1 files changed, 83 insertions, 0 deletions
diff --git a/internal/casino/seats.go b/internal/casino/seats.go
new file mode 100644
index 0000000..6f44d6b
--- /dev/null
+++ b/internal/casino/seats.go
@@ -0,0 +1,83 @@
+package casino
+
+// seatedPlayer is implemented by every table-game player type; they all embed
+// Participant and expose it here so the seat set can manage shared state
+// (connection, wagers) without knowing game-specific fields.
+type seatedPlayer interface {
+	participantPtr() *Participant
+}
+
+// seatSet tracks the ordered occupants of a multiplayer table. It owns the
+// participant map and seat-order slice every table game used to maintain by
+// hand; game structs keep their own player type and delegate the plumbing.
+type seatSet[P seatedPlayer] struct {
+	order   []string
+	players map[string]P
+}
+
+func newSeatSet[P seatedPlayer]() seatSet[P] {
+	return seatSet[P]{players: make(map[string]P)}
+}
+
+func (s *seatSet[P]) get(name string) P { return s.players[name] }
+
+func (s *seatSet[P]) has(name string) bool {
+	_, ok := s.players[name]
+	return ok
+}
+
+// count reports the number of seated players.
+func (s *seatSet[P]) count() int { return len(s.order) }
+
+// nameAt returns the player name at a seat index, or "" when out of range.
+func (s *seatSet[P]) nameAt(i int) string {
+	if i < 0 || i >= len(s.order) {
+		return ""
+	}
+	return s.order[i]
+}
+
+// indexOf returns the seat index of a player, or -1 when not seated.
+func (s *seatSet[P]) indexOf(name string) int {
+	for i, n := range s.order {
+		if n == name {
+			return i
+		}
+	}
+	return -1
+}
+
+func (s *seatSet[P]) add(name string, p P) {
+	s.players[name] = p
+	s.order = append(s.order, name)
+}
+
+func (s *seatSet[P]) remove(name string) {
+	delete(s.players, name)
+	for i, n := range s.order {
+		if n == name {
+			s.order = append(s.order[:i], s.order[i+1:]...)
+			break
+		}
+	}
+}
+
+// ordered lists the seated players in seat order.
+func (s *seatSet[P]) ordered() []P {
+	out := make([]P, 0, len(s.order))
+	for _, name := range s.order {
+		if p, ok := s.players[name]; ok {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+// participants is the seat-ordered shared view used by the betting helpers.
+func (s *seatSet[P]) participants() []*Participant {
+	out := make([]*Participant, 0, len(s.order))
+	for _, p := range s.ordered() {
+		out = append(out, p.participantPtr())
+	}
+	return out
+}