist.go

@@ -0,0 +1,157 @@
+package game
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/ryanhamamura/c4/db/repository"
+)
+
+// Persistence methods on GameStore (used during Get to hydrate from DB).
+
+func (gs *GameStore) saveGame(g *Game) error {
+	ctx := context.Background()
+
+	_, err := gs.queries.GetGame(ctx, g.ID)
+	if err == sql.ErrNoRows {
+		_, err = gs.queries.CreateGame(ctx, repository.CreateGameParams{
+			ID:          g.ID,
+			Board:       g.BoardToJSON(),
+			CurrentTurn: int64(g.CurrentTurn),
+			Status:      int64(g.Status),
+		})
+		return err
+	}
+	if err != nil {
+		return err
+	}
+
+	return gs.queries.UpdateGame(ctx, updateGameParams(g))
+}
+
+func (gs *GameStore) loadGame(id string) (*Game, error) {
+	row, err := gs.queries.GetGame(context.Background(), id)
+	if err != nil {
+		return nil, err
+	}
+	return gameFromRow(row)
+}
+
+func (gs *GameStore) loadGamePlayers(id string) ([]*Player, error) {
+	rows, err := gs.queries.GetGamePlayers(context.Background(), id)
+	if err != nil {
+		return nil, err
+	}
+	return playersFromRows(rows), nil
+}
+
+// Persistence methods on GameInstance (used during gameplay mutations).
+
+func (gi *GameInstance) saveGame(g *Game) error {
+	ctx := context.Background()
+
+	_, err := gi.queries.GetGame(ctx, g.ID)
+	if err == sql.ErrNoRows {
+		_, err = gi.queries.CreateGame(ctx, repository.CreateGameParams{
+			ID:          g.ID,
+			Board:       g.BoardToJSON(),
+			CurrentTurn: int64(g.CurrentTurn),
+			Status:      int64(g.Status),
+		})
+		return err
+	}
+	if err != nil {
+		return err
+	}
+
+	return gi.queries.UpdateGame(ctx, updateGameParams(g))
+}
+
+func (gi *GameInstance) saveGamePlayer(gameID string, player *Player, slot int) error {
+	var userID, guestPlayerID sql.NullString
+	if player.UserID != nil {
+		userID = sql.NullString{String: *player.UserID, Valid: true}
+	} else {
+		guestPlayerID = sql.NullString{String: string(player.ID), Valid: true}
+	}
+
+	return gi.queries.CreateGamePlayer(context.Background(), repository.CreateGamePlayerParams{
+		GameID:        gameID,
+		UserID:        userID,
+		GuestPlayerID: guestPlayerID,
+		Nickname:      player.Nickname,
+		Color:         int64(player.Color),
+		Slot:          int64(slot),
+	})
+}
+
+// Shared helpers for domain ↔ DB mapping.
+
+func updateGameParams(g *Game) repository.UpdateGameParams {
+	var winnerUserID sql.NullString
+	if g.Winner != nil && g.Winner.UserID != nil {
+		winnerUserID = sql.NullString{String: *g.Winner.UserID, Valid: true}
+	}
+
+	var winningCells sql.NullString
+	if wc := g.WinningCellsToJSON(); wc != "" {
+		winningCells = sql.NullString{String: wc, Valid: true}
+	}
+
+	var rematchGameID sql.NullString
+	if g.RematchGameID != nil {
+		rematchGameID = sql.NullString{String: *g.RematchGameID, Valid: true}
+	}
+
+	return repository.UpdateGameParams{
+		Board:         g.BoardToJSON(),
+		CurrentTurn:   int64(g.CurrentTurn),
+		Status:        int64(g.Status),
+		WinnerUserID:  winnerUserID,
+		WinningCells:  winningCells,
+		RematchGameID: rematchGameID,
+		ID:            g.ID,
+	}
+}
+
+func gameFromRow(row repository.Game) (*Game, error) {
+	g := &Game{
+		ID:          row.ID,
+		CurrentTurn: int(row.CurrentTurn),
+		Status:      GameStatus(row.Status),
+	}
+
+	if err := g.BoardFromJSON(row.Board); err != nil {
+		return nil, err
+	}
+
+	if row.WinningCells.Valid {
+		g.WinningCellsFromJSON(row.WinningCells.String)
+	}
+
+	if row.RematchGameID.Valid {
+		g.RematchGameID = &row.RematchGameID.String
+	}
+
+	return g, nil
+}
+
+func playersFromRows(rows []repository.GamePlayer) []*Player {
+	players := make([]*Player, 0, len(rows))
+	for _, row := range rows {
+		player := &Player{
+			Nickname: row.Nickname,
+			Color:    int(row.Color),
+		}
+
+		if row.UserID.Valid {
+			player.UserID = &row.UserID.String
+			player.ID = PlayerID(row.UserID.String)
+		} else if row.GuestPlayerID.Valid {
+			player.ID = PlayerID(row.GuestPlayerID.String)
+		}
+
+		players = append(players, player)
+	}
+	return players
+}

game/store.go

@@ -1,40 +1,32 @@
 package game
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding/hex"
 	"sync"
+
+	"github.com/ryanhamamura/c4/db/repository"
 )
 
 type PlayerSession struct {
 	Player *Player
 }
 
-type Persister interface {
-	SaveGame(g *Game) error
-	LoadGame(id string) (*Game, error)
-	SaveGamePlayer(gameID string, player *Player, slot int) error
-	LoadGamePlayers(gameID string) ([]*Player, error)
-	DeleteGame(id string) error
-}
-
 type GameStore struct {
-	games     map[string]*GameInstance
-	gamesMu   sync.RWMutex
-	persister  Persister
+	games      map[string]*GameInstance
+	gamesMu    sync.RWMutex
+	queries    *repository.Queries
 	notifyFunc func(gameID string)
 }
 
-func NewGameStore() *GameStore {
+func NewGameStore(queries *repository.Queries) *GameStore {
 	return &GameStore{
-		games: make(map[string]*GameInstance),
+		games:   make(map[string]*GameInstance),
+		queries: queries,
 	}
 }
 
-func (gs *GameStore) SetPersister(p Persister) {
-	gs.persister = p
-}
-
 func (gs *GameStore) SetNotifyFunc(f func(gameID string)) {
 	gs.notifyFunc = f
 }
@@ -50,14 +42,14 @@ func (gs *GameStore) makeNotify(gameID string) func() {
 func (gs *GameStore) Create() *GameInstance {
 	id := GenerateID(4)
 	gi := NewGameInstance(id)
-	gi.persister = gs.persister
+	gi.queries = gs.queries
 	gi.notify = gs.makeNotify(id)
 	gs.gamesMu.Lock()
 	gs.games[id] = gi
 	gs.gamesMu.Unlock()
 
-	if gs.persister != nil {
-		gs.persister.SaveGame(gi.game)
+	if gs.queries != nil {
+		gs.saveGame(gi.game)
 	}
 
 	return gi
@@ -72,28 +64,28 @@ func (gs *GameStore) Get(id string) (*GameInstance, bool) {
 		return gi, true
 	}
 
-	if gs.persister == nil {
+	if gs.queries == nil {
 		return nil, false
 	}
 
-	game, err := gs.persister.LoadGame(id)
-	if err != nil || game == nil {
+	g, err := gs.loadGame(id)
+	if err != nil || g == nil {
 		return nil, false
 	}
 
-	players, _ := gs.persister.LoadGamePlayers(id)
+	players, _ := gs.loadGamePlayers(id)
 	for _, p := range players {
 		if p.Color == 1 {
-			game.Players[0] = p
+			g.Players[0] = p
 		} else if p.Color == 2 {
-			game.Players[1] = p
+			g.Players[1] = p
 		}
 	}
 
 	gi = &GameInstance{
-		game:      game,
-		persister: gs.persister,
-		notify:    gs.makeNotify(id),
+		game:    g,
+		queries: gs.queries,
+		notify:  gs.makeNotify(id),
 	}
 
 	gs.gamesMu.Lock()
@@ -108,8 +100,8 @@ func (gs *GameStore) Delete(id string) error {
 	delete(gs.games, id)
 	gs.gamesMu.Unlock()
 
-	if gs.persister != nil {
-		return gs.persister.DeleteGame(id)
+	if gs.queries != nil {
+		return gs.queries.DeleteGame(context.Background(), id)
 	}
 	return nil
 }
@@ -121,10 +113,10 @@ func GenerateID(size int) string {
 }
 
 type GameInstance struct {
-	game      *Game
-	gameMu    sync.RWMutex
-	notify    func()
-	persister Persister
+	game    *Game
+	gameMu  sync.RWMutex
+	notify  func()
+	queries *repository.Queries
 }
 
 func NewGameInstance(id string) *GameInstance {
@@ -158,9 +150,9 @@ func (gi *GameInstance) Join(ps *PlayerSession) bool {
 		return false
 	}
 
-	if gi.persister != nil {
-		gi.persister.SaveGamePlayer(gi.game.ID, ps.Player, slot)
-		gi.persister.SaveGame(gi.game)
+	if gi.queries != nil {
+		gi.saveGamePlayer(gi.game.ID, ps.Player, slot)
+		gi.saveGame(gi.game)
 	}
 
 	gi.notify()
@@ -196,8 +188,8 @@ func (gi *GameInstance) CreateRematch(gs *GameStore) *GameInstance {
 	newID := newGI.ID()
 	gi.game.RematchGameID = &newID
 
-	if gi.persister != nil {
-		if err := gi.persister.SaveGame(gi.game); err != nil {
+	if gi.queries != nil {
+		if err := gi.saveGame(gi.game); err != nil {
 			gs.Delete(newID)
 			gi.game.RematchGameID = nil
 			return nil
@@ -230,8 +222,8 @@ func (gi *GameInstance) DropPiece(col int, playerColor int) bool {
 		gi.game.SwitchTurn()
 	}
 
-	if gi.persister != nil {
-		gi.persister.SaveGame(gi.game)
+	if gi.queries != nil {
+		gi.saveGame(gi.game)
 	}
 
 	gi.notify()