add games lobby

go.mod

@@ -1,3 +1,5 @@
 module git.sunturtle.xyz/studio/shotgun
 
-go 1.21.3
+go 1.21.6
+
+require github.com/google/uuid v1.5.0

go.sum

@@ -0,0 +1,2 @@
+github.com/google/uuid v1.5.0 h1:1p67kYwdtXjb0gL0BPiP1Av9wiZPo5A8z2cWkTZ+eyU=
+github.com/google/uuid v1.5.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=

lobby/lobby.go

@@ -0,0 +1,48 @@
+package serve
+
+import (
+	"sync"
+
+	"github.com/google/uuid"
+
+	"git.sunturtle.xyz/studio/shotgun/game"
+)
+
+type GameID = uuid.UUID
+
+// Lobby is a set of active games.
+type Lobby struct {
+	mu sync.Mutex
+	// games is the set of all active games in the lobby.
+	games map[GameID]*game.Game
+}
+
+func New() *Lobby {
+	return &Lobby{
+		games: make(map[GameID]*game.Game),
+	}
+}
+
+// Game returns the game with the given ID.
+func (l *Lobby) Game(id GameID) *game.Game {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.games[id]
+}
+
+// Start starts a new game in the lobby.
+func (l *Lobby) Start() GameID {
+	id := uuid.New()
+	g := game.New()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.games[id] = g
+	return id
+}
+
+// Finish removes a game from the lobby.
+func (l *Lobby) Finish(id GameID) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	delete(l.games, id)
+}