Add play again button for rematch after game ends

When a game finishes (win or draw), players see a "Play again" button.
Clicking it creates a new game and the opponent sees a "Join Rematch"
link to join the same game.

db/gen/games.sql.go

@@ -13,7 +13,7 @@ import (
 const createGame = `-- name: CreateGame :one
 INSERT INTO games (id, board, current_turn, status)
 VALUES (?, ?, ?, ?)
-RETURNING id, board, current_turn, status, winner_user_id, winning_cells, created_at, updated_at
+RETURNING id, board, current_turn, status, winner_user_id, winning_cells, created_at, updated_at, rematch_game_id
 `
 
 type CreateGameParams struct {
@@ -40,6 +40,7 @@ func (q *Queries) CreateGame(ctx context.Context, arg CreateGameParams) (Game, e
 		&i.WinningCells,
 		&i.CreatedAt,
 		&i.UpdatedAt,
+		&i.RematchGameID,
 	)
 	return i, err
 }
@@ -80,7 +81,7 @@ func (q *Queries) DeleteGame(ctx context.Context, id string) error {
 }
 
 const getActiveGames = `-- name: GetActiveGames :many
-SELECT id, board, current_turn, status, winner_user_id, winning_cells, created_at, updated_at FROM games WHERE status < 2
+SELECT id, board, current_turn, status, winner_user_id, winning_cells, created_at, updated_at, rematch_game_id FROM games WHERE status < 2
 `
 
 func (q *Queries) GetActiveGames(ctx context.Context) ([]Game, error) {
@@ -101,6 +102,7 @@ func (q *Queries) GetActiveGames(ctx context.Context) ([]Game, error) {
 			&i.WinningCells,
 			&i.CreatedAt,
 			&i.UpdatedAt,
+			&i.RematchGameID,
 		); err != nil {
 			return nil, err
 		}
@@ -116,7 +118,7 @@ func (q *Queries) GetActiveGames(ctx context.Context) ([]Game, error) {
 }
 
 const getGame = `-- name: GetGame :one
-SELECT id, board, current_turn, status, winner_user_id, winning_cells, created_at, updated_at FROM games WHERE id = ?
+SELECT id, board, current_turn, status, winner_user_id, winning_cells, created_at, updated_at, rematch_game_id FROM games WHERE id = ?
 `
 
 func (q *Queries) GetGame(ctx context.Context, id string) (Game, error) {
@@ -131,6 +133,7 @@ func (q *Queries) GetGame(ctx context.Context, id string) (Game, error) {
 		&i.WinningCells,
 		&i.CreatedAt,
 		&i.UpdatedAt,
+		&i.RematchGameID,
 	)
 	return i, err
 }
@@ -171,7 +174,7 @@ func (q *Queries) GetGamePlayers(ctx context.Context, gameID string) ([]GamePlay
 }
 
 const getGamesByUserID = `-- name: GetGamesByUserID :many
-SELECT g.id, g.board, g.current_turn, g.status, g.winner_user_id, g.winning_cells, g.created_at, g.updated_at FROM games g
+SELECT g.id, g.board, g.current_turn, g.status, g.winner_user_id, g.winning_cells, g.created_at, g.updated_at, g.rematch_game_id FROM games g
 JOIN game_players gp ON g.id = gp.game_id
 WHERE gp.user_id = ?
 ORDER BY g.updated_at DESC
@@ -195,6 +198,7 @@ func (q *Queries) GetGamesByUserID(ctx context.Context, userID sql.NullString) (
 			&i.WinningCells,
 			&i.CreatedAt,
 			&i.UpdatedAt,
+			&i.RematchGameID,
 		); err != nil {
 			return nil, err
 		}
@@ -265,7 +269,7 @@ func (q *Queries) GetUserActiveGames(ctx context.Context, userID sql.NullString)
 
 const updateGame = `-- name: UpdateGame :exec
 UPDATE games
-SET board = ?, current_turn = ?, status = ?, winner_user_id = ?, winning_cells = ?, updated_at = CURRENT_TIMESTAMP
+SET board = ?, current_turn = ?, status = ?, winner_user_id = ?, winning_cells = ?, rematch_game_id = ?, updated_at = CURRENT_TIMESTAMP
 WHERE id = ?
 `
 
@@ -275,6 +279,7 @@ type UpdateGameParams struct {
 	Status        int64
 	WinnerUserID  sql.NullString
 	WinningCells  sql.NullString
+	RematchGameID sql.NullString
 	ID            string
 }
 
@@ -285,6 +290,7 @@ func (q *Queries) UpdateGame(ctx context.Context, arg UpdateGameParams) error {
 		arg.Status,
 		arg.WinnerUserID,
 		arg.WinningCells,
+		arg.RematchGameID,
 		arg.ID,
 	)
 	return err

db/gen/models.go

@@ -17,6 +17,7 @@ type Game struct {
 	WinningCells  sql.NullString
 	CreatedAt     sql.NullTime
 	UpdatedAt     sql.NullTime
+	RematchGameID sql.NullString
 }
 
 type GamePlayer struct {

db/migrations/002_add_rematch.sql

@@ -0,0 +1,5 @@
+-- +goose Up
+ALTER TABLE games ADD COLUMN rematch_game_id TEXT;
+
+-- +goose Down
+ALTER TABLE games DROP COLUMN rematch_game_id;

db/persister.go

@@ -43,12 +43,18 @@ func (p *GamePersister) SaveGame(g *game.Game) error {
 		winningCells = sql.NullString{String: wc, Valid: true}
 	}
 
+	rematchGameID := sql.NullString{}
+	if g.RematchGameID != nil {
+		rematchGameID = sql.NullString{String: *g.RematchGameID, Valid: true}
+	}
+
 	return p.queries.UpdateGame(ctx, gen.UpdateGameParams{
 		Board:         g.BoardToJSON(),
 		CurrentTurn:   int64(g.CurrentTurn),
 		Status:        int64(g.Status),
 		WinnerUserID:  winnerUserID,
 		WinningCells:  winningCells,
+		RematchGameID: rematchGameID,
 		ID:            g.ID,
 	})
 }
@@ -74,6 +80,10 @@ func (p *GamePersister) LoadGame(id string) (*game.Game, error) {
 		g.WinningCellsFromJSON(row.WinningCells.String)
 	}
 
+	if row.RematchGameID.Valid {
+		g.RematchGameID = &row.RematchGameID.String
+	}
+
 	return g, nil
 }
 

db/queries/games.sql

@@ -8,7 +8,7 @@ SELECT * FROM games WHERE id = ?;
 
 -- name: UpdateGame :exec
 UPDATE games
-SET board = ?, current_turn = ?, status = ?, winner_user_id = ?, winning_cells = ?, updated_at = CURRENT_TIMESTAMP
+SET board = ?, current_turn = ?, status = ?, winner_user_id = ?, winning_cells = ?, rematch_game_id = ?, updated_at = CURRENT_TIMESTAMP
 WHERE id = ?;
 
 -- name: DeleteGame :exec

game/store.go

@@ -196,6 +196,30 @@ func (gi *GameInstance) GetPlayerColor(pid PlayerID) int {
 	return 0
 }
 
+func (gi *GameInstance) CreateRematch(gs *GameStore) *GameInstance {
+	gi.gameMu.Lock()
+	defer gi.gameMu.Unlock()
+
+	if !gi.game.IsFinished() || gi.game.RematchGameID != nil {
+		return nil
+	}
+
+	newGI := gs.Create()
+	newID := newGI.ID()
+	gi.game.RematchGameID = &newID
+
+	if gi.persister != nil {
+		if err := gi.persister.SaveGame(gi.game); err != nil {
+			gs.Delete(newID)
+			gi.game.RematchGameID = nil
+			return nil
+		}
+	}
+
+	gi.dirty = true
+	return newGI
+}
+
 func (gi *GameInstance) DropPiece(col int, playerColor int) bool {
 	gi.gameMu.Lock()
 	defer gi.gameMu.Unlock()

game/types.go

@@ -28,6 +28,7 @@ type Game struct {
 	Status        GameStatus
 	Winner        *Player
 	WinningCells  [][2]int // Coordinates of winning 4 cells for highlighting
+	RematchGameID *string  // ID of the rematch game, if one was created
 }
 
 func NewGame(id string) *Game {
@@ -39,6 +40,10 @@ func NewGame(id string) *Game {
 	}
 }
 
+func (g *Game) IsFinished() bool {
+	return g.Status == StatusWon || g.Status == StatusDraw
+}
+
 func (g *Game) BoardToJSON() string {
 	data, _ := json.Marshal(g.Board)
 	return string(data)

main.go

@@ -281,6 +281,16 @@ func main() {
 			c.Sync()
 		})
 
+		createRematch := c.Action(func() {
+			if gi == nil {
+				return
+			}
+			newGI := gi.CreateRematch(store)
+			if newGI != nil {
+				c.Redirectf("/game/%s", newGI.ID())
+			}
+		})
+
 		// If nickname exists in session and game exists, join immediately
 		if gameExists && sessionNickname != "" && gi.GetPlayerColor(playerID) == 0 {
 			player := &game.Player{
@@ -325,7 +335,7 @@ func main() {
 			content = append(content,
 				h.H1(h.Text("Connect 4")),
 				ui.PlayerInfo(g, myColor),
-				ui.StatusBanner(g, myColor),
+				ui.StatusBanner(g, myColor, createRematch.OnClick()),
 				ui.BoardComponent(g, columnClick, myColor),
 			)
 
@@ -444,6 +454,22 @@ const gameCSS = `
 		color: white;
 	}
 
+	.play-again-btn, .rematch-link {
+		margin-left: 1rem;
+		padding: 0.25rem 0.75rem;
+		font-size: 0.875rem;
+		background: white;
+		color: #333;
+		border: none;
+		border-radius: 4px;
+		cursor: pointer;
+		text-decoration: none;
+	}
+
+	.play-again-btn:hover, .rematch-link:hover {
+		background: #eee;
+	}
+
 	.player-info {
 		display: flex;
 		gap: 2rem;

ui/status.go

@@ -5,7 +5,7 @@ import (
 	"github.com/ryanhamamura/via/h"
 )
 
-func StatusBanner(g *game.Game, myColor int) h.H {
+func StatusBanner(g *game.Game, myColor int, playAgainClick h.H) h.H {
 	var message string
 	var class string
 
@@ -35,10 +35,34 @@ func StatusBanner(g *game.Game, myColor int) h.H {
 		class = "status draw"
 	}
 
-	return h.Div(
+	content := []h.H{
 		h.Class(class),
 		h.Text(message),
+	}
+
+	// Show rematch options for finished games
+	if g.IsFinished() {
+		if g.RematchGameID != nil {
+			content = append(content,
+				h.A(
+					h.Class("rematch-link"),
+					h.Href("/game/"+*g.RematchGameID),
+					h.Text("Join Rematch"),
+				),
 			)
+		} else if playAgainClick != nil {
+			content = append(content,
+				h.Button(
+					h.Class("play-again-btn"),
+					h.Type("button"),
+					h.Text("Play again"),
+					playAgainClick,
+				),
+			)
+		}
+	}
+
+	return h.Div(content...)
 }
 
 func getOpponentName(g *game.Game, myColor int) string {