feat: persist chat messages to SQLite

Chat messages were ephemeral — lost on page refresh or late join.
Add a chat_messages table and load the last 50 messages on connect
so players see conversation history.

db/gen/chat.sql.go

@@ -0,0 +1,71 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.30.0
+// source: chat.sql
+
+package gen
+
+import (
+	"context"
+)
+
+const createChatMessage = `-- name: CreateChatMessage :exec
+INSERT INTO chat_messages (game_id, nickname, color, message, created_at)
+VALUES (?, ?, ?, ?, ?)
+`
+
+type CreateChatMessageParams struct {
+	GameID    string
+	Nickname  string
+	Color     int64
+	Message   string
+	CreatedAt int64
+}
+
+func (q *Queries) CreateChatMessage(ctx context.Context, arg CreateChatMessageParams) error {
+	_, err := q.db.ExecContext(ctx, createChatMessage,
+		arg.GameID,
+		arg.Nickname,
+		arg.Color,
+		arg.Message,
+		arg.CreatedAt,
+	)
+	return err
+}
+
+const getChatMessages = `-- name: GetChatMessages :many
+SELECT id, game_id, nickname, color, message, created_at FROM chat_messages
+WHERE game_id = ?
+ORDER BY created_at DESC, id DESC
+LIMIT 50
+`
+
+func (q *Queries) GetChatMessages(ctx context.Context, gameID string) ([]ChatMessage, error) {
+	rows, err := q.db.QueryContext(ctx, getChatMessages, gameID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ChatMessage
+	for rows.Next() {
+		var i ChatMessage
+		if err := rows.Scan(
+			&i.ID,
+			&i.GameID,
+			&i.Nickname,
+			&i.Color,
+			&i.Message,
+			&i.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Close(); err != nil {
+		return nil, err
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}

db/gen/models.go

@@ -8,6 +8,15 @@ import (
 	"database/sql"
 )
 
+type ChatMessage struct {
+	ID        int64
+	GameID    string
+	Nickname  string
+	Color     int64
+	Message   string
+	CreatedAt int64
+}
+
 type Game struct {
 	ID            string
 	Board         string

db/migrations/006_add_chat_messages.sql

@@ -0,0 +1,15 @@
+-- +goose Up
+CREATE TABLE chat_messages (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    game_id TEXT NOT NULL,
+    nickname TEXT NOT NULL,
+    color INTEGER NOT NULL,
+    message TEXT NOT NULL,
+    created_at INTEGER NOT NULL,
+    FOREIGN KEY (game_id) REFERENCES games(id) ON DELETE CASCADE
+);
+CREATE INDEX idx_chat_messages_game ON chat_messages(game_id, created_at);
+
+-- +goose Down
+DROP INDEX IF EXISTS idx_chat_messages_game;
+DROP TABLE IF EXISTS chat_messages;

db/persister.go

@@ -3,10 +3,12 @@ package db
 import (
 	"context"
 	"database/sql"
+	"slices"
 
 	"github.com/ryanhamamura/c4/db/gen"
 	"github.com/ryanhamamura/c4/game"
 	"github.com/ryanhamamura/c4/snake"
+	"github.com/ryanhamamura/c4/ui"
 )
 
 type GamePersister struct {
@@ -286,3 +288,40 @@ func (p *SnakePersister) DeleteSnakeGame(id string) error {
 	ctx := context.Background()
 	return p.queries.DeleteSnakeGame(ctx, id)
 }
+
+type ChatPersister struct {
+	queries *gen.Queries
+}
+
+func NewChatPersister(q *gen.Queries) *ChatPersister {
+	return &ChatPersister{queries: q}
+}
+
+func (p *ChatPersister) SaveChatMessage(gameID string, msg ui.C4ChatMessage) error {
+	return p.queries.CreateChatMessage(context.Background(), gen.CreateChatMessageParams{
+		GameID:    gameID,
+		Nickname:  msg.Nickname,
+		Color:     int64(msg.Color),
+		Message:   msg.Message,
+		CreatedAt: msg.Time,
+	})
+}
+
+func (p *ChatPersister) LoadChatMessages(gameID string) ([]ui.C4ChatMessage, error) {
+	rows, err := p.queries.GetChatMessages(context.Background(), gameID)
+	if err != nil {
+		return nil, err
+	}
+	msgs := make([]ui.C4ChatMessage, len(rows))
+	for i, r := range rows {
+		msgs[i] = ui.C4ChatMessage{
+			Nickname: r.Nickname,
+			Color:    int(r.Color),
+			Message:  r.Message,
+			Time:     r.CreatedAt,
+		}
+	}
+	// Query returns newest-first; reverse to oldest-first for display
+	slices.Reverse(msgs)
+	return msgs, nil
+}

db/queries/chat.sql

@@ -0,0 +1,9 @@
+-- name: CreateChatMessage :exec
+INSERT INTO chat_messages (game_id, nickname, color, message, created_at)
+VALUES (?, ?, ?, ?, ?);
+
+-- name: GetChatMessages :many
+SELECT * FROM chat_messages
+WHERE game_id = ?
+ORDER BY created_at DESC, id DESC
+LIMIT 50;

main.go

@@ -27,9 +27,10 @@ import (
 )
 
 var (
-	store      = game.NewGameStore()
-	snakeStore = snake.NewSnakeStore()
-	queries    *gen.Queries
+	store         = game.NewGameStore()
+	snakeStore    = snake.NewSnakeStore()
+	queries       *gen.Queries
+	chatPersister *db.ChatPersister
 )
 
 //go:embed assets
@@ -61,6 +62,7 @@ func main() {
 	queries = gen.New(db.DB)
 	store.SetPersister(db.NewGamePersister(queries))
 	snakeStore.SetPersister(db.NewSnakePersister(queries))
+	chatPersister = db.NewChatPersister(queries)
 
 	sessionManager, err := via.NewSQLiteSessionManager(db.DB)
 	if err != nil {
@@ -356,7 +358,7 @@ func main() {
 		colSignal := c.Signal(0)
 		showGuestPrompt := c.Signal(false)
 		chatMsg := c.Signal("")
-		var chatMessages []ui.C4ChatMessage
+		chatMessages, _ := chatPersister.LoadChatMessages(gameID)
 		var chatMu sync.Mutex
 
 		goToLogin := c.Action(func() {
@@ -462,6 +464,7 @@ func main() {
 				Message:  msg,
 				Time:     time.Now().UnixMilli(),
 			}
+			chatPersister.SaveChatMessage(gameID, cm)
 			data, err := json.Marshal(cm)
 			if err != nil {
 				return